Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758039Ab3D2SER (ORCPT ); Mon, 29 Apr 2013 14:04:17 -0400 Received: from oproxy6-pub.bluehost.com ([67.222.54.6]:46314 "HELO oproxy6-pub.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1756904Ab3D2SEQ (ORCPT ); Mon, 29 Apr 2013 14:04:16 -0400 Message-ID: <1367258649.8833.19.camel@Wailaba2> Subject: [PATCH v3 1/3] posix_timers: do not account group_exec_runtime for dying autoreaped tasks From: Olivier Langlois To: Peter Zijlstra , Ingo Molnar , Thomas Gleixner , schwidefsky@de.ibm.com, Steven Rostedt , Frederic Weisbecker Cc: KOSAKI Motohiro , LKML Date: Mon, 29 Apr 2013 14:04:09 -0400 Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.8.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Identified-User: {5686:box610.bluehost.com:olivierl:olivierlanglois.net} {sentby:smtp auth 173.178.230.31 authed with olivier@olivierlanglois.net} Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1702 Lines: 46 Forbids the cputimer to drift ahead of its process clock by blocking its update when a tick occurs while a autoreaping task is currently in do_exit() between the call to release_task() and its final call to schedule(). Any task stats update after having called release_task() will be lost because they are added to the global process stats located in the signal struct from release_task(). Signed-off-by: Olivier Langlois --- kernel/sched/fair.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7a33e59..52d7b10 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -708,7 +708,15 @@ static void update_curr(struct cfs_rq *cfs_rq) trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); cpuacct_charge(curtask, delta_exec); - account_group_exec_runtime(curtask, delta_exec); + /* + * Do not update the cputimer if the task is already released by + * release_task(). + * + * it would preferable to defer the autoreap release_task + * after the last context switch but harder to do. + */ + if (likely(curtask->sighand)) + account_group_exec_runtime(curtask, delta_exec); } account_cfs_rq_runtime(cfs_rq, delta_exec); -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/