This is to receive 0a30288da1 ("blk-mq, percpu_ref: implement a
kludge for SCSI blk-mq stall during probe") which implements
__percpu_ref_kill_expedited() to work around SCSI blk-mq stall. The
commit reverted and patches to implement proper fix will be added.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
This reverts commit 1f9a7268c6.
With the fix of the initial state for the cloned event we now correctly
handle the error described in:
1f9a7268c6 perf: Do not allow optimized switch for non-cloned events
so we can revert it.
I made an automated test for this, but its not suitable for automated
perf tests framework. It needs to be customized for each machine (the
more cpu the higher numbers for GROUPS/WORKERS/BYTES) and it could take
longer time to hit the issue.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140910143535.GD2409@krava.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently we initialize the child event based on the original
parent state. This is wrong, because the original parent event
(and its state) is not related to current fork and also could
be already gone.
We need to initialize the child state based on the immediate
parent event state.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410520708-19275-2-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently we return POLLHUP in event polling if the monitored
process is done, but we didn't consider possible children,
that might be still running and producing data.
Before returning POLLHUP making sure that:
1) the monitored task has exited and that
2) we don't have any children to monitor
Also adding parent wakeup when the child event is gone.
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1410520708-19275-1-git-send-email-jolsa@kernel.org
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Some time ago PREEMPT_NEED_RESCHED was implemented,
so reschedule technics is a little more difficult now.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183642.11015.66039.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Probability of use-after-free isn't zero in this place.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183636.11015.83611.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Nothing is locked there, so label's name only confuses a reader.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140922183630.11015.59500.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
dl_bw_of() dereferences rq->rd which has to have RCU read lock held.
Probability of use-after-free isn't zero here.
Also add lockdep assert into dl_bw_cpus().
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140922183624.11015.71558.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
read_lock_irqsave(tasklist_lock) in print_rq() looks strange. We do
not need to disable irqs, and they are already disabled by the caller.
And afaics this lock buys nothing, we can rely on rcu_read_lock().
In this case it makes sense to also move rcu_read_lock/unlock from
the caller to print_rq().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921193341.GA28628@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1. read_lock(tasklist_lock) does not need to disable irqs.
2. ->mm != NULL is a common mistake, use PF_KTHREAD.
3. The second ->mm check can be simply removed.
4. task_rq_lock() looks better than raw_spin_lock(&p->pi_lock) +
__task_rq_lock().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921193338.GA28621@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
tg_has_rt_tasks() wants to find an RT task in this task_group, but
task_rq(p)->rt.tg wrongly checks the root rt_rq.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Link: http://lkml.kernel.org/r/20140921193336.GA28618@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The code in find_idlest_cpu() looks for the CPU with the smallest load.
However, if multiple CPUs are idle, the first idle CPU is selected
irrespective of the depth of its idle state.
Among the idle CPUs we should pick the one with with the shallowest idle
state, or the latest to have gone idle if all idle CPUs are in the same
state. The later applies even when cpuidle is configured out.
This patch doesn't cover the following issues:
- The idle exit latency of a CPU might be larger than the time needed
to migrate the waking task to an already running CPU with sufficient
capacity, and therefore performance would benefit from task packing
in such case (in most cases task packing is about power saving).
- Some idle states have a non negligible and non abortable entry latency
which needs to run to completion before the exit latency can start.
A concurrent patch series is making this info available to the cpuidle
core. Once available, the entry latency with the idle timestamp could
determine when the exit latency may be effective.
Those issues will be handled in due course. In the mean time, what
is implemented here should improve things already compared to the current
state of affairs.
Based on an initial patch from Daniel Lezcano.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-pm@vger.kernel.org
Cc: linaro-kernel@lists.linaro.org
Link: http://lkml.kernel.org/n/tip-@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When the cpu enters idle, it stores the cpuidle state pointer in its
struct rq instance which in turn could be used to make a better decision
when balancing tasks.
As soon as the cpu exits its idle state, the struct rq reference is
cleared.
There are a couple of situations where the idle state pointer could be changed
while it is being consulted:
1. For x86/acpi with dynamic c-states, when a laptop switches from battery
to AC that could result on removing the deeper idle state. The acpi driver
triggers:
'acpi_processor_cst_has_changed'
'cpuidle_pause_and_lock'
'cpuidle_uninstall_idle_handler'
'kick_all_cpus_sync'.
All cpus will exit their idle state and the pointed object will be set to
NULL.
2. The cpuidle driver is unloaded. Logically that could happen but not
in practice because the drivers are always compiled in and 95% of them are
not coded to unregister themselves. In any case, the unloading code must
call 'cpuidle_unregister_device', that calls 'cpuidle_pause_and_lock'
leading to 'kick_all_cpus_sync' as mentioned above.
A race can happen if we use the pointer and then one of these two scenarios
occurs at the same moment.
In order to be safe, the idle state pointer stored in the rq must be
used inside a rcu_read_lock section where we are protected with the
'rcu_barrier' in the 'cpuidle_uninstall_idle_handler' function. The
idle_get_state() and idle_put_state() accessors should be used to that
effect.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Cc: linaro-kernel@lists.linaro.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Users can perform clustered scheduling using the cpuset facility.
After an exclusive cpuset is created, task migrations happen only
between CPUs belonging to the same cpuset. Inter- cpuset migrations
can only happen when the user requires so, moving a task between
different cpusets. This behaviour is broken in SCHED_DEADLINE, as
currently spurious inter- cpuset migration may happen without user
intervention.
This patch fix the problem (and shuffles the code a bit to improve
clarity).
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: raistlin@linux.it
Cc: michael@amarulasolutions.com
Cc: fchecconi@gmail.com
Cc: daniel.wagner@bmw-carit.de
Cc: vincent@legout.info
Cc: luca.abeni@unitn.it
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1411118561-26323-4-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When a task is using SCHED_DEADLINE and the user setschedules it to a
different class its sched_dl_entity static parameters are not cleaned
up. This causes a bug if the user sets it back to SCHED_DEADLINE with
the same parameters again. The problem resides in the check we
perform at the very beginning of dl_overflow():
if (new_bw == p->dl.dl_bw)
return 0;
This condition is met in the case depicted above, so the function
returns and dl_b->total_bw is not updated (the p->dl.dl_bw is not
added to it). After this, admission control is broken.
This patch fixes the thing, properly clearing static parameters for a
task that ceases to use SCHED_DEADLINE.
Reported-by: Daniele Alessandrelli <daniele.alessandrelli@gmail.com>
Reported-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Reported-by: Vincent Legout <vincent@legout.info>
Tested-by: Luca Abeni <luca.abeni@unitn.it>
Tested-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Tested-by: Vincent Legout <vincent@legout.info>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Fabio Checconi <fchecconi@gmail.com>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1411118561-26323-2-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
current->state == TASK_DEAD means that the task is doing its
last schedule(), page fault is obviously impossible at this
stage.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921194743.GA30114@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When task->comm is passed directly to audit_log_untrustedstring() without
getting a copy or using the task_lock, there is a race that could happen that
would output a NULL (\0) in the output string that would effectively truncate
the rest of the report text after the comm= field in the audit, losing fields.
Use get_task_comm() to get a copy while acquiring the task_lock to prevent
this and to prevent the result from being a mixture of old and new values of
comm.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
When an AUDIT_GET_FEATURE message is sent from userspace to the kernel, it
should reply with a message tagged as an AUDIT_GET_FEATURE type with a struct
audit_feature. The current reply is a message tagged as an AUDIT_GET
type with a struct audit_feature.
This appears to have been a cut-and-paste-eo in commit b0fed40.
Reported-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Report:
Looking at your example code in
http://people.redhat.com/rbriggs/audit-multicast-listen/audit-multicast-listen.c,
it seems that nlmsg_len field in the received messages is supposed to
contain the length of the header + payload, but it is always set to the
size of the header only, i.e. 16. The example program works, because
the printf format specifies the minimum width, not "precision", so it
simply prints out the payload until the first zero byte. This isn't too
much of a problem, but precludes the use of recvmmsg, iiuc?
(gdb) p *(struct nlmsghdr*)nlh
$14 = {nlmsg_len = 16, nlmsg_type = 1100, nlmsg_flags = 0, nlmsg_seq = 0, nlmsg_pid = 9910}
The only time nlmsg_len would have been updated was at audit_buffer_alloc()
inside audit_log_start() and never updated after. It should arguably be done
in audit_log_vformat(), but would be more efficient in audit_log_end().
Reported-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Since only one of val, uid, gid and lsm* are used at any given time, combine
them to reduce the size of the struct audit_field.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Various audit events dealing with adding, removing and updating rules result in
invalid values set for the op keys which result in embedded spaces in op=
values.
The invalid values are
op="add rule" set in kernel/auditfilter.c
op="remove rule" set in kernel/auditfilter.c
op="remove rule" set in kernel/audit_tree.c
op="updated rules" set in kernel/audit_watch.c
op="remove rule" set in kernel/audit_watch.c
Replace the space in the above values with an underscore character ('_').
Coded-by: Burn Alting <burn@swtf.dyndns.org>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Since there is already a primitive to do this operation in the atomic_t, use it
to simplify audit_serial().
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Use kernel.h definition.
Cc: Eric Paris <eparis@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Since the arch is found locally in __audit_syscall_entry(), there is no need to
pass it in as a parameter. Delete it from the parameter list.
x86* was the only arch to call __audit_syscall_entry() directly and did so from
assembly code.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-audit@redhat.com
Signed-off-by: Eric Paris <eparis@redhat.com>
---
As this patch relies on changes in the audit tree, I think it
appropriate to send it through my tree rather than the x86 tree.
The AUDIT_SECCOMP record looks something like this:
type=SECCOMP msg=audit(1373478171.953:32775): auid=4325 uid=4325 gid=4325 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0 pid=12381 comm="test" sig=31 syscall=231 compat=0 ip=0x39ea8bca89 code=0x0
In order to determine what syscall 231 maps to, we need to have the arch= field right before it.
To see the event, compile this test.c program:
=====
int main(void)
{
return seccomp_load(seccomp_init(SCMP_ACT_KILL));
}
=====
gcc -g test.c -o test -lseccomp
After running the program, find the record by: ausearch --start recent -m SECCOMP -i
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
signed-off-by: Eric Paris <eparis@redhat.com>
Since every arch should have syscall_get_arch() defined, stop using the
function argument and just collect this ourselves. We do not drop the
argument as fixing some code paths (in assembly) to not pass this first
argument is non-trivial. The argument will be dropped when that is
fixed.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Conflicts:
arch/mips/net/bpf_jit.c
drivers/net/can/flexcan.c
Both the flexcan and MIPS bpf_jit conflicts were cases of simple
overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull cgroup fix from Tejun Heo:
"One late fix for cgroup.
I was waiting for another set of fixes for a long-standing obscure
cpuset bug but am not sure whether they'll be ready before v3.17
release. This one is a simple fix for a mutex unlock balance bug in
an allocation failure path in pidlist_array_load().
The bug was introduced in v3.14 and the fix is tagged for -stable"
* 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: fix unbalanced locking
This patch moves Exynos PM domain code to use the new generic PM domain
look-up framework introduced in previous patches, thus also allowing
the new code to be compiled with CONFIG_ARCH_EXYNOS.
This patch was originally submitted by Tomasz Figa when he was employed
by Samsung.
Link: http://marc.info/?l=linux-pm&m=139955336002083&w=2
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch introduces generic code to perform PM domain look-up using
device tree and automatically bind devices to their PM domains.
Generic device tree bindings are introduced to specify PM domains of
devices in their device tree nodes.
Backwards compatibility with legacy Samsung-specific PM domain bindings
is provided, but for now the new code is not compiled when
CONFIG_ARCH_EXYNOS is selected to avoid collision with legacy code.
This will change as soon as the Exynos PM domain code gets converted to
use the generic framework in further patch.
This patch was originally submitted by Tomasz Figa when he was employed
by Samsung.
Link: http://marc.info/?l=linux-pm&m=139955349702152&w=2
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch adds another suspend_resume trace event for analyze_suspend
to capture. The resume_console call can take several hundred milliseconds
if the printk buffer is full of debug info. The tool will now inform
testers of the wasted time and encourage them to disable it in
production builds.
Signed-off-by: Todd Brandt <todd.e.brandt@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Both pinned_sb and new_sb indicate if a new superblock is needed,
so we can just remove new_sb.
Note now we must check if kernfs_tryget_sb() returns NULL, because
when it returns NULL, kernfs_mount() may still re-use an existing
superblock, which is just allocated by another concurent mount.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The patch 971ff49355: "cgroup: use a per-cgroup work for release
agent" from Sep 18, 2014, leads to the following static checker
warning:
kernel/cgroup.c:5310 cgroup_release_agent()
warn: 'mutex:&cgroup_mutex' is sometimes locked here and sometimes unlocked.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull perf fixes from Ingo Molnar:
"Two kernel side fixes: a kprobes fix and a perf_remove_from_context()
fix (which does not yet fix the migration bug which is WIP)"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Fix a race condition in perf_remove_from_context()
kprobes/x86: Free 'optinsn' cache when range check fails
We call put_css_set() after setting CGRP_RELEASABLE flag in
cgroup_task_migrate(), but in other places we call it without setting
the flag. I don't see the necessity of this flag.
Moreover once the flag is set, it will never be cleared, unless writing
to the notify_on_release control file, so it can be quite confusing
if we look at the output of debug.releasable.
# mount -t cgroup -o debug xxx /cgroup
# mkdir /cgroup/child
# cat /cgroup/child/debug.releasable
0 <-- shows 0 though the cgroup is empty
# echo $$ > /cgroup/child/tasks
# cat /cgroup/child/debug.releasable
0
# echo $$ > /cgroup/tasks && echo $$ > /cgroup/child/tasks
# cat /proc/child/debug.releasable
1 <-- shows 1 though the cgroup is not empty
This patch removes the flag, and now debug.releasable shows if the
cgroup is empty or not.
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
'capacity_orig' is only changed for systems with an SMT sched_domain level in order
to reflect the lower capacity of CPUs. Heterogenous systems also have to reflect an
original capacity that is different from the default value.
Create a more generic function arch_scale_cpu_capacity that can be also used by
non SMT platforms to set capacity_orig.
The __weak implementation of arch_scale_cpu_capacity() is the previous SMT variant,
in order to keep backward compatibility with the use of capacity_orig.
arch_scale_smt_capacity() and default_scale_smt_capacity() have been removed as
they were not used elsewhere than in arch_scale_cpu_capacity().
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Reviewed-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
[ Added default_scale_cpu_capacity() back. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: riel@redhat.com
Cc: Morten.Rasmussen@arm.com
Cc: efault@gmx.de
Cc: nicolas.pitre@linaro.org
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409051215-16788-5-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In wake_affine() I have tried to understand the meaning of the condition:
(this_load <= load &&
this_load + target_load(prev_cpu, idx) <= tl_per_task)
but I failed to find a use case that can take advantage of it and I haven't
found clear description in the previous commit's log.
Futhermore, the comment of the condition refers to the task_hot function that
was used before being replaced by the current condition:
/*
* This domain has SD_WAKE_AFFINE and
* p is cache cold in this domain, and
* there is no bad imbalance.
*/
If we look more deeply the below condition:
this_load + target_load(prev_cpu, idx) <= tl_per_task
When sync is clear, we have:
tl_per_task = runnable_load_avg / nr_running
this_load = max(runnable_load_avg, cpuload[idx])
target_load = max(runnable_load_avg', cpuload'[idx])
It implies that runnable_load_avg == 0 and nr_running <= 1 in order to match the
condition. This implies that runnable_load_avg == 0 too because of the
condition: this_load <= load.
but if this _load is null, 'balanced' is already set and the test is redundant.
If sync is set, it's not as straight forward as above (especially if cgroup
are involved) but the policy should be similar as we have removed a task that's
going to sleep in order to get a more accurate load and this_load values.
The current conclusion is that these additional condition don't give any benefit
so we can remove them.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: preeti@linux.vnet.ibm.com
Cc: riel@redhat.com
Cc: Morten.Rasmussen@arm.com
Cc: efault@gmx.de
Cc: nicolas.pitre@linaro.org
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409051215-16788-3-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The imbalance flag can stay set whereas there is no imbalance.
Let assume that we have 3 tasks that run on a dual cores /dual cluster system.
We will have some idle load balance which are triggered during tick.
Unfortunately, the tick is also used to queue background work so we can reach
the situation where short work has been queued on a CPU which already runs a
task. The load balance will detect this imbalance (2 tasks on 1 CPU and an idle
CPU) and will try to pull the waiting task on the idle CPU. The waiting task is
a worker thread that is pinned on a CPU so an imbalance due to pinned task is
detected and the imbalance flag is set.
Then, we will not be able to clear the flag because we have at most 1 task on
each CPU but the imbalance flag will trig to useless active load balance
between the idle CPU and the busy CPU.
We need to reset of the imbalance flag as soon as we have reached a balanced
state. If all tasks are pinned, we don't consider that as a balanced state and
let the imbalance flag set.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: riel@redhat.com
Cc: Morten.Rasmussen@arm.com
Cc: efault@gmx.de
Cc: nicolas.pitre@linaro.org
Cc: daniel.lezcano@linaro.org
Cc: dietmar.eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409051215-16788-2-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently in the event of a stack overrun a call to schedule()
does not check for this type of corruption. This corruption is
often silent and can go unnoticed. However once the corrupted
region is examined at a later stage, the outcome is undefined
and often results in a sporadic page fault which cannot be
handled.
This patch checks for a stack overrun and takes appropriate
action since the damage is already done, there is no point
in continuing.
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: aneesh.kumar@linux.vnet.ibm.com
Cc: dzickus@redhat.com
Cc: bmr@redhat.com
Cc: jcastillo@redhat.com
Cc: oleg@redhat.com
Cc: riel@redhat.com
Cc: prarit@redhat.com
Cc: jgh@redhat.com
Cc: minchan@kernel.org
Cc: mpe@ellerman.id.au
Cc: tglx@linutronix.de
Cc: rostedt@goodmis.org
Cc: hannes@cmpxchg.org
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lubomir Rintel <lkundrak@v3.sk>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1410527779-8133-4-git-send-email-atomlin@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tasks get their end of stack set to STACK_END_MAGIC with the
aim to catch stack overruns. Currently this feature does not
apply to init_task. This patch removes this restriction.
Note that a similar patch was posted by Prarit Bhargava
some time ago but was never merged:
http://marc.info/?l=linux-kernel&m=127144305403241&w=2
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: aneesh.kumar@linux.vnet.ibm.com
Cc: dzickus@redhat.com
Cc: bmr@redhat.com
Cc: jcastillo@redhat.com
Cc: jgh@redhat.com
Cc: minchan@kernel.org
Cc: tglx@linutronix.de
Cc: hannes@cmpxchg.org
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Daeseok Youn <daeseok.youn@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1410527779-8133-2-git-send-email-atomlin@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
If a task is queued but not running on it rq, we can simply migrate
it without migration thread and switching of context.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410519814.3569.7.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1) Nobody calls pick_dl_task() with negative cpu, it's old RT leftover.
2) If p->nr_cpus_allowed is 1, than the affinity has just been changed
in set_cpus_allowed_ptr(); we'll pick it just earlier than migration
thread.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1410529340.3569.27.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
new_cpu is reassigned below, so we do not need this here.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1410529276.3569.24.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The sig->stats_lock nests inside the tasklist_lock and the
sighand->siglock in __exit_signal and wait_task_zombie.
However, both of those locks can be taken from irq context,
which means we need to use the interrupt safe variant of
read_seqbegin_or_lock. This blocks interrupts when the "lock"
branch is taken (seq is odd), preventing the lock inversion.
On the first (lockless) pass through the loop, irqs are not
blocked.
Reported-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: prarit@redhat.com
Cc: oleg@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1410527535-9814-3-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently kick_all_cpus_sync() can break non-polling idle cpus
thru IPI interrupts.
But sometimes we need to break the polling idle cpus immediately
to reselect the suitable c-state, also for non-idle cpus, we need
to do nothing if we try to wake up them.
Here adding one new function wake_up_all_idle_cpus() to let all cpus
out of idle based on function wake_up_if_idle().
Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: daniel.lezcano@linaro.org
Cc: rjw@rjwysocki.net
Cc: linux-pm@vger.kernel.org
Cc: changcheng.liu@intel.com
Cc: xiaoming.wang@intel.com
Cc: souvik.k.chakravarty@intel.com
Cc: luto@amacapital.net
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@fb.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1409815075-4180-2-git-send-email-chuansheng.liu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The code in task_numa_compare() will only examine at most one idle CPU per node,
because they all have the same score. However, some idle CPUs are better
candidates than others, due to busy or idle SMT siblings, etc...
The scheduler has logic to find the best CPU within an LLC to place a
task. The NUMA code should probably use it.
This seems to reduce the standard deviation for single instance SPECjbb2005
with a low warehouse count on my 4 node test system.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: mgorman@suse.de
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140904163530.189d410a@cuia.bos.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently, the expedited grace-period primitives do get_online_cpus().
This greatly simplifies their implementation, but means that calls
to them holding locks that are acquired by CPU-hotplug notifiers (to
say nothing of calls to these primitives from CPU-hotplug notifiers)
can deadlock. But this is starting to become inconvenient, as can be
seen here: https://lkml.org/lkml/2014/8/5/754. The problem in this
case is that some developers need to acquire a mutex from a CPU-hotplug
notifier, but also need to hold it across a synchronize_rcu_expedited().
As noted above, this currently results in deadlock.
This commit avoids the deadlock and retains the simplicity by creating
a try_get_online_cpus(), which returns false if the get_online_cpus()
reference count could not immediately be incremented. If a call to
try_get_online_cpus() returns true, the expedited primitives operate as
before. If a call returns false, the expedited primitives fall back to
normal grace-period operations. This falling back of course results in
increased grace-period latency, but only during times when CPU hotplug
operations are actually in flight. The effect should therefore be
negligible during normal operation.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Tested-by: Lan Tianyu <tianyu.lan@intel.com>
Use the ONE macro instead of REG, and we can simplify proc_cpuset_show().
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Use the ONE macro instead of REG, and we can simplify proc_cgroup_show().
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Instead of using a global work to schedule release agent on removable
cgroups, we change to use a per-cgroup work to do this, which makes
the code much simpler.
v2: use a dedicated work instead of reusing css->destroy_work. (Tejun)
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
cgroup_pidlist_start() holds cgrp->pidlist_mutex and then calls
pidlist_array_load(), and cgroup_pidlist_stop() releases the mutex.
It is wrong that we release the mutex in the failure path in
pidlist_array_load(), because cgroup_pidlist_stop() will be called
no matter if cgroup_pidlist_start() returns errno or not.
Fixes: 4bac00d16a
Cc: <stable@vger.kernel.org> # 3.14+
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
We never grab cgroup mutex in fork and exit paths no matter whether
notify_on_release is set or not.
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We no longer clear kn->priv in cgroup_rmdir(), so we don't need
to get an extra refcnt.
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull to receive a4189487da ("cgroup: delay the clearing of
cgrp->kn->priv") for the scheduled clean up patches.
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit changes rcutorture_runnable to torture_runnable, which is
consistent with the names of the other parameters and is a bit shorter
as well.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The amount of global variables is getting pretty ugly. Group variables
related to the execution (ie: not parameters) in a new context structure.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
We can easily do so with our new reader lock support. Just an arbitrary
design default: readers have higher (5x) critical region latencies than
writers: 50 ms and 10 ms, respectively.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Most of it is based on what we already have for writers. This allows
readers to be very independent (and thus configurable), enabling
future module parameters to control things such as rw distribution.
Furthermore, readers have their own delaying function, allowing us
to test different rw critical region latencies, and stress locking
internals. Similarly, statistics, for now will only serve for the
number of lock acquisitions -- as opposed to writers, readers have
no failure detection.
In addition, introduce a new nreaders_stress module parameter. The
default number of readers will be the same number of writers threads.
Writer threads are interleaved with readers. Documentation is updated,
respectively.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
When performing module cleanups by calling torture_cleanup() the
'torture_type' string in nullified However, callers are not necessarily
done, and might still need to reference the variable. This impacts
both rcutorture and locktorture, causing printing things like:
[ 94.226618] (null)-torture: Stopping lock_torture_writer task
[ 94.226624] (null)-torture: Stopping lock_torture_stats task
Thus delay this operation until the very end of the cleanup process.
The consequence (which shouldn't matter for this kid of program) is,
of course, that we delay the window between rmmod and modprobing,
for instance in module_torture_begin().
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The statistics structure can serve well for both reader and writer
locks, thus simply rename some fields that mention 'write' and leave
the declaration of lwsa.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Regular locks are very different than locks with debugging. For instance
for mutexes, debugging forces to only take the slowpaths. As such, the
locktorture module should take this into account when printing related
information -- specifically when printing user passed parameters, it seems
the right place for such info.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add a "mutex_lock" torture test. The main difference with the already
existing spinlock tests is that the latency of the critical region
is much larger. We randomly delay for (arbitrarily) either 500 ms or,
otherwise, 25 ms. While this can considerably reduce the amount of
writes compared to non blocking locks, if run long enough it can have
the same torturous effect. Furthermore it is more representative of
mutex hold times and can stress better things like thrashing.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
... to just 'torture_runnable'. It follows other variable naming
and is shorter.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The NOCB follower wakeup ordering depends on the store to the tail
pointer happening before the wakeup. However, because atomic_long_add()
does not return a value, it does not provide ordering guarantees, and
the locking in wake_up() only guarantees that the store will happen
before the unlock, which might be too late. Even though this is only a
theoretical issue, this commit adds a smp_mb__after_atomic() after the
final atomic_long_add() to provide the needed ordering guarantee.
Reported-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
If an RCU callback is queued on a no-CBs CPU from idle code with irqs
disabled, and if that CPU stays idle forever after, the callback will
never be invoked. This commit therefore adds a check for this situation
in ____call_rcu_nocb(), invoking the RCU core solely for the purpose
of the ensuing return-to-idle transition. (If the CPU doesn't return
to idle, the next scheduling-clock interrupt will fix things up.)
Reported-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
The NOCB leader wakeup ordering depends on the store to the header
happening before the check for the leader already being awake. However,
because atomic_long_add() does not return a value, it does not provide
ordering guarantees, the incorrect comment in wake_nocb_leader()
notwithstanding. This commit therefore adds a smp_mb__after_atomic()
after the final atomic_long_add() to provide the needed ordering
guarantee.
Reported-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
If there are no nohz_full= CPUs, then there is currently no reason to
track sysidle state. This commit therefore short-circuits this state
tracking if !tick_nohz_full_enabled().
Note that these checks will need to be revisited if nohz_full= state
can ever be changed at runtime.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Now that we have rcu_state_p, which references rcu_preempt_state for
TREE_PREEMPT_RCU and rcu_sched_state for TREE_RCU, we don't need a
separate rcu_sysidle_state variable. This commit therefore eliminates
rcu_preempt_state in favor of rcu_state_p.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
If we configure a kernel with CONFIG_NOCB_CPU=y, CONFIG_RCU_NOCB_CPU_NONE=y and
CONFIG_CPUMASK_OFFSTACK=n and do not pass in a rcu_nocb= boot parameter, the
cpumask rcu_nocb_mask can be garbage instead of NULL.
Hence this commit replaces checks for rcu_nocb_mask == NULL with a check for
have_rcu_nocb_mask.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
RCU currently uses for_each_possible_cpu() to spawn rcuo kthreads,
which can result in more rcuo kthreads than one would expect, for
example, derRichard reported 64 CPUs worth of rcuo kthreads on an
8-CPU image. This commit therefore creates rcuo kthreads only for
those CPUs that actually come online.
This was reported by derRichard on the OFTC IRC network.
Reported-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Currently, RCU spawns kthreads from several different early_initcall()
functions. Although this has served RCU well for quite some time,
as more kthreads are added a more deterministic approach is required.
This commit therefore causes all of RCU's early-boot kthreads to be
spawned from a single early_initcall() function.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Return false instead of 0 in rcu_nocb_adopt_orphan_cbs() as this has
bool as return type.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Return false instead of 0 in __call_rcu_nocb() as this has bool as
return type.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Return true/false in rcu_nocb_adopt_orphan_cbs() instead of 0/1 as
this function has return type of bool.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Return true/false instead of 0/1 in __call_rcu_nocb() as this returns a
bool type.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
This commit checks the return value of the zalloc_cpumask_var() used for
allocating cpumask for rcu_nocb_mask.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Commit b58cc46c5f (rcu: Don't offload callbacks unless specifically
requested) failed to adjust the callback lists of the CPUs that are
known to be no-CBs CPUs only because they are also nohz_full= CPUs.
This failure can result in callbacks that are posted during early boot
getting stranded on nxtlist for CPUs whose no-CBs property becomes
apparent late, and there can also be spurious warnings about offline
CPUs posting callbacks.
This commit fixes these problems by adding an early-boot rcu_init_nohz()
that properly initializes the no-CBs CPUs.
Note that kernels built with CONFIG_RCU_NOCB_CPU_ALL=y or with
CONFIG_RCU_NOCB_CPU=n do not exhibit this bug. Neither do kernels
booted without the nohz_full= boot parameter.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Revert PERF_EVENT_STATE_EXIT check on read syscall path.
It breaks standard way to read counter, which is to open
the counter, wait for the monitored process to die and
read the counter.
Reported-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: David Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/20140908143107.GG17728@krava.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull futex and timer fixes from Thomas Gleixner:
"A oneliner bugfix for the jinxed futex code:
- Drop hash bucket lock in the error exit path. I really could slap
myself for intruducing that bug while fixing all the other horror
in that code three month ago ...
and the timer department is not too proud about the following fixes:
- Deal with a long standing rounding bug in the timeval to jiffies
conversion. It's a real issue and this fix fell through the cracks
for quite some time.
- Another round of alarmtimer fixes. Finally this code gets used
more widely and the subtle issues hidden for quite some time are
noticed and fixed. Nothing really exciting, just the itty bitty
details which bite the serious users here and there"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Unlock hb->lock in futex_wait_requeue_pi() error path
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
alarmtimer: Lock k_itimer during timer callback
alarmtimer: Do not signal SIGEV_NONE timers
alarmtimer: Return relative times in timer_gettime
jiffies: Fix timeval conversion to jiffies
The nohz full functionality depends on IRQ work to trigger its own
interrupts. As it's used to restart the tick, we can't rely on the tick
fallback for irq work callbacks, ie: we can't use the tick to restart
the tick itself.
Lets reject the full dynticks initialization if that arch support isn't
available.
As a side effect, this makes sure that nohz kick is never called from
the tick. That otherwise would result in illegal hrtimer self-cancellation
and lockup.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
The supports for CONFIG_NO_HZ_FULL_ALL=y and the nohz_full= kernel
parameter both have their own way to do the same thing: allocate
full dynticks cpumasks, fill them and initialize some state variables.
Lets consolidate that all in the same place.
While at it, convert some regular printk message to warnings when
fundamental allocations fail.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
The nohz full kick, which restarts the tick when any resource depend
on it, can't be executed anywhere given the operation it does on timers.
If it is called from the scheduler or timers code, chances are that
we run into a deadlock.
This is why we run the nohz full kick from an irq work. That way we make
sure that the kick runs on a virgin context.
However if that's the case when irq work runs in its own dedicated
self-ipi, things are different for the big bunch of archs that don't
support the self triggered way. In order to support them, irq works are
also handled by the timer interrupt as fallback.
Now when irq works run on the timer interrupt, the context isn't blank.
More precisely, they can run in the context of the hrtimer that runs the
tick. But the nohz kick cancels and restarts this hrtimer and cancelling
an hrtimer from itself isn't allowed. This is why we run in an endless
loop:
Kernel panic - not syncing: Watchdog detected hard LOCKUP on cpu 2
CPU: 2 PID: 7538 Comm: kworker/u8:8 Not tainted 3.16.0+ #34
Workqueue: btrfs-endio-write normal_work_helper [btrfs]
ffff880244c06c88 000000001b486fe1 ffff880244c06bf0 ffffffff8a7f1e37
ffffffff8ac52a18 ffff880244c06c78 ffffffff8a7ef928 0000000000000010
ffff880244c06c88 ffff880244c06c20 000000001b486fe1 0000000000000000
Call Trace:
<NMI[<ffffffff8a7f1e37>] dump_stack+0x4e/0x7a
[<ffffffff8a7ef928>] panic+0xd4/0x207
[<ffffffff8a1450e8>] watchdog_overflow_callback+0x118/0x120
[<ffffffff8a186b0e>] __perf_event_overflow+0xae/0x350
[<ffffffff8a184f80>] ? perf_event_task_disable+0xa0/0xa0
[<ffffffff8a01a4cf>] ? x86_perf_event_set_period+0xbf/0x150
[<ffffffff8a187934>] perf_event_overflow+0x14/0x20
[<ffffffff8a020386>] intel_pmu_handle_irq+0x206/0x410
[<ffffffff8a01937b>] perf_event_nmi_handler+0x2b/0x50
[<ffffffff8a007b72>] nmi_handle+0xd2/0x390
[<ffffffff8a007aa5>] ? nmi_handle+0x5/0x390
[<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0
[<ffffffff8a008062>] default_do_nmi+0x72/0x1c0
[<ffffffff8a008268>] do_nmi+0xb8/0x100
[<ffffffff8a7ff66a>] end_repeat_nmi+0x1e/0x2e
[<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0
[<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0
[<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0
<<EOE><IRQ[<ffffffff8a0ccd2f>] lock_acquired+0xaf/0x450
[<ffffffff8a0f74c5>] ? lock_hrtimer_base.isra.20+0x25/0x50
[<ffffffff8a7fc678>] _raw_spin_lock_irqsave+0x78/0x90
[<ffffffff8a0f74c5>] ? lock_hrtimer_base.isra.20+0x25/0x50
[<ffffffff8a0f74c5>] lock_hrtimer_base.isra.20+0x25/0x50
[<ffffffff8a0f7723>] hrtimer_try_to_cancel+0x33/0x1e0
[<ffffffff8a0f78ea>] hrtimer_cancel+0x1a/0x30
[<ffffffff8a109237>] tick_nohz_restart+0x17/0x90
[<ffffffff8a10a213>] __tick_nohz_full_check+0xc3/0x100
[<ffffffff8a10a25e>] nohz_full_kick_work_func+0xe/0x10
[<ffffffff8a17c884>] irq_work_run_list+0x44/0x70
[<ffffffff8a17c8da>] irq_work_run+0x2a/0x50
[<ffffffff8a0f700b>] update_process_times+0x5b/0x70
[<ffffffff8a109005>] tick_sched_handle.isra.21+0x25/0x60
[<ffffffff8a109b81>] tick_sched_timer+0x41/0x60
[<ffffffff8a0f7aa2>] __run_hrtimer+0x72/0x470
[<ffffffff8a109b40>] ? tick_sched_do_timer+0xb0/0xb0
[<ffffffff8a0f8707>] hrtimer_interrupt+0x117/0x270
[<ffffffff8a034357>] local_apic_timer_interrupt+0x37/0x60
[<ffffffff8a80010f>] smp_apic_timer_interrupt+0x3f/0x50
[<ffffffff8a7fe52f>] apic_timer_interrupt+0x6f/0x80
To fix this we force non-lazy irq works to run on irq work self-IPIs
when available. That ability of the arch to trigger irq work self IPIs
is available with arch_irq_work_has_interrupt().
Reported-by: Catalin Iacob <iacobcatalin@gmail.com>
Reported-by: Dave Jones <davej@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This way we unbloat a bit main.c and more importantly we initialize
nohz full after init_IRQ(). This dependency will be needed in further
patches because nohz full needs irq work to raise its own IRQ.
Information about the support for this ability on ARM64 is obtained on
init_IRQ() which initialize the pointer to __smp_call_function.
Since tick_init() is called right after init_IRQ(), this is a good place
to call tick_nohz_init() and prepare for that dependency.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
The ftrace_enabled variable is set to zero in the self tests to keep
delayed functions from being traced and messing with the checks. This
only needs to be done when the checks are being performed, otherwise,
if ftrace_enabled is off when calls back to the utility that is being
tested, it can cause errors to happen and the tests can fail with
false positives.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When the last ftrace_ops is unregistered, all the function records should
have a zeroed flags value. Make sure that is the case when the last ftrace_ops
is unregistered.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Locks the k_itimer's it_lock member when handling the alarm timer's
expiry callback.
The regular posix timers defined in posix-timers.c have this lock held
during timout processing because their callbacks are routed through
posix_timer_fn(). The alarm timers follow a different path, so they
ought to grab the lock somewhere else.
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: Richard Larocque <rlarocque@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Avoids sending a signal to alarm timers created with sigev_notify set to
SIGEV_NONE by checking for that special case in the timeout callback.
The regular posix timers avoid sending signals to SIGEV_NONE timers by
not scheduling any callbacks for them in the first place. Although it
would be possible to do something similar for alarm timers, it's simpler
to handle this as a special case in the timeout.
Prior to this patch, the alarm timer would ignore the sigev_notify value
and try to deliver signals to the process anyway. Even worse, the
sanity check for the value of sigev_signo is skipped when SIGEV_NONE was
specified, so the signal number could be bogus. If sigev_signo was an
unitialized value (as it often would be if SIGEV_NONE is used), then
it's hard to predict which signal will be sent.
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: Richard Larocque <rlarocque@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Returns the time remaining for an alarm timer, rather than the time at
which it is scheduled to expire. If the timer has already expired or it
is not currently scheduled, the it_value's members are set to zero.
This new behavior matches that of the other posix-timers and the POSIX
specifications.
This is a change in user-visible behavior, and may break existing
applications. Hopefully, few users rely on the old incorrect behavior.
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: Richard Larocque <rlarocque@google.com>
[jstultz: minor style tweak]
Signed-off-by: John Stultz <john.stultz@linaro.org>
timeval_to_jiffies tried to round a timeval up to an integral number
of jiffies, but the logic for doing so was incorrect: intervals
corresponding to exactly N jiffies would become N+1. This manifested
itself particularly repeatedly stopping/starting an itimer:
setitimer(ITIMER_PROF, &val, NULL);
setitimer(ITIMER_PROF, NULL, &val);
would add a full tick to val, _even if it was exactly representable in
terms of jiffies_ (say, the result of a previous rounding.) Doing
this repeatedly would cause unbounded growth in val. So fix the math.
Here's what was wrong with the conversion: we essentially computed
(eliding seconds)
jiffies = usec * (NSEC_PER_USEC/TICK_NSEC)
by using scaling arithmetic, which took the best approximation of
NSEC_PER_USEC/TICK_NSEC with denominator of 2^USEC_JIFFIE_SC =
x/(2^USEC_JIFFIE_SC), and computed:
jiffies = (usec * x) >> USEC_JIFFIE_SC
and rounded this calculation up in the intermediate form (since we
can't necessarily exactly represent TICK_NSEC in usec.) But the
scaling arithmetic is a (very slight) *over*approximation of the true
value; that is, instead of dividing by (1 usec/ 1 jiffie), we
effectively divided by (1 usec/1 jiffie)-epsilon (rounding
down). This would normally be fine, but we want to round timeouts up,
and we did so by adding 2^USEC_JIFFIE_SC - 1 before the shift; this
would be fine if our division was exact, but dividing this by the
slightly smaller factor was equivalent to adding just _over_ 1 to the
final result (instead of just _under_ 1, as desired.)
In particular, with HZ=1000, we consistently computed that 10000 usec
was 11 jiffies; the same was true for any exact multiple of
TICK_NSEC.
We could possibly still round in the intermediate form, adding
something less than 2^USEC_JIFFIE_SC - 1, but easier still is to
convert usec->nsec, round in nanoseconds, and then convert using
time*spec*_to_jiffies. This adds one constant multiplication, and is
not observably slower in microbenchmarks on recent x86 hardware.
Tested: the following program:
int main() {
struct itimerval zero = {{0, 0}, {0, 0}};
/* Initially set to 10 ms. */
struct itimerval initial = zero;
initial.it_interval.tv_usec = 10000;
setitimer(ITIMER_PROF, &initial, NULL);
/* Save and restore several times. */
for (size_t i = 0; i < 10; ++i) {
struct itimerval prev;
setitimer(ITIMER_PROF, &zero, &prev);
/* on old kernels, this goes up by TICK_USEC every iteration */
printf("previous value: %ld %ld %ld %ld\n",
prev.it_interval.tv_sec, prev.it_interval.tv_usec,
prev.it_value.tv_sec, prev.it_value.tv_usec);
setitimer(ITIMER_PROF, &prev, NULL);
}
return 0;
}
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Turner <pjt@google.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Reviewed-by: Paul Turner <pjt@google.com>
Reported-by: Aaron Jacobs <jacobsa@google.com>
Signed-off-by: Andrew Hunter <ahh@google.com>
[jstultz: Tweaked to apply to 3.17-rc]
Signed-off-by: John Stultz <john.stultz@linaro.org>
futex_wait_requeue_pi() calls futex_wait_setup(). If
futex_wait_setup() succeeds it returns with hb->lock held and
preemption disabled. Now the sanity check after this does:
if (match_futex(&q.key, &key2)) {
ret = -EINVAL;
goto out_put_keys;
}
which releases the keys but does not release hb->lock.
