linux-stable.git/kernel/events/core.c, branch v6.13.2

perf/core: Save raw sample data conditionally based on sample type

2025-02-08T09:00:57+00:00

[ Upstream commit b9c44b91476b67327a521568a854babecc4070ab ]

Currently, space for raw sample data is always allocated within sample
records for both BPF output and tracepoint events. This leads to unused
space in sample records when raw sample data is not requested.

This patch enforces checking sample type of an event in
perf_sample_save_raw_data(). So raw sample data will only be saved if
explicitly requested, reducing overhead when it is not needed.

Fixes: 0a9081cf0a11 ("perf/core: Add perf_sample_save_raw_data() helper")
Signed-off-by: Yabin Cui 
Signed-off-by: Ingo Molnar 
Reviewed-by: Ian Rogers 
Acked-by: Namhyung Kim 
Link: https://lore.kernel.org/r/20240515193610.2350456-2-yabinc@google.com
Signed-off-by: Sasha Levin

Merge tag 'mm-nonmm-stable-2024-11-24-02-05' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-11-26T00:09:48+00:00

Pull non-MM updates from Andrew Morton:

 - The series "resource: A couple of cleanups" from Andy Shevchenko
   performs some cleanups in the resource management code

 - The series "Improve the copy of task comm" from Yafang Shao addresses
   possible race-induced overflows in the management of
   task_struct.comm[]

 - The series "Remove unnecessary header includes from
   {tools/}lib/list_sort.c" from Kuan-Wei Chiu adds some cleanups and a
   small fix to the list_sort library code and to its selftest

 - The series "Enhance min heap API with non-inline functions and
   optimizations" also from Kuan-Wei Chiu optimizes and cleans up the
   min_heap library code

 - The series "nilfs2: Finish folio conversion" from Ryusuke Konishi
   finishes off nilfs2's folioification

 - The series "add detect count for hung tasks" from Lance Yang adds
   more userspace visibility into the hung-task detector's activity

 - Apart from that, singelton patches in many places - please see the
   individual changelogs for details

* tag 'mm-nonmm-stable-2024-11-24-02-05' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (71 commits)
  gdb: lx-symbols: do not error out on monolithic build
  kernel/reboot: replace sprintf() with sysfs_emit()
  lib: util_macros_kunit: add kunit test for util_macros.h
  util_macros.h: fix/rework find_closest() macros
  Improve consistency of '#error' directive messages
  ocfs2: fix uninitialized value in ocfs2_file_read_iter()
  hung_task: add docs for hung_task_detect_count
  hung_task: add detect count for hung tasks
  dma-buf: use atomic64_inc_return() in dma_buf_getfile()
  fs/proc/kcore.c: fix coccinelle reported ERROR instances
  resource: avoid unnecessary resource tree walking in __region_intersects()
  ocfs2: remove unused errmsg function and table
  ocfs2: cluster: fix a typo
  lib/scatterlist: use sg_phys() helper
  checkpatch: always parse orig_commit in fixes tag
  nilfs2: convert metadata aops from writepage to writepages
  nilfs2: convert nilfs_recovery_copy_block() to take a folio
  nilfs2: convert nilfs_page_count_clean_buffers() to take a folio
  nilfs2: remove nilfs_writepage
  nilfs2: convert checkpoint file to be folio-based
  ...

Merge tag 'perf-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-11-19T21:34:06+00:00

Pull performance events updates from Ingo Molnar:
 "Uprobes:
    - Add BPF session support (Jiri Olsa)
    - Switch to RCU Tasks Trace flavor for better performance (Andrii
      Nakryiko)
    - Massively increase uretprobe SMP scalability by SRCU-protecting
      the uretprobe lifetime (Andrii Nakryiko)
    - Kill xol_area->slot_count (Oleg Nesterov)

  Core facilities:
    - Implement targeted high-frequency profiling by adding the ability
      for an event to "pause" or "resume" AUX area tracing (Adrian
      Hunter)

  VM profiling/sampling:
    - Correct perf sampling with guest VMs (Colton Lewis)

  New hardware support:
    - x86/intel: Add PMU support for Intel ArrowLake-H CPUs (Dapeng Mi)

