Thomas noticed that a lock marked with lockdep_set_novalidate_class()
will still trigger warnings for IRQ inversions. Cure this by skipping
those when marking irq state.
Reported-and-tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-2dp5vmpsxeraqm42kgww6ge2@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
PMU type id can be allocated dynamically, so perf_event_attr::type check
when copying attribute from userspace to kernel is not valid.
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1309421396-17438-4-git-send-email-ming.m.lin@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
"entity_key()" is only used in "__enqueue_entity()" and
its only function is to subtract a tasks vruntime by
its groups minvruntime.
Before this patch a rbtree enqueue-decision is done by
comparing two tasks in the style:
"if (entity_key(cfs_rq, se) < entity_key(cfs_rq, entry))"
which would be
"if (se->vruntime-cfs_rq->min_vruntime < entry->vruntime-cfs_rq->min_vruntime)"
or (if reducing cfs_rq->min_vruntime out)
"if (se->vruntime < entry->vruntime)"
which is
"if (entity_before(se, entry))"
So we do not need "entity_key()".
If "entity_before()" is inline we will also save one subtraction (only one,
because "entity_key(cfs_rq, se)" was cached in "key")
Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-ns12mnd2h5w8rb9agd8hnsfk@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Clean up cfs/rt runqueue initialization by moving group scheduling
related code into the corresponding functions.
Also, keep group scheduling as an add-on, so that things are only done
additionally, i. e. remove the init_*_rq() calls from init_tg_*_entry().
(This removes a redundant initalization during sched_init()).
In case of group scheduling rt_rq->highest_prio.curr is now initialized
twice, but adding another #ifdef seems not worth it.
Signed-off-by: Jan H. Schönherr <schnhrr@cs.tu-berlin.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1310661163-16606-1-git-send-email-schnhrr@cs.tu-berlin.de
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reorder root_domain to remove 8 bytes of alignment padding on 64 bit
builds, this shrinks the size from 1736 to 1728 bytes, therefore using
one fewer cachelines.
Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1310726492.1977.5.camel@castor.rsk
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If a task group is to be created and alloc_fair_sched_group() fails,
then the rt_bandwidth of the corresponding task group is not yet
initialized. The caller, sched_create_group(), starts a clean up
procedure which calls free_rt_sched_group() which unconditionally
destroys the not yet initialized rt_bandwidth.
This crashes or hangs the system in lock_hrtimer_base(): UP systems
dereference a NULL pointer, while SMP systems loop endlessly on a
condition that cannot become true.
This patch simply avoids the destruction of rt_bandwidth when the
initialization code path was not reached.
(This was discovered by accident with a custom kernel modification.)
Signed-off-by: Bianca Lutz <sowilo@cs.tu-berlin.de>
Signed-off-by: Jan Schoenherr <schnhrr@cs.tu-berlin.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1310580816-10861-7-git-send-email-schnhrr@cs.tu-berlin.de
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The last reference to cpu_cfs_rq() was removed with commit 88ec22d3
("sched: Remove the cfs_rq dependency from set_task_cpu()"). Thus,
remove this function, too.
Signed-off-by: Jan Schoenherr <schnhrr@cs.tu-berlin.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1310580816-10861-3-git-send-email-schnhrr@cs.tu-berlin.de
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Use for_each_leaf_cfs_rq() instead of list_for_each_entry_rcu(), this
achieves that load_balance_fair() only iterates those task_groups that
actually have tasks on busiest, and that we iterate bottom-up, trying to
move light groups before the heavier ones.
No idea if it will actually work out to be beneficial in practice, does
anybody have a cgroup workload that might show a difference one way or
the other?
[ Also move update_h_load to sched_fair.c, loosing #ifdef-ery ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Paul Turner <pjt@google.com>
Link: http://lkml.kernel.org/r/1310557009.2586.28.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In dequeue_task_fair() we bail on dequeue when we encounter a parenting entity
with additional weight. However, we perform a double shares update on this
entity as we continue the shares update traversal from this point, despite
dequeue_entity() having already updated its queuing cfs_rq.
Avoid this by starting from the parent when we resume.
Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110707053059.797714697@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
While looking at check_preempt_wakeup() I realized that we are
potentially updating the wrong entity in the fair-group scheduling
case. In this case the current task's cfs_rq may not be the same as
the one used for the comparison between the waking task and the
existing task's vruntime.
This potentially results in us using a stale vruntime in the
pre-emption decision, providing a small false preference for the
previous task. The effects of this are bounded since we always
perform a hierarchal update on the tick.
Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/CAPM31R+2Ke2urUZKao5W92_LupdR4AYEv-EZWiJ3tG=tEes2cw@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Simple test-case,
int main(void)
{
int pid, status;
pid = fork();
if (!pid) {
pause();
assert(0);
return 0x23;
}
assert(ptrace(PTRACE_ATTACH, pid, 0,0) == 0);
assert(wait(&status) == pid);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP);
kill(pid, SIGCONT); // <--- also clears STOP_DEQUEUD
assert(ptrace(PTRACE_CONT, pid, 0,0) == 0);
assert(wait(&status) == pid);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGCONT);
assert(ptrace(PTRACE_CONT, pid, 0, SIGSTOP) == 0);
assert(wait(&status) == pid);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP);
kill(pid, SIGKILL);
return 0;
}
Without the patch it hangs. After the patch SIGSTOP "injected" by the
tracer is not ignored and stops the tracee.
Note also that if this test-case uses, say, SIGWINCH instead of SIGCONT,
everything works without the patch. This can't be right, and this is
confusing.
The problem is that SIGSTOP (or any other sig_kernel_stop() signal) has
no effect without JOBCTL_STOP_DEQUEUED. This means it is simply ignored
after PTRACE_CONT unless JOBCTL_STOP_DEQUEUED was set "by accident", say
it wasn't cleared after initial SIGSTOP sent by PTRACE_ATTACH.
At first glance we could change ptrace_signal() to add STOP_DEQUEUED
after return from ptrace_stop(), but this is not right in case when the
tracer does not change the reported SIGSTOP and SIGCONT comes in between.
This is even more wrong with PT_SEIZED, SIGCONT adds JOBCTL_TRAP_NOTIFY
which will be "lost" during the TRAP_STOP | TRAP_NOTIFY report.
So lets add STOP_DEQUEUED _before_ we report the signal. It has no effect
unless sig_kernel_stop() == T after the tracer resumes us, and in the
latter case the pending STOP_DEQUEUED means no SIGCONT in between, we
should stop.
Note also that if SIGCONT was sent, PT_SEIZED tracee will correctly
report PTRACE_EVENT_STOP/SIGTRAP and thus the tracer can notice the fact
SIGSTOP was cancelled.
Also, move the current->ptrace check from ptrace_signal() to its caller,
get_signal_to_deliver(), this looks more natural.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Terribly embarassing. Don't know how I committed this, but its
KERN_WARNING not KERN_WARN.
This fixes the following compile error:
kernel/time/timekeeping.c: In function ‘__timekeeping_inject_sleeptime’:
kernel/time/timekeeping.c:608: error: ‘KERN_WARN’ undeclared (first use in this function)
kernel/time/timekeeping.c:608: error: (Each undeclared identifier is reported only once
kernel/time/timekeeping.c:608: error: for each function it appears in.)
kernel/time/timekeeping.c:608: error: expected ‘)’ before string constant
make[2]: *** [kernel/time/timekeeping.o] Error 1
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The RCU callback free_head just calls kfree(), so we can use kfree_rcu()
instead of call_rcu().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The rcu callback __put_tree() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(__put_tree).
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The __lock_task_sighand() function calls rcu_read_lock() with interrupts
and preemption enabled, but later calls rcu_read_unlock() with interrupts
disabled. It is therefore possible that this RCU read-side critical
section will be preempted and later RCU priority boosted, which means that
rcu_read_unlock() will call rt_mutex_unlock() in order to deboost itself, but
with interrupts disabled. This results in lockdep splats, so this commit
nests the RCU read-side critical section within the interrupt-disabled
region of code. This prevents the RCU read-side critical section from
being preempted, and thus prevents the attempt to deboost with interrupts
disabled.
It is quite possible that a better long-term fix is to make rt_mutex_unlock()
disable irqs when acquiring the rt_mutex structure's ->wait_lock.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_read_unlock_special() function relies on in_irq() to exclude
scheduler activity from interrupt level. This fails because exit_irq()
can invoke the scheduler after clearing the preempt_count() bits that
in_irq() uses to determine that it is at interrupt level. This situation
can result in failures as follows:
$task IRQ SoftIRQ
rcu_read_lock()
/* do stuff */
<preempt> |= UNLOCK_BLOCKED
rcu_read_unlock()
--t->rcu_read_lock_nesting
irq_enter();
/* do stuff, don't use RCU */
irq_exit();
sub_preempt_count(IRQ_EXIT_OFFSET);
invoke_softirq()
ttwu();
spin_lock_irq(&pi->lock)
rcu_read_lock();
/* do stuff */
rcu_read_unlock();
rcu_read_unlock_special()
rcu_report_exp_rnp()
ttwu()
spin_lock_irq(&pi->lock) /* deadlock */
rcu_read_unlock_special(t);
Ed can simply trigger this 'easy' because invoke_softirq() immediately
does a ttwu() of ksoftirqd/# instead of doing the in-place softirq stuff
first, but even without that the above happens.
Cure this by also excluding softirqs from the
rcu_read_unlock_special() handler and ensuring the force_irqthreads
ksoftirqd/# wakeup is done from full softirq context.
[ Alternatively, delaying the ->rcu_read_lock_nesting decrement
until after the special handling would make the thing more robust
in the face of interrupts as well. And there is a separate patch
for that. ]
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-and-tested-by: Ed Tomlinson <edt@aei.ca>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Ensure scheduler_ipi() calls irq_{enter,exit} when it does some actual
work. Traditionally we never did any actual work from the resched IPI
and all magic happened in the return from interrupt path.
Now that we do do some work, we need to ensure irq_{enter,exit} are
called so that we don't confuse things.
This affects things like timekeeping, NO_HZ and RCU, basically
everything with a hook in irq_enter/exit.
Explicit examples of things going wrong are:
sched_clock_cpu() -- has a callback when leaving NO_HZ state to take
a new reading from GTOD and TSC. Without this
callback, time is stuck in the past.
RCU -- needs in_irq() to work in order to avoid some nasty deadlocks
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The addition of RCU read-side critical sections within runqueue and
priority-inheritance lock critical sections introduced some deadlock
cycles, for example, involving interrupts from __rcu_read_unlock()
where the interrupt handlers call wake_up(). This situation can cause
the instance of __rcu_read_unlock() invoked from interrupt to do some
of the processing that would otherwise have been carried out by the
task-level instance of __rcu_read_unlock(). When the interrupt-level
instance of __rcu_read_unlock() is called with a scheduler lock held
from interrupt-entry/exit situations where in_irq() returns false,
deadlock can result.
This commit resolves these deadlocks by using negative values of
the per-task ->rcu_read_lock_nesting counter to indicate that an
instance of __rcu_read_unlock() is in flight, which in turn prevents
instances from interrupt handlers from doing any special processing.
This patch is inspired by Steven Rostedt's earlier patch that similarly
made __rcu_read_unlock() guard against interrupt-mediated recursion
(see https://lkml.org/lkml/2011/7/15/326), but this commit refines
Steven's approach to avoid the need for preemption disabling on the
__rcu_read_unlock() fastpath and to also avoid the need for manipulating
a separate per-CPU variable.
This patch avoids need for preempt_disable() by instead using negative
values of the per-task ->rcu_read_lock_nesting counter. Note that nested
rcu_read_lock()/rcu_read_unlock() pairs are still permitted, but they will
never see ->rcu_read_lock_nesting go to zero, and will therefore never
invoke rcu_read_unlock_special(), thus preventing them from seeing the
RCU_READ_UNLOCK_BLOCKED bit should it be set in ->rcu_read_unlock_special.
This patch also adds a check for ->rcu_read_unlock_special being negative
in rcu_check_callbacks(), thus preventing the RCU_READ_UNLOCK_NEED_QS
bit from being set should a scheduling-clock interrupt occur while
__rcu_read_unlock() is exiting from an outermost RCU read-side critical
section.
Of course, __rcu_read_unlock() can be preempted during the time that
->rcu_read_lock_nesting is negative. This could result in the setting
of the RCU_READ_UNLOCK_BLOCKED bit after __rcu_read_unlock() checks it,
and would also result it this task being queued on the corresponding
rcu_node structure's blkd_tasks list. Therefore, some later RCU read-side
critical section would enter rcu_read_unlock_special() to clean up --
which could result in deadlock if that critical section happened to be in
the scheduler where the runqueue or priority-inheritance locks were held.
This situation is dealt with by making rcu_preempt_note_context_switch()
check for negative ->rcu_read_lock_nesting, thus refraining from
queuing the task (and from setting RCU_READ_UNLOCK_BLOCKED) if we are
already exiting from the outermost RCU read-side critical section (in
other words, we really are no longer actually in that RCU read-side
critical section). In addition, rcu_preempt_note_context_switch()
invokes rcu_read_unlock_special() to carry out the cleanup in this case,
which clears out the ->rcu_read_unlock_special bits and dequeues the task
(if necessary), in turn avoiding needless delay of the current RCU grace
period and needless RCU priority boosting.
It is still illegal to call rcu_read_unlock() while holding a scheduler
lock if the prior RCU read-side critical section has ever had either
preemption or irqs enabled. However, the common use case is legal,
namely where then entire RCU read-side critical section executes with
irqs disabled, for example, when the scheduler lock is held across the
entire lifetime of the RCU read-side critical section.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
When creating sched_domains, stop when we've covered the entire
target span instead of continuing to create domains, only to
later find they're redundant and throw them away again.
This avoids single node systems from touching funny NUMA
sched_domain creation code and reduces the risks of the new
SD_OVERLAP code.
Requested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Anton Blanchard <anton@samba.org>
Cc: mahesh@linux.vnet.ibm.com
Cc: benh@kernel.crashing.org
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1311180177.29152.57.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Allow for sched_domain spans that overlap by giving such domains their
own sched_group list instead of sharing the sched_groups amongst
each-other.
This is needed for machines with more than 16 nodes, because
sched_domain_node_span() will generate a node mask from the
16 nearest nodes without regard if these masks have any overlap.
Currently sched_domains have a sched_group that maps to their child
sched_domain span, and since there is no overlap we share the
sched_group between the sched_domains of the various CPUs. If however
there is overlap, we would need to link the sched_group list in
different ways for each cpu, and hence sharing isn't possible.
In order to solve this, allocate private sched_groups for each CPU's
sched_domain but have the sched_groups share a sched_group_power
structure such that we can uniquely track the power.
Reported-and-tested-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-08bxqw9wis3qti9u5inifh3y@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In order to prepare for non-unique sched_groups per domain, we need to
carry the cpu_power elsewhere, so put a level of indirection in.
Reported-and-tested-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-qkho2byuhe4482fuknss40ad@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Given some common flag combinations, particularly -Os, gcc will inline
rcu_read_unlock_special() despite its being in an unlikely() clause.
Use noinline to prohibit this misoptimization.
In addition, move the second barrier() in __rcu_read_unlock() so that
it is not on the common-case code path. This will allow the compiler to
generate better code for the common-case path through __rcu_read_unlock().
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
The RCU_BOOST commits for TREE_PREEMPT_RCU introduced an other-task
write to a new RCU_READ_UNLOCK_BOOSTED bit in the task_struct structure's
->rcu_read_unlock_special field, but, as noted by Steven Rostedt, without
correctly synchronizing all accesses to ->rcu_read_unlock_special.
This could result in bits in ->rcu_read_unlock_special being spuriously
set and cleared due to conflicting accesses, which in turn could result
in deadlocks between the rcu_node structure's ->lock and the scheduler's
rq and pi locks. These deadlocks would result from RCU incorrectly
believing that the just-ended RCU read-side critical section had been
preempted and/or boosted. If that RCU read-side critical section was
executed with either rq or pi locks held, RCU's ensuing (incorrect)
calls to the scheduler would cause the scheduler to attempt to once
again acquire the rq and pi locks, resulting in deadlock. More complex
deadlock cycles are also possible, involving multiple rq and pi locks
as well as locks from multiple rcu_node structures.
This commit fixes synchronization by creating ->rcu_boosted field in
task_struct that is accessed and modified only when holding the ->lock
in the rcu_node structure on which the task is queued (on that rcu_node
structure's ->blkd_tasks list). This results in tasks accessing only
their own current->rcu_read_unlock_special fields, making unsynchronized
access once again legal, and keeping the rcu_read_unlock() fastpath free
of atomic instructions and memory barriers.
The reason that the rcu_read_unlock() fastpath does not need to access
the new current->rcu_boosted field is that this new field cannot
be non-zero unless the RCU_READ_UNLOCK_BLOCKED bit is set in the
current->rcu_read_unlock_special field. Therefore, rcu_read_unlock()
need only test current->rcu_read_unlock_special: if that is zero, then
current->rcu_boosted must also be zero.
This bug does not affect TINY_PREEMPT_RCU because this implementation
of RCU accesses current->rcu_read_unlock_special with irqs disabled,
thus preventing races on the !SMP systems that TINY_PREEMPT_RCU runs on.
Maybe-reported-by: Dave Jones <davej@redhat.com>
Maybe-reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
PREEMPT_RCU read-side critical sections blocking an expedited grace
period invoke rcu_report_exp_rnp(). When the last such critical section
has completed, rcu_report_exp_rnp() invokes the scheduler to wake up the
task that invoked synchronize_rcu_expedited() -- needlessly holding the
root rcu_node structure's lock while doing so, thus needlessly providing
a way for RCU and the scheduler to deadlock.
This commit therefore releases the root rcu_node structure's lock before
calling wake_up().
Reported-by: Ed Tomlinson <edt@aei.ca>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
When IKCONFIG is built-in make oldconfig will cause the kernel to be
relinked even if .config didn't change. This happens because of a
config_data.gz dependency on .config. This patch changes the if_changed
to a filechk so that config_data.h is only rebuilt when the contents
have actually changed.
Signed-off-by: Peter Foley <pefoley2@verizon.net>
Signed-off-by: Michal Marek <mmarek@suse.cz>
This change adds a procfs connector event, which is emitted on every
successful process tracer attach or detach.
If some process connects to other one, kernelspace connector reports
process id and thread group id of both these involved processes. On
disconnection null process id is returned.
Such an event allows to create a simple automated userspace mechanism
to be aware about processes connecting to others, therefore predefined
process policies can be applied to them if needed.
Note, a detach signal is emitted only in case, if a tracer process
explicitly executes PTRACE_DETACH request. In other cases like tracee
or tracer exit detach event from proc connector is not reported.
Signed-off-by: Vladimir Zapolskiy <vzapolskiy@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
If the new child is traced, do_fork() adds the pending SIGSTOP.
It assumes that either it is traced because of auto-attach or the
tracer attached later, in both cases sigaddset/set_thread_flag is
correct even if SIGSTOP is already pending.
Now that we have PTRACE_SEIZE this is no longer right in the latter
case. If the tracer does PTRACE_SEIZE after copy_process() makes the
child visible the queued SIGSTOP is wrong.
We could check PT_SEIZED bit and change ptrace_attach() to set both
PT_PTRACED and PT_SEIZED bits simultaneously but see the next patch,
we need to know whether this child was auto-attached or not anyway.
So this patch simply moves this code to ptrace_init_task(), this
way we can never race with ptrace_attach().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
has_stopped_jobs() naively checks task_is_stopped(group_leader). This
was always wrong even without ptrace, group_leader can be dead. And
given that ptrace can change the state to TRACED this is wrong even
in the single-threaded case.
Change the code to check SIGNAL_STOP_STOPPED and simplify the code,
retval + break/continue doesn't make this trivial code more readable.
We could probably add the usual "|| signal->group_stop_count" check
but I don't think this makes sense, the task can start the group-stop
right after the check anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
* pm-domains: (33 commits)
ARM / shmobile: Return -EBUSY from A4LC power off if A3RV is active
PM / Domains: Take .power_off() error code into account
ARM / shmobile: Use genpd_queue_power_off_work()
ARM / shmobile: Use pm_genpd_poweroff_unused()
PM / Domains: Introduce function to power off all unused PM domains
PM / Domains: Queue up power off work only if it is not pending
PM / Domains: Improve handling of wakeup devices during system suspend
PM / Domains: Do not restore all devices on power off error
PM / Domains: Allow callbacks to execute all runtime PM helpers
PM / Domains: Do not execute device callbacks under locks
PM / Domains: Make failing pm_genpd_prepare() clean up properly
PM / Domains: Set device state to "active" during system resume
ARM: mach-shmobile: sh7372 A3RV requires A4LC
PM / Domains: Export pm_genpd_poweron() in header
ARM: mach-shmobile: sh7372 late pm domain off
ARM: mach-shmobile: Runtime PM late init callback
ARM: mach-shmobile: sh7372 D4 support
ARM: mach-shmobile: sh7372 A4MP support
ARM: mach-shmobile: sh7372: make sure that fsi is peripheral of spu2
ARM: mach-shmobile: sh7372 A3SG support
...
This enables pm_notifier_call_chain() to get the actual error code
in the callback rather than always assume -EINVAL by converting all
PM notifier calls to return encapsulate error code with
notifier_from_errno().
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Some platforms wish to implement their PM core suspend code as
modules. To do so, these functions need to be exported to modules.
[rjw: Replaced EXPORT_SYMBOL with EXPORT_SYMBOL_GPL]
Reported-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
A system or a device may need to control suspend/wakeup events. It may
want to wakeup the system after a predefined amount of time or at a
predefined event decided while entering suspend for polling or delayed
work. Then, it may want to enter suspend again if its predefined wakeup
condition is the only wakeup reason and there is no outstanding events;
thus, it does not wakeup the userspace unnecessary or unnecessary
devices and keeps suspended as long as possible (saving the power).
Enabling a system to wakeup after a specified time can be easily
achieved by using RTC. However, to enter suspend again immediately
without invoking userland and unrelated devices, we need additional
features in the suspend framework.
Such need comes from:
1. Monitoring a critical device status without interrupts that can
wakeup the system. (in-suspend polling)
An example is ambient temperature monitoring that needs to shut down
the system or a specific device function if it is too hot or cold. The
temperature of a specific device may be needed to be monitored as well;
e.g., a charger monitors battery temperature in order to stop charging
if overheated.
2. Execute critical "delayed work" at suspend.
A driver or a system/board may have a delayed work (or any similar
things) that it wants to execute at the requested time.
For example, some chargers want to check the battery voltage some
time (e.g., 30 seconds) after the battery is fully charged and the
charger has stopped. Then, the charger restarts charging if the voltage
has dropped more than a threshold, which is smaller than "restart-charger"
voltage, which is a threshold to restart charging regardless of the
time passed.
This patch allows to add "suspend_again" callback at struct
platform_suspend_ops and let the "suspend_again" callback return true if
the system is required to enter suspend again after the current instance
of wakeup. Device-wise suspend_again implemented at dev_pm_ops or
syscore is not done because: a) suspend_again feature is usually under
platform-wise decision and controls the behavior of the whole platform
and b) There are very limited devices related to the usage cases of
suspend_again; chargers and temperature sensors are mentioned so far.
With suspend_again callback registered at struct platform_suspend_ops
suspend_ops in kernel/power/suspend.c with suspend_set_ops by the
platform, the suspend framework tries to enter suspend again by
looping suspend_enter() if suspend_again has returned true and there has
been no errors in the suspending sequence or pending wakeups (by
pm_wakeup_pending).
Tested at Exynos4-NURI.
[rjw: Fixed up kerneldoc comment for suspend_enter().]
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Since the address of a module-local variable can only be
solved after the target module is loaded, the symbol
fetch-argument should be updated when loading target
module.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/20110627072703.6528.75042.stgit@fedora15
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
To support probing module init functions, kprobe-tracer allows
user to define a probe on non-existed function when it is given
with a module name. This also enables user to set a probe on
a function on a specific module, even if a same name (but different)
function is locally defined in another module.
The module name must be in the front of function name and separated
by a ':'. e.g. btrfs:btrfs_init_sysfs
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/20110627072656.6528.89970.stgit@fedora15
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Return -ENOENT if probe point doesn't exist, but still returns
-EINVAL if both of kprobe->addr and kprobe->symbol_name are
specified or both are not specified.
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20110627072650.6528.67329.stgit@fedora15
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu:
rcu: Prevent RCU callbacks from executing before scheduler initialized
Commit 3fe1698b7f ("sched: Deal with non-atomic min_vruntime reads
on 32bit") forgot to initialize min_vruntime_copy which could lead to
an infinite while loop in task_waking_fair() under some circumstances
(early boot, lucky timing).
[ This bug was also reported by others that blamed it on the RCU
initialization problems ]
Reported-and-tested-by: Bruno Wolff III <bruno@wolff.to>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Enabling function tracer to trace all functions, then load a module and
then disable function tracing will cause ftrace to fail.
This can also happen by enabling function tracing on the command line:
ftrace=function
and during boot up, modules are loaded, then you disable function tracing
with 'echo nop > current_tracer' you will trigger a bug in ftrace that
will shut itself down.
The reason is, the new ftrace code keeps ref counts of all ftrace_ops that
are registered for tracing. When one or more ftrace_ops are registered,
all the records that represent the functions that the ftrace_ops will
trace have a ref count incremented. If this ref count is not zero,
when the code modification runs, that function will be enabled for tracing.
If the ref count is zero, that function will be disabled from tracing.
To make sure the accounting was working, FTRACE_WARN_ON()s were added
to updating of the ref counts.
If the ref count hits its max (> 2^30 ftrace_ops added), or if
the ref count goes below zero, a FTRACE_WARN_ON() is triggered which
disables all modification of code.
Since it is common for ftrace_ops to trace all functions in the kernel,
instead of creating > 20,000 hash items for the ftrace_ops, the hash
count is just set to zero, and it represents that the ftrace_ops is
to trace all functions. This is where the issues arrise.
If you enable function tracing to trace all functions, and then add
a module, the modules function records do not get the ref count updated.
When the function tracer is disabled, all function records ref counts
are subtracted. Since the modules never had their ref counts incremented,
they go below zero and the FTRACE_WARN_ON() is triggered.
The solution to this is rather simple. When modules are loaded, and
their functions are added to the the ftrace pool, look to see if any
ftrace_ops are registered that trace all functions. And for those,
update the ref count for the module function records.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Rename probe_* to trace_probe_* for avoiding namespace
confliction. This also fixes improper names of find_probe_event()
and cleanup_all_probes() to find_trace_probe() and
release_all_trace_probes() respectively.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20110627072636.6528.60374.stgit@fedora15
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Instead of hw_nmi_watchdog_set_attr() weak function
and appropriate x86_pmu::hw_watchdog_set_attr() call
we introduce even alias mechanism which allow us
to drop this routines completely and isolate quirks
of Netburst architecture inside P4 PMU code only.