So we happily return to user space with hb->lock held and therefor
preemption disabled.
Unlock hb->lock before taking the exit route.
Reported-by: Dave "Trinity" Jones <davej@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Darren Hart <dvhart@linux.intel.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1409112318500.4178@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The C operator <= defines a perfectly fine total ordering on the set of
values representable in a long. However, unlike its namesake in the
integers, it is not translation invariant, meaning that we do not have
"b <= c" iff "a+b <= a+c" for all a,b,c.
This means that it is always wrong to try to boil down the relationship
between two longs to a question about the sign of their difference,
because the resulting relation [a LEQ b iff a-b <= 0] is neither
anti-symmetric or transitive. The former is due to -LONG_MIN==LONG_MIN
(take any two a,b with a-b = LONG_MIN; then a LEQ b and b LEQ a, but a !=
b). The latter can either be seen observing that x LEQ x+1 for all x,
implying x LEQ x+1 LEQ x+2 ... LEQ x-1 LEQ x; or more directly with the
simple example a=LONG_MIN, b=0, c=1, for which a-b < 0, b-c < 0, but a-c >
0.
Note that it makes absolutely no difference that a transmogrying bijection
has been applied before the comparison is done. In fact, had the
obfuscation not been done, one could probably not observe the bug
(assuming all values being compared always lie in one half of the address
space, the mathematical value of a-b is always representable in a long).
As it stands, one can easily obtain three file descriptors exhibiting the
non-transitivity of kcmp().
Side note 1: I can't see that ensuring the MSB of the multiplier is
set serves any purpose other than obfuscating the obfuscating code.
Side note 2:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <assert.h>
#include <sys/syscall.h>
enum kcmp_type {
KCMP_FILE,
KCMP_VM,
KCMP_FILES,
KCMP_FS,
KCMP_SIGHAND,
KCMP_IO,
KCMP_SYSVSEM,
KCMP_TYPES,
};
pid_t pid;
int kcmp(pid_t pid1, pid_t pid2, int type,
unsigned long idx1, unsigned long idx2)
{
return syscall(SYS_kcmp, pid1, pid2, type, idx1, idx2);
}
int cmp_fd(int fd1, int fd2)
{
int c = kcmp(pid, pid, KCMP_FILE, fd1, fd2);
if (c < 0) {
perror("kcmp");
exit(1);
}
assert(0 <= c && c < 3);
return c;
}
int cmp_fdp(const void *a, const void *b)
{
static const int normalize[] = {0, -1, 1};
return normalize[cmp_fd(*(int*)a, *(int*)b)];
}
#define MAX 100 /* This is plenty; I've seen it trigger for MAX==3 */
int main(int argc, char *argv[])
{
int r, s, count = 0;
int REL[3] = {0,0,0};
int fd[MAX];
pid = getpid();
while (count < MAX) {
r = open("/dev/null", O_RDONLY);
if (r < 0)
break;
fd[count++] = r;
}
printf("opened %d file descriptors\n", count);
for (r = 0; r < count; ++r) {
for (s = r+1; s < count; ++s) {
REL[cmp_fd(fd[r], fd[s])]++;
}
}
printf("== %d\t< %d\t> %d\n", REL[0], REL[1], REL[2]);
qsort(fd, count, sizeof(fd[0]), cmp_fdp);
memset(REL, 0, sizeof(REL));
for (r = 0; r < count; ++r) {
for (s = r+1; s < count; ++s) {
REL[cmp_fd(fd[r], fd[s])]++;
}
}
printf("== %d\t< %d\t> %d\n", REL[0], REL[1], REL[2]);
return (REL[0] + REL[2] != 0);
}
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
"Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We shouldn't set text_len in the code path that detects printk recursion
because text_len corresponds to the length of the string inside textbuf.
A few lines down from the line
text_len = strlen(recursion_msg);
is the line
text_len += vscnprintf(text + text_len, ...);
So if printk detects recursion, it sets text_len to 29 (the length of
recursion_msg) and logs an error. Then the message supplied by the
caller of printk is stored inside textbuf but offset by 29 bytes. This
means that the output of the recursive call to printk will contain 29
bytes of garbage in front of it.
This defect is caused by commit 458df9fd48 ("printk: remove separate
printk_sched buffers and use printk buf instead") which turned the line
text_len = vscnprintf(text, ...);
into
text_len += vscnprintf(text + text_len, ...);
To fix this, this patch avoids setting text_len when logging the printk
recursion error. This patch also marks unlikely() the branch leading up
to this code.
Fixes: 458df9fd48 ("printk: remove separate printk_sched buffers and use printk buf instead")
Signed-off-by: Patrick Palka <patrick@parcs.ath.cx>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since BPF JIT depends on the availability of module_alloc() and
module_free() helpers (HAVE_BPF_JIT and MODULES), we better build
that code only in case we have BPF_JIT in our config enabled, just
like with other JIT code. Fixes builds for arm/marzen_defconfig
and sh/rsk7269_defconfig.
====================
kernel/built-in.o: In function `bpf_jit_binary_alloc':
/home/cwang/linux/kernel/bpf/core.c:144: undefined reference to `module_alloc'
kernel/built-in.o: In function `bpf_jit_binary_free':
/home/cwang/linux/kernel/bpf/core.c:164: undefined reference to `module_free'
make: *** [vmlinux] Error 1
====================
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Fixes: 738cbe72ad ("net: bpf: consolidate JIT binary allocator")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The uses of "rcu_assign_pointer()" are NULLing out the pointers.
According to RCU_INIT_POINTER()'s block comment:
"1. This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a
smaller overhead.
The following Coccinelle semantic patch was used:
@@
@@
- rcu_assign_pointer
+ RCU_INIT_POINTER
(..., NULL)
Link: http://lkml.kernel.org/p/20140822142822.GA32391@ada
Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Allowing function callbacks to declare their own trampolines requires
that each ftrace_ops that has a trampoline must have some sort of
accounting that keeps track of which ops has a trampoline attached
to a record.
The easy way to solve this was to add a "tramp_hash" that created a
hash entry for every function that a ops uses with a trampoline.
But since we can have literally tens of thousands of functions being
traced, that means we need tens of thousands of descriptors to map
the ops to the function in the hash. This is quite expensive and
can cause enabling and disabling the function graph tracer to take
some time to start and stop. It can take up to several seconds to
disable or enable all functions in the function graph tracer for this
reason.
The better approach albeit more complex, is to keep track of how ops
are being enabled and disabled, and use that along with the counting
of the number of ops attached to records, to determive what ops has
a trampoline attached to a record at enabling and disabling of
tracing.
To do this, the tramp_hash has been replaced with an old_filter_hash
and old_notrace_hash, which get the copy of the ops filter_hash and
notrace_hash respectively. The old hashes is kept until the ops has
been modified or removed and the old hashes are used with the logic
of the accounting to determine the ops that have the trampoline of
a record. The reason this has less of a footprint is due to the trick
that an "empty" hash in the filter_hash means "all functions" and
an empty hash in the notrace hash means "no functions" in the hash.
This is much more efficienct, doesn't have the delay, and takes up
much less memory, as we do not need to map all the functions but
just figure out which functions are mapped at the time it is
enabled or disabled.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add three new flags for ftrace_ops:
FTRACE_OPS_FL_ADDING
FTRACE_OPS_FL_REMOVING
FTRACE_OPS_FL_MODIFYING
These will be set for the ftrace_ops when they are first added
to the function tracing, being removed from function tracing
or just having their functions changed from function tracing,
respectively.
This will be needed to remove the tramp_hash, which can grow quite
big. The tramp_hash is used to note what functions a ftrace_ops
is using a trampoline for. Denoting which ftrace_ops is being
modified, will allow us to use the ftrace_ops hashes themselves,
which are much smaller as they have a global flag to denote if
a ftrace_ops is tracing all functions, as well as a notrace hash
if the ftrace_ops is tracing all but a few. The tramp_hash just
creates a hash item for every function, which can go into the 10s
of thousands if all functions are using the ftrace_ops trampoline.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When dumping the enabled_functions, use the first op that is
found with a trampoline to the record, as there should only be
one, as only one ops can be registered to a function that has
a trampoline.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
ftrace_hash_move() currently frees the old hash that is passed to it
after replacing the pointer with the new hash. Instead of having the
function do that chore, have the caller perform the free.
This lets the ftrace_hash_move() be used a bit more freely, which
is needed for changing the way the trampoline logic is done.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The clean up that adds the helper function ftrace_ops_get_func()
caused the default function to not change when DYNAMIC_FTRACE was not
set and no ftrace_ops were registered. Although static tracing is
not very useful (not having DYNAMIC_FTRACE set), it is still supported
and we don't want to break it.
Clean up the if statement even more to specifically have the default
function call ftrace_stub when no ftrace_ops are registered. This
fixes the small bug for static tracing as well as makes the code a
bit more understandable.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Introduced in commit 314beb9bca ("x86: bpf_jit_comp: secure bpf jit
against spraying attacks") and later on replicated in aa2d2c73c2
("s390/bpf,jit: address randomize and write protect jit code") for
s390 architecture, write protection for BPF JIT images got added and
a random start address of the JIT code, so that it's not on a page
boundary anymore.
Since both use a very similar allocator for the BPF binary header,
we can consolidate this code into the BPF core as it's mostly JIT
independant anyway.
This will also allow for future archs that support DEBUG_SET_MODULE_RONX
to just reuse instead of reimplementing it.
JIT tested on x86_64 and s390x with BPF test suite.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add the helper function to what the mcount trampoline is to call
for a ftrace_ops function. This helper will be used by arch code
in the future to set up dynamic trampolines. But as this does the
same tests that are performed in choosing what function to call for
the default mcount trampoline, might as well use it to clean up
the existing code.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
add BPF_LD_IMM64 instruction to load 64-bit immediate value into a register.
All previous instructions were 8-byte. This is first 16-byte instruction.
Two consecutive 'struct bpf_insn' blocks are interpreted as single instruction:
insn[0].code = BPF_LD | BPF_DW | BPF_IMM
insn[0].dst_reg = destination register
insn[0].imm = lower 32-bit
insn[1].code = 0
insn[1].imm = upper 32-bit
All unused fields must be zero.
Classic BPF has similar instruction: BPF_LD | BPF_W | BPF_IMM
which loads 32-bit immediate value into a register.
x64 JITs it as single 'movabsq %rax, imm64'
arm64 may JIT as sequence of four 'movk x0, #imm16, lsl #shift' insn
Note that old eBPF programs are binary compatible with new interpreter.
It helps eBPF programs load 64-bit constant into a register with one
instruction instead of using two registers and 4 instructions:
BPF_MOV32_IMM(R1, imm32)
BPF_ALU64_IMM(BPF_LSH, R1, 32)
BPF_MOV32_IMM(R2, imm32)
BPF_ALU64_REG(BPF_OR, R1, R2)
User space generated programs will use this instruction to load constants only.
To tell kernel that user space needs a pointer the _pseudo_ variant of
this instruction may be added later, which will use extra bits of encoding
to indicate what type of pointer user space is asking kernel to provide.
For example 'off' or 'src_reg' fields can be used for such purpose.
src_reg = 1 could mean that user space is asking kernel to validate and
load in-kernel map pointer.
src_reg = 2 could mean that user space needs readonly data section pointer
src_reg = 3 could mean that user space needs a pointer to per-cpu local data
All such future pseudo instructions will not be carrying the actual pointer
as part of the instruction, but rather will be treated as a request to kernel
to provide one. The kernel will verify the request_for_a_pointer, then
will drop _pseudo_ marking and will store actual internal pointer inside
the instruction, so the end result is the interpreter and JITs never
see pseudo BPF_LD_IMM64 insns and only operate on generic BPF_LD_IMM64 that
loads 64-bit immediate into a register. User space never operates on direct
pointers and verifier can easily recognize request_for_pointer vs other
instructions.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of using the generic list function for callbacks that
are not recursive, call a new helper function from the mcount
trampoline called ftrace_ops_recur_func() that will do the recursion
checking for the callback.
This eliminates an indirection as well as will help in future code
that will use dynamically allocated trampolines.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch fix spelling typo found in DocBook/kernel-api.xml.
It is because the file is generated from the source comments,
I have to fix the comments in source codes.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
We saw a kernel soft lockup in perf_remove_from_context(),
it looks like the `perf` process, when exiting, could not go
out of the retry loop. Meanwhile, the target process was forking
a child. So either the target process should execute the smp
function call to deactive the event (if it was running) or it should
do a context switch which deactives the event.
It seems we optimize out a context switch in perf_event_context_sched_out(),
and what's more important, we still test an obsolete task pointer when
retrying, so no one actually would deactive that event in this situation.
Fix it directly by reloading the task pointer in perf_remove_from_context().
This should cure the above soft lockup.
Signed-off-by: Cong Wang <cwang@twopensource.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1409696840-843-1-git-send-email-xiyou.wangcong@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The use of "rcu_assign_pointer()" is NULLing out the pointer.
According to RCU_INIT_POINTER()'s block comment:
"1. This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a
smaller overhead.
The following Coccinelle semantic patch was used:
@@
@@
- rcu_assign_pointer
+ RCU_INIT_POINTER
(..., NULL)
Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: http://lkml.kernel.org/r/20140822132605.GA20130@ada
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The use of "rcu_assign_pointer()" is NULLing out the pointer.
According to RCU_INIT_POINTER()'s block comment:
"1. This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a
smaller overhead.
The following Coccinelle semantic patch was used:
@@
@@
- rcu_assign_pointer
+ RCU_INIT_POINTER
(..., NULL)
Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: paulmck@linux.vnet.ibm.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: http://lkml.kernel.org/r/20140822141536.GA32051@ada
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When running workloads on 2+ socket systems, based on perf profiles, the
update_cfs_rq_blocked_load() function often shows up as taking up a
noticeable % of run time.
Much of the contention is in __update_cfs_rq_tg_load_contrib() when we
update the tg load contribution stats. However, it turns out that in many
cases, they don't need to be updated and "tg_contrib" is 0.
This patch adds a check in __update_cfs_rq_tg_load_contrib() to skip updating
tg load contribution stats when nothing needs to be updated. This reduces the
cacheline contention that would be unnecessary.
Reviewed-by: Ben Segall <bsegall@google.com>
Reviewed-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: jason.low2@hp.com
Cc: Yuyang Du <yuyang.du@intel.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409643684.19197.15.camel@j-VirtualBox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Current code can fail to migrate a waking task (silently) when TTWU_QUEUE is
enabled.
When a task is waking, it is pending on the wake_list of the rq, but it is not
queued (task->on_rq == 0). In this case, set_cpus_allowed_ptr() and
__migrate_task() will not migrate it because its invisible to them.
This behavior is incorrect, because the task has been already woken, it will be
running on the wrong CPU without correct placement until the next wake-up or
update for cpus_allowed.
To fix this problem, we need to finish the wakeup (so they appear on
the runqueue) before we migrate them.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Reported-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Tested-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/538ED7EB.5050303@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Enhanced test_suspend boot paramter to repeat tests multiple times,
by adding optional repeat count. The new boot param syntax:
test_suspend="mem|freeze|standby[,N]"
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Added freeze as one of the option for test_suspend boot param.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The functions task_cputime_adjusted and thread_group_cputime_adjusted()
can be called locklessly, as well as concurrently on many different CPUs.
This can occasionally lead to the utime and stime reported by times(), and
other syscalls like it, going backward. The cause for this appears to be
multiple threads racing in cputime_adjust(), both with values for utime or
stime that is larger than the original, but each with a different value.
Sometimes the larger value gets saved first, only to be immediately
overwritten with a smaller value by another thread.
Using atomic exchange prevents that problem, and ensures time
progresses monotonically.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: umgwanakikbuti@gmail.com
Cc: fweisbec@gmail.com
Cc: akpm@linux-foundation.org
Cc: srao@redhat.com
Cc: lwoodman@redhat.com
Cc: atheurer@redhat.com
Cc: oleg@redhat.com
Link: http://lkml.kernel.org/r/1408133138-22048-4-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Both times() and clock_gettime(CLOCK_PROCESS_CPUTIME_ID) have scalability
issues on large systems, due to both functions being serialized with a
lock.
The lock protects against reporting a wrong value, due to a thread in the
task group exiting, its statistics reporting up to the signal struct, and
that exited task's statistics being counted twice (or not at all).
Protecting that with a lock results in times() and clock_gettime() being
completely serialized on large systems.
This can be fixed by using a seqlock around the events that gather and
propagate statistics. As an additional benefit, the protection code can
be moved into thread_group_cputime(), slightly simplifying the calling
functions.
In the case of posix_cpu_clock_get_task() things can be simplified a
lot, because the calling function already ensures that the task sticks
around, and the rest is now taken care of in thread_group_cputime().
This way the statistics reporting code can run lockless.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Daeseok Youn <daeseok.youn@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guillaume Morin <guillaume@morinfr.org>
Cc: Ionut Alexa <ionut.m.alexa@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Michal Schmidt <mschmidt@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: umgwanakikbuti@gmail.com
Cc: fweisbec@gmail.com
Cc: srao@redhat.com
Cc: lwoodman@redhat.com
Cc: atheurer@redhat.com
Link: http://lkml.kernel.org/r/20140816134010.26a9b572@annuminas.surriel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Oleg pointed out that wait_task_zombie adds a task's usage statistics
to the parent's signal struct, but the task's own signal struct should
also propagate the statistics at exit time.
This allows thread_group_cputime(reaped_zombie) to get the statistics
after __unhash_process() has made the task invisible to for_each_thread,
but before the thread has actually been rcu freed, making sure no
non-monotonic results are returned inside that window.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Guillaume Morin <guillaume@morinfr.org>
Cc: Ionut Alexa <ionut.m.alexa@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Michal Schmidt <mschmidt@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: umgwanakikbuti@gmail.com
Cc: fweisbec@gmail.com
Cc: srao@redhat.com
Cc: lwoodman@redhat.com
Cc: atheurer@redhat.com
Link: http://lkml.kernel.org/r/1408133138-22048-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'v3.17-rc4' into sched/core, to prevent conflicts with upcoming patches, and to refresh the tree
Linux 3.17-rc4
Pull cgroup fixes from Tejun Heo:
"This pull request includes Alban's patch to disallow '\n' in cgroup
names.
Two other patches from Li to fix a possible oops when cgroup
destruction races against other file operations and one from Vivek to
fix a unified hierarchy devel behavior"
* 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: check cgroup liveliness before unbreaking kernfs
cgroup: delay the clearing of cgrp->kn->priv
cgroup: Display legacy cgroup files on default hierarchy
cgroup: reject cgroup names with '\n'
Percpu allocator now supports allocation mask. Add @gfp to
percpu_ref_init() so that !GFP_KERNEL allocation masks can be used
with percpu_refs too.
This patch doesn't make any functional difference.
v2: blk-mq conversion was missing. Updated.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Cc: Jens Axboe <axboe@kernel.dk>
The rcu_bh_qs(), rcu_preempt_qs(), and rcu_sched_qs() functions use
old-style per-CPU variable access and write to ->passed_quiesce even
if it is already set. This commit therefore updates to use the new-style
per-CPU variable access functions and avoids the spurious writes.
This commit also eliminates the "cpu" argument to these functions because
they are always invoked on the indicated CPU.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_preempt_note_context_switch() function is on a scheduling fast
path, so it would be good to avoid disabling irqs. The reason that irqs
are disabled is to synchronize process-level and irq-handler access to
the task_struct ->rcu_read_unlock_special bitmask. This commit therefore
makes ->rcu_read_unlock_special instead be a union of bools with a short
allowing single-access checks in RCU's __rcu_read_unlock(). This results
in the process-level and irq-handler accesses being simple loads and
stores, so that irqs need no longer be disabled. This commit therefore
removes the irq disabling from rcu_preempt_note_context_switch().
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The grace-period-wait loop in rcu_tasks_kthread() is under (unnecessary)
RCU protection, and therefore has no preemption points in a PREEMPT=n
kernel. This commit therefore removes the RCU protection and inserts
cond_resched().
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently TASKS_RCU would ignore a CPU running a task in nohz_full=
usermode execution. There would be neither a context switch nor a
scheduling-clock interrupt to tell TASKS_RCU that the task in question
had passed through a quiescent state. The grace period would therefore
extend indefinitely. This commit therefore makes RCU's dyntick-idle
subsystem record the task_struct structure of the task that is running
in dyntick-idle mode on each CPU. The TASKS_RCU grace period can
then access this information and record a quiescent state on
behalf of any CPU running in dyntick-idle usermode.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
It is expected that many sites will have CONFIG_TASKS_RCU=y, but
will never actually invoke call_rcu_tasks(). For such sites, creating
rcu_tasks_kthread() at boot is wasteful. This commit therefore defers
creation of this kthread until the time of the first call_rcu_tasks().
This of course means that the first call_rcu_tasks() must be invoked
from process context after the scheduler is fully operational.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The current RCU-tasks implementation uses strict polling to detect
callback arrivals. This works quite well, but is not so good for
energy efficiency. This commit therefore replaces the strict polling
with a wait queue.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit adds a ten-minute RCU-tasks stall warning. The actual
time is controlled by the boot/sysfs parameter rcu_task_stall_timeout,
with values less than or equal to zero disabling the stall warnings.
The default value is ten minutes, which means that the tasks that have
not yet responded will get their stacks dumped every ten minutes, until
they pass through a voluntary context switch.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit adds torture tests for RCU-tasks. It also fixes a bug that
would segfault for an RCU flavor lacking a callback-barrier function.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit exports the RCU-tasks synchronous APIs,
synchronize_rcu_tasks() and rcu_barrier_tasks(), to
GPL-licensed kernel modules.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Once a task has passed exit_notify() in the do_exit() code path, it
is no longer on the task lists, and is therefore no longer visible
to rcu_tasks_kthread(). This means that an almost-exited task might
be preempted while within a trampoline, and this task won't be waited
on by rcu_tasks_kthread(). This commit fixes this bug by adding an
srcu_struct. An exiting task does srcu_read_lock() just before calling
exit_notify(), and does the corresponding srcu_read_unlock() after
doing the final preempt_disable(). This means that rcu_tasks_kthread()
can do synchronize_srcu() to wait for all mostly-exited tasks to reach
their final preempt_disable() region, and then use synchronize_sched()
to wait for those tasks to finish exiting.
Reported-by: Oleg Nesterov <oleg@redhat.com>
Suggested-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
It turns out to be easier to add the synchronous grace-period waiting
functions to RCU-tasks than to work around their absense in rcutorture,
so this commit adds them. The key point is that the existence of
call_rcu_tasks() means that rcutorture needs an rcu_barrier_tasks().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
RCU-tasks requires the occasional voluntary context switch
from CPU-bound in-kernel tasks. In some cases, this requires
instrumenting cond_resched(). However, there is some reluctance
to countenance unconditionally instrumenting cond_resched() (see
http://lwn.net/Articles/603252/), so this commit creates a separate
cond_resched_rcu_qs() that may be used in place of cond_resched() in
locations prone to long-duration in-kernel looping.
This commit currently instruments only RCU-tasks. Future possibilities
include also instrumenting RCU, RCU-bh, and RCU-sched in order to reduce
IPI usage.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit adds a new RCU-tasks flavor of RCU, which provides
call_rcu_tasks(). This RCU flavor's quiescent states are voluntary
context switch (not preemption!) and userspace execution (not the idle
loop -- use some sort of schedule_on_each_cpu() if you need to handle the
idle tasks. Note that unlike other RCU flavors, these quiescent states
occur in tasks, not necessarily CPUs. Includes fixes from Steven Rostedt.
This RCU flavor is assumed to have very infrequent latency-tolerant
updaters. This assumption permits significant simplifications, including
a single global callback list protected by a single global lock, along
with a single task-private linked list containing all tasks that have not
yet passed through a quiescent state. If experience shows this assumption
to be incorrect, the required additional complexity will be added.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Although RCU is designed to handle arbitrary floods of callbacks, this
capability is not routinely tested. This commit therefore adds a
cbflood capability in which kthreads repeatedly registers large numbers
of callbacks. One such kthread is created for each four CPUs (rounding
up), and the test may be controlled by several cbflood_* kernel boot
parameters, which control the number of bursts per flood, the number
of callbacks per burst, the time between bursts, and the time between
floods. The default values are large enough to exercise RCU's emergency
responses to callback flooding.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: David Miller <davem@davemloft.net>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
User pr_alert/pr_cont for printing the logs from rcutorture module directly
instead of writing it to a buffer and then printing it. This allows us from not
having to allocate such buffers. Also remove a resulting empty function.
I tested this using the parse-torture.sh script as follows:
$ dmesg | grep torture > log.txt
$ bash parse-torture.sh log.txt test
$
There were no warnings which means that parsing went fine.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit fixes the following sparse warning by marking boost_mutex
static:
kernel/rcu/rcutorture.c:185:1: warning: symbol 'boost_mutex' was not declared. Should it be static?
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Currently, when RCU awakens from a wait_event_interruptible() that
might have awakened prematurely, it does a flush_signals(). This is
done on the off-chance that someone figured out how to deliver a signal
to a kthread, which is supposed to be impossible. Given that this
is supposed to be impossible, this commit changes the flush_signals()
calls into WARN_ON(signal_pending()).
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_gp_kthread_wake() function checks for three conditions before
waking up grace period kthreads:
* Is the thread we are trying to wake up the current thread?
* Are the gp_flags zero? (all threads wait on non-zero gp_flags condition)
* Is there no thread created for this flavour, hence nothing to wake up?
If any one of these condition is true, we do not call wake_up().
It was found that there are quite a few avoidable wake ups both during
idle time and under stress induced by rcutorture.
Idle:
Total:66000, unnecessary:66000, case1:61827, case2:66000, case3:0
Total:68000, unnecessary:68000, case1:63696, case2:68000, case3:0
rcutorture:
Total:254000, unnecessary:254000, case1:199913, case2:254000, case3:0
Total:256000, unnecessary:256000, case1:201784, case2:256000, case3:0
Here case{1-3} are the cases listed above. We can avoid these wake
ups by using rcu_gp_kthread_wake() to conditionally wake up the grace
period kthreads.
There is a comment about an implied barrier supplied by the wake_up()
logic. This barrier is necessary for the awakened thread to see the
updated ->gp_flags. This flag is always being updated with the root node
lock held. Also, the awakened thread tries to acquire the root node lock
before reading ->gp_flags because of which there is proper ordering.
Hence this commit tries to avoid calling wake_up() whenever we can by
using rcu_gp_kthread_wake() function.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
CC: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_idle_enter_common() and rcu_idle_exit_common() functions contain
error checks that have to the best of my knowledge have never triggered
over the past several years. These are nevertheless valuable when
creating new architectures or doing other low-level changes, so the
checks should not be deleted. This commit instead places these checks
under #ifdef CONFIG_RCU_TRACE so that they are executed only when
specifically requested.
The savings are significant:
Before:
text data bss dec hex filename
1749 39 0 1788 6fc /tmp/b/kernel/rcu/tiny.o
632 152 0 784 310 /tmp/b/kernel/rcu/update.o
----
2572
After:
text data bss dec hex filename
1281 37 0 1318 526 /tmp/b/kernel/rcu/tiny.o
632 152 0 784 310 /tmp/b/kernel/rcu/update.o
----
2102
This amounts to 470 bytes, or 18% of the original.
Switched from #ifdef to IS_ENABLED() on Josh Triplett's advice.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Commit 96d3fd0d31 (rcu: Break call_rcu() deadlock involving scheduler
and perf) covered the case where __call_rcu_nocb_enqueue() needs to wake
the rcuo kthread due to the queue being initially empty, but did not
do anything for the case where the queue was overflowing. This commit
therefore also defers wakeup for the overflow case.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes a stale comment in rcu/tree.c which was left
out when some code was moved around previously in commit 2036d94a7b
("rcu: Rework detection of use of RCU by offline CPUs") For reference,
the following updated comment exists a few lines below this which means
the same:
/* Remove the outgoing CPU from the masks in the rcu_node hierarchy. */
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit updates the references to rcutree.c which is now rcu/tree.c
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Commit f7f7bac9cb ("rcu: Have the RCU tracepoints use the tracepoint_string
infrastructure") unconditionally populates the __tracepoint_str input section,
but this section is not assigned an output section if CONFIG_TRACING is not set.
This results in the __tracepoint_str turning up in unexpected places, i.e.,
after _edata.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit uninlines rcu_read_lock_held(). According to "size vmlinux"
this saves 28549 in .text:
- 5541731 3014560 14757888 23314179
+ 5513182 3026848 14757888 23297918
Note: it looks as if the data grows by 12288 bytes but this is not true,
it does not actually grow. But .data starts with ALIGN(THREAD_SIZE) and
since .text shrinks the padding grows, and thus .data grows too as it
seen by /bin/size. diff System.map:
- ffffffff81510000 D _sdata
- ffffffff81510000 D init_thread_union
+ ffffffff81509000 D _sdata
+ ffffffff8150c000 D init_thread_union
Perhaps we can change vmlinux.lds.S to .data itself, so that /bin/size
can't "wrongly" report that .data grows if .text shinks.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit uses true/false instead of 1/0 for bool types in rcu_gp_fqs()
and force_qs_rnp().
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Return a bool type instead of 0 in rcu_try_advance_all_cbs().
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Use a bool type for return in rcu_is_watching().
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
fix sparse warning about rcu_batches_completed_preempt() being non-static by
marking it as static
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Change the remaining uses of ACCESS_ONCE() so that each ACCESS_ONCE() either does a load or a store, but not both.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
- Fix for recently broken test_suspend= command line argument
(Rafael J Wysocki).
- Fixes for regressions related to the ACPI video driver caused
by switching the default to native backlight handling in 3.16
from Hans de Goede.
- Fix for a sysfs attribute of ACPI device objects that returns
stale values sometimes due to the fact that they are cached
instead of executing the appropriate method (_SUN) every time
(broken in 3.14). From Yasuaki Ishimatsu.
- Fix for a deadlock between cpuidle_lock and cpu_hotplug.lock
in the ACPI processor driver from Jiri Kosina.
- Runtime output validation for the ACPI _DSD device configuration
object missing from the support for it that has been introduced
recently. From Mika Westerberg.
- Fix for an unuseful and misleading RAPL (Running Average Power
Limit) domain detection message in the RAPL driver from Jacob Pan.
- New Intel Haswell CPU ID for the RAPL driver from Jason Baron.
- New Clevo W350etq blacklist entry for the ACPI EC driver
from Lan Tianyu.
- Cleanup for the intel_pstate driver and the core generic PM
domains code from Gabriele Mazzotta and Geert Uytterhoeven.
/
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Merge tag 'pm+acpi-3.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management fixes from Rafael Wysocki:
"These are regression fixes (ACPI sysfs, ACPI video, suspend test),
ACPI cpuidle deadlock fix, missing runtime validation of ACPI _DSD
output, a fix and a new CPU ID for the RAPL driver, new blacklist
entry for the ACPI EC driver and a couple of trivial cleanups
(intel_pstate and generic PM domains).
Specifics:
- Fix for recently broken test_suspend= command line argument (Rafael
Wysocki).
- Fixes for regressions related to the ACPI video driver caused by
switching the default to native backlight handling in 3.16 from
Hans de Goede.
- Fix for a sysfs attribute of ACPI device objects that returns stale
values sometimes due to the fact that they are cached instead of
executing the appropriate method (_SUN) every time (broken in
3.14). From Yasuaki Ishimatsu.
- Fix for a deadlock between cpuidle_lock and cpu_hotplug.lock in the
ACPI processor driver from Jiri Kosina.
- Runtime output validation for the ACPI _DSD device configuration
object missing from the support for it that has been introduced
recently. From Mika Westerberg.
- Fix for an unuseful and misleading RAPL (Running Average Power
Limit) domain detection message in the RAPL driver from Jacob Pan.
- New Intel Haswell CPU ID for the RAPL driver from Jason Baron.
- New Clevo W350etq blacklist entry for the ACPI EC driver from Lan
Tianyu.
- Cleanup for the intel_pstate driver and the core generic PM domains
code from Gabriele Mazzotta and Geert Uytterhoeven"
* tag 'pm+acpi-3.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI / cpuidle: fix deadlock between cpuidle_lock and cpu_hotplug.lock
ACPI / scan: not cache _SUN value in struct acpi_device_pnp
cpufreq: intel_pstate: Remove unneeded variable
powercap / RAPL: change domain detection message
powercap / RAPL: add support for CPU model 0x3f
PM / domains: Make generic_pm_domain.name const
PM / sleep: Fix test_suspend= command line option
ACPI / EC: Add msi quirk for Clevo W350etq
ACPI / video: Disable native_backlight on HP ENVY 15 Notebook PC
ACPI / video: Add a disable_native_backlight quirk
ACPI / video: Fix use_native_backlight selection logic
ACPICA: ACPI 5.1: Add support for runtime validation of _DSD package.
Pull RCU fix from Ingo Molnar:
"A boot hang fix for the offloaded callback RCU model (RCU_NOCB_CPU=y
&& (TREE_CPU=y || TREE_PREEMPT_RC)) in certain bootup scenarios"
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
rcu: Make nocb leader kthreads process pending callbacks after spawning
Pull timer fixes from Thomas Gleixner:
"Three fixlets from the timer departement:
- Update the timekeeper before updating vsyscall and pvclock. This
fixes the kvm-clock regression reported by Chris and Paolo.
- Use the proper irq work interface from NMI. This fixes the
regression reported by Catalin and Dave.
- Clarify the compat_nanosleep error handling mechanism to avoid
future confusion"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Update timekeeper before updating vsyscall and pvclock
compat: nanosleep: Clarify error handling
nohz: Restore NMI safe local irq work for local nohz kick
An overrun could happen in function start_hrtick_dl()
when a task with SCHED_DEADLINE runs in the microseconds
range.
For example, if a task with SCHED_DEADLINE has the following parameters:
Task runtime deadline period
P1 200us 500us 500us
The deadline and period from task P1 are less than 1ms.
In order to achieve microsecond precision, we need to enable HRTICK feature
by the next command:
PC#echo "HRTICK" > /sys/kernel/debug/sched_features
PC#trace-cmd record -e sched_switch &
PC#./schedtool -E -t 200000:500000:500000 -e ./test
The binary test is in an endless while(1) loop here.
Some pieces of trace.dat are as follows:
<idle>-0 157.603157: sched_switch: :R ==> 2481:4294967295: test
test-2481 157.603203: sched_switch: 2481:R ==> 0:120: swapper/2
<idle>-0 157.605657: sched_switch: :R ==> 2481:4294967295: test
test-2481 157.608183: sched_switch: 2481:R ==> 2483:120: trace-cmd
trace-cmd-2483 157.609656: sched_switch:2483:R==>2481:4294967295: test
We can get the runtime of P1 from the information above:
runtime = 157.608183 - 157.605657
runtime = 0.002526(2.526ms)
The correct runtime should be less than or equal to 200us at some point.
The problem is caused by a conditional judgment "delta > 10000"
in function start_hrtick_dl().
Because no hrtimer start up to control the rest of runtime
when the reset of runtime is less than 10us.
So the process will continue to run until tick-period is coming.
Move the code with the limit of the least time slice
from hrtick_start_fair() to hrtick_start() because the
EDF schedule class also needs this function in start_hrtick_dl().
To fix this problem, we call hrtimer_start() unconditionally in
start_hrtick_dl(), and make sure the scheduling slice won't be smaller
than 10us in hrtimer_start().
Signed-off-by: Xiaofeng Yan <xiaofeng.yan@huawei.com>
Reviewed-by: Li Zefan <lizefan@huawei.com>
Acked-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409022941-5880-1-git-send-email-xiaofeng.yan@huawei.com
[ Massaged the changelog and the code. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The update_walltime() code works on the shadow timekeeper to make the
seqcount protected region as short as possible. But that update to the
shadow timekeeper does not update all timekeeper fields because it's
sufficient to do that once before it becomes life. One of these fields
is tkr.base_mono. That stays stale in the shadow timekeeper unless an
operation happens which copies the real timekeeper to the shadow.
The update function is called after the update calls to vsyscall and
pvclock. While not correct, it did not cause any problems because none
of the invoked update functions used base_mono.
commit cbcf2dd3b3 (x86: kvm: Make kvm_get_time_and_clockread()
nanoseconds based) changed that in the kvm pvclock update function, so
the stale mono_base value got used and caused kvm-clock to malfunction.
Put the update where it belongs and fix the issue.
Reported-by: Chris J Arges <chris.j.arges@canonical.com>
Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1409050000570.3333@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The error handling in compat_sys_nanosleep() is correct, but
completely non obvious. Document it and restrict it to the
-ERESTART_RESTARTBLOCK return value for clarity.
Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
With eBPF getting more extended and exposure to user space is on it's way,
hardening the memory range the interpreter uses to steer its command flow
seems appropriate. This patch moves the to be interpreted bytecode to
read-only pages.
In case we execute a corrupted BPF interpreter image for some reason e.g.
caused by an attacker which got past a verifier stage, it would not only
provide arbitrary read/write memory access but arbitrary function calls
as well. After setting up the BPF interpreter image, its contents do not
change until destruction time, thus we can setup the image on immutable
made pages in order to mitigate modifications to that code. The idea
is derived from commit 314beb9bca ("x86: bpf_jit_comp: secure bpf jit
against spraying attacks").
This is possible because bpf_prog is not part of sk_filter anymore.
After setup bpf_prog cannot be altered during its life-time. This prevents
any modifications to the entire bpf_prog structure (incl. function/JIT
image pointer).
Every eBPF program (including classic BPF that are migrated) have to call
bpf_prog_select_runtime() to select either interpreter or a JIT image
as a last setup step, and they all are being freed via bpf_prog_free(),
including non-JIT. Therefore, we can easily integrate this into the
eBPF life-time, plus since we directly allocate a bpf_prog, we have no
performance penalty.
Tested with seccomp and test_bpf testsuite in JIT/non-JIT mode and manual
inspection of kernel_page_tables. Brad Spengler proposed the same idea
via Twitter during development of this patch.
Joint work with Hannes Frederic Sowa.
Suggested-by: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The use of "rcu_assign_pointer()" is NULLing out the pointer.
According to RCU_INIT_POINTER()'s block comment:
"1. This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a
smaller overhead.
The following Coccinelle semantic patch was used:
@@
@@
- rcu_assign_pointer
+ RCU_INIT_POINTER
(..., NULL)
Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: paulmck@linux.vnet.ibm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140822145043.GA580@ada
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Provide device-managed implementations of the request_resource() and
release_resource() functions. Upon failure to request a resource, the new
devm_request_resource() function will output an error message for
consistent error reporting.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
The local nohz kick is currently used by perf which needs it to be
NMI-safe. Recent commit though (7d1311b93e)
changed its implementation to fire the local kick using the remote kick
API. It was convenient to make the code more generic but the remote kick
isn't NMI-safe.
As a result:
WARNING: CPU: 3 PID: 18062 at kernel/irq_work.c:72 irq_work_queue_on+0x11e/0x140()
CPU: 3 PID: 18062 Comm: trinity-subchil Not tainted 3.16.0+ #34
0000000000000009 00000000903774d1 ffff880244e06c00 ffffffff9a7f1e37
0000000000000000 ffff880244e06c38 ffffffff9a0791dd ffff880244fce180
0000000000000003 ffff880244e06d58 ffff880244e06ef8 0000000000000000
Call Trace:
<NMI> [<ffffffff9a7f1e37>] dump_stack+0x4e/0x7a
[<ffffffff9a0791dd>] warn_slowpath_common+0x7d/0xa0
[<ffffffff9a07930a>] warn_slowpath_null+0x1a/0x20
[<ffffffff9a17ca1e>] irq_work_queue_on+0x11e/0x140
[<ffffffff9a10a2c7>] tick_nohz_full_kick_cpu+0x57/0x90
[<ffffffff9a186cd5>] __perf_event_overflow+0x275/0x350
[<ffffffff9a184f80>] ? perf_event_task_disable+0xa0/0xa0
[<ffffffff9a01a4cf>] ? x86_perf_event_set_period+0xbf/0x150
[<ffffffff9a187934>] perf_event_overflow+0x14/0x20
[<ffffffff9a020386>] intel_pmu_handle_irq+0x206/0x410
[<ffffffff9a0b54d3>] ? arch_vtime_task_switch+0x63/0x130
[<ffffffff9a01937b>] perf_event_nmi_handler+0x2b/0x50
[<ffffffff9a007b72>] nmi_handle+0xd2/0x390
[<ffffffff9a007aa5>] ? nmi_handle+0x5/0x390
[<ffffffff9a0d131b>] ? lock_release+0xab/0x330
[<ffffffff9a008062>] default_do_nmi+0x72/0x1c0
[<ffffffff9a0c925f>] ? cpuacct_account_field+0xcf/0x200
[<ffffffff9a008268>] do_nmi+0xb8/0x100
Lets fix this by restoring the use of local irq work for the nohz local
kick.
