Daniel Borkmann says:
====================
pull-request: bpf-next 2022-10-03
We've added 143 non-merge commits during the last 27 day(s) which contain
a total of 151 files changed, 8321 insertions(+), 1402 deletions(-).
The main changes are:
1) Add kfuncs for PKCS#7 signature verification from BPF programs, from Roberto Sassu.
2) Add support for struct-based arguments for trampoline based BPF programs,
from Yonghong Song.
3) Fix entry IP for kprobe-multi and trampoline probes under IBT enabled, from Jiri Olsa.
4) Batch of improvements to veristat selftest tool in particular to add CSV output,
a comparison mode for CSV outputs and filtering, from Andrii Nakryiko.
5) Add preparatory changes needed for the BPF core for upcoming BPF HID support,
from Benjamin Tissoires.
6) Support for direct writes to nf_conn's mark field from tc and XDP BPF program
types, from Daniel Xu.
7) Initial batch of documentation improvements for BPF insn set spec, from Dave Thaler.
8) Add a new BPF_MAP_TYPE_USER_RINGBUF map which provides single-user-space-producer /
single-kernel-consumer semantics for BPF ring buffer, from David Vernet.
9) Follow-up fixes to BPF allocator under RT to always use raw spinlock for the BPF
hashtab's bucket lock, from Hou Tao.
10) Allow creating an iterator that loops through only the resources of one
task/thread instead of all, from Kui-Feng Lee.
11) Add support for kptrs in the per-CPU arraymap, from Kumar Kartikeya Dwivedi.
12) Add a new kfunc helper for nf to set src/dst NAT IP/port in a newly allocated CT
entry which is not yet inserted, from Lorenzo Bianconi.
13) Remove invalid recursion check for struct_ops for TCP congestion control BPF
programs, from Martin KaFai Lau.
14) Fix W^X issue with BPF trampoline and BPF dispatcher, from Song Liu.
15) Fix percpu_counter leakage in BPF hashtab allocation error path, from Tetsuo Handa.
16) Various cleanups in BPF selftests to use preferred ASSERT_* macros, from Wang Yufen.
17) Add invocation for cgroup/connect{4,6} BPF programs for ICMP pings, from YiFei Zhu.
18) Lift blinding decision under bpf_jit_harden = 1 to bpf_capable(), from Yauheni Kaliuta.
19) Various libbpf fixes and cleanups including a libbpf NULL pointer deref, from Xin Liu.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (143 commits)
net: netfilter: move bpf_ct_set_nat_info kfunc in nf_nat_bpf.c
Documentation: bpf: Add implementation notes documentations to table of contents
bpf, docs: Delete misformatted table.
selftests/xsk: Fix double free
bpftool: Fix error message of strerror
libbpf: Fix overrun in netlink attribute iteration
selftests/bpf: Fix spelling mistake "unpriviledged" -> "unprivileged"
samples/bpf: Fix typo in xdp_router_ipv4 sample
bpftool: Remove unused struct event_ring_info
bpftool: Remove unused struct btf_attach_point
bpf, docs: Add TOC and fix formatting.
bpf, docs: Add Clang note about BPF_ALU
bpf, docs: Move Clang notes to a separate file
bpf, docs: Linux byteswap note
bpf, docs: Move legacy packet instructions to a separate file
selftests/bpf: Check -EBUSY for the recurred bpf_setsockopt(TCP_CONGESTION)
bpf: tcp: Stop bpf_setsockopt(TCP_CONGESTION) in init ops to recur itself
bpf: Refactor bpf_setsockopt(TCP_CONGESTION) handling into another function
bpf: Move the "cdg" tcp-cc check to the common sol_tcp_sockopt()
bpf: Add __bpf_prog_{enter,exit}_struct_ops for struct_ops trampoline
...
====================
Link: https://lore.kernel.org/r/20221003194915.11847-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Merge cpufreq changes for 6.1-rc1:
- Add isupport for Tiger Lake in no-HWP mode to intel_pstate (Doug
Smythies).
- Update the AMD P-state driver (Perry Yuan):
* Fix wrong lowest perf fetch.
* Map desired perf into pstate scope for powersave governor.
* Update pstate frequency transition delay time.
* Fix initial highest_perf value.
* Clean up.
- Move max CPU capacity to sugov_policy in the schedutil cpufreq
governor (Lukasz Luba).
- Add SM6115 to cpufreq-dt blocklist (Adam Skladowski).
- Add support for Tegra239 and minor cleanups (Sumit Gupta, ye xingchen,
and Yang Yingliang).
- Add freq qos for qcom cpufreq driver and minor cleanups (Xuewen Yan,
and Viresh Kumar).
- Minor cleanups around functions called at module_init() (Xiu Jianfeng).
- Use module_init and add module_exit for bmips driver (Zhang Jianhua).
* pm-cpufreq:
cpufreq: qcom-cpufreq-hw: Add cpufreq qos for LMh
cpufreq: Add __init annotation to module init funcs
cpufreq: tegra194: change tegra239_cpufreq_soc to static
cpufreq: tegra194: Add support for Tegra239
cpufreq: qcom-cpufreq-hw: Fix uninitialized throttled_freq warning
cpufreq: intel_pstate: Add Tigerlake support in no-HWP mode
cpufreq: amd-pstate: Fix initial highest_perf value
cpufreq: tegra194: Remove the unneeded result variable
cpufreq: amd-pstate: update pstate frequency transition delay time
cpufreq: amd_pstate: map desired perf into pstate scope for powersave governor
cpufreq: amd_pstate: fix wrong lowest perf fetch
cpufreq: amd-pstate: fix white-space
cpufreq: amd-pstate: simplify cpudata pointer assignment
cpufreq: bmips-cpufreq: Use module_init and add module_exit
cpufreq: schedutil: Move max CPU capacity to sugov_policy
cpufreq: Add SM6115 to cpufreq-dt-platdev blocklist
In order to enable namespaces or any sort of isolation within
user_events the register lock and pages need to be broken up into
groups. Each event and file now has a group pointer which stores the
actual pages to map, lookup data and synchronization objects.
This only enables a single group that maps to init_user_ns, as IMA
namespace has done. This enables user_events to start the work of
supporting namespaces by walking the namespaces up to the init_user_ns.
Future patches will address other user namespaces and will align to the
approaches the IMA namespace uses.
Link: https://lore.kernel.org/linux-kernel/20220915193221.1728029-15-stefanb@linux.ibm.com/#t
Link: https://lkml.kernel.org/r/20221001001016.2832-2-beaub@linux.microsoft.com
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This pull request contains the following branches:
doc.2022.08.31b: Documentation updates. This is the first in a series
from an ongoing review of the RCU documentation. "Why are people
thinking -that- about RCU? Oh. Because that is an entirely
reasonable interpretation of its documentation."
fixes.2022.08.31b: Miscellaneous fixes.
kvfree.2022.08.31b: Improved memory allocation and heuristics.
nocb.2022.09.01a: Improve rcu_nocbs diagnostic output.
poll.2022.08.31b: Add full-sized polled RCU grace period state values.
These are the same size as an rcu_head structure, which is double
that of the traditional unsigned long state values that may still
be obtained from et_state_synchronize_rcu(). The added size
avoids missing overlapping grace periods. This benefit is that
call_rcu() can be replaced by polling, which can be attractive
in situations where RCU-protected data is aged out of memory.
Early in the series, the size of this state value is three
unsigned longs. Later in the series, the synchronize_rcu() and
synchronize_rcu_expedited() fastpaths are reworked to permit
the full state to be represented by only two unsigned longs.
This reworking slows these two functions down in SMP kernels
running either on single-CPU systems or on systems with all but
one CPU offlined, but this should not be a significant problem.
And if it somehow becomes a problem in some yet-as-unforeseen
situations, three-value state values can be provided for only
those situations.
Finally, a pair of functions named same_state_synchronize_rcu()
and same_state_synchronize_rcu_full() allow grace-period state
values to be compared for equality. This permits users to
maintain lists of data structures having the same state value,
removing the need for per-data-structure grace-period state
values, thus decreasing memory footprint.
poll-srcu.2022.08.31b: Polled SRCU grace-period updates, including
adding tests to rcutorture and reducing the incidence of Tiny
SRCU grace-period-state counter wrap.
tasks.2022.08.31b: Improve Tasks RCU diagnostics and quiescent-state
detection.
-----BEGIN PGP SIGNATURE-----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=AZPZ
-----END PGP SIGNATURE-----
Merge tag 'rcu.2022.09.30a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu
Pull RCU updates from Paul McKenney:
- Documentation updates.
This is the first in a series from an ongoing review of the RCU
documentation. "Why are people thinking -that- about RCU? Oh. Because
that is an entirely reasonable interpretation of its documentation."
- Miscellaneous fixes.
- Improved memory allocation and heuristics.
- Improve rcu_nocbs diagnostic output.
- Add full-sized polled RCU grace period state values.
These are the same size as an rcu_head structure, which is double
that of the traditional unsigned long state values that may still be
obtained from et_state_synchronize_rcu(). The added size avoids
missing overlapping grace periods. This benefit is that call_rcu()
can be replaced by polling, which can be attractive in situations
where RCU-protected data is aged out of memory.
Early in the series, the size of this state value is three unsigned
longs. Later in the series, the fastpaths in synchronize_rcu() and
synchronize_rcu_expedited() are reworked to permit the full state to
be represented by only two unsigned longs. This reworking slows these
two functions down in SMP kernels running either on single-CPU
systems or on systems with all but one CPU offlined, but this should
not be a significant problem. And if it somehow becomes a problem in
some yet-as-unforeseen situations, three-value state values can be
provided for only those situations.
Finally, a pair of functions named same_state_synchronize_rcu() and
same_state_synchronize_rcu_full() allow grace-period state values to
be compared for equality. This permits users to maintain lists of
data structures having the same state value, removing the need for
per-data-structure grace-period state values, thus decreasing memory
footprint.
- Polled SRCU grace-period updates, including adding tests to
rcutorture and reducing the incidence of Tiny SRCU grace-period-state
counter wrap.
- Improve Tasks RCU diagnostics and quiescent-state detection.
* tag 'rcu.2022.09.30a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (55 commits)
rcutorture: Use the barrier operation specified by cur_ops
rcu-tasks: Make RCU Tasks Trace check for userspace execution
rcu-tasks: Ensure RCU Tasks Trace loops have quiescent states
rcu-tasks: Convert RCU_LOCKDEP_WARN() to WARN_ONCE()
srcu: Make Tiny SRCU use full-sized grace-period counters
srcu: Make Tiny SRCU poll_state_synchronize_srcu() more precise
srcu: Add GP and maximum requested GP to Tiny SRCU rcutorture output
rcutorture: Make "srcud" option also test polled grace-period API
rcutorture: Limit read-side polling-API testing
rcu: Add functions to compare grace-period state values
rcutorture: Expand rcu_torture_write_types() first "if" statement
rcutorture: Use 1-suffixed variable in rcu_torture_write_types() check
rcu: Make synchronize_rcu() fastpath update only boot-CPU counters
rcutorture: Adjust rcu_poll_need_2gp() for rcu_gp_oldstate field removal
rcu: Remove ->rgos_polled field from rcu_gp_oldstate structure
rcu: Make synchronize_rcu_expedited() fast path update .expedited_sequence
rcu: Remove expedited grace-period fast-path forward-progress helper
rcu: Make synchronize_rcu() fast path update ->gp_seq counters
rcu-tasks: Remove grace-period fast-path rcu-tasks helper
rcu: Set rcu_data structures' initial ->gpwrap value to true
...
Reported by Clang [-Wunused-but-set-variable]
'commit c193707dde ("tracing: Remove code which merges duplicates")'
This commit removed the code which merges duplicates in detect_dups(),
but forgot to delete the variable 'dups' which used to merge
duplicates in the loop.
Now only 'total_dups' is needed, remove 'dups' for clean code.
Link: https://lkml.kernel.org/r/20220930103236.253985-1-chenzhongjin@huawei.com
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Boris reported hung_task splats after commit 5aec788aeb ("sched: Fix
TASK_state comparisons"). Upon closer consideration of that change it
doesn't only exclude TASK_KILLABLE, but also TASK_IDLE.
Update the comment to reflect this fact and add an additional
TASK_NOLOAD test to exclude them.
Additionally, remove the TASK_FREEZABLE early exit from
check_hung_task(), a freezable task is not a frozen task.
Fixes: 5aec788aeb ("sched: Fix TASK_state comparisons")
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Borislav Petkov <bp@alien8.de>
On some small machines with little entropy, a quasi-unique hostname is
sometimes a relevant factor. I've seen, for example, 8 character
alpha-numeric serial numbers. In addition, the time at which the hostname
is set is usually a decent measurement of how long early boot took. So,
call add_device_randomness() on new hostnames, which feeds its arguments
to the RNG in addition to a fresh cycle counter.