The main idea remains the same though -- to allow
nmi-watchdog and perf top run simultaneously.
Note the aliasing mechanism applies to generic
PERF_COUNT_HW_CPU_CYCLES event only because arbitrary
event (say passed as RAW initially) might have some
additional bits set inside ESCR register changing
the behaviour of event and we can't guarantee anymore
that alias event will give the same result.
P.S. Thanks a huge to Don and Steven for for testing
and early review.
Acked-by: Don Zickus <dzickus@redhat.com>
Tested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Ingo Molnar <mingo@elte.hu>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Stephane Eranian <eranian@google.com>
CC: Lin Ming <ming.m.lin@intel.com>
CC: Arnaldo Carvalho de Melo <acme@redhat.com>
CC: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20110708201712.GS23657@sun
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently the stack trace per event in ftace is only 8 frames.
This can be quite limiting and sometimes useless. Especially when
the "ignore frames" is wrong and we also use up stack frames for
the event processing itself.
Change this to be dynamic by adding a percpu buffer that we can
write a large stack frame into and then copy into the ring buffer.
For interrupts and NMIs that come in while another event is being
process, will only get to use the 8 frame stack. That should be enough
as the task that it interrupted will have the full stack frame anyway.
Requested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch makes update_rq_clock() aware of steal time.
The mechanism of operation is not different from irq_time,
and follows the same principles. This lives in a CONFIG
option itself, and can be compiled out independently of
the rest of steal time reporting. The effect of disabling it
is that the scheduler will still report steal time (that cannot be
disabled), but won't use this information for cpu power adjustments.
Everytime update_rq_clock_task() is invoked, we query information
about how much time was stolen since last call, and feed it into
sched_rt_avg_update().
Although steal time reporting in account_process_tick() keeps
track of the last time we read the steal clock, in prev_steal_time,
this patch do it independently using another field,
prev_steal_time_rq. This is because otherwise, information about time
accounted in update_process_tick() would never reach us in update_rq_clock().
Signed-off-by: Glauber Costa <glommer@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Eric B Munson <emunson@mgebm.net>
CC: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
CC: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This patch accounts steal time time in account_process_tick.
If one or more tick is considered stolen in the current
accounting cycle, user/system accounting is skipped. Idle is fine,
since the hypervisor does not report steal time if the guest
is halted.
Accounting steal time from the core scheduler give us the
advantage of direct acess to the runqueue data. In a later
opportunity, it can be used to tweak cpu power and make
the scheduler aware of the time it lost.
[avi: <asm/paravirt.h> doesn't exist on many archs]
Signed-off-by: Glauber Costa <glommer@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Eric B Munson <emunson@mgebm.net>
CC: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
CC: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
To implement steal time, we need the hypervisor to pass the guest
information about how much time was spent running other processes
outside the VM, while the vcpu had meaningful work to do - halt
time does not count.
This information is acquired through the run_delay field of
delayacct/schedstats infrastructure, that counts time spent in a
runqueue but not running.
Steal time is a per-cpu information, so the traditional MSR-based
infrastructure is used. A new msr, KVM_MSR_STEAL_TIME, holds the
memory area address containing information about steal time
This patch contains the hypervisor part of the steal time infrasructure,
and can be backported independently of the guest portion.
[avi, yongjie: export delayacct_on, to avoid build failures in some configs]
Signed-off-by: Glauber Costa <glommer@redhat.com>
Tested-by: Eric B Munson <emunson@mgebm.net>
CC: Rik van Riel <riel@redhat.com>
CC: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Yongjie Ren <yongjie.ren@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Archs that do not implement CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST, will
fail the dynamic ftrace selftest.
The function tracer has a quick 'off' variable that will prevent
the call back functions from being called. This variable is called
function_trace_stop. In x86, this is implemented directly in the mcount
assembly, but for other archs, an intermediate function is used called
ftrace_test_stop_func().
In dynamic ftrace, the function pointer variable ftrace_trace_function is
used to update the caller code in the mcount caller. But for archs that
do not have CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST set, it only calls
ftrace_test_stop_func() instead, which in turn calls __ftrace_trace_function.
When more than one ftrace_ops is registered, the function it calls is
ftrace_ops_list_func(), which will iterate over all registered ftrace_ops
and call the callbacks that have their hash matching.
The issue happens when two ftrace_ops are registered for different functions
and one is then unregistered. The __ftrace_trace_function is then pointed
to the remaining ftrace_ops callback function directly. This mean it will
be called for all functions that were registered to trace by both ftrace_ops
that were registered.
This is not an issue for archs with CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST,
because the update of ftrace_trace_function doesn't happen until after all
functions have been updated, and then the mcount caller is updated. But
for those archs that do use the ftrace_test_stop_func(), the update is
immediate.
The dynamic selftest fails because it hits this situation, and the
ftrace_ops that it registers fails to only trace what it was suppose to
and instead traces all other functions.
The solution is to delay the setting of __ftrace_trace_function until
after all the functions have been updated according to the registered
ftrace_ops. Also, function_trace_stop is set during the update to prevent
function tracing from calling code that is caused by the function tracer
itself.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently, if set_ftrace_filter() is called when the ftrace_ops is
active, the function filters will not be updated. They will only be updated
when tracing is disabled and re-enabled.
Update the functions immediately during set_ftrace_filter().
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Whenever the hash of the ftrace_ops is updated, the record counts
must be balance. This requires disabling the records that are set
in the original hash, and then enabling the records that are set
in the updated hash.
Moving the update into ftrace_hash_move() removes the bug where the
hash was updated but the records were not, which results in ftrace
triggering a warning and disabling itself because the ftrace_ops filter
is updated while the ftrace_ops was registered, and then the failure
happens when the ftrace_ops is unregistered.
The current code will not trigger this bug, but new code will.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Under some rare but real combinations of configuration parameters, RCU
callbacks are posted during early boot that use kernel facilities that
are not yet initialized. Therefore, when these callbacks are invoked,
hard hangs and crashes ensue. This commit therefore prevents RCU
callbacks from being invoked until after the scheduler is fully up and
running, as in after multiple tasks have been spawned.
It might well turn out that a better approach is to identify the specific
RCU callbacks that are causing this problem, but that discussion will
wait until such time as someone really needs an RCU callback to be invoked
(as opposed to merely registered) during early boot.
Reported-by: julie Sullivan <kernelmail.jms@gmail.com>
Reported-by: RKK <kulkarni.ravi4@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: julie Sullivan <kernelmail.jms@gmail.com>
Tested-by: RKK <kulkarni.ravi4@gmail.com>
KVM has an ioctl to define which signal mask should be used while running
inside VCPU_RUN. At least for big endian systems, this mask is different
on 32-bit and 64-bit systems (though the size is identical).
Add a compat wrapper that converts the mask to whatever the kernel accepts,
allowing 32-bit kvm user space to set signal masks.
This patch fixes qemu with --enable-io-thread on ppc64 hosts when running
32-bit user land.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
fs_excl is a poor man's priority inheritance for filesystems to hint to
the block layer that an operation is important. It was never clearly
specified, not widely adopted, and will not prevent starvation in many
cases (like across cgroups).
fs_excl was introduced with the time sliced CFQ IO scheduler, to
indicate when a process held FS exclusive resources and thus needed
a boost.
It doesn't cover all file systems, and it was never fully complete.
Lets kill it.
Signed-off-by: Justin TerAvest <teravest@google.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Since ca5ecddf (rcu: define __rcu address space modifier for sparse)
rcu_dereference_check use rcu_read_lock_held as a part of condition
automatically so callers do not have to do that as well.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This was legacy code brought over from the RT tree and
is no longer necessary.
Signed-off-by: Dima Zavin <dima@android.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Daniel Walker <dwalker@codeaurora.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/1310084879-10351-2-git-send-email-dima@android.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When I mounted an NFS directory, it caused several modules to be loaded. At the
time I was running the preemptirqsoff tracer, and it showed the following
output:
# tracer: preemptirqsoff
#
# preemptirqsoff latency trace v1.1.5 on 2.6.33.9-rt30-mrg-test
# --------------------------------------------------------------------
# latency: 1177 us, #4/4, CPU#3 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4)
# -----------------
# | task: modprobe-19370 (uid:0 nice:0 policy:0 rt_prio:0)
# -----------------
# => started at: ftrace_module_notify
# => ended at: ftrace_module_notify
#
#
# _------=> CPU#
# / _-----=> irqs-off
# | / _----=> need-resched
# || / _---=> hardirq/softirq
# ||| / _--=> preempt-depth
# |||| /_--=> lock-depth
# |||||/ delay
# cmd pid |||||| time | caller
# \ / |||||| \ | /
modprobe-19370 3d.... 0us!: ftrace_process_locs <-ftrace_module_notify
modprobe-19370 3d.... 1176us : ftrace_process_locs <-ftrace_module_notify
modprobe-19370 3d.... 1178us : trace_hardirqs_on <-ftrace_module_notify
modprobe-19370 3d.... 1178us : <stack trace>
=> ftrace_process_locs
=> ftrace_module_notify
=> notifier_call_chain
=> __blocking_notifier_call_chain
=> blocking_notifier_call_chain
=> sys_init_module
=> system_call_fastpath
That's over 1ms that interrupts are disabled on a Real-Time kernel!
Looking at the cause (being the ftrace author helped), I found that the
interrupts are disabled before the code modification of mcounts into nops. The
interrupts only need to be disabled on start up around this code, not when
modules are being loaded.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If a function is set to be traced by the set_graph_function, but the
option funcgraph-irqs is zero, and the traced function happens to be
called from a interrupt, it will not be traced.
The point of funcgraph-irqs is to not trace interrupts when we are
preempted by an irq, not to not trace functions we want to trace that
happen to be *in* a irq.
Luckily the current->trace_recursion element is perfect to add a flag
to help us be able to trace functions within an interrupt even when
we are not tracing interrupts that preempt the trace.
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This fixes a regression introduced by e59347a "arm: orion:
Use generic irq chip".
Depending on the device, interrupts acknowledgement is done by setting
or by clearing a dedicated register. Replace irq_gc_ack() with some
{set,clr}_bit variants allows to handle both cases.
Note that this patch affects the following SoCs: Davinci, Samsung and
Orion. Except for this last, the change is minor: irq_gc_ack() is just
renamed into irq_gc_ack_set_bit().
For the Orion SoCs, the edge GPIO interrupts support is currently
broken. irq_gc_ack() try to acknowledge a such interrupt by setting
the corresponding cause register bit. The Orion GPIO device expect the
opposite. To fix this issue, the irq_gc_ack_clr_bit() variant is used.
Tested on Network Space v2.
Reported-by: Joey Oravec <joravec@drewtech.com>
Signed-off-by: Simon Guinot <sguinot@lacie.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The "enable" file for the event system can be removed when a module
is unloaded and the event system only has events from that module.
As the event system nr_events count goes to zero, it may be freed
if its ref_count is also set to zero.
Like the "filter" file, the "enable" file may be opened by a task and
referenced later, after a module has been unloaded and the events for
that event system have been removed.
Although the "filter" file referenced the event system structure,
the "enable" file only references a pointer to the event system
name. Since the name is freed when the event system is removed,
it is possible that an access to the "enable" file may reference
a freed pointer.
Update the "enable" file to use the subsystem_open() routine that
the "filter" file uses, to keep a reference to the event system
structure while the "enable" file is opened.
Cc: <stable@kernel.org>
Reported-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The event system is freed when its nr_events is set to zero. This happens
when a module created an event system and then later the module is
removed. Modules may share systems, so the system is allocated when
it is created and freed when the modules are unloaded and all the
events under the system are removed (nr_events set to zero).
The problem arises when a task opened the "filter" file for the
system. If the module is unloaded and it removed the last event for
that system, the system structure is freed. If the task that opened
the filter file accesses the "filter" file after the system has
been freed, the system will access an invalid pointer.
By adding a ref_count, and using it to keep track of what
is using the event system, we can free it after all users
are finished with the event system.
Cc: <stable@kernel.org>
Reported-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There is a bug in free_unnecessary_pages() that causes it to
attempt to free too many pages in some cases, which triggers the
BUG_ON() in memory_bm_clear_bit() for copy_bm. Namely, if
count_data_pages() is initially greater than alloc_normal, we get
to_free_normal equal to 0 and "save" greater from 0. In that case,
if the sum of "save" and count_highmem_pages() is greater than
alloc_highmem, we subtract a positive number from to_free_normal.
Hence, since to_free_normal was 0 before the subtraction and is
an unsigned int, the result is converted to a huge positive number
that is used as the number of pages to free.
Fix this bug by checking if to_free_normal is actually greater
than or equal to the number we're going to subtract from it.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-and-tested-by: Matthew Garrett <mjg@redhat.com>
Cc: stable@kernel.org
Provides the ability to resize a resource that is already allocated.
This functionality is put in place to support reallocation needs of
pci resources.
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The common clocks management code in drivers/base/power/clock_ops.c
is going to be used during system-wide power transitions as well as
for runtime PM, so it shouldn't depend on CONFIG_PM_RUNTIME.
However, the suspend/resume functions provided by it for
CONFIG_PM_RUNTIME unset, to be used during system-wide power
transitions, should not behave in the same way as their counterparts
defined for CONFIG_PM_RUNTIME set, because in that case the clocks
are managed differently at run time.
The names of the functions still contain the word "runtime" after
this change, but that is going to be modified by a separate patch
later.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Introduce common headers, helper functions and callbacks allowing
platforms to use simple generic power domains for runtime power
management.
Introduce struct generic_pm_domain to be used for representing
power domains that each contain a number of devices and may be
parent domains or subdomains with respect to other power domains.
Among other things, this structure includes callbacks to be
provided by platforms for performing specific tasks related to
power management (i.e. ->stop_device() may disable a device's
clocks, while ->start_device() may enable them, ->power_off() is
supposed to remove power from the entire power domain
and ->power_on() is supposed to restore it).
Introduce functions that can be used as power domain runtime PM
callbacks, pm_genpd_runtime_suspend() and pm_genpd_runtime_resume(),
as well as helper functions for the initialization of a power
domain represented by a struct generic_power_domain object,
adding a device to or removing a device from it and adding or
removing subdomains.
Introduce configuration option CONFIG_PM_GENERIC_DOMAINS to be
selected by the platforms that want to use the new code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Reviewed-by: Kevin Hilman <khilman@ti.com>
KVM needs one-shot samples, since a PMC programmed to -X will fire after X
events and then again after 2^40 events (i.e. variable period).
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1309362157-6596-4-git-send-email-avi@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The perf_event overflow handler does not receive any caller-derived
argument, so many callers need to resort to looking up the perf_event
in their local data structure. This is ugly and doesn't scale if a
single callback services many perf_events.
Fix by adding a context parameter to perf_event_create_kernel_counter()
(and derived hardware breakpoints APIs) and storing it in the perf_event.
The field can be accessed from the callback as event->overflow_handler_context.
All callers are updated.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1309362157-6596-2-git-send-email-avi@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since only samples call perf_output_sample() its much saner (and more
correct) to put the sample logic in there than in the
perf_output_begin()/perf_output_end() pair.
Saves a useless argument, reduces conditionals and shrinks
struct perf_output_handle, win!
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-2crpvsx3cqu67q3zqjbnlpsc@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The nmi parameter indicated if we could do wakeups from the current
context, if not, we would set some state and self-IPI and let the
resulting interrupt do the wakeup.
For the various event classes:
- hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from
the PMI-tail (ARM etc.)
- tracepoint: nmi=0; since tracepoint could be from NMI context.
- software: nmi=[0,1]; some, like the schedule thing cannot
perform wakeups, and hence need 0.
As one can see, there is very little nmi=1 usage, and the down-side of
not using it is that on some platforms some software events can have a
jiffy delay in wakeup (when arch_irq_work_raise isn't implemented).
The up-side however is that we can remove the nmi parameter and save a
bunch of conditionals in fast paths.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Michael Cree <mcree@orcon.net.nz>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Due to restriction and specifics of Netburst PMU we need a separated
event for NMI watchdog. In particular every Netburst event
consumes not just a counter and a config register, but also an
additional ESCR register.
Since ESCR registers are grouped upon counters (i.e. if ESCR is occupied
for some event there is no room for another event to enter until its
released) we need to pick up the "least" used ESCR (or the most available
one) for nmi-watchdog purposes -- so MSR_P4_CRU_ESCR2/3 was chosen.
With this patch nmi-watchdog and perf top should be able to run simultaneously.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Lin Ming <ming.m.lin@intel.com>
CC: Arnaldo Carvalho de Melo <acme@redhat.com>
CC: Frederic Weisbecker <fweisbec@gmail.com>
Tested-and-reviewed-by: Don Zickus <dzickus@redhat.com>
Tested-and-reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110623124918.GC13050@sun
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The event tracing infrastructure exposes two timers which should be updated
each time the value of the counter is updated. Currently, these counters are
only updated when userspace calls read() on the fd associated with an event.
This means that counters which are read via the mmap'd page exclusively never
have their timers updated. This patch adds ensures that the timers are updated
each time the values in the mmap'd page are updated.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1308932786-5111-1-git-send-email-emunson@mgebm.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Take the timer calculation from perf_output_read and move it to a helper
function for any place that needs timer values but cannot take the ctx->lock.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1308861279-15216-2-git-send-email-emunson@mgebm.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since 2.6.36 (specifically commit d57e34fdd6 ("perf: Simplify the
ring-buffer logic: make perf_buffer_alloc() do everything needed"),
the perf_buffer_init_code() has been mis-setting the buffer watermark
if perf_event_attr.wakeup_events has a non-zero value.
This is because perf_event_attr.wakeup_events is a union with
perf_event_attr.wakeup_watermark.
This commit re-enables the check for perf_event_attr.watermark being
set before continuing with setting a non-default watermark.
This bug is most noticable when you are trying to use PERF_IOC_REFRESH
with a value larger than one and perf_event_attr.wakeup_events is set to
one. In this case the buffer watermark will be set to 1 and you will
get extraneous POLL_IN overflows rather than POLL_HUP as expected.
[ avoid using attr.wakeup_events when attr.watermark is set ]
Signed-off-by: Vince Weaver <vweaver1@eecs.utk.edu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.00.1106011506390.5384@cl320.eecs.utk.edu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since commit ec514c48 ("sched: Fix rt_rq runtime leakage bug")
'cat /proc/sched_debug' will print data of root_task_group.rt_rq
multiple times.
This is because autogroup does not have its own rt group, instead
rt group of autogroup is linked to root_task_group.
So skip it when we are looking for all rt sched groups, and it
will also save some noop operation against root_task_group when
__disable_runtime()/__enable_runtime().
-v2: Based on Cheng Xu's idea which uses less code.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Cheng Xu <chengxu@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/BANLkTi=87P3RoTF_UEtamNfc_XGxQXE__Q@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It does not make sense to rcu_read_lock/unlock() in every loop
iteration while spinning on the mutex.
Move the rcu protection outside the loop. Also simplify the
return path to always check for lock->owner == NULL which
meets the requirements of both owner changed and need_resched()
caused loop exits.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1106101458350.11814@ionos
Signed-off-by: Ingo Molnar <mingo@elte.hu>
wake_affine() is only called from one path: select_task_rq_fair(),
which already has the RCU read lock held.
Signed-off-by: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20110607101251.777.34547.stgit@IBM-009124035060.in.ibm.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit c8b28116 ("sched: Increase SCHED_LOAD_SCALE resolution")
intended to have no user-visible effect, but allows setting
cpu.shares to < MIN_SHARES, which the user then sees.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nikhil Rao <ncrao@google.com>
Link: http://lkml.kernel.org/r/1307192600.8618.3.camel@marge.simson.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In this revision the conversion of secid to SELinux context and adding it
to the audit log is moved from xt_AUDIT.c to audit.c with the aid of a
separate helper function - audit_log_secctx - which does both the conversion
and logging of SELinux context, thus also preventing internal secid number
being leaked to userspace. If conversion is not successful an error is raised.
With the introduction of this helper function the work done in xt_AUDIT.c is
much more simplified. It also opens the possibility of this helper function
being used by other modules (including auditd itself), if desired. With this
addition, typical (raw auditd) output after applying the patch would be:
type=NETFILTER_PKT msg=audit(1305852240.082:31012): action=0 hook=1 len=52 inif=? outif=eth0 saddr=10.1.1.7 daddr=10.1.2.1 ipid=16312 proto=6 sport=56150 dport=22 obj=system_u:object_r:ssh_client_packet_t:s0
type=NETFILTER_PKT msg=audit(1306772064.079:56): action=0 hook=3 len=48 inif=eth0 outif=? smac=00:05:5d:7c:27:0b dmac=00:02:b3:0a:7f:81 macproto=0x0800 saddr=10.1.2.1 daddr=10.1.1.7 ipid=462 proto=6 sport=22 dport=3561 obj=system_u:object_r:ssh_server_packet_t:s0
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Mr Dash Four <mr.dash.four@googlemail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
The jump labels entries for modules do not stop at __stop__jump_table,
but after mod->jump_entries + mod_num_jump_entries.
By checking the wrong end point, module trace events never get enabled.
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Jason Baron <jbaron@redhat.com>
Tested-by: Avi Kivity <avi@redhat.com>
Tested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/4E00038B.2060404@cn.fujitsu.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently a single process may register exit handlers unlimited times.
It may lead to a bloated listeners chain and very slow process
terminations.
Eg after 10KK sent TASKSTATS_CMD_ATTR_REGISTER_CPUMASKs ~300 Mb of
kernel memory is stolen for the handlers chain and "time id" shows 2-7
seconds instead of normal 0.003. It makes it possible to exhaust all
kernel memory and to eat much of CPU time by triggerring numerous exits
on a single CPU.
The patch limits the number of times a single process may register
itself on a single CPU to one.
One little issue is kept unfixed - as taskstats_exit() is called before
exit_files() in do_exit(), the orphaned listener entry (if it was not
explicitly deregistered) is kept until the next someone's exit() and
implicit deregistration in send_cpu_listeners(). So, if a process
registered itself as a listener exits and the next spawned process gets
the same pid, it would inherit taskstats attributes.
Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MTRR rendezvous sequence is not implemened using stop_machine() before, as this
gets called both from the process context aswell as the cpu online paths
(where the cpu has not come online and the interrupts are disabled etc).
Now that we have a new stop_machine_from_inactive_cpu() API, use it for
rendezvous during mtrr init of a logical processor that is coming online.
For the rest (runtime MTRR modification, system boot, resume paths), use
stop_machine() to implement the rendezvous sequence. This will consolidate and
cleanup the code.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/20110623182057.076997177@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Currently, mtrr wants stop_machine functionality while a CPU is being
brought up. As stop_machine() requires the calling CPU to be active,
mtrr implements its own stop_machine using stop_one_cpu() on each
online CPU. This doesn't only unnecessarily duplicate complex logic
but also introduces a possibility of deadlock when it races against
the generic stop_machine().
This patch implements stop_machine_from_inactive_cpu() to serve such
use cases. Its functionality is basically the same as stop_machine();
however, it should be called from a CPU which isn't active and doesn't
depend on working scheduling on the calling CPU.
This is achieved by using busy loops for synchronization and
open-coding stop_cpus queuing and waiting with direct invocation of
fn() for local CPU inbetween.
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20110623182056.982526827@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Refactor the queuing part of the stop cpus work from __stop_cpus() into
queue_stop_cpus_work().
The reorganization is to help future improvements to stop_machine()
and doesn't introduce any behavior difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20110623182056.897818337@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
MTRR rendezvous sequence using stop_one_cpu_nowait() can potentially
happen in parallel with another system wide rendezvous using
stop_machine(). This can lead to deadlock (The order in which
works are queued can be different on different cpu's. Some cpu's
will be running the first rendezvous handler and others will be running
the second rendezvous handler. Each set waiting for the other set to join
for the system wide rendezvous, leading to a deadlock).
MTRR rendezvous sequence is not implemented using stop_machine() as this
gets called both from the process context aswell as the cpu online paths
(where the cpu has not come online and the interrupts are disabled etc).
stop_machine() works with only online cpus.
For now, take the stop_machine mutex in the MTRR rendezvous sequence that
gets called from an online cpu (here we are in the process context
and can potentially sleep while taking the mutex). And the MTRR rendezvous
that gets triggered during cpu online doesn't need to take this stop_machine
lock (as the stop_machine() already ensures that there is no cpu hotplug
going on in parallel by doing get_online_cpus())
TBD: Pursue a cleaner solution of extending the stop_machine()
infrastructure to handle the case where the calling cpu is
still not online and use this for MTRR rendezvous sequence.
fixes: https://bugzilla.novell.com/show_bug.cgi?id=672008
Reported-by: Vadim Kotelnikov <vadimuzzz@inbox.ru>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/20110623182056.807230326@sbsiddha-MOBL3.sc.intel.com
Cc: stable@kernel.org # 2.6.35+, backport a week or two after this gets more testing in mainline
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
wait_consider_task() checks same_thread_group(parent, real_parent),
this is the open-coded ptrace_reparented().
__ptrace_detach() remains the only function which has to check this by
hand, although we could reorganize the code to delay __ptrace_unlink.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Kill real_parent_is_ptracer() and update the callers to use
ptrace_reparented(), after the previous patch they do the same.
Remove the unnecessary ->ptrace != 0 check in get_signal_to_deliver(),
if ptrace_reparented() == T then the task must be ptraced.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
__ptrace_detach() and do_notify_parent() set task->exit_signal = -1
to mark the task dead. This is no longer needed, nobody checks
exit_signal to detect the EXIT_DEAD task.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Upadate the last user of task_detached(), wait_task_zombie(), to
use thread_group_leader() and kill task_detached().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Change reparent_leader() to check ->exit_state instead of ->exit_signal,
this matches the similar EXIT_DEAD check in wait_consider_task() and
allows us to cleanup the do_notify_parent/task_detached logic.
task_detached() was really needed during reparenting before 9cd80bbb
"do_wait() optimization: do not place sub-threads on ->children list"
to filter out the sub-threads. After this change task_detached(p) can
only be true if p is the dead group_leader and its parent ignores
SIGCHLD, in this case the caller of do_notify_parent() is going to
reap this task and it should set EXIT_DEAD.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Change other callers of do_notify_parent() to check the value it
returns, this makes the subsequent task_detached() unnecessary.
Mark do_notify_parent() as __must_check.
Use thread_group_leader() instead of !task_detached() to check
if we need to notify the real parent in wait_task_zombie().
Remove the stale comment in release_task(). "just for sanity" is
no longer true, we have to set EXIT_DEAD to avoid the races with
do_wait().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
__ptrace_detach() relies on the current obscure behaviour of
do_notify_parent(tsk) which changes tsk->exit_signal if this child
should be silently reaped. That is why we check task_detached(), it
is true if the task is sub-thread, or it is the group_leader but
its exit_signal was changed by do_notify_parent().