Reported-by: Catalin Iacob <iacobcatalin@gmail.com>
Reported-and-tested-by: Dave Jones <davej@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Run these two scripts concurrently:
for ((; ;))
{
mkdir /cgroup/sub
rmdir /cgroup/sub
}
for ((; ;))
{
echo $$ > /cgroup/sub/cgroup.procs
echo $$ > /cgroup/cgroup.procs
}
A kernel bug will be triggered:
BUG: unable to handle kernel NULL pointer dereference at 00000038
IP: [<c10bbd69>] cgroup_put+0x9/0x80
...
Call Trace:
[<c10bbe19>] cgroup_kn_unlock+0x39/0x50
[<c10bbe91>] cgroup_kn_lock_live+0x61/0x70
[<c10be3c1>] __cgroup_procs_write.isra.26+0x51/0x230
[<c10be5b2>] cgroup_tasks_write+0x12/0x20
[<c10bb7b0>] cgroup_file_write+0x40/0x130
[<c11aee71>] kernfs_fop_write+0xd1/0x160
[<c1148e58>] vfs_write+0x98/0x1e0
[<c114934d>] SyS_write+0x4d/0xa0
[<c16f656b>] sysenter_do_call+0x12/0x12
We clear cgrp->kn->priv in the end of cgroup_rmdir(), but another
concurrent thread can access kn->priv after the clearing.
We should move the clearing to css_release_work_fn(). At that time
no one is holding reference to the cgroup and no one can gain a new
reference to access it.
v2:
- move RCU_INIT_POINTER() into the else block. (Tejun)
- remove the cgroup_parent() check. (Tejun)
- update the comment in css_tryget_online_from_dir().
Cc: <stable@vger.kernel.org> # 3.15+
Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Resolve some shadow warnings resulting from using the name
jiffies, which is a well-known global. This is not a problem
of course, but it could be a trap for someone copying and
pasting code, and it just makes W=2 a little cleaner.
Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1409739444-13635-1-git-send-email-jeffrey.t.kirsher@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
populate_seccomp_data is expensive: it works by inspecting
task_pt_regs and various other bits to piece together all the
information, and it's does so in multiple partially redundant steps.
Arch-specific code in the syscall entry path can do much better.
Admittedly this adds a bit of additional room for error, but the
speedup should be worth it.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
The reason I did this is to add a seccomp API that will be usable
for an x86 fast path. The x86 entry code needs to use a rather
expensive slow path for a syscall that might be visible to things
like ptrace. By splitting seccomp into two phases, we can check
whether we need the slow path and then use the fast path in if the
filter allows the syscall or just returns some errno.
As a side effect, I think the new code is much easier to understand
than the old code.
This has one user-visible effect: the audit record written for
SECCOMP_RET_TRACE is now a simple indication that SECCOMP_RET_TRACE
happened. It used to depend in a complicated way on what the tracer
did. I couldn't make much sense of it.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
The secure_computing function took a syscall number parameter, but
it only paid any attention to that parameter if seccomp mode 1 was
enabled. Rather than coming up with a kludge to get the parameter
to work in mode 2, just remove the parameter.
To avoid churn in arches that don't have seccomp filters (and may
not even support syscall_get_nr right now), this leaves the
parameter in secure_computing_strict, which is now a real function.
For ARM, this is a bit ugly due to the fact that ARM conditionally
supports seccomp filters. Fixing that would probably only be a
couple of lines of code, but it should be coordinated with the audit
maintainers.
This will be a slight slowdown on some arches. The right fix is to
pass in all of seccomp_data instead of trying to make just the
syscall nr part be fast.
This is a prerequisite for making two-phase seccomp work cleanly.
Cc: Russell King <linux@arm.linux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: x86@kernel.org
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
Calling irq_find_mapping from outside a irq_{enter,exit} section is
unsafe and produces ugly messages if CONFIG_PROVE_RCU is enabled:
If coming from the idle state, the rcu_read_lock call in irq_find_mapping
will generate an unpleasant warning:
<quote>
===============================
[ INFO: suspicious RCU usage. ]
3.16.0-rc1+ #135 Not tainted
-------------------------------
include/linux/rcupdate.h:871 rcu_read_lock() used illegally while idle!
other info that might help us debug this:
RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 0
RCU used illegally from extended quiescent state!
1 lock held by swapper/0/0:
#0: (rcu_read_lock){......}, at: [<ffffffc00010206c>]
irq_find_mapping+0x4c/0x198
</quote>
As this issue is fairly widespread and involves at least three
different architectures, a possible solution is to add a new
handle_domain_irq entry point into the generic IRQ code that
the interrupt controller code can call.
This new function takes an irq_domain, and calls into irq_find_domain
inside the irq_{enter,exit} block. An additional "lookup" parameter is
used to allow non-domain architecture code to be replaced by this as well.
Interrupt controllers can then be updated to use the new mechanism.
This code is sitting behind a new CONFIG_HANDLE_DOMAIN_IRQ, as not all
architectures implement set_irq_regs (yes, mn10300, I'm looking at you...).
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/1409047421-27649-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Pull an RCU fix from Paul E. McKenney:
"This series contains a single commit fixing an initialization bug
reported by Amit Shah and fixed by Pranith Kumar (and tested by Amit).
This bug results in a boot-time hang in callback-offloaded configurations
where callbacks were posted before the offloading ('rcuo') kthreads
were created."
Signed-off-by: Ingo Molnar <mingo@kernel.org>
After commit d431cbc53c (PM / sleep: Simplify sleep states sysfs
interface code) the pm_states[] array is not populated initially,
which causes setup_test_suspend() to always fail and the suspend
testing during boot doesn't work any more.
Fix the problem by using pm_labels[] instead of pm_states[] in
setup_test_suspend() and storing a pointer to the label of the
sleep state to test rather than the number representing it,
because the connection between the state numbers and labels is
only established by suspend_set_ops().
Fixes: d431cbc53c (PM / sleep: Simplify sleep states sysfs interface code)
Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull irq handling fixlet from Thomas Gleixner:
"Just an export for an interrupt flow handler which is now used in gpio
modules"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irq: Export handle_fasteoi_irq
Currently we suspend wakeup interrupts by lazy disabling them and
check later whether the interrupt has fired, but that's not sufficient
for suspend to idle as there is no way to check that once we
transitioned into the CPU idle state.
So we change the mechanism in the following way:
1) Leave the wakeup interrupts enabled across suspend
2) Add a check to irq_may_run() which is called at the beginning of
each flow handler whether the interrupt is an armed wakeup source.
This check is basically free as it just extends the existing check
for IRQD_IRQ_INPROGRESS. So no new conditional in the hot path.
If the IRQD_WAKEUP_ARMED flag is set, then the interrupt is
disabled, marked as pending/suspended and the pm core is notified
about the wakeup event.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ rjw: syscore.c and put irq_pm_check_wakeup() into pm.c ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This allows us to utilize this information in the irq_may_run() check
without adding another conditional to the fast path.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
All flow handlers - except the per cpu ones - check for an interrupt
in progress and an eventual concurrent polling on another cpu.
Create a helper function for the repeated code pattern.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If the interrupt is disabled or has no action, then we should not call
the poll check. Separate the checks.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
We can synchronize the suspended interrupts right away. No need for an
extra loop.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There is no reason why we should delay the masking of interrupts whose
interrupt chip requests MASK_ON_SUSPEND to the point where we check
the wakeup interrupts. We can do it right at the point where we mark
the interrupt as suspended.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Use the accounting fields which got introduced for snity checking for
the various PM options.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Account the IRQF_NO_SUSPEND and IRQF_RESUME_EARLY actions on shared
interrupt lines and yell loudly if there is a mismatch.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
No functional change. Preparatory patch for cleaning up the suspend
abort functionality. Update the comments while at it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
It sometimes may be necessary to abort a system suspend in
progress or wake up the system from suspend-to-idle even if the
pm_wakeup_event()/pm_stay_awake() mechanism is not enabled.
For this purpose, introduce a new global variable pm_abort_suspend
and make pm_wakeup_pending() check its value. Also add routines
for manipulating that variable.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently new system call kexec_file_load() and all the associated code
compiles if CONFIG_KEXEC=y. But new syscall also compiles purgatory
code which currently uses gcc option -mcmodel=large. This option seems
to be available only gcc 4.4 onwards.
Hiding new functionality behind a new config option will not break
existing users of old gcc. Those who wish to enable new functionality
will require new gcc. Having said that, I am trying to figure out how
can I move away from using -mcmodel=large but that can take a while.
I think there are other advantages of introducing this new config
option. As this option will be enabled only on x86_64, other arches
don't have to compile generic kexec code which will never be used. This
new code selects CRYPTO=y and CRYPTO_SHA256=y. And all other arches had
to do this for CONFIG_KEXEC. Now with introduction of new config
option, we can remove crypto dependency from other arches.
Now CONFIG_KEXEC_FILE is available only on x86_64. So whereever I had
CONFIG_X86_64 defined, I got rid of that.
For CONFIG_KEXEC_FILE, instead of doing select CRYPTO=y, I changed it to
"depends on CRYPTO=y". This should be safer as "select" is not
recursive.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Tested-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Richard and Daniel reported that UML is broken due to changes to
resource traversal functions. Problem is that iomem_resource.child can
be null and new code does not consider that possibility. Old code used
a for loop and that loop will not even execute if p was null.
Revert back to for() loop logic and bail out if p is null.
I also moved sibling_only check out of resource_lock. There is no
reason to keep it inside the lock.
Following is backtrace of the UML crash.
RIP: 0033:[<0000000060039b9f>]
RSP: 0000000081459da0 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 00000000219b3fff RCX: 000000006010d1d9
RDX: 0000000000000001 RSI: 00000000602dfb94 RDI: 0000000081459df8
RBP: 0000000081459de0 R08: 00000000601b59f4 R09: ffffffff0000ff00
R10: ffffffff0000ff00 R11: 0000000081459e88 R12: 0000000081459df8
R13: 00000000219b3fff R14: 00000000602dfb94 R15: 0000000000000000
Kernel panic - not syncing: Segfault with no mm
CPU: 0 PID: 1 Comm: swapper Not tainted 3.16.0-10454-g58d08e3 #13
Stack:
00000000 000080d0 81459df0 219b3fff
81459e70 6010d1d9 ffffffff 6033e010
81459e50 6003a269 81459e30 00000000
Call Trace:
[<6010d1d9>] ? kclist_add_private+0x0/0xe7
[<6003a269>] walk_system_ram_range+0x61/0xb7
[<6000e859>] ? proc_kcore_init+0x0/0xf1
[<6010d574>] kcore_update_ram+0x4c/0x168
[<6010d72e>] ? kclist_add+0x0/0x2e
[<6000e943>] proc_kcore_init+0xea/0xf1
[<6000e859>] ? proc_kcore_init+0x0/0xf1
[<6000e859>] ? proc_kcore_init+0x0/0xf1
[<600189f0>] do_one_initcall+0x13c/0x204
[<6004ca46>] ? parse_args+0x1df/0x2e0
[<6004c82d>] ? parameq+0x0/0x3a
[<601b5990>] ? strcpy+0x0/0x18
[<60001e1a>] kernel_init_freeable+0x240/0x31e
[<6026f1c0>] kernel_init+0x12/0x148
[<60019fad>] new_thread_handler+0x81/0xa3
Fixes 8c86e70ace ("resource: provide new functions to walk
through resources").
Reported-by: Daniel Walter <sahne@0x90.at>
Tested-by: Richard Weinberger <richard@nod.at>
Tested-by: Toralf Förster <toralf.foerster@gmx.de>
Tested-by: Daniel Walter <sahne@0x90.at>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It should be request_threaded_irq, not request_irq
[jkosina@suse.cz: not that it would matter, as both have the same
set of arguments anyway, but for sake of consistency ...]
Signed-off-by: Emilio López <emilio@elopez.com.ar>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
The nocb callbacks generated before the nocb kthreads are spawned are
enqueued in the nocb queue for later processing. Commit fbce7497ee ("rcu:
Parallelize and economize NOCB kthread wakeups") introduced nocb leader kthreads
which checked the nocb_leader_wake flag to see if there were any such pending
callbacks. A case was reported in which newly spawned leader kthreads were not
processing the pending callbacks as this flag was not set, which led to a boot
hang.
The following commit ensures that the newly spawned nocb kthreads process the
pending callbacks by allowing the kthreads to run immediately after spawning
instead of waiting. This is done by inverting the logic of nocb_leader_wake
tests to nocb_leader_sleep which allows us to use the default initialization of
this flag to 0 to let the kthreads run.
Reported-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Link: http://www.spinics.net/lists/kernel/msg1802899.html
[ paulmck: Backported to v3.17-rc2. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Amit Shah <amit.shah@redhat.com>
__get_cpu_var can paper over differences in the definitions of
cpumask_var_t and either use the address of the cpumask variable
directly or perform a fetch of the address of the struct cpumask
allocated elsewhere. This is important particularly when using per cpu
cpumask_var_t declarations because in one case we have an offset into
a per cpu area to handle and in the other case we need to fetch a
pointer from the offset.
This patch introduces a new macro
this_cpu_cpumask_var_ptr()
that is defined where cpumask_var_t is defined and performs the proper
actions. All use cases where __get_cpu_var is used with cpumask_var_t
are converted to the use of this_cpu_cpumask_var_ptr().
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
condition variable (waiters_pending) was set before being added to
the poll queue via poll_wait(). This allowed for a small race window
to happen where an event could come in, check the condition variable
see it set to true, clear it, and then wake all the waiters. But because
the waiter set the variable before adding itself to the queue, the
waker could have cleared the variable after it was set and then miss
waking it up as it wasn't added to the queue yet.
Discussing this bug, we realized that a memory barrier needed to be added
too, for the rare case that something polls for a single trace event
to happen (and just one, no more to come in), and miss the wakeup due
to memory ordering. Ideally, a memory barrier needs to be added on the
writer side too, but as that will kill tracing performance and this is
for a situation that tracing wasn't even designed for (who traces one
instance of an event, use a printk instead!), this isn't worth adding the
barrier. But we can in the future add the barrier for when the buffer
goes from empty to the first event, as that would cover this case.
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Merge tag 'trace-fixes-v3.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull trace buffer epoll hang fix from Steven Rostedt:
"Josef Bacik found a bug in the ring_buffer_poll_wait() where the
condition variable (waiters_pending) was set before being added to the
poll queue via poll_wait(). This allowed for a small race window to
happen where an event could come in, check the condition variable see
it set to true, clear it, and then wake all the waiters. But because
the waiter set the variable before adding itself to the queue, the
waker could have cleared the variable after it was set and then miss
waking it up as it wasn't added to the queue yet.
Discussing this bug, we realized that a memory barrier needed to be
added too, for the rare case that something polls for a single trace
event to happen (and just one, no more to come in), and miss the
wakeup due to memory ordering. Ideally, a memory barrier needs to be
added on the writer side too, but as that will kill tracing
performance and this is for a situation that tracing wasn't even
designed for (who traces one instance of an event, use a printk
instead!), this isn't worth adding the barrier. But we can in the
future add the barrier for when the buffer goes from empty to the
first event, as that would cover this case"
* tag 'trace-fixes-v3.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
trace: Fix epoll hang when we race with new entries
Add flags field to struct kernel_params, and add the first flag: unsafe
parameter. Modifying a kernel parameter with the unsafe flag set, either
via the kernel command line or sysfs, will issue a warning and taint the
kernel.
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Jon Mason <jon.mason@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Make it clear this is about kernel_param_ops, not kernel_param (which
will soon have a flags field of its own). No functional changes.
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Jon Mason <jon.mason@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Pull nohz fixes from Frederic Weisbecker:
" The tick reschedules itself unconditionally. It's relevant in periodic
mode but not in dynticks mode where it results in spurious double clock
writes and even spurious periodic behaviour for low-res case.
This set fixes that:
* 1st patch removes low-res periodic tick rescheduling in nohz mode.
This fixes spurious periodic behaviour.
* 2nd patch does the same for high-res mode. Here there is no such
spurious periodic behaviour but it still spares a double clock write
in some cases. "
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[ARM specific]
These are generally replaced with raw_cpu_ptr. However, in
gic_get_percpu_base() we immediately dereference the pointer. This is
equivalent to a raw_cpu_read. So use that operation there.
Cc: nicolas.pitre@linaro.org
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Most of these are the uses of &__raw_get_cpu_var for address calculation.
touch_softlockup_watchdog_sync() uses __raw_get_cpu_var to write to
per cpu variables. Use __this_cpu_write instead.
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: linux-watchdog@vger.kernel.org
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Convert all uses of __get_cpu_var for address calculation to use
this_cpu_ptr instead.
[Uses of __get_cpu_var with cpumask_var_t are no longer
handled by this patch]
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Convert uses of __get_cpu_var for creating a address from a percpu
offset to this_cpu_ptr.
The two cases where get_cpu_var is used to actually access a percpu
variable are changed to use this_cpu_read/raw_cpu_read.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Replace uses of __get_cpu_var for address calculation with this_cpu_ptr.
Cc: akpm@linux-foundation.org
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Epoll on trace_pipe can sometimes hang in a weird case. If the ring buffer is
empty when we set waiters_pending but an event shows up exactly at that moment
we can miss being woken up by the ring buffers irq work. Since
ring_buffer_empty() is inherently racey we will sometimes think that the buffer
is not empty. So we don't get woken up and we don't think there are any events
even though there were some ready when we added the watch, which makes us hang.
This patch fixes this by making sure that we are actually on the wait list
before we set waiters_pending, and add a memory barrier to make sure
ring_buffer_empty() is going to be correct.
Link: http://lkml.kernel.org/p/1408989581-23727-1-git-send-email-jbacik@fb.com
Cc: stable@vger.kernel.org # 3.10+
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In order to make is_kdump_kernel() accessible from modules, need to
make elfcorehdr_addr exported.
This was rejected in the past [1] because reset_devices was prefered in
that context (reseting the device in kdump kernel), but now there are
some network drivers that need to reduce memory usage when loaded from
a kdump kernel. And in that context, is_kdump_kernel() suits better.
[1] - https://lkml.org/lkml/2011/1/27/341
CC: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
separate trampolines had a design flaw with the interaction between
the function and function_graph tracers.
The main flaw was the simplification of the use of multiple tracers having
the same filter (like function and function_graph, that use the
set_ftrace_filter file to filter their code). The design assumed that the
two tracers could never run simultaneously as only one tracer can be
used at a time. The problem with this assumption was that the function
profiler could be implemented on top of the function graph tracer, and
the function profiler could run at the same time as the function tracer.
This caused the assumption to be broken and when ftrace detected this
failed assumpiton it would spit out a nasty warning and shut itself down.
Instead of using a single ftrace_ops that switches between the function
and function_graph callbacks, the two tracers can again use their own
ftrace_ops. But instead of having a complex hierarchy of ftrace_ops,
the filter fields are placed in its own structure and the ftrace_ops
can carefully use the same filter. This change took a bit to be able
to allow for this and currently only the global_ops can share the same
filter, but this new design can easily be modified to allow for any
ftrace_ops to share its filter with another ftrace_ops.
The first four patches deal with the change of allowing the ftrace_ops
to share the filter (and this needs to go to 3.16 as well).
The fifth patch fixes a bug that was also caused by the new changes
but only for archs other than x86, and only if those archs implement
a direct call to the function_graph tracer which they do not do yet
but will in the future. It does not need to go to stable, but needs
to be fixed before the other archs update their code to allow direct
calls to the function_graph trampoline.
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Merge tag 'trace-fixes-v3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull fix for ftrace function tracer/profiler conflict from Steven Rostedt:
"The rewrite of the ftrace code that makes it possible to allow for
separate trampolines had a design flaw with the interaction between
the function and function_graph tracers.
The main flaw was the simplification of the use of multiple tracers
having the same filter (like function and function_graph, that use the
set_ftrace_filter file to filter their code). The design assumed that
the two tracers could never run simultaneously as only one tracer can
be used at a time. The problem with this assumption was that the
function profiler could be implemented on top of the function graph
tracer, and the function profiler could run at the same time as the
function tracer. This caused the assumption to be broken and when
ftrace detected this failed assumpiton it would spit out a nasty
warning and shut itself down.
Instead of using a single ftrace_ops that switches between the
function and function_graph callbacks, the two tracers can again use
their own ftrace_ops. But instead of having a complex hierarchy of
ftrace_ops, the filter fields are placed in its own structure and the
ftrace_ops can carefully use the same filter. This change took a bit
to be able to allow for this and currently only the global_ops can
share the same filter, but this new design can easily be modified to
allow for any ftrace_ops to share its filter with another ftrace_ops.
The first four patches deal with the change of allowing the ftrace_ops
to share the filter (and this needs to go to 3.16 as well).
The fifth patch fixes a bug that was also caused by the new changes
but only for archs other than x86, and only if those archs implement a
direct call to the function_graph tracer which they do not do yet but
will in the future. It does not need to go to stable, but needs to be
fixed before the other archs update their code to allow direct calls
to the function_graph trampoline"
* tag 'trace-fixes-v3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Use current addr when converting to nop in __ftrace_replace_code()
ftrace: Fix function_profiler and function tracer together
ftrace: Fix up trampoline accounting with looping on hash ops
ftrace: Update all ftrace_ops for a ftrace_hash_ops update
ftrace: Allow ftrace_ops to use the hashes from other ops
Export handle_fasteoi_irq to be able to use it in e.g. the Zynq gpio driver
since commit 6dd8595083 ("gpio: zynq: Fix IRQ handlers").
This fixes the following link issue:
ERROR: "handle_fasteoi_irq" [drivers/gpio/gpio-zynq.ko] undefined!
Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Vincent Stehle <vincent.stehle@laposte.net>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Link: http://lkml.kernel.org/r/1408663880-29179-1-git-send-email-vincent.stehle@laposte.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
There is no function named cgroup_enable_task_cg_links().
Instead, the correct function name in this comment should
be cgroup_enabled_task_cg_lists().
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This function will help an async task processing batched jobs from
workqueue decide if it wants to keep processing on more chunks of batched
work that can be delayed, or to accumulate more work for more efficient
batched processing later.
If no other tasks are running on the cpu, the batching process can take
advantgae of the available cpu cycles to a make decision to continue
processing the existing accumulated work to minimize delay,
otherwise it will yield.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull perf fixes from Ingo Molnar:
"A kprobes and a perf compat ioctl fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Handle compat ioctl
kprobes: Skip kretprobe hit in NMI context to avoid deadlock
Adding new perf event state to indicate that the monitored task has
exited. In this case the event stays alive until the owner task exits
or close the event fd while providing the last data through the read
syscall and ring buffer.
Instead it needs to propagate the error info (monitored task has died)
via poll and read syscalls by returning POLLHUP and 0 respectively.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140811120102.GY9918@twins.programming.kicks-ass.net
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-t5y3w8jjx6tfo5w8y6oajsjq@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently perf_poll returns POLL_HUP in case of error, which is wrong,
because poll syscall expects POLLHUP. The POLL_HUP is meant to be used
for SIGIO state.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140811120102.GY9918@twins.programming.kicks-ass.net
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-0ywfthh4lh65swe15f6w2x2q@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In __ftrace_replace_code(), when converting the call to a nop in a function
it needs to compare against the "curr" (current) value of the ftrace ops, and
not the "new" one. It currently does not affect x86 which is the only arch
to do the trampolines with function graph tracer, but when other archs that do
depend on this code implement the function graph trampoline, it can crash.
Here's an example when ARM uses the trampolines (in the future):
------------[ cut here ]------------
WARNING: CPU: 0 PID: 9 at kernel/trace/ftrace.c:1716 ftrace_bug+0x17c/0x1f4()
Modules linked in: omap_rng rng_core ipv6
CPU: 0 PID: 9 Comm: migration/0 Not tainted 3.16.0-test-10959-gf0094b28f303-dirty #52
[<c02188f4>] (unwind_backtrace) from [<c021343c>] (show_stack+0x20/0x24)
[<c021343c>] (show_stack) from [<c095a674>] (dump_stack+0x78/0x94)
[<c095a674>] (dump_stack) from [<c02532a0>] (warn_slowpath_common+0x7c/0x9c)
[<c02532a0>] (warn_slowpath_common) from [<c02532ec>] (warn_slowpath_null+0x2c/0x34)
[<c02532ec>] (warn_slowpath_null) from [<c02cbac4>] (ftrace_bug+0x17c/0x1f4)
[<c02cbac4>] (ftrace_bug) from [<c02cc44c>] (ftrace_replace_code+0x80/0x9c)
[<c02cc44c>] (ftrace_replace_code) from [<c02cc658>] (ftrace_modify_all_code+0xb8/0x164)
[<c02cc658>] (ftrace_modify_all_code) from [<c02cc718>] (__ftrace_modify_code+0x14/0x1c)
[<c02cc718>] (__ftrace_modify_code) from [<c02c7244>] (multi_cpu_stop+0xf4/0x134)
[<c02c7244>] (multi_cpu_stop) from [<c02c6e90>] (cpu_stopper_thread+0x54/0x130)
[<c02c6e90>] (cpu_stopper_thread) from [<c0271cd4>] (smpboot_thread_fn+0x1ac/0x1bc)
[<c0271cd4>] (smpboot_thread_fn) from [<c026ddf0>] (kthread+0xe0/0xfc)
[<c026ddf0>] (kthread) from [<c020f318>] (ret_from_fork+0x14/0x20)
---[ end trace dc9ce72c5b617d8f ]---
[ 65.047264] ftrace failed to modify [<c0208580>] asm_do_IRQ+0x10/0x1c
[ 65.054070] actual: 85:1b:00:eb
Fixes: 7413af1fb7 "ftrace: Make get_ftrace_addr() and get_ftrace_addr_old() global"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The latest rewrite of ftrace removed the separate ftrace_ops of
the function tracer and the function graph tracer and had them
share the same ftrace_ops. This simplified the accounting by removing
the multiple layers of functions called, where the global_ops func
would call a special list that would iterate over the other ops that
were registered within it (like function and function graph), which
itself was registered to the ftrace ops list of all functions
currently active. If that sounds confusing, the code that implemented
it was also confusing and its removal is a good thing.
The problem with this change was that it assumed that the function
and function graph tracer can never be used at the same time.
This is mostly true, but there is an exception. That is when the
function profiler uses the function graph tracer to profile.
The function profiler can be activated the same time as the function
tracer, and this breaks the assumption and the result is that ftrace
will crash (it detects the error and shuts itself down, it does not
cause a kernel oops).
To solve this issue, a previous change allowed the hash tables
for the functions traced by a ftrace_ops to be a pointer and let
multiple ftrace_ops share the same hash. This allows the function
and function_graph tracer to have separate ftrace_ops, but still
share the hash, which is what is done.
Now the function and function graph tracers have separate ftrace_ops
again, and the function tracer can be run while the function_profile
is active.
Cc: stable@vger.kernel.org # 3.16 (apply after 3.17-rc4 is out)
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Now that a ftrace_hash can be shared by multiple ftrace_ops, they can dec
the rec->flags by more than once (one per those that share the ftrace_hash).
This means that the tramp_hash may not have a hash item when it was added.
For example, if two ftrace_ops share a hash for a ftrace record, and the
first ops has a trampoline, when it adds itself it will set the rec->flags
TRAMP flag and increments its nr_trampolines counter. When the second ops
is added, it must clear that tramp flag but also decrement the other ops
that shares its hash. As the update to the function callbacks has not yet
been performed, the other ops will not have the tramp hash set yet and it
can not be used to know to decrement its nr_trampolines.
Luckily, the tramp_hash does not need to be used. As the ftrace_mutex is
held, a ops with a trampoline to a record during an update of another ops
that shares the record will have its func_hash pointing to it. Since a
trampoline can only be set for a record if only one ops is attached to it,
we can just check if the record has a trampoline (the FTRACE_FL_TRAMP flag
is set) and then find the ops that has this record in its hashes.
Also added some output to help debug when things go wrong.
Cc: stable@vger.kernel.org # 3.16+ (apply after 3.17-rc4 is out)
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When updating what an ftrace_ops traces, if it is registered (that is,
actively tracing), and that ftrace_ops uses the shared global_ops
local_hash, then we need to update all tracers that are active and
also share the global_ops' ftrace_hash_ops.
Cc: stable@vger.kernel.org # 3.16 (apply after 3.17-rc4 is out)
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Kernel command line parameter cgroup__DEVEL__legacy_files_on_dfl forces
legacy cgroup files to show up on default hierarhcy if susbsystem does
not have any files defined for default hierarchy.
But this seems to be working only if legacy files are defined in
ss->legacy_cftypes. If one adds some cftypes later using
cgroup_add_legacy_cftypes(), these files don't show up on default
hierarchy. Update the function accordingly so that the dynamically
added legacy files also show up in the default hierarchy if the target
subsystem is also using the base legacy files for the default
hierarchy.
tj: Patch description and comment updates.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Currently the top level debug file system function tracer shares its
ftrace_ops with the function graph tracer. This was thought to be fine
because the tracers are not used together, as one can only enable
function or function_graph tracer in the current_tracer file.
But that assumption proved to be incorrect. The function profiler
can use the function graph tracer when function tracing is enabled.
Since all function graph users uses the function tracing ftrace_ops
this causes a conflict and when a user enables both function profiling
as well as the function tracer it will crash ftrace and disable it.
The quick solution so far is to move them as separate ftrace_ops like
it was earlier. The problem though is to synchronize the functions that
are traced because both function and function_graph tracer are limited
by the selections made in the set_ftrace_filter and set_ftrace_notrace
files.
To handle this, a new structure is made called ftrace_ops_hash. This
structure will now hold the filter_hash and notrace_hash, and the
ftrace_ops will point to this structure. That will allow two ftrace_ops
to share the same hashes.
Since most ftrace_ops do not share the hashes, and to keep allocation
simple, the ftrace_ops structure will include both a pointer to the
ftrace_ops_hash called func_hash, as well as the structure itself,
called local_hash. When the ops are registered, the func_hash pointer
will be initialized to point to the local_hash within the ftrace_ops
structure. Some of the ftrace internal ftrace_ops will be initialized
statically. This will allow for the function and function_graph tracer
to have separate ops but still share the same hash tables that determine
what functions they trace.
Cc: stable@vger.kernel.org # 3.16 (apply after 3.17-rc4 is out)
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In highres mode, the tick reschedules itself unconditionally to the
next jiffies.
However while this clock reprogramming is relevant when the tick is
in periodic mode, it's not that interesting when we run in dynticks mode
because irq exit is likely going to overwrite the next tick to some
randomly deferred future.
So lets just get rid of this tick self rescheduling in dynticks mode.
This way we can avoid some clockevents double write in favourable
scenarios like when we stop the tick completely in idle while no other
hrtimer is pending.
Suggested-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
When we reach the end of the tick handler, we unconditionally reschedule
the next tick to the next jiffy. Then on irq exit, the nohz code
overrides that setting if needed and defers the next tick as far away in
the future as possible.
Now in the best dynticks case, when we actually don't need any tick in
the future (ie: expires == KTIME_MAX), low-res and high-res behave
differently. What we want in this case is to cancel the next tick
programmed by the previous one. That's what we do in high-res mode. OTOH
we lack a low-res mode equivalent of hrtimer_cancel() so we simply don't
do anything in this case and the next tick remains scheduled to jiffies + 1.
As a result, in low-res mode, when the dynticks code determines that no
tick is needed in the future, we can recursively get a spurious tick
every jiffy because then the next tick is always reprogrammed from the
tick handler and is never cancelled. And this can happen indefinetly
until some subsystem actually needs a precise tick in the future and only
then we eventually overwrite the previous tick handler setting to defer
the next tick.
We are fixing this by introducing the ONESHOT_STOPPED mode which will
let us pause a clockevent when no further interrupt is needed. Meanwhile
we can't expect all drivers to support this new mode.
So lets reduce much of the symptoms by skipping the nohz-blind tick
rescheduling from the tick-handler when the CPU is in dynticks mode.
That tick rescheduling wrongly assumed periodicity and the low-res
dynticks code can't cancel such decision. This breaks the recursive (and
thus the worst) part of the problem. In the worst case now, we'll get
only one extra tick due to uncancelled tick scheduled before we entered
dynticks mode.
This also removes a needless clockevent write on idle ticks. Since those
clock write are usually considered to be slow, it's a general win.
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Avoid double_rq_lock() and use TASK_ON_RQ_MIGRATING for
load_balance(). The advantage is (obviously) not holding two
rq->lock's at the same time and thereby increasing parallelism.
Further note that if there was no task to migrate we will not
have acquired the second rq->lock at all.
The important point to note is that because we acquire dst->lock
immediately after releasing src->lock the potential wait time of
task_rq_lock() callers on TASK_ON_RQ_MIGRATING is not longer
than it would have been in the double rq lock scenario.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1408528109.23412.94.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Avoid double_rq_lock() and use the TASK_ON_RQ_MIGRATING state for
active_load_balance_cpu_stop(). The advantage is (obviously) not
holding two 'rq->lock's at the same time and thereby increasing
parallelism.
Further note that if there was no task to migrate we will not
have acquired the second rq->lock at all.
The important point to note is that because we acquire dst->lock
immediately after releasing src->lock the potential wait time of
task_rq_lock() callers on TASK_ON_RQ_MIGRATING is not longer
than it would have been in the double rq lock scenario.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1408528081.23412.92.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Avoid double_rq_lock() and use TASK_ON_RQ_MIGRATING for
__migrate_task(). The advantage is (obviously) not holding two
rq->lock's at the same time and thereby increasing parallelism.
The important point to note is that because we acquire dst->lock
immediately after releasing src->lock the potential wait time of
task_rq_lock() callers on TASK_ON_RQ_MIGRATING is not longer
than it would have been in the double rq lock scenario.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1408528070.23412.89.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This is a new p->on_rq state which will be used to indicate that a task
is in a process of migrating between two RQs. It allows to get
rid of double_rq_lock(), which we used to use to change a rq of
a queued task before.
Let's consider an example. To move a task between src_rq and
dst_rq we will do the following:
raw_spin_lock(&src_rq->lock);
/* p is a task which is queued on src_rq */
p = ...;
dequeue_task(src_rq, p, 0);
p->on_rq = TASK_ON_RQ_MIGRATING;
set_task_cpu(p, dst_cpu);
raw_spin_unlock(&src_rq->lock);
/*
* Both RQs are unlocked here.
* Task p is dequeued from src_rq
* but its on_rq value is not zero.
*/
raw_spin_lock(&dst_rq->lock);
p->on_rq = TASK_ON_RQ_QUEUED;
enqueue_task(dst_rq, p, 0);
raw_spin_unlock(&dst_rq->lock);
While p->on_rq is TASK_ON_RQ_MIGRATING, task is considered as
"migrating", and other parallel scheduler actions with it are
not available to parallel callers. The parallel caller is
spining till migration is completed.
The unavailable actions are changing of cpu affinity, changing
of priority etc, in other words all the functionality which used
to require task_rq(p)->lock before (and related to the task).
To implement TASK_ON_RQ_MIGRATING support we primarily are using
the following fact. Most of scheduler users (from which we are
protecting a migrating task) use task_rq_lock() and
__task_rq_lock() to get the lock of task_rq(p). These primitives
know that task's cpu may change, and they are spining while the
lock of the right RQ is not held. We add one more condition into
them, so they will be also spinning until the migration is
finished.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1408528062.23412.88.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Implement task_on_rq_queued() and use it everywhere instead of
on_rq check. No functional changes.
The only exception is we do not use the wrapper in
check_for_tasks(), because it requires to export
task_on_rq_queued() in global header files. Next patch in series
would return it back, so we do not twist it from here to there.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1408528052.23412.87.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(sched_entity::on_rq == 1) does not guarantee the task is pickable;
changes on throttled cfs_rq must not lead to reschedule.
Check for task_struct::on_rq instead.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1407312361.8424.35.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Match the declaration of runqueues with the definition.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1407950893-32731-1-git-send-email-bobby.prani@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When running a 32-bit userspace on a 64-bit kernel (eg. i386
application on x86_64 kernel or 32-bit arm userspace on arm64
kernel) some of the perf ioctls must be treated with special
care, as they have a pointer size encoded in the command.
For example, PERF_EVENT_IOC_ID in 32-bit world will be encoded
as 0x80042407, but 64-bit kernel will expect 0x80082407. In
result the ioctl will fail returning -ENOTTY.
This patch solves the problem by adding code fixing up the
size as compat_ioctl file operation.
Reported-by: Drew Richardson <drew.richardson@arm.com>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1402671812-9078-1-git-send-email-pawel.moll@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
/proc/<pid>/cgroup contains one cgroup path on each line. If cgroup names are
allowed to contain "\n", applications cannot parse /proc/<pid>/cgroup safely.
Signed-off-by: Alban Crequy <alban.crequy@collabora.co.uk>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
This patch avoids printing the message 'enabled on all CPUs,
...' multiple times. For example, the issue can occur in the
following scenario:
1) watchdog_nmi_enable() fails to enable PMU counters and sets
cpu0_err.
2) 'echo [0|1] > /proc/sys/kernel/nmi_watchdog' is executed to
disable and re-enable the watchdog mechanism 'on the fly'.
3) If watchdog_nmi_enable() succeeds to enable PMU counters,
each CPU will print the message because step1 left behind a
non-zero cpu0_err.
if (!IS_ERR(event)) {
if (cpu == 0 || cpu0_err)
pr_info("enabled on all CPUs, ...")
The patch avoids this by clearing cpu0_err in watchdog_nmi_disable().
Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: pbonzini@redhat.com
Link: http://lkml.kernel.org/r/1407768567-171794-4-git-send-email-dzickus@redhat.com
[ Applied small cleanups. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Many embedded systems will not need these syscalls, and omitting them
saves space. Add a new EXPERT config option CONFIG_ADVISE_SYSCALLS
(default y) to support compiling them out.
bloat-o-meter:
add/remove: 0/3 grow/shrink: 0/0 up/down: 0/-2250 (-2250)
function old new delta
sys_fadvise64 57 - -57
sys_fadvise64_64 691 - -691
sys_madvise 1502 - -1502
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
The commit
4982223e51 module: set nx before marking module MODULE_STATE_COMING.
introduced a regression: if a module fails to parse its arguments or
if mod_sysfs_setup fails, then the module's memory will be freed
while still read-only. Anything that reuses that memory will crash
as soon as it tries to write to it.
Cc: stable@vger.kernel.org # v3.16
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
- Fix for an ACPI-based device hotplug regression introduced in 3.14
that causes a kernel panic to trigger when memory hot-remove is
attempted with CONFIG_ACPI_HOTPLUG_MEMORY unset from Tang Chen.
- Fix for a cpufreq regression introduced in 3.16 that triggers a
"sleeping function called from invalid context" bug in
dev_pm_opp_init_cpufreq_table() from Stephen Boyd.
- ACPI battery driver fix for a warning message added in 3.16 that
prints silly stuff sometimes from Mariusz Ceier.
- Hibernation fix for safer handling of mismatches in the 820 memory
map between the configurations during image creation and during
the subsequent restore from Chun-Yi Lee.
- ACPI processor driver fix to handle CPU hotplug notifications
correctly during system suspend/resume from Lan Tianyu.
- Series of four cpuidle menu governor cleanups that also should
speed it up a bit from Mel Gorman.
- Fixes for the speedstep-smi, integrator, cpu0 and arm_big_little
cpufreq drivers from Hans Wennborg, Himangi Saraogi, Markus Pargmann
and Uwe Kleine-König.
- Version 3.0 of the analyze_suspend.py suspend profiling tool
from Todd E Brandt.
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Merge tag 'pm+acpi-3.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull more ACPI and power management updates from Rafael Wysocki:
"These are a couple of regression fixes, cpuidle menu governor
optimizations, fixes for ACPI proccessor and battery drivers,
hibernation fix to avoid problems related to the e820 memory map,
fixes for a few cpufreq drivers and a new version of the suspend
profiling tool analyze_suspend.py.
Specifics:
- Fix for an ACPI-based device hotplug regression introduced in 3.14
that causes a kernel panic to trigger when memory hot-remove is
attempted with CONFIG_ACPI_HOTPLUG_MEMORY unset from Tang Chen
- Fix for a cpufreq regression introduced in 3.16 that triggers a
"sleeping function called from invalid context" bug in
dev_pm_opp_init_cpufreq_table() from Stephen Boyd
- ACPI battery driver fix for a warning message added in 3.16 that
prints silly stuff sometimes from Mariusz Ceier
- Hibernation fix for safer handling of mismatches in the 820 memory
map between the configurations during image creation and during the
subsequent restore from Chun-Yi Lee
- ACPI processor driver fix to handle CPU hotplug notifications
correctly during system suspend/resume from Lan Tianyu
- Series of four cpuidle menu governor cleanups that also should
speed it up a bit from Mel Gorman
- Fixes for the speedstep-smi, integrator, cpu0 and arm_big_little
cpufreq drivers from Hans Wennborg, Himangi Saraogi, Markus
Pargmann and Uwe Kleine-König
- Version 3.0 of the analyze_suspend.py suspend profiling tool from
Todd E Brandt"
* tag 'pm+acpi-3.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI / battery: Fix warning message in acpi_battery_get_state()
PM / tools: analyze_suspend.py: update to v3.0
cpufreq: arm_big_little: fix module license spec
cpufreq: speedstep-smi: fix decimal printf specifiers
ACPI / hotplug: Check scan handlers in acpi_scan_hot_remove()
cpufreq: OPP: Avoid sleeping while atomic
cpufreq: cpu0: Do not print error message when deferring
cpufreq: integrator: Use set_cpus_allowed_ptr
PM / hibernate: avoid unsafe pages in e820 reserved regions
ACPI / processor: Make acpi_cpu_soft_notify() process CPU FROZEN events
cpuidle: menu: Lookup CPU runqueues less
cpuidle: menu: Call nr_iowait_cpu less times
cpuidle: menu: Use ktime_to_us instead of reinventing the wheel
cpuidle: menu: Use shifts when calculating averages where possible
Benjamin Herrenschmidt pointed out that I further missed modifying
update_vsyscall after the wall_to_mono value was changed to a
timespec64. This causes issues on powerpc32, which expects a 32bit
timespec.