Low cost hooks like this never hurt and can only ever help, and since
this costs basically nothing for an operation that is never a fast path,
this is an overall easy win.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The struct_ops prog is to allow using bpf to implement the functions in
a struct (eg. kernel module). The current usage is to implement the
tcp_congestion. The kernel does not call the tcp-cc's ops (ie.
the bpf prog) in a recursive way.
The struct_ops is sharing the tracing-trampoline's enter/exit
function which tracks prog->active to avoid recursion. It is
needed for tracing prog. However, it turns out the struct_ops
bpf prog will hit this prog->active and unnecessarily skipped
running the struct_ops prog. eg. The '.ssthresh' may run in_task()
and then interrupted by softirq that runs the same '.ssthresh'.
Skip running the '.ssthresh' will end up returning random value
to the caller.
The patch adds __bpf_prog_{enter,exit}_struct_ops for the
struct_ops trampoline. They do not track the prog->active
to detect recursion.
One exception is when the tcp_congestion's '.init' ops is doing
bpf_setsockopt(TCP_CONGESTION) and then recurs to the same
'.init' ops. This will be addressed in the following patches.
Fixes: ca06f55b90 ("bpf: Add per-program recursion prevention mechanism")
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220929070407.965581-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The ring buffer is broken up into sub buffers (currently of page size).
Each sub buffer has a pointer to its "tail" (the last event written to the
sub buffer). When a new event is requested, the tail is locally
incremented to cover the size of the new event. This is done in a way that
there is no need for locking.
If the tail goes past the end of the sub buffer, the process of moving to
the next sub buffer takes place. After setting the current sub buffer to
the next one, the previous one that had the tail go passed the end of the
sub buffer needs to be reset back to the original tail location (before
the new event was requested) and the rest of the sub buffer needs to be
"padded".
The race happens when a reader takes control of the sub buffer. As readers
do a "swap" of sub buffers from the ring buffer to get exclusive access to
the sub buffer, it replaces the "head" sub buffer with an empty sub buffer
that goes back into the writable portion of the ring buffer. This swap can
happen as soon as the writer moves to the next sub buffer and before it
updates the last sub buffer with padding.
Because the sub buffer can be released to the reader while the writer is
still updating the padding, it is possible for the reader to see the event
that goes past the end of the sub buffer. This can cause obvious issues.
To fix this, add a few memory barriers so that the reader definitely sees
the updates to the sub buffer, and also waits until the writer has put
back the "tail" of the sub buffer back to the last event that was written
on it.
To be paranoid, it will only spin for 1 second, otherwise it will
warn and shutdown the ring buffer code. 1 second should be enough as
the writer does have preemption disabled. If the writer doesn't move
within 1 second (with preemption disabled) something is horribly
wrong. No interrupt should last 1 second!
Link: https://lore.kernel.org/all/20220830120854.7545-1-jiazi.li@transsion.com/
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216369
Link: https://lkml.kernel.org/r/20220929104909.0650a36c@gandalf.local.home
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: c7b0930857 ("ring-buffer: prevent adding write in discarded area")
Reported-by: Jiazi.Li <jiazi.li@transsion.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
User processes may require many events and when they do the cache
performance of a byte index status check is less ideal than a bit index.
The previous event limit per-page was 4096, the new limit is 32,768.
This change adds a bitwise index to the user_reg struct. Programs check
that the bit at status_bit has a bit set within the status page(s).
Link: https://lkml.kernel.org/r/20220728233309.1896-6-beaub@linux.microsoft.com
Link: https://lore.kernel.org/all/2059213643.196683.1648499088753.JavaMail.zimbra@efficios.com/
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
User processes could open up enough event references to cause rollovers.
These could cause use after free scenarios, which we do not want.
Switching to refcount APIs prevent this, but will leak memory once
saturated.
Once saturated, user processes can still use the events. This prevents
a bad user process from stopping existing telemetry from being emitted.
Link: https://lkml.kernel.org/r/20220728233309.1896-5-beaub@linux.microsoft.com
Link: https://lore.kernel.org/all/2059213643.196683.1648499088753.JavaMail.zimbra@efficios.com/
Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When tracing is disabled, there's no reason that waiters should stay
waiting, wake them up, otherwise tasks get stuck when they should be
flushing the buffers.
Cc: stable@vger.kernel.org
Fixes: e30f53aad2 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
If a process is waiting on the ring buffer for data, there currently isn't
a clean way to force it to wake up. Add an ioctl call that will force any
tasks that are waiting on the trace_pipe_raw file to wake up.
Link: https://lkml.kernel.org/r/20220929095029.117f913f@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: e30f53aad2 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The comment about unregistering boot consoles is just not matching the
reality. Remove it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220924000454.3319186-5-john.ogness@linutronix.de
Commit a699449bb1 ("printk: refactor and rework printing logic")
removed the need for @nr_ext_console_drivers. Remove the unneeded
variable.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220924000454.3319186-4-john.ogness@linutronix.de
No user outside the printk code and no reason to export this.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220924000454.3319186-2-john.ogness@linutronix.de
IBS_DC_PHYSADDR provides the physical data address for the tagged load/
store operation. Populate perf sample physical address using it.
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220928095805.596-7-ravi.bangoria@amd.com
When the file that represents the ring buffer is closed, there may be
waiters waiting on more input from the ring buffer. Call
ring_buffer_wake_waiters() to wake up any waiters when the file is
closed.
Link: https://lkml.kernel.org/r/20220927231825.182416969@goodmis.org
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: e30f53aad2 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
On closing of a file that represents a ring buffer or flushing the file,
there may be waiters on the ring buffer that needs to be woken up and exit
the ring_buffer_wait() function.
Add ring_buffer_wake_waiters() to wake up the waiters on the ring buffer
and allow them to exit the wait loop.
Link: https://lkml.kernel.org/r/20220928133938.28dc2c27@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 15693458c4 ("tracing/ring-buffer: Move poll wake ups into ring buffer code")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Show information of iterators in the respective files under
/proc/<pid>/fdinfo/.
For example, for a task file iterator with 1723 as the value of tid
parameter, its fdinfo would look like the following lines.
pos: 0
flags: 02000000
mnt_id: 14
ino: 38
link_type: iter
link_id: 51
prog_tag: a590ac96db22b825
prog_id: 299
target_name: task_file
task_type: TID
tid: 1723
This patch add the last three fields. task_type is the type of the
task parameter. TID means the iterator visit only the thread
specified by tid. The value of tid in the above example is 1723. For
the case of PID task_type, it means the iterator visits only threads
of a process and will show the pid value of the process instead of a
tid.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20220926184957.208194-4-kuifeng@fb.com
Add new fields to bpf_link_info that users can query it through
bpf_obj_get_info_by_fd().
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20220926184957.208194-3-kuifeng@fb.com
Allow creating an iterator that loops through resources of one
thread/process.
People could only create iterators to loop through all resources of
files, vma, and tasks in the system, even though they were interested
in only the resources of a specific task or process. Passing the
additional parameters, people can now create an iterator to go
through all resources or only the resources of a task.
Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20220926184957.208194-2-kuifeng@fb.com
Kbuild builds init/built-in.a twice; first during the ordinary
directory descending, second from scripts/link-vmlinux.sh.
We do this because UTS_VERSION contains the build version and the
timestamp. We cannot update it during the normal directory traversal
since we do not yet know if we need to update vmlinux. UTS_VERSION is
temporarily calculated, but omitted from the update check. Otherwise,
vmlinux would be rebuilt every time.
When Kbuild results in running link-vmlinux.sh, it increments the
version number in the .version file and takes the timestamp at that
time to really fix UTS_VERSION.
However, updating the same file twice is a footgun. To avoid nasty
timestamp issues, all build artifacts that depend on init/built-in.a
are atomically generated in link-vmlinux.sh, where some of them do not
need rebuilding.
To fix this issue, this commit changes as follows:
[1] Split UTS_VERSION out to include/generated/utsversion.h from
include/generated/compile.h
include/generated/utsversion.h is generated just before the
vmlinux link. It is generated under include/generated/ because
some decompressors (s390, x86) use UTS_VERSION.
[2] Split init_uts_ns and linux_banner out to init/version-timestamp.c
from init/version.c
init_uts_ns and linux_banner contain UTS_VERSION. During the ordinary
directory descending, they are compiled with __weak and used to
determine if vmlinux needs relinking. Just before the vmlinux link,
they are compiled without __weak to embed the real version and
timestamp.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Task state is fundamentally a bitmask; direct comparisons are probably
not working as intended. Specifically the normal wait-state have
a number of possible modifiers:
TASK_UNINTERRUPTIBLE: TASK_WAKEKILL, TASK_NOLOAD, TASK_FREEZABLE
TASK_INTERRUPTIBLE: TASK_FREEZABLE
Specifically, the addition of TASK_FREEZABLE wrecked
__wait_is_interruptible(). This however led to an audit of direct
comparisons yielding the rest of the changes.
Fixes: f5d39b0208 ("freezer,sched: Rewrite core freezer logic")
Reported-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Debugged-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Having most of the new files in place, we now enable Rust support
in the build system, including `Kconfig` entries related to Rust,
the Rust configuration printer and a few other bits.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Finn Behrens <me@kloenk.de>
Signed-off-by: Finn Behrens <me@kloenk.de>
Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de>
Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Co-developed-by: Douglas Su <d0u9.su@outlook.com>
Signed-off-by: Douglas Su <d0u9.su@outlook.com>
Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl>
Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl>
Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org>
Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org>
Co-developed-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Rust symbols can become quite long due to namespacing introduced
by modules, types, traits, generics, etc. For instance,
the following code:
pub mod my_module {
pub struct MyType;
pub struct MyGenericType<T>(T);
pub trait MyTrait {
fn my_method() -> u32;
}
impl MyTrait for MyGenericType<MyType> {
fn my_method() -> u32 {
42
}
}
}
generates a symbol of length 96 when using the upcoming v0 mangling scheme:
_RNvXNtCshGpAVYOtgW1_7example9my_moduleINtB2_13MyGenericTypeNtB2_6MyTypeENtB2_7MyTrait9my_method
At the moment, Rust symbols may reach up to 300 in length.
Setting 512 as the maximum seems like a reasonable choice to
keep some headroom.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Rust symbols can become quite long due to namespacing introduced
by modules, types, traits, generics, etc.
Increasing to 255 is not enough in some cases, therefore
introduce longer lengths to the symbol table.
In order to avoid increasing all lengths to 2 bytes (since most
of them are small, including many Rust ones), use ULEB128 to
keep smaller symbols in 1 byte, with the rest in 2 bytes.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Co-developed-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
The wake up waiters only checks the "wakeup_full" variable and not the
"full_waiters_pending". The full_waiters_pending is set when a waiter is
added to the wait queue. The wakeup_full is only set when an event is
triggered, and it clears the full_waiters_pending to avoid multiple calls
to irq_work_queue().
The irq_work callback really needs to check both wakeup_full as well as
full_waiters_pending such that this code can be used to wake up waiters
when a file is closed that represents the ring buffer and the waiters need
to be woken up.
Link: https://lkml.kernel.org/r/20220927231824.209460321@goodmis.org
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 15693458c4 ("tracing/ring-buffer: Move poll wake ups into ring buffer code")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The logic to know when the shortest waiters on the ring buffer should be
woken up or not has uses a less than instead of a greater than compare,
which causes the shortest_full to actually be the longest.
Link: https://lkml.kernel.org/r/20220927231823.718039222@goodmis.org
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 2c2b0a78b3 ("ring-buffer: Add percentage of ring buffer full to wake up reader")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Recent commit [1] changed branch stack data indication from
br_stack pointer to sample_flags in perf_sample_data struct.
We need to check sample_flags for PERF_SAMPLE_BRANCH_STACK
bit for valid branch stack data.
