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perf: Fix time locking 

Most sites updating ctx->time and event times do so under
ctx->lock, make sure they all do.

This was made possible by removing the __perf_event_read() call
from __perf_event_sync_stat(), which already had this lock
taken.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212509.102316434@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
hifive-unleashed-5.1
Peter Zijlstra 2009-11-20 22:19:54 +01:00 committed by Ingo Molnar
parent 58e5ad1de3
commit 2b8988c9f7
1 changed files with 9 additions and 0 deletions
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9
kernel/perf_event.c
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@ -1526,8 +1526,11 @@ static void __perf_event_read(void *info)
if (ctx->task && cpuctx->task_ctx != ctx)
return;
spin_lock(&ctx->lock);
update_context_time(ctx);
update_event_times(event);
spin_unlock(&ctx->lock);
event->pmu->read(event);
}
@ -1541,7 +1544,13 @@ static u64 perf_event_read(struct perf_event *event)
smp_call_function_single(event->oncpu,
__perf_event_read, event, 1);
} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
struct perf_event_context *ctx = event->ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->lock, flags);
update_context_time(ctx);
update_event_times(event);
spin_unlock_irqrestore(&ctx->lock, flags);
}
return atomic64_read(&event->count);