This patch fixes the problem by properly converting from a timespec64 to
a timespec before passing the value on to the arch-specific vsyscall
logic.
[ Thomas is currently on vacation, but reviewed it and wanted me to send
this fix on to you directly. ]
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull more powerpc updates from Ben Herrenschmidt:
"Here are some more powerpc bits for 3.17, essentially fixes.
The biggest series, also aimed at -stable, is from Aneesh and is the
result of weeks and weeks of debugging to find out why the heck or THP
implementation was occasionally triggering multi-hit errors in our
level 1 TLB. It ended up being a combination of issues including
subtleties as to how we should invalidate those special 'MPSS' pages
we use to allow the use of 16M pages inside 4K/64K "base page size"
segments (you really have to love our MMU !)
Another interesting one in the "OMG" category is the series from
Michael adding memory barriers to spin_is_locked(). That's also the
result of many days of debugging to figure out why the semaphore code
would occasionally crash in ways that made no sense. It ended up
being some creative lock stacking that was defeated by the fact that
our locks allow a load inside the locked section to be re-ordered with
the load of the lock value itself (I'm still of two mind about whether
to kill that once and for all by putting a heavier barrier back into
our lock implementation...). The fixes come with a long explanation
in the cset comments, feel free to read it if you feel like having a
headache today"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (25 commits)
powerpc/thp: Add tracepoints to track hugepage invalidate
powerpc/mm: Use read barrier when creating real_pte
powerpc/thp: Use ACCESS_ONCE when loading pmdp
powerpc/thp: Invalidate with vpn in loop
powerpc/thp: Handle combo pages in invalidate
powerpc/thp: Invalidate old 64K based hash page mapping before insert of 4k pte
powerpc/thp: Don't recompute vsid and ssize in loop on invalidate
powerpc/thp: Add write barrier after updating the valid bit
powerpc: reorder per-cpu NUMA information's initialization
powerpc/perf/hv-24x7: Use kmem_cache_free
powerpc/pseries/hvcserver: Fix endian issue in hvcs_get_partner_info
powerpc: Hard disable interrupts in xmon
powerpc: remove duplicate definition of TEXASR_FS
powerpc/pseries: Avoid deadlock on removing ddw
powerpc/pseries: Failure on removing device node
powerpc/boot: Use correct zlib types for comparison
powerpc/powernv: Interface to register/unregister opal dump region
printk: Add function to return log buffer address and size
powerpc: Add POWER8 features to CPU_FTRS_POSSIBLE/ALWAYS
powerpc/ppc476: Disable BTAC
...
Pull seccomp fix from James Morris.
BUG(!spin_is_locked()) really doesn't work very well in UP
configurations without any actual spinlock state. Which is very much
why we have that "assert_spin_lock()" function for this.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
seccomp: Replace BUG(!spin_is_locked()) with assert_spin_lock
Unlike the original unfair rwlock implementation, queued rwlock
will grant lock according to the chronological sequence of the lock
requests except when the lock requester is in the interrupt context.
Consequently, recursive read_lock calls will now hang the process if
there is a write_lock call somewhere in between the read_lock calls.
This patch updates the lockdep implementation to look for recursive
read_lock calls. A new read state (3) is used to mark those read_lock
call that cannot be recursively called except in the interrupt
context. The new read state does exhaust the 2 bits available in
held_lock:read bit field. The addition of any new read state in the
future may require a redesign of how all those bits are squeezed
together in the held_lock structure.
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1407345722-61615-2-git-send-email-Waiman.Long@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
4badad35 ("locking/mutex: Disable optimistic spinning on some
architectures") added a ARCH_SUPPORTS_ATOMIC_RMW flag to
disable the mutex optimistic feature on specific archs.
Because CONFIG_MUTEX_SPIN_ON_OWNER only depended on DEBUG and
SMP, it was ok to have the ->owner field conditional a bit
flexible. However by adding a new variable to the matter,
we can waste space with the unused field, ie: CONFIG_SMP &&
(!CONFIG_MUTEX_SPIN_ON_OWNER && !CONFIG_DEBUG_MUTEX).
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Acked-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: aswin@hp.com
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/1406752916-3341-5-git-send-email-davidlohr@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When we fail to acquire the mutex in the fastpath, we end up calling
__mutex_lock_common(). A *lot* goes on in this function. Move out the
optimistic spinning code into mutex_optimistic_spin() and simplify
the former a bit. Furthermore, this is similar to what we have in
rwsems. No logical changes.
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Acked-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: aswin@hp.com
Cc: mingo@kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1406752916-3341-4-git-send-email-davidlohr@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When unlocking, we always want to reach the slowpath with the lock's counter
indicating it is unlocked. -- as returned by the asm fastpath call or by
explicitly setting it. While doing so, at least in theory, we can optimize
and allow faster lock stealing.
When unlocking, we always want to reach the slowpath with the lock's counter
indicating it is unlocked. -- as returned by the asm fastpath call or by
explicitly setting it. While doing so, at least in theory, we can optimize
and allow faster lock stealing.
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: jason.low2@hp.com
Cc: aswin@hp.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1406752916-3341-2-git-send-email-davidlohr@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Just how the locking-end behaves, when unlocking, go ahead and
obtain the proper data structure immediately after the previous
(asm-end) call exits and there are (probably) pending waiters.
This simplifies a bit some of the layering.
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: jason.low2@hp.com
Cc: aswin@hp.com
Cc: mingo@kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1406752916-3341-1-git-send-email-davidlohr@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Its been a while and there are no in-tree users left, so remove the
deprecated barriers.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chen, Gong <gong.chen@linux.intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Joe Perches <joe@perches.com>
Cc: John Sullivan <jsrhbz@kanargh.force9.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
One should first enqueue to the waitqueue and then check for the
condition. If the condition gets true after mutex_unlock() but before
poll_wait() then we lose it and would have wait for another wakeup.
This has been like this since v2.6.31-rc1 commit c7138f37f9 ("perf_counter:
fix perf_poll()"). Before that it was slightly worse. I guess we get enough
wakeups so if we miss here one it doesn't really matter. It is still a
bad example.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1407159068-1478-1-git-send-email-bigeasy@linutronix.de
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In cases when the owner task exits before the workload and the
workload made some forks, all the events stay in until the last
workload process exits. Thats' because each child event holds
parent reference.
We want to release all children events once the parent is gone,
because at that time there's no process to read them anyway, so
they're just eating resources.
This removal races with process exit, which removes all events
and fork, which clone events. To be clear of those two, adding
work queue to remove orphaned child for context in case such
event is detected.
Using delayed work queue (with delay == 1), because we queue this
work under perf scheduler callbacks. Normal work queue tries to wake
up the queue process, which deadlocks on rq->lock in this place.
Also preventing clones from abandoned parent event.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1406896382-18404-4-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Adding fake EVENT_OWNER_KERNEL owner pointer value for kernel perf
events, so we could distinguish it from user events, which needs
special care in following patch.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1406896382-18404-3-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Platforms like IBM Power Systems supports service processor
assisted dump. It provides interface to add memory region to
be captured when system is crashed.
During initialization/running we can add kernel memory region
to be collected.
Presently we don't have a way to get the log buffer base address
and size. This patch adds support to return log buffer address
and size.
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Commit a43455a1d5 ensures that
task_numa_migrate will call task_numa_compare on the preferred
node all the time, even when the preferred node has no free capacity.
This could lead to a performance regression if nr_running == capacity
on both the source and the destination node. This can be avoided by
also checking for nr_running == capacity on the source node, which is
one stricter than checking .has_free_capacity.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: mgorman@suse.de
Cc: vincent.guittot@linaro.org
Cc: Morten.Rasmussen@arm.com
Cc: nicolas.pitre@linaro.org
Cc: efault@gmx.de
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1407173008-9334-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The child variable in build_overlap_sched_groups() actually refers to the
peer or sibling domain of the given CPU. Rename it to sibling to be consistent
with the naming in build_group_mask().
Signed-off-by: Zhihui Zhang <zzhsuny@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1406942283-18249-1-git-send-email-zzhsuny@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Allow calculate_imbalance() to 'create' idle cpus in the busiest group
if there are idle cpus in the local group.
Suggested-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140729152705.GX12054@laptop.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently update_sd_pick_busiest only identifies the busiest sd
that is either overloaded, or has a group imbalance. When no
sd is imbalanced or overloaded, the load balancer fails to find
the busiest domain.
This breaks load balancing between domains that are not overloaded,
in the !SD_ASYM_PACKING case. This patch makes update_sd_pick_busiest
return true when the busiest sd yet is encountered.
Groups are ranked in the order overloaded > imbalanced > other,
with higher ranked groups getting priority even when their load
is lower. This is necessary due to the possibility of unequal
capacities and cpumasks between domains within a sched group.
Behaviour for SD_ASYM_PACKING does not seem to match the comment,
but I have no hardware to test that so I have left the behaviour
of that code unchanged.
Enum for group classification suggested by Peter Zijlstra.
Signed-off-by: Rik van Riel <riel@redhat.com>
[peterz: replaced sg_lb_stats::group_imb with the new enum group_type
in an attempt to avoid endless recalculation]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Acked-by: Michael Neuling <mikey@neuling.org>
Cc: ktkhai@parallels.com
Cc: tim.c.chen@linux.intel.com
Cc: nicolas.pitre@linaro.org
Cc: jhladky@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140729152743.GI3935@laptop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rik noticed that calculate_imbalance() relies on
update_sd_pick_busiest() to guarantee that busiest->sum_nr_running >
busiest->group_capacity_factor.
Break this implicit assumption (with the intent of not providing it
anymore) by having calculat_imbalance() verify it and not rely on
others.
Reported-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20140729152631.GW12054@laptop.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
* pm-sleep:
PM / hibernate: avoid unsafe pages in e820 reserved regions
* pm-cpufreq:
cpufreq: arm_big_little: fix module license spec
cpufreq: speedstep-smi: fix decimal printf specifiers
cpufreq: OPP: Avoid sleeping while atomic
cpufreq: cpu0: Do not print error message when deferring
cpufreq: integrator: Use set_cpus_allowed_ptr
* pm-cpuidle:
cpuidle: menu: Lookup CPU runqueues less
cpuidle: menu: Call nr_iowait_cpu less times
cpuidle: menu: Use ktime_to_us instead of reinventing the wheel
cpuidle: menu: Use shifts when calculating averages where possible
Current upstream kernel hangs with mips and powerpc targets in
uniprocessor mode if SECCOMP is configured.
Bisect points to commit dbd952127d ("seccomp: introduce writer locking").
Turns out that code such as
BUG_ON(!spin_is_locked(&list_lock));
can not be used in uniprocessor mode because spin_is_locked() always
returns false in this configuration, and that assert_spin_locked()
exists for that very purpose and must be used instead.
Fixes: dbd952127d ("seccomp: introduce writer locking")
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
Pull vfs updates from Al Viro:
"Stuff in here:
- acct.c fixes and general rework of mnt_pin mechanism. That allows
to go for delayed-mntput stuff, which will permit mntput() on deep
stack without worrying about stack overflows - fs shutdown will
happen on shallow stack. IOW, we can do Eric's umount-on-rmdir
series without introducing tons of stack overflows on new mntput()
call chains it introduces.
- Bruce's d_splice_alias() patches
- more Miklos' rename() stuff.
- a couple of regression fixes (stable fodder, in the end of branch)
and a fix for API idiocy in iov_iter.c.
There definitely will be another pile, maybe even two. I'd like to
get Eric's series in this time, but even if we miss it, it'll go right
in the beginning of for-next in the next cycle - the tricky part of
prereqs is in this pile"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits)
fix copy_tree() regression
__generic_file_write_iter(): fix handling of sync error after DIO
switch iov_iter_get_pages() to passing maximal number of pages
fs: mark __d_obtain_alias static
dcache: d_splice_alias should detect loops
exportfs: update Exporting documentation
dcache: d_find_alias needn't recheck IS_ROOT && DCACHE_DISCONNECTED
dcache: remove unused d_find_alias parameter
dcache: d_obtain_alias callers don't all want DISCONNECTED
dcache: d_splice_alias should ignore DCACHE_DISCONNECTED
dcache: d_splice_alias mustn't create directory aliases
dcache: close d_move race in d_splice_alias
dcache: move d_splice_alias
namei: trivial fix to vfs_rename_dir comment
VFS: allow ->d_manage() to declare -EISDIR in rcu_walk mode.
cifs: support RENAME_NOREPLACE
hostfs: support rename flags
shmem: support RENAME_EXCHANGE
shmem: support RENAME_NOREPLACE
btrfs: add RENAME_NOREPLACE
...
rarely ever hit, and requires the user to do something that users rarely
do. It took a few special test cases to even trigger this bug,
and one of them was just one test in the process of finishing up as another
one started.
Both bugs have to do with the ring buffer iterator rb_iter_peek(), but one
is more indirect than the other.
The fist bug fix is simply an increase in the safety net loop counter.
The counter makes sure that the rb_iter_peek() only iterates the number
of times we expect it can, and no more. Well, there was one way it could
iterate one more than we expected, and that caused the ring buffer
to shutdown with a nasty warning. The fix was simply to up that counter by
one.
The other bug has to be with rb_iter_reset() (called by rb_iter_peek()).
This happens when a user reads both the trace_pipe and trace files.
The trace_pipe is a consuming read and does not use the ring buffer
iterator, but the trace file is not a consuming read and does use the
ring buffer iterator. When the trace file is being read, if it detects
that a consuming read occurred, it resets the iterator and starts over.
But the reset code that does this (rb_iter_reset()), checks if the
reader_page is linked to the ring buffer or not, and will look into
the ring buffer itself if it is not. This is wrong, as it should always
try to read the reader page first. Not to mention, the code that looked
into the ring buffer did it wrong, and used the header_page "read" offset
to start reading on that page. That offset is bogus for pages in the
writable ring buffer, and was corrupting the iterator, and it would start
returning bogus events.
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Merge tag 'trace-fixes-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull trace file read iterator fixes from Steven Rostedt:
"This contains a fix for two long standing bugs. Both of which are
rarely ever hit, and requires the user to do something that users
rarely do. It took a few special test cases to even trigger this bug,
and one of them was just one test in the process of finishing up as
another one started.
Both bugs have to do with the ring buffer iterator rb_iter_peek(), but
one is more indirect than the other.
The fist bug fix is simply an increase in the safety net loop counter.
The counter makes sure that the rb_iter_peek() only iterates the
number of times we expect it can, and no more. Well, there was one
way it could iterate one more than we expected, and that caused the
ring buffer to shutdown with a nasty warning. The fix was simply to
up that counter by one.
The other bug has to be with rb_iter_reset() (called by
rb_iter_peek()). This happens when a user reads both the trace_pipe
and trace files. The trace_pipe is a consuming read and does not use
the ring buffer iterator, but the trace file is not a consuming read
and does use the ring buffer iterator. When the trace file is being
read, if it detects that a consuming read occurred, it resets the
iterator and starts over. But the reset code that does this
(rb_iter_reset()), checks if the reader_page is linked to the ring
buffer or not, and will look into the ring buffer itself if it is not.
This is wrong, as it should always try to read the reader page first.
Not to mention, the code that looked into the ring buffer did it
wrong, and used the header_page "read" offset to start reading on that
page. That offset is bogus for pages in the writable ring buffer, and
was corrupting the iterator, and it would start returning bogus
events"
* tag 'trace-fixes-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ring-buffer: Always reset iterator to reader page
ring-buffer: Up rb_iter_peek() loop count to 3
Pull namespace updates from Eric Biederman:
"This is a bunch of small changes built against 3.16-rc6. The most
significant change for users is the first patch which makes setns
drmatically faster by removing unneded rcu handling.
The next chunk of changes are so that "mount -o remount,.." will not
allow the user namespace root to drop flags on a mount set by the
system wide root. Aks this forces read-only mounts to stay read-only,
no-dev mounts to stay no-dev, no-suid mounts to stay no-suid, no-exec
mounts to stay no exec and it prevents unprivileged users from messing
with a mounts atime settings. I have included my test case as the
last patch in this series so people performing backports can verify
this change works correctly.
The next change fixes a bug in NFS that was discovered while auditing
nsproxy users for the first optimization. Today you can oops the
kernel by reading /proc/fs/nfsfs/{servers,volumes} if you are clever
with pid namespaces. I rebased and fixed the build of the
!CONFIG_NFS_FS case yesterday when a build bot caught my typo. Given
that no one to my knowledge bases anything on my tree fixing the typo
in place seems more responsible that requiring a typo-fix to be
backported as well.
The last change is a small semantic cleanup introducing
/proc/thread-self and pointing /proc/mounts and /proc/net at it. This
prevents several kinds of problemantic corner cases. It is a
user-visible change so it has a minute chance of causing regressions
so the change to /proc/mounts and /proc/net are individual one line
commits that can be trivially reverted. Unfortunately I lost and
could not find the email of the original reporter so he is not
credited. From at least one perspective this change to /proc/net is a
refgression fix to allow pthread /proc/net uses that were broken by
the introduction of the network namespace"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
proc: Point /proc/mounts at /proc/thread-self/mounts instead of /proc/self/mounts
proc: Point /proc/net at /proc/thread-self/net instead of /proc/self/net
proc: Implement /proc/thread-self to point at the directory of the current thread
proc: Have net show up under /proc/<tgid>/task/<tid>
NFS: Fix /proc/fs/nfsfs/servers and /proc/fs/nfsfs/volumes
mnt: Add tests for unprivileged remount cases that have found to be faulty
mnt: Change the default remount atime from relatime to the existing value
mnt: Correct permission checks in do_remount
mnt: Move the test for MNT_LOCK_READONLY from change_mount_flags into do_remount
mnt: Only change user settable mount flags in remount
namespaces: Use task_lock and not rcu to protect nsproxy
Pull arch signal handling cleanup from Richard Weinberger:
"This patch series moves all remaining archs to the get_signal(),
signal_setup_done() and sigsp() functions.
Currently these archs use open coded variants of the said functions.
Further, unused parameters get removed from get_signal_to_deliver(),
tracehook_signal_handler() and signal_delivered().
At the end of the day we save around 500 lines of code."
* 'signal-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc: (43 commits)
powerpc: Use sigsp()
openrisc: Use sigsp()
mn10300: Use sigsp()
mips: Use sigsp()
microblaze: Use sigsp()
metag: Use sigsp()
m68k: Use sigsp()
m32r: Use sigsp()
hexagon: Use sigsp()
frv: Use sigsp()
cris: Use sigsp()
c6x: Use sigsp()
blackfin: Use sigsp()
avr32: Use sigsp()
arm64: Use sigsp()
arc: Use sigsp()
sas_ss_flags: Remove nested ternary if
Rip out get_signal_to_deliver()
Clean up signal_delivered()
tracehook_signal_handler: Remove sig, info, ka and regs
...
Since commit 5d2acfc7b9 ("kconfig: make
allnoconfig disable options behind EMBEDDED and EXPERT") in 3.15-rc1,
"make allnoconfig" disables every possible config option.
However, a few configuration options (CC_OPTIMIZE_FOR_SIZE,
OPTIMIZE_INLINING) produce a smaller kernel when turned on, and a few
choices exist (compression, highmem, allocator) for which a non-default
option produces a smaller kernel.
Add a "tinyconfig" option, which starts from allnoconfig and then sets
these options to configure the tiniest possible kernel. This provides a
better baseline for embedded systems or efforts to reduce kernel size.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
This is the final piece of the puzzle of verifying kernel image signature
during kexec_file_load() syscall.
This patch calls into PE file routines to verify signature of bzImage. If
signature are valid, kexec_file_load() succeeds otherwise it fails.
Two new config options have been introduced. First one is
CONFIG_KEXEC_VERIFY_SIG. This option enforces that kernel has to be
validly signed otherwise kernel load will fail. If this option is not
set, no signature verification will be done. Only exception will be when
secureboot is enabled. In that case signature verification should be
automatically enforced when secureboot is enabled. But that will happen
when secureboot patches are merged.
Second config option is CONFIG_KEXEC_BZIMAGE_VERIFY_SIG. This option
enables signature verification support on bzImage. If this option is not
set and previous one is set, kernel image loading will fail because kernel
does not have support to verify signature of bzImage.
I tested these patches with both "pesign" and "sbsign" signed bzImages.
I used signing_key.priv key and signing_key.x509 cert for signing as
generated during kernel build process (if module signing is enabled).
Used following method to sign bzImage.
pesign
======
- Convert DER format cert to PEM format cert
openssl x509 -in signing_key.x509 -inform DER -out signing_key.x509.PEM -outform
PEM
- Generate a .p12 file from existing cert and private key file
openssl pkcs12 -export -out kernel-key.p12 -inkey signing_key.priv -in
signing_key.x509.PEM
- Import .p12 file into pesign db
pk12util -i /tmp/kernel-key.p12 -d /etc/pki/pesign
- Sign bzImage
pesign -i /boot/vmlinuz-3.16.0-rc3+ -o /boot/vmlinuz-3.16.0-rc3+.signed.pesign
-c "Glacier signing key - Magrathea" -s
sbsign
======
sbsign --key signing_key.priv --cert signing_key.x509.PEM --output
/boot/vmlinuz-3.16.0-rc3+.signed.sbsign /boot/vmlinuz-3.16.0-rc3+
Patch details:
Well all the hard work is done in previous patches. Now bzImage loader
has just call into that code and verify whether bzImage signature are
valid or not.
Also create two config options. First one is CONFIG_KEXEC_VERIFY_SIG.
This option enforces that kernel has to be validly signed otherwise kernel
load will fail. If this option is not set, no signature verification will
be done. Only exception will be when secureboot is enabled. In that case
signature verification should be automatically enforced when secureboot is
enabled. But that will happen when secureboot patches are merged.
Second config option is CONFIG_KEXEC_BZIMAGE_VERIFY_SIG. This option
enables signature verification support on bzImage. If this option is not
set and previous one is set, kernel image loading will fail because kernel
does not have support to verify signature of bzImage.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds support for loading a kexec on panic (kdump) kernel usning
new system call.
It prepares ELF headers for memory areas to be dumped and for saved cpu
registers. Also prepares the memory map for second kernel and limits its
boot to reserved areas only.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is loader specific code which can load bzImage and set it up for
64bit entry. This does not take care of 32bit entry or real mode entry.
32bit mode entry can be implemented if somebody needs it.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Load purgatory code in RAM and relocate it based on the location.
Relocation code has been inspired by module relocation code and purgatory
relocation code in kexec-tools.
Also compute the checksums of loaded kexec segments and store them in
purgatory.
Arch independent code provides this functionality so that arch dependent
bootloaders can make use of it.
Helper functions are provided to get/set symbol values in purgatory which
are used by bootloaders later to set things like stack and entry point of
second kernel etc.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Previous patch provided the interface definition and this patch prvides
implementation of new syscall.
Previously segment list was prepared in user space. Now user space just
passes kernel fd, initrd fd and command line and kernel will create a
segment list internally.
This patch contains generic part of the code. Actual segment preparation
and loading is done by arch and image specific loader. Which comes in
next patch.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the new syscall kexec_file_load() declaration/interface. I have
reserved the syscall number only for x86_64 so far. Other architectures
(including i386) can reserve syscall number when they enable the support
for this new syscall.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I have added two more functions to walk through resources.
Currently walk_system_ram_range() deals with pfn and /proc/iomem can
contain partial pages. By dealing in pfn, callback function loses the
info that last page of a memory range is a partial page and not the full
page. So I implemented walk_system_ram_res() which returns u64 values to
callback functions and now it properly return start and end address.
walk_system_ram_range() uses find_next_system_ram() to find the next ram
resource. This in turn only travels through siblings of top level child
and does not travers through all the nodes of the resoruce tree. I also
need another function where I can walk through all the resources, for
example figure out where "GART" aperture is. Figure out where ACPI memory
is.
So I wrote another function walk_iomem_res() which walks through all
/proc/iomem resources and returns matches as asked by caller. Caller can
specify "name" of resource, start and end and flags.
Got rid of find_next_system_ram_res() and instead implemented more generic
find_next_iomem_res() which can be used to traverse top level children
only based on an argument.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kimage_normal_alloc() and kimage_crash_alloc() are doing lot of similar
things and differ only little. So instead of having two separate
functions create a common function kimage_alloc_init() and pass it the
"flags" argument which tells whether it is normal kexec or kexec_on_panic.
And this function should be able to deal with both the cases.
This consolidation also helps later where we can use a common function
kimage_file_alloc_init() to handle normal and crash cases for new file
based kexec syscall.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Previously do_kimage_alloc() will allocate a kimage structure, copy
segment list from user space and then do the segment list sanity
verification.
Break down this function in 3 parts. do_kimage_alloc_init() to do actual
allocation and basic initialization of kimage structure.
copy_user_segment_list() to copy segment list from user space and
sanity_check_segment_list() to verify the sanity of segment list as passed
by user space.
In later patches, I need to only allocate kimage and not copy segment list
from user space. So breaking down in smaller functions enables re-use of
code at other places.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let's use the more common "unusable".
This patch was originally written and posted by Boris. I am including it
in this patch series.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch series does not do kernel signature verification yet. I plan
to post another patch series for that. Now distributions are already
signing PE/COFF bzImage with PKCS7 signature I plan to parse and verify
those signatures.
Primary goal of this patchset is to prepare groundwork so that kernel
image can be signed and signatures be verified during kexec load. This
should help with two things.
- It should allow kexec/kdump on secureboot enabled machines.
- In general it can help even without secureboot. By being able to verify
kernel image signature in kexec, it should help with avoiding module
signing restrictions. Matthew Garret showed how to boot into a custom
kernel, modify first kernel's memory and then jump back to old kernel and
bypass any policy one wants to.
This patch (of 15):
Kexec wants to use bin2c and it wants to use it really early in the build
process. See arch/x86/purgatory/ code in later patches.
So move bin2c in scripts/basic so that it can be built very early and
be usable by arch/x86/purgatory/
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memfd_create() is similar to mmap(MAP_ANON), but returns a file-descriptor
that you can pass to mmap(). It can support sealing and avoids any
connection to user-visible mount-points. Thus, it's not subject to quotas
on mounted file-systems, but can be used like malloc()'ed memory, but with
a file-descriptor to it.
memfd_create() returns the raw shmem file, so calls like ftruncate() can
be used to modify the underlying inode. Also calls like fstat() will
return proper information and mark the file as regular file. If you want
sealing, you can specify MFD_ALLOW_SEALING. Otherwise, sealing is not
supported (like on all other regular files).
Compared to O_TMPFILE, it does not require a tmpfs mount-point and is not
subject to a filesystem size limit. It is still properly accounted to
memcg limits, though, and to the same overcommit or no-overcommit
accounting as all user memory.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Ryan Lortie <desrt@desrt.ca>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Daniel Mack <zonque@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch (of 6):
The i_mmap_writable field counts existing writable mappings of an
address_space. To allow drivers to prevent new writable mappings, make
this counter signed and prevent new writable mappings if it is negative.
This is modelled after i_writecount and DENYWRITE.
This will be required by the shmem-sealing infrastructure to prevent any
new writable mappings after the WRITE seal has been set. In case there
exists a writable mapping, this operation will fail with EBUSY.
Note that we rely on the fact that iff you already own a writable mapping,
you can increase the counter without using the helpers. This is the same
that we do for i_writecount.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Ryan Lortie <desrt@desrt.ca>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Daniel Mack <zonque@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is small set of patches our team has had kicking around for a few
versions internally that fixes tasks getting hung on shm_exit when there
are many threads hammering it at once.
Anton wrote a simple test to cause the issue:
http://ozlabs.org/~anton/junkcode/bust_shm_exit.c
Before applying this patchset, this test code will cause either hanging
tracebacks or pthread out of memory errors.
After this patchset, it will still produce output like:
root@somehost:~# ./bust_shm_exit 1024 160
...
INFO: rcu_sched detected stalls on CPUs/tasks: {} (detected by 116, t=2111 jiffies, g=241, c=240, q=7113)
INFO: Stall ended before state dump start
...
But the task will continue to run along happily, so we consider this an
improvement over hanging, even if it's a bit noisy.
This patch (of 3):
exit_shm obtains the ipc_ns shm rwsem for write and holds it while it
walks every shared memory segment in the namespace. Thus the amount of
work is related to the number of shm segments in the namespace not the
number of segments that might need to be cleaned.
In addition, this occurs after the task has been notified the thread has
exited, so the number of tasks waiting for the ns shm rwsem can grow
without bound until memory is exausted.
Add a list to the task struct of all shmids allocated by this task. Init
the list head in copy_process. Use the ns->rwsem for locking. Add
segments after id is added, remove before removing from id.
On unshare of NEW_IPCNS orphan any ids as if the task had exited, similar
to handling of semaphore undo.
I chose a define for the init sequence since its a simple list init,
otherwise it would require a function call to avoid include loops between
the semaphore code and the task struct. Converting the list_del to
list_del_init for the unshare cases would remove the exit followed by
init, but I left it blow up if not inited.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Jack Miller <millerjo@us.ibm.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This taint flag will be set if the system has ever entered a softlockup
state. Similar to TAINT_WARN it is useful to know whether or not the
system has been in a softlockup state when debugging.
[akpm@linux-foundation.org: apply the taint before calling panic()]
Signed-off-by: Josh Hunt <johunt@akamai.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes checkpatch warning:
WARNING: debugfs_remove(NULL) is safe this check is probably not required
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's only used in fork.c:mm_init().
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a forking process has a thread calling (un)mmap (silly but still),
the child process may have some of its mm's vm usage counters (total_vm
and friends) screwed up, because currently they are copied from oldmm
w/o holding any locks (memcpy in dup_mm).
This patch moves the counters initialization to dup_mmap() to be called
under oldmm->mmap_sem, which eliminates any possibility of race.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm->pinned_vm counts pages of mm's address space that were permanently
pinned in memory by increasing their reference counter. The counter was
introduced by commit bc3e53f682 ("mm: distinguish between mlocked and
pinned pages"), while before it locked_vm had been used for such pages.
Obviously, we should reset the counter on fork if !CLONE_VM, just like
we do with locked_vm, but currently we don't. Let's fix it.
This patch will fix the contents of /proc/pid/status:VmPin.
ib_umem_get[infiniband] and perf_mmap still check pinned_vm against
RLIMIT_MEMLOCK. It's left from the times when pinned pages were accounted
under locked_vm, but today it looks wrong. It isn't clear how we should
deal with it.
We still have some drivers accounting pinned pages under mm->locked_vm -
this is what commit bc3e53f682 was fighting against. It's
infiniband/usnic and vfio.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Roland Dreier <roland@kernel.org>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm initialization on fork/exec is spread all over the place, which makes
the code look inconsistent.
We have mm_init(), which is supposed to init/nullify mm's internals, but
it doesn't init all the fields it should:
- on fork ->mmap,mm_rb,vmacache_seqnum,map_count,mm_cpumask,locked_vm
are zeroed in dup_mmap();
- on fork ->pmd_huge_pte is zeroed in dup_mm(), immediately before
calling mm_init();
- ->cpu_vm_mask_var ptr is initialized by mm_init_cpumask(), which is
called before mm_init() on both fork and exec;
- ->context is initialized by init_new_context(), which is called after
mm_init() on both fork and exec;
Let's consolidate all the initializations in mm_init() to make the code
look cleaner.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
proc_uid_seq_operations, proc_gid_seq_operations and
proc_projid_seq_operations are only called in proc_id_map_open with
seq_open as const struct seq_operations so we can constify the 3
structures and update proc_id_map_open prototype.
text data bss dec hex filename
6817 404 1984 9205 23f5 kernel/user_namespace.o-before
6913 308 1984 9205 23f5 kernel/user_namespace.o-after
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__sprint_symbol() should restore original address when kallsyms_lookup()
failed to find a symbol. It's reported when dumpstack shows an address in
a dynamically allocated trampoline for ftrace.
[ 1314.612287] [<ffffffff81700312>] dump_stack+0x45/0x56
[ 1314.612290] [<ffffffff8125f5b0>] ? meminfo_proc_open+0x30/0x30
[ 1314.612293] [<ffffffffa080a494>] kpatch_ftrace_handler+0x14/0xf0 [kpatch]
[ 1314.612306] [<ffffffffa00160c4>] 0xffffffffa00160c3
You can see a difference in the hex address - c4 and c3. Fix it.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Reported-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's not used anywhere today, so let's remove it.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pages are now uncharged at release time, and all sources of batched
uncharges operate on lists of pages. Directly use those lists, and
get rid of the per-task batching state.
This also batches statistics accounting, in addition to the res
counter charges, to reduce IRQ-disabling and re-enabling.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These patches rework memcg charge lifetime to integrate more naturally
with the lifetime of user pages. This drastically simplifies the code and
reduces charging and uncharging overhead. The most expensive part of
charging and uncharging is the page_cgroup bit spinlock, which is removed
entirely after this series.
Here are the top-10 profile entries of a stress test that reads a 128G
sparse file on a freshly booted box, without even a dedicated cgroup (i.e.
executing in the root memcg). Before:
15.36% cat [kernel.kallsyms] [k] copy_user_generic_string
13.31% cat [kernel.kallsyms] [k] memset
11.48% cat [kernel.kallsyms] [k] do_mpage_readpage
4.23% cat [kernel.kallsyms] [k] get_page_from_freelist
2.38% cat [kernel.kallsyms] [k] put_page
2.32% cat [kernel.kallsyms] [k] __mem_cgroup_commit_charge
2.18% kswapd0 [kernel.kallsyms] [k] __mem_cgroup_uncharge_common
1.92% kswapd0 [kernel.kallsyms] [k] shrink_page_list
1.86% cat [kernel.kallsyms] [k] __radix_tree_lookup
1.62% cat [kernel.kallsyms] [k] __pagevec_lru_add_fn
After:
15.67% cat [kernel.kallsyms] [k] copy_user_generic_string
13.48% cat [kernel.kallsyms] [k] memset
11.42% cat [kernel.kallsyms] [k] do_mpage_readpage
3.98% cat [kernel.kallsyms] [k] get_page_from_freelist
2.46% cat [kernel.kallsyms] [k] put_page
2.13% kswapd0 [kernel.kallsyms] [k] shrink_page_list
1.88% cat [kernel.kallsyms] [k] __radix_tree_lookup
1.67% cat [kernel.kallsyms] [k] __pagevec_lru_add_fn
1.39% kswapd0 [kernel.kallsyms] [k] free_pcppages_bulk
1.30% cat [kernel.kallsyms] [k] kfree
As you can see, the memcg footprint has shrunk quite a bit.
text data bss dec hex filename
37970 9892 400 48262 bc86 mm/memcontrol.o.old
35239 9892 400 45531 b1db mm/memcontrol.o
This patch (of 4):
The memcg charge API charges pages before they are rmapped - i.e. have an
actual "type" - and so every callsite needs its own set of charge and
uncharge functions to know what type is being operated on. Worse,
uncharge has to happen from a context that is still type-specific, rather
than at the end of the page's lifetime with exclusive access, and so
requires a lot of synchronization.
Rewrite the charge API to provide a generic set of try_charge(),
commit_charge() and cancel_charge() transaction operations, much like
what's currently done for swap-in:
mem_cgroup_try_charge() attempts to reserve a charge, reclaiming
pages from the memcg if necessary.
mem_cgroup_commit_charge() commits the page to the charge once it
has a valid page->mapping and PageAnon() reliably tells the type.
mem_cgroup_cancel_charge() aborts the transaction.
This reduces the charge API and enables subsequent patches to
drastically simplify uncharging.
As pages need to be committed after rmap is established but before they
are added to the LRU, page_add_new_anon_rmap() must stop doing LRU
additions again. Revive lru_cache_add_active_or_unevictable().
[hughd@google.com: fix shmem_unuse]
[hughd@google.com: Add comments on the private use of -EAGAIN]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Skip kretprobe hit in NMI context, because if an NMI happens
inside the critical section protected by kretprobe_table.lock
and another(or same) kretprobe hit, pre_kretprobe_handler
tries to lock kretprobe_table.lock again.
Normal interrupts have no problem because they are disabled
with the lock.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20140804031016.11433.65539.stgit@kbuild-fedora.novalocal
[ Minor edits for clarity. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rather than playing silly buggers with vfsmount refcounts, just have
acct_on() ask fs/namespace.c for internal clone of file->f_path.mnt
and replace it with said clone. Then attach the pin to original
vfsmount. Voila - the clone will be alive until the file gets closed,
making sure that underlying superblock remains active, etc., and
we can drop the original vfsmount, so that it's not kept busy.
If the file lives until the final mntput of the original vfsmount,
we'll notice that there's an fs_pin (one in bsd_acct_struct that
holds that file) and mnt_pin_kill() will take it out. Since
->kill() is synchronous, we won't proceed past that point until
these files are closed (and private clones of our vfsmount are
gone), so we get the same ordering warranties we used to get.
mnt_pin()/mnt_unpin()/->mnt_pinned is gone now, and good riddance -
it never became usable outside of kernel/acct.c (and racy wrt
umount even there).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add a new field to fs_pin - kill(pin). That's what umount and r/o remount
will be calling for all pins attached to vfsmount and superblock resp.
Called after bumping the refcount, so it won't go away under us. Dropping
the refcount is responsibility of the instance. All generic stuff moved to
fs/fs_pin.c; the next step will rip all the knowledge of kernel/acct.c from
fs/super.c and fs/namespace.c. After that - death to mnt_pin(); it was
intended to be usable as generic mechanism for code that wants to attach
objects to vfsmount, so that they would not make the sucker busy and
would get killed on umount. Never got it right; it remained acct.c-specific
all along. Now it's very close to being killable.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
pull generic parts into struct fs_pin. Eventually we want those
to replace mnt_pin()/mnt_unpin() mess; that stuff will move to
fs/*.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* make acct->count atomic and acct freeing - rcu-delayed.
* instead of grabbing acct_lock around the places where we take a reference,
do that under rcu_read_lock() with atomic_long_inc_not_zero().
* have the new acct locked before making ns->bacct point to it
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Put these suckers on per-vfsmount and per-superblock lists instead.
Note: right now it's still acct_lock for everything, but that's
going to change.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
a) file can't be NULL
b) file can't be changed under us
c) all writes are serialized by acct->lock; no need to mess with
spinlock there.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Do not reuse bsd_acct_struct after closing the damn thing.
Structure lifetime is controlled by refcount now. We also
have a mutex in there, held over closing and writing (the
file is O_APPEND, so we are not losing any concurrency).
As the result, we do not need to bother with get_file()/fput()
on log write anymore. Moreover, do_acct_process() only needs
acct itself; file and pidns are picked from it.
Killed instances are distinguished by having NULL ->ns.
Refcount is protected by acct_lock; anybody taking the
mutex needs to grab a reference first.
The things will get a lot simpler in the next commits - this
is just the minimal chunk switching to the new lifetime rules.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There was an amusing bogosity in ac_rw calculation - it tried to
do encode_comp_t(encode_comp_t(0) / 1024). Seeing that comp_t is
a 3-bit exponent + 13-bit mantissa... it's a good thing that 0 is
represented by all-bits-clear.
The history of that one is interesting - it was introduced in
2.1.68pre1, when acct.c had been reworked and moved to separate
file. Two months later (2.1.86) somebody has noticed that the
sucker won't compile - there was no task_struct::io_usage.
At which point the ac_io calculation had changed from
encode_comp_t(current->io_usage) to encode_comp_t(0) and the
bug in the next line (absolutely real back then, had it ever
managed to compile) become a harmless bogosity. Looks like
nobody has ever noticed until now.
Anyway, let's bury that idiocy now that it got noticed. 17 years
is long enough...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Merge incoming from Andrew Morton:
- Various misc things.
- arch/sh updates.
- Part of ocfs2. Review is slow.
- Slab updates.
- Most of -mm.
- printk updates.
- lib/ updates.
- checkpatch updates.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (226 commits)
checkpatch: update $declaration_macros, add uninitialized_var
checkpatch: warn on missing spaces in broken up quoted
checkpatch: fix false positives for --strict "space after cast" test
checkpatch: fix false positive MISSING_BREAK warnings with --file
checkpatch: add test for native c90 types in unusual order
checkpatch: add signed generic types
checkpatch: add short int to c variable types
checkpatch: add for_each tests to indentation and brace tests
checkpatch: fix brace style misuses of else and while
checkpatch: add --fix option for a couple OPEN_BRACE misuses
checkpatch: use the correct indentation for which()
checkpatch: add fix_insert_line and fix_delete_line helpers
checkpatch: add ability to insert and delete lines to patch/file
checkpatch: add an index variable for fixed lines
checkpatch: warn on break after goto or return with same tab indentation
checkpatch: emit a warning on file add/move/delete
checkpatch: add test for commit id formatting style in commit log
checkpatch: emit fewer kmalloc_array/kcalloc conversion warnings
checkpatch: improve "no space after cast" test
checkpatch: allow multiple const * types
...