[1] a9a931e266 ("perf: Use sample_flags for branch stack")
Fixes: a9a931e266 ("perf: Use sample_flags for branch stack")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20220927203259.590950-1-jolsa@kernel.org
Local testing revealed that we can trigger a use-after-free during
rhashtable lookup as follows:
| BUG: KASAN: use-after-free in memcmp lib/string.c:757
| Read of size 8 at addr ffff888107544dc0 by task perf-rhltable-n/1293
|
| CPU: 0 PID: 1293 Comm: perf-rhltable-n Not tainted 6.0.0-rc3-00014-g85260862789c #46
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014
| Call Trace:
| <TASK>
| memcmp lib/string.c:757
| rhashtable_compare include/linux/rhashtable.h:577 [inline]
| __rhashtable_lookup include/linux/rhashtable.h:602 [inline]
| rhltable_lookup include/linux/rhashtable.h:688 [inline]
| task_bp_pinned kernel/events/hw_breakpoint.c:324
| toggle_bp_slot kernel/events/hw_breakpoint.c:462
| __release_bp_slot kernel/events/hw_breakpoint.c:631 [inline]
| release_bp_slot kernel/events/hw_breakpoint.c:639
| register_perf_hw_breakpoint kernel/events/hw_breakpoint.c:742
| hw_breakpoint_event_init kernel/events/hw_breakpoint.c:976
| perf_try_init_event kernel/events/core.c:11261
| perf_init_event kernel/events/core.c:11325 [inline]
| perf_event_alloc kernel/events/core.c:11619
| __do_sys_perf_event_open kernel/events/core.c:12157
| do_syscall_x64 arch/x86/entry/common.c:50 [inline]
| do_syscall_64 arch/x86/entry/common.c:80
| entry_SYSCALL_64_after_hwframe
| </TASK>
|
| Allocated by task 1292:
| perf_event_alloc kernel/events/core.c:11505
| __do_sys_perf_event_open kernel/events/core.c:12157
| do_syscall_x64 arch/x86/entry/common.c:50 [inline]
| do_syscall_64 arch/x86/entry/common.c:80
| entry_SYSCALL_64_after_hwframe
|
| Freed by task 1292:
| perf_event_alloc kernel/events/core.c:11716
| __do_sys_perf_event_open kernel/events/core.c:12157
| do_syscall_x64 arch/x86/entry/common.c:50 [inline]
| do_syscall_64 arch/x86/entry/common.c:80
| entry_SYSCALL_64_after_hwframe
|
| The buggy address belongs to the object at ffff888107544c00
| which belongs to the cache perf_event of size 1352
| The buggy address is located 448 bytes inside of
| 1352-byte region [ffff888107544c00, ffff888107545148)
This happens because the first perf_event_open() managed to reserve a HW
breakpoint slot, however, later fails for other reasons and returns. The
second perf_event_open() runs concurrently, and during rhltable_lookup()
looks up an entry which is being freed: since rhltable_lookup() may run
concurrently (under the RCU read lock) with rhltable_remove(), we may
end up with a stale entry, for which memory may also have already been
freed when being accessed.
To fix, only free the failed perf_event after an RCU grace period. This
allows subsystems that store references to an event to always access it
concurrently under the RCU read lock, even if initialization will fail.
Given failure is unlikely and a slow-path, turning the immediate free
into a call_rcu()-wrapped free does not affect performance elsewhere.
Fixes: 0370dc314d ("perf/hw_breakpoint: Optimize list of per-task breakpoints")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220927172025.1636995-1-elver@google.com
Use the new sample_flags to indicate whether the raw data field is
filled by the PMU driver. Although it could check with the NULL,
follow the same rule with other fields.
Remove the raw field from the perf_sample_data_init() to minimize
the number of cache lines touched.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220921220032.2858517-2-namhyung@kernel.org
Use the new sample_flags to indicate whether the addr field is filled by
the PMU driver. As most PMU drivers pass 0, it can set the flag only if
it has a non-zero value. And use 0 in perf_sample_output() if it's not
filled already.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220921220032.2858517-1-namhyung@kernel.org
If a page is partially read, and then the splice system call is run
against the ring buffer, it will always fail to read, no matter how much
is in the ring buffer. That's because the code path for a partial read of
the page does will fail if the "full" flag is set.
The splice system call wants full pages, so if the read of the ring buffer
is not yet full, it should return zero, and the splice will block. But if
a previous read was done, where the beginning has been consumed, it should
still be given to the splice caller if the rest of the page has been
written to.
This caused the splice command to never consume data in this scenario, and
let the ring buffer just fill up and lose events.
Link: https://lkml.kernel.org/r/20220927144317.46be6b80@gandalf.local.home
Cc: stable@vger.kernel.org
Fixes: 8789a9e7df ("ring-buffer: read page interface")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When executing following commands like what document said, but the log
"#### all functions enabled ####" was not shown as expect:
1. Set a 'mod' filter:
$ echo 'write*:mod:ext3' > /sys/kernel/tracing/set_ftrace_filter
2. Invert above filter:
$ echo '!write*:mod:ext3' >> /sys/kernel/tracing/set_ftrace_filter
3. Read the file:
$ cat /sys/kernel/tracing/set_ftrace_filter
By some debugging, I found that flag FTRACE_HASH_FL_MOD was not unset
after inversion like above step 2 and then result of ftrace_hash_empty()
is incorrect.
Link: https://lkml.kernel.org/r/20220926152008.2239274-1-zhengyejian1@huawei.com
Cc: <mingo@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 8c08f0d5c6 ("ftrace: Have cached module filters be an active filter")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The event dir will alloc failed when event name no set, using the
command:
"echo "e:esys/ syscalls/sys_enter_openat file=\$filename:string"
>> dynamic_events"
It seems that dir name="syscalls/sys_enter_openat" is not allowed
in debugfs. So just use the "sys_enter_openat" as the event name.
Link: https://lkml.kernel.org/r/1664028814-45923-1-git-send-email-chentao.kernel@linux.alibaba.com
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Linyu Yuan <quic_linyyuan@quicinc.com>
Cc: Tao Chen <chentao.kernel@linux.alibaba.com
Cc: stable@vger.kernel.org
Fixes: 95c104c378 ("tracing: Auto generate event name when creating a group of events")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Tao Chen <chentao.kernel@linux.alibaba.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
It was found that some tracing functions in kernel/trace/trace.c acquire
an arch_spinlock_t with preemption and irqs enabled. An example is the
tracing_saved_cmdlines_size_read() function which intermittently causes
a "BUG: using smp_processor_id() in preemptible" warning when the LTP
read_all_proc test is run.
That can be problematic in case preemption happens after acquiring the
lock. Add the necessary preemption or interrupt disabling code in the
appropriate places before acquiring an arch_spinlock_t.
The convention here is to disable preemption for trace_cmdline_lock and
interupt for max_lock.
Link: https://lkml.kernel.org/r/20220922145622.1744826-1-longman@redhat.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: stable@vger.kernel.org
Fixes: a35873a099 ("tracing: Add conditional snapshot")
Fixes: 939c7a4f04 ("tracing: Introduce saved_cmdlines_size file")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Mark the trampoline as RO+X after arch_prepare_bpf_trampoline, so that
the trampoine follows W^X rule strictly. This will turn off warnings like
CPA refuse W^X violation: 8000000000000163 -> 0000000000000163 range: ...
Also remove bpf_jit_alloc_exec_page(), since it is not used any more.
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220926184739.3512547-3-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allocate bpf_dispatcher with bpf_prog_pack_alloc so that bpf_dispatcher
can share pages with bpf programs.
arch_prepare_bpf_dispatcher() is updated to provide a RW buffer as working
area for arch code to write to.
This also fixes CPA W^X warnning like:
CPA refuse W^X violation: 8000000000000163 -> 0000000000000163 range: ...
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220926184739.3512547-2-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Changing return value of kprobe's version of bpf_get_func_ip
to return zero if the attach address is not on the function's
entry point.
For kprobes attached in the middle of the function we can't easily
get to the function address especially now with the CONFIG_X86_KERNEL_IBT
support.
If user cares about current IP for kprobes attached within the
function body, they can get it with PT_REGS_IP(ctx).
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martynas Pumputis <m@lambda.lt>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220926153340.1621984-6-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Martynas reported bpf_get_func_ip returning +4 address when
CONFIG_X86_KERNEL_IBT option is enabled.
When CONFIG_X86_KERNEL_IBT is enabled we'll have endbr instruction
at the function entry, which screws return value of bpf_get_func_ip()
helper that should return the function address.
There's short term workaround for kprobe_multi bpf program made by
Alexei [1], but we need this fixup also for bpf_get_attach_cookie,
that returns cookie based on the entry_ip value.
Moving the fixup in the fprobe handler, so both bpf_get_func_ip
and bpf_get_attach_cookie get expected function address when
CONFIG_X86_KERNEL_IBT option is enabled.
Also renaming kprobe_multi_link_handler entry_ip argument to fentry_ip
so it's clearer this is an ftrace __fentry__ ip.
[1] commit 7f0059b58f ("selftests/bpf: Fix kprobe_multi test.")
Cc: Peter Zijlstra <peterz@infradead.org>
Reported-by: Martynas Pumputis <m@lambda.lt>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220926153340.1621984-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Keeping the resolved 'addr' in kallsyms_callback, instead of taking
ftrace_location value, because we depend on symbol address in the
cookie related code.
With CONFIG_X86_KERNEL_IBT option the ftrace_location value differs
from symbol address, which screwes the symbol address cookies matching.
There are 2 users of this function:
- bpf_kprobe_multi_link_attach
for which this fix is for
- get_ftrace_locations
which is used by register_fprobe_syms
this function needs to get symbols resolved to addresses,
but does not need 'ftrace location addresses' at this point
there's another ftrace location translation in the path done
by ftrace_set_filter_ips call:
register_fprobe_syms
addrs = get_ftrace_locations
register_fprobe_ips(addrs)
...
ftrace_set_filter_ips
...
__ftrace_match_addr
ip = ftrace_location(ip);
...
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220926153340.1621984-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Adding KPROBE_FLAG_ON_FUNC_ENTRY kprobe flag to indicate that
attach address is on function entry. This is used in following
changes in get_func_ip helper to return correct function address.
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220926153340.1621984-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Replace any vm_next use with vma_find().
Update free_pgtables(), unmap_vmas(), and zap_page_range() to use the
maple tree.
Use the new free_pgtables() and unmap_vmas() in do_mas_align_munmap(). At
the same time, alter the loop to be more compact.
Now that free_pgtables() and unmap_vmas() take a maple tree as an
argument, rearrange do_mas_align_munmap() to use the new tree to hold the
vmas to remove.
Remove __vma_link_list() and __vma_unlink_list() as they are exclusively
used to update the linked list.
Drop linked list update from __insert_vm_struct().
Rework validation of tree as it was depending on the linked list.
[yang.lee@linux.alibaba.com: fix one kernel-doc comment]
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=1949
Link: https://lkml.kernel.org/r/20220824021918.94116-1-yang.lee@linux.alibaba.comLink: https://lkml.kernel.org/r/20220906194824.2110408-69-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use vma_next() and remove reference to the start of the linked list
Link: https://lkml.kernel.org/r/20220906194824.2110408-51-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The VMA iterator is faster than the linked list and removing the linked
list will shrink the vm_area_struct.
Link: https://lkml.kernel.org/r/20220906194824.2110408-50-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The linked list is slower than walking the VMAs using the maple tree. We
can't use the VMA iterator here because it doesn't support moving to an
earlier position.
Link: https://lkml.kernel.org/r/20220906194824.2110408-49-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The VMA iterator is faster than the linked list and removing the linked
list will shrink the vm_area_struct.
Link: https://lkml.kernel.org/r/20220906194824.2110408-48-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
By using the maple tree and the maple tree state, the vmacache is no
longer beneficial and is complicating the VMA code. Remove the vmacache
to reduce the work in keeping it up to date and code complexity.
Link: https://lkml.kernel.org/r/20220906194824.2110408-26-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Remove the RB tree and start using the maple tree for vm_area_struct
tracking.
Drop validate_mm() calls in expand_upwards() and expand_downwards() as the
lock is not held.
Link: https://lkml.kernel.org/r/20220906194824.2110408-18-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The maple tree was already tracking VMAs in this function by an earlier
commit, but the rbtree iterator was being used to iterate the list.
Change the iterator to use a maple tree native iterator and switch to the
maple tree advanced API to avoid multiple walks of the tree during insert
operations. Unexport the now-unused vma_store() function.
For performance reasons we bulk allocate the maple tree nodes. The node
calculations are done internally to the tree and use the VMA count and
assume the worst-case node requirements. The VM_DONT_COPY flag does not
allow for the most efficient copy method of the tree and so a bulk loading
algorithm is used.
Link: https://lkml.kernel.org/r/20220906194824.2110408-15-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Start tracking the VMAs with the new maple tree structure in parallel with
the rb_tree. Add debug and trace events for maple tree operations and
duplicate the rb_tree that is created on forks into the maple tree.
The maple tree is added to the mm_struct including the mm_init struct,
added support in required mm/mmap functions, added tracking in kernel/fork
for process forking, and used to find the unmapped_area and checked
against what the rbtree finds.
This also moves the mmap_lock() in exit_mmap() since the oom reaper call
does walk the VMAs. Otherwise lockdep will be unhappy if oom happens.