This is confusing, change the code to rely on !thread_group_leader()
or the value returned by do_notify_parent().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Kill tracehook_notify_death(), reimplement the logic in its caller,
exit_notify().
Also, change the exec_id's check to use thread_group_leader() instead
of task_detached(), this is more clear. This logic only applies to
the exiting leader, a sub-thread must never change its exit_signal.
Note: when the traced group leader exits the exit_signal-or-SIGCHLD
logic looks really strange:
- we notify the tracer even if !thread_group_empty() but
do_wait(WEXITED) can't work until all threads exit
- if the tracer is real_parent, it is not clear why can't
we use ->exit_signal event if !thread_group_empty()
-v2: do not try to fix the 2nd oddity to avoid the subtle behavior
change mixed with reorganization, suggested by Tejun.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
- change do_notify_parent() to return a boolean, true if the task should
be reaped because its parent ignores SIGCHLD.
- update the only caller which checks the returned value, exit_notify().
This temporary uglifies exit_notify() even more, will be cleanuped by
the next change.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
The sleeping inside spinlock detection is actually used
for more general sleeping inside atomic sections
debugging: preemption disabled, rcu read side critical
sections, interrupts, interrupt disabled, etc...
Change the name of the config and its help section to
reflect its more general role.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
At this point, tracehooks aren't useful to mainline kernel and mostly
just add an extra layer of obfuscation. Although they have comments,
without actual in-kernel users, it is difficult to tell what are their
assumptions and they're actually trying to achieve. To mainline
kernel, they just aren't worth keeping around.
This patch kills the following clone and exec related tracehooks.
tracehook_prepare_clone()
tracehook_finish_clone()
tracehook_report_clone()
tracehook_report_clone_complete()
tracehook_unsafe_exec()
The changes are mostly trivial - logic is moved to the caller and
comments are merged and adjusted appropriately.
The only exception is in check_unsafe_exec() where LSM_UNSAFE_PTRACE*
are OR'd to bprm->unsafe instead of setting it, which produces the
same result as the field is always zero on entry. It also tests
p->ptrace instead of (p->ptrace & PT_PTRACED) for consistency, which
also gives the same result.
This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
At this point, tracehooks aren't useful to mainline kernel and mostly
just add an extra layer of obfuscation. Although they have comments,
without actual in-kernel users, it is difficult to tell what are their
assumptions and they're actually trying to achieve. To mainline
kernel, they just aren't worth keeping around.
This patch kills the following trivial tracehooks.
* Ones testing whether task is ptraced. Replace with ->ptrace test.
tracehook_expect_breakpoints()
tracehook_consider_ignored_signal()
tracehook_consider_fatal_signal()
* ptrace_event() wrappers. Call directly.
tracehook_report_exec()
tracehook_report_exit()
tracehook_report_vfork_done()
* ptrace_release_task() wrapper. Call directly.
tracehook_finish_release_task()
* noop
tracehook_prepare_release_task()
tracehook_report_death()
This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
task_ptrace(task) simply dereferences task->ptrace and isn't even used
consistently only adding confusion. Kill it and directly access
->ptrace instead.
This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Commit:
1efc5da3cf: [PATCH] order of lockdep off/on in vprintk() should be changed
explains the reason for having raw_local_irq_*() and lockdep_off()
in printk(). Instead of working around the broken recursion detection
of interrupt state tracking, fix it.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: efault@gmx.de
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110621153806.185242734@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix up the fallout from commit 0b5e1c5255 ("printk: Release
console_sem after logbuf_lock").
The reason for unlocking the console_sem under the logbuf_lock
is that a concurrent printk() might fill up the buffer but fail
to acquire the console sem, resulting in a missed write to the
console until a subsequent console_sem acquire/release cycle.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: efault@gmx.de
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1308734409.1022.14.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Because the read_persistent_clock interface is usually backed by
only a second granular interface, each time we read from the persistent
clock for suspend/resume, we introduce a half second (on average) of error.
In order to avoid this error accumulating as the system is suspended
over and over, this patch measures the time delta between the persistent
clock and the system CLOCK_REALTIME.
If the delta is less then 2 seconds from the last suspend, we compensate
by using the previous time delta (keeping it close). If it is larger
then 2 seconds, we assume the clock was set or has been changed, so we
do no correction and update the delta.
Note: If NTP is running, ths could seem to "fight" with the NTP corrected
time, where as if the system time was off by 1 second, and NTP slewed the
value in, a suspend/resume cycle could undo this correction, by trying to
restore the previous offset from the persistent clock. However, without
this patch, since each read could cause almost a full second worth of
error, its possible to get almost 2 seconds of error just from the
suspend/resume cycle alone, so this about equal to any offset added by
the compensation.
Further on systems that suspend/resume frequently, this should keep time
closer then NTP could compensate for if the errors were allowed to
accumulate.
Credits to Arve Hjønnevåg for suggesting this solution.
CC: Arve Hjønnevåg <arve@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Arve suggested making sure we catch possible negative sleep time
intervals that could be passed into timekeeping_inject_sleeptime.
CC: Arve Hjønnevåg <arve@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Toralf Förster and Richard Weinberger noted that if there is
no RTC device, the alarm timers core prints out an annoying
"ALARM timers will not wake from suspend" message.
This warning has been removed in a previous patch, however
the issue still remains: The original idea was to support
alarm timers even if there was no rtc device, as long as the
system didn't go into suspend.
However, after further consideration, communicating to the application
that alarmtimers are not fully functional seems like the better
solution.
So this patch makes it so we return -ENOTSUPP to any posix _ALARM
clockid calls if there is no backing RTC device on the system.
Further this changes the behavior where when there is no rtc device
we will check for one on clock_getres, clock_gettime, timer_create,
and timer_nsleep instead of on suspend.
CC: Toralf Förster <toralf.foerster@gmx.de>
CC: Richard Weinberger <richard@nod.at
CC: Peter Zijlstra <peterz@infradead.org>
CC: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Reported by: Richard Weinberger <richard@nod.at>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The alarmtimers code currently picks a rtc device to use at
late init time. However, if your rtc driver is loaded as a module,
it may be registered after the alarmtimers late init code, leaving
the alarmtimers nonfunctional.
This patch moves the the rtcdevice selection to when we actually try
to use it, allowing us to make use of rtc modules that may have been
loaded at any point since bootup.
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Meelis Roos <mroos@ut.ee>
Reported-by: Meelis Roos <mroos@ut.ee>
Signed-off-by: John Stultz <john.stultz@linaro.org>
When opening /dev/snapshot device, snapshot_open() creates memory
bitmaps which are freed in snapshot_release(). But if any of the
callbacks called by pm_notifier_call_chain() returns NOTIFY_BAD, open()
fails, snapshot_release() is never called and bitmaps are not freed.
Next attempt to open /dev/snapshot then triggers BUG_ON() check in
create_basic_memory_bitmaps(). This happens e.g. when vmwatchdog module
is active on s390x.
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
tools/perf: Fix static build of perf tool
tracing: Fix regression in printk_formats file
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
generic-ipi: Fix kexec boot crash by initializing call_single_queue before enabling interrupts
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
clocksource: Make watchdog robust vs. interruption
timerfd: Fix wakeup of processes when timer is cancelled on clock change
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, MAINTAINERS: Add x86 MCE people
x86, efi: Do not reserve boot services regions within reserved areas
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: Move RCU_BOOST #ifdefs to header file
rcu: use softirq instead of kthreads except when RCU_BOOST=y
rcu: Use softirq to address performance regression
rcu: Simplify curing of load woes
____call_usermodehelper() now erases any credentials set by the
subprocess_inf::init() function. The problem is that commit
17f60a7da1 ("capabilites: allow the application of capability limits
to usermode helpers") creates and commits new credentials with
prepare_kernel_cred() after the call to the init() function. This wipes
all keyrings after umh_keys_init() is called.
The best way to deal with this is to put the init() call just prior to
the commit_creds() call, and pass the cred pointer to init(). That
means that umh_keys_init() and suchlike can modify the credentials
_before_ they are published and potentially in use by the rest of the
system.
This prevents request_key() from working as it is prevented from passing
the session keyring it set up with the authorisation token to
/sbin/request-key, and so the latter can't assume the authority to
instantiate the key. This causes the in-kernel DNS resolver to fail
with ENOKEY unconditionally.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Tested-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is a problem that kdump(2nd kernel) sometimes hangs up due
to a pending IPI from 1st kernel. Kernel panic occurs because IPI
comes before call_single_queue is initialized.
To fix the crash, rename init_call_single_data() to call_function_init()
and call it in start_kernel() so that call_single_queue can be
initialized before enabling interrupts.
The details of the crash are:
(1) 2nd kernel boots up
(2) A pending IPI from 1st kernel comes when irqs are first enabled
in start_kernel().
(3) Kernel tries to handle the interrupt, but call_single_queue
is not initialized yet at this point. As a result, in the
generic_smp_call_function_single_interrupt(), NULL pointer
dereference occurs when list_replace_init() tries to access
&q->list.next.
Therefore this patch changes the name of init_call_single_data()
to call_function_init() and calls it before local_irq_enable()
in start_kernel().
Signed-off-by: Takao Indoh <indou.takao@jp.fujitsu.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Milton Miller <miltonm@bga.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: kexec@lists.infradead.org
Link: http://lkml.kernel.org/r/D6CBEE2F420741indou.takao@jp.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The commit "use softirq instead of kthreads except when RCU_BOOST=y"
just applied #ifdef in place. This commit is a cleanup that moves
the newly #ifdef'ed code to the header file kernel/rcutree_plugin.h.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The previous patch implemented async notification for ptrace but it
only worked while trace is running. This patch introduces
PTRACE_LISTEN which is suggested by Oleg Nestrov.
It's allowed iff tracee is in STOP trap and puts tracee into
quasi-running state - tracee never really runs but wait(2) and
ptrace(2) consider it to be running. While ptracer is listening,
tracee is allowed to re-enter STOP to notify an async event.
Listening state is cleared on the first notification. Ptracer can
also clear it by issuing INTERRUPT - tracee will re-trap into STOP
with listening state cleared.
This allows ptracer to monitor group stop state without running tracee
- use INTERRUPT to put tracee into STOP trap, issue LISTEN and then
wait(2) to wait for the next group stop event. When it happens,
PTRACE_GETSIGINFO provides information to determine the current state.
Test program follows.
#define PTRACE_SEIZE 0x4206
#define PTRACE_INTERRUPT 0x4207
#define PTRACE_LISTEN 0x4208
#define PTRACE_SEIZE_DEVEL 0x80000000
static const struct timespec ts1s = { .tv_sec = 1 };
int main(int argc, char **argv)
{
pid_t tracee, tracer;
int i;
tracee = fork();
if (!tracee)
while (1)
pause();
tracer = fork();
if (!tracer) {
siginfo_t si;
ptrace(PTRACE_SEIZE, tracee, NULL,
(void *)(unsigned long)PTRACE_SEIZE_DEVEL);
ptrace(PTRACE_INTERRUPT, tracee, NULL, NULL);
repeat:
waitid(P_PID, tracee, NULL, WSTOPPED);
ptrace(PTRACE_GETSIGINFO, tracee, NULL, &si);
if (!si.si_code) {
printf("tracer: SIG %d\n", si.si_signo);
ptrace(PTRACE_CONT, tracee, NULL,
(void *)(unsigned long)si.si_signo);
goto repeat;
}
printf("tracer: stopped=%d signo=%d\n",
si.si_signo != SIGTRAP, si.si_signo);
if (si.si_signo != SIGTRAP)
ptrace(PTRACE_LISTEN, tracee, NULL, NULL);
else
ptrace(PTRACE_CONT, tracee, NULL, NULL);
goto repeat;
}
for (i = 0; i < 3; i++) {
nanosleep(&ts1s, NULL);
printf("mother: SIGSTOP\n");
kill(tracee, SIGSTOP);
nanosleep(&ts1s, NULL);
printf("mother: SIGCONT\n");
kill(tracee, SIGCONT);
}
nanosleep(&ts1s, NULL);
kill(tracer, SIGKILL);
kill(tracee, SIGKILL);
return 0;
}
This is identical to the program to test TRAP_NOTIFY except that
tracee is PTRACE_LISTEN'd instead of PTRACE_CONT'd when group stopped.
This allows ptracer to monitor when group stop ends without running
tracee.
# ./test-listen
tracer: stopped=0 signo=5
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
-v2: Moved JOBCTL_LISTENING check in wait_task_stopped() into
task_stopped_code() as suggested by Oleg.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Currently there's no way for ptracer to find out whether group stop
finished other than polling with INTERRUPT - GETSIGINFO - CONT
sequence. This patch implements group stop notification for ptracer
using STOP traps.
When group stop state of a seized tracee changes, JOBCTL_TRAP_NOTIFY
is set, which schedules a STOP trap which is sticky - it isn't cleared
by other traps and at least one STOP trap will happen eventually.
STOP trap is synchronization point for event notification and the
tracer can determine the current group stop state by looking at the
signal number portion of exit code (si_status from waitid(2) or
si_code from PTRACE_GETSIGINFO).
Notifications are generated both on start and end of group stops but,
because group stop participation always happens before STOP trap, this
doesn't cause an extra trap while tracee is participating in group
stop. The symmetry will be useful later.
Note that this notification works iff tracee is not trapped.
Currently there is no way to be notified of group stop state changes
while tracee is trapped. This will be addressed by a later patch.
An example program follows.
#define PTRACE_SEIZE 0x4206
#define PTRACE_INTERRUPT 0x4207
#define PTRACE_SEIZE_DEVEL 0x80000000
static const struct timespec ts1s = { .tv_sec = 1 };
int main(int argc, char **argv)
{
pid_t tracee, tracer;
int i;
tracee = fork();
if (!tracee)
while (1)
pause();
tracer = fork();
if (!tracer) {
siginfo_t si;
ptrace(PTRACE_SEIZE, tracee, NULL,
(void *)(unsigned long)PTRACE_SEIZE_DEVEL);
ptrace(PTRACE_INTERRUPT, tracee, NULL, NULL);
repeat:
waitid(P_PID, tracee, NULL, WSTOPPED);
ptrace(PTRACE_GETSIGINFO, tracee, NULL, &si);
if (!si.si_code) {
printf("tracer: SIG %d\n", si.si_signo);
ptrace(PTRACE_CONT, tracee, NULL,
(void *)(unsigned long)si.si_signo);
goto repeat;
}
printf("tracer: stopped=%d signo=%d\n",
si.si_signo != SIGTRAP, si.si_signo);
ptrace(PTRACE_CONT, tracee, NULL, NULL);
goto repeat;
}
for (i = 0; i < 3; i++) {
nanosleep(&ts1s, NULL);
printf("mother: SIGSTOP\n");
kill(tracee, SIGSTOP);
nanosleep(&ts1s, NULL);
printf("mother: SIGCONT\n");
kill(tracee, SIGCONT);
}
nanosleep(&ts1s, NULL);
kill(tracer, SIGKILL);
kill(tracee, SIGKILL);
return 0;
}
In the above program, tracer keeps tracee running and gets
notification of each group stop state changes.
# ./test-notify
tracer: stopped=0 signo=5
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
mother: SIGSTOP
tracer: SIG 19
tracer: stopped=1 signo=19
mother: SIGCONT
tracer: stopped=0 signo=5
tracer: SIG 18
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Currently, there's no way to trap a running ptracee short of sending a
signal which has various side effects. This patch implements
PTRACE_INTERRUPT which traps ptracee without any signal or job control
related side effect.
The implementation is almost trivial. It uses the group stop trap -
SIGTRAP | PTRACE_EVENT_STOP << 8. A new trap flag
JOBCTL_TRAP_INTERRUPT is added, which is set on PTRACE_INTERRUPT and
cleared when any trap happens. As INTERRUPT should be useable
regardless of the current state of tracee, task_is_traced() test in
ptrace_check_attach() is skipped for INTERRUPT.
PTRACE_INTERRUPT is available iff tracee is attached with
PTRACE_SEIZE.
Test program follows.
#define PTRACE_SEIZE 0x4206
#define PTRACE_INTERRUPT 0x4207
#define PTRACE_SEIZE_DEVEL 0x80000000
static const struct timespec ts100ms = { .tv_nsec = 100000000 };
static const struct timespec ts1s = { .tv_sec = 1 };
static const struct timespec ts3s = { .tv_sec = 3 };
int main(int argc, char **argv)
{
pid_t tracee;
tracee = fork();
if (tracee == 0) {
nanosleep(&ts100ms, NULL);
while (1) {
printf("tracee: alive pid=%d\n", getpid());
nanosleep(&ts1s, NULL);
}
}
if (argc > 1)
kill(tracee, SIGSTOP);
nanosleep(&ts100ms, NULL);
ptrace(PTRACE_SEIZE, tracee, NULL,
(void *)(unsigned long)PTRACE_SEIZE_DEVEL);
if (argc > 1) {
waitid(P_PID, tracee, NULL, WSTOPPED);
ptrace(PTRACE_CONT, tracee, NULL, NULL);
}
nanosleep(&ts3s, NULL);
printf("tracer: INTERRUPT and DETACH\n");
ptrace(PTRACE_INTERRUPT, tracee, NULL, NULL);
waitid(P_PID, tracee, NULL, WSTOPPED);
ptrace(PTRACE_DETACH, tracee, NULL, NULL);
nanosleep(&ts3s, NULL);
printf("tracer: exiting\n");
kill(tracee, SIGKILL);
return 0;
}
When called without argument, tracee is seized from running state,
interrupted and then detached back to running state.
# ./test-interrupt
tracee: alive pid=4546
tracee: alive pid=4546
tracee: alive pid=4546
tracer: INTERRUPT and DETACH
tracee: alive pid=4546
tracee: alive pid=4546
tracee: alive pid=4546
tracer: exiting
When called with argument, tracee is seized from stopped state,
continued, interrupted and then detached back to stopped state.
# ./test-interrupt 1
tracee: alive pid=4548
tracee: alive pid=4548
tracee: alive pid=4548
tracer: INTERRUPT and DETACH
tracer: exiting
Before PTRACE_INTERRUPT, once the tracee was running, there was no way
to trap tracee and do PTRACE_DETACH without causing side effect.
-v2: Updated to use task_set_jobctl_pending() so that it doesn't end
up scheduling TRAP_STOP if child is dying which may make the
child unkillable. Spotted by Oleg.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
PTRACE_ATTACH implicitly issues SIGSTOP on attach which has side
effects on tracee signal and job control states. This patch
implements a new ptrace request PTRACE_SEIZE which attaches a tracee
without trapping it or affecting its signal and job control states.
The usage is the same with PTRACE_ATTACH but it takes PTRACE_SEIZE_*
flags in @data. Currently, the only defined flag is
PTRACE_SEIZE_DEVEL which is a temporary flag to enable PTRACE_SEIZE.
PTRACE_SEIZE will change ptrace behaviors outside of attach itself.
The changes will be implemented gradually and the DEVEL flag is to
prevent programs which expect full SEIZE behavior from using it before
all the behavior modifications are complete while allowing unit
testing. The flag will be removed once SEIZE behaviors are completely
implemented.
* PTRACE_SEIZE, unlike ATTACH, doesn't force tracee to trap. After
attaching tracee continues to run unless a trap condition occurs.
* PTRACE_SEIZE doesn't affect signal or group stop state.
* If PTRACE_SEIZE'd, group stop uses PTRACE_EVENT_STOP trap which uses
exit_code of (signr | PTRACE_EVENT_STOP << 8) where signr is one of
the stopping signals if group stop is in effect or SIGTRAP
otherwise, and returns usual trap siginfo on PTRACE_GETSIGINFO
instead of NULL.
Seizing sets PT_SEIZED in ->ptrace of the tracee. This flag will be
used to determine whether new SEIZE behaviors should be enabled.
Test program follows.
#define PTRACE_SEIZE 0x4206
#define PTRACE_SEIZE_DEVEL 0x80000000
static const struct timespec ts100ms = { .tv_nsec = 100000000 };
static const struct timespec ts1s = { .tv_sec = 1 };
static const struct timespec ts3s = { .tv_sec = 3 };
int main(int argc, char **argv)
{
pid_t tracee;
tracee = fork();
if (tracee == 0) {
nanosleep(&ts100ms, NULL);
while (1) {
printf("tracee: alive\n");
nanosleep(&ts1s, NULL);
}
}
if (argc > 1)
kill(tracee, SIGSTOP);
nanosleep(&ts100ms, NULL);
ptrace(PTRACE_SEIZE, tracee, NULL,
(void *)(unsigned long)PTRACE_SEIZE_DEVEL);
if (argc > 1) {
waitid(P_PID, tracee, NULL, WSTOPPED);
ptrace(PTRACE_CONT, tracee, NULL, NULL);
}
nanosleep(&ts3s, NULL);
printf("tracer: exiting\n");
return 0;
}
When the above program is called w/o argument, tracee is seized while
running and remains running. When tracer exits, tracee continues to
run and print out messages.
# ./test-seize-simple
tracee: alive
tracee: alive
tracee: alive
tracer: exiting
tracee: alive
tracee: alive
When called with an argument, tracee is seized from stopped state and
continued, and returns to stopped state when tracer exits.
# ./test-seize
tracee: alive
tracee: alive
tracee: alive
tracer: exiting
# ps -el|grep test-seize
1 T 0 4720 1 0 80 0 - 941 signal ttyS0 00:00:00 test-seize
-v2: SEIZE doesn't schedule TRAP_STOP and leaves tracee running as Jan
suggested.
-v3: PTRACE_EVENT_STOP traps now report group stop state by signr. If
group stop is in effect the stop signal number is returned as
part of exit_code; otherwise, SIGTRAP. This was suggested by
Denys and Oleg.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
do_signal_stop() implemented both normal group stop and trap for group
stop while ptraced. This approach has been enough but scheduled
changes require trap mechanism which can be used in more generic
manner and using group stop trap for generic trap site simplifies both
userland visible interface and implementation.
This patch adds a new jobctl flag - JOBCTL_TRAP_STOP. When set, it
triggers a trap site, which behaves like group stop trap, in
get_signal_to_deliver() after checking for pending signals. While
ptraced, do_signal_stop() doesn't stop itself. It initiates group
stop if requested and schedules JOBCTL_TRAP_STOP and returns. The
caller - get_signal_to_deliver() - is responsible for checking whether
TRAP_STOP is pending afterwards and handling it.
ptrace_attach() is updated to use JOBCTL_TRAP_STOP instead of
JOBCTL_STOP_PENDING and __ptrace_unlink() to clear all pending trap
bits and TRAPPING so that TRAP_STOP and future trap bits don't linger
after detach.
While at it, add proper function comment to do_signal_stop() and make
it return bool.
-v2: __ptrace_unlink() updated to clear JOBCTL_TRAP_MASK and TRAPPING
instead of JOBCTL_PENDING_MASK. This avoids accidentally
clearing JOBCTL_STOP_CONSUME. Spotted by Oleg.
-v3: do_signal_stop() updated to return %false without dropping
siglock while ptraced and TRAP_STOP check moved inside for(;;)
loop after group stop participation. This avoids unnecessary
relocking and also will help avoiding unnecessary traps by
consuming group stop before handling pending traps.
-v4: Jobctl trap handling moved into a separate function -
do_jobctl_trap().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
The clocksource watchdog code is interruptible and it has been
observed that this can trigger false positives which disable the TSC.
The reason is that an interrupt storm or a long running interrupt
handler between the read of the watchdog source and the read of the
TSC brings the two far enough apart that the delta is larger than the
unstable treshold. Move both reads into a short interrupt disabled
region to avoid that.
Reported-and-tested-by: Vernon Mauery <vernux@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
This patch #ifdefs RCU kthreads out of the kernel unless RCU_BOOST=y,
thus eliminating context-switch overhead if RCU priority boosting has
not been configured.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: Check if lowest_mask is initialized in find_lowest_rq()
sched: Fix need_resched() when checking peempt
CONFIG_CONSTRUCTORS controls support for running constructor functions at
kernel init time. According to commit b99b87f70c ("kernel:
constructor support"), gcov (CONFIG_GCOV_KERNEL) needs this. However,
CONFIG_CONSTRUCTORS currently defaults to y, with no option to disable it,
and CONFIG_GCOV_KERNEL depends on it. Instead, default it to n and have
CONFIG_GCOV_KERNEL select it, so that the normal case of
CONFIG_GCOV_KERNEL=n will result in CONFIG_CONSTRUCTORS=n.
Observed in the short list of =y values in a minimal kernel configuration.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The following crash was reported:
> Call Trace:
> [<ffffffff81139792>] mem_cgroup_from_task+0x15/0x17
> [<ffffffff8113a75a>] __mem_cgroup_try_charge+0x148/0x4b4
> [<ffffffff810493f3>] ? need_resched+0x23/0x2d
> [<ffffffff814cbf43>] ? preempt_schedule+0x46/0x4f
> [<ffffffff8113afe8>] mem_cgroup_charge_common+0x9a/0xce
> [<ffffffff8113b6d1>] mem_cgroup_newpage_charge+0x5d/0x5f
> [<ffffffff81134024>] khugepaged+0x5da/0xfaf
> [<ffffffff81078ea0>] ? __init_waitqueue_head+0x4b/0x4b
> [<ffffffff81133a4a>] ? add_mm_counter.constprop.5+0x13/0x13
> [<ffffffff81078625>] kthread+0xa8/0xb0
> [<ffffffff814d13e8>] ? sub_preempt_count+0xa1/0xb4
> [<ffffffff814d5664>] kernel_thread_helper+0x4/0x10
> [<ffffffff814ce858>] ? retint_restore_args+0x13/0x13
> [<ffffffff8107857d>] ? __init_kthread_worker+0x5a/0x5a
What happens is that khugepaged tries to charge a huge page against an mm
whose last possible owner has already exited, and the memory controller
crashes when the stale mm->owner is used to look up the cgroup to charge.
mm->owner has never been set to NULL with the last owner going away, but
nobody cared until khugepaged came along.
Even then it wasn't a problem because the final mmput() on an mm was
forced to acquire and release mmap_sem in write-mode, preventing an
exiting owner to go away while the mmap_sem was held, and until "692e0b3
mm: thp: optimize memcg charge in khugepaged", the memory cgroup charge
was protected by mmap_sem in read-mode.
Instead of going back to relying on the mmap_sem to enforce lifetime of a
task, this patch ensures that mm->owner is properly set to NULL when the
last possible owner is exiting, which the memory controller can handle
just fine.
[akpm@linux-foundation.org: tweak comments]
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Hugh Dickins <hughd@google.com>
Reported-by: Dave Jones <davej@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On system boot up, the lowest_mask is initialized with an
early_initcall(). But RT tasks may wake up on other
early_initcall() callers before the lowest_mask is initialized,
causing a system crash.
