From 2b8988c9f7defe319cffe0cd362a7cd356c86f62 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 20 Nov 2009 22:19:54 +0100 Subject: [PATCH] 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 Cc: Paul Mackerras LKML-Reference: <20091120212509.102316434@chello.nl> Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 028619dd6d0..fdfae888a67 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -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); -- 2.41.0