When splitting a vma fails due to allocations of the maple tree nodes,
the error path in __split_vma() calls new->vm_ops->close(new). The page
accounting for hugetlb is actually in the close() operation, so it
accounts for the removal of 1/2 of the VMA which was not adjusted. This
results in a negative exit value. To avoid the negative charge, set
vm_start = vm_end and vm_pgoff = 0.
There is also a potential accounting issue in special mappings from
insert_vm_struct() failing to allocate, so reverse the charge there in
the failure scenario.
Link: https://lkml.kernel.org/r/20220906194824.2110408-9-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
With memory tier support we can have memory only NUMA nodes in the top
tier from which we want to avoid promotion tracking NUMA faults. Update
node_is_toptier to work with memory tiers. All NUMA nodes are by default
top tier nodes. With lower(slower) memory tiers added we consider all
memory tiers above a memory tier having CPU NUMA nodes as a top memory
tier
[sj@kernel.org: include missed header file, memory-tiers.h]
Link: https://lkml.kernel.org/r/20220820190720.248704-1-sj@kernel.org
[akpm@linux-foundation.org: mm/memory.c needs linux/memory-tiers.h]
[aneesh.kumar@linux.ibm.com: make toptier_distance inclusive upper bound of toptiers]
Link: https://lkml.kernel.org/r/20220830081457.118960-1-aneesh.kumar@linux.ibm.com
Link: https://lkml.kernel.org/r/20220818131042.113280-10-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Wei Xu <weixugc@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Bharata B Rao <bharata@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hesham Almatary <hesham.almatary@huawei.com>
Cc: Jagdish Gediya <jvgediya.oss@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add /sys/kernel/mm/lru_gen/enabled as a kill switch. Components that
can be disabled include:
0x0001: the multi-gen LRU core
0x0002: walking page table, when arch_has_hw_pte_young() returns
true
0x0004: clearing the accessed bit in non-leaf PMD entries, when
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG=y
[yYnN]: apply to all the components above
E.g.,
echo y >/sys/kernel/mm/lru_gen/enabled
cat /sys/kernel/mm/lru_gen/enabled
0x0007
echo 5 >/sys/kernel/mm/lru_gen/enabled
cat /sys/kernel/mm/lru_gen/enabled
0x0005
NB: the page table walks happen on the scale of seconds under heavy memory
pressure, in which case the mmap_lock contention is a lesser concern,
compared with the LRU lock contention and the I/O congestion. So far the
only well-known case of the mmap_lock contention happens on Android, due
to Scudo [1] which allocates several thousand VMAs for merely a few
hundred MBs. The SPF and the Maple Tree also have provided their own
assessments [2][3]. However, if walking page tables does worsen the
mmap_lock contention, the kill switch can be used to disable it. In this
case the multi-gen LRU will suffer a minor performance degradation, as
shown previously.
Clearing the accessed bit in non-leaf PMD entries can also be disabled,
since this behavior was not tested on x86 varieties other than Intel and
AMD.
[1] https://source.android.com/devices/tech/debug/scudo
[2] https://lore.kernel.org/r/20220128131006.67712-1-michel@lespinasse.org/
[3] https://lore.kernel.org/r/20220426150616.3937571-1-Liam.Howlett@oracle.com/
Link: https://lkml.kernel.org/r/20220918080010.2920238-11-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Acked-by: Steven Barrett <steven@liquorix.net>
Acked-by: Suleiman Souhlal <suleiman@google.com>
Tested-by: Daniel Byrne <djbyrne@mtu.edu>
Tested-by: Donald Carr <d@chaos-reins.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
Tested-by: Shuang Zhai <szhai2@cs.rochester.edu>
Tested-by: Sofia Trinh <sofia.trinh@edi.works>
Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
To further exploit spatial locality, the aging prefers to walk page tables
to search for young PTEs and promote hot pages. A kill switch will be
added in the next patch to disable this behavior. When disabled, the
aging relies on the rmap only.
NB: this behavior has nothing similar with the page table scanning in the
2.4 kernel [1], which searches page tables for old PTEs, adds cold pages
to swapcache and unmaps them.
To avoid confusion, the term "iteration" specifically means the traversal
of an entire mm_struct list; the term "walk" will be applied to page
tables and the rmap, as usual.
An mm_struct list is maintained for each memcg, and an mm_struct follows
its owner task to the new memcg when this task is migrated. Given an
lruvec, the aging iterates lruvec_memcg()->mm_list and calls
walk_page_range() with each mm_struct on this list to promote hot pages
before it increments max_seq.
When multiple page table walkers iterate the same list, each of them gets
a unique mm_struct; therefore they can run concurrently. Page table
walkers ignore any misplaced pages, e.g., if an mm_struct was migrated,
pages it left in the previous memcg will not be promoted when its current
memcg is under reclaim. Similarly, page table walkers will not promote
pages from nodes other than the one under reclaim.
This patch uses the following optimizations when walking page tables:
1. It tracks the usage of mm_struct's between context switches so that
page table walkers can skip processes that have been sleeping since
the last iteration.
2. It uses generational Bloom filters to record populated branches so
that page table walkers can reduce their search space based on the
query results, e.g., to skip page tables containing mostly holes or
misplaced pages.
3. It takes advantage of the accessed bit in non-leaf PMD entries when
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG=y.
4. It does not zigzag between a PGD table and the same PMD table
spanning multiple VMAs. IOW, it finishes all the VMAs within the
range of the same PMD table before it returns to a PGD table. This
improves the cache performance for workloads that have large
numbers of tiny VMAs [2], especially when CONFIG_PGTABLE_LEVELS=5.
Server benchmark results:
Single workload:
fio (buffered I/O): no change
Single workload:
memcached (anon): +[8, 10]%
Ops/sec KB/sec
patch1-7: 1147696.57 44640.29
patch1-8: 1245274.91 48435.66
Configurations:
no change
Client benchmark results:
kswapd profiles:
patch1-7
48.16% lzo1x_1_do_compress (real work)
8.20% page_vma_mapped_walk (overhead)
7.06% _raw_spin_unlock_irq
2.92% ptep_clear_flush
2.53% __zram_bvec_write
2.11% do_raw_spin_lock
2.02% memmove
1.93% lru_gen_look_around
1.56% free_unref_page_list
1.40% memset
patch1-8
49.44% lzo1x_1_do_compress (real work)
6.19% page_vma_mapped_walk (overhead)
5.97% _raw_spin_unlock_irq
3.13% get_pfn_folio
2.85% ptep_clear_flush
2.42% __zram_bvec_write
2.08% do_raw_spin_lock
1.92% memmove
1.44% alloc_zspage
1.36% memset
Configurations:
no change
Thanks to the following developers for their efforts [3].
kernel test robot <lkp@intel.com>
[1] https://lwn.net/Articles/23732/
[2] https://llvm.org/docs/ScudoHardenedAllocator.html
[3] https://lore.kernel.org/r/202204160827.ekEARWQo-lkp@intel.com/
Link: https://lkml.kernel.org/r/20220918080010.2920238-9-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Acked-by: Steven Barrett <steven@liquorix.net>
Acked-by: Suleiman Souhlal <suleiman@google.com>
Tested-by: Daniel Byrne <djbyrne@mtu.edu>
Tested-by: Donald Carr <d@chaos-reins.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
Tested-by: Shuang Zhai <szhai2@cs.rochester.edu>
Tested-by: Sofia Trinh <sofia.trinh@edi.works>
Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
To avoid confusion, the terms "promotion" and "demotion" will be applied
to the multi-gen LRU, as a new convention; the terms "activation" and
"deactivation" will be applied to the active/inactive LRU, as usual.
The aging produces young generations. Given an lruvec, it increments
max_seq when max_seq-min_seq+1 approaches MIN_NR_GENS. The aging promotes
hot pages to the youngest generation when it finds them accessed through
page tables; the demotion of cold pages happens consequently when it
increments max_seq. Promotion in the aging path does not involve any LRU
list operations, only the updates of the gen counter and
lrugen->nr_pages[]; demotion, unless as the result of the increment of
max_seq, requires LRU list operations, e.g., lru_deactivate_fn(). The
aging has the complexity O(nr_hot_pages), since it is only interested in
hot pages.
The eviction consumes old generations. Given an lruvec, it increments
min_seq when lrugen->lists[] indexed by min_seq%MAX_NR_GENS becomes empty.
A feedback loop modeled after the PID controller monitors refaults over
anon and file types and decides which type to evict when both types are
available from the same generation.
The protection of pages accessed multiple times through file descriptors
takes place in the eviction path. Each generation is divided into
multiple tiers. A page accessed N times through file descriptors is in
tier order_base_2(N). Tiers do not have dedicated lrugen->lists[], only
bits in folio->flags. The aforementioned feedback loop also monitors
refaults over all tiers and decides when to protect pages in which tiers
(N>1), using the first tier (N=0,1) as a baseline. The first tier
contains single-use unmapped clean pages, which are most likely the best
choices. In contrast to promotion in the aging path, the protection of a
page in the eviction path is achieved by moving this page to the next
generation, i.e., min_seq+1, if the feedback loop decides so. This
approach has the following advantages:
1. It removes the cost of activation in the buffered access path by
inferring whether pages accessed multiple times through file
descriptors are statistically hot and thus worth protecting in the
eviction path.
2. It takes pages accessed through page tables into account and avoids
overprotecting pages accessed multiple times through file
descriptors. (Pages accessed through page tables are in the first
tier, since N=0.)
3. More tiers provide better protection for pages accessed more than
twice through file descriptors, when under heavy buffered I/O
workloads.
Server benchmark results:
Single workload:
fio (buffered I/O): +[30, 32]%
IOPS BW
5.19-rc1: 2673k 10.2GiB/s
patch1-6: 3491k 13.3GiB/s
Single workload:
memcached (anon): -[4, 6]%
Ops/sec KB/sec
5.19-rc1: 1161501.04 45177.25
patch1-6: 1106168.46 43025.04
Configurations:
CPU: two Xeon 6154
Mem: total 256G
Node 1 was only used as a ram disk to reduce the variance in the
results.
patch drivers/block/brd.c <<EOF
99,100c99,100
< gfp_flags = GFP_NOIO | __GFP_ZERO | __GFP_HIGHMEM;
< page = alloc_page(gfp_flags);
---
> gfp_flags = GFP_NOIO | __GFP_ZERO | __GFP_HIGHMEM | __GFP_THISNODE;
> page = alloc_pages_node(1, gfp_flags, 0);
EOF
cat >>/etc/systemd/system.conf <<EOF
CPUAffinity=numa
NUMAPolicy=bind
NUMAMask=0
EOF
cat >>/etc/memcached.conf <<EOF
-m 184320
-s /var/run/memcached/memcached.sock
-a 0766
-t 36
-B binary
EOF
cat fio.sh
modprobe brd rd_nr=1 rd_size=113246208
swapoff -a
mkfs.ext4 /dev/ram0
mount -t ext4 /dev/ram0 /mnt
mkdir /sys/fs/cgroup/user.slice/test
echo 38654705664 >/sys/fs/cgroup/user.slice/test/memory.max
echo $$ >/sys/fs/cgroup/user.slice/test/cgroup.procs
fio -name=mglru --numjobs=72 --directory=/mnt --size=1408m \
--buffered=1 --ioengine=io_uring --iodepth=128 \
--iodepth_batch_submit=32 --iodepth_batch_complete=32 \
--rw=randread --random_distribution=random --norandommap \
--time_based --ramp_time=10m --runtime=5m --group_reporting
cat memcached.sh
modprobe brd rd_nr=1 rd_size=113246208
swapoff -a
mkswap /dev/ram0
swapon /dev/ram0
memtier_benchmark -S /var/run/memcached/memcached.sock \
-P memcache_binary -n allkeys --key-minimum=1 \
--key-maximum=65000000 --key-pattern=P:P -c 1 -t 36 \
--ratio 1:0 --pipeline 8 -d 2000
memtier_benchmark -S /var/run/memcached/memcached.sock \
-P memcache_binary -n allkeys --key-minimum=1 \
--key-maximum=65000000 --key-pattern=R:R -c 1 -t 36 \
--ratio 0:1 --pipeline 8 --randomize --distinct-client-seed
Client benchmark results:
kswapd profiles:
5.19-rc1
40.33% page_vma_mapped_walk (overhead)
21.80% lzo1x_1_do_compress (real work)
7.53% do_raw_spin_lock
3.95% _raw_spin_unlock_irq
2.52% vma_interval_tree_iter_next
2.37% folio_referenced_one
2.28% vma_interval_tree_subtree_search
1.97% anon_vma_interval_tree_iter_first
1.60% ptep_clear_flush
1.06% __zram_bvec_write
patch1-6
39.03% lzo1x_1_do_compress (real work)
18.47% page_vma_mapped_walk (overhead)
6.74% _raw_spin_unlock_irq
3.97% do_raw_spin_lock
2.49% ptep_clear_flush
2.48% anon_vma_interval_tree_iter_first
1.92% folio_referenced_one
1.88% __zram_bvec_write
1.48% memmove
1.31% vma_interval_tree_iter_next
Configurations:
CPU: single Snapdragon 7c
Mem: total 4G
ChromeOS MemoryPressure [1]
[1] https://chromium.googlesource.com/chromiumos/platform/tast-tests/
Link: https://lkml.kernel.org/r/20220918080010.2920238-7-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Acked-by: Steven Barrett <steven@liquorix.net>
Acked-by: Suleiman Souhlal <suleiman@google.com>
Tested-by: Daniel Byrne <djbyrne@mtu.edu>
Tested-by: Donald Carr <d@chaos-reins.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
Tested-by: Shuang Zhai <szhai2@cs.rochester.edu>
Tested-by: Sofia Trinh <sofia.trinh@edi.works>
Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Evictable pages are divided into multiple generations for each lruvec.