Commit "d72bce0e67 rcu: Cure load woes" was the first commit
to wake up RT tasks in early init. Before this commit this bug
should not happen.
Reported-by: Andrew Theurer <habanero@linux.vnet.ibm.com>
Tested-by: Andrew Theurer <habanero@linux.vnet.ibm.com>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20110614223657.824872966@goodmis.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The RT preempt check tests the wrong task if NEED_RESCHED is
set. It currently checks the local CPU task. It is supposed to
check the task that is running on the runqueue we are about to
wake another task on.
Signed-off-by: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20110614223657.450239027@goodmis.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix to support kernel stack trace correctly on kprobe-tracer.
Since the execution path of kprobe-based dynamic events is different
from other tracepoint-based events, normal ftrace_trace_stack() doesn't
work correctly. To fix that, this introduces ftrace_trace_stack_regs()
which traces stack via pt_regs instead of current stack register.
e.g.
# echo p schedule+4 > /sys/kernel/debug/tracing/kprobe_events
# echo 1 > /sys/kernel/debug/tracing/options/stacktrace
# echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable
# head -n 20 /sys/kernel/debug/tracing/trace
bash-2968 [000] 10297.050245: p_schedule_4: (schedule+0x4/0x4ca)
bash-2968 [000] 10297.050247: <stack trace>
=> schedule_timeout
=> n_tty_read
=> tty_read
=> vfs_read
=> sys_read
=> system_call_fastpath
kworker/0:1-2940 [000] 10297.050265: p_schedule_4: (schedule+0x4/0x4ca)
kworker/0:1-2940 [000] 10297.050266: <stack trace>
=> worker_thread
=> kthread
=> kernel_thread_helper
sshd-1132 [000] 10297.050365: p_schedule_4: (schedule+0x4/0x4ca)
sshd-1132 [000] 10297.050365: <stack trace>
=> sysret_careful
Note: Even with this fix, the first entry will be skipped
if the probe is put on the function entry area before
the frame pointer is set up (usually, that is 4 bytes
(push %bp; mov %sp %bp) on x86), because stack unwinder
depends on the frame pointer.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@gmail.com>
Link: http://lkml.kernel.org/r/20110608070934.17777.17116.stgit@fedora15
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add weak symbol of save_stack_trace_regs() as same as
save_stack_trace_tsk() since that is not implemented
except x86 yet.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@gmail.com>
Link: http://lkml.kernel.org/r/20110608070927.17777.37895.stgit@fedora15
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The tracing ring buffer is allocated from kernel memory. While
allocating a large chunk of memory, OOM might happen which destabilizes
the system. Thus random processes might get killed during the
allocation.
This patch adds __GFP_NORETRY flag to the ring buffer allocation calls
to make it fail more gracefully if the system will not be able to
complete the allocation request.
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: David Sharp <dhsharp@google.com>
Link: http://lkml.kernel.org/r/1307491302-9236-1-git-send-email-vnagarnaik@google.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch replaces the code for getting an unsigned long from a
userspace buffer by a simple call to kstroul_from_user.
This makes it easier to read and less error prone.
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Link: http://lkml.kernel.org/r/1307476707-14762-1-git-send-email-peterhuewe@gmx.de
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The function_graph tracer does not follow global context-info option.
Adding TRACE_ITER_CONTEXT_INFO trace_flags check to enable it.
With following commands:
# echo function_graph > ./current_tracer
# echo 0 > options/context-info
# cat trace
This is what it looked like before:
# tracer: function_graph
#
# TIME CPU DURATION FUNCTION CALLS
# | | | | | | | |
1) 0.079 us | } /* __vma_link_rb */
1) 0.056 us | copy_page_range();
1) | security_vm_enough_memory() {
...
This is what it looks like now:
# tracer: function_graph
#
} /* update_ts_time_stats */
timekeeping_max_deferment();
...
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1307113131-10045-6-git-send-email-jolsa@redhat.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The header display of function tracer does not follow
the context-info option, so field names are displayed even
if this option is off.
Added check for TRACE_ITER_CONTEXT_INFO trace_flags.
With following commands:
# echo function > ./current_tracer
# echo 0 > options/context-info
# cat trace
This is what it looked like before:
# tracer: function
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
add_preempt_count <-schedule
rcu_note_context_switch <-schedule
...
This is what it looks like now:
# tracer: function
#
_raw_spin_unlock_irqrestore <-hrtimer_try_to_cancel
...
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1307113131-10045-4-git-send-email-jolsa@redhat.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Functions print_graph_overhead() and print_graph_duration() displays
data for one field - DURATION.
I merged them into single function print_graph_duration(),
and added a way to display the empty parts of the field.
This way the print_graph_irq() function can use this column to display
the IRQ signs if needed and the DURATION field details stays inside
the print_graph_duration() function.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1307113131-10045-3-git-send-email-jolsa@redhat.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The display of absolute time and duration fields is based on the
latency field. This was added during the irqsoff/wakeup tracers
graph support changes.
It's causing confusion in what fields will be displayed for the
function_graph tracer itself. So I'm removing this depency, and
adding absolute time and duration fields to the preemptirqsoff
preemptoff irqsoff wakeup tracers.
With following commands:
# echo function_graph > ./current_tracer
# cat trace
This is what it looked like before:
# tracer: function_graph
#
# TIME CPU DURATION FUNCTION CALLS
# | | | | | | | |
0) 0.068 us | } /* page_add_file_rmap */
0) | _raw_spin_unlock() {
...
This is what it looks like now:
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
0) 0.068 us | } /* add_preempt_count */
0) 0.993 us | } /* vfsmount_lock_local_lock */
...
For preemptirqsoff preemptoff irqsoff wakeup tracers,
this is what it looked like before:
SNIP
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / _-=> lock-depth
# |||| /
# CPU TASK/PID ||||| DURATION FUNCTION CALLS
# | | | ||||| | | | | | |
1) <idle>-0 | d..1 0.000 us | acpi_idle_enter_simple();
...
This is what it looks like now:
SNIP
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| /
# TIME CPU TASK/PID |||| DURATION FUNCTION CALLS
# | | | | |||| | | | | | |
19.847735 | 1) <idle>-0 | d..1 0.000 us | acpi_idle_enter_simple();
...
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1307113131-10045-2-git-send-email-jolsa@redhat.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Added <linux/atomic.h>,<linux/ktime.h> and Removed <asm/atomic.h>.
Added KERN_DEBUG to printk() functions.
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Paul McQuade <tungstentide@gmail.com>
Link: http://lkml.kernel.org/r/4DE596B4.7030904@gmail.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add a trace option to disable tracing on free. When this option is
set, a write into the free_buffer file will not only shrink the
ring buffer down to zero, but it will also disable tracing.
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The proc file entry buffer_size_kb is used to set the size of tracing
buffer. The memory to expand the buffer size is kernel memory. Consider
a use case where tracing is handled by a user space utility, which acts
as a gate keeper for tracing requests. In an OOM condition, tracing is
considered a low priority task and if the utility gets killed the ring
buffer memory cannot be released back to the kernel.
This patch adds a proc file called "free_buffer" whose purpose is to
stop tracing and free up the ring buffer when it is closed.
The user space process can then set the desired size in buffer_size_kb
file and open the fd to the "free_buffer" file. Under OOM condition, if
the process gets killed, the kernel closes the file descriptor. The
release handler stops the tracing and releases the kernel memory
automatically.
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Link: http://lkml.kernel.org/r/1308012717-11148-1-git-send-email-vnagarnaik@google.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Fix kernel-doc warnings in signal.c:
Warning(kernel/signal.c:2374): No description found for parameter 'nset'
Warning(kernel/signal.c:2374): Excess function parameter 'set' description in 'sys_rt_sigprocmask'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The tracing ring buffer is a group of per-cpu ring buffers where
allocation and logging is done on a per-cpu basis. The events that are
generated on a particular CPU are logged in the corresponding buffer.
This is to provide wait-free writes between CPUs and good NUMA node
locality while accessing the ring buffer.
However, the allocation routines consider NUMA locality only for buffer
page metadata and not for the actual buffer page. This causes the pages
to be allocated on the NUMA node local to the CPU where the allocation
routine is running at the time.
This patch fixes the problem by using a NUMA node specific allocation
routine so that the pages are allocated from a NUMA node local to the
logging CPU.
I tested with the getuid_microbench from autotest. It is a simple binary
that calls getuid() in a loop and measures the average time for the
syscall to complete. The following command was used to test:
$ getuid_microbench 1000000
Compared the numbers found on kernel with and without this patch and
found that logging latency decreases by 30-50 ns/call.
tracing with non-NUMA allocation - 569 ns/call
tracing with NUMA allocation - 512 ns/call
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: David Sharp <dhsharp@google.com>
Link: http://lkml.kernel.org/r/1304470602-20366-1-git-send-email-vnagarnaik@google.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In using syscall tracing by concurrent processes, the wakeup() that is
called in the event commit function causes contention on the spin lock
of the waitqueue. I enabled sys_enter_getuid and sys_exit_getuid
tracepoints, and by running getuid_microbench from autotest in parallel
I found that the contention causes exponential latency increase in the
tracing path.
The autotest binary getuid_microbench calls getuid() in a tight loop for
the given number of iterations and measures the average time required to
complete a single invocation of syscall.
The patch schedules a delayed work after 2 ms once an event commit calls
to wake up the trace wait_queue. This removes the delay caused by
contention on spin lock in wakeup() and amortizes the wakeup() calls
scheduled over the 2 ms period.
In the following example, the script enables the sys_enter_getuid and
sys_exit_getuid tracepoints and runs the getuid_microbench in parallel
with the given number of processes. The output clearly shows the latency
increase caused by contentions.
$ ~/getuid.sh 1
1000000 calls in 0.720974253 s (720.974253 ns/call)
$ ~/getuid.sh 2
1000000 calls in 1.166457554 s (1166.457554 ns/call)
1000000 calls in 1.168933765 s (1168.933765 ns/call)
$ ~/getuid.sh 3
1000000 calls in 1.783827516 s (1783.827516 ns/call)
1000000 calls in 1.795553270 s (1795.553270 ns/call)
1000000 calls in 1.796493376 s (1796.493376 ns/call)
$ ~/getuid.sh 4
1000000 calls in 4.483041796 s (4483.041796 ns/call)
1000000 calls in 4.484165388 s (4484.165388 ns/call)
1000000 calls in 4.484850762 s (4484.850762 ns/call)
1000000 calls in 4.485643576 s (4485.643576 ns/call)
$ ~/getuid.sh 5
1000000 calls in 6.497521653 s (6497.521653 ns/call)
1000000 calls in 6.502000236 s (6502.000236 ns/call)
1000000 calls in 6.501709115 s (6501.709115 ns/call)
1000000 calls in 6.502124100 s (6502.124100 ns/call)
1000000 calls in 6.502936358 s (6502.936358 ns/call)
After the patch, the latencies scale better.
1000000 calls in 0.728720455 s (728.720455 ns/call)
1000000 calls in 0.842782857 s (842.782857 ns/call)
1000000 calls in 0.883803135 s (883.803135 ns/call)
1000000 calls in 0.902077764 s (902.077764 ns/call)
1000000 calls in 0.902838202 s (902.838202 ns/call)
1000000 calls in 0.908896885 s (908.896885 ns/call)
1000000 calls in 0.932523515 s (932.523515 ns/call)
1000000 calls in 0.958009672 s (958.009672 ns/call)
1000000 calls in 0.986188020 s (986.188020 ns/call)
1000000 calls in 0.989771102 s (989.771102 ns/call)
1000000 calls in 0.933518391 s (933.518391 ns/call)
1000000 calls in 0.958897947 s (958.897947 ns/call)
1000000 calls in 1.031038897 s (1031.038897 ns/call)
1000000 calls in 1.089516025 s (1089.516025 ns/call)
1000000 calls in 1.141998347 s (1141.998347 ns/call)
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1305059241-7629-1-git-send-email-vnagarnaik@google.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Commit a26ac2455ffcf3(rcu: move TREE_RCU from softirq to kthread)
introduced performance regression. In an AIM7 test, this commit degraded
performance by about 40%.
The commit runs rcu callbacks in a kthread instead of softirq. We observed
high rate of context switch which is caused by this. Out test system has
64 CPUs and HZ is 1000, so we saw more than 64k context switch per second
which is caused by RCU's per-CPU kthread. A trace showed that most of
the time the RCU per-CPU kthread doesn't actually handle any callbacks,
but instead just does a very small amount of work handling grace periods.
This means that RCU's per-CPU kthreads are making the scheduler do quite
a bit of work in order to allow a very small amount of RCU-related
processing to be done.
Alex Shi's analysis determined that this slowdown is due to lock
contention within the scheduler. Unfortunately, as Peter Zijlstra points
out, the scheduler's real-time semantics require global action, which
means that this contention is inherent in real-time scheduling. (Yes,
perhaps someone will come up with a workaround -- otherwise, -rt is not
going to do well on large SMP systems -- but this patch will work around
this issue in the meantime. And "the meantime" might well be forever.)
This patch therefore re-introduces softirq processing to RCU, but only
for core RCU work. RCU callbacks are still executed in kthread context,
so that only a small amount of RCU work runs in softirq context in the
common case. This should minimize ksoftirqd execution, allowing us to
skip boosting of ksoftirqd for CONFIG_RCU_BOOST=y kernels.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Tested-by: "Alex,Shi" <alex.shi@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Make the functions creating the kthreads wake them up. Leverage the
fact that the per-node and boost kthreads can run anywhere, thus
dispensing with the need to wake them up once the incoming CPU has
gone fully online.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Daniel J Blueman <daniel.blueman@gmail.com>
Create a new CONFIG_PREEMPT_COUNT that handles the inc/dec
of preempt count offset independently. So that the offset
can be updated by preempt_disable() and preempt_enable()
even without the need for CONFIG_PREEMPT beeing set.
This prepares to make CONFIG_DEBUG_SPINLOCK_SLEEP working
with !CONFIG_PREEMPT where it currently doesn't detect
code that sleeps inside explicit preemption disabled
sections.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Several fixes as well where the +1 was missing.
Done via coccinelle scripts like:
@@
struct resource *ptr;
@@
- ptr->end - ptr->start + 1
+ resource_size(ptr)
and some grep and typing.
Mostly uncompiled, no cross-compilers.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
In kernel/irq/manage.c::irq_set_irq_wake() we call
irq_get_desc_buslock() which may return NULL, but the code
dereferences the result unconditionally.
irq_set_irq_wake() has lots of callers - I checked a few and I couldn't
find anything that guarantees that they won't call it with some input that
will cause irq_get_desc_buslock() to return NULL, so I think it's a good
thing to test and -EINVAL was the most sane error code in this situation
that I could think of.
Not all callers test the return value of irq_set_irq_wake(), but those
that do take != 0 to mean error as far as I can see, so they should be
fine. I guess those that don't test actually should, but that's a
different issue.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1106092300360.17868@swampdragon.chaosbits.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The fix to fix the printk_formats of modules broke the
printk_formats of trace_printks in the kernel.
The update of what to show via the seq_file was only updated
if the passed in fmt was NULL, which happens only on the first
iteration. The result was showing the first format every time
instead of iterating through the available formats.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
We recently found that in some configurations SELinux was blocking the ability
for cgroupfs to be mounted. The reason for this is because cgroupfs creates
files and directories during the get_sb() call and also uses lookup_one_len()
during that same get_sb() call. This is a problem since the security
subsystem cannot initialize the superblock and the inodes in that filesystem
until after the get_sb() call returns. Thus we leave the inodes in
an unitialized state during get_sb(). For the vast majority of filesystems
this is not an issue, but since cgroupfs uses lookup_on_len() it does
search permission checks on the directories in the path it walks. Since the
inode security state is not set up SELinux does these checks as if the inodes
were 'unlabeled.'
Many 'normal' userspace process do not have permission to interact with
unlabeled inodes. The solution presented here is to do the permission checks
of path walk and inode creation as the kernel rather than as the task that
called mount. Since the kernel has permission to read/write/create
unlabeled inodes the get_sb() call will complete successfully and the SELinux
code will be able to initialize the superblock and those inodes created during
the get_sb() call.
This appears to be the same solution used by other filesystems such as devtmpfs
to solve the same issue and should thus have no negative impact on other LSMs
which currently work.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: James Morris <jmorris@namei.org>
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf: Fix comments in include/linux/perf_event.h
perf: Comment /proc/sys/kernel/perf_event_paranoid to be part of user ABI
perf python: Fix argument name list of read_on_cpu()
perf evlist: Don't die if sample_{id_all|type} is invalid
perf python: Use exception to propagate errors
perf evlist: Remove dependency on debug routines
perf, cgroups: Fix up for new API
It's really supposed to be defined here. If it's not then
we actually want the build to crash so that we know it,
and not keep it silent.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Revert the commit that removed the disabling of interrupts around
the initial modifying of mcount callers to nops, and update the comment.
The original comment was outdated and stated that the interrupts were
being disabled to prevent kstop machine, which was required with the
old ftrace daemon, but was no longer the case.
What the comment failed to mention was that interrupts needed to be
disabled to keep interrupts from preempting the modifying of the code
and then executing the code that was partially modified.
Revert the commit and update the comment.
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
With gcc 4.6, the self test kprobe function:
kprobe_trace_selftest_target()
is optimized such that kallsyms does not list it. The kprobes
test uses this function to insert a probe and test it. But
it will fail the test if the function is not listed in kallsyms.
Adding a __used annotation keeps the symbol in the kallsyms table.
Suggested-by: David Daney <ddaney@caviumnetworks.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
A lost Quilt refresh of 2c29ef0fef (perf: Simplify and fix
__perf_install_in_context()) is causing grief and lockups,
reported by Jiri Olsa.
When installing an event in a task context, there's a number of
issues:
- there might not be an existing task context, in which case
we should install the now current context;
- there might already be a context, not the current one, in
which case we should de-schedule the old and install the new;
these cases were dealt with in the lost refresh, however there is one
further case that was found in testing:
- there might already be a context, the current one, in which
case we should still de-schedule, and should take care
to re-install it (note that task_ctx_sched_out() clears
cpuctx->task_ctx).
Reported-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1307399008.2497.971.camel@laptop
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Release console_sem after unlocking the logbuf_lock so that we don't
generate wakeups while holding logbuf_lock. This avoids some lock
inversion troubles once we remove the lockdep_off bits between
logbuf_lock and rq->lock (prints while holding rq->lock vs doing
wakeups while holding logbuf_lock).
There's of course still an actual deadlock where the printk()s under
rq->lock will issue a wakeup from the up() call, but lockdep won't
warn about that since semaphores are not tracked.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-j8swthl12u73h4znbvitljzd@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Sergey reported a CONFIG_PROVE_RCU warning in push_rt_task where
set_task_cpu() was called with both relevant rq->locks held, which
should be sufficient for running tasks since holding its rq->lock
will serialize against sched_move_task().
Update the comments and fix the task_group() lockdep test.
Reported-and-tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1307115427.2353.3456.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The main lock_is_held() user is lockdep_assert_held(), avoid false
assertions in lockdep_off() sections by unconditionally reporting the
lock is taken.
[ the reason this is important is a lockdep_assert_held() in ttwu()
which triggers a warning under lockdep_off() as in printk() which
can trigger another wakeup and lock up due to spinlock
recursion, as reported and heroically debugged by Arne Jansen ]
Reported-and-tested-by: Arne Jansen <lists@die-jansens.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/1307398759.2497.966.camel@laptop
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kernel/trace/ftrace.c: In function 'ftrace_regex_write.clone.15':
kernel/trace/ftrace.c:2743:6: warning: 'ret' may be used uninitialized in this
function
Signed-off-by: GuoWen Li <guowen.li.linux@gmail.com>
Link: http://lkml.kernel.org/r/201106011918.47939.guowen.li.linux@gmail.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Remove the following three noop tracehooks in signals.c.
* tracehook_force_sigpending()
* tracehook_get_signal()
* tracehook_finish_jctl()
The code area is about to be updated and these hooks don't do anything
other than obfuscating the logic.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
ptracer->signal->wait_chldexit was used to wait for TRAPPING; however,
->wait_chldexit was already complicated with waker-side filtering
without adding TRAPPING wait on top of it. Also, it unnecessarily
made TRAPPING clearing depend on the current ptrace relationship - if
the ptracee is detached, wakeup is lost.
There is no reason to use signal->wait_chldexit here. We're just
waiting for JOBCTL_TRAPPING bit to clear and given the relatively
infrequent use of ptrace, bit_waitqueue can serve it perfectly.
This patch makes JOBCTL_TRAPPING wait use bit_waitqueue instead of
signal->wait_chldexit.
-v2: Use JOBCTL_*_BIT macros instead of ilog2() as suggested by Linus.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
task->jobctl currently hosts JOBCTL_STOP_PENDING and will host TRAP
pending bits too. Setting pending conditions on a dying task may make
the task unkillable. Currently, each setting site is responsible for
checking for the condition but with to-be-added job control traps this
becomes too fragile.
This patch adds task_set_jobctl_pending() which should be used when
setting task->jobctl bits to schedule a stop or trap. The function
performs the followings to ease setting pending bits.
* Sanity checks.
* If fatal signal is pending or PF_EXITING is set, no bit is set.
* STOP_SIGMASK is automatically cleared if new value is being set.
do_signal_stop() and ptrace_attach() are updated to use
task_set_jobctl_pending() instead of setting STOP_PENDING explicitly.
The surrounding structures around setting are changed to fit
task_set_jobctl_pending() better but there should be no userland
visible behavior difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
JOBCTL_TRAPPING indicates that ptracer is waiting for tracee to
(re)transit into TRACED. task_clear_jobctl_pending() must be called
when either tracee enters TRACED or the transition is cancelled for
some reason. The former is achieved by explicitly calling
task_clear_jobctl_pending() in ptrace_stop() and the latter by calling
it at the end of do_signal_stop().
Calling task_clear_jobctl_trapping() at the end of do_signal_stop()
limits the scope TRAPPING can be used and is fragile in that seemingly
unrelated changes to tracee's control flow can lead to stuck TRAPPING.
We already have task_clear_jobctl_pending() calls on those cancelling
events to clear JOBCTL_STOP_PENDING. Cancellations can be handled by
making those call sites use JOBCTL_PENDING_MASK instead and updating
task_clear_jobctl_pending() such that task_clear_jobctl_trapping() is
called automatically if no stop/trap is pending.
This patch makes the above changes and removes the fallback
task_clear_jobctl_trapping() call from do_signal_stop().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
This patch introduces JOBCTL_PENDING_MASK and replaces
task_clear_jobctl_stop_pending() with task_clear_jobctl_pending()
which takes an extra @mask argument.
JOBCTL_PENDING_MASK is currently equal to JOBCTL_STOP_PENDING but
future patches will add more bits. recalc_sigpending_tsk() is updated
to use JOBCTL_PENDING_MASK instead.
task_clear_jobctl_pending() takes @mask which in subset of
JOBCTL_PENDING_MASK and clears the relevant jobctl bits. If
JOBCTL_STOP_PENDING is set, other STOP bits are cleared together. All
task_clear_jobctl_stop_pending() users are updated to call
task_clear_jobctl_pending() with JOBCTL_STOP_PENDING which is
functionally identical to task_clear_jobctl_stop_pending().
This patch doesn't cause any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
In ptrace_stop(), after arch hook is done, the task state and jobctl
bits are updated while holding siglock. The ordering requirement
there is that TASK_TRACED is set before JOBCTL_TRAPPING is cleared to
prevent ptracer waiting on TRAPPING doesn't end up waking up TRACED is
actually set and sees TASK_RUNNING in wait(2).
Move set_current_state(TASK_TRACED) to the top of the block and
reorganize comments. This makes the ordering more obvious
(TASK_TRACED before other updates) and helps future updates to group
stop participation.
This patch doesn't cause any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
PTRACE_INTERRUPT is going to be added which should also skip
task_is_traced() check in ptrace_check_attach(). Rename @kill to
@ignore_state and make it bool. Add function comment while at it.
This patch doesn't introduce any behavior difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
signal->group_stop currently hosts mostly group stop related flags;
however, it's gonna be used for wider purposes and the GROUP_STOP_
flag prefix becomes confusing. Rename signal->group_stop to
signal->jobctl and rename all GROUP_STOP_* flags to JOBCTL_*.
Bit position macros JOBCTL_*_BIT are defined and JOBCTL_* flags are
defined in terms of them to allow using bitops later.
While at it, reassign JOBCTL_TRAPPING to bit 22 to better accomodate
future additions.
This doesn't cause any functional change.
-v2: JOBCTL_*_BIT macros added as suggested by Linus.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Remove local variable wait_trap which determines whether to wait for
!TRAPPING or not and simply wait for it if attach was successful.
-v2: Oleg pointed out wait should happen iff attach was successful.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Turns out that distro packages use this file as an indicator of
the perf event subsystem - this is easier to check for from scripts
than the existence of the system call.
This is easy enough to keep around for the kernel, so add a
comment to make sure it stays so.
Signed-off-by: Vince Weaver <vweaver1@eecs.utk.edu>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org
Cc: acme@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.00.1106031751170.29381@cl320.eecs.utk.edu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There is an optimization which does not update the timer if the timer
was pending and the expiration time was unchanged.
Since commit 3bbb9ec9 ("timers: Introduce the concept of timer slack
for legacy timers") this optimization is no longer applied for timers
where the expiration time got extended due to the slack value. So we
need to check again after the expiration time might have been updated.
[ tglx: Made it a single check by applying slack first and sorting
out the slack = 0 value (all timeouts < 256 jiffies) early ]
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Link: http://lkml.kernel.org/r/20110521105828.GA29442@Chamillionaire.breakpoint.cc
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
When irq_alloc_descs() is called with no base IRQ specified then it will
search for a range of IRQs starting from a specified base address. In the
case where an IRQ is specified it still does this search in order to ensure
that none of the requested range is already allocated and it still uses the
from parameter to specify the base for the search. This means that in the
case where a base is specified but from is zero (which is reasonable as
any IRQ number is in the range specified by a zero from) the function will
get confused and try to allocate the first suitably sized block of free IRQs
it finds.
Instead use a specified IRQ as the base address for the search, and insist
that any from that is specified can support that IRQ.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Link: http://lkml.kernel.org/r/1307037313-15733-1-git-send-email-broonie@opensource.wolfsonmicro.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The genirq changes are initializing descriptors for sparse IRQs quite
differently from how non-sparse (stacked?) IRQs are initialized, with
the effect that on my platform all IRQs are default-disabled on sparse
IRQs and default-enabled if non-sparse IRQs are used, crashing some
GPIO driver.
Fix this by refactoring the non-sparse IRQs to use the same descriptor
init function as the sparse IRQs.