  Misc fixes and enhancements:
    - x86/intel/pt: Fix buffer full but size is 0 case (Adrian Hunter)
    - x86/amd: Warn only on new bits set (Breno Leitao)
    - x86/amd/uncore: Avoid a false positive warning about snprintf
      truncation in amd_uncore_umc_ctx_init (Jean Delvare)
    - uprobes: Re-order struct uprobe_task to save some space
      (Christophe JAILLET)
    - x86/rapl: Move the pmu allocation out of CPU hotplug (Kan Liang)
    - x86/rapl: Clean up cpumask and hotplug (Kan Liang)
    - uprobes: Deuglify xol_get_insn_slot/xol_free_insn_slot paths (Oleg
      Nesterov)"

* tag 'perf-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
  perf/core: Correct perf sampling with guest VMs
  perf/x86: Refactor misc flag assignments
  perf/powerpc: Use perf_arch_instruction_pointer()
  perf/core: Hoist perf_instruction_pointer() and perf_misc_flags()
  perf/arm: Drop unused functions
  uprobes: Re-order struct uprobe_task to save some space
  perf/x86/amd/uncore: Avoid a false positive warning about snprintf truncation in amd_uncore_umc_ctx_init
  perf/x86/intel: Do not enable large PEBS for events with aux actions or aux sampling
  perf/x86/intel/pt: Add support for pause / resume
  perf/core: Add aux_pause, aux_resume, aux_start_paused
  perf/x86/intel/pt: Fix buffer full but size is 0 case
  uprobes: SRCU-protect uretprobe lifetime (with timeout)
  uprobes: allow put_uprobe() from non-sleepable softirq context
  perf/x86/rapl: Clean up cpumask and hotplug
  perf/x86/rapl: Move the pmu allocation out of CPU hotplug
  uprobe: Add support for session consumer
  uprobe: Add data pointer to consumer handlers
  perf/x86/amd: Warn only on new bits set
  uprobes: fold xol_take_insn_slot() into xol_get_insn_slot()
  uprobes: kill xol_area->slot_count
  ...

Merge tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2024-11-18T20:24:06+00:00

Pull 'struct fd' class updates from Al Viro:
 "The bulk of struct fd memory safety stuff

  Making sure that struct fd instances are destroyed in the same scope
  where they'd been created, getting rid of reassignments and passing
  them by reference, converting to CLASS(fd{,_pos,_raw}).

  We are getting very close to having the memory safety of that stuff
  trivial to verify"

* tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
  deal with the last remaing boolean uses of fd_file()
  css_set_fork(): switch to CLASS(fd_raw, ...)
  memcg_write_event_control(): switch to CLASS(fd)
  assorted variants of irqfd setup: convert to CLASS(fd)
  do_pollfd(): convert to CLASS(fd)
  convert do_select()
  convert vfs_dedupe_file_range().
  convert cifs_ioctl_copychunk()
  convert media_request_get_by_fd()
  convert spu_run(2)
  switch spufs_calls_{get,put}() to CLASS() use
  convert cachestat(2)
  convert do_preadv()/do_pwritev()
  fdget(), more trivial conversions
  fdget(), trivial conversions
  privcmd_ioeventfd_assign(): don't open-code eventfd_ctx_fdget()
  o2hb_region_dev_store(): avoid goto around fdget()/fdput()
  introduce "fd_pos" class, convert fdget_pos() users to it.
  fdget_raw() users: switch to CLASS(fd_raw)
  convert vmsplice() to CLASS(fd)
  ...

perf/core: Correct perf sampling with guest VMs

2024-11-14T09:40:01+00:00

Previously any PMU overflow interrupt that fired while a VCPU was
loaded was recorded as a guest event whether it truly was or not. This
resulted in nonsense perf recordings that did not honor
perf_event_attr.exclude_guest and recorded guest IPs where it should
have recorded host IPs.

Rework the sampling logic to only record guest samples for events with
exclude_guest = 0. This way any host-only events with exclude_guest
set will never see unexpected guest samples. The behaviour of events
with exclude_guest = 0 is unchanged.

Note that events configured to sample both host and guest may still
misattribute a PMI that arrived in the host as a guest event depending
on KVM arch and vendor behavior.

