From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754036Ab1KRXdT (ORCPT ); Fri, 18 Nov 2011 18:33:19 -0500 Received: from terminus.zytor.com ([198.137.202.10]:53321 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750760Ab1KRXdR (ORCPT ); Fri, 18 Nov 2011 18:33:17 -0500 Date: Fri, 18 Nov 2011 15:32:58 -0800 From: tip-bot for Gleb Natapov Message-ID: Cc: linux-kernel@vger.kernel.org, gleb@redhat.com, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, gleb@redhat.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <20111023171033.GI17571@redhat.com> References: <20111023171033.GI17571@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/urgent] perf: Do not set task_ctx pointer in cpuctx if there are no events in the context Git-Commit-ID: 1d5f003f5a964711853514b04ddc872eec0fdc7b X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (terminus.zytor.com [127.0.0.1]); Fri, 18 Nov 2011 15:33:04 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 1d5f003f5a964711853514b04ddc872eec0fdc7b Gitweb: http://git.kernel.org/tip/1d5f003f5a964711853514b04ddc872eec0fdc7b Author: Gleb Natapov AuthorDate: Sun, 23 Oct 2011 19:10:33 +0200 Committer: Ingo Molnar CommitDate: Mon, 14 Nov 2011 13:01:21 +0100 perf: Do not set task_ctx pointer in cpuctx if there are no events in the context Do not set task_ctx pointer during sched_in if there are no events associated with the context. Otherwise if during task execution total number of events in the system will become zero perf_event_context_sched_out() will not be called and cpuctx->task_ctx will be left with a stale value. Signed-off-by: Gleb Natapov Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20111023171033.GI17571@redhat.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 0e8457d..b0c1186 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2173,7 +2173,8 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx, perf_event_sched_in(cpuctx, ctx, task); - cpuctx->task_ctx = ctx; + if (ctx->nr_events) + cpuctx->task_ctx = ctx; perf_pmu_enable(ctx->pmu); perf_ctx_unlock(cpuctx, ctx);