Signed-off: Linus Walleij <linus.walleij@linaro.org>
Link: http://lkml.kernel.org/r/1306858479-16622-1-git-send-email-linus.walleij@stericsson.com
Cc: stable@kernel.org # 2.6.39
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The detection of spurios interrupts is currently limited to first level
handler. In force-threaded mode we never notice if the threaded irq does
not feel responsible.
This patch catches the return value of the threaded handler and forwards
it to the spurious detector. If the primary handler returns only
IRQ_WAKE_THREAD then the spourious detector ignores it because it gets
called again from the threaded handler.
[ tglx: Report the erroneous return value early and bail out ]
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Link: http://lkml.kernel.org/r/1306824972-27067-2-git-send-email-sebastian@breakpoint.cc
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
In forced threaded mode (or with an explicit threaded handler) we only
see the primary handler, but not the threaded handler.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Link: http://lkml.kernel.org/r/1306824972-27067-1-git-send-email-sebastian@breakpoint.cc
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
For UP it's stupid to request an initialized cpumask for the clock
event devices. Though we need the mask set even on UP to avoid a
horrible ifdeffery especially in the broadcast code.
For SMP we can at least try to survive with a warning and set the
cpumask of the cpu we're running on. That gives a decent chance to
bring the machine up and retrieve the debug info.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Walleij <linus.walleij@linaro.org
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Ben changed the cgroup API in commit f780bdb7c1 (cgroups: add
per-thread subsystem callbacks) in an incompatible way, but
forgot to convert the perf cgroup bits.
Avoid compile warnings and runtime splats and convert perf too ;-)
Acked-by: Ben Blum <bblum@andrew.cmu.edu>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1306767651.1200.2990.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
While looking over the code I found that with the ttwu rework the
nr_wakeups_migrate test broke since we now switch cpus prior to
calling ttwu_stat(), hence the test is always true.
Cure this by passing the migration state in wake_flags. Also move the
whole test under CONFIG_SMP, its hard to migrate tasks on UP :-)
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-pwwxl7gdqs5676f1d4cx6pj7@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Markus reported that commit 317f394160 ("sched: Move the second half
of ttwu() to the remote cpu") caused some accounting funnies on his AMD
Phenom II X4, such as weird 'top' results.
It turns out that this is due to non-synced TSC and the queued remote
wakeups stopped coupeling the two relevant cpu clocks, which leads to
wakeups seeing time jumps, which in turn lead to skewed runtime stats.
Add an explicit call to sched_clock_cpu() to couple the per-cpu clocks
to restore the normal flow of time.
Reported-and-tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1306835745.2353.3.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit cc3ce5176d (rcu: Start RCU kthreads in TASK_INTERRUPTIBLE
state) fudges a sleeping task' state, resulting in the scheduler seeing
a TASK_UNINTERRUPTIBLE task going to sleep, but a TASK_INTERRUPTIBLE
task waking up. The result is unbalanced load calculation.
The problem that patch tried to address is that the RCU threads could
stay in UNINTERRUPTIBLE state for quite a while and triggering the hung
task detector due to on-demand wake-ups.
Cure the problem differently by always giving the tasks at least one
wake-up once the CPU is fully up and running, this will kick them out of
the initial UNINTERRUPTIBLE state and into the regular INTERRUPTIBLE
wait state.
[ The alternative would be teaching kthread_create() to start threads as
INTERRUPTIBLE but that needs a tad more thought. ]
Reported-by: Damien Wyart <damien.wyart@free.fr>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul E. McKenney <paul.mckenney@linaro.org>
Link: http://lkml.kernel.org/r/1306755291.1200.2872.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Thomas Gleixner reports that we now have a boot crash triggered by
CONFIG_CPUMASK_OFFSTACK=y:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<c11ae035>] find_next_bit+0x55/0xb0
Call Trace:
[<c11addda>] cpumask_any_but+0x2a/0x70
[<c102396b>] flush_tlb_mm+0x2b/0x80
[<c1022705>] pud_populate+0x35/0x50
[<c10227ba>] pgd_alloc+0x9a/0xf0
[<c103a3fc>] mm_init+0xec/0x120
[<c103a7a3>] mm_alloc+0x53/0xd0
which was introduced by commit de03c72cfc ("mm: convert
mm->cpu_vm_cpumask into cpumask_var_t"), and is due to wrong ordering of
mm_init() vs mm_init_cpumask
Thomas wrote a patch to just fix the ordering of initialization, but I
hate the new double allocation in the fork path, so I ended up instead
doing some more radical surgery to clean it all up.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Ingo Molnar <mingo@elte.hu>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6:
x86 idle: deprecate mwait_idle() and "idle=mwait" cmdline param
x86 idle: deprecate "no-hlt" cmdline param
x86 idle APM: deprecate CONFIG_APM_CPU_IDLE
x86 idle floppy: deprecate disable_hlt()
x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it
x86 idle: clarify AMD erratum 400 workaround
idle governor: Avoid lock acquisition to read pm_qos before entering idle
cpuidle: menu: fixed wrapping timers at 4.294 seconds
Thanks to the reviews and comments by Rafael, James, Mark and Andi.
Here's version 2 of the patch incorporating your comments and also some
update to my previous patch comments.
I noticed that before entering idle state, the menu idle governor will
look up the current pm_qos target value according to the list of qos
requests received. This look up currently needs the acquisition of a
lock to access the list of qos requests to find the qos target value,
slowing down the entrance into idle state due to contention by multiple
cpus to access this list. The contention is severe when there are a lot
of cpus waking and going into idle. For example, for a simple workload
that has 32 pair of processes ping ponging messages to each other, where
64 cpu cores are active in test system, I see the following profile with
37.82% of cpu cycles spent in contention of pm_qos_lock:
- 37.82% swapper [kernel.kallsyms] [k]
_raw_spin_lock_irqsave
- _raw_spin_lock_irqsave
- 95.65% pm_qos_request
menu_select
cpuidle_idle_call
- cpu_idle
99.98% start_secondary
A better approach will be to cache the updated pm_qos target value so
reading it does not require lock acquisition as in the patch below.
With this patch the contention for pm_qos_lock is removed and I saw a
2.2X increase in throughput for my message passing workload.
cc: stable@kernel.org
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: James Bottomley <James.Bottomley@suse.de>
Acked-by: mark gross <markgross@thegnar.org>
Signed-off-by: Len Brown <len.brown@intel.com>
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: Start RCU kthreads in TASK_INTERRUPTIBLE state
rcu: Remove waitqueue usage for cpu, node, and boost kthreads
rcu: Avoid acquiring rcu_node locks in timer functions
atomic: Add atomic_or()
Documentation: Add statistics about nested locks
rcu: Decrease memory-barrier usage based on semi-formal proof
rcu: Make rcu_enter_nohz() pay attention to nesting
rcu: Don't do reschedule unless in irq
rcu: Remove old memory barriers from rcu_process_callbacks()
rcu: Add memory barriers
rcu: Fix unpaired rcu_irq_enter() from locking selftests
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (25 commits)
perf: Fix SIGIO handling
perf top: Don't stop if no kernel symtab is found
perf top: Handle kptr_restrict
perf top: Remove unused macro
perf events: initialize fd array to -1 instead of 0
perf tools: Make sure kptr_restrict warnings fit 80 col terms
perf tools: Fix build on older systems
perf symbols: Handle /proc/sys/kernel/kptr_restrict
perf: Remove duplicate headers
ftrace: Add internal recursive checks
tracing: Update btrfs's tracepoints to use u64 interface
tracing: Add __print_symbolic_u64 to avoid warnings on 32bit machine
ftrace: Set ops->flag to enabled even on static function tracing
tracing: Have event with function tracer check error return
ftrace: Have ftrace_startup() return failure code
jump_label: Check entries limit in __jump_label_update
ftrace/recordmcount: Avoid STT_FUNC symbols as base on ARM
scripts/tags.sh: Add magic for trace-events for etags too
scripts/tags.sh: Fix ctags for DEFINE_EVENT()
x86/ftrace: Fix compiler warning in ftrace.c
...
Since perf_install_in_context() will now install a context when we
add the first event, we can de-schedule the context when the last
event is removed.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110409192142.090431763@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In order to always call list_del_event() on the correct cpu if the
event is part of an active context and avoid having to do two IPIs,
change the close() semantics slightly.
The current perf_event_disable() call would disable a whole group if
the event that's being closed is the group leader, whereas the new
code keeps the group siblings enabled.
People should not rely on this behaviour and I don't think they do,
but in case we find they do, the fix is easy and we have to take the
double IPI cost.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vince Weaver <vweaver1@eecs.utk.edu>
Link: http://lkml.kernel.org/r/20110409192142.038377551@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This was scattered out - refactor it into a single function.
No change in functionality.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110409192141.979862055@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Instead of tracking if a context is active or not, track which events
of the context are active. By making it a bitmask of
EVENT_PINNED|EVENT_FLEXIBLE we can simplify some of the scheduling
routines since it can avoid adding events that are already active.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110409192141.930282378@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently __perf_install_in_context() will try and schedule in the
event irrespective of our event scheduling rules, that is, we try to
schedule CPU-pinned, TASK-pinned, CPU-flexible, TASK-flexible, but
when creating a new event we simply try and schedule it on top of
whatever is already on the PMU, this can lead to errors for pinned
events.
Therefore, simplify things and simply schedule everything out, add the
event to the corresponding context and schedule everything back in.
This also nicely handles the case where with
__ARCH_WANT_INTERRUPTS_ON_CTXSW the IPI can come right in the middle
of schedule, before we managed to call perf_event_task_sched_in().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110409192141.870894224@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Make task_ctx_sched_*() imply EVENT_ALL, since anything less will not
actually have scheduled the task in/out at all.
Since there's no site that schedules all of a task in (due to the
interleave with flexible cpuctx) we can remove this function.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110409192141.817893268@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently we only hold one ctx->lock at a time, which results in us
flipping back and forth between cpuctx->ctx.lock and task_ctx->lock.
Avoid this and gain large atomic regions by holding both locks. We
nest the task lock inside the cpu lock, since with task scheduling we
might have to change task ctx while holding the cpu ctx lock.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110409192141.769881865@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Small cleanup to how we refcount in find_get_context(), this also
allows us to use put_ctx() to free things instead of using kfree().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110409192141.719340481@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Oleg noted that ctx_sched_out() disables the PMU even though it might
not actually do something, avoid needless PMU-disabling.
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110409192141.665385503@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Upon creation, kthreads are in TASK_UNINTERRUPTIBLE state, which can
result in softlockup warnings. Because some of RCU's kthreads can
legitimately be idle indefinitely, start them in TASK_INTERRUPTIBLE
state in order to avoid those warnings.
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It is not necessary to use waitqueues for the RCU kthreads because
we always know exactly which thread is to be awakened. In addition,
wake_up() only issues an actual wakeup when there is a thread waiting on
the queue, which was why there was an extra explicit wake_up_process()
to get the RCU kthreads started.
Eliminating the waitqueues (and wake_up()) in favor of wake_up_process()
eliminates the need for the initial wake_up_process() and also shrinks
the data structure size a bit. The wakeup logic is placed in a new
rcu_wait() macro.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The rule is, we have to update tsk->rt.nr_cpus_allowed if we change
tsk->cpus_allowed. Otherwise RT scheduler may confuse.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4DD4B3FA.5060901@jp.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Dima Zavin <dima@android.com> reported:
"After pulling the thread off the run-queue during a cgroup change,
the cfs_rq.min_vruntime gets recalculated. The dequeued thread's vruntime
then gets normalized to this new value. This can then lead to the thread
getting an unfair boost in the new group if the vruntime of the next
task in the old run-queue was way further ahead."
Reported-by: Dima Zavin <dima@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Recalls-having-tested-once-upon-a-time-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1305674470-23727-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Marc reported that e4a52bcb9 (sched: Remove rq->lock from the first
half of ttwu()) broke his ARM-SMP machine. Now ARM is one of the few
__ARCH_WANT_INTERRUPTS_ON_CTXSW users, so that exception in the ttwu()
code was suspect.
Yong found that the interrupt could hit after context_switch() changes
current but before it clears p->on_cpu, if that interrupt were to
attempt a wake-up of p we would indeed find ourselves spinning in IRQ
context.
Fix this by reverting to the old behaviour for this situation and
perform a full remote wake-up.
Cc: Frank Rowand <frank.rowand@am.sony.com>
Cc: Yong Zhang <yong.zhang0@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Reported-by: Marc Zyngier <Marc.Zyngier@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
sched_domain iterations needs to be protected by rcu_read_lock() now,
this patch adds another two places which needs the rcu lock, which is
spotted by following suspicious rcu_dereference_check() usage warnings.
kernel/sched_rt.c:1244 invoked rcu_dereference_check() without protection!
kernel/sched_stats.h:41 invoked rcu_dereference_check() without protection!
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1303469634-11678-1-git-send-email-dfeng@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
PM: Fix PM QOS's user mode interface to work with ASCII input
PM / Hibernate: Update kerneldoc comments in hibernate.c
PM / Hibernate: Remove arch_prepare_suspend()
PM / Hibernate: Update some comments in core hibernate code
* 'docs-move' of git://git.kernel.org/pub/scm/linux/kernel/git/rdunlap/linux-docs:
Create Documentation/security/, move LSM-, credentials-, and keys-related files from Documentation/ to Documentation/security/, add Documentation/security/00-INDEX, and update all occurrences of Documentation/<moved_file> to Documentation/security/<moved_file>.
profile_hits() has a common check for prof_on and prof_buffer regardless
of SMP or !SMP. So, remove some duplicate code by splitting profile_hits
into two.
[akpm@linux-foundation.org: make do_profile_hits static]
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Setup and cleanup of mm_struct->exe_file is currently done in fs/proc/.
This was because exe_file was needed only for /proc/<pid>/exe. Since we
will need the exe_file functionality also for core dumps (so core name can
contain full binary path), built this functionality always into the
kernel.
To achieve that move that out of proc FS to the kernel/ where in fact it
should belong. By doing that we can make dup_mm_exe_file static. Also we
can drop linux/proc_fs.h inclusion in fs/exec.c and kernel/fork.c.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ns_cgroup is an annoying cgroup at the namespace / cgroup frontier and
leads to some problems:
* cgroup creation is out-of-control
* cgroup name can conflict when pids are looping
* it is not possible to have a single process handling a lot of
namespaces without falling in a exponential creation time
* we may want to create a namespace without creating a cgroup
The ns_cgroup was replaced by a compatibility flag 'clone_children',
where a newly created cgroup will copy the parent cgroup values.
The userspace has to manually create a cgroup and add a task to
the 'tasks' file.
This patch removes the ns_cgroup as suggested in the following thread:
https://lists.linux-foundation.org/pipermail/containers/2009-June/018616.html
The 'cgroup_clone' function is removed because it is no longer used.
This is a userspace-visible change. Commit 45531757b4 ("cgroup: notify
ns_cgroup deprecated") (merged into 2.6.27) caused the kernel to emit a
printk warning users that the feature is planned for removal. Since that
time we have heard from XXX users who were affected by this.
Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jamal Hadi Salim <hadi@cyberus.ca>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Acked-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert cgroup_attach_proc to use flex_array.
The cgroup_attach_proc implementation requires a pre-allocated array to
store task pointers to atomically move a thread-group, but asking for a
monolithic array with kmalloc() may be unreliable for very large groups.
Using flex_array provides the same functionality with less risk of
failure.
This is a post-patch for cgroup-procs-write.patch.
Signed-off-by: Ben Blum <bblum@andrew.cmu.edu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make procs file writable to move all threads by tgid at once.
Add functionality that enables users to move all threads in a threadgroup
at once to a cgroup by writing the tgid to the 'cgroup.procs' file. This
current implementation makes use of a per-threadgroup rwsem that's taken
for reading in the fork() path to prevent newly forking threads within the
threadgroup from "escaping" while the move is in progress.
Signed-off-by: Ben Blum <bblum@andrew.cmu.edu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add cgroup subsystem callbacks for per-thread attachment in atomic contexts
Add can_attach_task(), pre_attach(), and attach_task() as new callbacks
for cgroups's subsystem interface. Unlike can_attach and attach, these
are for per-thread operations, to be called potentially many times when
attaching an entire threadgroup.
Also, the old "bool threadgroup" interface is removed, as replaced by
this. All subsystems are modified for the new interface - of note is
cpuset, which requires from/to nodemasks for attach to be globally scoped
(though per-cpuset would work too) to persist from its pre_attach to
attach_task and attach.
This is a pre-patch for cgroup-procs-writable.patch.
Signed-off-by: Ben Blum <bblum@andrew.cmu.edu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Adds functionality to read/write lock CLONE_THREAD fork()ing per-threadgroup
Add an rwsem that lives in a threadgroup's signal_struct that's taken for
reading in the fork path, under CONFIG_CGROUPS. If another part of the
kernel later wants to use such a locking mechanism, the CONFIG_CGROUPS
ifdefs should be changed to a higher-up flag that CGROUPS and the other
system would both depend on.
This is a pre-patch for cgroup-procs-write.patch.
Signed-off-by: Ben Blum <bblum@andrew.cmu.edu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make pm_qos_power_write() accept values passed to it in the ASCII hex
format either with or without an ending newline.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Mark Gross <markgross@thegnar.org>
(Note: this was reverted, and is now being re-applied in pieces, with
this being the fifth and final piece. See below for the reason that
it is now felt to be safe to re-apply this.)
Commit d09b62d fixed grace-period synchronization, but left some smp_mb()
invocations in rcu_process_callbacks() that are no longer needed, but
sheer paranoia prevented them from being removed. This commit removes
them and provides a proof of correctness in their absence. It also adds
a memory barrier to rcu_report_qs_rsp() immediately before the update to
rsp->completed in order to handle the theoretical possibility that the
compiler or CPU might move massive quantities of code into a lock-based
critical section. This also proves that the sheer paranoia was not
entirely unjustified, at least from a theoretical point of view.
In addition, the old dyntick-idle synchronization depended on the fact
that grace periods were many milliseconds in duration, so that it could
be assumed that no dyntick-idle CPU could reorder a memory reference
across an entire grace period. Unfortunately for this design, the
addition of expedited grace periods breaks this assumption, which has
the unfortunate side-effect of requiring atomic operations in the
functions that track dyntick-idle state for RCU. (There is some hope
that the algorithms used in user-level RCU might be applied here, but
some work is required to handle the NMIs that user-space applications
can happily ignore. For the short term, better safe than sorry.)
This proof assumes that neither compiler nor CPU will allow a lock
acquisition and release to be reordered, as doing so can result in
deadlock. The proof is as follows:
1. A given CPU declares a quiescent state under the protection of
its leaf rcu_node's lock.
2. If there is more than one level of rcu_node hierarchy, the
last CPU to declare a quiescent state will also acquire the
->lock of the next rcu_node up in the hierarchy, but only
after releasing the lower level's lock. The acquisition of this
lock clearly cannot occur prior to the acquisition of the leaf
node's lock.
3. Step 2 repeats until we reach the root rcu_node structure.
Please note again that only one lock is held at a time through
this process. The acquisition of the root rcu_node's ->lock
must occur after the release of that of the leaf rcu_node.
4. At this point, we set the ->completed field in the rcu_state
structure in rcu_report_qs_rsp(). However, if the rcu_node
hierarchy contains only one rcu_node, then in theory the code
preceding the quiescent state could leak into the critical
section. We therefore precede the update of ->completed with a
memory barrier. All CPUs will therefore agree that any updates
preceding any report of a quiescent state will have happened
before the update of ->completed.
5. Regardless of whether a new grace period is needed, rcu_start_gp()
will propagate the new value of ->completed to all of the leaf
rcu_node structures, under the protection of each rcu_node's ->lock.
If a new grace period is needed immediately, this propagation
will occur in the same critical section that ->completed was
set in, but courtesy of the memory barrier in #4 above, is still
seen to follow any pre-quiescent-state activity.
6. When a given CPU invokes __rcu_process_gp_end(), it becomes
aware of the end of the old grace period and therefore makes
any RCU callbacks that were waiting on that grace period eligible
for invocation.
If this CPU is the same one that detected the end of the grace
period, and if there is but a single rcu_node in the hierarchy,
we will still be in the single critical section. In this case,
the memory barrier in step #4 guarantees that all callbacks will
be seen to execute after each CPU's quiescent state.
On the other hand, if this is a different CPU, it will acquire
the leaf rcu_node's ->lock, and will again be serialized after
each CPU's quiescent state for the old grace period.
On the strength of this proof, this commit therefore removes the memory
barriers from rcu_process_callbacks() and adds one to rcu_report_qs_rsp().
The effect is to reduce the number of memory barriers by one and to
reduce the frequency of execution from about once per scheduling tick
per CPU to once per grace period.
This was reverted do to hangs found during testing by Yinghai Lu and
Ingo Molnar. Frederic Weisbecker supplied Yinghai with tracing that
located the underlying problem, and Frederic also provided the fix.
The underlying problem was that the HARDIRQ_ENTER() macro from
lib/locking-selftest.c invoked irq_enter(), which in turn invokes
rcu_irq_enter(), but HARDIRQ_EXIT() invoked __irq_exit(), which
does not invoke rcu_irq_exit(). This situation resulted in calls
to rcu_irq_enter() that were not balanced by the required calls to
rcu_irq_exit(). Therefore, after these locking selftests completed,
RCU's dyntick-idle nesting count was a large number (for example,
72), which caused RCU to to conclude that the affected CPU was not in
dyntick-idle mode when in fact it was.
RCU would therefore incorrectly wait for this dyntick-idle CPU, resulting
in hangs.
In contrast, with Frederic's patch, which replaces the irq_enter()
in HARDIRQ_ENTER() with an __irq_enter(), these tests don't ever call
either rcu_irq_enter() or rcu_irq_exit(), which works because the CPU
running the test is already marked as not being in dyntick-idle mode.
This means that the rcu_irq_enter() and rcu_irq_exit() calls and RCU
then has no problem working out which CPUs are in dyntick-idle mode and
which are not.
The reason that the imbalance was not noticed before the barrier patch
was applied is that the old implementation of rcu_enter_nohz() ignored
the nesting depth. This could still result in delays, but much shorter
ones. Whenever there was a delay, RCU would IPI the CPU with the
unbalanced nesting level, which would eventually result in rcu_enter_nohz()
being called, which in turn would force RCU to see that the CPU was in
dyntick-idle mode.
The reason that very few people noticed the problem is that the mismatched
irq_enter() vs. __irq_exit() occured only when the kernel was built with
CONFIG_DEBUG_LOCKING_API_SELFTESTS.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The old version of rcu_enter_nohz() forced RCU into nohz mode even if
the nesting count was non-zero. This change causes rcu_enter_nohz()
to hold off for non-zero nesting counts.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Condition the set_need_resched() in rcu_irq_exit() on in_irq(). This
should be a no-op, because rcu_irq_exit() should only be called from irq.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Merge reason: Linus applied an overlapping commit:
5f2e8e2b0b: kernel/watchdog.c: Use proper ANSI C prototypes
So merge it in to make sure we can iterate the file without conflicts.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
commit 4b06042(bitmap, irq: add smp_affinity_list interface to
/proc/irq) causes the following warning:
[ 274.239500] WARNING: at fs/proc/generic.c:850 remove_proc_entry+0x24c/0x27a()
[ 274.251761] remove_proc_entry: removing non-empty directory 'irq/184',
leaking at least 'smp_affinity_list'
Remove the new file in the exit path.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Mike Travis <travis@sgi.com>
Link: http://lkml.kernel.org/r/4DDDE094.6050505@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Witold reported a reboot caused by the selftests of the dynamic function
tracer. He sent me a config and I used ktest to do a config_bisect on it
(as my config did not cause the crash). It pointed out that the problem
config was CONFIG_PROVE_RCU.
What happened was that if multiple callbacks are attached to the
function tracer, we iterate a list of callbacks. Because the list is
managed by synchronize_sched() and preempt_disable, the access to the
pointers uses rcu_dereference_raw().
When PROVE_RCU is enabled, the rcu_dereference_raw() calls some
debugging functions, which happen to be traced. The tracing of the debug
function would then call rcu_dereference_raw() which would then call the
debug function and then... well you get the idea.
I first wrote two different patches to solve this bug.
1) add a __rcu_dereference_raw() that would not do any checks.
2) add notrace to the offending debug functions.
Both of these patches worked.
Talking with Paul McKenney on IRC, he suggested to add recursion
detection instead. This seemed to be a better solution, so I decided to
implement it. As the task_struct already has a trace_recursion to detect
recursion in the ring buffer, and that has a very small number it
allows, I decided to use that same variable to add flags that can detect
the recursion inside the infrastructure of the function tracer.
I plan to change it so that the task struct bit can be checked in
mcount, but as that requires changes to all archs, I will hold that off
to the next merge window.
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1306348063.1465.116.camel@gandalf.stny.rr.com
Reported-by: Witold Baryluk <baryluk@smp.if.uj.edu.pl>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Filesystem, like Btrfs, has some "ULL" macros, and when these macros are passed
to tracepoints'__print_symbolic(), there will be 64->32 truncate WARNINGS during
compiling on 32bit box.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/4DACE6E0.7000507@cn.fujitsu.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When dynamic ftrace is not configured, the ops->flags still needs
to have its FTRACE_OPS_FL_ENABLED bit set in ftrace_startup().
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The self tests for event tracer does not check if the function
tracing was successfully activated. It needs to before it continues
the tests, otherwise the wrong errors may be reported.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The register_ftrace_function() returns an error code on failure
except if the call to ftrace_startup() fails. Add a error return to
ftrace_startup() if it fails to start, allowing register_ftrace_funtion()
to return a proper error value.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/linux-2.6-nsfd:
net: fix get_net_ns_by_fd for !CONFIG_NET_NS
ns proc: Return -ENOENT for a nonexistent /proc/self/ns/ entry.
ns: Declare sys_setns in syscalls.h
net: Allow setting the network namespace by fd
ns proc: Add support for the ipc namespace
ns proc: Add support for the uts namespace
ns proc: Add support for the network namespace.
ns: Introduce the setns syscall
ns: proc files for namespace naming policy.
When iterating the jump_label entries array (core or modules),
the __jump_label_update function peeks over the last entry.
The reason is that the end of the for loop depends on the key
value of the processed entry. Thus when going through the
last array entry, we will touch the memory behind the array
limit.