- ACPICA update to upstream version 20140724. That includes
ACPI 5.1 material (support for the _CCA and _DSD predefined names,
changes related to the DMAR and PCCT tables and ARM support among
other things) and cleanups related to using ACPICA's header files.
A major part of it is related to acpidump and the core code used
by that utility. Changes from Bob Moore, David E Box, Lv Zheng,
Sascha Wildner, Tomasz Nowicki, Hanjun Guo.
- Radix trees for memory bitmaps used by the hibernation core from
Joerg Roedel.
- Support for waking up the system from suspend-to-idle (also known
as the "freeze" sleep state) using ACPI-based PCI wakeup signaling
(Rafael J Wysocki).
- Fixes for issues related to ACPI button events (Rafael J Wysocki).
- New device ID for an ACPI-enumerated device included into the
Wildcat Point PCH from Jie Yang.
- ACPI video updates related to backlight handling from Hans de Goede
and Linus Torvalds.
- Preliminary changes needed to support ACPI on ARM from Hanjun Guo
and Graeme Gregory.
- ACPI PNP core cleanups from Arjun Sreedharan and Zhang Rui.
- Cleanups related to ACPI_COMPANION() and ACPI_HANDLE() macros
(Rafael J Wysocki).
- ACPI-based device hotplug cleanups from Wei Yongjun and
Rafael J Wysocki.
- Cleanups and improvements related to system suspend from
Lan Tianyu, Randy Dunlap and Rafael J Wysocki.
- ACPI battery cleanup from Wei Yongjun.
- cpufreq core fixes from Viresh Kumar.
- Elimination of a deadband effect from the cpufreq ondemand
governor and intel_pstate driver cleanups from Stratos Karafotis.
- 350MHz CPU support for the powernow-k6 cpufreq driver from
Mikulas Patocka.
- Fix for the imx6 cpufreq driver from Anson Huang.
- cpuidle core and governor cleanups from Daniel Lezcano,
Sandeep Tripathy and Mohammad Merajul Islam Molla.
- Build fix for the big_little cpuidle driver from Sachin Kamat.
- Configuration fix for the Operation Performance Points (OPP)
framework from Mark Brown.
- APM cleanup from Jean Delvare.
- cpupower utility fixes and cleanups from Peter Senna Tschudin,
Andrey Utkin, Himangi Saraogi, Rickard Strandqvist, Thomas Renninger.
/
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Merge tag 'pm+acpi-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management updates from Rafael Wysocki:
"Again, ACPICA leads the pack (47 commits), followed by cpufreq (18
commits) and system suspend/hibernation (9 commits).
From the new code perspective, the ACPICA update brings ACPI 5.1 to
the table, including a new device configuration object called _DSD
(Device Specific Data) that will hopefully help us to operate device
properties like Device Trees do (at least to some extent) and changes
related to supporting ACPI on ARM.
Apart from that we have hibernation changes making it use radix trees
to store memory bitmaps which should speed up some operations carried
out by it quite significantly. We also have some power management
changes related to suspend-to-idle (the "freeze" sleep state) support
and more preliminary changes needed to support ACPI on ARM (outside of
ACPICA).
The rest is fixes and cleanups pretty much everywhere.
Specifics:
- ACPICA update to upstream version 20140724. That includes ACPI 5.1
material (support for the _CCA and _DSD predefined names, changes
related to the DMAR and PCCT tables and ARM support among other
things) and cleanups related to using ACPICA's header files. A
major part of it is related to acpidump and the core code used by
that utility. Changes from Bob Moore, David E Box, Lv Zheng,
Sascha Wildner, Tomasz Nowicki, Hanjun Guo.
- Radix trees for memory bitmaps used by the hibernation core from
Joerg Roedel.
- Support for waking up the system from suspend-to-idle (also known
as the "freeze" sleep state) using ACPI-based PCI wakeup signaling
(Rafael J Wysocki).
- Fixes for issues related to ACPI button events (Rafael J Wysocki).
- New device ID for an ACPI-enumerated device included into the
Wildcat Point PCH from Jie Yang.
- ACPI video updates related to backlight handling from Hans de Goede
and Linus Torvalds.
- Preliminary changes needed to support ACPI on ARM from Hanjun Guo
and Graeme Gregory.
- ACPI PNP core cleanups from Arjun Sreedharan and Zhang Rui.
- Cleanups related to ACPI_COMPANION() and ACPI_HANDLE() macros
(Rafael J Wysocki).
- ACPI-based device hotplug cleanups from Wei Yongjun and Rafael J
Wysocki.
- Cleanups and improvements related to system suspend from Lan
Tianyu, Randy Dunlap and Rafael J Wysocki.
- ACPI battery cleanup from Wei Yongjun.
- cpufreq core fixes from Viresh Kumar.
- Elimination of a deadband effect from the cpufreq ondemand governor
and intel_pstate driver cleanups from Stratos Karafotis.
- 350MHz CPU support for the powernow-k6 cpufreq driver from Mikulas
Patocka.
- Fix for the imx6 cpufreq driver from Anson Huang.
- cpuidle core and governor cleanups from Daniel Lezcano, Sandeep
Tripathy and Mohammad Merajul Islam Molla.
- Build fix for the big_little cpuidle driver from Sachin Kamat.
- Configuration fix for the Operation Performance Points (OPP)
framework from Mark Brown.
- APM cleanup from Jean Delvare.
- cpupower utility fixes and cleanups from Peter Senna Tschudin,
Andrey Utkin, Himangi Saraogi, Rickard Strandqvist, Thomas
Renninger"
* tag 'pm+acpi-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (118 commits)
ACPI / LPSS: add LPSS device for Wildcat Point PCH
ACPI / PNP: Replace faulty is_hex_digit() by isxdigit()
ACPICA: Update version to 20140724.
ACPICA: ACPI 5.1: Update for PCCT table changes.
ACPICA/ARM: ACPI 5.1: Update for GTDT table changes.
ACPICA/ARM: ACPI 5.1: Update for MADT changes.
ACPICA/ARM: ACPI 5.1: Update for FADT changes.
ACPICA: ACPI 5.1: Support for the _CCA predifined name.
ACPICA: ACPI 5.1: New notify value for System Affinity Update.
ACPICA: ACPI 5.1: Support for the _DSD predefined name.
ACPICA: Debug object: Add current value of Timer() to debug line prefix.
ACPICA: acpihelp: Add UUID support, restructure some existing files.
ACPICA: Utilities: Fix local printf issue.
ACPICA: Tables: Update for DMAR table changes.
ACPICA: Remove some extraneous printf arguments.
ACPICA: Update for comments/formatting. No functional changes.
ACPICA: Disassembler: Add support for the ToUUID opererator (macro).
ACPICA: Remove a redundant cast to acpi_size for ACPI_OFFSET() macro.
ACPICA: Work around an ancient GCC bug.
ACPI / processor: Make it possible to get local x2apic id via _MAT
...
This patch set consists of the usual driver updates (ufs, storvsc, pm8001
hpsa). It also has removal of the user space target driver code (everyone is
using LIO now), a partial PCI MSI-X update, more multi-queue updates,
conversion to 64 bit LUNs (so we could theoretically cope with any LUN
returned by a device) and placeholder support for the ZBC device type (Shingle
drives), plus an assortment of minor updates and bug fixes.
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI updates from James Bottomley:
"This patch set consists of the usual driver updates (ufs, storvsc,
pm8001 hpsa). It also has removal of the user space target driver
code (everyone is using LIO now), a partial PCI MSI-X update, more
multi-queue updates, conversion to 64 bit LUNs (so we could
theoretically cope with any LUN returned by a device) and placeholder
support for the ZBC device type (Shingle drives), plus an assortment
of minor updates and bug fixes"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (143 commits)
scsi: do not issue SCSI RSOC command to Promise Vtrak E610f
vmw_pvscsi: Use pci_enable_msix_exact() instead of pci_enable_msix()
pm8001: Fix invalid return when request_irq() failed
lpfc: Remove superfluous call to pci_disable_msix()
isci: Use pci_enable_msix_exact() instead of pci_enable_msix()
bfa: Use pci_enable_msix_exact() instead of pci_enable_msix()
bfa: Cleanup bfad_setup_intr() function
bfa: Do not call pci_enable_msix() after it failed once
fnic: Use pci_enable_msix_exact() instead of pci_enable_msix()
scsi: use short driver name for per-driver cmd slab caches
scsi_debug: support scsi-mq, queues and locks
Drivers: add blist flags
scsi: ufs: fix endianness sparse warnings
scsi: ufs: make undeclared functions static
bnx2i: Update driver version to 2.7.10.1
pm8001: fix a memory leak in nvmd_resp
pm8001: fix update_flash
pm8001: fix a memory leak in flash_update
pm8001: Cleaning up uninitialized variables
pm8001: Fix to remove null pointer checks that could never happen
...
We need interrupts disabled when calling console_trylock_for_printk()
only so that cpu id we pass to can_use_console() remains valid (for
other things console_sem provides all the exclusion we need and
deadlocks on console_sem due to interrupts are impossible because we use
down_trylock()). However if we are rescheduled, we are guaranteed to
run on an online cpu so we can easily just get the cpu id in
can_use_console().
We can lose a bit of performance when we enable interrupts in
vprintk_emit() and then disable them again in console_unlock() but OTOH
it can somewhat reduce interrupt latency caused by console_unlock().
We differ from (reverted) commit 939f04bec1 in that we avoid calling
console_unlock() from vprintk_emit() with lockdep enabled as that has
unveiled quite some bugs leading to system freezes during boot (e.g.
https://lkml.org/lkml/2014/5/30/242,
https://lkml.org/lkml/2014/6/28/521).
Signed-off-by: Jan Kara <jack@suse.cz>
Tested-by: Andreas Bombe <aeb@debian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some small cleanups to kernel/printk/printk.c. None of them should
cause any change in behavior.
- When CONFIG_PRINTK is defined, parenthesize the value of LOG_LINE_MAX.
- When CONFIG_PRINTK is *not* defined, there is an extra LOG_LINE_MAX
definition; delete it.
- Pull an assignment out of a conditional expression in console_setup().
- Use isdigit() in console_setup() rather than open coding it.
- In update_console_cmdline(), drop a NUL-termination assignment;
the strlcpy() call that precedes it guarantees it's not needed.
- Simplify some logic in printk_timed_ratelimit().
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jan Kara <jack@suse.cz>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the IS_ENABLED() macro rather than #ifdef blocks to set certain
global values.
Signed-off-by: Alex Elder <elder@linaro.org>
Acked-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a few comments that don't accurately describe their corresponding
code. It also fixes some minor typographical errors.
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jan Kara <jack@suse.cz>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit a8fe19ebfb ("kernel/printk: use symbolic defines for console
loglevels") makes consistent use of symbolic values for printk() log
levels.
The naming scheme used is different from the one used for
DEFAULT_MESSAGE_LOGLEVEL though. Change that symbol name to be
MESSAGE_LOGLEVEL_DEFAULT for consistency. And because the value of that
symbol comes from a similarly-named config option, rename
CONFIG_DEFAULT_MESSAGE_LOGLEVEL as well.
Signed-off-by: Alex Elder <elder@linaro.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jan Kara <jack@suse.cz>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In do_syslog() there's a path used by kmsg_poll() and kmsg_read() that
only needs to know whether there's any data available to read (and not
its size). These callers only check for non-zero return. As a
shortcut, do_syslog() returns the difference between what has been
logged and what has been "seen."
The comments say that the "count of records" should be returned but it's
not. Instead it returns (log_next_idx - syslog_idx), which is a
difference between buffer offsets--and the result could be negative.
The behavior is the same (it'll be zero or not in the same cases), but
the count of records is more meaningful and it matches what the comments
say. So change the code to return that.
Signed-off-by: Alex Elder <elder@linaro.org>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The default size of the ring buffer is too small for machines with a
large amount of CPUs under heavy load. What ends up happening when
debugging is the ring buffer overlaps and chews up old messages making
debugging impossible unless the size is passed as a kernel parameter.
An idle system upon boot up will on average spew out only about one or
two extra lines but where this really matters is on heavy load and that
will vary widely depending on the system and environment.
There are mechanisms to help increase the kernel ring buffer for tracing
through debugfs, and those interfaces even allow growing the kernel ring
buffer per CPU. We also have a static value which can be passed upon
boot. Relying on debugfs however is not ideal for production, and
relying on the value passed upon bootup is can only used *after* an
issue has creeped up. Instead of being reactive this adds a proactive
measure which lets you scale the amount of contributions you'd expect to
the kernel ring buffer under load by each CPU in the worst case
scenario.
We use num_possible_cpus() to avoid complexities which could be
introduced by dynamically changing the ring buffer size at run time,
num_possible_cpus() lets us use the upper limit on possible number of
CPUs therefore avoiding having to deal with hotplugging CPUs on and off.
This introduces the kernel configuration option LOG_CPU_MAX_BUF_SHIFT
which is used to specify the maximum amount of contributions to the
kernel ring buffer in the worst case before the kernel ring buffer flips
over, the size is specified as a power of 2. The total amount of
contributions made by each CPU must be greater than half of the default
kernel ring buffer size (1 << LOG_BUF_SHIFT bytes) in order to trigger
an increase upon bootup. The kernel ring buffer is increased to the
next power of two that would fit the required minimum kernel ring buffer
size plus the additional CPU contribution. For example if LOG_BUF_SHIFT
is 18 (256 KB) you'd require at least 128 KB contributions by other CPUs
in order to trigger an increase of the kernel ring buffer. With a
LOG_CPU_BUF_SHIFT of 12 (4 KB) you'd require at least anything over > 64
possible CPUs to trigger an increase. If you had 128 possible CPUs the
amount of minimum required kernel ring buffer bumps to:
((1 << 18) + ((128 - 1) * (1 << 12))) / 1024 = 764 KB
Since we require the ring buffer to be a power of two the new required
size would be 1024 KB.
This CPU contributions are ignored when the "log_buf_len" kernel
parameter is used as it forces the exact size of the ring buffer to an
expected power of two value.
[pmladek@suse.cz: fix build]
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.cz>
Tested-by: Davidlohr Bueso <davidlohr@hp.com>
Tested-by: Petr Mladek <pmladek@suse.cz>
Reviewed-by: Davidlohr Bueso <davidlohr@hp.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: Arun KS <arunks.linux@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In practice the power of 2 practice of the size of the kernel ring
buffer remains purely historical but not a requirement, specially now
that we have LOG_ALIGN and use it for both static and dynamic
allocations. It could have helped with implicit alignment back in the
days given the even the dynamically sized ring buffer was guaranteed to
be aligned so long as CONFIG_LOG_BUF_SHIFT was set to produce a
__LOG_BUF_LEN which is architecture aligned, since log_buf_len=n would
be allowed only if it was > __LOG_BUF_LEN and we always ended up
rounding the log_buf_len=n to the next power of 2 with
roundup_pow_of_two(), any multiple of 2 then should be also architecture
aligned. These assumptions of course relied heavily on
CONFIG_LOG_BUF_SHIFT producing an aligned value but users can always
change this.
We now have precise alignment requirements set for the log buffer size
for both static and dynamic allocations, but lets upkeep the old
practice of using powers of 2 for its size to help with easy expected
scalable values and the allocators for dynamic allocations. We'll reuse
this later so move this into a helper.
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: Arun KS <arunks.linux@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have to consider alignment for the ring buffer both for the default
static size, and then also for when an dynamic allocation is made when
the log_buf_len=n kernel parameter is passed to set the size
specifically to a size larger than the default size set by the
architecture through CONFIG_LOG_BUF_SHIFT.
The default static kernel ring buffer can be aligned properly if
architectures set CONFIG_LOG_BUF_SHIFT properly, we provide ranges for
the size though so even if CONFIG_LOG_BUF_SHIFT has a sensible aligned
value it can be reduced to a non aligned value. Commit 6ebb017de9
("printk: Fix alignment of buf causing crash on ARM EABI") by Andrew
Lunn ensures the static buffer is always aligned and the decision of
alignment is done by the compiler by using __alignof__(struct log).
When log_buf_len=n is used we allocate the ring buffer dynamically.
Dynamic allocation varies, for the early allocation called before
setup_arch() memblock_virt_alloc() requests a page aligment and for the
default kernel allocation memblock_virt_alloc_nopanic() requests no
special alignment, which in turn ends up aligning the allocation to
SMP_CACHE_BYTES, which is L1 cache aligned.
Since we already have the required alignment for the kernel ring buffer
though we can do better and request explicit alignment for LOG_ALIGN.
This does that to be safe and make dynamic allocation alignment
explicit.
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Tested-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Petr Mladek <pmladek@suse.cz>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: Arun KS <arunks.linux@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The oom killer scans each process and determines whether it is eligible
for oom kill or whether the oom killer should abort because of
concurrent memory freeing. It will abort when an eligible process is
found to have TIF_MEMDIE set, meaning it has already been oom killed and
we're waiting for it to exit.
Processes with task->mm == NULL should not be considered because they
are either kthreads or have already detached their memory and killing
them would not lead to memory freeing. That memory is only freed after
exit_mm() has returned, however, and not when task->mm is first set to
NULL.
Clear TIF_MEMDIE after exit_mm()'s mmput() so that an oom killed process
is no longer considered for oom kill, but only until exit_mm() has
returned. This was fragile in the past because it relied on
exit_notify() to be reached before no longer considering TIF_MEMDIE
processes.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
They are unnecessary: "zero" can be used in place of "hugetlb_zero" and
passing extra2 == NULL is equivalent to infinity.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kcalloc manages count*sizeof overflow.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the machine doesn't well handle the e820 persistent when hibernate
resuming, then it may cause page fault when writing image to snapshot
buffer:
[ 17.929495] BUG: unable to handle kernel paging request at ffff880069d4f000
[ 17.933469] IP: [<ffffffff810a1cf0>] load_image_lzo+0x810/0xe40
[ 17.933469] PGD 2194067 PUD 77ffff067 PMD 2197067 PTE 0
[ 17.933469] Oops: 0002 [#1] SMP
...
The ffff880069d4f000 page is in e820 reserved region of resume boot
kernel:
[ 0.000000] BIOS-e820: [mem 0x0000000069d4f000-0x0000000069e12fff] reserved
...
[ 0.000000] PM: Registered nosave memory: [mem 0x69d4f000-0x69e12fff]
So snapshot.c mark the pfn to forbidden pages map. But, this
page is also in the memory bitmap in snapshot image because it's an
original page used by image kernel, so it will also mark as an
unsafe(free) page in prepare_image().
That means the page in e820 when resuming mark as "forbidden" and
"free", it causes get_buffer() treat it as an allocated unsafe page.
Then snapshot_write_next() return this page to load_image, load_image
writing content to this address, but this page didn't really allocated
. So, we got page fault.
Although the root cause is from BIOS, I think aggressive check and
significant message in kernel will better then a page fault for
issue tracking, especially when serial console unavailable.
This patch adds code in mark_unsafe_pages() for check does free pages in
nosave region. If so, then it print message and return fault to stop whole
S4 resume process:
[ 8.166004] PM: Image loading progress: 0%
[ 8.658717] PM: 0x6796c000 in e820 nosave region: [mem 0x6796c000-0x6796cfff]
[ 8.918737] PM: Read 2511940 kbytes in 1.04 seconds (2415.32 MB/s)
[ 8.926633] PM: Error -14 resuming
[ 8.933534] PM: Failed to load hibernation image, recovering.
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
[rjw: Subject]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When performing a consuming read, the ring buffer swaps out a
page from the ring buffer with a empty page and this page that
was swapped out becomes the new reader page. The reader page
is owned by the reader and since it was swapped out of the ring
buffer, writers do not have access to it (there's an exception
to that rule, but it's out of scope for this commit).
When reading the "trace" file, it is a non consuming read, which
means that the data in the ring buffer will not be modified.
When the trace file is opened, a ring buffer iterator is allocated
and writes to the ring buffer are disabled, such that the iterator
will not have issues iterating over the data.
Although the ring buffer disabled writes, it does not disable other
reads, or even consuming reads. If a consuming read happens, then
the iterator is reset and starts reading from the beginning again.
My tests would sometimes trigger this bug on my i386 box:
WARNING: CPU: 0 PID: 5175 at kernel/trace/trace.c:1527 __trace_find_cmdline+0x66/0xaa()
Modules linked in:
CPU: 0 PID: 5175 Comm: grep Not tainted 3.16.0-rc3-test+ #8
Hardware name: /DG965MQ, BIOS MQ96510J.86A.0372.2006.0605.1717 06/05/2006
00000000 00000000 f09c9e1c c18796b3 c1b5d74c f09c9e4c c103a0e3 c1b5154b
f09c9e78 00001437 c1b5d74c 000005f7 c10bd85a c10bd85a c1cac57c f09c9eb0
ed0e0000 f09c9e64 c103a185 00000009 f09c9e5c c1b5154b f09c9e78 f09c9e80^M
Call Trace:
[<c18796b3>] dump_stack+0x4b/0x75
[<c103a0e3>] warn_slowpath_common+0x7e/0x95
[<c10bd85a>] ? __trace_find_cmdline+0x66/0xaa
[<c10bd85a>] ? __trace_find_cmdline+0x66/0xaa
[<c103a185>] warn_slowpath_fmt+0x33/0x35
[<c10bd85a>] __trace_find_cmdline+0x66/0xaa^M
[<c10bed04>] trace_find_cmdline+0x40/0x64
[<c10c3c16>] trace_print_context+0x27/0xec
[<c10c4360>] ? trace_seq_printf+0x37/0x5b
[<c10c0b15>] print_trace_line+0x319/0x39b
[<c10ba3fb>] ? ring_buffer_read+0x47/0x50
[<c10c13b1>] s_show+0x192/0x1ab
[<c10bfd9a>] ? s_next+0x5a/0x7c
[<c112e76e>] seq_read+0x267/0x34c
[<c1115a25>] vfs_read+0x8c/0xef
[<c112e507>] ? seq_lseek+0x154/0x154
[<c1115ba2>] SyS_read+0x54/0x7f
[<c188488e>] syscall_call+0x7/0xb
---[ end trace 3f507febd6b4cc83 ]---
>>>> ##### CPU 1 buffer started ####
Which was the __trace_find_cmdline() function complaining about the pid
in the event record being negative.
After adding more test cases, this would trigger more often. Strangely
enough, it would never trigger on a single test, but instead would trigger
only when running all the tests. I believe that was the case because it
required one of the tests to be shutting down via delayed instances while
a new test started up.
After spending several days debugging this, I found that it was caused by
the iterator becoming corrupted. Debugging further, I found out why
the iterator became corrupted. It happened with the rb_iter_reset().
As consuming reads may not read the full reader page, and only part
of it, there's a "read" field to know where the last read took place.
The iterator, must also start at the read position. In the rb_iter_reset()
code, if the reader page was disconnected from the ring buffer, the iterator
would start at the head page within the ring buffer (where writes still
happen). But the mistake there was that it still used the "read" field
to start the iterator on the head page, where it should always start
at zero because readers never read from within the ring buffer where
writes occur.
I originally wrote a patch to have it set the iter->head to 0 instead
of iter->head_page->read, but then I questioned why it wasn't always
setting the iter to point to the reader page, as the reader page is
still valid. The list_empty(reader_page->list) just means that it was
successful in swapping out. But the reader_page may still have data.
There was a bug report a long time ago that was not reproducible that
had something about trace_pipe (consuming read) not matching trace
(iterator read). This may explain why that happened.
Anyway, the correct answer to this bug is to always use the reader page
an not reset the iterator to inside the writable ring buffer.
Cc: stable@vger.kernel.org # 2.6.28+
Fixes: d769041f86 "ring_buffer: implement new locking"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
After writting a test to try to trigger the bug that caused the
ring buffer iterator to become corrupted, I hit another bug:
WARNING: CPU: 1 PID: 5281 at kernel/trace/ring_buffer.c:3766 rb_iter_peek+0x113/0x238()
Modules linked in: ipt_MASQUERADE sunrpc [...]
CPU: 1 PID: 5281 Comm: grep Tainted: G W 3.16.0-rc3-test+ #143
Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS SDBLI944.86P 05/08/2007
0000000000000000 ffffffff81809a80 ffffffff81503fb0 0000000000000000
ffffffff81040ca1 ffff8800796d6010 ffffffff810c138d ffff8800796d6010
ffff880077438c80 ffff8800796d6010 ffff88007abbe600 0000000000000003
Call Trace:
[<ffffffff81503fb0>] ? dump_stack+0x4a/0x75
[<ffffffff81040ca1>] ? warn_slowpath_common+0x7e/0x97
[<ffffffff810c138d>] ? rb_iter_peek+0x113/0x238
[<ffffffff810c138d>] ? rb_iter_peek+0x113/0x238
[<ffffffff810c14df>] ? ring_buffer_iter_peek+0x2d/0x5c
[<ffffffff810c6f73>] ? tracing_iter_reset+0x6e/0x96
[<ffffffff810c74a3>] ? s_start+0xd7/0x17b
[<ffffffff8112b13e>] ? kmem_cache_alloc_trace+0xda/0xea
[<ffffffff8114cf94>] ? seq_read+0x148/0x361
[<ffffffff81132d98>] ? vfs_read+0x93/0xf1
[<ffffffff81132f1b>] ? SyS_read+0x60/0x8e
[<ffffffff8150bf9f>] ? tracesys+0xdd/0xe2
Debugging this bug, which triggers when the rb_iter_peek() loops too
many times (more than 2 times), I discovered there's a case that can
cause that function to legitimately loop 3 times!
rb_iter_peek() is different than rb_buffer_peek() as the rb_buffer_peek()
only deals with the reader page (it's for consuming reads). The
rb_iter_peek() is for traversing the buffer without consuming it, and as
such, it can loop for one more reason. That is, if we hit the end of
the reader page or any page, it will go to the next page and try again.
That is, we have this:
1. iter->head > iter->head_page->page->commit
(rb_inc_iter() which moves the iter to the next page)
try again
2. event = rb_iter_head_event()
event->type_len == RINGBUF_TYPE_TIME_EXTEND
rb_advance_iter()
try again
3. read the event.
But we never get to 3, because the count is greater than 2 and we
cause the WARNING and return NULL.
Up the counter to 3.
Cc: stable@vger.kernel.org # 2.6.37+
Fixes: 69d1b839f7 "ring-buffer: Bind time extend and data events together"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The menu governer makes separate lookups of the CPU runqueue to get
load and number of IO waiters but it can be done with a single lookup.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull networking updates from David Miller:
"Highlights:
1) Steady transitioning of the BPF instructure to a generic spot so
all kernel subsystems can make use of it, from Alexei Starovoitov.
2) SFC driver supports busy polling, from Alexandre Rames.
3) Take advantage of hash table in UDP multicast delivery, from David
Held.
4) Lighten locking, in particular by getting rid of the LRU lists, in
inet frag handling. From Florian Westphal.
5) Add support for various RFC6458 control messages in SCTP, from
Geir Ola Vaagland.
6) Allow to filter bridge forwarding database dumps by device, from
Jamal Hadi Salim.
7) virtio-net also now supports busy polling, from Jason Wang.
8) Some low level optimization tweaks in pktgen from Jesper Dangaard
Brouer.
9) Add support for ipv6 address generation modes, so that userland
can have some input into the process. From Jiri Pirko.
10) Consolidate common TCP connection request code in ipv4 and ipv6,
from Octavian Purdila.
11) New ARP packet logger in netfilter, from Pablo Neira Ayuso.
12) Generic resizable RCU hash table, with intial users in netlink and
nftables. From Thomas Graf.
13) Maintain a name assignment type so that userspace can see where a
network device name came from (enumerated by kernel, assigned
explicitly by userspace, etc.) From Tom Gundersen.
14) Automatic flow label generation on transmit in ipv6, from Tom
Herbert.
15) New packet timestamping facilities from Willem de Bruijn, meant to
assist in measuring latencies going into/out-of the packet
scheduler, latency from TCP data transmission to ACK, etc"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1536 commits)
cxgb4 : Disable recursive mailbox commands when enabling vi
net: reduce USB network driver config options.
tg3: Modify tg3_tso_bug() to handle multiple TX rings
amd-xgbe: Perform phy connect/disconnect at dev open/stop
amd-xgbe: Use dma_set_mask_and_coherent to set DMA mask
net: sun4i-emac: fix memory leak on bad packet
sctp: fix possible seqlock seadlock in sctp_packet_transmit()
Revert "net: phy: Set the driver when registering an MDIO bus device"
cxgb4vf: Turn off SGE RX/TX Callback Timers and interrupts in PCI shutdown routine
team: Simplify return path of team_newlink
bridge: Update outdated comment on promiscuous mode
net-timestamp: ACK timestamp for bytestreams
net-timestamp: TCP timestamping
net-timestamp: SCHED timestamp on entering packet scheduler
net-timestamp: add key to disambiguate concurrent datagrams
net-timestamp: move timestamp flags out of sk_flags
net-timestamp: extend SCM_TIMESTAMPING ancillary data struct
cxgb4i : Move stray CPL definitions to cxgb4 driver
tcp: reduce spurious retransmits due to transient SACK reneging
qlcnic: Initialize dcbnl_ops before register_netdev
...
Pull security subsystem updates from James Morris:
"In this release:
- PKCS#7 parser for the key management subsystem from David Howells
- appoint Kees Cook as seccomp maintainer
- bugfixes and general maintenance across the subsystem"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (94 commits)
X.509: Need to export x509_request_asymmetric_key()
netlabel: shorter names for the NetLabel catmap funcs/structs
netlabel: fix the catmap walking functions
netlabel: fix the horribly broken catmap functions
netlabel: fix a problem when setting bits below the previously lowest bit
PKCS#7: X.509 certificate issuer and subject are mandatory fields in the ASN.1
tpm: simplify code by using %*phN specifier
tpm: Provide a generic means to override the chip returned timeouts
tpm: missing tpm_chip_put in tpm_get_random()
tpm: Properly clean sysfs entries in error path
tpm: Add missing tpm_do_selftest to ST33 I2C driver
PKCS#7: Use x509_request_asymmetric_key()
Revert "selinux: fix the default socket labeling in sock_graft()"
X.509: x509_request_asymmetric_keys() doesn't need string length arguments
PKCS#7: fix sparse non static symbol warning
KEYS: revert encrypted key change
ima: add support for measuring and appraising firmware
firmware_class: perform new LSM checks
security: introduce kernel_fw_from_file hook
PKCS#7: Missing inclusion of linux/err.h
...
- Pass a ksignal struct to it
- Remove unused regs parameter
- Make it private as it's nowhere outside of kernel/signal.c is used
Signed-off-by: Richard Weinberger <richard@nod.at>
Pull timer and time updates from Thomas Gleixner:
"A rather large update of timers, timekeeping & co
- Core timekeeping code is year-2038 safe now for 32bit machines.
Now we just need to fix all in kernel users and the gazillion of
user space interfaces which rely on timespec/timeval :)
- Better cache layout for the timekeeping internal data structures.
- Proper nanosecond based interfaces for in kernel users.
- Tree wide cleanup of code which wants nanoseconds but does hoops
and loops to convert back and forth from timespecs. Some of it
definitely belongs into the ugly code museum.
- Consolidation of the timekeeping interface zoo.
- A fast NMI safe accessor to clock monotonic for tracing. This is a
long standing request to support correlated user/kernel space
traces. With proper NTP frequency correction it's also suitable
for correlation of traces accross separate machines.
- Checkpoint/restart support for timerfd.
- A few NOHZ[_FULL] improvements in the [hr]timer code.
- Code move from kernel to kernel/time of all time* related code.
- New clocksource/event drivers from the ARM universe. I'm really
impressed that despite an architected timer in the newer chips SoC
manufacturers insist on inventing new and differently broken SoC
specific timers.
[ Ed. "Impressed"? I don't think that word means what you think it means ]
- Another round of code move from arch to drivers. Looks like most
of the legacy mess in ARM regarding timers is sorted out except for
a few obnoxious strongholds.
- The usual updates and fixlets all over the place"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
timekeeping: Fixup typo in update_vsyscall_old definition
clocksource: document some basic timekeeping concepts
timekeeping: Use cached ntp_tick_length when accumulating error
timekeeping: Rework frequency adjustments to work better w/ nohz
timekeeping: Minor fixup for timespec64->timespec assignment
ftrace: Provide trace clocks monotonic
timekeeping: Provide fast and NMI safe access to CLOCK_MONOTONIC
seqcount: Add raw_write_seqcount_latch()
seqcount: Provide raw_read_seqcount()
timekeeping: Use tk_read_base as argument for timekeeping_get_ns()
timekeeping: Create struct tk_read_base and use it in struct timekeeper
timekeeping: Restructure the timekeeper some more
clocksource: Get rid of cycle_last
clocksource: Move cycle_last validation to core code
clocksource: Make delta calculation a function
wireless: ath9k: Get rid of timespec conversions
drm: vmwgfx: Use nsec based interfaces
drm: i915: Use nsec based interfaces
timekeeping: Provide ktime_get_raw()
hangcheck-timer: Use ktime_get_ns()
...
Pull irq updates from Thomas Gleixner:
"Nothing spectacular from the irq department this time:
- overhaul of the crossbar chip driver
- overhaul of the spear shirq chip driver
- support for the atmel-aic chip
- code move from arch to drivers
- the usual tiny fixlets
- two reverts worth to mention which undo the too simple attempt of
supporting wakeup interrupts on shared interrupt lines"
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
Revert "irq: Warn when shared interrupts do not match on NO_SUSPEND"
Revert "PM / sleep / irq: Do not suspend wakeup interrupts"
irq: Warn when shared interrupts do not match on NO_SUSPEND
irqchip: atmel-aic: Define irq fixups for atmel SoCs
irqchip: atmel-aic: Implement RTC irq fixup
irqchip: atmel-aic: Add irq fixup infrastructure
irqchip: atmel-aic: Add atmel AIC/AIC5 drivers
irqchip: atmel-aic: Move binding doc to interrupt-controller directory
genirq: generic chip: Export irq_map_generic_chip function
PM / sleep / irq: Do not suspend wakeup interrupts
irqchip: or1k-pic: Migrate from arch/openrisc/
irqchip: crossbar: Allow for quirky hardware with direct hardwiring of GIC
documentation: dt: omap: crossbar: Add description for interrupt consumer
irqchip: crossbar: Introduce centralized check for crossbar write
irqchip: crossbar: Introduce ti, max-crossbar-sources to identify valid crossbar mapping
irqchip: crossbar: Add kerneldoc for crossbar_domain_unmap callback
irqchip: crossbar: Set cb pointer to null in case of error
irqchip: crossbar: Change the goto naming
irqchip: crossbar: Return proper error value
irqchip: crossbar: Fix kerneldoc warning
...
* pm-sleep:
PM / Hibernate: Touch Soft Lockup Watchdog in rtree_next_node
PM / Hibernate: Remove the old memory-bitmap implementation
PM / Hibernate: Iterate over set bits instead of PFNs in swsusp_free()
PM / Hibernate: Implement position keeping in radix tree
PM / Hibernate: Add memory_rtree_find_bit function
PM / Hibernate: Create a Radix-Tree to store memory bitmap
PM / sleep: fix kernel-doc warnings in drivers/base/power/main.c
* pm-cpuidle:
cpuidle: Remove time measurement in poll state
cpuidle: Remove manual selection of the multiple driver support
cpuidle: ladder governor - use macro instead of hardcoded value
cpuidle: big_little: Fix build error
cpuidle: menu governor - remove unused macro STDDEV_THRESH
cpuidle: fix permission for driver name sysfs node
cpuidle: move idle traces to cpuidle_enter_state()
Here's the big pull request for the staging driver tree for 3.17-rc1.
Lots of things in here, over 2000 patches, but the best part is this:
1480 files changed, 39070 insertions(+), 254659 deletions(-)
Thanks to the great work of Kristina Martšenko, 14 different staging
drivers have been removed from the tree as they were obsolete and no one
was willing to work on cleaning them up. Other than the driver
removals, loads of cleanups are in here (comedi, lustre, etc.) as well
as the usual IIO driver updates and additions.
All of this has been in the linux-next tree for a while.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'staging-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
Pull staging driver updates from Greg KH:
"Here's the big pull request for the staging driver tree for 3.17-rc1.
Lots of things in here, over 2000 patches, but the best part is this:
1480 files changed, 39070 insertions(+), 254659 deletions(-)
Thanks to the great work of Kristina Martšenko, 14 different staging
drivers have been removed from the tree as they were obsolete and no
one was willing to work on cleaning them up. Other than the driver
removals, loads of cleanups are in here (comedi, lustre, etc.) as well
as the usual IIO driver updates and additions.
All of this has been in the linux-next tree for a while"
* tag 'staging-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (2199 commits)
staging: comedi: addi_apci_1564: remove diagnostic interrupt support code
staging: comedi: addi_apci_1564: add subdevice to check diagnostic status
staging: wlan-ng: coding style problem fix
staging: wlan-ng: fixing coding style problems
staging: comedi: ii_pci20kc: request and ioremap memory
staging: lustre: bitwise vs logical typo
staging: dgnc: Remove unneeded dgnc_trace.c and dgnc_trace.h
staging: dgnc: rephrase comment
staging: comedi: ni_tio: remove some dead code
staging: rtl8723au: Fix static symbol sparse warning
staging: rtl8723au: usb_dvobj_init(): Remove unused variable 'pdev_desc'
staging: rtl8723au: Do not duplicate kernel provided USB macros
staging: rtl8723au: Remove never set struct pwrctrl_priv.bHWPowerdown
staging: rtl8723au: Remove two never set variables
staging: rtl8723au: RSSI_test is never set
staging:r8190: coding style: Fixed checkpatch reported Error
staging:r8180: coding style: Fixed too long lines
staging:r8180: coding style: Fixed commenting style
staging: lustre: ptlrpc: lproc_ptlrpc.c - fix dereferenceing user space buffer
staging: lustre: ldlm: ldlm_resource.c - fix dereferenceing user space buffer
...
Pull scheduler updates from Ingo Molnar:
- Move the nohz kick code out of the scheduler tick to a dedicated IPI,
from Frederic Weisbecker.
This necessiated quite some background infrastructure rework,
including:
* Clean up some irq-work internals
* Implement remote irq-work
* Implement nohz kick on top of remote irq-work
* Move full dynticks timer enqueue notification to new kick
* Move multi-task notification to new kick
* Remove unecessary barriers on multi-task notification
- Remove proliferation of wait_on_bit() action functions and allow
wait_on_bit_action() functions to support a timeout. (Neil Brown)
- Another round of sched/numa improvements, cleanups and fixes. (Rik
van Riel)
- Implement fast idling of CPUs when the system is partially loaded,
for better scalability. (Tim Chen)
- Restructure and fix the CPU hotplug handling code that may leave
cfs_rq and rt_rq's throttled when tasks are migrated away from a dead
cpu. (Kirill Tkhai)
- Robustify the sched topology setup code. (Peterz Zijlstra)
- Improve sched_feat() handling wrt. static_keys (Jason Baron)
- Misc fixes.
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
sched/fair: Fix 'make xmldocs' warning caused by missing description
sched: Use macro for magic number of -1 for setparam
sched: Robustify topology setup
sched: Fix sched_setparam() policy == -1 logic
sched: Allow wait_on_bit_action() functions to support a timeout
sched: Remove proliferation of wait_on_bit() action functions
sched/numa: Revert "Use effective_load() to balance NUMA loads"
sched: Fix static_key race with sched_feat()
sched: Remove extra static_key*() function indirection
sched/rt: Fix replenish_dl_entity() comments to match the current upstream code
sched: Transform resched_task() into resched_curr()
sched/deadline: Kill task_struct->pi_top_task
sched: Rework check_for_tasks()
sched/rt: Enqueue just unthrottled rt_rq back on the stack in __disable_runtime()
sched/fair: Disable runtime_enabled on dying rq
sched/numa: Change scan period code to match intent
sched/numa: Rework best node setting in task_numa_migrate()
sched/numa: Examine a task move when examining a task swap
sched/numa: Simplify task_numa_compare()
sched/numa: Use effective_load() to balance NUMA loads
...
Pull perf changes from Ingo Molnar:
"Kernel side changes:
- Consolidate the PMU interrupt-disabled code amongst architectures
(Vince Weaver)
- misc fixes
Tooling changes (new features, user visible changes):
- Add support for pagefault tracing in 'trace', please see multiple
examples in the changeset messages (Stanislav Fomichev).