Signed-off-by: Colton Lewis 
Signed-off-by: Ingo Molnar 
Reviewed-by: Oliver Upton 
Acked-by: Mark Rutland 
Acked-by: Kan Liang 
Cc: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Namhyung Kim 
Link: https://lore.kernel.org/r/20241113190156.2145593-6-coltonlewis@google.com

perf/core: Hoist perf_instruction_pointer() and perf_misc_flags()

2024-11-14T09:40:01+00:00

For clarity, rename the arch-specific definitions of these functions
to perf_arch_* to denote they are arch-specifc. Define the
generic-named functions in one place where they can call the
arch-specific ones as needed.

Signed-off-by: Colton Lewis 
Signed-off-by: Ingo Molnar 
Reviewed-by: Oliver Upton 
Acked-by: Thomas Richter 
Acked-by: Mark Rutland 
Acked-by: Madhavan Srinivasan 
Acked-by: Kan Liang 
Link: https://lore.kernel.org/r/20241113190156.2145593-3-coltonlewis@google.com

perf/core: update min_heap_callbacks to use default builtin swap

2024-11-06T01:12:35+00:00

After introducing the default builtin swap implementation, update the
min_heap_callbacks to replace the swp function pointer with NULL.  This
change allows the min heap to directly utilize the builtin swap,
simplifying the code.

Link: https://lkml.kernel.org/r/20241020040200.939973-6-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu 
Cc: Adrian Hunter 
Cc: Arnaldo Carvalho de Melo 
Cc: Ching-Chun (Jim) Huang 
Cc: Coly Li 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Jonathan Corbet 
Cc: Kent Overstreet 
Cc: "Liang, Kan" 
Cc: Mark Rutland 
Cc: Matthew Sakai 
Cc: Matthew Wilcox (Oracle) 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton

lib/min_heap: introduce non-inline versions of min heap API functions

2024-11-06T01:12:34+00:00

Patch series "Enhance min heap API with non-inline functions and
optimizations", v2.

Add non-inline versions of the min heap API functions in lib/min_heap.c
and updates all users outside of kernel/events/core.c to use these
non-inline versions.  To mitigate the performance impact of indirect
function calls caused by the non-inline versions of the swap and compare
functions, a builtin swap has been introduced that swaps elements based on
their size.  Additionally, it micro-optimizes the efficiency of the min
heap by pre-scaling the counter, following the same approach as in
lib/sort.c.  Documentation for the min heap API has also been added to the
core-api section.


This patch (of 10):

All current min heap API functions are marked with '__always_inline'. 
However, as the number of users increases, inlining these functions
everywhere leads to a increase in kernel size.

In performance-critical paths, such as when perf events are enabled and
min heap functions are called on every context switch, it is important to
retain the inline versions for optimal performance.  To balance this, the
original inline functions are kept, and additional non-inline versions of
the functions have been added in lib/min_heap.c.

Link: https://lkml.kernel.org/r/20241020040200.939973-1-visitorckw@gmail.com
Link: https://lore.kernel.org/20240522161048.8d8bbc7b153b4ecd92c50666@linux-foundation.org
Link: https://lkml.kernel.org/r/20241020040200.939973-2-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu 
Suggested-by: Andrew Morton 
Cc: Adrian Hunter 
Cc: Arnaldo Carvalho de Melo 
Cc: Ching-Chun (Jim) Huang 
Cc: Coly Li 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Jonathan Corbet 
Cc: Kent Overstreet 
Cc: Kuan-Wei Chiu 
Cc: "Liang, Kan" 
Cc: Mark Rutland 
Cc: Matthew Sakai 
Cc: Matthew Wilcox (Oracle) 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton

perf/core: Add aux_pause, aux_resume, aux_start_paused

2024-11-05T11:55:43+00:00

Hardware traces, such as instruction traces, can produce a vast amount of
trace data, so being able to reduce tracing to more specific circumstances
can be useful.

The ability to pause or resume tracing when another event happens, can do
that.

Add ability for an event to "pause" or "resume" AUX area tracing.

Add aux_pause bit to perf_event_attr to indicate that, if the event
happens, the associated AUX area tracing should be paused. Ditto
aux_resume. Do not allow aux_pause and aux_resume to be set together.

Add aux_start_paused bit to perf_event_attr to indicate to an AUX area
event that it should start in a "paused" state.

Add aux_paused to struct hw_perf_event for AUX area events to keep track of
the "paused" state. aux_paused is initialized to aux_start_paused.