This bug probably will never be triggered, since most likely the
memory behind the jump_label entries will be accesable and the
entry->key will be different than the expected value.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Link: http://lkml.kernel.org/r/20110510104346.GC1899@jolsa.brq.redhat.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* 'for-2.6.40' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc:
signal: sys_pause() should check signal_pending()
ptrace: ptrace_resume() shouldn't wake up !TASK_TRACED thread
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: (26 commits)
arch/tile: prefer "tilepro" as the name of the 32-bit architecture
compat: include aio_abi.h for aio_context_t
arch/tile: cleanups for tilegx compat mode
arch/tile: allocate PCI IRQs later in boot
arch/tile: support signal "exception-trace" hook
arch/tile: use better definitions of xchg() and cmpxchg()
include/linux/compat.h: coding-style fixes
tile: add an RTC driver for the Tilera hypervisor
arch/tile: finish enabling support for TILE-Gx 64-bit chip
compat: fixes to allow working with tile arch
arch/tile: update defconfig file to something more useful
tile: do_hardwall_trap: do not play with task->sighand
tile: replace mm->cpu_vm_mask with mm_cpumask()
tile,mn10300: add device parameter to dma_cache_sync()
audit: support the "standard" <asm-generic/unistd.h>
arch/tile: clarify flush_buffer()/finv_buffer() function names
arch/tile: kernel-related cleanups from removing static page size
arch/tile: various header improvements for building drivers
arch/tile: disable GX prefetcher during cache flush
arch/tile: tolerate disabling CONFIG_BLK_DEV_INITRD
...
commit 9ec2690758 ("timerfd: Manage cancelable timers in timerfd")
introduced a CONFIG_HIGHRES_TIMERS (should be CONFIG_HIGH_RES_TIMERS)
typo, which caused applications depending on CLOCK_REALTIME timers to
become sluggy due to the fact that the time base of the realtime
timers was not updated when the wall clock time was set.
This causes anything from 100% CPU use for some applications to odd
delays and hickups.
Reported-bisected-and-tested-by: Anca Emanuel <anca.emanuel@gmail.com>
Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Fatfingered-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ERESTART* is always wrong without TIF_SIGPENDING. Teach sys_pause()
to handle the spurious wakeup correctly.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
It is not clear why ptrace_resume() does wake_up_process(). Unless the
caller is PTRACE_KILL the tracee should be TASK_TRACED so we can use
wake_up_state(__TASK_TRACED). If sys_ptrace() races with SIGKILL we do
not need the extra and potentionally spurious wakeup.
If the caller is PTRACE_KILL, wake_up_process() is even more wrong.
The tracee can sleep in any state in any place, and if we have a buggy
code which doesn't handle a spurious wakeup correctly PTRACE_KILL can
be used to exploit it. For example:
int main(void)
{
int child, status;
child = fork();
if (!child) {
int ret;
assert(ptrace(PTRACE_TRACEME, 0,0,0) == 0);
ret = pause();
printf("pause: %d %m\n", ret);
return 0x23;
}
sleep(1);
assert(ptrace(PTRACE_KILL, child, 0,0) == 0);
assert(child == wait(&status));
printf("wait: %x\n", status);
return 0;
}
prints "pause: -1 Unknown error 514", -ERESTARTNOHAND leaks to the
userland. In this case sys_pause() is buggy as well and should be
fixed.
I do not know what was the original rationality behind PTRACE_KILL.
The man page is simply wrong and afaics it was always wrong. Imho
it should be deprecated, or may be it should do send_sig(SIGKILL)
as Denys suggests, but in any case I do not think that the current
behaviour was intentional.
Note: there is another problem, ptrace_resume() changes ->exit_code
and this can race with SIGKILL too. Eventually we should change ptrace
to not use ->exit_code.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
On larger systems, because of the numerous ACPI, Bootmem and EFI messages,
the static log buffer overflows before the larger one specified by the
log_buf_len param is allocated. Minimize the overflow by allocating the
new log buffer as soon as possible.
On kernels without memblock, a later call to setup_log_buf from
kernel/init.c is the fallback.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix CONFIG_PRINTK=n build]
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Manually adjusting the smp_affinity for IRQ's becomes unwieldy when the
cpu count is large.
Setting smp affinity to cpus 256 to 263 would be:
echo 000000ff,00000000,00000000,00000000,00000000,00000000,00000000,00000000 > smp_affinity
instead of:
echo 256-263 > smp_affinity_list
Think about what it looks like for cpus around say, 4088 to 4095.
We already have many alternate "list" interfaces:
/sys/devices/system/cpu/cpuX/indexY/shared_cpu_list
/sys/devices/system/cpu/cpuX/topology/thread_siblings_list
/sys/devices/system/cpu/cpuX/topology/core_siblings_list
/sys/devices/system/node/nodeX/cpulist
/sys/devices/pci***/***/local_cpulist
Add a companion interface, smp_affinity_list to use cpu lists instead of
cpu maps. This conforms to other companion interfaces where both a map
and a list interface exists.
This required adding a bitmap_parselist_user() function in a manner
similar to the bitmap_parse_user() function.
[akpm@linux-foundation.org: make __bitmap_parselist() static]
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
cpumask_t is very big struct and cpu_vm_mask is placed wrong position.
It might lead to reduce cache hit ratio.
This patch has two change.
1) Move the place of cpumask into last of mm_struct. Because usually cpumask
is accessed only front bits when the system has cpu-hotplug capability
2) Convert cpu_vm_mask into cpumask_var_t. It may help to reduce memory
footprint if cpumask_size() will use nr_cpumask_bits properly in future.
In addition, this patch change the name of cpu_vm_mask with cpu_vm_mask_var.
It may help to detect out of tree cpu_vm_mask users.
This patch has no functional change.
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Straightforward conversion of i_mmap_lock to a mutex.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh says:
"The only significant loser, I think, would be page reclaim (when
concurrent with truncation): could spin for a long time waiting for
the i_mmap_mutex it expects would soon be dropped? "
Counter points:
- cpu contention makes the spin stop (need_resched())
- zap pages should be freeing pages at a higher rate than reclaim
ever can
I think the simplification of the truncate code is definitely worth it.
Effectively reverts: 2aa15890f3 ("mm: prevent concurrent
unmap_mapping_range() on the same inode") and takes out the code that
caused its problem.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In order to convert i_mmap_lock to a mutex we need a mutex equivalent to
spin_lock_nest_lock(), thus provide the mutex_lock_nest_lock() annotation.
As with spin_lock_nest_lock(), mutex_lock_nest_lock() allows annotation of
the locking pattern where an outer lock serializes the acquisition order
of nested locks. That is, if every time you lock multiple locks A, say A1
and A2 you first acquire N, the order of acquiring A1 and A2 is
irrelevant.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some of the kerneldoc comments in kernel/power/hibernate.c are
outdated and some of them don't adhere to the kernel's standards.
Update them and make them look in a consistent way.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
All architectures supporting hibernation define
arch_prepare_suspend() as an empty function, so remove it.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (43 commits)
TOMOYO: Fix wrong domainname validation.
SELINUX: add /sys/fs/selinux mount point to put selinuxfs
CRED: Fix load_flat_shared_library() to initialise bprm correctly
SELinux: introduce path_has_perm
flex_array: allow 0 length elements
flex_arrays: allow zero length flex arrays
flex_array: flex_array_prealloc takes a number of elements, not an end
SELinux: pass last path component in may_create
SELinux: put name based create rules in a hashtable
SELinux: generic hashtab entry counter
SELinux: calculate and print hashtab stats with a generic function
SELinux: skip filename trans rules if ttype does not match parent dir
SELinux: rename filename_compute_type argument to *type instead of *con
SELinux: fix comment to state filename_compute_type takes an objname not a qstr
SMACK: smack_file_lock can use the struct path
LSM: separate LSM_AUDIT_DATA_DENTRY from LSM_AUDIT_DATA_PATH
LSM: split LSM_AUDIT_DATA_FS into _PATH and _INODE
SELINUX: Make selinux cache VFS RCU walks safe
SECURITY: Move exec_permission RCU checks into security modules
SELinux: security_read_policy should take a size_t not ssize_t
...
* 'for-2.6.40' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu: Unify input section names
percpu: Avoid extra NOP in percpu_cmpxchg16b_double
percpu: Cast away printk format warning
percpu: Always align percpu output section to PAGE_SIZE
Fix up fairly trivial conflict in arch/x86/include/asm/percpu.h as per Tejun
Ben Nagy reported a scalability problem with KVM/QEMU that hit very hard
a single spinlock (idr_lock) in posix-timers code, on its 48 core
machine.
Even on a 16 cpu machine (2x4x2), a single test can show 98% of cpu time
used in ticket_spin_lock, from lock_timer
Ref: http://www.spinics.net/lists/kvm/msg51526.html
Switching to RCU is quite easy, IDR being already RCU ready. idr_lock
should be locked only for an insert/delete, not a lookup.
Benchmark on a 2x4x2 machine, 16 processes calling timer_gettime().
Before :
real 1m18.669s
user 0m1.346s
sys 1m17.180s
After :
real 0m3.296s
user 0m1.366s
sys 0m1.926s
Reported-by: Ben Nagy <ben@iagu.net>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Ben Nagy <ben@iagu.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Richard Cochran <richard.cochran@omicron.at>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf tools: Fix sample type size calculation in 32 bits archs
profile: Use vzalloc() rather than vmalloc() & memset()
We try to enforce it by using -Wstrict-prototypes, but apparently they
sometimes get through. Introduced by 4eec42f392 ("watchdog: Change
the default timeout and configure nmi watchdog period based").
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This build warning slipped through:
kernel/watchdog.c:102: warning: function declaration isn't a prototype
As reported by Stephen Rothwell.
Also address an unused variable warning that GCC 4.6.0 reports:
we cannot do anything about failed watchdog ops during CPU hotplug
(it's not serious enough to return an error from the notifier),
so ignore them.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20110524134129.8da27016.sfr@canb.auug.org.au
Signed-off-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20110517071642.GF22305@elte.hu>
Some comments in the core hibernate code are outdated, some aren't
necessary any more and at least one of them is plain wrong. Remove
those comments or update them.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* 'staging-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6: (970 commits)
staging: usbip: replace usbip_u{dbg,err,info} and printk with dev_ and pr_
staging:iio: Trivial kconfig reorganization and uniformity improvements.
staging:iio:documenation partial update.
staging:iio: use pollfunc allocation helpers in remaining drivers.
staging:iio:max1363 misc cleanups and use of for_each_bit_set to simplify event code spitting out.
staging:iio: implement an iio_info structure to take some of the constant elements out of iio_dev.
staging:iio:meter:ade7758: Use private data space from iio_allocate_device
staging:iio:accel:lis3l02dq make write_reg_8 take value not a pointer to value.
staging:iio: ring core cleanups + check if read_last available in lis3l02dq
staging:iio:core cleanup: squash tiny wrappers and use dev_set_name to handle creation of event interface name.
staging:iio: poll func allocation clean up.
staging:iio:ad7780 trivial unused header cleanup.
staging:iio:adc: AD7780: Use private data space from iio_allocate_device + trivial fixes
staging:iio:adc:AD7780: Convert to new channel registration method
staging:iio:adc: AD7606: Drop dev_data in favour of iio_priv()
staging:iio:adc: AD7606: Consitently use indio_dev
staging:iio: Rip out helper for software rings.
staging:iio:adc:AD7298: Use private data space from iio_allocate_device
staging:iio: rationalization of different buffer implementation hooks.
staging:iio:imu:adis16400 avoid allocating rx, tx, and state separately from iio_dev.
...
Fix up trivial conflicts in
- drivers/staging/intel_sst/intelmid.c: patches applied in both branches
- drivers/staging/rt2860/common/cmm_data_{pci,usb}.c: removed vs spelling
- drivers/staging/usbip/vhci_sysfs.c: trivial header file inclusion
* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
hrtimers: Reorder clock bases
hrtimers: Avoid touching inactive timer bases
hrtimers: Make struct hrtimer_cpu_base layout less stupid
timerfd: Manage cancelable timers in timerfd
clockevents: Move C3 stop test outside lock
alarmtimer: Drop device refcount after rtc_open()
alarmtimer: Check return value of class_find_device()
timerfd: Allow timers to be cancelled when clock was set
hrtimers: Prepare for cancel on clock was set timers
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf tools: Fix sample size bit operations
perf tools: Fix ommitted mmap data update on remap
watchdog: Change the default timeout and configure nmi watchdog period based on watchdog_thresh
watchdog: Disable watchdog when thresh is zero
watchdog: Only disable/enable watchdog if neccessary
watchdog: Fix rounding bug in get_sample_period()
perf tools: Propagate event parse error handling
perf tools: Robustify dynamic sample content fetch
perf tools: Pre-check sample size before parsing
perf tools: Move evlist sample helpers to evlist area
perf tools: Remove junk code in mmap size handling
perf tools: Check we are able to read the event size on mmap
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
b43: fix comment typo reqest -> request
Haavard Skinnemoen has left Atmel
cris: typo in mach-fs Makefile
Kconfig: fix copy/paste-ism for dell-wmi-aio driver
doc: timers-howto: fix a typo ("unsgined")
perf: Only include annotate.h once in tools/perf/util/ui/browsers/annotate.c
md, raid5: Fix spelling error in comment ('Ofcourse' --> 'Of course').
treewide: fix a few typos in comments
regulator: change debug statement be consistent with the style of the rest
Revert "arm: mach-u300/gpio: Fix mem_region resource size miscalculations"
audit: acquire creds selectively to reduce atomic op overhead
rtlwifi: don't touch with treewide double semicolon removal
treewide: cleanup continuations and remove logging message whitespace
ath9k_hw: don't touch with treewide double semicolon removal
include/linux/leds-regulator.h: fix syntax in example code
tty: fix typo in descripton of tty_termios_encode_baud_rate
xtensa: remove obsolete BKL kernel option from defconfig
m68k: fix comment typo 'occcured'
arch:Kconfig.locks Remove unused config option.
treewide: remove extra semicolons
...
The ordering of the clock bases is historical due to the
CLOCK_REALTIME and CLOCK_MONOTONIC constants. Now the hrtimer bases
have their own enumeration due to the gap between CLOCK_MONOTONIC and
CLOCK_BOOTTIME. So we can be more clever as most timers end up on the
CLOCK_MONOTONIC base due to the virtue of POSIX declaring that
relative CLOCK_REALTIME timers are not affected by time changes. In
desktop environments this is slowly changing as applications switch to
absolute timers, but I've observed empty CLOCK_REALTIME bases often
enough. There is no performance penalty or overhead when
CLOCK_REALTIME timers are active, but in case they are not we don't
skip over a full cache line.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
Instead of iterating over all possible timer bases avoid it by marking
the active bases in the cpu base.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
Peter is concerned about the extra scan of CLOCK_REALTIME_COS in the
timer interrupt. Yes, I did not think about it, because the solution
was so elegant. I didn't like the extra list in timerfd when it was
proposed some time ago, but with a rcu based list the list walk it's
less horrible than the original global lock, which was held over the
list iteration.
Requested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
Before the conversion of the NMI watchdog to perf event, the
watchdog timeout was 5 seconds. Now it is 60 seconds. For my
particular application, netbooks, 5 seconds was a better
timeout. With a short timeout, we catch faults earlier and are
able to send back a panic. With a 60 second timeout, the user is
unlikely to wait and will instead hit the power button, causing
us to lose the panic info.
This change configures the NMI period to watchdog_thresh and
sets the softlockup_thresh to watchdog_thresh * 2. In addition,
watchdog_thresh was reduced to 10 seconds as suggested by Ingo
Molnar.
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1306127423-3347-4-git-send-email-msb@chromium.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20110517071642.GF22305@elte.hu>
This restores the previous behavior of softlock_thresh.
Currently, setting watchdog_thresh to zero causes the watchdog
kthreads to consume a lot of CPU.
In addition, the logic of proc_dowatchdog_thresh and
proc_dowatchdog_enabled has been factored into proc_dowatchdog.
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1306127423-3347-3-git-send-email-msb@chromium.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20110517071018.GE22305@elte.hu>
Don't take any action on an unsuccessful write to /proc.
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1306127423-3347-2-git-send-email-msb@chromium.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In get_sample_period(), softlockup_thresh is integer divided by
5 before the multiplication by NSEC_PER_SEC. This results in
softlockup_thresh being rounded down to the nearest integer
multiple of 5.
For example, a softlockup_thresh of 4 rounds down to 0.
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1306127423-3347-1-git-send-email-msb@chromium.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next-2.6: (28 commits)
sparc32: fix build, fix missing cpu_relax declaration
SCHED_TTWU_QUEUE is not longer needed since sparc32 now implements IPI
sparc32,leon: Remove unnecessary page_address calls in LEON DMA API.
sparc: convert old cpumask API into new one
sparc32, sun4d: Implemented SMP IPIs support for SUN4D machines
sparc32, sun4m: Implemented SMP IPIs support for SUN4M machines
sparc32,leon: Implemented SMP IPIs for LEON CPU
sparc32: implement SMP IPIs using the generic functions
sparc32,leon: SMP power down implementation
sparc32,leon: added some SMP comments
sparc: add {read,write}*_be routines
sparc32,leon: don't rely on bootloader to mask IRQs
sparc32,leon: operate on boot-cpu IRQ controller registers
sparc32: always define boot_cpu_id
sparc32: removed unused code, implemented by generic code
sparc32: avoid build warning at mm/percpu.c:1647
sparc32: always register a PROM based early console
sparc32: probe for cpu info only during startup
sparc: consolidate show_cpuinfo in cpu.c
sparc32,leon: implement genirq CPU affinity
...
When building with:
CONFIG_64BIT=y
CONFIG_MIPS32_COMPAT=y
CONFIG_COMPAT=y
CONFIG_MIPS32_O32=y
CONFIG_MIPS32_N32=y
CONFIG_SYSVIPC is not set
(and implicitly: CONFIG_SYSVIPC_COMPAT is not set)
the final link fails with unresolved symbols for:
compat_sys_semctl, compat_sys_msgsnd, compat_sys_msgrcv,
compat_sys_shmctl, compat_sys_msgctl, compat_sys_semtimedop
The fix is to add cond_syscall declarations for all syscalls in
ipc/compat.c
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1446 commits)
macvlan: fix panic if lowerdev in a bond
tg3: Add braces around 5906 workaround.
tg3: Fix NETIF_F_LOOPBACK error
macvlan: remove one synchronize_rcu() call
networking: NET_CLS_ROUTE4 depends on INET
irda: Fix error propagation in ircomm_lmp_connect_response()
irda: Kill set but unused variable 'bytes' in irlan_check_command_param()
irda: Kill set but unused variable 'clen' in ircomm_connect_indication()
rxrpc: Fix set but unused variable 'usage' in rxrpc_get_transport()
be2net: Kill set but unused variable 'req' in lancer_fw_download()
irda: Kill set but unused vars 'saddr' and 'daddr' in irlan_provider_connect_indication()
atl1c: atl1c_resume() is only used when CONFIG_PM_SLEEP is defined.
rxrpc: Fix set but unused variable 'usage' in rxrpc_get_peer().
rxrpc: Kill set but unused variable 'local' in rxrpc_UDP_error_handler()
rxrpc: Kill set but unused variable 'sp' in rxrpc_process_connection()
rxrpc: Kill set but unused variable 'sp' in rxrpc_rotate_tx_window()
pkt_sched: Kill set but unused variable 'protocol' in tc_classify()
isdn: capi: Use pr_debug() instead of ifdefs.
tg3: Update version to 3.119
tg3: Apply rx_discards fix to 5719/5720
...
Fix up trivial conflicts in arch/x86/Kconfig and net/mac80211/agg-tx.c
as per Davem.
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
MAINTAINERS: Add drivers/clocksource to TIMEKEEPING
clockevents/source: Use u64 to make 32bit happy
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
extable, core_kernel_data(): Make sure all archs define _sdata
core_kernel_data(): Fix architectures that do not define _sdata
Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit e66eed651f ("list: remove prefetching from regular list
iterators") removed the include of prefetch.h from list.h, which
uncovered several cases that had apparently relied on that rather
obscure header file dependency.
So this fixes things up a bit, using
grep -L linux/prefetch.h $(git grep -l '[^a-z_]prefetchw*(' -- '*.[ch]')
grep -L 'prefetchw*(' $(git grep -l 'linux/prefetch.h' -- '*.[ch]')
to guide us in finding files that either need <linux/prefetch.h>
inclusion, or have it despite not needing it.
There are more of them around (mostly network drivers), but this gets
many core ones.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce SCHED_LOAD_RESOLUTION, which scales is added to
SCHED_LOAD_SHIFT and increases the resolution of
SCHED_LOAD_SCALE. This patch sets the value of
SCHED_LOAD_RESOLUTION to 10, scaling up the weights for all
sched entities by a factor of 1024. With this extra resolution,
we can handle deeper cgroup hiearchies and the scheduler can do
better shares distribution and load load balancing on larger
systems (especially for low weight task groups).
This does not change the existing user interface, the scaled
weights are only used internally. We do not modify
prio_to_weight values or inverses, but use the original weights
when calculating the inverse which is used to scale execution
time delta in calc_delta_mine(). This ensures we do not lose
accuracy when accounting time to the sched entities. Thanks to
Nikunj Dadhania for fixing an bug in c_d_m() that broken fairness.
Below is some analysis of the performance costs/improvements of
this patch.
1. Micro-arch performance costs:
Experiment was to run Ingo's pipe_test_100k 200 times with the
task pinned to one cpu. I measured instruction, cycles and
stalled-cycles for the runs. See:
http://thread.gmane.org/gmane.linux.kernel/1129232/focus=1129389
for more info.
-tip (baseline):
Performance counter stats for '/root/load-scale/pipe-test-100k' (200 runs):
964,991,769 instructions # 0.82 insns per cycle
# 0.33 stalled cycles per insn
# ( +- 0.05% )
1,171,186,635 cycles # 0.000 GHz ( +- 0.08% )
306,373,664 stalled-cycles-backend # 26.16% backend cycles idle ( +- 0.28% )
314,933,621 stalled-cycles-frontend # 26.89% frontend cycles idle ( +- 0.34% )
1.122405684 seconds time elapsed ( +- 0.05% )
-tip+patches:
Performance counter stats for './load-scale/pipe-test-100k' (200 runs):
963,624,821 instructions # 0.82 insns per cycle
# 0.33 stalled cycles per insn
# ( +- 0.04% )
1,175,215,649 cycles # 0.000 GHz ( +- 0.08% )
315,321,126 stalled-cycles-backend # 26.83% backend cycles idle ( +- 0.28% )
316,835,873 stalled-cycles-frontend # 26.96% frontend cycles idle ( +- 0.29% )
1.122238659 seconds time elapsed ( +- 0.06% )
With this patch, instructions decrease by ~0.10% and cycles
increase by 0.27%. This doesn't look statistically significant.
The number of stalled cycles in the backend increased from
26.16% to 26.83%. This can be attributed to the shifts we do in
c_d_m() and other places. The fraction of stalled cycles in the
frontend remains about the same, at 26.96% compared to 26.89% in -tip.
2. Balancing low-weight task groups
Test setup: run 50 tasks with random sleep/busy times (biased
around 100ms) in a low weight container (with cpu.shares = 2).
Measure %idle as reported by mpstat over a 10s window.
-tip (baseline):
06:47:48 PM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle intr/s
06:47:49 PM all 94.32 0.00 0.06 0.00 0.00 0.00 0.00 0.00 5.62 15888.00
06:47:50 PM all 94.57 0.00 0.62 0.00 0.00 0.00 0.00 0.00 4.81 16180.00
06:47:51 PM all 94.69 0.00 0.06 0.00 0.00 0.00 0.00 0.00 5.25 15966.00
06:47:52 PM all 95.81 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.19 16053.00
06:47:53 PM all 94.88 0.06 0.00 0.00 0.00 0.00 0.00 0.00 5.06 15984.00
06:47:54 PM all 93.31 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6.69 15806.00
06:47:55 PM all 94.19 0.00 0.06 0.00 0.00 0.00 0.00 0.00 5.75 15896.00
06:47:56 PM all 92.87 0.00 0.00 0.00 0.00 0.00 0.00 0.00 7.13 15716.00
06:47:57 PM all 94.88 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.12 15982.00
06:47:58 PM all 95.44 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.56 16075.00
Average: all 94.49 0.01 0.08 0.00 0.00 0.00 0.00 0.00 5.42 15954.60
-tip+patches:
06:47:03 PM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle intr/s
06:47:04 PM all 100.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 16630.00
06:47:05 PM all 99.69 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.31 16580.20
06:47:06 PM all 99.69 0.00 0.06 0.00 0.00 0.00 0.00 0.00 0.25 16596.00
06:47:07 PM all 99.20 0.00 0.74 0.00 0.00 0.06 0.00 0.00 0.00 17838.61
06:47:08 PM all 100.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 16540.00
06:47:09 PM all 100.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 16575.00
06:47:10 PM all 100.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 16614.00
06:47:11 PM all 99.94 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.06 16588.00
06:47:12 PM all 99.94 0.00 0.06 0.00 0.00 0.00 0.00 0.00 0.00 16593.00
06:47:13 PM all 99.94 0.00 0.06 0.00 0.00 0.00 0.00 0.00 0.00 16551.00
Average: all 99.84 0.00 0.09 0.00 0.00 0.01 0.00 0.00 0.06 16711.58
We see an improvement in idle% on the system (drops from 5.42% on -tip to 0.06%
with the patches).
We see an improvement in idle% on the system (drops from 5.42%
on -tip to 0.06% with the patches).
Signed-off-by: Nikhil Rao <ncrao@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Stephan Barwolf <stephan.baerwolf@tu-ilmenau.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1305754668-18792-1-git-send-email-ncrao@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
SCHED_LOAD_SCALE is used to increase nice resolution and to
scale cpu_power calculations in the scheduler. This patch
introduces SCHED_POWER_SCALE and converts all uses of
SCHED_LOAD_SCALE for scaling cpu_power to use SCHED_POWER_SCALE
instead.
This is a preparatory patch for increasing the resolution of
SCHED_LOAD_SCALE, and there is no need to increase resolution
for cpu_power calculations.
Signed-off-by: Nikhil Rao <ncrao@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Stephan Barwolf <stephan.baerwolf@tu-ilmenau.de>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/1305738580-9924-3-git-send-email-ncrao@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Avoid using long repetitious names; make this simpler and nicer
to read. No functional change introduced in this patch.
Signed-off-by: Nikhil Rao <ncrao@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Stephan Barwolf <stephan.baerwolf@tu-ilmenau.de>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/1305738580-9924-2-git-send-email-ncrao@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There are users which want to drain workqueues without destroying it.
Separate out drain functionality from destroy_workqueue() into
drain_workqueue() and make it accessible to workqueue users.
To guarantee forward-progress, only chain queueing is allowed while
drain is in progress. If a new work item which isn't chained from the
running or pending work items is queued while draining is in progress,
WARN_ON_ONCE() is triggered.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
A new utility function (core_kernel_data()) is used to determine if a
passed in address is part of core kernel data or not. It may or may not
return true for RO data, but this utility must work for RW data.
Thus both _sdata and _edata must be defined and continuous,
without .init sections that may later be freed and replaced by
volatile memory (memory that can be freed).
This utility function is used to determine if data is safe from
ever being freed. Thus it should return true for all RW global
data that is not in a module or has been allocated, or false
otherwise.
