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Arnaldo Carvalho de Melo c5dfd78eb7 perf core: Allow setting up max frame stack depth via sysctl
The default remains 127, which is good for most cases, and not even hit
most of the time, but then for some cases, as reported by Brendan, 1024+
deep frames are appearing on the radar for things like groovy, ruby.

And in some workloads putting a _lower_ cap on this may make sense. One
that is per event still needs to be put in place tho.

The new file is:

  # cat /proc/sys/kernel/perf_event_max_stack
  127

Chaging it:

  # echo 256 > /proc/sys/kernel/perf_event_max_stack
  # cat /proc/sys/kernel/perf_event_max_stack
  256

But as soon as there is some event using callchains we get:

  # echo 512 > /proc/sys/kernel/perf_event_max_stack
  -bash: echo: write error: Device or resource busy
  #

Because we only allocate the callchain percpu data structures when there
is a user, which allows for changing the max easily, its just a matter
of having no callchain users at that point.

Reported-and-Tested-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/20160426002928.GB16708@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-04-27 10:20:39 -03:00
..
bpf perf core: Allow setting up max frame stack depth via sysctl 2016-04-27 10:20:39 -03:00
configs
debug mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings 2016-02-22 08:51:37 +01:00
events perf core: Allow setting up max frame stack depth via sysctl 2016-04-27 10:20:39 -03:00
gcov gcov: use within_module() helper. 2015-12-04 22:46:25 +01:00
irq kernel/...: convert pr_warning to pr_warn 2016-03-22 15:36:02 -07:00
livepatch livepatch/module: remove livepatch module notifier 2016-03-17 09:45:10 +01:00
locking locking/lockdep: Fix print_collision() unused warning 2016-04-04 11:41:34 +02:00
power Power management and ACPI material for v4.6-rc1, part 2 2016-03-24 22:59:58 -07:00
printk printk: add clear_idx symbol to vmcoreinfo 2016-03-17 15:09:34 -07:00
rcu kernel: add kcov code coverage 2016-03-22 15:36:02 -07:00
sched locking/atomic, sched: Unexport fetch_or() 2016-03-29 11:52:11 +02:00
time timers/nohz: Convert tick dependency mask to atomic_t 2016-03-29 11:52:11 +02:00
trace Linux 4.6-rc3 2016-04-13 08:57:03 +02:00
.gitignore
acct.c
async.c async: export current_is_async() 2015-11-19 17:51:48 +01:00
audit.c Merge branch 'stable-4.6' of git://git.infradead.org/users/pcmoore/audit 2016-03-19 17:52:49 -07:00
audit.h security: Make inode argument of inode_getsecid non-const 2015-12-24 11:09:39 -05:00
audit_fsnotify.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
audit_tree.c audit: audit_tree_match can be boolean 2015-11-04 08:23:51 -05:00
audit_watch.c Merge branch 'stable-4.6' of git://git.infradead.org/users/pcmoore/audit 2016-03-19 17:52:49 -07:00
auditfilter.c audit: Fix typo in comment 2016-02-08 11:25:39 -05:00
auditsc.c auditsc: for seccomp events, log syscall compat state using in_compat_syscall 2016-03-22 15:36:02 -07:00
backtracetest.c
bounds.c
capability.c
cgroup.c Merge branch 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2016-03-21 10:05:13 -07:00
cgroup_freezer.c cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends 2015-12-03 10:24:08 -05:00
cgroup_pids.c cgroup_pids: fix a typo. 2015-12-14 14:54:37 -05:00
compat.c
configs.c
context_tracking.c context_tracking: Switch to new static_branch API 2015-11-24 09:56:43 +01:00
cpu.c cpu/hotplug: Document states better 2016-03-12 20:57:38 +01:00
cpu_pm.c
cpuset.c Merge branch 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2016-03-21 10:05:13 -07:00
crash_dump.c
cred.c kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
delayacct.c kmemcg: account certain kmem allocations to memcg 2016-01-14 16:00:49 -08:00
dma.c
elfcore.c
exec_domain.c
exit.c oom: clear TIF_MEMDIE after oom_reaper managed to unmap the address space 2016-03-25 16:37:42 -07:00
extable.c
fork.c kernel: add kcov code coverage 2016-03-22 15:36:02 -07:00
freezer.c
futex.c futex: Replace barrier() in unqueue_me() with READ_ONCE() 2016-03-08 17:04:02 +01:00