The youngest generation number is stored in lrugen->max_seq for both
anon and file types as they are aged on an equal footing. The oldest
generation numbers are stored in lrugen->min_seq[] separately for anon
and file types as clean file pages can be evicted regardless of swap
constraints. These three variables are monotonically increasing.
Generation numbers are truncated into order_base_2(MAX_NR_GENS+1) bits
in order to fit into the gen counter in folio->flags. Each truncated
generation number is an index to lrugen->lists[]. The sliding window
technique is used to track at least MIN_NR_GENS and at most
MAX_NR_GENS generations. The gen counter stores a value within [1,
MAX_NR_GENS] while a page is on one of lrugen->lists[]. Otherwise it
stores 0.
There are two conceptually independent procedures: "the aging", which
produces young generations, and "the eviction", which consumes old
generations. They form a closed-loop system, i.e., "the page reclaim".
Both procedures can be invoked from userspace for the purposes of working
set estimation and proactive reclaim. These techniques are commonly used
to optimize job scheduling (bin packing) in data centers [1][2].
To avoid confusion, the terms "hot" and "cold" will be applied to the
multi-gen LRU, as a new convention; the terms "active" and "inactive" will
be applied to the active/inactive LRU, as usual.
The protection of hot pages and the selection of cold pages are based
on page access channels and patterns. There are two access channels:
one through page tables and the other through file descriptors. The
protection of the former channel is by design stronger because:
1. The uncertainty in determining the access patterns of the former
channel is higher due to the approximation of the accessed bit.
2. The cost of evicting the former channel is higher due to the TLB
flushes required and the likelihood of encountering the dirty bit.
3. The penalty of underprotecting the former channel is higher because
applications usually do not prepare themselves for major page
faults like they do for blocked I/O. E.g., GUI applications
commonly use dedicated I/O threads to avoid blocking rendering
threads.
There are also two access patterns: one with temporal locality and the
other without. For the reasons listed above, the former channel is
assumed to follow the former pattern unless VM_SEQ_READ or VM_RAND_READ is
present; the latter channel is assumed to follow the latter pattern unless
outlying refaults have been observed [3][4].
The next patch will address the "outlying refaults". Three macros, i.e.,
LRU_REFS_WIDTH, LRU_REFS_PGOFF and LRU_REFS_MASK, used later are added in
this patch to make the entire patchset less diffy.
A page is added to the youngest generation on faulting. The aging needs
to check the accessed bit at least twice before handing this page over to
the eviction. The first check takes care of the accessed bit set on the
initial fault; the second check makes sure this page has not been used
since then. This protocol, AKA second chance, requires a minimum of two
generations, hence MIN_NR_GENS.
[1] https://dl.acm.org/doi/10.1145/3297858.3304053
[2] https://dl.acm.org/doi/10.1145/3503222.3507731
[3] https://lwn.net/Articles/495543/
[4] https://lwn.net/Articles/815342/
Link: https://lkml.kernel.org/r/20220918080010.2920238-6-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Acked-by: Steven Barrett <steven@liquorix.net>
Acked-by: Suleiman Souhlal <suleiman@google.com>
Tested-by: Daniel Byrne <djbyrne@mtu.edu>
Tested-by: Donald Carr <d@chaos-reins.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
Tested-by: Shuang Zhai <szhai2@cs.rochester.edu>
Tested-by: Sofia Trinh <sofia.trinh@edi.works>
Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Once upon a time, we only support accounting thrashing of page cache.
Then Joonsoo introduced workingset detection for anonymous pages and we
gained the ability to account thrashing of them[1].
For page cache thrashing accounting, there is no suitable place to do it
in fs level likes swap_readpage(). So we have to do it in
folio_wait_bit_common().
Then for anonymous pages thrashing accounting, we have to do it in both
swap_readpage() and folio_wait_bit_common(). This likes PSI, so we should
let thrashing accounting supports re-entrance detection.
This patch is to prepare complete thrashing accounting, and is based on
patch "filemap: make the accounting of thrashing more consistent".
[1] commit aae466b005 ("mm/swap: implement workingset detection for anonymous LRU")
Link: https://lkml.kernel.org/r/20220815071134.74551-1-yang.yang29@zte.com.cn
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: CGEL ZTE <cgel.zte@gmail.com>
Reviewed-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Reviewed-by: wangyong <wang.yong12@zte.com.cn>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is a recursive lock on the cpu_hotplug_lock.
In kernel/trace/trace_osnoise.c:<start/stop>_per_cpu_kthreads:
- start_per_cpu_kthreads calls cpus_read_lock() and if
start_kthreads returns a error it will call stop_per_cpu_kthreads.
- stop_per_cpu_kthreads then calls cpus_read_lock() again causing
deadlock.
Fix this by calling cpus_read_unlock() before calling
stop_per_cpu_kthreads. This behavior can also be seen in commit
f46b16520a ("trace/hwlat: Implement the per-cpu mode").
This error was noticed during the LTP ftrace-stress-test:
WARNING: possible recursive locking detected
--------------------------------------------
sh/275006 is trying to acquire lock:
ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: stop_per_cpu_kthreads
but task is already holding lock:
ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: start_per_cpu_kthreads
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(cpu_hotplug_lock);
lock(cpu_hotplug_lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by sh/275006:
#0: ffff8881023f0470 (sb_writers#24){.+.+}-{0:0}, at: ksys_write
#1: ffffffffb084f430 (trace_types_lock){+.+.}-{3:3}, at: rb_simple_write
#2: ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: start_per_cpu_kthreads
Link: https://lkml.kernel.org/r/20220919144932.3064014-1-npache@redhat.com
Fixes: c8895e271f ("trace/osnoise: Support hotplug operations")
Signed-off-by: Nico Pache <npache@redhat.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
For now, this selftest module can only work in x86 because of the
kprobe cmd was fixed use of x86 registers.
This patch adapted to register names under arm and riscv, So that
this module can be worked on those platform.
Link: https://lkml.kernel.org/r/20220919125629.238242-3-zouyipeng@huawei.com
Cc: <linux-riscv@lists.infradead.org>
Cc: <mingo@redhat.com>
Cc: <paul.walmsley@sifive.com>
Cc: <palmer@dabbelt.com>
Cc: <aou@eecs.berkeley.edu>
Cc: <zanussi@kernel.org>
Cc: <liaochang1@huawei.com>
Cc: <chris.zjh@huawei.com>
Fixes: 64836248dd ("tracing: Add kprobe event command generation test module")
Signed-off-by: Yipeng Zou <zouyipeng@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
With -fsanitize=kcfi, the compiler no longer renames static
functions with CONFIG_CFI_CLANG + ThinLTO. Drop the code that cleans
up the ThinLTO hash from the function names.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-19-samitolvanen@google.com
CONFIG_CFI_CLANG no longer breaks cross-module function address
equality, which makes WARN_ON_FUNCTION_MISMATCH unnecessary. Remove
the definition and switch back to WARN_ON_ONCE.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-15-samitolvanen@google.com
Switch from Clang's original forward-edge control-flow integrity
implementation to -fsanitize=kcfi, which is better suited for the
kernel, as it doesn't require LTO, doesn't use a jump table that
requires altering function references, and won't break cross-module
function address equality.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-6-samitolvanen@google.com
In preparation to switching to -fsanitize=kcfi, remove support for the
CFI module shadow that will no longer be needed.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-4-samitolvanen@google.com
The structure filter_pred and the typedef of the function used are only
referenced by trace_events_filter.c. There's no reason to have it in an
external header file. Move them into the only file they are used in.
Link: https://lkml.kernel.org/r/20220906225529.598047132@goodmis.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
In order to testing filtering and histograms via the trace event
benchmark, record the delta time of the last event as a numeric value
(currently, it just saves it within the string) so that filters and
histograms can use it.
Link: https://lkml.kernel.org/r/20220906225529.213677569@goodmis.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The sparse tool complains as follows:
kernel/trace/rv/monitors/wwnr/wwnr.c:18:19:
warning: symbol 'rv_wwnr' was not declared. Should it be static?
The `rv_wwnr` symbol is not dereferenced by other extern files,
so add static qualifier for it.
So does wip module.
Link: https://lkml.kernel.org/r/20220824034357.2014202-2-zengheng4@huawei.com
Cc: <mingo@redhat.com>
Fixes: ccc319dcb4 ("rv/monitor: Add the wwnr monitor")
Fixes: 8812d21219 ("rv/monitor: Add the wip monitor skeleton created by dot2k")
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Add the filter option to the event probe. This is useful if user wants
to derive a new event based on the condition of the original event.
E.g.
echo 'e:egroup/stat_runtime_4core sched/sched_stat_runtime \
runtime=$runtime:u32 if cpu < 4' >> ../dynamic_events
Then it can filter the events only on first 4 cores.
Note that the fields used for 'if' must be the fields in the original
events, not eprobe events.
Link: https://lkml.kernel.org/r/165932114513.2850673.2592206685744598080.stgit@devnote2
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
* Add Waiman Long as a cpuset maintainer.
* cgroup_get_from_id() could be fed a kernfs ID which doesn't point to a
cgroup directory but a knob file and then crash. Error out if the lookup
kernfs_node isn't a directory.
-----BEGIN PGP SIGNATURE-----
iIQEABYIACwWIQTfIjM1kS57o3GsC/uxYfJx3gVYGQUCYy5+yw4cdGpAa2VybmVs
Lm9yZwAKCRCxYfJx3gVYGVO/AP9yyLyH9UjRm8HOyXi0mENzVzzPUeO7x3b0lQfT
NxyOPwD+LSF+bycem1vz7YDL60DmNMHrKq+/V24UNmHm3gbr2Ag=
=kWKv
-----END PGP SIGNATURE-----
Merge tag 'cgroup-for-6.0-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
- Add Waiman Long as a cpuset maintainer
- cgroup_get_from_id() could be fed a kernfs ID which doesn't point to
a cgroup directory but a knob file and then crash. Error out if the
lookup kernfs_node isn't a directory.
* tag 'cgroup-for-6.0-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: cgroup_get_from_id() must check the looked-up kn is a directory
cpuset: Add Waiman Long as a cpuset maintainer
Just one patch to improve flush lockdep coverage.
-----BEGIN PGP SIGNATURE-----
iIQEABYIACwWIQTfIjM1kS57o3GsC/uxYfJx3gVYGQUCYy59mA4cdGpAa2VybmVs
Lm9yZwAKCRCxYfJx3gVYGQbdAP9MZIYCsJkmHshVbNcCdsUIzCvymQen7y/mCFYN
4EMArAEApCgZanJ/80Kt468IpCobaPyYhqXwDwxSVEzpYiVscgY=
=DK3F
-----END PGP SIGNATURE-----
Merge tag 'wq-for-6.0-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
"Just one patch to improve flush lockdep coverage"
* tag 'wq-for-6.0-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: don't skip lockdep work dependency in cancel_work_sync()
This merges the driver core changes in 6.0-rc7 into driver-core-next as
they are needed here as well for testing.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The implementation of strscpy() is more robust and safer.
That's now the recommended way to copy NUL terminated strings.
Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>
It could directly return 'cgroup_update_dfl_csses' to simplify code.
Signed-off-by: William Dean <williamsukatube@163.com>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
After merging 836ac87d ("cgroup: fix cgroup_get_from_id") into for-6.1, its
combination with two commits in for-6.1 - 4534dee9 ("cgroup: cgroup: Honor
caller's cgroup NS when resolving cgroup id") and fa7e439c ("cgroup:
Homogenize cgroup_get_from_id() return value") - makes the gotos in the
error handling path too ugly while not adding anything of value.
All that the gotos are saving is one extra kernfs_put() call. Let's remove
the gotos and perform error returns directly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Michal Koutný <mkoutny@suse.com>
for-6.0 has the following fix for cgroup_get_from_id().
