diff options
| author |   Peter Zijlstra <peterz@infradead.org> | 2016-03-10 15:39:24 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2016-03-21 09:08:14 +0100 |
| commit | 1e02cd40f15190b78fcc6b3f50c952fb4028e9a5 (patch) | |
| tree | 7825f267ca1c1f9fb50d4c52612ae531661e406c /kernel | |
| parent | x86/oprofile/nmi: Add missing hotplug FROZEN handling (diff) | |
| download | linux-dev-1e02cd40f15190b78fcc6b3f50c952fb4028e9a5.tar.xz linux-dev-1e02cd40f15190b78fcc6b3f50c952fb4028e9a5.zip | |
perf/core: Fix the unthrottle logic
Its possible to IOC_PERIOD while the event is throttled, this would
re-start the event and the next tick would then try to unthrottle it,
and find the event wasn't actually stopped anymore.
This would tickle a WARN in the x86-pmu code which isn't expecting to
start a !stopped event.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
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: dvyukov@google.com
Cc: oleg@redhat.com
Cc: panand@redhat.com
Cc: sasha.levin@oracle.com
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/20160310143924.GR6356@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 712570dddacd..d39477390415 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4210,6 +4210,14 @@ static void __perf_event_period(struct perf_event *event, active = (event->state == PERF_EVENT_STATE_ACTIVE); if (active) { perf_pmu_disable(ctx->pmu); + /* + * We could be throttled; unthrottle now to avoid the tick + * trying to unthrottle while we already re-started the event. + */ + if (event->hw.interrupts == MAX_INTERRUPTS) { + event->hw.interrupts = 0; + perf_log_throttle(event, 1); + } event->pmu->stop(event, PERF_EF_UPDATE); } |