futex_compat.c ptrace: use fsuid, fsgid, effective creds for fs access checks 2016-01-20 17:09:18 -08:00
groups.c
hung_task.c kernel/hung_task.c: use timeout diff when timeout is updated 2016-03-22 15:36:02 -07:00
irq_work.c treewide: Remove old email address 2015-11-23 09:44:58 +01:00
jump_label.c treewide: Remove old email address 2015-11-23 09:44:58 +01:00
kallsyms.c kallsyms: add support for relative offsets in kallsyms address table 2016-03-15 16:55:16 -07:00
kcmp.c ptrace: use fsuid, fsgid, effective creds for fs access checks 2016-01-20 17:09:18 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kernel: add kcov code coverage 2016-03-22 15:36:02 -07:00
kexec.c kexec: set KEXEC_TYPE_CRASH before sanity_check_segment_list() 2016-01-20 17:09:18 -08:00
kexec_core.c kexec: Set IORESOURCE_SYSTEM_RAM for System RAM 2016-01-30 09:49:57 +01:00
kexec_file.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2016-03-17 11:33:45 -07:00
kexec_internal.h kexec: move some memembers and definitions within the scope of CONFIG_KEXEC_FILE 2016-01-20 17:09:18 -08:00
kmod.c
kprobes.c
ksysfs.c rcu: Remove TINY_RCU bloat from pointless boot parameters 2015-12-07 16:59:37 -08:00
kthread.c
latencytop.c sched/debug: Make schedstats a runtime tunable that is disabled by default 2016-02-09 11:54:23 +01:00
Makefile kernel: add kcov code coverage 2016-03-22 15:36:02 -07:00
membarrier.c
memremap.c memremap: add MEMREMAP_WC flag 2016-03-22 15:36:02 -07:00
module-internal.h
module.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching 2016-03-17 21:46:32 -07:00
module_signing.c X.509: Make algo identifiers text instead of enum 2016-03-03 21:49:27 +00:00
notifier.c
nsproxy.c cgroup: introduce cgroup namespaces 2016-02-16 13:04:58 -05:00
padata.c
panic.c panic: change nmi_panic from macro to function 2016-03-22 15:36:02 -07:00
params.c Nothing exciting, minor tweaks and cleanups. 2015-11-09 15:53:39 -08:00
pid.c Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-01-31 15:44:04 -08:00
pid_namespace.c
profile.c profile: hide unused functions when !CONFIG_PROC_FS 2016-03-22 15:36:02 -07:00
ptrace.c ptrace: change __ptrace_unlink() to clear ->ptrace under ->siglock 2016-03-22 15:36:02 -07:00
range.c
reboot.c
relay.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
resource.c /proc/iomem: only expose physical resource addresses to privileged users 2016-04-14 12:56:09 -07:00
seccomp.c seccomp: check in_compat_syscall, not is_compat_task, in strict mode 2016-03-22 15:36:02 -07:00
signal.c kernel/signal.c: add compile-time check for __ARCH_SI_PREAMBLE_SIZE 2016-03-22 15:36:02 -07:00
smp.c Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-15 13:50:29 -07:00
smpboot.c cpu/hotplug: Unpark smpboot threads from the state machine 2016-03-01 20:36:56 +01:00
smpboot.h cpu/hotplug: Create hotplug threads 2016-03-01 20:36:56 +01:00
softirq.c arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
stacktrace.c
stop_machine.c kernel/stop_machine.c: remove CONFIG_SMP dependencies 2016-01-16 11:17:24 -08:00
sys.c timer: convert timer_slack_ns from unsigned long to u64 2016-03-17 15:09:34 -07:00
sys_ni.c vfs: add copy_file_range syscall and vfs helper 2015-12-01 14:00:53 -05:00
sysctl.c perf core: Allow setting up max frame stack depth via sysctl 2016-04-27 10:20:39 -03:00
sysctl_binary.c fs/coredump: prevent fsuid=0 dumps into user-controlled directories 2016-03-22 15:36:02 -07:00
task_work.c
taskstats.c
test_kprobes.c
torture.c
tracepoint.c kernel/...: convert pr_warning to pr_warn 2016-03-22 15:36:02 -07:00
tsacct.c time, acct: Drop irq save & restore from __acct_update_integrals() 2016-02-29 09:53:09 +01:00
uid16.c
up.c
user-return-notifier.c
user.c
user_namespace.c kernel/*: switch to memdup_user_nul() 2016-01-04 10:27:55 -05:00
utsname.c
utsname_sysctl.c
watchdog.c watchdog: don't run proc_watchdog_update if new value is same as old 2016-03-17 15:09:34 -07:00
workqueue.c Merge branch 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2016-03-18 20:05:39 -07:00
workqueue_internal.h sched/core: Get rid of 'cpu' argument in wq_worker_sleeping() 2016-03-02 10:28:47 -05:00