From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755940AbZKTV2a (ORCPT ); Fri, 20 Nov 2009 16:28:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755067AbZKTV23 (ORCPT ); Fri, 20 Nov 2009 16:28:29 -0500 Received: from casper.infradead.org ([85.118.1.10]:48327 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755047AbZKTV20 (ORCPT ); Fri, 20 Nov 2009 16:28:26 -0500 Message-Id: <20091120212509.102316434@chello.nl> References: <20091120211942.676891948@chello.nl> User-Agent: quilt/0.46-1 Date: Fri, 20 Nov 2009 22:19:54 +0100 From: Peter Zijlstra To: Paul Mackerras , Ingo Molnar , Peter Zijlstra Cc: linux-kernel@vger.kernel.org Subject: [PATCH 12/15] perf: fix time locking Content-Disposition: inline; filename=perf-time-5.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- kernel/perf_event.c | 9 +++++++++ 1 file changed, 9 insertions(+) Index: linux-2.6/kernel/perf_event.c =================================================================== --- linux-2.6.orig/kernel/perf_event.c +++ linux-2.6/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_e 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); --