Add PERF_EF_PAUSE and PERF_EF_RESUME modes for ->stop() and ->start()
callbacks. Call as needed, during __perf_event_output(). Add
aux_in_pause_resume to struct perf_buffer to prevent races with the NMI
handler. Pause/resume in NMI context will miss out if it coincides with
another pause/resume.

To use aux_pause or aux_resume, an event must be in a group with the AUX
area event as the group leader.

Example (requires Intel PT and tools patches also):

 $ perf record --kcore -e intel_pt/aux-action=start-paused/k,syscalls:sys_enter_newuname/aux-action=resume/,syscalls:sys_exit_newuname/aux-action=pause/ uname
 Linux
 [ perf record: Woken up 1 times to write data ]
 [ perf record: Captured and wrote 0.043 MB perf.data ]
 $ perf script --call-trace
 uname   30805 [000] 24001.058782799: name: 0x7ffc9c1865b0
 uname   30805 [000] 24001.058784424:  psb offs: 0
 uname   30805 [000] 24001.058784424:  cbr: 39 freq: 3904 MHz (139%)
 uname   30805 [000] 24001.058784629: ([kernel.kallsyms])        debug_smp_processor_id
 uname   30805 [000] 24001.058784629: ([kernel.kallsyms])        __x64_sys_newuname
 uname   30805 [000] 24001.058784629: ([kernel.kallsyms])            down_read
 uname   30805 [000] 24001.058784629: ([kernel.kallsyms])                __cond_resched
 uname   30805 [000] 24001.058784629: ([kernel.kallsyms])                preempt_count_add
 uname   30805 [000] 24001.058784629: ([kernel.kallsyms])                    in_lock_functions
 uname   30805 [000] 24001.058784629: ([kernel.kallsyms])                preempt_count_sub
 uname   30805 [000] 24001.058784629: ([kernel.kallsyms])            up_read
 uname   30805 [000] 24001.058784629: ([kernel.kallsyms])                preempt_count_add
 uname   30805 [000] 24001.058784838: ([kernel.kallsyms])                    in_lock_functions
 uname   30805 [000] 24001.058784838: ([kernel.kallsyms])                preempt_count_sub
 uname   30805 [000] 24001.058784838: ([kernel.kallsyms])            _copy_to_user
 uname   30805 [000] 24001.058784838: ([kernel.kallsyms])        syscall_exit_to_user_mode
 uname   30805 [000] 24001.058784838: ([kernel.kallsyms])            syscall_exit_work
 uname   30805 [000] 24001.058784838: ([kernel.kallsyms])                perf_syscall_exit
 uname   30805 [000] 24001.058784838: ([kernel.kallsyms])                    debug_smp_processor_id
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                    perf_trace_buf_alloc
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                        perf_swevent_get_recursion_context
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                            debug_smp_processor_id
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                        debug_smp_processor_id
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                    perf_tp_event
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                        perf_trace_buf_update
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                            tracing_gen_ctx_irq_test
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                        perf_swevent_event
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                            __perf_event_account_interrupt
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                                __this_cpu_preempt_check
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                            perf_event_output_forward
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                                perf_event_aux_pause
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                                    ring_buffer_get
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                                        __rcu_read_lock
 uname   30805 [000] 24001.058785046: ([kernel.kallsyms])                                        __rcu_read_unlock
 uname   30805 [000] 24001.058785254: ([kernel.kallsyms])                                    pt_event_stop
 uname   30805 [000] 24001.058785254: ([kernel.kallsyms])                                        debug_smp_processor_id
 uname   30805 [000] 24001.058785254: ([kernel.kallsyms])                                        debug_smp_processor_id
 uname   30805 [000] 24001.058785254: ([kernel.kallsyms])                                        native_write_msr
 uname   30805 [000] 24001.058785463: ([kernel.kallsyms])                                        native_write_msr
 uname   30805 [000] 24001.058785639: 0x0

Signed-off-by: Adrian Hunter 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: James Clark 
Link: https://lkml.kernel.org/r/20241022155920.17511-3-adrian.hunter@intel.com

fdget(), trivial conversions

2024-11-03T06:28:06+00:00

fdget() is the first thing done in scope, all matching fdput() are
immediately followed by leaving the scope.

Reviewed-by: Christian Brauner 
Signed-off-by: Al Viro