836ac87d ("cgroup: fix cgroup_get_from_id")
which conflicts with the following two commits in for-6.1.
4534dee9 ("cgroup: cgroup: Honor caller's cgroup NS when resolving cgroup id")
fa7e439c ("cgroup: Homogenize cgroup_get_from_id() return value")
While the resolution is straightforward, the code ends up pretty ugly
afterwards. Let's pull for-6.0-fixes into for-6.1 so that the code can be
fixed up there.
Signed-off-by: Tejun Heo <tj@kernel.org>
cgroup has to be one kernfs dir, otherwise kernel panic is caused,
especially cgroup id is provide from userspace.
Reported-by: Marco Patalano <mpatalan@redhat.com>
Fixes: 6b658c4863 ("scsi: cgroup: Add cgroup_get_from_id()")
Cc: Muneendra <muneendra.kumar@broadcom.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Mukesh Ojha <quic_mojha@quicinc.com>
Cc: stable@vger.kernel.org # v5.14+
Signed-off-by: Tejun Heo <tj@kernel.org>
Add per klp_object sysfs entry "patched". It makes it easier to debug
typos in the module name.
Signed-off-by: Song Liu <song@kernel.org>
Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com>
[pmladek@suse.com: Updated kernel version when the sysfs file will be introduced]
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220902205208.3117798-2-song@kernel.org
Instead of forcing all arguments to be referenced pointers with non-zero
reg->ref_obj_id, tweak the definition of KF_TRUSTED_ARGS to mean that
only PTR_TO_BTF_ID (and socket types translated to PTR_TO_BTF_ID) have
that constraint, and require their offset to be set to 0.
The rest of pointer types are also accomodated in this definition of
trusted pointers, but with more relaxed rules regarding offsets.
The inherent meaning of setting this flag is that all kfunc pointer
arguments have a guranteed lifetime, and kernel object pointers
(PTR_TO_BTF_ID, PTR_TO_CTX) are passed in their unmodified form (with
offset 0). In general, this is not true for PTR_TO_BTF_ID as it can be
obtained using pointer walks.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/cdede0043c47ed7a357f0a915d16f9ce06a1d589.1663778601.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For a non-preallocated hash map on RT kernel, regular spinlock instead
of raw spinlock is used for bucket lock. The reason is that on RT kernel
memory allocation is forbidden under atomic context and regular spinlock
is sleepable under RT.
Now hash map has been fully converted to use bpf_map_alloc, and there
will be no synchronous memory allocation for non-preallocated hash map,
so it is safe to always use raw spinlock for bucket lock on RT. So
removing the usage of htab_use_raw_lock() and updating the comments
accordingly.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220921073826.2365800-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We got report from sysbot [1] about warnings that were caused by
bpf program attached to contention_begin raw tracepoint triggering
the same tracepoint by using bpf_trace_printk helper that takes
trace_printk_lock lock.
Call Trace:
<TASK>
? trace_event_raw_event_bpf_trace_printk+0x5f/0x90
bpf_trace_printk+0x2b/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
bpf_trace_printk+0x3f/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
bpf_trace_printk+0x3f/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
bpf_trace_printk+0x3f/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
__unfreeze_partials+0x5b/0x160
...
The can be reproduced by attaching bpf program as raw tracepoint on
contention_begin tracepoint. The bpf prog calls bpf_trace_printk
helper. Then by running perf bench the spin lock code is forced to
take slow path and call contention_begin tracepoint.
Fixing this by skipping execution of the bpf program if it's
already running, Using bpf prog 'active' field, which is being
currently used by trampoline programs for the same reason.
Moving bpf_prog_inc_misses_counter to syscall.c because
trampoline.c is compiled in just for CONFIG_BPF_JIT option.
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Reported-by: syzbot+2251879aa068ad9c960d@syzkaller.appspotmail.com
[1] https://lore.kernel.org/bpf/YxhFe3EwqchC%2FfYf@krava/T/#t
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220916071914.7156-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add the bpf_verify_pkcs7_signature() kfunc, to give eBPF security modules
the ability to check the validity of a signature against supplied data, by
using user-provided or system-provided keys as trust anchor.
The new kfunc makes it possible to enforce mandatory policies, as eBPF
programs might be allowed to make security decisions only based on data
sources the system administrator approves.
The caller should provide the data to be verified and the signature as eBPF
dynamic pointers (to minimize the number of parameters) and a bpf_key
structure containing a reference to the keyring with keys trusted for
signature verification, obtained from bpf_lookup_user_key() or
bpf_lookup_system_key().
For bpf_key structures obtained from the former lookup function,
bpf_verify_pkcs7_signature() completes the permission check deferred by
that function by calling key_validate(). key_task_permission() is already
called by the PKCS#7 code.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220920075951.929132-9-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add the bpf_lookup_user_key(), bpf_lookup_system_key() and bpf_key_put()
kfuncs, to respectively search a key with a given key handle serial number
and flags, obtain a key from a pre-determined ID defined in
include/linux/verification.h, and cleanup.
Introduce system_keyring_id_check() to validate the keyring ID parameter of
bpf_lookup_system_key().
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220920075951.929132-8-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Export bpf_dynptr_get_size(), so that kernel code dealing with eBPF dynamic
pointers can obtain the real size of data carried by this data structure.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220920075951.929132-6-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allow dynamic pointers (struct bpf_dynptr_kern *) to be specified as
parameters in kfuncs. Also, ensure that dynamic pointers passed as argument
are valid and initialized, are a pointer to the stack, and of the type
local. More dynamic pointer types can be supported in the future.
To properly detect whether a parameter is of the desired type, introduce
the stringify_struct() macro to compare the returned structure name with
the desired name. In addition, protect against structure renames, by
halting the build with BUILD_BUG_ON(), so that developers have to revisit
the code.
To check if a dynamic pointer passed to the kfunc is valid and initialized,
and if its type is local, export the existing functions
is_dynptr_reg_valid_init() and is_dynptr_type_expected().
Cc: Joanne Koong <joannelkoong@gmail.com>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220920075951.929132-5-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Move dynptr type check to is_dynptr_type_expected() from
is_dynptr_reg_valid_init(), so that callers can better determine the cause
of a negative result (dynamic pointer not valid/initialized, dynamic
pointer of the wrong type). It will be useful for example for BTF, to
restrict which dynamic pointer types can be passed to kfuncs, as initially
only the local type will be supported.
Also, splitting makes the code more readable, since checking the dynamic
pointer type is not necessarily related to validity and initialization.
Split the validity/initialization and dynamic pointer type check also in
the verifier, and adjust the expected error message in the test (a test for
an unexpected dynptr type passed to a helper cannot be added due to missing
suitable helpers, but this case has been tested manually).
Cc: Joanne Koong <joannelkoong@gmail.com>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220920075951.929132-4-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
eBPF dynamic pointers is a new feature recently added to upstream. It binds
together a pointer to a memory area and its size. The internal kernel
structure bpf_dynptr_kern is not accessible by eBPF programs in user space.
They instead see bpf_dynptr, which is then translated to the internal
kernel structure by the eBPF verifier.
The problem is that it is not possible to include at the same time the uapi
include linux/bpf.h and the vmlinux BTF vmlinux.h, as they both contain the
definition of some structures/enums. The compiler complains saying that the
structures/enums are redefined.
As bpf_dynptr is defined in the uapi include linux/bpf.h, this makes it
impossible to include vmlinux.h. However, in some cases, e.g. when using
kfuncs, vmlinux.h has to be included. The only option until now was to
include vmlinux.h and add the definition of bpf_dynptr directly in the eBPF
program source code from linux/bpf.h.
Solve the problem by using the same approach as for bpf_timer (which also
follows the same scheme with the _kern suffix for the internal kernel
structure).
Add the following line in one of the dynamic pointer helpers,
bpf_dynptr_from_mem():
BTF_TYPE_EMIT(struct bpf_dynptr);
Cc: stable@vger.kernel.org
Cc: Joanne Koong <joannelkoong@gmail.com>
Fixes: 97e03f5210 ("bpf: Add verifier support for dynptrs")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Tested-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/r/20220920075951.929132-3-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In preparation for the addition of new kfuncs, allow kfuncs defined in the
tracing subsystem to be used in LSM programs by mapping the LSM program
type to the TRACING hook.
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220920075951.929132-2-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In a prior change, we added a new BPF_MAP_TYPE_USER_RINGBUF map type which
will allow user-space applications to publish messages to a ring buffer
that is consumed by a BPF program in kernel-space. In order for this
map-type to be useful, it will require a BPF helper function that BPF
programs can invoke to drain samples from the ring buffer, and invoke
callbacks on those samples. This change adds that capability via a new BPF
helper function:
bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void *ctx,
u64 flags)
BPF programs may invoke this function to run callback_fn() on a series of
samples in the ring buffer. callback_fn() has the following signature:
long callback_fn(struct bpf_dynptr *dynptr, void *context);
Samples are provided to the callback in the form of struct bpf_dynptr *'s,
which the program can read using BPF helper functions for querying
struct bpf_dynptr's.
In order to support bpf_ringbuf_drain(), a new PTR_TO_DYNPTR register
type is added to the verifier to reflect a dynptr that was allocated by
a helper function and passed to a BPF program. Unlike PTR_TO_STACK
dynptrs which are allocated on the stack by a BPF program, PTR_TO_DYNPTR
dynptrs need not use reference tracking, as the BPF helper is trusted to
properly free the dynptr before returning. The verifier currently only
supports PTR_TO_DYNPTR registers that are also DYNPTR_TYPE_LOCAL.
Note that while the corresponding user-space libbpf logic will be added
in a subsequent patch, this patch does contain an implementation of the
.map_poll() callback for BPF_MAP_TYPE_USER_RINGBUF maps. This
.map_poll() callback guarantees that an epoll-waiting user-space
producer will receive at least one event notification whenever at least
one sample is drained in an invocation of bpf_user_ringbuf_drain(),
provided that the function is not invoked with the BPF_RB_NO_WAKEUP
flag. If the BPF_RB_FORCE_WAKEUP flag is provided, a wakeup
notification is sent even if no sample was drained.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-3-void@manifault.com
We want to support a ringbuf map type where samples are published from
user-space, to be consumed by BPF programs. BPF currently supports a
kernel -> user-space circular ring buffer via the BPF_MAP_TYPE_RINGBUF
map type. We'll need to define a new map type for user-space -> kernel,
as none of the helpers exported for BPF_MAP_TYPE_RINGBUF will apply
to a user-space producer ring buffer, and we'll want to add one or
more helper functions that would not apply for a kernel-producer
ring buffer.
This patch therefore adds a new BPF_MAP_TYPE_USER_RINGBUF map type
definition. The map type is useless in its current form, as there is no
way to access or use it for anything until we one or more BPF helpers. A
follow-on patch will therefore add a new helper function that allows BPF
programs to run callbacks on samples that are published to the ring
buffer.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-2-void@manifault.com
This has been enabled for unprivileged programs for only one kernel
release, hence the expected annoyances due to this move are low. Users
using ringbuf can stick to non-dynptr APIs. The actual use cases dynptr
is meant to serve may not make sense in unprivileged BPF programs.
Hence, gate these helpers behind CAP_BPF and limit use to privileged
BPF programs.
Fixes: 263ae152e9 ("bpf: Add bpf_dynptr_from_mem for local dynptrs")
Fixes: bc34dee65a ("bpf: Dynptr support for ring buffers")
Fixes: 13bbbfbea7 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write")
Fixes: 34d4ef5775 ("bpf: Add dynptr data slices")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220921143550.30247-1-memxor@gmail.com
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Attach flags is only valid for attached progs of this layer cgroup,
but not for effective progs. For querying with EFFECTIVE flags,
exporting attach flags does not make sense. So when effective query,
we reject prog_attach_flags array and don't need to populate it.
Also we limit attach_flags to output 0 during effective query.
Fixes: b79c9fc955 ("bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP")
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/r/20220921104604.2340580-2-pulehui@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
It could directly return 'btf_check_sec_info' to simplify code.
Signed-off-by: William Dean <williamsukatube@163.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220917084248.3649-1-williamsukatube@163.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Coccinelle reports a warning:
WARNING: use scnprintf or sprintf
This LWN article explains the rationale for this change:
https: //lwn.net/Articles/69419/
Ie. snprintf() returns what *would* be the resulting length,
while scnprintf() returns the actual length.
Adding to that, there has also been some slow migration from snprintf to scnprintf,
here's the shift in usage in the past 3.5 years, in all fs/ files:
v5.0 v6.0-rc6
--------------------------------------
snprintf() uses: 63 213
scnprintf() uses: 374 186
No intended change in behavior.