- Add pagefault statistics in 'trace' (Stanislav Fomichev)
- Add header for columns in 'top' and 'report' TUI browsers (Jiri
Olsa)
- Add pagefault statistics in 'trace' (Stanislav Fomichev)
- Add IO mode into timechart command (Stanislav Fomichev)
- Fallback to syscalls:* when raw_syscalls:* is not available in the
perl and python perf scripts. (Daniel Bristot de Oliveira)
- Add --repeat global option to 'perf bench' to be used in benchmarks
such as the existing 'futex' one, that was modified to use it
instead of a local option. (Davidlohr Bueso)
- Fix fd -> pathname resolution in 'trace', be it using /proc or a
vfs_getname probe point. (Arnaldo Carvalho de Melo)
- Add suggestion of how to set perf_event_paranoid sysctl, to help
non-root users trying tools like 'trace' to get a working
environment. (Arnaldo Carvalho de Melo)
- Updates from trace-cmd for traceevent plugin_kvm plus args cleanup
(Steven Rostedt, Jan Kiszka)
- Support S/390 in 'perf kvm stat' (Alexander Yarygin)
Tooling infrastructure changes:
- Allow reserving a row for header purposes in the hists browser
(Arnaldo Carvalho de Melo)
- Various fixes and prep work related to supporting Intel PT (Adrian
Hunter)
- Introduce multiple debug variables control (Jiri Olsa)
- Add callchain and additional sample information for python scripts
(Joseph Schuchart)
- More prep work to support Intel PT: (Adrian Hunter)
- Polishing 'script' BTS output
- 'inject' can specify --kallsym
- VDSO is per machine, not a global var
- Expose data addr lookup functions previously private to 'script'
- Large mmap fixes in events processing
- Include standard stringify macros in power pc code (Sukadev
Bhattiprolu)
Tooling cleanups:
- Convert open coded equivalents to asprintf() (Andy Shevchenko)
- Remove needless reassignments in 'trace' (Arnaldo Carvalho de Melo)
- Cache the is_exit syscall test in 'trace) (Arnaldo Carvalho de
Melo)
- No need to reimplement err() in 'perf bench sched-messaging', drop
barf(). (Davidlohr Bueso).
- Remove ev_name argument from perf_evsel__hists_browse, can be
obtained from the other parameters. (Jiri Olsa)
Tooling fixes:
- Fix memory leak in the 'sched-messaging' perf bench test.
(Davidlohr Bueso)
- The -o and -n 'perf bench mem' options are mutually exclusive, emit
error when both are specified. (Davidlohr Bueso)
- Fix scrollbar refresh row index in the ui browser, problem exposed
now that headers will be added and will be allowed to be switched
on/off. (Jiri Olsa)
- Handle the num array type in python properly (Sebastian Andrzej
Siewior)
- Fix wrong condition for allocation failure (Jiri Olsa)
- Adjust callchain based on DWARF debug info on powerpc (Sukadev
Bhattiprolu)
- Fix a risk for doing free on uninitialized pointer in traceevent
lib (Rickard Strandqvist)
- Update attr test with PERF_FLAG_FD_CLOEXEC flag (Jiri Olsa)
- Enable close-on-exec flag on perf file descriptor (Yann Droneaud)
- Fix build on gcc 4.4.7 (Arnaldo Carvalho de Melo)
- Event ordering fixes (Jiri Olsa)"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (123 commits)
Revert "perf tools: Fix jump label always changing during tracing"
perf tools: Fix perf usage string leftover
perf: Check permission only for parent tracepoint event
perf record: Store PERF_RECORD_FINISHED_ROUND only for nonempty rounds
perf record: Always force PERF_RECORD_FINISHED_ROUND event
perf inject: Add --kallsyms parameter
perf tools: Expose 'addr' functions so they can be reused
perf session: Fix accounting of ordered samples queue
perf powerpc: Include util/util.h and remove stringify macros
perf tools: Fix build on gcc 4.4.7
perf tools: Add thread parameter to vdso__dso_findnew()
perf tools: Add dso__type()
perf tools: Separate the VDSO map name from the VDSO dso name
perf tools: Add vdso__new()
perf machine: Fix the lifetime of the VDSO temporary file
perf tools: Group VDSO global variables into a structure
perf session: Add ability to skip 4GiB or more
perf session: Add ability to 'skip' a non-piped event stream
perf tools: Pass machine to vdso__dso_findnew()
perf tools: Add dso__data_size()
...
Pull locking updates from Ingo Molnar:
"The main changes in this cycle are:
- big rtmutex and futex cleanup and robustification from Thomas
Gleixner
- mutex optimizations and refinements from Jason Low
- arch_mutex_cpu_relax() removal and related cleanups
- smaller lockdep tweaks"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
arch, locking: Ciao arch_mutex_cpu_relax()
locking/lockdep: Only ask for /proc/lock_stat output when available
locking/mutexes: Optimize mutex trylock slowpath
locking/mutexes: Try to acquire mutex only if it is unlocked
locking/mutexes: Delete the MUTEX_SHOW_NO_WAITER macro
locking/mutexes: Correct documentation on mutex optimistic spinning
rtmutex: Make the rtmutex tester depend on BROKEN
futex: Simplify futex_lock_pi_atomic() and make it more robust
futex: Split out the first waiter attachment from lookup_pi_state()
futex: Split out the waiter check from lookup_pi_state()
futex: Use futex_top_waiter() in lookup_pi_state()
futex: Make unlock_pi more robust
rtmutex: Avoid pointless requeueing in the deadlock detection chain walk
rtmutex: Cleanup deadlock detector debug logic
rtmutex: Confine deadlock logic to futex
rtmutex: Simplify remove_waiter()
rtmutex: Document pi chain walk
rtmutex: Clarify the boost/deboost part
rtmutex: No need to keep task ref for lock owner check
rtmutex: Simplify and document try_to_take_rtmutex()
...
Pull RCU changes from Ingo Molar:
"The main changes:
- torture-test updates
- callback-offloading changes
- maintainership changes
- update RCU documentation
- miscellaneous fixes"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
rcu: Allow for NULL tick_nohz_full_mask when nohz_full= missing
rcu: Fix a sparse warning in rcu_report_unblock_qs_rnp()
rcu: Fix a sparse warning in rcu_initiate_boost()
rcu: Fix __rcu_reclaim() to use true/false for bool
rcu: Remove CONFIG_PROVE_RCU_DELAY
rcu: Use __this_cpu_read() instead of per_cpu_ptr()
rcu: Don't use NMIs to dump other CPUs' stacks
rcu: Bind grace-period kthreads to non-NO_HZ_FULL CPUs
rcu: Simplify priority boosting by putting rt_mutex in rcu_node
rcu: Check both root and current rcu_node when setting up future grace period
rcu: Allow post-unlock reference for rt_mutex
rcu: Loosen __call_rcu()'s rcu_head alignment constraint
rcu: Eliminate read-modify-write ACCESS_ONCE() calls
rcu: Remove redundant ACCESS_ONCE() from tick_do_timer_cpu
rcu: Make rcu node arrays static const char * const
signal: Explain local_irq_save() call
rcu: Handle obsolete references to TINY_PREEMPT_RCU
rcu: Document deadlock-avoidance information for rcu_read_unlock()
scripts: Teach get_maintainer.pl about the new "R:" tag
rcu: Update rcu torture maintainership filename patterns
...
As he found some small bugs that went into 3.16, and these changes were
based on that, I had to apply his changes to a separate branch than
my main development branch.
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Merge tag 'trace-3.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing filter cleanups from Steven Rostedt:
"Oleg Nesterov did several clean ups with the tracing filter code. As
he found some small bugs that went into 3.16, and these changes were
based on that, I had to apply his changes to a separate branch than my
main development branch.
This was based on work that was already pulled into 3.16, and is a
separate pull request to keep from having local merges in my pull
request"
* tag 'trace-3.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Kill "filter_string" arg of replace_preds()
tracing: Change apply_subsystem_event_filter() paths to check file->system == dir
tracing: Kill ftrace_event_call->files
tracing/uprobes: Kill the dead TRACE_EVENT_FL_USE_CALL_FILTER logic
tracing: Kill call_filter_disable()
tracing: Kill destroy_call_preds()
tracing: Kill destroy_preds() and destroy_file_preds()
to the ftrace function callback infrastructure. It's introducing a
way to allow different functions to call directly different trampolines
instead of all calling the same "mcount" one.
The only user of this for now is the function graph tracer, which always
had a different trampoline, but the function tracer trampoline was called
and did basically nothing, and then the function graph tracer trampoline
was called. The difference now, is that the function graph tracer
trampoline can be called directly if a function is only being traced by
the function graph trampoline. If function tracing is also happening on
the same function, the old way is still done.
The accounting for this takes up more memory when function graph tracing
is activated, as it needs to keep track of which functions it uses.
I have a new way that wont take as much memory, but it's not ready yet
for this merge window, and will have to wait for the next one.
Another big change was the removal of the ftrace_start/stop() calls that
were used by the suspend/resume code that stopped function tracing when
entering into suspend and resume paths. The stop of ftrace was done
because there was some function that would crash the system if one called
smp_processor_id()! The stop/start was a big hammer to solve the issue
at the time, which was when ftrace was first introduced into Linux.
Now ftrace has better infrastructure to debug such issues, and I found
the problem function and labeled it with "notrace" and function tracing
can now safely be activated all the way down into the guts of suspend
and resume.
Other changes include clean ups of uprobe code.
Clean up of the trace_seq() code.
And other various small fixes and clean ups to ftrace and tracing.
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Merge tag 'trace-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"This pull request has a lot of work done. The main thing is the
changes to the ftrace function callback infrastructure. It's
introducing a way to allow different functions to call directly
different trampolines instead of all calling the same "mcount" one.
The only user of this for now is the function graph tracer, which
always had a different trampoline, but the function tracer trampoline
was called and did basically nothing, and then the function graph
tracer trampoline was called. The difference now, is that the
function graph tracer trampoline can be called directly if a function
is only being traced by the function graph trampoline. If function
tracing is also happening on the same function, the old way is still
done.
The accounting for this takes up more memory when function graph
tracing is activated, as it needs to keep track of which functions it
uses. I have a new way that wont take as much memory, but it's not
ready yet for this merge window, and will have to wait for the next
one.
Another big change was the removal of the ftrace_start/stop() calls
that were used by the suspend/resume code that stopped function
tracing when entering into suspend and resume paths. The stop of
ftrace was done because there was some function that would crash the
system if one called smp_processor_id()! The stop/start was a big
hammer to solve the issue at the time, which was when ftrace was first
introduced into Linux. Now ftrace has better infrastructure to debug
such issues, and I found the problem function and labeled it with
"notrace" and function tracing can now safely be activated all the way
down into the guts of suspend and resume
Other changes include clean ups of uprobe code, clean up of the
trace_seq() code, and other various small fixes and clean ups to
ftrace and tracing"
* tag 'trace-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (57 commits)
ftrace: Add warning if tramp hash does not match nr_trampolines
ftrace: Fix trampoline hash update check on rec->flags
ring-buffer: Use rb_page_size() instead of open coded head_page size
ftrace: Rename ftrace_ops field from trampolines to nr_trampolines
tracing: Convert local function_graph functions to static
ftrace: Do not copy old hash when resetting
tracing: let user specify tracing_thresh after selecting function_graph
ring-buffer: Always run per-cpu ring buffer resize with schedule_work_on()
tracing: Remove function_trace_stop and HAVE_FUNCTION_TRACE_MCOUNT_TEST
s390/ftrace: remove check of obsolete variable function_trace_stop
arm64, ftrace: Remove check of obsolete variable function_trace_stop
Blackfin: ftrace: Remove check of obsolete variable function_trace_stop
metag: ftrace: Remove check of obsolete variable function_trace_stop
microblaze: ftrace: Remove check of obsolete variable function_trace_stop
MIPS: ftrace: Remove check of obsolete variable function_trace_stop
parisc: ftrace: Remove check of obsolete variable function_trace_stop
sh: ftrace: Remove check of obsolete variable function_trace_stop
sparc64,ftrace: Remove check of obsolete variable function_trace_stop
tile: ftrace: Remove check of obsolete variable function_trace_stop
ftrace: x86: Remove check of obsolete variable function_trace_stop
...
Pull cgroup changes from Tejun Heo:
"Mostly changes to get the v2 interface ready. The core features are
mostly ready now and I think it's reasonable to expect to drop the
devel mask in one or two devel cycles at least for a subset of
controllers.
- cgroup added a controller dependency mechanism so that block cgroup
can depend on memory cgroup. This will be used to finally support
IO provisioning on the writeback traffic, which is currently being
implemented.
- The v2 interface now uses a separate table so that the interface
files for the new interface are explicitly declared in one place.
Each controller will explicitly review and add the files for the
new interface.
- cpuset is getting ready for the hierarchical behavior which is in
the similar style with other controllers so that an ancestor's
configuration change doesn't change the descendants' configurations
irreversibly and processes aren't silently migrated when a CPU or
node goes down.
All the changes are to the new interface and no behavior changed for
the multiple hierarchies"
* 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (29 commits)
cpuset: fix the WARN_ON() in update_nodemasks_hier()
cgroup: initialize cgrp_dfl_root_inhibit_ss_mask from !->dfl_files test
cgroup: make CFTYPE_ONLY_ON_DFL and CFTYPE_NO_ internal to cgroup core
cgroup: distinguish the default and legacy hierarchies when handling cftypes
cgroup: replace cgroup_add_cftypes() with cgroup_add_legacy_cftypes()
cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes
cgroup: split cgroup_base_files[] into cgroup_{dfl|legacy}_base_files[]
cpuset: export effective masks to userspace
cpuset: allow writing offlined masks to cpuset.cpus/mems
cpuset: enable onlined cpu/node in effective masks
cpuset: refactor cpuset_hotplug_update_tasks()
cpuset: make cs->{cpus, mems}_allowed as user-configured masks
cpuset: apply cs->effective_{cpus,mems}
cpuset: initialize top_cpuset's configured masks at mount
cpuset: use effective cpumask to build sched domains
cpuset: inherit ancestor's masks if effective_{cpus, mems} becomes empty
cpuset: update cs->effective_{cpus, mems} when config changes
cpuset: update cpuset->effective_{cpus,mems} at hotplug
cpuset: add cs->effective_cpus and cs->effective_mems
cgroup: clean up sane_behavior handling
...
Pull percpu updates from Tejun Heo:
- Major reorganization of percpu header files which I think makes
things a lot more readable and logical than before.
- percpu-refcount is updated so that it requires explicit destruction
and can be reinitialized if necessary. This was pulled into the
block tree to replace the custom percpu refcnting implemented in
blk-mq.
- In the process, percpu and percpu-refcount got cleaned up a bit
* 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (21 commits)
percpu-refcount: implement percpu_ref_reinit() and percpu_ref_is_zero()
percpu-refcount: require percpu_ref to be exited explicitly
percpu-refcount: use unsigned long for pcpu_count pointer
percpu-refcount: add helpers for ->percpu_count accesses
percpu-refcount: one bit is enough for REF_STATUS
percpu-refcount, aio: use percpu_ref_cancel_init() in ioctx_alloc()
workqueue: stronger test in process_one_work()
workqueue: clear POOL_DISASSOCIATED in rebind_workers()
percpu: Use ALIGN macro instead of hand coding alignment calculation
percpu: invoke __verify_pcpu_ptr() from the generic part of accessors and operations
percpu: preffity percpu header files
percpu: use raw_cpu_*() to define __this_cpu_*()
percpu: reorder macros in percpu header files
percpu: move {raw|this}_cpu_*() definitions to include/linux/percpu-defs.h
percpu: move generic {raw|this}_cpu_*_N() definitions to include/asm-generic/percpu.h
percpu: only allow sized arch overrides for {raw|this}_cpu_*() ops
percpu: reorganize include/linux/percpu-defs.h
percpu: move accessors from include/linux/percpu.h to percpu-defs.h
percpu: include/asm-generic/percpu.h should contain only arch-overridable parts
percpu: introduce arch_raw_cpu_ptr()
...
Pull workqueue updates from Tejun Heo:
"Lai has been doing a lot of cleanups of workqueue and kthread_work.
No significant behavior change. Just a lot of cleanups all over the
place. Some are a bit invasive but overall nothing too dangerous"
* 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
kthread_work: remove the unused wait_queue_head
kthread_work: wake up worker only when the worker is idle
workqueue: use nr_node_ids instead of wq_numa_tbl_len
workqueue: remove the misnamed out_unlock label in get_unbound_pool()
workqueue: remove the stale comment in pwq_unbound_release_workfn()
workqueue: move rescuer pool detachment to the end
workqueue: unfold start_worker() into create_worker()
workqueue: remove @wakeup from worker_set_flags()
workqueue: remove an unneeded UNBOUND test before waking up the next worker
workqueue: wake regular worker if need_more_worker() when rescuer leave the pool
workqueue: alloc struct worker on its local node
workqueue: reuse the already calculated pwq in try_to_grab_pending()
workqueue: stronger test in process_one_work()
workqueue: clear POOL_DISASSOCIATED in rebind_workers()
workqueue: sanity check pool->cpu in wq_worker_sleeping()
workqueue: clear leftover flags when detached
workqueue: remove useless WARN_ON_ONCE()
workqueue: use schedule_timeout_interruptible() instead of open code
workqueue: remove the empty check in too_many_workers()
workqueue: use "pool->cpu < 0" to stand for an unbound pool
Pull crypto update from Herbert Xu:
- CTR(AES) optimisation on x86_64 using "by8" AVX.
- arm64 support to ccp
- Intel QAT crypto driver
- Qualcomm crypto engine driver
- x86-64 assembly optimisation for 3DES
- CTR(3DES) speed test
- move FIPS panic from module.c so that it only triggers on crypto
modules
- SP800-90A Deterministic Random Bit Generator (drbg).
- more test vectors for ghash.
- tweak self tests to catch partial block bugs.
- misc fixes.
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (94 commits)
crypto: drbg - fix failure of generating multiple of 2**16 bytes
crypto: ccp - Do not sign extend input data to CCP
crypto: testmgr - add missing spaces to drbg error strings
crypto: atmel-tdes - Switch to managed version of kzalloc
crypto: atmel-sha - Switch to managed version of kzalloc
crypto: testmgr - use chunks smaller than algo block size in chunk tests
crypto: qat - Fixed SKU1 dev issue
crypto: qat - Use hweight for bit counting
crypto: qat - Updated print outputs
crypto: qat - change ae_num to ae_id
crypto: qat - change slice->regions to slice->region
crypto: qat - use min_t macro
crypto: qat - remove unnecessary parentheses
crypto: qat - remove unneeded header
crypto: qat - checkpatch blank lines
crypto: qat - remove unnecessary return codes
crypto: Resolve shadow warnings
crypto: ccp - Remove "select OF" from Kconfig
crypto: caam - fix DECO RSR polling
crypto: qce - Let 'DEV_QCE' depend on both HAS_DMA and HAS_IOMEM
...
Pull timer fixes from Thomas Gleixner:
"Two fixes in the timer area:
- a long-standing lock inversion due to a printk
- suspend-related hrtimer corruption in sched_clock"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timer: Fix lock inversion between hrtimer_bases.lock and scheduler locks
sched_clock: Avoid corrupting hrtimer tree during suspend
clean up names related to socket filtering and bpf in the following way:
- everything that deals with sockets keeps 'sk_*' prefix
- everything that is pure BPF is changed to 'bpf_*' prefix
split 'struct sk_filter' into
struct sk_filter {
atomic_t refcnt;
struct rcu_head rcu;
struct bpf_prog *prog;
};
and
struct bpf_prog {
u32 jited:1,
len:31;
struct sock_fprog_kern *orig_prog;
unsigned int (*bpf_func)(const struct sk_buff *skb,
const struct bpf_insn *filter);
union {
struct sock_filter insns[0];
struct bpf_insn insnsi[0];
struct work_struct work;
};
};
so that 'struct bpf_prog' can be used independent of sockets and cleans up
'unattached' bpf use cases
split SK_RUN_FILTER macro into:
SK_RUN_FILTER to be used with 'struct sk_filter *' and
BPF_PROG_RUN to be used with 'struct bpf_prog *'
__sk_filter_release(struct sk_filter *) gains
__bpf_prog_release(struct bpf_prog *) helper function
also perform related renames for the functions that work
with 'struct bpf_prog *', since they're on the same lines:
sk_filter_size -> bpf_prog_size
sk_filter_select_runtime -> bpf_prog_select_runtime
sk_filter_free -> bpf_prog_free
sk_unattached_filter_create -> bpf_prog_create
sk_unattached_filter_destroy -> bpf_prog_destroy
sk_store_orig_filter -> bpf_prog_store_orig_filter
sk_release_orig_filter -> bpf_release_orig_filter
__sk_migrate_filter -> bpf_migrate_filter
__sk_prepare_filter -> bpf_prepare_filter
API for attaching classic BPF to a socket stays the same:
sk_attach_filter(prog, struct sock *)/sk_detach_filter(struct sock *)
and SK_RUN_FILTER(struct sk_filter *, ctx) to execute a program
which is used by sockets, tun, af_packet
API for 'unattached' BPF programs becomes:
bpf_prog_create(struct bpf_prog **)/bpf_prog_destroy(struct bpf_prog *)
and BPF_PROG_RUN(struct bpf_prog *, ctx) to execute a program
which is used by isdn, ppp, team, seccomp, ptp, xt_bpf, cls_bpf, test_bpf
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
to indicate that this function is converting classic BPF into eBPF
and not related to sockets
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
trivial rename to indicate that this functions performs classic BPF checking
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit 4fae4e7624.
Undo because it breaks working systems.
Requested-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This reverts commit d709f7bcbb.
Undo, because it might break exisiting functionality.
Requested-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
free_huge_page() is undefined without CONFIG_HUGETLBFS and there's no
need to filter PageHuge() page is such a configuration either, so avoid
exporting the symbol to fix a build error:
In file included from kernel/kexec.c:14:0:
kernel/kexec.c: In function 'crash_save_vmcoreinfo_init':
kernel/kexec.c:1623:20: error: 'free_huge_page' undeclared (first use in this function)
VMCOREINFO_SYMBOL(free_huge_page);
^
Introduced by commit 8f1d26d0e5 ("kexec: export free_huge_page to
VMCOREINFO")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Acked-by: Olof Johansson <olof@lixom.net>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
My IBM email addresses haven't worked for years; also map some
old-but-functional forwarding addresses to my canonical address.
Update my GPG key fingerprint; I moved to 4096R a long time ago.
Update description.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
PG_head_mask was added into VMCOREINFO to filter huge pages in b3acc56bfe
("kexec: save PG_head_mask in VMCOREINFO"), but makedumpfile still need
another symbol to filter *hugetlbfs* pages.
If a user hope to filter user pages, makedumpfile tries to exclude them by
checking the condition whether the page is anonymous, but hugetlbfs pages
aren't anonymous while they also be user pages.
We know it's possible to detect them in the same way as PageHuge(),
so we need the start address of free_huge_page():
int PageHuge(struct page *page)
{
if (!PageCompound(page))
return 0;
page = compound_head(page);
return get_compound_page_dtor(page) == free_huge_page;
}
For that reason, this patch changes free_huge_page() into public
to export it to VMCOREINFO.
Signed-off-by: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The WARN_ON() is used to check if we break the legal hierarchy, on
which the effective mems should be equal to configured mems.
Reported-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
Tested-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
The synchronous syncrhonize_rcu in switch_task_namespaces makes setns
a sufficiently expensive system call that people have complained.
Upon inspect nsproxy no longer needs rcu protection for remote reads.
remote reads are rare. So optimize for same process reads and write
by switching using rask_lock instead.
This yields a simpler to understand lock, and a faster setns system call.
In particular this fixes a performance regression observed
by Rafael David Tinoco <rafael.tinoco@canonical.com>.
This is effectively a revert of Pavel Emelyanov's commit
cf7b708c8d Make access to task's nsproxy lighter
from 2007. The race this originialy fixed no longer exists as
do_notify_parent uses task_active_pid_ns(parent) instead of
parent->nsproxy.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
When a memory bitmap is fully populated on a large memory
machine (several TB of RAM) it can take more than a minute
to walk through all bits. This causes the soft lockup
detector on these machine to report warnings.
Avoid this by touching the soft lockup watchdog in the
memory bitmap walking code.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The radix tree implementatio is proved to work the same as
the old implementation now. So the old implementation can be
removed to finish the switch to the radix tree for the
memory bitmaps.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The existing implementation of swsusp_free iterates over all
pfns in the system and checks every bit in the two memory
bitmaps.
This doesn't scale very well with large numbers of pfns,
especially when the bitmaps are not populated very densly.
Change the algorithm to iterate over the set bits in the
bitmaps instead to make it scale better in large memory
configurations.
Also add a memory_bm_clear_current() helper function that
clears the bit for the last position returned from the
memory bitmap.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add code to remember the last position that was requested in
the radix tree. Use it as a cache for faster linear walking
of the bitmap in the memory_bm_rtree_next_pfn() function
which is also added with this patch.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add a function to find a bit in the radix tree for a given
pfn. Also add code to the memory bitmap wrapper functions to
use the radix tree together with the existing memory bitmap
implementation.
On read accesses compare the results of both bitmaps to make
sure the radix tree behaves the same way.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch adds the code to allocate and build the radix
tree to store the memory bitmap. The old data structure is
left in place until the radix tree implementation is
finished.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If the worker is already executing a work item when another is queued,
we can safely skip wakeup without worrying about stalling queue thus
avoiding waking up the busy worker spuriously. Spurious wakeups
should be fine but still isn't nice and avoiding it is trivial here.
tj: Updated description.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch fix following warning caused by missing description
"overload" in kernel/sched/fair.c
Warning(.//kernel/sched/fair.c:5906): No description found for
parameter 'overload'
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1406518686-7274-1-git-send-email-standby24x7@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Instead of passing around a magic number -1 for the sched_setparam()
policy, use a more descriptive macro name like SETPARAM_POLICY.
[ based on top of Daniel's sched_setparam() fix ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Daniel Bristot de Oliveira<bristot@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140723112826.6ed6cbce@gandalf.local.home
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We hard assume that higher topology levels are supersets of lower
levels.
Detect, warn and try to fixup when we encounter this violated.
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Bruno Wolff III <bruno@wolff.to>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140722094740.GJ12054@laptop.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There's no need to check cloned event's permission once the
parent was already checked.
Also the code is checking 'current' process permissions, which
is not owner process for cloned events, thus could end up with
wrong permission check result.
Reported-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Tested-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1405079782-8139-1-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'v3.16-rc7' into perf/core, to merge in the latest fixes before applying new changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The scheduler uses policy == -1 to preserve the current policy state to
implement sched_setparam(). But, as (int) -1 is equals to 0xffffffff,
it's matching the if (policy & SCHED_RESET_ON_FORK) on
_sched_setscheduler(). This match changes the policy value to an
invalid value, breaking the sched_setparam() syscall.
This patch checks policy == -1 before check the SCHED_RESET_ON_FORK flag.
The following program shows the bug:
int main(void)
{
struct sched_param param = {
.sched_priority = 5,
};
sched_setscheduler(0, SCHED_FIFO, ¶m);
param.sched_priority = 1;
sched_setparam(0, ¶m);
param.sched_priority = 0;
sched_getparam(0, ¶m);
if (param.sched_priority != 1)
printf("failed priority setting (found %d instead of 1)\n",
param.sched_priority);
else
printf("priority setting fine\n");
}
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org> # 3.14+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Fixes: 7479f3c9cf "sched: Move SCHED_RESET_ON_FORK into attr::sched_flags"
Link: http://lkml.kernel.org/r/9ebe0566a08dbbb3999759d3f20d6004bb2dbcfa.1406079891.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
* acpi-pm:
ACPI / PM: Use ACPI_COMPANION() instead of ACPI_HANDLE()
ACPI / PM: Always enable wakeup GPEs when enabling device wakeup
ACPI / PM: Revork the handling of ACPI device wakeup notifications
PM: Create PM workqueue if runtime PM is not configured too
* acpi-sleep:
ACPI / sleep: Do not save NVS for new machines to accelerate S3
* acpi-button:
ACPI / button: Do not propagate wakeup-from-suspend events
Pull perf fixes from Thomas Gleixner:
"A bunch of fixes for perf and kprobes:
- revert a commit that caused a perf group regression
- silence dmesg spam
- fix kprobe probing errors on ia64 and ppc64
- filter kprobe faults from userspace
- lockdep fix for perf exit path
- prevent perf #GP in KVM guest
- correct perf event and filters"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
kprobes: Fix "Failed to find blacklist" probing errors on ia64 and ppc64
kprobes/x86: Don't try to resolve kprobe faults from userspace
perf/x86/intel: Avoid spamming kernel log for BTS buffer failure
perf/x86/intel: Protect LBR and extra_regs against KVM lying
perf: Fix lockdep warning on process exit
perf/x86/intel/uncore: Fix SNB-EP/IVT Cbox filter mappings
perf/x86/intel: Use proper dTLB-load-misses event on IvyBridge
perf: Revert ("perf: Always destroy groups on exit")
Symbols starting with .L are ELF local symbols and should not appear
in ELF symbol tables. However, unfortunately ARM binutils leaks the
.LANCHOR symbols into the symbol table, which leads kallsyms to report
these symbols rather than the real name. It is not very useful when
%pf reports symbols against these leaked .LANCHOR symbols.
Arrange for kallsyms to ignore these symbols using the same mechanism
that is used for the ARM mapping symbols.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
It is just a small optimization that allows to replace few
occurrences of within_module_init() || within_module_core()
with a single call.
Signed-off-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
eBPF is used by socket filtering, seccomp and soon by tracing and
exposed to userspace, therefore 'sock_filter_int' name is not accurate.
Rename it to 'bpf_insn'
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When suspend_device_irqs() iterates all descriptors, its pointless if
one has NO_SUSPEND set while another has not.
Validate on request_irq() that NO_SUSPEND state maches for SHARED
interrupts.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Link: http://lkml.kernel.org/r/20140724133921.GY6758@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
After adding all the records to the tramp_hash, add a check that makes
sure that the number of records added matches the number of records
expected to match and do a WARN_ON and disable ftrace if they do
not match.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In the loop of ftrace_save_ops_tramp_hash(), it adds all the recs
to the ops hash if the rec has only one callback attached and the
ops is connected to the rec. It gives a nasty warning and shuts down
ftrace if the rec doesn't have a trampoline set for it. But this
can happen with the following scenario:
# cd /sys/kernel/debug/tracing
# echo schedule do_IRQ > set_ftrace_filter
# mkdir instances/foo
# echo schedule > instances/foo/set_ftrace_filter
# echo function_graph > current_function
# echo function > instances/foo/current_function
# echo nop > instances/foo/current_function
The above would then trigger the following warning and disable
ftrace:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 3145 at kernel/trace/ftrace.c:2212 ftrace_run_update_code+0xe4/0x15b()
Modules linked in: ipt_MASQUERADE sunrpc ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ip [...]
CPU: 1 PID: 3145 Comm: bash Not tainted 3.16.0-rc3-test+ #136
Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS SDBLI944.86P 05/08/2007
0000000000000000 ffffffff81808a88 ffffffff81502130 0000000000000000
ffffffff81040ca1 ffff880077c08000 ffffffff810bd286 0000000000000001
ffffffff81a56830 ffff88007a041be0 ffff88007a872d60 00000000000001be
Call Trace:
[<ffffffff81502130>] ? dump_stack+0x4a/0x75
[<ffffffff81040ca1>] ? warn_slowpath_common+0x7e/0x97
[<ffffffff810bd286>] ? ftrace_run_update_code+0xe4/0x15b
[<ffffffff810bd286>] ? ftrace_run_update_code+0xe4/0x15b
[<ffffffff810bda1a>] ? ftrace_shutdown+0x11c/0x16b
[<ffffffff810bda87>] ? unregister_ftrace_function+0x1e/0x38
[<ffffffff810cc7e1>] ? function_trace_reset+0x1a/0x28
[<ffffffff810c924f>] ? tracing_set_tracer+0xc1/0x276
[<ffffffff810c9477>] ? tracing_set_trace_write+0x73/0x91
[<ffffffff81132383>] ? __sb_start_write+0x9a/0xcc
[<ffffffff8120478f>] ? security_file_permission+0x1b/0x31
[<ffffffff81130e49>] ? vfs_write+0xac/0x11c
[<ffffffff8113115d>] ? SyS_write+0x60/0x8e
[<ffffffff81508112>] ? system_call_fastpath+0x16/0x1b
---[ end trace 938c4415cbc7dc96 ]---
------------[ cut here ]------------
Link: http://lkml.kernel.org/r/20140723120805.GB21376@redhat.com
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This is effectively a revert of 7b9a7ec565
plus fixing it a different way...
We found, when trying to run an application from an application which
had dropped privs that the kernel does security checks on undefined
capability bits. This was ESPECIALLY difficult to debug as those
undefined bits are hidden from /proc/$PID/status.
Consider a root application which drops all capabilities from ALL 4
capability sets. We assume, since the application is going to set
eff/perm/inh from an array that it will clear not only the defined caps
less than CAP_LAST_CAP, but also the higher 28ish bits which are
undefined future capabilities.
The BSET gets cleared differently. Instead it is cleared one bit at a
time. The problem here is that in security/commoncap.c::cap_task_prctl()
we actually check the validity of a capability being read. So any task
which attempts to 'read all things set in bset' followed by 'unset all
things set in bset' will not even attempt to unset the undefined bits
higher than CAP_LAST_CAP.
So the 'parent' will look something like:
CapInh: 0000000000000000
CapPrm: 0000000000000000
CapEff: 0000000000000000
CapBnd: ffffffc000000000
All of this 'should' be fine. Given that these are undefined bits that
aren't supposed to have anything to do with permissions. But they do...
So lets now consider a task which cleared the eff/perm/inh completely
and cleared all of the valid caps in the bset (but not the invalid caps
it couldn't read out of the kernel). We know that this is exactly what
the libcap-ng library does and what the go capabilities library does.
They both leave you in that above situation if you try to clear all of
you capapabilities from all 4 sets. If that root task calls execve()
the child task will pick up all caps not blocked by the bset. The bset
however does not block bits higher than CAP_LAST_CAP. So now the child
task has bits in eff which are not in the parent. These are
'meaningless' undefined bits, but still bits which the parent doesn't
have.
The problem is now in cred_cap_issubset() (or any operation which does a
subset test) as the child, while a subset for valid cap bits, is not a
subset for invalid cap bits! So now we set durring commit creds that
the child is not dumpable. Given it is 'more priv' than its parent. It
also means the parent cannot ptrace the child and other stupidity.
The solution here:
1) stop hiding capability bits in status
This makes debugging easier!
2) stop giving any task undefined capability bits. it's simple, it you
don't put those invalid bits in CAP_FULL_SET you won't get them in init
and you won't get them in any other task either.
This fixes the cap_issubset() tests and resulting fallout (which
made the init task in a docker container untraceable among other
things)
3) mask out undefined bits when sys_capset() is called as it might use
~0, ~0 to denote 'all capabilities' for backward/forward compatibility.
This lets 'capsh --caps="all=eip" -- -c /bin/bash' run.
4) mask out undefined bit when we read a file capability off of disk as
again likely all bits are set in the xattr for forward/backward
compatibility.
This lets 'setcap all+pe /bin/bash; /bin/bash' run
Signed-off-by: Eric Paris <eparis@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Andrew G. Morgan <morgan@kernel.org>
Cc: Serge E. Hallyn <serge.hallyn@canonical.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Steve Grubb <sgrubb@redhat.com>
Cc: Dan Walsh <dwalsh@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
During suspend we call sched_clock_poll() to update the epoch and
accumulated time and reprogram the sched_clock_timer to fire
before the next wrap-around time. Unfortunately,
sched_clock_poll() doesn't restart the timer, instead it relies
on the hrtimer layer to do that and during suspend we aren't
calling that function from the hrtimer layer. Instead, we're
reprogramming the expires time while the hrtimer is enqueued,
which can cause the hrtimer tree to be corrupted. Furthermore, we
restart the timer during suspend but we update the epoch during
resume which seems counter-intuitive.
Let's fix this by saving the accumulated state and canceling the
timer during suspend. On resume we can update the epoch and
restart the timer similar to what we would do if we were starting
the clock for the first time.
Fixes: a08ca5d108 "sched_clock: Use an hrtimer instead of timer"
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1406174630-23458-1-git-send-email-john.stultz@linaro.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
BPF is used in several kernel components. This split creates logical boundary
between generic eBPF core and the rest
kernel/bpf/core.c: eBPF interpreter
net/core/filter.c: classic->eBPF converter, classic verifiers, socket filters
This patch only moves functions.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There's a helper function to get a ring buffer page size (the number
of bytes of data recorded on the page), called rb_page_size().
Use that instead of open coding it.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
By caching the ntp_tick_length() when we correct the frequency error,
and then using that cached value to accumulate error, we avoid large
initial errors when the tick length is changed.
This makes convergence happen much faster in the simulator, since the
initial error doesn't have to be slowly whittled away.
This initially seems like an accounting error, but Miroslav pointed out
that ntp_tick_length() can change mid-tick, so when we apply it in the
error accumulation, we are applying any recent change to the entire tick.
This approach chooses to apply changes in the ntp_tick_length() only to
the next tick, which allows us to calculate the freq correction before
using the new tick length, which avoids accummulating error.
Credit to Miroslav for pointing this out and providing the original patch
this functionality has been pulled out from, along with the rational.
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Reported-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The existing timekeeping_adjust logic has always been complicated
to understand. Further, since it was developed prior to NOHZ becoming
common, its not surprising it performs poorly when NOHZ is enabled.
Since Miroslav pointed out the problematic nature of the existing code
in the NOHZ case, I've tried to refactor the code to perform better.
The problem with the previous approach was that it tried to adjust
for the total cumulative error using a scaled dampening factor. This
resulted in large errors to be corrected slowly, while small errors
were corrected quickly. With NOHZ the timekeeping code doesn't know
how far out the next tick will be, so this results in bad
over-correction to small errors, and insufficient correction to large
errors.
Inspired by Miroslav's patch, I've refactored the code to try to
address the correction in two steps.
1) Check the future freq error for the next tick, and if the frequency
error is large, try to make sure we correct it so it doesn't cause
much accumulated error.
2) Then make a small single unit adjustment to correct any cumulative
error that has collected over time.
This method performs fairly well in the simulator Miroslav created.
Major credit to Miroslav for pointing out the issue, providing the
original patch to resolve this, a simulator for testing, as well as
helping debug and resolve issues in my implementation so that it
performed closer to his original implementation.
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Reported-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
In the GENERIC_TIME_VSYSCALL_OLD update_vsyscall implementation,
we take the tk_xtime() value, which returns a timespec64, and
store it in a timespec.
This luckily is ok, since the only architectures that use
GENERIC_TIME_VSYSCALL_OLD are ia64 and ppc64, which are both
64 bit systems where timespec64 is the same as a timespec.
Even so, for cleanliness reasons, use the conversion function
to assign the proper type.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Expose the new NMI safe accessor to clock monotonic to the tracer.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Tracers want a correlated time between the kernel instrumentation and
user space. We really do not want to export sched_clock() to user
space, so we need to provide something sensible for this.
Using separate data structures with an non blocking sequence count
based update mechanism allows us to do that. The data structure
required for the readout has a sequence counter and two copies of the
timekeeping data.
On the update side:
smp_wmb();
tkf->seq++;
smp_wmb();
update(tkf->base[0], tk);
smp_wmb();
tkf->seq++;
smp_wmb();
update(tkf->base[1], tk);
On the reader side:
do {
seq = tkf->seq;
smp_rmb();
idx = seq & 0x01;
now = now(tkf->base[idx]);
smp_rmb();
} while (seq != tkf->seq)
So if a NMI hits the update of base[0] it will use base[1] which is
still consistent, but this timestamp is not guaranteed to be monotonic
across an update.
The timestamp is calculated by:
now = base_mono + clock_delta * slope
So if the update lowers the slope, readers who are forced to the
not yet updated second array are still using the old steeper slope.
tmono
^
| o n
| o n
| u
| o
|o
|12345678---> reader order
o = old slope
u = update
n = new slope
So reader 6 will observe time going backwards versus reader 5.
While other CPUs are likely to be able observe that, the only way
for a CPU local observation is when an NMI hits in the middle of
the update. Timestamps taken from that NMI context might be ahead
of the following timestamps. Callers need to be aware of that and
deal with it.
V2: Got rid of clock monotonic raw and reorganized the data
structures. Folded in the barrier fix from Mathieu.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
All the function needs is in the tk_read_base struct. No functional
change for the current code, just a preparatory patch for the NMI safe
accessor to clock monotonic which will use struct tk_read_base as well.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The members of the new struct are the required ones for the new NMI
safe accessor to clcok monotonic. In order to reuse the existing
timekeeping code and to make the update of the fast NMI safe
timekeepers a simple memcpy use the struct for the timekeeper as well
and convert all users.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Access to time requires to touch two cachelines at minimum
1) The timekeeper data structure
2) The clocksource data structure
The access to the clocksource data structure can be avoided as almost
all clocksource implementations ignore the argument to the read
callback, which is a pointer to the clocksource.
But the core needs to touch it to access the members @read and @mask.
So we are better off by copying the @read function pointer and the
@mask from the clocksource to the core data structure itself.
For the most used ktime_get() access all required data including the
@read and @mask copies fits together with the sequence counter into a
single 64 byte cacheline.