Also change core_kernel_data() back to the more precise _sdata condition
and document the function.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Hirokazu Takata <takata@linux-m32r.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Helge Deller <deller@gmx.de>
Cc: JamesE.J.Bottomley <jejb@parisc-linux.org>
Link: http://lkml.kernel.org/r/1305855298.1465.19.camel@gandalf.stny.rr.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
----
arch/alpha/kernel/vmlinux.lds.S | 1 +
arch/m32r/kernel/vmlinux.lds.S | 1 +
arch/m68k/kernel/vmlinux-std.lds | 2 ++
arch/m68k/kernel/vmlinux-sun3.lds | 1 +
arch/mips/kernel/vmlinux.lds.S | 1 +
arch/parisc/kernel/vmlinux.lds.S | 3 +++
kernel/extable.c | 12 +++++++++++-
7 files changed, 20 insertions(+), 1 deletion(-)
Merge reason: One pending commit was left in perf/core after Linus merged
perf/core - continue v2.6.40 work in the perf/urgent reason.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This change adds support for /proc/sys/debug/exception-trace to tile.
Like x86 and sparc, by default it is set to "1", generating a one-line
printk whenever a user process crashes. By setting it to "2", we get
a much more complete userspace diagnostic at crash time, including
a user-space backtrace, register dump, and memory dump around the
address of the crash.
Some vestiges of the Tilera-internal version of this support are
removed with this patch (the show_crashinfo variable and the
arch_coredump_signal function). We retain a "crashinfo" boot parameter
which allows you to set the boot-time value of exception-trace.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
* 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (44 commits)
debugfs: Silence DEBUG_STRICT_USER_COPY_CHECKS=y warning
sysfs: remove "last sysfs file:" line from the oops messages
drivers/base/memory.c: fix warning due to "memory hotplug: Speed up add/remove when blocks are larger than PAGES_PER_SECTION"
memory hotplug: Speed up add/remove when blocks are larger than PAGES_PER_SECTION
SYSFS: Fix erroneous comments for sysfs_update_group().
driver core: remove the driver-model structures from the documentation
driver core: Add the device driver-model structures to kerneldoc
Translated Documentation/email-clients.txt
RAW driver: Remove call to kobject_put().
reboot: disable usermodehelper to prevent fs access
efivars: prevent oops on unload when efi is not enabled
Allow setting of number of raw devices as a module parameter
Introduce CONFIG_GOOGLE_FIRMWARE
driver: Google Memory Console
driver: Google EFI SMI
x86: Better comments for get_bios_ebda()
x86: get_bios_ebda_length()
misc: fix ti-st build issues
params.c: Use new strtobool function to process boolean inputs
debugfs: move to new strtobool
...
Fix up trivial conflicts in fs/debugfs/file.c due to the same patch
being applied twice, and an unrelated cleanup nearby.
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
hrtimer: Make lookup table const
RTC: Disable CONFIG_RTC_CLASS from being built as a module
timers: Fix alarmtimer build issues when CONFIG_RTC_CLASS=n
timers: Remove delayed irqwork from alarmtimers implementation
timers: Improve alarmtimer comments and minor fixes
timers: Posix interface for alarm-timers
timers: Introduce in-kernel alarm-timer interface
timers: Add rb_init_node() to allow for stack allocated rb nodes
time: Add timekeeping_inject_sleeptime
* 'timers-clockevents-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: hpet: Cleanup the clockevents init and register code
x86: Convert PIT to clockevents_config_and_register()
clockevents: Provide interface to reconfigure an active clock event device
clockevents: Provide combined configure and register function
clockevents: Restructure clock_event_device members
clocksource: Get rid of the hardcoded 5 seconds sleep time limit
clocksource: Restructure clocksource struct members
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (60 commits)
sched: Fix and optimise calculation of the weight-inverse
sched: Avoid going ahead if ->cpus_allowed is not changed
sched, rt: Update rq clock when unthrottling of an otherwise idle CPU
sched: Remove unused parameters from sched_fork() and wake_up_new_task()
sched: Shorten the construction of the span cpu mask of sched domain
sched: Wrap the 'cfs_rq->nr_spread_over' field with CONFIG_SCHED_DEBUG
sched: Remove unused 'this_best_prio arg' from balance_tasks()
sched: Remove noop in alloc_rt_sched_group()
sched: Get rid of lock_depth
sched: Remove obsolete comment from scheduler_tick()
sched: Fix sched_domain iterations vs. RCU
sched: Next buddy hint on sleep and preempt path
sched: Make set_*_buddy() work on non-task entities
sched: Remove need_migrate_task()
sched: Move the second half of ttwu() to the remote cpu
sched: Restructure ttwu() some more
sched: Rename ttwu_post_activation() to ttwu_do_wakeup()
sched: Remove rq argument from ttwu_stat()
sched: Remove rq->lock from the first half of ttwu()
sched: Drop rq->lock from sched_exec()
...
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: Fix rt_rq runtime leakage bug
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (107 commits)
perf stat: Add more cache-miss percentage printouts
perf stat: Add -d -d and -d -d -d options to show more CPU events
ftrace/kbuild: Add recordmcount files to force full build
ftrace: Add self-tests for multiple function trace users
ftrace: Modify ftrace_set_filter/notrace to take ops
ftrace: Allow dynamically allocated function tracers
ftrace: Implement separate user function filtering
ftrace: Free hash with call_rcu_sched()
ftrace: Have global_ops store the functions that are to be traced
ftrace: Add ops parameter to ftrace_startup/shutdown functions
ftrace: Add enabled_functions file
ftrace: Use counters to enable functions to trace
ftrace: Separate hash allocation and assignment
ftrace: Create a global_ops to hold the filter and notrace hashes
ftrace: Use hash instead for FTRACE_FL_FILTER
ftrace: Replace FTRACE_FL_NOTRACE flag with a hash of ignored functions
perf bench, x86: Add alternatives-asm.h wrapper
x86, 64-bit: Fix copy_[to/from]_user() checks for the userspace address limit
x86, mem: memset_64.S: Optimize memset by enhanced REP MOVSB/STOSB
x86, mem: memmove_64.S: Optimize memmove by enhanced REP MOVSB/STOSB
...
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
seqlock: Don't smp_rmb in seqlock reader spin loop
watchdog, hung_task_timeout: Add Kconfig configurable default
lockdep: Remove cmpxchg to update nr_chain_hlocks
lockdep: Print a nicer description for simple irq lock inversions
lockdep: Replace "Bad BFS generated tree" message with something less cryptic
lockdep: Print a nicer description for irq inversion bugs
lockdep: Print a nicer description for simple deadlocks
lockdep: Print a nicer description for normal deadlocks
lockdep: Print a nicer description for irq lock inversions
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6: (34 commits)
PM: Introduce generic prepare and complete callbacks for subsystems
PM: Allow drivers to allocate memory from .prepare() callbacks safely
PM: Remove CONFIG_PM_VERBOSE
Revert "PM / Hibernate: Reduce autotuned default image size"
PM / Hibernate: Add sysfs knob to control size of memory for drivers
PM / Wakeup: Remove useless synchronize_rcu() call
kmod: always provide usermodehelper_disable()
PM / ACPI: Remove acpi_sleep=s4_nonvs
PM / Wakeup: Fix build warning related to the "wakeup" sysfs file
PM: Print a warning if firmware is requested when tasks are frozen
PM / Runtime: Rework runtime PM handling during driver removal
Freezer: Use SMP barriers
PM / Suspend: Do not ignore error codes returned by suspend_enter()
PM: Fix build issue in clock_ops.c for CONFIG_PM_RUNTIME unset
PM: Revert "driver core: platform_bus: allow runtime override of dev_pm_ops"
OMAP1 / PM: Use generic clock manipulation routines for runtime PM
PM: Remove sysdev suspend, resume and shutdown operations
PM / PowerPC: Use struct syscore_ops instead of sysdevs for PM
PM / UNICORE32: Use struct syscore_ops instead of sysdevs for PM
PM / AVR32: Use struct syscore_ops instead of sysdevs for PM
...
Some architectures such as Alpha do not define _sdata but _data:
kernel/built-in.o: In function `core_kernel_data':
kernel/extable.c:77: undefined reference to `_sdata'
So expand the scope of the data range to the text addresses too,
this might be more correct anyway because this way we can
cover readonly variables as well.
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-i878c8a0e0g0ep4v7i6vxnhz@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
move LSM-, credentials-, and keys-related files from Documentation/
to Documentation/security/,
add Documentation/security/00-INDEX, and
update all occurrences of Documentation/<moved_file>
to Documentation/security/<moved_file>.
This reverts commit e59fb3120b.
This reversion was due to (extreme) boot-time slowdowns on SPARC seen by
Yinghai Lu and on x86 by Ingo
.
This is a non-trivial reversion due to intervening commits.
Conflicts:
Documentation/RCU/trace.txt
kernel/rcutree.c
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Some ARM SoCs have clock event devices which have their frequency
modified due to frequency scaling. Provide an interface which allows
to reconfigure an active device. After reconfiguration reprogram the
current pending event.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: LAK <linux-arm-kernel@lists.infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Link: http://lkml.kernel.org/r/%3C20110518210136.437459958%40linutronix.de%3E
All clockevent devices have the same open coded initialization
functions. Provide an interface which does all necessary
initialization in the core code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Link: http://lkml.kernel.org/r/%3C20110518210136.331975870%40linutronix.de%3E
Slow clocksources can have a way longer sleep time than 5 seconds and
even fast ones can easily cope with 600 seconds and still maintain
proper accuracy.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Link: http://lkml.kernel.org/r/%3C20110518210136.109811585%40linutronix.de%3E
The function is_exported() with its helper function lookup_symbol() are used to
verify if a provided symbol is effectively exported by the kernel or by the
modules. Now that both have their symbols sorted we can replace a linear search
with a binary search which provide a considerably speed-up.
This work was supported by a hardware donation from the CE Linux Forum.
Signed-off-by: Alessio Igor Bogani <abogani@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Takes advantage of the order and locates symbols using binary search.
This work was supported by a hardware donation from the CE Linux Forum.
Signed-off-by: Alessio Igor Bogani <abogani@kernel.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Dirk Behme <dirk.behme@googlemail.com>
Instead of having a callback function for each symbol in the kernel,
have a callback for each array of symbols.
This eases the logic when we move to sorted symbols and binary search.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Alessio Igor Bogani <abogani@kernel.org>
Split the unprotect function into a function per section to make
the code more readable and add the missing static declaration.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
While debugging I stumbled over two problems in the code that protects module
pages.
First issue is that disabling the protection before freeing init or unload of
a module is not symmetric with the enablement. For instance, if pages are set
to RO the page range from module_core to module_core + core_ro_size is
protected. If a module is unloaded the page range from module_core to
module_core + core_size is set back to RW.
So pages that were not set to RO are also changed to RW.
This is not critical but IMHO it should be symmetric.
Second issue is that while set_memory_rw & set_memory_ro are used for
RO/RW changes only set_memory_nx is involved for NX/X. One would await that
the inverse function is called when the NX protection should be removed,
which is not the case here, unless I'm missing something.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reset mod->init_ro_size to zero after the init part of a module is unloaded.
Otherwise we need to check if module->init is NULL in the unprotect functions
in the next patch.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Fix function prototype to be ANSI-C compliant, consistent with other
function prototypes, addressing a sparse warning.
Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
On m68k natural alignment is 2-byte boundary but we are trying to
align structures in __modver section on sizeof(void *) boundary.
This causes trouble when we try to access elements in this section
in array-like fashion when create "version" attributes for built-in
modules.
Moreover, as DaveM said, we can't reliably put structures into
independent objects, put them into a special section, and then expect
array access over them (via the section boundaries) after linking the
objects together to just "work" due to variable alignment choices in
different situations. The only solution that seems to work reliably
is to make an array of plain pointers to the objects in question and
put those pointers in the special section.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Since users of the function tracer can now pick and choose which
functions they want to trace agnostically from other users of the
function tracer, we need to pass the ops struct to the ftrace_set_filter()
functions.
The functions ftrace_set_global_filter() and ftrace_set_global_notrace()
is added to keep the old filter functions which are used to modify
the generic function tracers.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Now that functions may be selected individually, it only makes sense
that we should allow dynamically allocated trace structures to
be traced. This will allow perf to allocate a ftrace_ops structure
at runtime and use it to pick and choose which functions that
structure will trace.
Note, a dynamically allocated ftrace_ops will always be called
indirectly instead of being called directly from the mcount in
entry.S. This is because there's no safe way to prevent mcount
from being preempted before calling the function, unless we
modify every entry.S to do so (not likely). Thus, dynamically allocated
functions will now be called by the ftrace_ops_list_func() that
loops through the ops that are allocated if there are more than
one op allocated at a time. This loop is protected with a
preempt_disable.
To determine if an ftrace_ops structure is allocated or not, a new
util function was added to the kernel/extable.c called
core_kernel_data(), which returns 1 if the address is between
_sdata and _edata.
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
ftrace_ops that are registered to trace functions can now be
agnostic to each other in respect to what functions they trace.
Each ops has their own hash of the functions they want to trace
and a hash to what they do not want to trace. A empty hash for
the functions they want to trace denotes all functions should
be traced that are not in the notrace hash.
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When a hash is modified and might be in use, we need to perform
a schedule RCU operation on it, as the hashes will soon be used
directly in the function tracer callback.
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This is a step towards each ops structure defining its own set
of functions to trace. As the current code with pid's and such
are specific to the global_ops, it is restructured to be used
with the global ops.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In order to allow different ops to enable different functions,
the ftrace_startup() and ftrace_shutdown() functions need the
ops parameter passed to them.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add the enabled_functions file that is used to show all the
functions that have been enabled for tracing as well as their
ref counts. This helps seeing if any function has been registered
and what functions are being traced.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Every function has its own record that stores the instruction
pointer and flags for the function to be traced. There are only
two flags: enabled and free. The enabled flag states that tracing
for the function has been enabled (actively traced), and the free
flag states that the record no longer points to a function and can
be used by new functions (loaded modules).
These flags are now moved to the MSB of the flags (actually just
the top 32bits). The rest of the bits (30 bits) are now used as
a ref counter. Everytime a tracer register functions to trace,
those functions will have its counter incremented.
When tracing is enabled, to determine if a function should be traced,
the counter is examined, and if it is non-zero it is set to trace.
When a ftrace_ops is registered to trace functions, its hashes
are examined. If the ftrace_ops filter_hash count is zero, then
all functions are set to be traced, otherwise only the functions
in the hash are to be traced. The exception to this is if a function
is also in the ftrace_ops notrace_hash. Then that function's counter
is not incremented for this ftrace_ops.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When filtering, allocate a hash to insert the function records.
After the filtering is complete, assign it to the ftrace_ops structure.
This allows the ftrace_ops structure to have a much smaller array of
hash buckets instead of wasting a lot of memory.
A read only empty_hash is created to be the minimum size that any ftrace_ops
can point to.
When a new hash is created, it has the following steps:
o Allocate a default hash.
o Walk the function records assigning the filtered records to the hash
o Allocate a new hash with the appropriate size buckets
o Move the entries from the default hash to the new hash.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Combine the filter and notrace hashes to be accessed by a single entity,
the global_ops. The global_ops is a ftrace_ops structure that is passed
to different functions that can read or modify the filtering of the
function tracer.
The ftrace_ops structure was modified to hold a filter and notrace
hashes so that later patches may allow each ftrace_ops to have its own
set of rules to what functions may be filtered.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When multiple users are allowed to have their own set of functions
to trace, having the FTRACE_FL_FILTER flag will not be enough to
handle the accounting of those users. Each user will need their own
set of functions.
Replace the FTRACE_FL_FILTER with a filter_hash instead. This is
temporary until the rest of the function filtering accounting
gets in.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
To prepare for the accounting system that will allow multiple users of
the function tracer, having the FTRACE_FL_NOTRACE as a flag in the
dyn_trace record does not make sense.
All ftrace_ops will soon have a hash of functions they should trace
and not trace. By making a global hash of functions not to trace makes
this easier for the transition.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Export handle_simple_irq, irq_modify_status, irq_alloc_descs,
irq_free_descs and generic_handle_irq to allow their usage in
modules. First user is IIO, which wants to be built modular, but needs
to be able to create irq chips, allocate and configure interrupt
descriptors and handle demultiplexing interrupts.
[ tglx: Moved the uninlinig of generic_handle_irq to a separate patch ]
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Link: http://lkml.kernel.org/r/%3C1305711544-505-1-git-send-email-jic23%40cam.ac.uk%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
generic_handle_irq() is missing a NULL pointer check for the result of
irq_to_desc. This was a not a big problem, but we want to expose it to
drivers, so we better have sanity checks in place. Add a return value
as well, which indicates that the irq number was valid and the handler
was invoked.
Based on the pure code move from Jonathan Cameron.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jonathan Cameron <jic23@cam.ac.uk>
kernel/irq/ is only built when CONFIG_GENERIC_HARDIRQS=y. So making
code inside of kernel/irq/ conditional on CONFIG_GENERIC_HARDIRQS is
pointless.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
If device drivers allocate substantial amounts of memory (above 1 MB)
in their hibernate .freeze() callbacks (or in their legacy suspend
callbcks during hibernation), the subsequent creation of hibernate
image may fail due to the lack of memory. This is the case, because
the drivers' .freeze() callbacks are executed after the hibernate
memory preallocation has been carried out and the preallocated amount
of memory may be too small to cover the new driver allocations.
Unfortunately, the drivers' .prepare() callbacks also are executed
after the hibernate memory preallocation has completed, so they are
not suitable for allocating additional memory either. Thus the only
way a driver can safely allocate memory during hibernation is to use
a hibernate/suspend notifier. However, the notifiers are called
before the freezing of user space and the drivers wanting to use them
for allocating additional memory may not know how much memory needs
to be allocated at that point.
To let device drivers overcome this difficulty rework the hibernation
sequence so that the memory preallocation is carried out after the
drivers' .prepare() callbacks have been executed, so that the
.prepare() callbacks can be used for allocating additional memory
to be used by the drivers' .freeze() callbacks. Update documentation
to match the new behavior of the code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Now that we have CONFIG_DYNAMIC_DEBUG there is no need for yet
another flag causing dev_dbg() and pr_debug() statements in the
core PM code to produce output. Moreover, CONFIG_PM_VERBOSE
causes so much output to be generated that it's not really useful
and almost no one sets it.
References: https://bugzilla.kernel.org/show_bug.cgi?id=23182
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* power-domains:
PM: Fix build issue in clock_ops.c for CONFIG_PM_RUNTIME unset
PM: Revert "driver core: platform_bus: allow runtime override of dev_pm_ops"
OMAP1 / PM: Use generic clock manipulation routines for runtime PM
PM / Runtime: Generic clock manipulation rountines for runtime PM (v6)
PM / Runtime: Add subsystem data field to struct dev_pm_info
OMAP2+ / PM: move runtime PM implementation to use device power domains
PM / Platform: Use generic runtime PM callbacks directly
shmobile: Use power domains for platform runtime PM
PM: Export platform bus type's default PM callbacks
PM: Make power domain callbacks take precedence over subsystem ones
* syscore:
PM: Remove sysdev suspend, resume and shutdown operations
PM / PowerPC: Use struct syscore_ops instead of sysdevs for PM
PM / UNICORE32: Use struct syscore_ops instead of sysdevs for PM
PM / AVR32: Use struct syscore_ops instead of sysdevs for PM
PM / Blackfin: Use struct syscore_ops instead of sysdevs for PM
ARM / Samsung: Use struct syscore_ops for "core" power management
ARM / PXA: Use struct syscore_ops for "core" power management
ARM / SA1100: Use struct syscore_ops for "core" power management
ARM / Integrator: Use struct syscore_ops for core PM
ARM / OMAP: Use struct syscore_ops for "core" power management
ARM: Use struct syscore_ops instead of sysdevs for PM in common code
This reverts commit bea3864fb6
(PM / Hibernate: Reduce autotuned default image size), because users
are now able to resolve the issue this commit was supposed to address
in a different way (i.e. by using the new /sys/power/reserved_size
interface).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Martin reports that on his system hibernation occasionally fails due
to the lack of memory, because the radeon driver apparently allocates
too much of it during the device freeze stage. It turns out that the
amount of memory allocated by radeon during hibernation (and
presumably during system suspend too) depends on the utilization of
the GPU (e.g. hibernating while there are two KDE 4 sessions with
compositing enabled causes radeon to allocate more memory than for
one KDE 4 session).
In principle it should be possible to use image_size to make the
memory preallocation mechanism free enough memory for the radeon
driver, but in practice it is not easy to guess the right value
because of the way the preallocation code uses image_size. For this
reason, it seems reasonable to allow users to control the amount of
memory reserved for driver allocations made after the hibernate
preallocation, which currently is constant and amounts to 1 MB.
Introduce a new sysfs file, /sys/power/reserved_size, whose value
will be used as the amount of memory to reserve for the
post-preallocation reservations made by device drivers, in bytes.
For backwards compatibility, set its default (and initial) value to
the currently used number (1 MB).
References: https://bugzilla.kernel.org/show_bug.cgi?id=34102
Reported-and-tested-by: Martin Steigerwald <Martin@Lichtvoll.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
We need to prevent kernel-forked processes during system poweroff.
Such processes try to access the filesystem whose disks we are
trying to shutdown at the same time. This causes delays and exceptions
in the storage drivers.
A follow-up patch will add these calls and need usermodehelper_disable()
also on systems without suspend support.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Some drivers erroneously use request_firmware() from their ->resume()
(or ->thaw(), or ->restore()) callbacks, which is not going to work
unless the firmware has been built in. This causes system resume to
stall until the firmware-loading timeout expires, which makes users
think that the resume has failed and reboot their machines
unnecessarily. For this reason, make _request_firmware() print a
warning and return immediately with error code if it has been called
when tasks are frozen and it's impossible to start any new usermode
helpers.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Reviewed-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
The freezer processes are dealing with multiple threads running
simultaneously, and on a UP system, the memory reads/writes do
not need barriers to keep things in sync. These are only needed
on SMP systems, so use SMP barriers instead.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
The current implementation of suspend-to-RAM returns 0 if there is an
error from suspend_enter(), because suspend_devices_and_enter() ignores
the return value from suspend_enter(). This patch addresses this issue
and properly keep the error return from suspend_enter() and let
suspend_devices_and_enter relay the error return.
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
The first cpu which switches from periodic to oneshot mode switches
also the broadcast device into oneshot mode. The broadcast device
serves as a backup for per cpu timers which stop in deeper
C-states. To avoid starvation of the cpus which might be in idle and
depend on broadcast mode it marks the other cpus as broadcast active
and sets the brodcast expiry value of those cpus to the next tick.
The oneshot mode broadcast bit for the other cpus is sticky and gets
only cleared when those cpus exit idle. If a cpu was not idle while
the bit got set in consequence the bit prevents that the broadcast
device is armed on behalf of that cpu when it enters idle for the
first time after it switched to oneshot mode.
In most cases that goes unnoticed as one of the other cpus has usually
a timer pending which keeps the broadcast device armed with a short
timeout. Now if the only cpu which has a short timer active has the
bit set then the broadcast device will not be armed on behalf of that
cpu and will fire way after the expected timer expiry. In the case of
Christians bug report it took ~145 seconds which is about half of the
wrap around time of HPET (the limit for that device) due to the fact
that all other cpus had no timers armed which expired before the 145
seconds timeframe.
The solution is simply to clear the broadcast active bit
unconditionally when a cpu switches to oneshot mode after the first
cpu switched the broadcast device over. It's not idle at that point
otherwise it would not be executing that code.
[ I fundamentally hate that broadcast crap. Why the heck thought some
folks that when going into deep idle it's a brilliant concept to
switch off the last device which brings the cpu back from that
state? ]
Thanks to Christian for providing all the valuable debug information!
Reported-and-tested-by: Christian Hoffmann <email@christianhoffmann.info>
Cc: John Stultz <johnstul@us.ibm.com>
Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1105161105170.3078%40ionos%3E
Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
If the inverse loadweight should be zero, function "calc_delta_mine"
calculates the inverse of "lw->weight" (in 32bit integer ops).
This calculation is actually a little bit impure (because it is
inverting something around "lw-weight"+1), especially when
"lw->weight" becomes smaller.
The correct inverse would be 1/lw->weight multiplied by
"WMULT_CONST" for fixcomma-scaling it into integers.
(So WMULT_CONST/lw->weight ...)
The old, impure algorithm took two divisions for inverting lw->weight,
the new, more exact one only takes one and an additional unlikely-if.
Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-0pz0wnyalr4tk4ln11xwumdx@git.kernel.org
[ This could explain some aritmetical issues for small shares but nothing
concrete has been reported yet so we are not confident enough to queue
this up in sched/urgent and for -stable backport. But if anyone finds
this commit and sees it to fix some badness then we can certainly
change our mind! ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If cpumask_equal(&p->cpus_allowed, new_mask) is true, seems
there is no reason to prevent set_cpus_allowed_ptr() return
directly.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110509140705.GA2219@zhy
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If an RT task is awakened while it's rt_rq is throttled, the time between
wakeup/enqueue and unthrottle/selection may be accounted as rt_time
if the CPU is idle. Set rq->skip_clock_update negative upon throttle
release to tell put_prev_task() that we need a clock update.
Reported-by: Thomas Giesel <skoe@directbox.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1304059010.7472.1.camel@marge.simson.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch is to fix the real-time scheduler bug reported at:
https://lkml.org/lkml/2011/4/26/13
That is, when running multiple real-time threads on every logical CPUs
and then turning off one CPU, the kernel will bug at function
__disable_runtime().
Function __disable_runtime() bugs and reports leakage of rt_rq runtime.
The root cause is __disable_runtime() assumes it iterates through all
the existing rt_rq's while walking rq->leaf_rt_rq_list, which actually
contains only runnable rt_rq's. This problem also applies to
__enable_runtime() and print_rt_stats().
The patch is based on above analysis, appears to fix the problem, but is
only lightly tested.
Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Cheng Xu <chengxu@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4DCE1F12.6040609@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If !CONFIG_USERNS, have current_user_ns() defined to (&init_user_ns).
Get rid of _current_user_ns. This requires nsown_capable() to be
defined in capability.c rather than as static inline in capability.h,
so do that.
Request_key needs init_user_ns defined at current_user_ns if
!CONFIG_USERNS, so forward-declare that in cred.h if !CONFIG_USERNS
at current_user_ns() define.
Compile-tested with and without CONFIG_USERNS.
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
[ This makes a huge performance difference for acl_permission_check(),
up to 30%. And that is one of the hottest kernel functions for loads
that are pathname-lookup heavy. ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
wait_task_stopped() tested task_stopped_code() without acquiring
siglock and, if stop condition existed, called wait_task_stopped() and
directly returned the result. This patch moves the initial
task_stopped_code() testing into wait_task_stopped() and make
wait_consider_task() fall through to wait_task_continue() on 0 return.