[ mingo: Improved the changelog & reviewed the usage sites. ]
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Printing this information will be helpful:
------------[ cut here ]------------
Looking for class "l2tp_sock" with key l2tp_socket_class, but found a different class "slock-AF_INET6" with the same key
WARNING: CPU: 1 PID: 14195 at kernel/locking/lockdep.c:940 look_up_lock_class+0xcc/0x140
Modules linked in:
CPU: 1 PID: 14195 Comm: a.out Not tainted 6.0.0-rc6-dirty #863
Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
RIP: 0010:look_up_lock_class+0xcc/0x140
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/bd99391e-f787-efe9-5ec6-3c6dc4c587b0@I-love.SAKURA.ne.jp
The size of cpumasks is hard-limited by compile-time parameter NR_CPUS,
but defined at boot-time when kernel parses ACPI/DT tables, and stored in
nr_cpu_ids. In many practical cases, number of CPUs for a target is known
at compile time, and can be provided with NR_CPUS.
In that case, compiler may be instructed to rely on NR_CPUS as on actual
number of CPUs, not an upper limit. It allows to optimize many cpumask
routines and significantly shrink size of the kernel image.
This patch adds FORCE_NR_CPUS option to teach the compiler to rely on
NR_CPUS and enable corresponding optimizations.
If FORCE_NR_CPUS=y, kernel will not set nr_cpu_ids at boot, but only check
that the actual number of possible CPUs is equal to NR_CPUS, and WARN if
that doesn't hold.
The new option is especially useful in embedded applications because
kernel configurations are unique for each SoC, the number of CPUs is
constant and known well, and memory limitations are typically harder.
For my 4-CPU ARM64 build with NR_CPUS=4, FORCE_NR_CPUS=y saves 46KB:
add/remove: 3/4 grow/shrink: 46/729 up/down: 652/-46952 (-46300)
Signed-off-by: Yury Norov <yury.norov@gmail.com>
- Remove the recent "unshare time namespace on vfork+exec" feature (Andrei Vagin)
-----BEGIN PGP SIGNATURE-----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=yFGx
-----END PGP SIGNATURE-----
Merge tag 'execve-v6.0-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull execve reverts from Kees Cook:
"The recent work to support time namespace unsharing turns out to have
some undesirable corner cases, so rather than allowing the API to stay
exposed for another release, it'd be best to remove it ASAP, with the
replacement getting another cycle of testing. Nothing is known to use
this yet, so no userspace breakage is expected.
For more details, see:
https://lore.kernel.org/lkml/ed418e43ad28b8688cfea2b7c90fce1c@ispras.ru
Summary:
- Remove the recent 'unshare time namespace on vfork+exec' feature
(Andrei Vagin)"
* tag 'execve-v6.0-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
Revert "fs/exec: allow to unshare a time namespace on vfork+exec"
Revert "selftests/timens: add a test for vfork+exit"
llnode could be NULL if there are new allocations after the checking of
c-free_cnt > c->high_watermark in bpf_mem_refill() and before the
calling of __llist_del_first() in free_bulk (e.g. a PREEMPT_RT kernel
or allocation in NMI context). And it will incur oops as shown below:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0
Oops: 0002 [#1] PREEMPT_RT SMP
CPU: 39 PID: 373 Comm: irq_work/39 Tainted: G W 6.0.0-rc6-rt9+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:bpf_mem_refill+0x66/0x130
......
Call Trace:
<TASK>
irq_work_single+0x24/0x60
irq_work_run_list+0x24/0x30
run_irq_workd+0x18/0x20
smpboot_thread_fn+0x13f/0x2c0
kthread+0x121/0x140
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x1f/0x30
</TASK>
Simply fixing it by checking whether or not llnode is NULL in free_bulk().
Fixes: 8d5a8011b3 ("bpf: Batch call_rcu callbacks instead of SLAB_TYPESAFE_BY_RCU.")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220919144811.3570825-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
To properly account for all refaults from file system logic, file systems
need to call psi_memstall_enter directly, so export it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lore.kernel.org/r/20220915094200.139713-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The panics in swiotlb are relics of a bygone era, some of them
inadvertently inherited from a memblock refactor, and all of them
unnecessary since they are in places that may also fail gracefully
anyway.
Convert the panics in swiotlb_init_remap() into non-fatal warnings
more consistent with the other bail-out paths there and in
swiotlb_init_late() (but don't bother trying to roll anything back,
since if anything does actually fail that early, the aim is merely to
keep going as far as possible to get more diagnostic information out
of the inevitably-dying kernel). It's not for SWIOTLB to decide that the
system is terminally compromised just because there *might* turn out to
be one or more 32-bit devices that might want to make streaming DMA
mappings, especially since we already handle the no-buffer case later
if it turns out someone did want it.
Similarly though, downgrade that panic in swiotlb_tbl_map_single(),
since even if we do get to that point it's an overly extreme reaction.
It makes little difference to the DMA API caller whether a mapping fails
because the buffer is full or because there is no buffer, and once again
it's not for SWIOTLB to presume that any particular DMA mapping is so
fundamental to the operation of the system that it must be terminal if
it could never succeed. Even if the caller handles failure by futilely
retrying forever, a single stuck thread is considerably less impactful
to the user than a needless panic.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The use of kmap_atomic() is being deprecated in favor of
kmap_local_page(), which can also be used in atomic context (including
interrupts).
Replace kmap_atomic() with kmap_local_page(). Instead of open coding
mapping, memcpy(), and un-mapping, use the memcpy_{from,to}_page() helper.
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
In preparation to support compile-time nr_cpu_ids, add a setter for
the variable.
This is a no-op for all arches.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
SMP and NR_CPUS are independent options, hence nr_cpu_ids may be
declared even if NR_CPUS == 1, which is useless.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
commit 509853f9e1 ("genirq: Provide generic_handle_irq_safe()")
addressed the problem of demultiplexing interrupt handlers which are force
threaded on PREEMPT_RT enabled kernels which means that the demultiplexed
handler is invoked with interrupts enabled which triggers a lockdep
warning due to a non-irq safe lock acquisition.
The same problem exists for the irq domain based interrupt handling via
generic_handle_domain_irq() which has been reported against the AMD
pin-ctrl driver.
Provide generic_handle_domain_irq_safe() which can used from any context.
[ tglx: Split the usage sites out and massaged changelog ]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/YnkfWFzvusFFktSt@linutronix.de
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215954
We have btf_type_str(). Use it whenever possible in btf.c, instead of
"btf_kind_str[BTF_INFO_KIND(t->info)]".
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Link: https://lore.kernel.org/r/20220916202800.31421-1-yepeilin.cs@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
x86 will shortly start using -fpatchable-function-entry for purposes
other than ftrace, make sure the __patchable_function_entry section
isn't merged in the mcount_loc section.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220903131154.420467-2-jolsa@kernel.org
The documentation for find_vpid() clearly states:
"Must be called with the tasklist_lock or rcu_read_lock() held."
Presently we do neither for find_vpid() instance in bpf_task_fd_query().
Add proper rcu_read_lock/unlock() to fix the issue.
Fixes: 41bdc4b40e ("bpf: introduce bpf subcommand BPF_TASK_FD_QUERY")
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220912133855.1218900-1-lee@kernel.org
The internal functions are marked with __sched already, let's do the same
for external functions too so that we can skip them in the stack trace.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220909000803.4181857-1-namhyung@kernel.org
Make the region inside the rwsem_write_trylock non preemptible.
We observe RT task is hogging CPU when trying to acquire rwsem lock
which was acquired by a kworker task but before the rwsem owner was set.
Here is the scenario:
1. CFS task (affined to a particular CPU) takes rwsem lock.
2. CFS task gets preempted by a RT task before setting owner.
3. RT task (FIFO) is trying to acquire the lock, but spinning until
RT throttling happens for the lock as the lock was taken by CFS task.
This patch attempts to fix the above issue by disabling preemption
until owner is set for the lock. While at it also fix the issues
at the places where rwsem_{set,clear}_owner() are called.
This also adds lockdep annotation of preemption disable in
rwsem_{set,clear}_owner() on Peter Z. suggestion.
Signed-off-by: Gokul krishna Krishnakumar <quic_gokukris@quicinc.com>
Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/1662661467-24203-1-git-send-email-quic_mojha@quicinc.com
sched_nr_migrate_break is set to a fix value and never changes so we can
replace it by a define SCHED_NR_MIGRATE_BREAK.
Also, we adjust SCHED_NR_MIGRATE_BREAK to be aligned with the init value
of sysctl_sched_nr_migrate which can be init to different values.
Then, use SCHED_NR_MIGRATE_BREAK to init sysctl_sched_nr_migrate.
The behavior stays unchanged unless you modify sysctl_sched_nr_migrate
trough debugfs.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220825122726.20819-3-vincent.guittot@linaro.org
During load balance, we try at most env->loop_max time to move a task.
But it can happen that the loop_max LRU tasks (ie tail of
the cfs_tasks list) can't be moved to dst_cpu because of affinity.
In this case, loop in the list until we found at least one.
The maximum of detached tasks remained the same as before.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220825122726.20819-2-vincent.guittot@linaro.org
BPF_PTR_POISON was added in commit c0a5a21c25 ("bpf: Allow storing
referenced kptr in map") to denote a bpf_func_proto btf_id which the
verifier will replace with a dynamically-determined btf_id at verification
time.
This patch adds verifier 'poison' functionality to BPF_PTR_POISON in
order to prepare for expanded use of the value to poison ret- and
arg-btf_id in ongoing work, namely rbtree and linked list patchsets
[0, 1]. Specifically, when the verifier checks helper calls, it assumes
that BPF_PTR_POISON'ed ret type will be replaced with a valid type before
- or in lieu of - the default ret_btf_id logic. Similarly for arg btf_id.
If poisoned btf_id reaches default handling block for either, consider
this a verifier internal error and fail verification. Otherwise a helper
w/ poisoned btf_id but no verifier logic replacing the type will cause a
crash as the invalid pointer is dereferenced.
Also move BPF_PTR_POISON to existing include/linux/posion.h header and
remove unnecessary shift.
[0]: lore.kernel.org/bpf/20220830172759.4069786-1-davemarchevsky@fb.com
[1]: lore.kernel.org/bpf/20220904204145.3089-1-memxor@gmail.com
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220912154544.1398199-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This reverts commit 133e2d3e81.
Alexey pointed out a few undesirable side effects of the reverted change.
First, it doesn't take into account that CLONE_VFORK can be used with
CLONE_THREAD. Second, a child process doesn't enter a target time name-space,
if its parent dies before the child calls exec. It happens because the parent
clears vfork_done.
Eric W. Biederman suggests installing a time namespace as a task gets a new mm.
It includes all new processes cloned without CLONE_VM and all tasks that call
exec(). This is an user API change, but we think there aren't users that depend
on the old behavior.
It is too late to make such changes in this release, so let's roll back
this patch and introduce the right one in the next release.
Cc: Alexey Izbyshev <izbyshev@ispras.ru>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220913102551.1121611-3-avagin@google.com
If the perf_event has PERF_SAMPLE_CALLCHAIN, BPF can use it for stack trace.
The problematic cases like PEBS and IBS already handled in the PMU driver and
they filled the callchain info in the sample data. For others, we can call
perf_callchain() before the BPF handler.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220908214104.3851807-2-namhyung@kernel.org
So that it can call perf_callchain() only if needed. Historically it used
__PERF_SAMPLE_CALLCHAIN_EARLY but we can do that with sample_flags in the
struct perf_sample_data.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220908214104.3851807-1-namhyung@kernel.org
-----BEGIN PGP SIGNATURE-----
iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAmMeQ2keHHRvcnZhbGRz
QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGYRMH+gLNHiGirGZlm2GQ
tKaZQUy7MiXuIP0hGDonDIIIAmIVhnjm9MDG8KT4W8AvEd7ukncyYqJfwWeWQPhP
4mZcf6l3Z8Ke+qiaFpXpMPCxTyWcln1ox0EoNx2g9gdPxZntaRuuaTQVljUfTiey
aVPHxve8ip3G7jDoJnuLSxESOqWxkb8v/SshBP1E5bF5BZ+cgZRqq7FNigFqxjbk
wF29K09BVOPjdgkSvY/b0/SnL5KlSdMAv+FrPcJNGivcdIPgf/qJks5cI2HRUo7o
CpKgbcLorCVyD+d+zLonJBwIy3arbmKD8JqYnfdTSIqVOUqHXWUDfeydsH32u1Gu
lPSI2Hw=
=7LTL
-----END PGP SIGNATURE-----
Merge 6.0-rc5 into driver-core-next
We need the driver core and debugfs changes in this branch.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In account_global_scheduler_latency(), when we don't find the matching
latency_record we try to select one which is unused in
latency_record[MAXLR], but the condition will skip the last one.
if (i >= MAXLR-1)
Fix that.