For the other time access functions we touch in the current code three
cache lines in the worst case. But with the clocksource data copies we
can reduce that to two adjacent cachelines, which is more efficient
than disjunct cache lines.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
cycle_last was added to the clocksource to support the TSC
validation. We moved that to the core code, so we can get rid of the
extra copy.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The only user of the cycle_last validation is the x86 TSC. In order to
provide NMI safe accessor functions for clock monotonic and
monotonic_raw we need to do that in the core.
We can't do the TSC specific
if (now < cycle_last)
now = cycle_last;
for the other wrapping around clocksources, but TSC has
CLOCKSOURCE_MASK(64) which actually does not mask out anything so if
now is less than cycle_last the subtraction will give a negative
result. So we can check for that in clocksource_delta() and return 0
for that case.
Implement and enable it for x86
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
We want to move the TSC sanity check into core code to make NMI safe
accessors to clock monotonic[_raw] possible. For this we need to
sanity check the delta calculation. Create a helper function and
convert all sites to use it.
[ Build fix from jstultz ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Provide a ktime_t based interface for raw monotonic time.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
timekeeping_clocktai() is not used in fast pathes, so the extra
timespec conversion is not problematic.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Subtracting plain nsec values and converting to timespec is simpler
than the whole timespec math. Not really fastpath code, so the
division is not an issue.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
get_monotonic_boottime() is not used in fast pathes, so the extra
timespec conversion is not problematic.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Having two fields within the same struct that is off by one character
can be confusing and error prone. Rename the counter "trampolines"
to "nr_trampolines" to explicitly show it is a counter and not to
be confused by the "trampoline" field.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Converting cputime to timespec and timespec to nanoseconds makes no
sense. Use cputime_to_ns() and be done with it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Kill the timespec juggling and calculate with plain nanoseconds.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Simplify the timespec to nsec/usec conversions.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Simplify the only user of this data by removing the timespec
conversion.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Required for moving drivers to the nanosecond based interfaces.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
ktime based conversion function to map a monotonic time stamp to a
different CLOCK.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Provide a helper function which lets us implement ktime_t based
interfaces for real, boot and tai clocks.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Speed up ktime_get() by using ktime_t based data. Text size shrinks by
64 bytes on x8664.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The ktime_t based interfaces are used a lot in performance critical
code pathes. Add ktime_t based data so the interfaces don't have to
convert from the xtime/timespec based data.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
We already have a function which does the right thing, that also makes
sure that the coming ktime_t based cached values are getting updated.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
struct timekeeper is quite badly sorted for the hot readout path. Most
time access functions need to load two cache lines.
Rearrange it so ktime_get() and getnstimeofday() are happy with a
single cache line.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
To convert callers of the core code to timespec64 we need to provide
the proper interfaces.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Right now we have time related prototypes in 3 different header
files. Move it to a single timekeeping header file and move the core
internal stuff into a core private header.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Convert the core timekeeping logic to use timespec64s. This moves the
2038 issues out of the core logic and into all of the accessor
functions.
Future changes will need to push the timespec64s out to all
timekeeping users, but that can be done interface by interface.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Helper and conversion functions for timespec64.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
With the plain nanoseconds based ktime_t we can simply use
ktime_divns() instead of going through loops and hoops of
timespec/timeval conversion.
Reported-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The non-scalar ktime_t implementation is basically a timespec
which has to be changed to support dates past 2038 on 32bit
systems.
This patch removes the non-scalar ktime_t implementation, forcing
the scalar s64 nanosecond version on all architectures.
This may have additional performance overhead on some 32bit
systems when converting between ktime_t and timespec structures,
however the majority of 32bit systems (arm and i386) were already
using scalar ktime_t, so no performance regressions will be seen
on those platforms.
On affected platforms, I'm open to finding optimizations, including
avoiding converting to timespecs where possible.
[ tglx: We can now cleanup the ktime_t.tv64 mess, but thats a
different issue and we can throw a coccinelle script at it ]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Rather then having two similar but totally different implementations
that provide timekeeping state to the hrtimer code, try to unify the
two implementations to be more simliar.
Thus this clarifies ktime_get_update_offsets to
ktime_get_update_offsets_now and changes get_xtime... to
ktime_get_update_offsets_tick.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Provide a default stub function instead of having the extra
conditional. Cuts binary size on a m68k build by ~100 bytes.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Create a module that allows udelay() to be executed to ensure that
it is delaying at least as long as requested (with a little bit of
error allowed).
There are some configurations which don't have reliably udelay
due to using a loop delay with cpufreq changes which should use
a counter time based delay instead. This test aims to identify
those configurations where timing is unreliable.
Signed-off-by: David Riley <davidriley@chromium.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The PM workqueue is going to be used by ACPI PM notify handlers
regardless of whether or not runtime PM is configured, so move
it out of #ifdef CONFIG_PM_RUNTIME.
Do that in three places in the ACPI device PM code.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
After the introduction of freeze_ops it makes more sense to move
all of the platform suspend operations to separate functions that
each will do all of the necessary checks and choose the right
callback to execute istead of doing all that in the core code
which makes it generally harder to follow.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since the OPP layer is a kernel library which has been converted to be
directly selectable by its callers rather than user selectable and
requiring architectures to enable it explicitly the ARCH_HAS_OPP symbol
has become redundant and can be removed. Do so.
Signed-off-by: Mark Brown <broonie@linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Nishanth Menon <nm@ti.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Shawn Guo <shawn.guo@freescale.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
They are the same and nr_node_ids is provided by the memory subsystem.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
After the locking was moved up to the caller of the get_unbound_pool(),
out_unlock label doesn't need to do any unlock operation and the name
became bad, so we just remove this label, and the only usage-site
"goto out_unlock" is subsituted to "return pool".
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
In 75ccf5950f ("workqueue: prepare flush_workqueue() for dynamic
creation and destrucion of unbound pool_workqueues"), a comment
about the synchronization for the pwq in pwq_unbound_release_workfn()
was added. The comment claimed the flush_mutex wasn't strictly
necessary, it was correct in that time, due to the pwq was protected
by workqueue_lock.
But it is incorrect now since the wq->flush_mutex was renamed to
wq->mutex and workqueue_lock was removed, the wq->mutex is strictly
needed. But the comment was miss-updated when the synchronization
was changed.
This patch removes the incorrect comments and doesn't add any new
comment to explain why wq->mutex is needed here, which is definitely
obvious and wq->pwqs_node has "WQ" notation in its definition which is
better comment.
The old commit mentioned above also introduced a comment in link_pwq()
about the synchronization. This comment is also removed in this patch
since the whole link_pwq() is proteced by wq->mutex.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
In 51697d3939 ("workqueue: use generic attach/detach routine for
rescuers"), The rescuer detaches itself from the pool before put_pwq()
so that the put_unbound_pool() will not destroy the rescuer-attached
pool.
It is unnecessary. worker_detach_from_pool() can be used as the last
statement to access to the pool just like the regular workers,
put_unbound_pool() will wait for it to detach and then free the pool.
So we move the worker_detach_from_pool() down, make it coincide with
the regular workers.
tj: Minor description update.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Simply unfold the code of start_worker() into create_worker() and
remove the original start_worker() and create_and_start_worker().
The only trade-off is the introduced overhead that the pool->lock
is released and regrabbed after the newly worker is started.
The overhead is acceptible since the manager is slow path.
And because this new locking behavior, the newly created worker
may grab the lock earlier than the manager and go to process
work items. In this case, the recheck need_to_create_worker() may be
true as expected and the manager goes to restart which is the
correct behavior.
tj: Minor updates to description and comments.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
worker_set_flags() has only two callers, each specifying %true and
%false for @wakeup. Let's push the wake up to the caller and remove
@wakeup from worker_set_flags(). The caller can use the following
instead if wakeup is necessary:
worker_set_flags();
if (need_more_worker(pool))
wake_up_worker(pool);
This makes the code simpler. This patch doesn't introduce behavior
changes.
tj: Updated description and comments.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
In process_one_work():
if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool))
wake_up_worker(pool);
the first test is unneeded. Even if the first test is removed, it
doesn't affect the wake-up logic for WORKER_UNBOUND, and it will not
introduce any useless wake-ups for normal per-cpu workers since
nr_running is always >= 1. It will introduce useless/redundant
wake-ups for CPU_INTENSIVE, but this case is rare and the next patch
will also remove this redundant wake-up.
tj: Minor updates to the description and comment.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Conflicts:
drivers/infiniband/hw/cxgb4/device.c
The cxgb4 conflict was simply overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
The "uptime" trace clock added in:
commit 8aacf017b0
tracing: Add "uptime" trace clock that uses jiffies
has wraparound problems when the system has been up more
than 1 hour 11 minutes and 34 seconds. It converts jiffies
to nanoseconds using:
(u64)jiffies_to_usecs(jiffy) * 1000ULL
but since jiffies_to_usecs() only returns a 32-bit value, it
truncates at 2^32 microseconds. An additional problem on 32-bit
systems is that the argument is "unsigned long", so fixing the
return value only helps until 2^32 jiffies (49.7 days on a HZ=1000
system).
Avoid these problems by using jiffies_64 as our basis, and
not converting to nanoseconds (we do convert to clock_t because
user facing API must not be dependent on internal kernel
HZ values).
Link: http://lkml.kernel.org/p/99d63c5bfe9b320a3b428d773825a37095bf6a51.1405708254.git.tony.luck@intel.com
Cc: stable@vger.kernel.org # 3.10+
Fixes: 8aacf017b0 "tracing: Add "uptime" trace clock that uses jiffies"
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Simplify the sleep states sysfs interface /sys/power/state code by
redefining pm_states[] as an array of pointers to constant strings
such that only the entries corresponding to valid states are set.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull locking fixes from Thomas Gleixner:
"The locking department delivers:
- A rather large and intrusive bundle of fixes to address serious
performance regressions introduced by the new rwsem / mcs
technology. Simpler solutions have been discussed, but they would
have been ugly bandaids with more risk than doing the right thing.
- Make the rwsem spin on owner technology opt-in for architectures
and enable it only on the known to work ones.
- A few fixes to the lockdep userspace library"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER
locking/mutex: Disable optimistic spinning on some architectures
locking/rwsem: Reduce the size of struct rw_semaphore
locking/rwsem: Rename 'activity' to 'count'
locking/spinlocks/mcs: Micro-optimize osq_unlock()
locking/spinlocks/mcs: Introduce and use init macro and function for osq locks
locking/spinlocks/mcs: Convert osq lock to atomic_t to reduce overhead
locking/spinlocks/mcs: Rename optimistic_spin_queue() to optimistic_spin_node()
locking/rwsem: Allow conservative optimistic spinning when readers have lock
tools/liblockdep: Account for bitfield changes in lockdeps lock_acquire
tools/liblockdep: Remove debug print left over from development
tools/liblockdep: Fix comparison of a boolean value with a value of 2
Pull scheduler fix from Thomas Gleixner:
"Prevent a possible divide by zero in the debugging code"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched: Fix possible divide by zero in avg_atom() calculation
Pull timer fix from Thomas Gleixner:
"A single fix for a long standing issue in the alarm timer subsystem,
which was noticed recently when people finally started to use alarm
timers for serious work"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
alarmtimer: Fix bug where relative alarm timers were treated as absolute
Pull RCU fixes from Thomas Gleixner:
"Two RCU patches:
- Address a serious performance regression on open/close caused by
commit ac1bea8578 ("Make cond_resched() report RCU quiescent
states")
- Export RCU debug functions. Not a regression, but enablement to
address a serious recursion bug in the sl*b allocators in 3.17"
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
rcu: Reduce overhead of cond_resched() checks for RCU
rcu: Export debug_init_rcu_head() and and debug_init_rcu_head()
- Fix for a recently introduced NULL pointer dereference in the core
system suspend code occuring when platforms without ACPI attempt to
use the "freeze" sleep state from Zhang Rui.
- Fix for a recently introduced build warning in cpufreq headers from
Brian W Hart.
- Fix for a 3.13 cpufreq regression related to sysem resume that
triggers on some systems with multiple CPU clusters from Viresh Kumar.
- Fix for a 3.4 regression in request_firmware() resulting in
WARN_ON()s on some systems during system resume from Takashi Iwai.
- Revert of the ACPI video commit that changed the default value of
the video.brightness_switch_enabled command line argument to 0 as
it has been reported to break existing setups.
- ACPI device enumeration documentation update to take recent code
changes into account and make the documentation match the code again
from Darren Hart.
- Fixes for the sa1110, imx6q, kirkwood, and cpu0 cpufreq drivers
from Linus Walleij, Nicolas Del Piano, Quentin Armitage, Viresh Kumar.
- New ACPI video blacklist entry for HP ProBook 4540s from Hans de Goede.
/
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Merge tag 'pm+acpi-3.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management fixes from Rafael Wysocki:
"These are a few recent regression fixes, a revert of the ACPI video
commit I promised, a system resume fix related to request_firmware(),
an ACPI video quirk for one more Win8-oriented BIOS, an ACPI device
enumeration documentation update and a few fixes for ARM cpufreq
drivers.
Specifics:
- Fix for a recently introduced NULL pointer dereference in the core
system suspend code occuring when platforms without ACPI attempt to
use the "freeze" sleep state from Zhang Rui.
- Fix for a recently introduced build warning in cpufreq headers from
Brian W Hart.
- Fix for a 3.13 cpufreq regression related to sysem resume that
triggers on some systems with multiple CPU clusters from Viresh
Kumar.
- Fix for a 3.4 regression in request_firmware() resulting in
WARN_ON()s on some systems during system resume from Takashi Iwai.
- Revert of the ACPI video commit that changed the default value of
the video.brightness_switch_enabled command line argument to 0 as
it has been reported to break existing setups.
- ACPI device enumeration documentation update to take recent code
changes into account and make the documentation match the code
again from Darren Hart.
- Fixes for the sa1110, imx6q, kirkwood, and cpu0 cpufreq drivers
from Linus Walleij, Nicolas Del Piano, Quentin Armitage, Viresh
Kumar.
- New ACPI video blacklist entry for HP ProBook 4540s from Hans de
Goede"
* tag 'pm+acpi-3.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: make table sentinel macros unsigned to match use
cpufreq: move policy kobj to policy->cpu at resume
cpufreq: cpu0: OPPs can be populated at runtime
cpufreq: kirkwood: Reinstate cpufreq driver for ARCH_KIRKWOOD
cpufreq: imx6q: Select PM_OPP
cpufreq: sa1110: set memory type for h3600
ACPI / video: Add use_native_backlight quirk for HP ProBook 4540s
PM / sleep: fix freeze_ops NULL pointer dereferences
PM / sleep: Fix request_firmware() error at resume
Revert "ACPI / video: change acpi-video brightness_switch_enabled default to 0"
ACPI / documentation: Remove reference to acpi_platform_device_ids from enumeration.txt
We don't need to wake up regular worker when nr_running==1,
so need_more_worker() is sufficient here.
And need_more_worker() gives us better readability due to the name of
"keep_working()" implies the rescuer should keep working now but
the rescuer is actually leaving.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Do not waste time copying the old hash if the hash is going to be
reset. Just allocate a new hash and free the old one, as that is
the same result as copying te old one and then resetting it.
Link: http://lkml.kernel.org/p/1405384820-48837-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Wang Nan <wangnan0@huawei.com>
[ SDR: Removed unused ftrace_filter_reset() function ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently, tracing_thresh works only if we specify it before selecting
function_graph tracer. If we do the opposite, tracing_thresh will change
it's value, but it will not be applied.
To fix it, we add update_thresh callback which is called whenever
tracing_thresh is updated and for function_graph tracer we register
handler which reinitializes tracer depending on tracing_thresh.
Link: http://lkml.kernel.org/p/20140718111727.GA3206@stfomichev-desktop.yandex.net
Signed-off-by: Stanislav Fomichev <stfomichev@yandex-team.ru>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Applying restrictive seccomp filter programs to large or diverse
codebases often requires handling threads which may be started early in
the process lifetime (e.g., by code that is linked in). While it is
possible to apply permissive programs prior to process start up, it is
difficult to further restrict the kernel ABI to those threads after that
point.
This change adds a new seccomp syscall flag to SECCOMP_SET_MODE_FILTER for
synchronizing thread group seccomp filters at filter installation time.
When calling seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_TSYNC,
filter) an attempt will be made to synchronize all threads in current's
threadgroup to its new seccomp filter program. This is possible iff all
threads are using a filter that is an ancestor to the filter current is
attempting to synchronize to. NULL filters (where the task is running as
SECCOMP_MODE_NONE) are also treated as ancestors allowing threads to be
transitioned into SECCOMP_MODE_FILTER. If prctrl(PR_SET_NO_NEW_PRIVS,
...) has been set on the calling thread, no_new_privs will be set for
all synchronized threads too. On success, 0 is returned. On failure,
the pid of one of the failing threads will be returned and no filters
will have been applied.
The race conditions against another thread are:
- requesting TSYNC (already handled by sighand lock)
- performing a clone (already handled by sighand lock)
- changing its filter (already handled by sighand lock)
- calling exec (handled by cred_guard_mutex)
The clone case is assisted by the fact that new threads will have their
seccomp state duplicated from their parent before appearing on the tasklist.
Holding cred_guard_mutex means that seccomp filters cannot be assigned
while in the middle of another thread's exec (potentially bypassing
no_new_privs or similar). The call to de_thread() may kill threads waiting
for the mutex.
Changes across threads to the filter pointer includes a barrier.
Based on patches by Will Drewry.
Suggested-by: Julien Tinnes <jln@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
This changes the mode setting helper to allow threads to change the
seccomp mode from another thread. We must maintain barriers to keep
TIF_SECCOMP synchronized with the rest of the seccomp state.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Normally, task_struct.seccomp.filter is only ever read or modified by
the task that owns it (current). This property aids in fast access
during system call filtering as read access is lockless.
Updating the pointer from another task, however, opens up race
conditions. To allow cross-thread filter pointer updates, writes to the
seccomp fields are now protected by the sighand spinlock (which is shared
by all threads in the thread group). Read access remains lockless because
pointer updates themselves are atomic. However, writes (or cloning)
often entail additional checking (like maximum instruction counts)
which require locking to perform safely.
In the case of cloning threads, the child is invisible to the system
until it enters the task list. To make sure a child can't be cloned from
a thread and left in a prior state, seccomp duplication is additionally
moved under the sighand lock. Then parent and child are certain have
the same seccomp state when they exit the lock.
Based on patches by Will Drewry and David Drysdale.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
In preparation for adding seccomp locking, move filter creation away
from where it is checked and applied. This will allow for locking where
no memory allocation is happening. The validation, filter attachment,
and seccomp mode setting can all happen under the future locks.
For extreme defensiveness, I've added a BUG_ON check for the calculated
size of the buffer allocation in case BPF_MAXINSN ever changes, which
shouldn't ever happen. The compiler should actually optimize out this
check since the test above it makes it impossible.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Since seccomp transitions between threads requires updates to the
no_new_privs flag to be atomic, the flag must be part of an atomic flag
set. This moves the nnp flag into a separate task field, and introduces
accessors.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
This adds the new "seccomp" syscall with both an "operation" and "flags"
parameter for future expansion. The third argument is a pointer value,
used with the SECCOMP_SET_MODE_FILTER operation. Currently, flags must
be 0. This is functionally equivalent to prctl(PR_SET_SECCOMP, ...).
In addition to the TSYNC flag later in this patch series, there is a
non-zero chance that this syscall could be used for configuring a fixed
argument area for seccomp-tracer-aware processes to pass syscall arguments
in the future. Hence, the use of "seccomp" not simply "seccomp_add_filter"
for this syscall. Additionally, this syscall uses operation, flags,
and user pointer for arguments because strictly passing arguments via
a user pointer would mean seccomp itself would be unable to trivially
filter the seccomp syscall itself.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Separates the two mode setting paths to make things more readable with
fewer #ifdefs within function bodies.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
To support splitting mode 1 from mode 2, extract the mode checking and
assignment logic into common functions.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
In preparation for having other callers of the seccomp mode setting
logic, split the prctl entry point away from the core logic that performs
seccomp mode setting.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
The code for resizing the trace ring buffers has to run the per-cpu
resize on the CPU itself. The code was using preempt_off() and
running the code for the current CPU directly, otherwise calling
schedule_work_on().
At least on RT this could result in the following:
|BUG: sleeping function called from invalid context at kernel/rtmutex.c:673
|in_atomic(): 1, irqs_disabled(): 0, pid: 607, name: bash
|3 locks held by bash/607:
|CPU: 0 PID: 607 Comm: bash Not tainted 3.12.15-rt25+ #124
|(rt_spin_lock+0x28/0x68)
|(free_hot_cold_page+0x84/0x3b8)
|(free_buffer_page+0x14/0x20)
|(rb_update_pages+0x280/0x338)
|(ring_buffer_resize+0x32c/0x3dc)
|(free_snapshot+0x18/0x38)
|(tracing_set_tracer+0x27c/0x2ac)
probably via
|cd /sys/kernel/debug/tracing/
|echo 1 > events/enable ; sleep 2
|echo 1024 > buffer_size_kb
If we just always use schedule_work_on(), there's no need for the
preempt_off(). So do that.
Link: http://lkml.kernel.org/p/1405537633-31518-1-git-send-email-cminyard@mvista.com
Reported-by: Stanislav Meduna <stano@meduna.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
All users of function_trace_stop and HAVE_FUNCTION_TRACE_MCOUNT_TEST have
been removed. We can safely remove them from the kernel.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
function_trace_stop is no longer used to stop function tracing.
Remove the check from __ftrace_ops_list_func().
Also, call FTRACE_WARN_ON() instead of setting function_trace_stop
if a ops has no func to call.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When function tracing is being updated function_trace_stop is set to
keep from tracing the updates. This was fine when function tracing
was done from stop machine. But it is no longer done that way and
this can cause real tracing to be missed.
Remove it.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
All archs now use ftrace_graph_is_dead() to stop function graph
tracing. Remove the usage of ftrace_stop() as that is no longer
needed.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
On ia64 and ppc64, function pointers do not point to the
entry address of the function, but to the address of a
function descriptor (which contains the entry address and misc
data).
Since the kprobes code passes the function pointer stored
by NOKPROBE_SYMBOL() to kallsyms_lookup_size_offset() for
initalizing its blacklist, it fails and reports many errors,
such as:
Failed to find blacklist 0001013168300000
Failed to find blacklist 0001013000f0a000
[...]
To fix this bug, use arch_deref_entry_point() to get the
function entry address for kallsyms_lookup_size_offset()
instead of the raw function pointer.
Suzuki also pointed out that blacklist entries should also
be updated as well.
Reported-by: Tony Luck <tony.luck@gmail.com>
Fixed-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (for powerpc)
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: sparse@chrisli.org
Cc: Paul Mackerras <paulus@samba.org>
Cc: akataria@vmware.com
Cc: anil.s.keshavamurthy@intel.com
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Kevin Hao <haokexin@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: rdunlap@infradead.org
Cc: dl9pf@gmx.de
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: linux-ia64@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/20140717114411.13401.2632.stgit@kbuild-fedora.novalocal
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Some driver might want to pass in an 64-bit value, so introduce
a module param type 'ullong'.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Ewan Milne <emilne@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Christoph Hellwig <hch@lst.de>
I was cleaning out my INBOX and found two fixes from zhangwei from
a year ago that were lost in my mail. These fix an inconsistency between
trace_puts() and the way trace_printk() works. The reason this is
important to fix is because when trace_printk() doesn't have any
arguments, it turns into a trace_puts(). Not being able to enable a
stack trace against trace_printk() because it does not have any arguments
is quite confusing. Also, the fix is rather trivial and low risk.
While porting some changes to PowerPC I discovered that it still has
the function graph tracer filter bug that if you also enable stack tracing
the function graph tracer filter is ignored. I fixed that up.
Finally, Martin Lau, fixed a bug that would cause readers of the
ftrace ring buffer to block forever even though it was suppose to be
NONBLOCK.
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Merge tag 'trace-fixes-v3.16-rc5-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"A few more fixes for ftrace infrastructure.
I was cleaning out my INBOX and found two fixes from zhangwei from a
year ago that were lost in my mail. These fix an inconsistency
between trace_puts() and the way trace_printk() works. The reason
this is important to fix is because when trace_printk() doesn't have
any arguments, it turns into a trace_puts(). Not being able to enable
a stack trace against trace_printk() because it does not have any
arguments is quite confusing. Also, the fix is rather trivial and low
risk.
While porting some changes to PowerPC I discovered that it still has
the function graph tracer filter bug that if you also enable stack
tracing the function graph tracer filter is ignored. I fixed that up.
Finally, Martin Lau, fixed a bug that would cause readers of the
ftrace ring buffer to block forever even though it was suppose to be
NONBLOCK"
This also includes the fix from an earlier pull request:
"Oleg Nesterov fixed a memory leak that happens if a user creates a
tracing instance, sets up a filter in an event, and then removes that
instance. The filter allocates memory that is never freed when the
instance is destroyed"
* tag 'trace-fixes-v3.16-rc5-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ring-buffer: Fix polling on trace_pipe
tracing: Add TRACE_ITER_PRINTK flag check in __trace_puts/__trace_bputs
tracing: Fix graph tracer with stack tracer on other archs
tracing: Add ftrace_trace_stack into __trace_puts/__trace_bputs
tracing: instance_rmdir() leaks ftrace_event_file->filter
ftrace_stop() is going away as it disables parts of function tracing
that affects users that should not be affected. But ftrace_graph_stop()
is built on ftrace_stop(). Here's another example of killing all of
function tracing because something went wrong with function graph
tracing.
Instead of disabling all users of function tracing on function graph
error, disable only function graph tracing.
A new function is created called ftrace_graph_is_dead(). This is called
in strategic paths to prevent function graph from doing more harm and
allowing at least a warning to be printed before the system crashes.
NOTE: ftrace_stop() is still used until all the archs are converted over
to use ftrace_graph_is_dead(). After that, ftrace_stop() will be removed.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
ftrace_stop() and ftrace_start() were added to the suspend and hibernate
process because there was some function within the work flow that caused
the system to reboot if it was traced. This function has recently been
found (restore_processor_state()). Now there's no reason to disable
function tracing while we are going into suspend or hibernate, which means
that being able to trace this will help tremendously in debugging any
issues with suspend or hibernate.
This also means that the ftrace_stop/start() functions can be removed
and simplify the function tracing code a bit.
Link: http://lkml.kernel.org/r/1518201.VD9cU33jRU@vostro.rjw.lan
Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Instead of allowing public keys, with certificates signed by any
key on the system trusted keyring, to be added to a trusted keyring,
this patch further restricts the certificates to those signed only by
builtin keys on the system keyring.
This patch defines a new option 'builtin' for the kernel parameter
'keys_ownerid' to allow trust validation using builtin keys.
Simplified Mimi's "KEYS: define an owner trusted keyring" patch
Changelog v7:
- rename builtin_keys to use_builtin_keys
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Export the generic irq map function in order to provide irq_domain ops with
generic mapping and specific of xlate function (needed by the new atmel
AIC driver).
Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1405012462-766-2-git-send-email-boris.brezillon@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
The arch_mutex_cpu_relax() function, introduced by 34b133f, is
hacky and ugly. It was added a few years ago to address the fact
that common cpu_relax() calls include yielding on s390, and thus
impact the optimistic spinning functionality of mutexes. Nowadays
we use this function well beyond mutexes: rwsem, qrwlock, mcs and
lockref. Since the macro that defines the call is in the mutex header,
any users must include mutex.h and the naming is misleading as well.
This patch (i) renames the call to cpu_relax_lowlatency ("relax, but
only if you can do it with very low latency") and (ii) defines it in
each arch's asm/processor.h local header, just like for regular cpu_relax
functions. On all archs, except s390, cpu_relax_lowlatency is simply cpu_relax,
and thus we can take it out of mutex.h. While this can seem redundant,
I believe it is a good choice as it allows us to move out arch specific
logic from generic locking primitives and enables future(?) archs to
transparently define it, similarly to System Z.
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bharat Bhushan <r65777@freescale.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Joseph Myers <joseph@codesourcery.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Qiaowei Ren <qiaowei.ren@intel.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Stratos Karafotis <stratosk@semaphore.gr>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Kulikov <segoon@openwall.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: Waiman Long <Waiman.Long@hp.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: adi-buildroot-devel@lists.sourceforge.net
Cc: linux390@de.ibm.com
Cc: linux-alpha@vger.kernel.org
Cc: linux-am33-list@redhat.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-cris-kernel@axis.com
Cc: linux-hexagon@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux@lists.openrisc.net
Cc: linux-m32r-ja@ml.linux-m32r.org
Cc: linux-m32r@ml.linux-m32r.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-metag@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/1404079773.2619.4.camel@buesod1.americas.hpqcorp.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When lockdep turns itself off, the following message is logged:
Please attach the output of /proc/lock_stat to the bug report
Omit this message when CONFIG_LOCK_STAT is off, and /proc/lock_stat
doesn't exist.
Signed-off-by: Andreas Gruenbacher <andreas.gruenbacher@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1405451452-3824-1-git-send-email-andreas.gruenbacher@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull perf fixes from Ingo Molnar:
"Tooling fixes and an Intel PMU driver fixlet"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Do not allow optimized switch for non-cloned events
perf/x86/intel: ignore CondChgd bit to avoid false NMI handling
perf symbols: Get kernel start address by symbol name
perf tools: Fix segfault in cumulative.callchain report
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Merge tag 'v3.16-rc5' into timers/core
Reason: Bring in upstream modifications, so the pending changes which
depend on them can be queued.
Cosmetic, but replace_preds() doesn't need/use "char *filter_string".
Remove it to microsimplify the code.
Link: http://lkml.kernel.org/p/20140715184832.GA20519@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
filter_free_subsystem_preds(), filter_free_subsystem_filters() and
replace_system_preds() can simply check file->system->subsystem and
avoid strcmp(call->class->system).
Better yet, we can pass "struct ftrace_subsystem_dir *dir" instead of
event_subsystem and just check file->system == dir.
Thanks to Namhyung Kim who pointed out that replace_system_preds() can
be changed too.
Link: http://lkml.kernel.org/p/20140715184829.GA20516@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
alloc_trace_uprobe() sets TRACE_EVENT_FL_USE_CALL_FILTER for unknown
reason and this is simply wrong. Fortunately this has no effect because
register_uprobe_event() clears call->flags after that.
Kill both. This trace_uprobe was kzalloc'ed and we rely on this fact
anyway.
Link: http://lkml.kernel.org/p/20140715184824.GA20505@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
It seems that the only purpose of call_filter_disable() is to
make filter_disable() less clear and symmetrical, remove it.
Link: http://lkml.kernel.org/p/20140715184821.GA20498@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Remove destroy_call_preds(). Its only caller, __trace_remove_event_call(),
can use free_event_filter() and nullify ->filter by hand.
Perhaps we could keep this trivial helper although imo it is pointless, but
then it should be static in trace_events.c.
Link: http://lkml.kernel.org/p/20140715184816.GA20495@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
destroy_preds() makes no sense.
The only caller, event_remove(), actually wants destroy_file_preds().
__trace_remove_event_call() does destroy_call_preds() which takes care
of call->filter.
And after the previous change we can simply remove destroy_preds() from
event_remove(), we are going to call remove_event_from_tracers() which
in turn calls remove_event_file_dir()->free_event_filter().
Link: http://lkml.kernel.org/p/20140715184813.GA20488@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If there isn't a nohz_full= kernel parameter specified, then
tick_nohz_full_mask can legitimately be NULL. This can cause
problems when RCU's boot code tries to cpumask_or() this value into
rcu_nocb_mask. In addition, if NO_HZ_FULL_ALL=y, there is no point
in doing the cpumask_or() in the first place because this will cause
RCU_NOCB_CPU_ALL=y, which in turn will have all bits already set in
rcu_nocb_mask.
This commit therefore avoids the cpumask_or() if NO_HZ_FULL_ALL=y
and checks for !tick_nohz_full_running otherwise, this latter check
catching cases when there was no nohz_full= kernel parameter specified.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently if an arch supports function graph tracing, the core code will
just assign the function graph trampoline to the function graph addr that
gets called.
But as the old method for function graph tracing always calls the function
trampoline first and that calls the function graph trampoline, some
archs may have the function graph trampoline dependent on operations that
were done in the function trampoline. This causes function graph tracer
to break on those archs.
Instead of having the default be to set the function graph ftrace_ops
to the function graph trampoline, have it instead just set it to zero
which will keep it from jumping to a trampoline that is not set up
to be jumped directly too.
Link: http://lkml.kernel.org/r/53BED155.9040607@nvidia.com
Reported-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com>
Tested-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
It is currently not possible for various wait_on_bit functions
to implement a timeout.
While the "action" function that is called to do the waiting
could certainly use schedule_timeout(), there is no way to carry
forward the remaining timeout after a false wake-up.
As false-wakeups a clearly possible at least due to possible
hash collisions in bit_waitqueue(), this is a real problem.
The 'action' function is currently passed a pointer to the word
containing the bit being waited on. No current action functions
use this pointer. So changing it to something else will be a
little noisy but will have no immediate effect.
This patch changes the 'action' function to take a pointer to
the "struct wait_bit_key", which contains a pointer to the word
containing the bit so nothing is really lost.
It also adds a 'private' field to "struct wait_bit_key", which
is initialized to zero.
An action function can now implement a timeout with something
like
static int timed_out_waiter(struct wait_bit_key *key)
{
unsigned long waited;
if (key->private == 0) {
key->private = jiffies;
if (key->private == 0)
key->private -= 1;
}
waited = jiffies - key->private;
if (waited > 10 * HZ)
return -EAGAIN;
schedule_timeout(waited - 10 * HZ);
return 0;
}
If any other need for context in a waiter were found it would be
easy to use ->private for some other purpose, or even extend
"struct wait_bit_key".
My particular need is to support timeouts in nfs_release_page()
to avoid deadlocks with loopback mounted NFS.
While wait_on_bit_timeout() would be a cleaner interface, it
will not meet my need. I need the timeout to be sensitive to
the state of the connection with the server, which could change.
So I need to use an 'action' interface.
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051604.28027.41257.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The current "wait_on_bit" interface requires an 'action'
function to be provided which does the actual waiting.
There are over 20 such functions, many of them identical.
Most cases can be satisfied by one of just two functions, one
which uses io_schedule() and one which just uses schedule().
So:
Rename wait_on_bit and wait_on_bit_lock to
wait_on_bit_action and wait_on_bit_lock_action
to make it explicit that they need an action function.
Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io
which are *not* given an action function but implicitly use
a standard one.
The decision to error-out if a signal is pending is now made
based on the 'mode' argument rather than being encoded in the action
function.
All instances of the old wait_on_bit and wait_on_bit_lock which
can use the new version have been changed accordingly and their
action functions have been discarded.
wait_on_bit{_lock} does not return any specific error code in the
event of a signal so the caller must check for non-zero and
interpolate their own error code as appropriate.
The wait_on_bit() call in __fscache_wait_on_invalidate() was
ambiguous as it specified TASK_UNINTERRUPTIBLE but used
fscache_wait_bit_interruptible as an action function.
David Howells confirms this should be uniformly
"uninterruptible"
The main remaining user of wait_on_bit{,_lock}_action is NFS
which needs to use a freezer-aware schedule() call.
A comment in fs/gfs2/glock.c notes that having multiple 'action'
functions is useful as they display differently in the 'wchan'
field of 'ps'. (and /proc/$PID/wchan).
As the new bit_wait{,_io} functions are tagged "__sched", they
will not show up at all, but something higher in the stack. So
the distinction will still be visible, only with different
function names (gds2_glock_wait versus gfs2_glock_dq_wait in the
gfs2/glock.c case).
Since first version of this patch (against 3.15) two new action
functions appeared, on in NFS and one in CIFS. CIFS also now
uses an action function that makes the same freezer aware
schedule call as NFS.
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: David Howells <dhowells@redhat.com> (fscache, keys)
Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2)
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Just like with mutexes (CONFIG_MUTEX_SPIN_ON_OWNER),
encapsulate the dependencies for rwsem optimistic spinning.
No logical changes here as it continues to depend on both
SMP and the XADD algorithm variant.
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Acked-by: Jason Low <jason.low2@hp.com>
[ Also make it depend on ARCH_SUPPORTS_ATOMIC_RMW. ]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1405112406-13052-2-git-send-email-davidlohr@hp.com
Cc: aswin@hp.com
Cc: Chris Mason <clm@fb.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Josef Bacik <jbacik@fusionio.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The optimistic spin code assumes regular stores and cmpxchg() play nice;
this is found to not be true for at least: parisc, sparc32, tile32,
metag-lock1, arc-!llsc and hexagon.
There is further wreckage, but this in particular seemed easy to
trigger, so blacklist this.
Opt in for known good archs.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: David Miller <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: John David Anglin <dave.anglin@bell.net>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: stable@vger.kernel.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/20140606175316.GV13930@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are two definitions of struct rw_semaphore, one in linux/rwsem.h
and one in linux/rwsem-spinlock.h.
For some reason they have different names for the initial field. This
makes it impossible to use C99 named initialization for
__RWSEM_INITIALIZER() -- or we have to duplicate that entire thing
along with the structure definitions.
The simpler patch is renaming the rwsem-spinlock variant to match the
regular rwsem.
This allows us to switch to C99 named initialization.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-bmrZolsbGmautmzrerog27io@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Due to divergent trees, Rik find that this patch is no longer
required.
Requested-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-u6odkgkw8wz3m7orgsjfo5pi@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
As pointed out by Andi Kleen, the usage of static keys can be racy in
sched_feat_disable() vs. sched_feat_enable(). Currently, we first check the
value of keys->enabled, and subsequently update the branch direction. This,
can be racy and can potentially leave the keys in an inconsistent state.
Take the i_mutex around these calls to resolve the race.
Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/9d7780c83db26683955cd01e6bc654ee2586e67f.1404315388.git.jbaron@akamai.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We always use resched_task() with rq->curr argument.
It's not possible to reschedule any task but rq's current.
The patch introduces resched_curr(struct rq *) to
replace all of the repeating patterns. The main aim
is cleanup, but there is a little size profit too:
(before)
$ size kernel/sched/built-in.o
text data bss dec hex filename
155274 16445 7042 178761 2ba49 kernel/sched/built-in.o
$ size vmlinux
text data bss dec hex filename
7411490 1178376 991232 9581098 92322a vmlinux
(after)
$ size kernel/sched/built-in.o
text data bss dec hex filename
155130 16445 7042 178617 2b9b9 kernel/sched/built-in.o
$ size vmlinux
text data bss dec hex filename
7411362 1178376 991232 9580970 9231aa vmlinux
I was choosing between resched_curr() and resched_rq(),
and the first name looks better for me.
A little lie in Documentation/trace/ftrace.txt. I have not
actually collected the tracing again. With a hope the patch
won't make execution times much worse :)
Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20140628200219.1778.18735.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
proc_sched_show_task() does:
if (nr_switches)
do_div(avg_atom, nr_switches);
nr_switches is unsigned long and do_div truncates it to 32 bits, which
means it can test non-zero on e.g. x86-64 and be truncated to zero for
division.
Fix the problem by using div64_ul() instead.
As a side effect calculations of avg_atom for big nr_switches are now correct.
Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1402750809-31991-1-git-send-email-mguzik@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The following patch added another way to get mmap name: 78d683e838
("mm, fs: Add vm_ops->name as an alternative to arch_vma_name")
The vdso vma mapping already switch to this and we no longer get vdso
name via arch_vma_name function. Adding this way to the perf mmap
event name retrieval code.
Caught this via perf test:
$ sudo ./perf test -v 7
7: Validate PERF_RECORD_* events & perf_sample fields :
--- start ---
SNIP
PERF_RECORD_MMAP for [vdso] missing!
test child finished with 255
---- end ----
Validate PERF_RECORD_* events & perf_sample fields: FAILED!
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1405353439-14211-1-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In the unlock function of the cancellable MCS spinlock, the first
thing we do is to retrive the current CPU's osq node. However, due to
the changes made in the previous patch, in the common case where the
lock is not contended, we wouldn't need to access the current CPU's
osq node anymore.
This patch optimizes this by only retriving this CPU's osq node
after we attempt the initial cmpxchg to unlock the osq and found
that its contended.
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1405358872-3732-5-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently, we initialize the osq lock by directly setting the lock's values. It
would be preferable if we use an init macro to do the initialization like we do
with other locks.
This patch introduces and uses a macro and function for initializing the osq lock.
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fusionio.com>
Link: http://lkml.kernel.org/r/1405358872-3732-4-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The cancellable MCS spinlock is currently used to queue threads that are
doing optimistic spinning. It uses per-cpu nodes, where a thread obtaining
the lock would access and queue the local node corresponding to the CPU that
it's running on. Currently, the cancellable MCS lock is implemented by using
pointers to these nodes.
In this patch, instead of operating on pointers to the per-cpu nodes, we
store the CPU numbers in which the per-cpu nodes correspond to in atomic_t.
A similar concept is used with the qspinlock.
By operating on the CPU # of the nodes using atomic_t instead of pointers
to those nodes, this can reduce the overhead of the cancellable MCS spinlock
by 32 bits (on 64 bit systems).