This is for the following two reasons.
* Because the initial task_stopped_code() test is done without
acquiring siglock, it may race against SIGCONT generation. The
stopped condition might have been replaced by continued state by the
time wait_task_stopped() acquired siglock. This may lead to
unexpected failure of WNOHANG waits.
This reorganization addresses this single race case but there are
other cases - TASK_RUNNING -> TASK_STOPPED transition and EXIT_*
transitions.
* Scheduled ptrace updates require changes to the initial test which
would fit better inside wait_task_stopped().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
The existing <asm-generic/unistd.h> mechanism doesn't really provide
enough to create the 64-bit "compat" ABI properly in a generic way,
since the compat ABI is a mix of things were you can re-use the 64-bit
versions of syscalls and things where you need a compat wrapper.
To provide this in the most direct way possible, I added two new macros
to go along with the existing __SYSCALL and __SC_3264 macros: __SC_COMP
and SC_COMP_3264. These macros take an additional argument, typically a
"compat_sys_xxx" function, which is passed to __SYSCALL if you define
__SYSCALL_COMPAT when including the header, resulting in a pointer to
the compat function being placed in the generated syscall table.
The change also adds some missing definitions to <linux/compat.h> so that
it actually has declarations for all the compat syscalls, since the
"[nr] = ##call" approach requires proper C declarations for all the
functions included in the syscall table.
Finally, compat.c defines compat_sys_sigpending() and
compat_sys_sigprocmask() even if the underlying architecture doesn't
request it, which tries to pull in undefined compat_old_sigset_t defines.
We need to guard those compat syscall definitions with appropriate
__ARCH_WANT_SYS_xxx ifdefs.
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
sched_fork() and wake_up_new_task() are defined with a parameter
'unsigned long clone_flags', which is unused.
This patch removes the parameters.
Signed-off-by: Samir Bellabes <sam@synack.fr>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1305130685-1047-1-git-send-email-sam@synack.fr
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since suspend, resume and shutdown operations in struct sysdev_class
and struct sysdev_driver are not used any more, remove them. Also
drop sysdev_suspend(), sysdev_resume() and sysdev_shutdown() used
for executing those operations and modify all of their users
accordingly. This reduces kernel code size quite a bit and reduces
its complexity.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
The SNAPSHOT_S2RAM ioctl used for implementing the feature allowing
one to suspend to RAM after creating a hibernation image is currently
broken, because it doesn't clear the "ready" flag in the struct
snapshot_data object handled by it. As a result, the
SNAPSHOT_UNFREEZE doesn't work correctly after SNAPSHOT_S2RAM has
returned and the user space hibernate task cannot thaw the other
processes as appropriate. Make SNAPSHOT_S2RAM clear data->ready
to fix this problem.
Tested-by: Alexandre Felipe Muller de Souza <alexandrefm@mandriva.com.br>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
If the process using the hibernate user space interface closes
/dev/snapshot after creating a hibernation image without thawing
tasks, snapshot_release() should call pm_restore_gfp_mask() to
restore the GFP mask used before the creation of the image. Make
that happen.
Tested-by: Alexandre Felipe Muller de Souza <alexandrefm@mandriva.com.br>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
A warning is printed by pm_restrict_gfp_mask() while the
SNAPSHOT_S2RAM ioctl is being executed after creating a hibernation
image, because pm_restrict_gfp_mask() has been called once already
before the image creation and suspend_devices_and_enter() calls it
once again. This happens after commit 452aa6999e
(mm/pm: force GFP_NOIO during suspend/hibernation and resume).
To avoid this issue, move pm_restrict_gfp_mask() and
pm_restore_gfp_mask() from suspend_devices_and_enter() to its caller
in kernel/power/suspend.c.
Reported-by: Alexandre Felipe Muller de Souza <alexandrefm@mandriva.com.br>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
With the networking stack today there is demand to handle
multiple network stacks at a time. Not in the context
of containers but in the context of people doing interesting
things with routing.
There is also demand in the context of containers to have
an efficient way to execute some code in the container itself.
If nothing else it is very useful ad a debugging technique.
Both problems can be solved by starting some form of login
daemon in the namespaces people want access to, or you
can play games by ptracing a process and getting the
traced process to do things you want it to do. However
it turns out that a login daemon or a ptrace puppet
controller are more code, they are more prone to
failure, and generally they are less efficient than
simply changing the namespace of a process to a
specified one.
Pieces of this puzzle can also be solved by instead of
coming up with a general purpose system call coming up
with targed system calls perhaps socketat that solve
a subset of the larger problem. Overall that appears
to be more work for less reward.
int setns(int fd, int nstype);
The fd argument is a file descriptor referring to a proc
file of the namespace you want to switch the process to.
In the setns system call the nstype is 0 or specifies
an clone flag of the namespace you intend to change
to prevent changing a namespace unintentionally.
v2: Most of the architecture support added by Daniel Lezcano <dlezcano@fr.ibm.com>
v3: ported to v2.6.36-rc4 by: Eric W. Biederman <ebiederm@xmission.com>
v4: Moved wiring up of the system call to another patch
v5: Cleaned up the system call arguments
- Changed the order.
- Modified nstype to take the standard clone flags.
v6: Added missing error handling as pointed out by Matt Helsley <matthltc@us.ibm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
The rcu callback swevent_hlist_release_rcu() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(swevent_hlist_release_rcu).
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The rcu callback free_ctx() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(free_ctx).
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The rcu callback __free_css_id_cb() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(__free_css_id_cb).
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The rcu callback free_cgroup_rcu() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(free_cgroup_rcu).
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The rcu callback free_css_set_rcu() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(free_css_set_rcu).
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Avoid calling into the scheduler while holding core RCU locks. This
allows rcu_read_unlock() to be called while holding the runqueue locks,
but only as long as there was no chance of the RCU read-side critical
section having been preempted. (Otherwise, if RCU priority boosting
is enabled, rcu_read_unlock() might call into the scheduler in order to
unboost itself, which might allows self-deadlock on the runqueue locks
within the scheduler.)
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
In case CONFIG_UEVENT_HELPER_PATH is not set to "", which it
should be on every system, the kernel forks processes during
shutdown, which try to access the rootfs, even when the
binary does not exist. It causes exceptions and long delays in
the disk driver, which gets read requests at the time it tries
to shut down the disk.
This patch disables all kernel-forked processes during reboot to
allow a clean poweroff.
Cc: Tejun Heo <htejun@gmail.com>
Tested-By: Anton Guda <atu@dmeti.dp.ua>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This partially reverts commit e6e1e25935.
That commit changed the structure layout of the trace structure, which
in turn broke PowerTOP (1.9x generation) quite badly.
I appreciate not wanting to expose the variable in question, and
PowerTOP was not using it, so I've replaced the variable with just a
padding field - that way if in the future a new field is needed it can
just use this padding field.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For a given node, when constructing the cpumask for its
sched_domain to span, if there is no best node available after
searching, further efforts could be saved, based on small change
in the return value of find_next_best_node().
Signed-off-by: Hillf Danton <dhillf@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Yong Zhang <yong.zhang0@gmail.com>
Link: http://lkml.kernel.org/r/BANLkTi%3DqPWxRAa6%2BdT3ohEP6Z%3D0v%2Be4EXA@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
cfs_rq->nr_spread_over is only used when CONFIG_SCHED_DEBUG is set.
So wrap it with CONFIG_SCHED_DEBUG.
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1304528026.15681.3.camel@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Provide rcu_virt_note_context_switch() for vitalization use to note
quiescent state during guest entry.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
rcu_sched_qs() currently calls local_irq_save()/local_irq_restore() up
to three times.
Remove irq masking from rcu_qsctr_help() / invoke_rcu_kthread()
and do it once in rcu_sched_qs() / rcu_bh_qs()
This generates smaller code as well.
text data bss dec hex filename
2314 156 24 2494 9be kernel/rcutiny.old.o
2250 156 24 2430 97e kernel/rcutiny.new.o
Fix an outdated comment for rcu_qsctr_help()
Move invoke_rcu_kthread() definition before its use.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit marks a first step towards making call_rcu() have
real-time behavior. If irqs are disabled, don't dive into the
RCU core. Later on, this new early exit will wake up the
per-CPU kthread, which first must be modified to handle the
cases involving callback storms.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Although rcu_yield() dropped from real-time to normal priority, there
is always the possibility that the competing tasks have been niced.
So nice to 19 in rcu_yield() to help ensure that other tasks have a
better chance of running.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Many rcu callbacks functions just call kfree() on the base structure.
These functions are trivial, but their size adds up, and furthermore
when they are used in a kernel module, that module must invoke the
high-latency rcu_barrier() function at module-unload time.
The kfree_rcu() function introduced by this commit addresses this issue.
Rather than encoding a function address in the embedded rcu_head
structure, kfree_rcu() instead encodes the offset of the rcu_head
structure within the base structure. Because the functions are not
allowed in the low-order 4096 bytes of kernel virtual memory, offsets
up to 4095 bytes can be accommodated. If the offset is larger than
4095 bytes, a compile-time error will be generated in __kfree_rcu().
If this error is triggered, you can either fall back to use of call_rcu()
or rearrange the structure to position the rcu_head structure into the
first 4096 bytes.
Note that the allowable offset might decrease in the future, for example,
to allow something like kmem_cache_free_rcu().
The new kfree_rcu() function can replace code as follows:
call_rcu(&p->rcu, simple_kfree_callback);
where "simple_kfree_callback()" might be defined as follows:
void simple_kfree_callback(struct rcu_head *p)
{
struct foo *q = container_of(p, struct foo, rcu);
kfree(q);
}
with the following:
kfree_rcu(&p->rcu, rcu);
Note that the "rcu" is the name of a field in the structure being
freed. The reason for using this rather than passing in a pointer
to the base structure is that the above approach allows better type
checking.
This commit is based on earlier work by Lai Jiangshan and Manfred Spraul:
Lai's V1 patch: http://lkml.org/lkml/2008/9/18/1
Manfred's patch: http://lkml.org/lkml/2009/1/2/115
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The "preemptible" spelling is preferable. May as well fix it.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Using __rcu_read_lock() in place of rcu_read_lock() leaves any debug
state as it really should be, namely with the lock still held.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This applies a trick from TREE_RCU boosting to TINY_RCU, eliminating
code and adding comments. The key point is that it is possible for
the booster thread itself to work out whether there is a normal or
expedited boost required based solely on local information. There
is therefore no need for boost initiation to know or care what type
of boosting is required. In addition, when boosting is complete for
a given grace period, then by definition there cannot be any more
boosting for that grace period. This allows eliminating yet more
state and statistics.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The ->boosted_this_gp field is a holdover from an earlier design that
was to carry out multiple boost operations in parallel. It is not required
by the current design, which boosts one task at a time.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Extraneous semicolon, bad comment, and fold INIT_LIST_HEAD() into
list_del() to get list_del_init().
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This removes a couple of lines from invoke_rcu_cpu_kthread(), improving
readability.
Reported-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The CONFIG_DEBUG_OBJECTS_RCU_HEAD facility requires that on-stack RCU
callbacks be flagged explicitly to debug-objects using the
init_rcu_head_on_stack() and destroy_rcu_head_on_stack() functions.
This commit applies those functions to the rcutorture code that tests
RCU priority boosting.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The prohibition of DEBUG_OBJECTS_RCU_HEAD from !PREEMPT was due to the
fixup actions. So just produce a warning from !PREEMPT.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Increment a per-CPU counter on each pass through rcu_cpu_kthread()'s
service loop, and add it to the rcudata trace output.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit adds the age in jiffies of the current grace period along
with the duration in jiffies of the longest grace period since boot
to the rcu/rcugp debugfs file. It also adds an additional "O" state
to kthread tracing to differentiate between the kthread waiting due to
having nothing to do on the one hand and waiting due to being on the
wrong CPU on the other hand.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_initiate_boost_trace() function mis-attributed refusals to
initiate RCU priority boosting that were in fact due to its not yet
being time to boost. This patch fixes the faulty comparison.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
It is not possible to accurately correlate rcutorture output with that
of debugfs. This patch therefore adds a debugfs file that prints out
the rcutorture version number, permitting easy correlation.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Add tracing to help debugging situations when RCU's kthreads are not
running but are supposed to be.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit adds an indication of the state of the callback queue using
a string of four characters following the "ql=" integer queue length.
The first character is "N" if there are callbacks that have been
queued that are not yet ready to be handled by the next grace period, or
"." otherwise. The second character is "R" if there are callbacks queued
that are ready to be handled by the next grace period, or "." otherwise.
The third character is "W" if there are callbacks waiting for the current
grace period, or "." otherwise. Finally, the fourth character is "D"
if there are callbacks that have been handled by a prior grace period
and are waiting to be invoked, or ".".
Note that callbacks that are in the process of being invoked are
not shown. These callbacks would have been removed from the rcu_data
structure's list by rcu_do_batch() prior to being executed. (These
callbacks are also not reflected in the "ql=" total, FWIW.)
Also, document the new callback-queue trace information.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Includes total number of tasks boosted, number boosted on behalf of each
of normal and expedited grace periods, and statistics on attempts to
initiate boosting that failed for various reasons.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The n_rcu_torture_boost_allocerror and n_rcu_torture_boost_afferror
statistics are not actually incremented anymore, so eliminate them.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The scheduler does not appear to take kindly to having multiple
real-time threads bound to a CPU that is going offline. So this
commit is a temporary hack-around to avoid that happening.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
If you are doing CPU hotplug operations, it is best not to have
CPU-bound realtime tasks running CPU-bound on the outgoing CPU.
So this commit makes per-CPU kthreads run at non-realtime priority
during that time.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The scheduler has had some heartburn in the past when too many real-time
kthreads were affinitied to the outgoing CPU. So, this commit lightens
the load by forcing the per-rcu_node and the boost kthreads off of the
outgoing CPU. Note that RCU's per-CPU kthread remains on the outgoing
CPU until the bitter end, as it must in order to preserve correctness.
Also avoid disabling hardirqs across calls to set_cpus_allowed_ptr(),
given that this function can block.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add priority boosting for TREE_PREEMPT_RCU, similar to that for
TINY_PREEMPT_RCU. This is enabled by the default-off RCU_BOOST
kernel parameter. The priority to which to boost preempted
RCU readers is controlled by the RCU_BOOST_PRIO kernel parameter
(defaulting to real-time priority 1) and the time to wait before
boosting the readers who are blocking a given grace period is
controlled by the RCU_BOOST_DELAY kernel parameter (defaulting to
500 milliseconds).
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
If RCU priority boosting is to be meaningful, callback invocation must
be boosted in addition to preempted RCU readers. Otherwise, in presence
of CPU real-time threads, the grace period ends, but the callbacks don't
get invoked. If the callbacks don't get invoked, the associated memory
doesn't get freed, so the system is still subject to OOM.
But it is not reasonable to priority-boost RCU_SOFTIRQ, so this commit
moves the callback invocations to a kthread, which can be boosted easily.
Also add comments and properly synchronized all accesses to
rcu_cpu_kthread_task, as suggested by Lai Jiangshan.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Combine the current TREE_PREEMPT_RCU ->blocked_tasks[] lists in the
rcu_node structure into a single ->blkd_tasks list with ->gp_tasks
and ->exp_tasks tail pointers. This is in preparation for RCU priority
boosting, which will add a third dimension to the combinatorial explosion
in the ->blocked_tasks[] case, but simply a third pointer in the new
->blkd_tasks case.
Also update documentation to reflect blocked_tasks[] merge
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Commit d09b62d fixed grace-period synchronization, but left some smp_mb()
invocations in rcu_process_callbacks() that are no longer needed, but
sheer paranoia prevented them from being removed. This commit removes
them and provides a proof of correctness in their absence. It also adds
a memory barrier to rcu_report_qs_rsp() immediately before the update to
rsp->completed in order to handle the theoretical possibility that the
compiler or CPU might move massive quantities of code into a lock-based
critical section. This also proves that the sheer paranoia was not
entirely unjustified, at least from a theoretical point of view.
In addition, the old dyntick-idle synchronization depended on the fact
that grace periods were many milliseconds in duration, so that it could
be assumed that no dyntick-idle CPU could reorder a memory reference
across an entire grace period. Unfortunately for this design, the
addition of expedited grace periods breaks this assumption, which has
the unfortunate side-effect of requiring atomic operations in the
functions that track dyntick-idle state for RCU. (There is some hope
that the algorithms used in user-level RCU might be applied here, but
some work is required to handle the NMIs that user-space applications
can happily ignore. For the short term, better safe than sorry.)
This proof assumes that neither compiler nor CPU will allow a lock
acquisition and release to be reordered, as doing so can result in
deadlock. The proof is as follows:
1. A given CPU declares a quiescent state under the protection of
its leaf rcu_node's lock.
2. If there is more than one level of rcu_node hierarchy, the
last CPU to declare a quiescent state will also acquire the
->lock of the next rcu_node up in the hierarchy, but only
after releasing the lower level's lock. The acquisition of this
lock clearly cannot occur prior to the acquisition of the leaf
node's lock.
3. Step 2 repeats until we reach the root rcu_node structure.
Please note again that only one lock is held at a time through
this process. The acquisition of the root rcu_node's ->lock
must occur after the release of that of the leaf rcu_node.
4. At this point, we set the ->completed field in the rcu_state
structure in rcu_report_qs_rsp(). However, if the rcu_node
hierarchy contains only one rcu_node, then in theory the code
preceding the quiescent state could leak into the critical
section. We therefore precede the update of ->completed with a
memory barrier. All CPUs will therefore agree that any updates
preceding any report of a quiescent state will have happened
before the update of ->completed.
5. Regardless of whether a new grace period is needed, rcu_start_gp()
will propagate the new value of ->completed to all of the leaf
rcu_node structures, under the protection of each rcu_node's ->lock.
If a new grace period is needed immediately, this propagation
will occur in the same critical section that ->completed was
set in, but courtesy of the memory barrier in #4 above, is still
seen to follow any pre-quiescent-state activity.
6. When a given CPU invokes __rcu_process_gp_end(), it becomes
aware of the end of the old grace period and therefore makes
any RCU callbacks that were waiting on that grace period eligible
for invocation.
If this CPU is the same one that detected the end of the grace
period, and if there is but a single rcu_node in the hierarchy,
we will still be in the single critical section. In this case,
the memory barrier in step #4 guarantees that all callbacks will
be seen to execute after each CPU's quiescent state.
On the other hand, if this is a different CPU, it will acquire
the leaf rcu_node's ->lock, and will again be serialized after
each CPU's quiescent state for the old grace period.
On the strength of this proof, this commit therefore removes the memory
barriers from rcu_process_callbacks() and adds one to rcu_report_qs_rsp().
The effect is to reduce the number of memory barriers by one and to
reduce the frequency of execution from about once per scheduling tick
per CPU to once per grace period.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The RCU CPU stall warnings can now be controlled using the
rcu_cpu_stall_suppress boot-time parameter or via the same parameter
from sysfs. There is therefore no longer any reason to have
kernel config parameters for this feature. This commit therefore
removes the RCU_CPU_STALL_DETECTOR and RCU_CPU_STALL_DETECTOR_RUNNABLE
kernel config parameters. The RCU_CPU_STALL_TIMEOUT parameter remains
to allow the timeout to be tuned and the RCU_CPU_STALL_VERBOSE parameter
remains to allow task-stall information to be suppressed if desired.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This patch adds a multiple message send syscall and is the send
version of the existing recvmmsg syscall. This is heavily
based on the patch by Arnaldo that added recvmmsg.
I wrote a microbenchmark to test the performance gains of using
this new syscall:
http://ozlabs.org/~anton/junkcode/sendmmsg_test.c
The test was run on a ppc64 box with a 10 Gbit network card. The
benchmark can send both UDP and RAW ethernet packets.
64B UDP
batch pkts/sec
1 804570
2 872800 (+ 8 %)
4 916556 (+14 %)
8 939712 (+17 %)
16 952688 (+18 %)
32 956448 (+19 %)
64 964800 (+20 %)
64B raw socket
batch pkts/sec
1 1201449
2 1350028 (+12 %)
4 1461416 (+22 %)
8 1513080 (+26 %)
16 1541216 (+28 %)
32 1553440 (+29 %)
64 1557888 (+30 %)
We see a 20% improvement in throughput on UDP send and 30%
on raw socket send.
[ Add sparc syscall entries. -DaveM ]
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Avoid taking broadcast_lock in the idle path for systems where the
timer doesn't stop in C3.
[ tglx: Removed the stale label and added comment ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Dave Kleikamp <dkleikamp@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: lenb@kernel.org
Cc: paulmck@us.ibm.com
Link: http://lkml.kernel.org/r/%3C20110504234806.GF2925%40one.firstfloor.org%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Christian Hoffmann reported that the command line clocksource override
with acpi_pm timer fails:
Kernel command line: <SNIP> clocksource=acpi_pm
hpet clockevent registered
Switching to clocksource hpet
Override clocksource acpi_pm is not HRT compatible.
Cannot switch while in HRT/NOHZ mode.
The watchdog code is what enables CLOCK_SOURCE_VALID_FOR_HRES, but we
actually end up selecting the clocksource before we enqueue it into
the watchdog list, so that's why we see the warning and fail to switch
to acpi_pm timer as requested. That's particularly bad when we want to
debug timekeeping related problems in early boot.
Put the selection call last.
Reported-by: Christian Hoffmann <email@christianhoffmann.info>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: stable@kernel.org # 32...
Link: http://lkml.kernel.org/r/%3C1304558210.2943.24.camel%40work-vm%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
class_find_device() takes a refcount on the rtc device. rtc_open()
takes another one, so we can drop it after the rtc_open() call.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
alarmtimer_late_init() uses class_find_device() to find a alarm
capable rtc device. The match callback stores a pointer to the name in
the char pointer handed in from the call site. alarmtimer_late_init()
checks the char pointer for NULL, but the pointer is on the stack and
not initialized to NULL before the call. So it can have random content
when the match function did not identify a device, which leads to
random access in the following rtc_open() call where the pointer is
dereferenced
Instead of relying on the char pointer, check the return value of
class_find_device. If a device is found then the name pointer is valid
as well.
Reported-by: Ingo Molnar <mingo@elte.hu>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
As part of the events sybsystem unification, relocate hw_breakpoint.c
into its new destination.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
mv kernel/perf_event.c -> kernel/events/core.c. From there, all further
sensible splitting can happen. The idea is that due to perf_event.c
becoming pretty sizable and with the advent of the marriage with ftrace,
splitting functionality into its logical parts should help speeding up
the unification and to manage the complexity of the subsystem.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Some applications must be aware of clock realtime being set
backward. A simple example is a clock applet which arms a timer for
the next minute display. If clock realtime is set backward then the
applet displays a stale time for the amount of time which the clock
was set backwards. Due to that applications poll the time because we
don't have an interface.
Extend the timerfd interface by adding a flag which puts the timer
onto a different internal realtime clock. All timers on this clock are
expired whenever the clock was set.
The timerfd core records the monotonic offset when the timer is
created. When the timer is armed, then the current offset is compared
to the previous recorded offset. When it has changed, then
timerfd_settime returns -ECANCELED. When a timer is read the offset is
compared and if it changed -ECANCELED returned to user space. Periodic
timers are not rearmed in the cancelation case.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Chris Friesen <chris.friesen@genband.com>
Tested-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Reviewed-by: Alexander Shishkin <virtuoso@slind.org>
Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1104271359580.3323%40ionos%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Make clock_was_set() unconditional and rename hres_timers_resume to
hrtimers_resume. This is a preparatory patch for hrtimers which are
cancelled when clock realtime was set.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Ingo pointed out that the alarmtimers won't build if CONFIG_RTC_CLASS=n.
This patch adds proper ifdefs to the alarmtimer code to disable the rtc
usage if it is not built in.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
commit ab7798ffcf ("genirq: Expand generic
show_interrupts()") added the Kconfig option GENERIC_IRQ_SHOW_LEVEL to
accomodate PowerPC, but this doesn't actually enable the functionality due
to a typo in the #ifdef check.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linux/PPC Development <linuxppc-dev@lists.ozlabs.org>
Link: http://lkml.kernel.org/r/%3Calpine.DEB.2.00.1104302251370.19068%40ayla.of.borg%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* 'fixes-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: fix deadlock in worker_maybe_bind_and_lock()
workqueue: Document debugging tricks
Fix up trivial spelling conflict in kernel/workqueue.c
The code used for matching functions is almost identical between normal
selecting of functions and using the :mod: feature of set_ftrace_notrace.
Consolidate the two users into one function.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There are three locations that perform almost identical functions in order
to update the ftrace_trace_function (the ftrace function variable that gets
called by mcount).
Consolidate these into a single function called update_ftrace_function().
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The updating of a function record is moved to a single function. This will allow
us to add specific changes in one location for both modules and kernel
functions.
Later patches will determine if the function record itself needs to be updated
(which enables the mcount caller), or just the ftrace_ops needs the update.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Since we disable all function tracer processing if we detect
that a modification of a instruction had failed, we do not need
to track that the record has failed. No more ftrace processing
is allowed, and the FTRACE_FL_CONVERTED flag is pointless.
The FTRACE_FL_CONVERTED flag was used to denote records that were
successfully converted from mcount calls into nops. But if a single
record fails, all of ftrace is disabled.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Since we disable all function tracer processing if we detect
that a modification of a instruction had failed, we do not need
to track that the record has failed. No more ftrace processing
is allowed, and the FTRACE_FL_FAILED flag is pointless.
Removing this flag simplifies some of the code, but some ftrace_disabled
checks needed to be added or move around a little.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The failures file in the debugfs tracing directory would list the
functions that failed to convert when the old dead ftrace daemon
tried to update code but failed. Since this code is now dead along
with the daemon the failures file is useless. Remove it.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The disabling of interrupts around ftrace_update_code() was used
to protect against the evil ftrace daemon from years past. But that
daemon has long been killed. It is safe to keep interrupts enabled
while updating the initial mcount into nops.
The ftrace_mutex is also held which keeps other users at bay.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Let FTRACE_WARN_ON() be used as a stand alone statement or
inside a conditional: if (FTRACE_WARN_ON(x))
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If function tracing is enabled, a read of the filter files will
cause the call to stop_machine to update the function trace sites.
It should only call stop_machine on write.
Cc: stable@kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Many different platforms and subsystems may want to disable device
clocks during suspend and enable them during resume which is going to
be done in a very similar way in all those cases. For this reason,
provide generic routines for the manipulation of device clocks during
suspend and resume.
Convert the ARM shmobile platform to using the new routines.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf, x86, nmi: Move LVT un-masking into irq handlers
perf events, x86: Work around the Nehalem AAJ80 erratum
perf, x86: Fix BTS condition
ftrace: Build without frame pointers on Microblaze