Link: https://lkml.kernel.org/r/20220903135233.5225-1-wuchi.zero@gmail.com
Signed-off-by: wuchi <wuchi.zero@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foudation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Print the machine hardware name (UTS_MACHINE) in /proc/sys/kernel/arch.
This helps people who debug kernel with initramfs with minimal environment
(i.e. without coreutils or even busybox) or allow to open sysfs file
instead of run 'uname -m' in high level languages.
Link: https://lkml.kernel.org/r/20220901194403.3819-1-pvorel@suse.cz
Signed-off-by: Petr Vorel <pvorel@suse.cz>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: David Sterba <dsterba@suse.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The code to parse option string "schedule/sleep/kvm" of cmdline in
function profile_setup is redundant, so simplify that.
Link: https://lkml.kernel.org/r/20220901003121.53597-1-wuchi.zero@gmail.com
Signed-off-by: wuchi <wuchi.zero@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foudation.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If register_kprobe() fails, the new attr is not added to the list yet, so
it should call fei_attr_free() intstead.
Link: https://lkml.kernel.org/r/20220826073337.2085798-3-yangyingliang@huawei.com
Fixes: 4b1a29a7f5 ("error-injection: Support fault injection framework")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Refactor the error handling of register_kprobe() to improve readability.
No functional change.
Link: https://lkml.kernel.org/r/20220826073337.2085798-2-yangyingliang@huawei.com
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use memdup_user_nul() helper instead of open-coding to simplify the code.
Link: https://lkml.kernel.org/r/20220826073337.2085798-1-yangyingliang@huawei.com
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use atomic_try_cmpxchg instead of atomic_cmpxchg (*ptr, old, new) == old
in cpu_wait_death and cpu_report_death. x86 CMPXCHG instruction returns
success in ZF flag, so this change saves a compare after cmpxchg (and
related move instruction in front of cmpxchg). Also, atomic_try_cmpxchg
implicitly assigns old *ptr value to "old" when cmpxchg fails, enabling
further code simplifications.
No functional change intended.
Link: https://lkml.kernel.org/r/20220825145603.5811-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
task_work_add, task_work_cancel_match and task_work_run. x86 CMPXCHG
instruction returns success in ZF flag, so this change saves a compare
after cmpxchg (and related move instruction in front of cmpxchg).
Also, atomic_try_cmpxchg implicitly assigns old *ptr value to "old"
when cmpxchg fails, enabling further code simplifications.
The patch avoids extra memory read in case cmpxchg fails.
Link: https://lkml.kernel.org/r/20220823152632.4517-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kmap() is being deprecated in favor of kmap_local_page().
There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap's pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.
With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and are still valid.
Since its use in kexec_core.c is safe everywhere, it should be preferred.
Therefore, replace kmap() with kmap_local_page() in kexec_core.c.
Tested on a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.
Link: https://lkml.kernel.org/r/20220821182519.9483-1-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Attempting to get a crash dump out of a debug PREEMPT_RT kernel via an NMI
panic() doesn't work. The cause of that lies in the PREEMPT_RT definition
of mutex_trylock():
if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task()))
return 0;
This prevents an nmi_panic() from executing the main body of
__crash_kexec() which does the actual kexec into the kdump kernel. The
warning and return are explained by:
6ce47fd961 ("rtmutex: Warn if trylock is called from hard/softirq context")
[...]
The reasons for this are:
1) There is a potential deadlock in the slowpath
2) Another cpu which blocks on the rtmutex will boost the task
which allegedly locked the rtmutex, but that cannot work
because the hard/softirq context borrows the task context.
Furthermore, grabbing the lock isn't NMI safe, so do away with kexec_mutex
and replace it with an atomic variable. This is somewhat overzealous as
*some* callsites could keep using a mutex (e.g. the sysfs-facing ones
like crash_shrink_memory()), but this has the benefit of involving a
single unified lock and preventing any future NMI-related surprises.
Tested by triggering NMI panics via:
$ echo 1 > /proc/sys/kernel/panic_on_unrecovered_nmi
$ echo 1 > /proc/sys/kernel/unknown_nmi_panic
$ echo 1 > /proc/sys/kernel/panic
$ ipmitool power diag
Link: https://lkml.kernel.org/r/20220630223258.4144112-3-vschneid@redhat.com
Fixes: 6ce47fd961 ("rtmutex: Warn if trylock is called from hard/softirq context")
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "kexec, panic: Making crash_kexec() NMI safe", v4.
This patch (of 2):
Most acquistions of kexec_mutex are done via mutex_trylock() - those were
a direct "translation" from:
8c5a1cf0ad ("kexec: use a mutex for locking rather than xchg()")
there have however been two additions since then that use mutex_lock():
crash_get_memory_size() and crash_shrink_memory().
A later commit will replace said mutex with an atomic variable, and
locking operations will become atomic_cmpxchg(). Rather than having those
mutex_lock() become while (atomic_cmpxchg(&lock, 0, 1)), turn them into
trylocks that can return -EBUSY on acquisition failure.
This does halve the printable size of the crash kernel, but that's still
neighbouring 2G for 32bit kernels which should be ample enough.
Link: https://lkml.kernel.org/r/20220630223258.4144112-1-vschneid@redhat.com
Link: https://lkml.kernel.org/r/20220630223258.4144112-2-vschneid@redhat.com
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The promotion hot threshold is workload and system configuration
dependent. So in this patch, a method to adjust the hot threshold
automatically is implemented. The basic idea is to control the number of
the candidate promotion pages to match the promotion rate limit. If the
hint page fault latency of a page is less than the hot threshold, we will
try to promote the page, and the page is called the candidate promotion
page.
If the number of the candidate promotion pages in the statistics interval
is much more than the promotion rate limit, the hot threshold will be
decreased to reduce the number of the candidate promotion pages.
Otherwise, the hot threshold will be increased to increase the number of
the candidate promotion pages.
To make the above method works, in each statistics interval, the total
number of the pages to check (on which the hint page faults occur) and the
hot/cold distribution need to be stable. Because the page tables are
scanned linearly in NUMA balancing, but the hot/cold distribution isn't
uniform along the address usually, the statistics interval should be
larger than the NUMA balancing scan period. So in the patch, the max scan
period is used as statistics interval and it works well in our tests.
Link: https://lkml.kernel.org/r/20220713083954.34196-4-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: osalvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In NUMA balancing memory tiering mode, if there are hot pages in slow
memory node and cold pages in fast memory node, we need to promote/demote
hot/cold pages between the fast and cold memory nodes.
A choice is to promote/demote as fast as possible. But the CPU cycles and
memory bandwidth consumed by the high promoting/demoting throughput will
hurt the latency of some workload because of accessing inflating and slow
memory bandwidth contention.
A way to resolve this issue is to restrict the max promoting/demoting
throughput. It will take longer to finish the promoting/demoting. But
the workload latency will be better. This is implemented in this patch as
the page promotion rate limit mechanism.
The number of the candidate pages to be promoted to the fast memory node
via NUMA balancing is counted, if the count exceeds the limit specified by
the users, the NUMA balancing promotion will be stopped until the next
second.
A new sysctl knob kernel.numa_balancing_promote_rate_limit_MBps is added
for the users to specify the limit.
Link: https://lkml.kernel.org/r/20220713083954.34196-3-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: osalvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "memory tiering: hot page selection", v4.
To optimize page placement in a memory tiering system with NUMA balancing,
the hot pages in the slow memory nodes need to be identified.
Essentially, the original NUMA balancing implementation selects the mostly
recently accessed (MRU) pages to promote. But this isn't a perfect
algorithm to identify the hot pages. Because the pages with quite low
access frequency may be accessed eventually given the NUMA balancing page
table scanning period could be quite long (e.g. 60 seconds). So in this
patchset, we implement a new hot page identification algorithm based on
the latency between NUMA balancing page table scanning and hint page
fault. Which is a kind of mostly frequently accessed (MFU) algorithm.
In NUMA balancing memory tiering mode, if there are hot pages in slow
memory node and cold pages in fast memory node, we need to promote/demote
hot/cold pages between the fast and cold memory nodes.
A choice is to promote/demote as fast as possible. But the CPU cycles and
memory bandwidth consumed by the high promoting/demoting throughput will
hurt the latency of some workload because of accessing inflating and slow
memory bandwidth contention.
A way to resolve this issue is to restrict the max promoting/demoting
throughput. It will take longer to finish the promoting/demoting. But
the workload latency will be better. This is implemented in this patchset
as the page promotion rate limit mechanism.
The promotion hot threshold is workload and system configuration
dependent. So in this patchset, a method to adjust the hot threshold
automatically is implemented. The basic idea is to control the number of
the candidate promotion pages to match the promotion rate limit.
We used the pmbench memory accessing benchmark tested the patchset on a
2-socket server system with DRAM and PMEM installed. The test results are
as follows,
pmbench score promote rate
(accesses/s) MB/s
------------- ------------
base 146887704.1 725.6
hot selection 165695601.2 544.0
rate limit 162814569.8 165.2
auto adjustment 170495294.0 136.9
From the results above,
With hot page selection patch [1/3], the pmbench score increases about
12.8%, and promote rate (overhead) decreases about 25.0%, compared with
base kernel.
With rate limit patch [2/3], pmbench score decreases about 1.7%, and
promote rate decreases about 69.6%, compared with hot page selection
patch.
With threshold auto adjustment patch [3/3], pmbench score increases about
4.7%, and promote rate decrease about 17.1%, compared with rate limit
patch.
Baolin helped to test the patchset with MySQL on a machine which contains
1 DRAM node (30G) and 1 PMEM node (126G).
sysbench /usr/share/sysbench/oltp_read_write.lua \
......
--tables=200 \
--table-size=1000000 \
--report-interval=10 \
--threads=16 \
--time=120
The tps can be improved about 5%.
This patch (of 3):
To optimize page placement in a memory tiering system with NUMA balancing,
the hot pages in the slow memory node need to be identified. Essentially,
the original NUMA balancing implementation selects the mostly recently
accessed (MRU) pages to promote. But this isn't a perfect algorithm to
identify the hot pages. Because the pages with quite low access frequency
may be accessed eventually given the NUMA balancing page table scanning
period could be quite long (e.g. 60 seconds). The most frequently
accessed (MFU) algorithm is better.
So, in this patch we implemented a better hot page selection algorithm.
Which is based on NUMA balancing page table scanning and hint page fault
as follows,
- When the page tables of the processes are scanned to change PTE/PMD
to be PROT_NONE, the current time is recorded in struct page as scan
time.
- When the page is accessed, hint page fault will occur. The scan
time is gotten from the struct page. And The hint page fault
latency is defined as
hint page fault time - scan time
The shorter the hint page fault latency of a page is, the higher the
probability of their access frequency to be higher. So the hint page
fault latency is a better estimation of the page hot/cold.
It's hard to find some extra space in struct page to hold the scan time.
Fortunately, we can reuse some bits used by the original NUMA balancing.
NUMA balancing uses some bits in struct page to store the page accessing
CPU and PID (referring to page_cpupid_xchg_last()). Which is used by the
multi-stage node selection algorithm to avoid to migrate pages shared
accessed by the NUMA nodes back and forth. But for pages in the slow
memory node, even if they are shared accessed by multiple NUMA nodes, as
long as the pages are hot, they need to be promoted to the fast memory
node. So the accessing CPU and PID information are unnecessary for the
slow memory pages. We can reuse these bits in struct page to record the
scan time. For the fast memory pages, these bits are used as before.
For the hot threshold, the default value is 1 second, which works well in
our performance test. All pages with hint page fault latency < hot
threshold will be considered hot.
It's hard for users to determine the hot threshold. So we don't provide a
kernel ABI to set it, just provide a debugfs interface for advanced users
to experiment. We will continue to work on a hot threshold automatic
adjustment mechanism.
The downside of the above method is that the response time to the workload
hot spot changing may be much longer. For example,
- A previous cold memory area becomes hot
- The hint page fault will be triggered. But the hint page fault
latency isn't shorter than the hot threshold. So the pages will
not be promoted.
- When the memory area is scanned again, maybe after a scan period,
the hint page fault latency measured will be shorter than the hot
threshold and the pages will be promoted.
To mitigate this, if there are enough free space in the fast memory node,
the hot threshold will not be used, all pages will be promoted upon the
hint page fault for fast response.
Thanks Zhong Jiang reported and tested the fix for a bug when disabling
memory tiering mode dynamically.
Link: https://lkml.kernel.org/r/20220713083954.34196-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20220713083954.34196-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Wei Xu <weixugc@google.com>
Cc: osalvador <osalvador@suse.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