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Chris Mason <clm@fb.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Josef Bacik <jbacik@fusionio.com>
Link: http://lkml.kernel.org/r/1405358872-3732-3-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently, the per-cpu nodes structure for the cancellable MCS spinlock is
named "optimistic_spin_queue". However, in a follow up patch in the series
we will be introducing a new structure that serves as the new "handle" for
the lock. It would make more sense if that structure is named
"optimistic_spin_queue". Additionally, since the current use of the
"optimistic_spin_queue" structure are "nodes", it might be better if we
rename them to "node" anyway.
This preparatory patch renames all current "optimistic_spin_queue"
to "optimistic_spin_node".
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Chris Mason <clm@fb.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Josef Bacik <jbacik@fusionio.com>
Link: http://lkml.kernel.org/r/1405358872-3732-2-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 4fc828e24c ("locking/rwsem: Support optimistic spinning")
introduced a major performance regression for workloads such as
xfs_repair which mix read and write locking of the mmap_sem across
many threads. The result was xfs_repair ran 5x slower on 3.16-rc2
than on 3.15 and using 20x more system CPU time.
Perf profiles indicate in some workloads that significant time can
be spent spinning on !owner. This is because we don't set the lock
owner when readers(s) obtain the rwsem.
In this patch, we'll modify rwsem_can_spin_on_owner() such that we'll
return false if there is no lock owner. The rationale is that if we
just entered the slowpath, yet there is no lock owner, then there is
a possibility that a reader has the lock. To be conservative, we'll
avoid spinning in these situations.
This patch reduced the total run time of the xfs_repair workload from
about 4 minutes 24 seconds down to approximately 1 minute 26 seconds,
back to close to the same performance as on 3.15.
Retesting of AIM7, which were some of the workloads used to test the
original optimistic spinning code, confirmed that we still get big
performance gains with optimistic spinning, even with this additional
regression fix. Davidlohr found that while the 'custom' workload took
a performance hit of ~-14% to throughput for >300 users with this
additional patch, the overall gain with optimistic spinning is
still ~+45%. The 'disk' workload even improved by ~+15% at >1000 users.
Tested-by: Dave Chinner <dchinner@redhat.com>
Acked-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1404532172.2572.30.camel@j-VirtualBox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Vince reported that commit 15a2d4de0e ("perf: Always destroy groups
on exit") causes a regression with grouped events. In particular his
read_group_attached.c test fails.
https://github.com/deater/perf_event_tests/blob/master/tests/bugs/read_group_attached.c
Because of the context switch optimization in
perf_event_context_sched_out() the 'original' event may end up in the
child process and when that exits the change in the patch in question
destroys the actual grouping.
Therefore revert that change and only destroy inherited groups.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-zedy3uktcp753q8fw8dagx7a@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
ring_buffer_poll_wait() should always put the poll_table to its wait_queue
even there is immediate data available. Otherwise, the following epoll and
read sequence will eventually hang forever:
1. Put some data to make the trace_pipe ring_buffer read ready first
2. epoll_ctl(efd, EPOLL_CTL_ADD, trace_pipe_fd, ee)
3. epoll_wait()
4. read(trace_pipe_fd) till EAGAIN
5. Add some more data to the trace_pipe ring_buffer
6. epoll_wait() -> this epoll_wait() will block forever
~ During the epoll_ctl(efd, EPOLL_CTL_ADD,...) call in step 2,
ring_buffer_poll_wait() returns immediately without adding poll_table,
which has poll_table->_qproc pointing to ep_poll_callback(), to its
wait_queue.
~ During the epoll_wait() call in step 3 and step 6,
ring_buffer_poll_wait() cannot add ep_poll_callback() to its wait_queue
because the poll_table->_qproc is NULL and it is how epoll works.
~ When there is new data available in step 6, ring_buffer does not know
it has to call ep_poll_callback() because it is not in its wait queue.
Hence, block forever.
Other poll implementation seems to call poll_wait() unconditionally as the very
first thing to do. For example, tcp_poll() in tcp.c.
Link: http://lkml.kernel.org/p/20140610060637.GA14045@devbig242.prn2.facebook.com
Cc: stable@vger.kernel.org # 2.6.27
Fixes: 2a2cc8f7c4 "ftrace: allow the event pipe to be polled"
Reviewed-by: Chris Mason <clm@fb.com>
Signed-off-by: Martin Lau <kafai@fb.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The TRACE_ITER_PRINTK check in __trace_puts/__trace_bputs is missing,
so add it, to be consistent with __trace_printk/__trace_bprintk.
Those functions are all called by the same function: trace_printk().
Link: http://lkml.kernel.org/p/51E7A7D6.8090900@huawei.com
Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When the create_worker() is called from non-manager, the struct worker
is allocated from the node of the caller which may be different from the
node of pool->node.
So we add a node ID argument for the alloc_worker() to ensure the
struct worker is allocated from the preferable node.
tj: @nid renamed to @node for consistency.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Running my ftrace tests on PowerPC, it failed the test that checks
if function_graph tracer is affected by the stack tracer. It was.
Looking into this, I found that the update_function_graph_func()
must be called even if the trampoline function is not changed.
This is because archs like PowerPC do not support ftrace_ops being
passed by assembly and instead uses a helper function (what the
trampoline function points to). Since this function is not changed
even when multiple ftrace_ops are added to the code, the test that
falls out before calling update_function_graph_func() will miss that
the update must still be done.
Call update_function_graph_function() for all calls to
update_ftrace_function()
Cc: stable@vger.kernel.org # 3.3+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
cgrp_dfl_root_inhibit_ss_mask determines which subsystems are not
supported on the default hierarchy and is currently initialized
statically and just includes the debug subsystem. Now that there's
cgroup_subsys->dfl_files, we can easily tell which subsystems support
the default hierarchy or not.
Let's initialize cgrp_dfl_root_inhibit_ss_mask by testing whether
cgroup_subsys->dfl_files is NULL. After all, subsystems with NULL
->dfl_files aren't useable on the default hierarchy anyway.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup now distinguishes cftypes for the default and legacy
hierarchies more explicitly by using separate arrays and
CFTYPE_ONLY_ON_DFL and CFTYPE_INSANE should be and are used only
inside cgroup core proper. Let's make it clear that the flags are
internal by prefixing them with double underscores.
CFTYPE_INSANE is renamed to __CFTYPE_NOT_ON_DFL for consistency. The
two flags are also collected and assigned bits >= 16 so that they
aren't mixed with the published flags.
v2: Convert the extra ones in cgroup_exit_cftypes() which are added by
revision to the previous patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Until now, cftype arrays carried files for both the default and legacy
hierarchies and the files which needed to be used on only one of them
were flagged with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE. This
gets confusing very quickly and we may end up exposing interface files
to the default hierarchy without thinking it through.
This patch makes cgroup core provide separate sets of interfaces for
cftype handling so that the cftypes for the default and legacy
hierarchies are clearly distinguished. The previous two patches
renamed the existing ones so that they clearly indicate that they're
for the legacy hierarchies. This patch adds the interface for the
default hierarchy and apply them selectively depending on the
hierarchy type.
* cftypes added through cgroup_subsys->dfl_cftypes and
cgroup_add_dfl_cftypes() only show up on the default hierarchy.
* cftypes added through cgroup_subsys->legacy_cftypes and
cgroup_add_legacy_cftypes() only show up on the legacy hierarchies.
* cgroup_subsys->dfl_cftypes and ->legacy_cftypes can point to the
same array for the cases where the interface files are identical on
both types of hierarchies.
* This makes all the existing subsystem interface files legacy-only by
default and all subsystems will have no interface file created when
enabled on the default hierarchy. Each subsystem should explicitly
review and compose the interface for the default hierarchy.
* A boot param "cgroup__DEVEL__legacy_files_on_dfl" is added which
makes subsystems which haven't decided the interface files for the
default hierarchy to present the legacy files on the default
hierarchy so that its behavior on the default hierarchy can be
tested. As the awkward name suggests, this is for development only.
* memcg's CFTYPE_INSANE on "use_hierarchy" is noop now as the whole
array isn't used on the default hierarchy. The flag is removed.
v2: Updated documentation for cgroup__DEVEL__legacy_files_on_dfl.
v3: Clear CFTYPE_ONLY_ON_DFL and CFTYPE_INSANE when cfts are removed
as suggested by Li.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Aristeu Rozanski <aris@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Currently, cftypes added by cgroup_add_cftypes() are used for both the
unified default hierarchy and legacy ones and subsystems can mark each
file with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE if it has to
appear only on one of them. This is quite hairy and error-prone.
Also, we may end up exposing interface files to the default hierarchy
without thinking it through.
cgroup_subsys will grow two separate cftype addition functions and
apply each only on the hierarchies of the matching type. This will
allow organizing cftypes in a lot clearer way and encourage subsystems
to scrutinize the interface which is being exposed in the new default
hierarchy.
In preparation, this patch adds cgroup_add_legacy_cftypes() which
currently is a simple wrapper around cgroup_add_cftypes() and replaces
all cgroup_add_cftypes() usages with it.
While at it, this patch drops a completely spurious return from
__hugetlb_cgroup_file_init().
This patch doesn't introduce any functional differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Currently, cgroup_subsys->base_cftypes is used for both the unified
default hierarchy and legacy ones and subsystems can mark each file
with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE if it has to appear
only on one of them. This is quite hairy and error-prone. Also, we
may end up exposing interface files to the default hierarchy without
thinking it through.
cgroup_subsys will grow two separate cftype arrays and apply each only
on the hierarchies of the matching type. This will allow organizing
cftypes in a lot clearer way and encourage subsystems to scrutinize
the interface which is being exposed in the new default hierarchy.
In preparation, this patch renames cgroup_subsys->base_cftypes to
cgroup_subsys->legacy_cftypes. This patch is pure rename.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Aristeu Rozanski <aris@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Currently cgroup_base_files[] contains the cgroup core interface files
for both legacy and default hierarchies with each file tagged with
CFTYPE_INSANE and CFTYPE_ONLY_ON_DFL. This is difficult to read.
Let's separate it out to two separate tables, cgroup_dfl_base_files[]
and cgroup_legacy_base_files[], and use the appropriate one in
cgroup_mkdir() depending on the hierarchy type. This makes tagging
each file unnecessary.
This patch doesn't introduce any behavior changes.
v2: cgroup_dfl_base_files[] was missing the termination entry
triggering WARN in cgroup_init_cftypes() for 0day kernel testing
robot. Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Jet Chen <jet.chen@intel.com>
Currently trace option stacktrace is not applicable for
trace_printk with constant string argument, the reason is
in __trace_puts/__trace_bputs ftrace_trace_stack is missing.
In contrast, when using trace_printk with non constant string
argument(will call into __trace_printk/__trace_bprintk), then
trace option stacktrace is workable, this inconstant result
will confuses users a lot.
Link: http://lkml.kernel.org/p/51E7A7C9.9040401@huawei.com
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch fixes a NULL pointer dereference issue introduced by
commit 1f0b63866f (ACPI / PM: Hold ACPI scan lock over the "freeze"
sleep state).
Fixes: 1f0b63866f (ACPI / PM: Hold ACPI scan lock over the "freeze" sleep state)
Link: http://marc.info/?l=linux-pm&m=140541182017443&w=2
Reported-and-tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The commit [247bc037: PM / Sleep: Mitigate race between the freezer
and request_firmware()] introduced the finer state control, but it
also leads to a new bug; for example, a bug report regarding the
firmware loading of intel BT device at suspend/resume:
https://bugzilla.novell.com/show_bug.cgi?id=873790
The root cause seems to be a small window between the process resume
and the clear of usermodehelper lock. The request_firmware() function
checks the UMH lock and gives up when it's in UMH_DISABLE state. This
is for avoiding the invalid f/w loading during suspend/resume phase.
The problem is, however, that usermodehelper_enable() is called at the
end of thaw_processes(). Thus, a thawed process in between can kick
off the f/w loader code path (in this case, via btusb_setup_intel())
even before the call of usermodehelper_enable(). Then
usermodehelper_read_trylock() returns an error and request_firmware()
spews WARN_ON() in the end.
This oneliner patch fixes the issue just by setting to UMH_FREEZING
state again before restarting tasks, so that the call of
request_firmware() will be blocked until the end of this function
instead of returning an error.
Fixes: 247bc03742 (PM / Sleep: Mitigate race between the freezer and request_firmware())
Link: https://bugzilla.novell.com/show_bug.cgi?id=873790
Cc: 3.4+ <stable@vger.kernel.org> # 3.4+
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If an IRQ has been configured for wakeup via enable_irq_wake(), the
driver who has done that must be prepared for receiving interrupts
after suspend_device_irqs() has returned, so there is no need to
"suspend" such IRQs. Moreover, if drivers using enable_irq_wake()
actually want to receive interrupts after suspend_device_irqs() has
returned, they need to add IRQF_NO_SUSPEND to the IRQ flags while
requesting the IRQs, which shouldn't be necessary (it also goes a bit
too far, as IRQF_NO_SUSPEND causes the IRQ to be ignored by
suspend_device_irqs() all the time regardless of whether or not it
has been configured for signaling wakeup).
For the above reasons, make __disable_irq() ignore IRQ descriptors
with IRQD_WAKEUP_STATE set when its suspend argument is true which
effectively causes them to behave like IRQs with IRQF_NO_SUSPEND
set.
This also allows IRQs configured for wakeup via enable_irq_wake()
to work as wakeup interrupts for the "freeze" (suspend-to-idle)
sleep mode automatically just like for any other sleep states.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Li Aubrey <aubrey.li@linux.intel.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Link: http://lkml.kernel.org/r/4679574.kGUnqAuNl9@vostro.rjw.lan
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
try_to_grab_pending() was re-calculating the associated pwq using
get_work_pwq() when it already has it cached in a local varible and
the association can't change. Reuse the local variable instead.
This doesn't introduce any functional changes.
tj: Updated description.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull cgroup fixes from Tejun Heo:
"Mostly fixes for the fallouts from the recent cgroup core changes.
The decoupled nature of cgroup dynamic hierarchy management
(hierarchies are created dynamically on mount but may or may not be
reused once unmounted depending on remaining usages) led to more
ugliness being added to kernfs.
Hopefully, this is the last of it"
* 'for-3.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cpuset: break kernfs active protection in cpuset_write_resmask()
cgroup: fix a race between cgroup_mount() and cgroup_kill_sb()
kernfs: introduce kernfs_pin_sb()
cgroup: fix mount failure in a corner case
cpuset,mempolicy: fix sleeping function called from invalid context
cgroup: fix broken css_has_online_children()
Pull workqueue fixes from Tejun Heo:
"Two workqueue fixes. Both are one liners. One fixes missing uevent
for workqueue files on sysfs. The other one fixes missing zeroing of
NUMA cpu masks which can lead to oopses among other things"
* 'for-3.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: zero cpumask of wq_numa_possible_cpumask on init
workqueue: fix dev_set_uevent_suppress() imbalance
cpuset.cpus and cpuset.mems are the configured masks, and we need
to export effective masks to userspace, so users know the real
cpus_allowed and mems_allowed that apply to the tasks in a cpuset.
v2:
- export those masks unconditionally, suggested by Tejun.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
As the configured masks won't be limited by its parent, and the top
cpuset's masks won't change when hotplug happens, it's natural to
allow writing offlined masks to the configured masks.
If on default hierarchy:
# echo 0 > /sys/devices/system/cpu/cpu1/online
# mkdir /cpuset/sub
# echo 1 > /cpuset/sub/cpuset.cpus
# cat /cpuset/sub/cpuset.cpus
1
If on legacy hierarchy:
# echo 0 > /sys/devices/system/cpu/cpu1/online
# mkdir /cpuset/sub
# echo 1 > /cpuset/sub/cpuset.cpus
-bash: echo: write error: Invalid argument
Note the checks don't need to be gated by cgroup_on_dfl, because we've
initialized top_cpuset.{cpus,mems}_allowed accordingly in cpuset_bind().
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Firstly offline cpu1:
# echo 0-1 > cpuset.cpus
# echo 0 > /sys/devices/system/cpu/cpu1/online
# cat cpuset.cpus
0-1
# cat cpuset.effective_cpus
0
Then online it:
# echo 1 > /sys/devices/system/cpu/cpu1/online
# cat cpuset.cpus
0-1
# cat cpuset.effective_cpus
0-1
And cpuset will bring it back to the effective mask.
The implementation is quite straightforward. Instead of calculating the
offlined cpus/mems and do updates, we just set the new effective_mask
to online_mask & congifured_mask.
This is a behavior change for default hierarchy, so legacy hierarchy
won't be affected.
v2:
- make refactoring of cpuset_hotplug_update_tasks() as seperate patch,
suggested by Tejun.
- make hotplug_update_tasks_insane() use @new_cpus and @new_mems as
hotplug_update_tasks_sane() does.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We mix the handling for both default hierarchy and legacy hierarchy in
the same function, and it's quite messy, so split into two functions.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Now we've used effective cpumasks to enforce hierarchical manner,
we can use cs->{cpus,mems}_allowed as configured masks.
Configured masks can be changed by writing cpuset.cpus and cpuset.mems
only. The new behaviors are:
- They won't be changed by hotplug anymore.
- They won't be limited by its parent's masks.
This ia a behavior change, but won't take effect unless mount with
sane_behavior.
v2:
- Add comments to explain the differences between configured masks and
effective masks.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Now we can use cs->effective_{cpus,mems} as effective masks. It's
used whenever:
- we update tasks' cpus_allowed/mems_allowed,
- we want to retrieve tasks_cs(tsk)'s cpus_allowed/mems_allowed.
They actually replace effective_{cpu,node}mask_cpuset().
effective_mask == configured_mask & parent effective_mask except when
the reault is empty, in which case it inherits parent effective_mask.
The result equals the mask computed from effective_{cpu,node}mask_cpuset().
This won't affect the original legacy hierarchy, because in this case we
make sure the effective masks are always the same with user-configured
masks.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We now have to support different behaviors for default hierachy and
legacy hiearchy, top_cpuset's configured masks need to be initialized
accordingly.
Suppose we've offlined cpu1.
On default hierarchy:
# mount -t cgroup -o __DEVEL__sane_behavior xxx /cpuset
# cat /cpuset/cpuset.cpus
0-15
On legacy hierarchy:
# mount -t cgroup xxx /cpuset
# cat /cpuset/cpuset.cpus
0,2-15
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We're going to have separate user-configured masks and effective ones.
Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.
We calculate effective mask this way:
- top cpuset's effective_mask == online_mask, otherwise
- cpuset's effective_mask == configured_mask & parent effective_mask,
if the result is empty, it inherits parent effective mask.
Those behavior changes are for default hierarchy only. For legacy
hierarchy, effective_mask and configured_mask are the same, so we won't
break old interfaces.
We should partition sched domains according to effective_cpus, which
is the real cpulist that takes effects on tasks in the cpuset.
This won't introduce behavior change.
v2:
- Add a comment for the call of rebuild_sched_domains(), suggested
by Tejun.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We're going to have separate user-configured masks and effective ones.
Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.
We calculate effective mask this way:
- top cpuset's effective_mask == online_mask, otherwise
- cpuset's effective_mask == configured_mask & parent effective_mask,
if the result is empty, it inherits parent effective mask.
Those behavior changes are for default hierarchy only. For legacy
hierarchy, effective_mask and configured_mask are the same, so we won't
break old interfaces.
To make cs->effective_{cpus,mems} to be effective masks, we need to
- update the effective masks at hotplug
- update the effective masks at config change
- take on ancestor's mask when the effective mask is empty
The last item is done here.
This won't introduce behavior change.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We're going to have separate user-configured masks and effective ones.
Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.
We calculate effective mask this way:
- top cpuset's effective_mask == online_mask, otherwise
- cpuset's effective_mask == configured_mask & parent effective_mask,
if the result is empty, it inherits parent effective mask.
Those behavior changes are for default hierarchy only. For legacy
hierarchy, effective_mask and configured_mask are the same, so we won't
break old interfaces.
To make cs->effective_{cpus,mems} to be effective masks, we need to
- update the effective masks at hotplug
- update the effective masks at config change
- take on ancestor's mask when the effective mask is empty
The second item is done here. We don't need to treat root_cs specially
in update_cpumasks_hier().
This won't introduce behavior change.
v3:
- add a WARN_ON() to check if effective masks are the same with configured
masks on legacy hierarchy.
- pass trialcs->cpus_allowed to update_cpumasks_hier() and add a comment for
it. Similar change for update_nodemasks_hier(). Suggested by Tejun.
v2:
- revise the comment in update_{cpu,node}masks_hier(), suggested by Tejun.
- fix to use @cp instead of @cs in these two functions.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We're going to have separate user-configured masks and effective ones.
Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.
We calculate effective mask this way:
- top cpuset's effective_mask == online_mask, otherwise
- cpuset's effective_mask == configured_mask & parent effective_mask,
if the result is empty, it inherits parent effective mask.
Those behavior changes are for default hierarchy only. For legacy
hierarchy, effective_mask and configured_mask are the same, so we won't
break old interfaces.
To make cs->effective_{cpus,mems} to be effective masks, we need to
- update the effective masks at hotplug
- update the effective masks at config change
- take on ancestor's mask when the effective mask is empty
The first item is done here.
This won't introduce behavior change.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We're going to have separate user-configured masks and effective ones.
Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.
We calculate effective mask this way:
- top cpuset's effective_mask == online_mask, otherwise
- cpuset's effective_mask == configured_mask & parent effective_mask,
if the result is empty, it inherits parent effective mask.
Those behavior changes are for default hierarchy only. For legacy
hierachy, effective_mask and configured_mask are the same, so we won't
break old interfaces.
This patch adds the effective masks to struct cpuset and initializes
them. The effective masks of the top cpuset is the same with configured
masks, and a child cpuset inherits its parent's effective masks.
This won't introduce behavior change.
v2:
- s/real_{mems,cpus}_allowed/effective_{mems,cpus}, suggested by Tejun.
- don't init effective masks in cpuset_css_online() if !cgroup_on_dfl.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit annotates rcu_report_unblock_qs_rnp() in order to fix the
following sparse warning:
kernel/rcu/tree_plugin.h:990:13: warning: context imbalance in 'rcu_report_unblock_qs_rnp' - unexpected unlock
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
This commit annotates rcu_initiate_boost() fixes the following sparse
warning:
kernel/rcu/tree_plugin.h:1494:13: warning: context imbalance in 'rcu_initiate_boost' - unexpected unlock
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
The __rcu_reclaim() function returned 0/1, which is not proper for a
function of type bool. This commit therefore converts to false/true.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
The CONFIG_PROVE_RCU_DELAY Kconfig parameter doesn't appear to be very
effective at finding race conditions, so this commit removes it.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
[ paulmck: Remove definition and uses as noted by Paul Bolle. ]
Although NMI-based stack dumps are in principle more accurate, they are
also more likely to trigger deadlocks. This commit therefore replaces
all uses of trigger_all_cpu_backtrace() with rcu_dump_cpu_stacks(), so
that the CPU detecting an RCU CPU stall does the stack dumping.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Binding the grace-period kthreads to the timekeeping CPU resulted in
significant performance decreases for some workloads. For more detail,
see:
https://lkml.org/lkml/2014/6/3/395 for benchmark numbers
https://lkml.org/lkml/2014/6/4/218 for CPU statistics
It turns out that it is necessary to bind the grace-period kthreads
to the timekeeping CPU only when all but CPU 0 is a nohz_full CPU
on the one hand or if CONFIG_NO_HZ_FULL_SYSIDLE=y on the other.
In other cases, it suffices to bind the grace-period kthreads to the
set of non-nohz_full CPUs.
This commit therefore creates a tick_nohz_not_full_mask that is the
complement of tick_nohz_full_mask, and then binds the grace-period
kthread to the set of CPUs indicated by this new mask, which covers
the CONFIG_NO_HZ_FULL_SYSIDLE=n case. The CONFIG_NO_HZ_FULL_SYSIDLE=y
case still binds the grace-period kthreads to the timekeeping CPU.
This commit also includes the tick_nohz_full_enabled() check suggested
by Frederic Weisbecker.
Reported-by: Jet Chen <jet.chen@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Created housekeeping_affine() and housekeeping_mask per
fweisbec feedback. ]
RCU priority boosting currently checks for boosting via a pointer in
task_struct. However, this is not needed: As Oleg noted, if the
rt_mutex is placed in the rcu_node instead of on the booster's stack,
the boostee can simply check it see if it owns the lock. This commit
makes this change, shrinking task_struct by one pointer and the kernel
by thirteen lines.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_start_future_gp() function checks the current rcu_node's ->gpnum
and ->completed twice, once without ACCESS_ONCE() and once with it.
Which is pointless because we hold that rcu_node's ->lock at that point.
The intent was to check the current rcu_node structure and the root
rcu_node structure, the latter locklessly with ACCESS_ONCE(). This
commit therefore makes that change.
The reason that it is safe to locklessly check the root rcu_nodes's
->gpnum and ->completed fields is that we hold the current rcu_node's
->lock, which constrains the root rcu_node's ability to change its
->gpnum and ->completed fields. Of course, if there is a single rcu_node
structure, then rnp_root==rnp, and holding the lock prevents all changes.
If there is more than one rcu_node structure, then the code updates the
fields in the following order:
1. Increment rnp_root->gpnum to start new grace period.
2. Increment rnp->gpnum to initialize the current rcu_node,
continuing initialization for the new grace period.
3. Increment rnp_root->completed to end the current grace period.
4. Increment rnp->completed to continue cleaning up after the
old grace period.
So there are four possible combinations of relative values of these
four fields:
N N N N: RCU idle, new grace period must be initiated.
Although rnp_root->gpnum might be incremented immediately
after we check, that will just result in unnecessary work.
The grace period already started, and we try to start it.
N+1 N N N: RCU grace period just started. No further change is
possible because we hold rnp->lock, so the checks of
rnp_root->gpnum and rnp_root->completed are stable.
We know that our request for a future grace period will
be seen during grace-period cleanup.
N+1 N N+1 N: RCU grace period is ongoing. Because rnp->gpnum is
different than rnp->completed, we won't even look at
rnp_root->gpnum and rnp_root->completed, so the possible
concurrent change to rnp_root->completed does not matter.
We know that our request for a future grace period will
be seen during grace-period cleanup, which cannot pass
this rcu_node because we hold its ->lock.
N+1 N+1 N+1 N: RCU grace period has ended, but not yet been cleaned up.
Because rnp->gpnum is different than rnp->completed, we
won't look at rnp_root->gpnum and rnp_root->completed, so
the possible concurrent change to rnp_root->completed does
not matter. We know that our request for a future grace
period will be seen during grace-period cleanup, which
cannot pass this rcu_node because we hold its ->lock.
Therefore, despite initial appearances, the lockless check is safe.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
[ paulmck: Update comment to say why the lockless check is safe. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The current approach to RCU priority boosting uses an rt_mutex strictly
for its priority-boosting side effects. The rt_mutex_init_proxy_locked()
function is used by the booster to initialize the lock as held by the
boostee. The booster then uses rt_mutex_lock() to acquire this rt_mutex,
which priority-boosts the boostee. When the boostee reaches the end
of its outermost RCU read-side critical section, it checks a field in
its task structure to see whether it has been boosted, and, if so, uses
rt_mutex_unlock() to release the rt_mutex. The booster can then go on
to boost the next task that is blocking the current RCU grace period.
But reasonable implementations of rt_mutex_unlock() might result in the
boostee referencing the rt_mutex's data after releasing it. But the
booster might have re-initialized the rt_mutex between the time that the
boostee released it and the time that it later referenced it. This is
clearly asking for trouble, so this commit introduces a completion that
forces the booster to wait until the boostee has completely finished with
the rt_mutex, thus avoiding the case where the booster is re-initializing
the rt_mutex before the last boostee's last reference to that rt_mutex.
This of course does introduce some overhead, but the priority-boosting
code paths are miles from any possible fastpath, and the overhead of
executing the completion will normally be quite small compared to the
overhead of priority boosting and deboosting, so this should be OK.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The m68k architecture aligns only to 16-bit boundaries, which can cause
the align-to-32-bits check in __call_rcu() to trigger. Because there is
currently no known potential need for more than one low-order bit, this
commit loosens the check to 16-bit boundaries.
Reported-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
RCU contains code of the following forms:
ACCESS_ONCE(x)++;
ACCESS_ONCE(x) += y;
ACCESS_ONCE(x) -= y;
Now these constructs do operate correctly, but they really result in a
pair of volatile accesses, one to do the load and another to do the store.
This can be confusing, as the casual reader might well assume that (for
example) gcc might generate a memory-to-memory add instruction for each
of these three cases. In fact, gcc will do no such thing. Also, there
is a good chance that the kernel will move to separate load and store
variants of ACCESS_ONCE(), and constructs like the above could easily
confuse both people and scripts attempting to make that sort of change.
Finally, most of RCU's read-modify-write uses of ACCESS_ONCE() really
only need the store to be volatile, so that the read-modify-write form
might be misleading.
This commit therefore changes the above forms in RCU so that each instance
of ACCESS_ONCE() either does a load or a store, but not both. In a few
cases, ACCESS_ONCE() was not critical, for example, for maintaining
statisitics. In these cases, ACCESS_ONCE() has been dispensed with
entirely.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
In kernels built with CONFIG_NO_HZ_FULL, tick_do_timer_cpu is constant
once boot completes. Thus, there is no need to wrap it in ACCESS_ONCE()
in code that is built only when CONFIG_NO_HZ_FULL. This commit therefore
removes the redundant ACCESS_ONCE().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Those two arrays are being passed to lockdep_init_map(), which expects
const char *, and are stored in lockdep_map the same way.
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The explicit local_irq_save() in __lock_task_sighand() is needed to avoid
a potential deadlock condition, as noted in a841796f11 (signal:
align __lock_task_sighand() irq disabling and RCU). However, someone
reading the code might be forgiven for concluding that this separate
local_irq_save() was completely unnecessary. This commit therefore adds
a comment referencing the shiny new block comment on rcu_read_unlock().
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
After the previous patch to remove sane_behavior support from
non-default hierarchies, CGRP_ROOT_SANE_BEHAVIOR is used only to
indicate the default hierarchy while parsing mount options. This
patch makes the following cleanups around it.
* Don't show it in the mount option. Eventually the default hierarchy
will be assigned a different filesystem type.
* As sane_behavior is no longer effective on non-default hierarchies
and the default hierarchy doesn't accept any mount options,
parse_cgroupfs_options() can consider sane_behavior mount option as
indicating the default hierarchy and fail if any other options are
specified with it. While at it, remove one of the double blank
lines in the function.
* cgroup_mount() can now simply test CGRP_ROOT_SANE_BEHAVIOR to tell
whether to mount the default hierarchy or not.
* As CGROUP_ROOT_SANE_BEHAVIOR's only role now is indicating whether
to select the default hierarchy or not during mount, it doesn't need
to be set in the default hierarchy itself. cgroup_init_early()
updated accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
sane_behavior has been used as a development vehicle for the default
unified hierarchy. Now that the default hierarchy is in place, the
flag became redundant and confusing as its usage is allowed on all
hierarchies. There are gonna be either the default hierarchy or
legacy ones. Let's make that clear by removing sane_behavior support
on non-default hierarchies.
This patch replaces cgroup_sane_behavior() with cgroup_on_dfl(). The
comment on top of CGRP_ROOT_SANE_BEHAVIOR is moved to on top of
cgroup_on_dfl() with sane_behavior specific part dropped.
On the default and legacy hierarchies w/o sane_behavior, this
shouldn't cause any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
"cgroup.sane_behavior" is added to help distinguishing whether
sane_behavior is in effect or not. We now have the default hierarchy
where the flag is always in effect and are planning to remove
supporting sane behavior on the legacy hierarchies making this file on
the default hierarchy rather pointless. Let's make it legacy only and
thus always zero.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup_root->flags only contains CGRP_ROOT_* flags and there's no
reason to mask the flags. Remove CGRP_ROOT_OPTION_MASK.
This doesn't cause any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
idle_exit event is the first event after a core exits
idle state. So this should be traced before local irq
is ebabled. Likewise idle_entry is the last event before
a core enters idle state. This will ease visualising the
cpu idle state from kernel traces.
Signed-off-by: Sandeep Tripathy <sandeep.tripathy@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
[rjw: Subject, rebase]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently, the blkio subsystem attributes all of writeback IOs to the
root. One of the issues is that there's no way to tell who originated
a writeback IO from block layer. Those IOs are usually issued
asynchronously from a task which didn't have anything to do with
actually generating the dirty pages. The memory subsystem, when
enabled, already keeps track of the ownership of each dirty page and
it's desirable for blkio to piggyback instead of adding its own
per-page tag.
blkio piggybacking on memory is an implementation detail which
preferably should be handled automatically without requiring explicit
userland action. To achieve that, this patch implements
cgroup_subsys->depends_on which contains the mask of subsystems which
should be enabled together when the subsystem is enabled.
The previous patches already implemented the support for enabled but
invisible subsystems and cgroup_subsys->depends_on can be easily
implemented by updating cgroup_refresh_child_subsys_mask() so that it
calculates cgroup->child_subsys_mask considering
cgroup_subsys->depends_on of the explicitly enabled subsystems.
Documentation/cgroups/unified-hierarchy.txt is updated to explain that
subsystems may not become immediately available after being unused
from userland and that dependency could be a factor in it. As
subsystems may already keep residual references, this doesn't
significantly change how subsystem rebinding can be used.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
cgroup is implementing support for subsystem dependency which would
require a way to enable a subsystem even when it's not directly
configured through "cgroup.subtree_control".
The previous patches added support for explicitly and implicitly
enabled subsystems and showing/hiding their interface files. An
explicitly enabled subsystem may become implicitly enabled if it's
turned off through "cgroup.subtree_control" but there are subsystems
depending on it. In such cases, the subsystem, as it's turned off
when seen from userland, shouldn't enforce any resource control.
Also, the subsystem may be explicitly turned on later again and its
interface files should be as close to the intial state as possible.
This patch adds cgroup_subsys->css_reset() which is invoked when a css
is hidden. The callback should disable resource control and reset the
state to the vanilla state.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
cgroup is implementing support for subsystem dependency which would
require a way to enable a subsystem even when it's not directly
configured through "cgroup.subtree_control".
The preceding patch distinguished cgroup->subtree_control and
->child_subsys_mask where the former is the subsystems explicitly
configured by the userland and the latter is all enabled subsystems
currently is equal to the former but will include subsystems
implicitly enabled through dependency.
Subsystems which are enabled due to dependency shouldn't be visible to
userland. This patch updates cgroup_subtree_control_write() and
create_css() such that interface files are not created for implicitly
enabled subsytems.
* @visible paramter is added to create_css(). Interface files are
created only when true.
* If an already implicitly enabled subsystem is turned on through
"cgroup.subtree_control", the existing css should be used. css
draining is skipped.
* cgroup_subtree_control_write() computes the new target
cgroup->child_subsys_mask and create/kill or show/hide csses
accordingly.
As the two subsystem masks are still kept identical, this patch
doesn't introduce any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
cgroup is implementing support for subsystem dependency which would
require a way to enable a subsystem even when it's not directly
configured through "cgroup.subtree_control".
Previously, cgroup->child_subsys_mask directly reflected
"cgroup.subtree_control" and the enabled subsystems in the child
cgroups. This patch adds cgroup->subtree_control which
"cgroup.subtree_control" operates on. cgroup->child_subsys_mask is
now calculated from cgroup->subtree_control by
cgroup_refresh_child_subsys_mask(), which sets it identical to
cgroup->subtree_control for now.
This will allow using cgroup->child_subsys_mask for all the enabled
subsystems including the implicit ones and ->subtree_control for
tracking the explicitly requested ones. This patch keeps the two
masks identical and doesn't introduce any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Make the following two reorganizations to
cgroup_subtree_control_write(). These are to prepare for future
changes and shouldn't cause any functional difference.
* Move availability above css offlining wait.
* Move cgrp->child_subsys_mask update above new css creation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Sharvil noticed with the posix timer_settime interface, using the
CLOCK_REALTIME_ALARM or CLOCK_BOOTTIME_ALARM clockid, if the users
tried to specify a relative time timer, it would incorrectly be
treated as absolute regardless of the state of the flags argument.
This patch corrects this, properly checking the absolute/relative flag,
as well as adds further error checking that no invalid flag bits are set.
Reported-by: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Cc: stable <stable@vger.kernel.org> #3.0+
Link: http://lkml.kernel.org/r/1404767171-6902-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Enabling NO_HZ_FULL currently has the side effect of enabling callback
offloading on all CPUs. This results in lots of additional rcuo kthreads,
and can also increase context switching and wakeups, even in cases where
callback offloading is neither needed nor particularly desirable. This
commit therefore enables callback offloading on a given CPU only if
specifically requested at build time or boot time, or if that CPU has
been specifically designated (again, either at build time or boot time)
as a nohz_full CPU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
An 80-CPU system with a context-switch-heavy workload can require so
many NOCB kthread wakeups that the RCU grace-period kthreads spend several
tens of percent of a CPU just awakening things. This clearly will not
scale well: If you add enough CPUs, the RCU grace-period kthreads would
get behind, increasing grace-period latency.
To avoid this problem, this commit divides the NOCB kthreads into leaders
and followers, where the grace-period kthreads awaken the leaders each of
whom in turn awakens its followers. By default, the number of groups of
kthreads is the square root of the number of CPUs, but this default may
be overridden using the rcutree.rcu_nocb_leader_stride boot parameter.
This reduces the number of wakeups done per grace period by the RCU
grace-period kthread by the square root of the number of CPUs, but of
course by shifting those wakeups to the leaders. In addition, because
the leaders do grace periods on behalf of their respective followers,
the number of wakeups of the followers decreases by up to a factor of two.
Instead of being awakened once when new callbacks arrive and again
at the end of the grace period, the followers are awakened only at
the end of the grace period.
For a numerical example, in a 4096-CPU system, the grace-period kthread
would awaken 64 leaders, each of which would awaken its 63 followers
at the end of the grace period. This compares favorably with the 79
wakeups for the grace-period kthread on an 80-CPU system.
Reported-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Since the torture-test thread creation interface does not include
format string arguments, this commit makes sure the name can never be
accidentally processed as a format string.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
When hot-adding and onlining CPU, kernel panic occurs, showing following
call trace.
BUG: unable to handle kernel paging request at 0000000000001d08
IP: [<ffffffff8114acfd>] __alloc_pages_nodemask+0x9d/0xb10
PGD 0
Oops: 0000 [#1] SMP
...
Call Trace:
[<ffffffff812b8745>] ? cpumask_next_and+0x35/0x50
[<ffffffff810a3283>] ? find_busiest_group+0x113/0x8f0
[<ffffffff81193bc9>] ? deactivate_slab+0x349/0x3c0
[<ffffffff811926f1>] new_slab+0x91/0x300
[<ffffffff815de95a>] __slab_alloc+0x2bb/0x482
[<ffffffff8105bc1c>] ? copy_process.part.25+0xfc/0x14c0
[<ffffffff810a3c78>] ? load_balance+0x218/0x890
[<ffffffff8101a679>] ? sched_clock+0x9/0x10
[<ffffffff81105ba9>] ? trace_clock_local+0x9/0x10
[<ffffffff81193d1c>] kmem_cache_alloc_node+0x8c/0x200
[<ffffffff8105bc1c>] copy_process.part.25+0xfc/0x14c0
[<ffffffff81114d0d>] ? trace_buffer_unlock_commit+0x4d/0x60
[<ffffffff81085a80>] ? kthread_create_on_node+0x140/0x140
[<ffffffff8105d0ec>] do_fork+0xbc/0x360
[<ffffffff8105d3b6>] kernel_thread+0x26/0x30
[<ffffffff81086652>] kthreadd+0x2c2/0x300
[<ffffffff81086390>] ? kthread_create_on_cpu+0x60/0x60
[<ffffffff815f20ec>] ret_from_fork+0x7c/0xb0
[<ffffffff81086390>] ? kthread_create_on_cpu+0x60/0x60
In my investigation, I found the root cause is wq_numa_possible_cpumask.
All entries of wq_numa_possible_cpumask is allocated by
alloc_cpumask_var_node(). And these entries are used without initializing.
So these entries have wrong value.
When hot-adding and onlining CPU, wq_update_unbound_numa() is called.
wq_update_unbound_numa() calls alloc_unbound_pwq(). And alloc_unbound_pwq()
calls get_unbound_pool(). In get_unbound_pool(), worker_pool->node is set
as follow:
3592 /* if cpumask is contained inside a NUMA node, we belong to that node */
3593 if (wq_numa_enabled) {
3594 for_each_node(node) {
3595 if (cpumask_subset(pool->attrs->cpumask,
3596 wq_numa_possible_cpumask[node])) {
3597 pool->node = node;
3598 break;
3599 }
3600 }
3601 }
But wq_numa_possible_cpumask[node] does not have correct cpumask. So, wrong
node is selected. As a result, kernel panic occurs.
By this patch, all entries of wq_numa_possible_cpumask are allocated by
zalloc_cpumask_var_node to initialize them. And the panic disappeared.
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
Fixes: bce903809a ("workqueue: add wq_numa_tbl_len and wq_numa_possible_cpumask[]")
