Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753560Ab2HMQyU (ORCPT ); Mon, 13 Aug 2012 12:54:20 -0400 Received: from terminus.zytor.com ([198.137.202.10]:33521 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753498Ab2HMQxZ (ORCPT ); Mon, 13 Aug 2012 12:53:25 -0400 Date: Mon, 13 Aug 2012 09:53:06 -0700 From: tip-bot for Mike Galbraith Message-ID: Cc: linux-kernel@vger.kernel.org, mgalbraith@suse.de, hpa@zytor.com, mingo@kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, mgalbraith@suse.de, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de In-Reply-To: <1344051854.6739.19.camel@marge.simpson.net> References: <1344051854.6739.19.camel@marge.simpson.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] sched: Fix migration thread runtime bogosity Git-Commit-ID: 8f6189684eb4e85e6c593cd710693f09c944450a X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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]); Mon, 13 Aug 2012 09:53:11 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3111 Lines: 90 Commit-ID: 8f6189684eb4e85e6c593cd710693f09c944450a Gitweb: http://git.kernel.org/tip/8f6189684eb4e85e6c593cd710693f09c944450a Author: Mike Galbraith AuthorDate: Sat, 4 Aug 2012 05:44:14 +0200 Committer: Thomas Gleixner CommitDate: Mon, 13 Aug 2012 18:41:55 +0200 sched: Fix migration thread runtime bogosity Make stop scheduler class do the same accounting as other classes, Migration threads can be caught in the act while doing exec balancing, leading to the below due to use of unmaintained ->se.exec_start. The load that triggered this particular instance was an apparently out of control heavily threaded application that does system monitoring in what equated to an exec bomb, with one of the VERY frequently migrated tasks being ps. %CPU PID USER CMD 99.3 45 root [migration/10] 97.7 53 root [migration/12] 97.0 57 root [migration/13] 90.1 49 root [migration/11] 89.6 65 root [migration/15] 88.7 17 root [migration/3] 80.4 37 root [migration/8] 78.1 41 root [migration/9] 44.2 13 root [migration/2] Signed-off-by: Mike Galbraith Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1344051854.6739.19.camel@marge.simpson.net Signed-off-by: Thomas Gleixner --- kernel/sched/stop_task.c | 22 +++++++++++++++++++++- 1 files changed, 21 insertions(+), 1 deletions(-) diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c index 7b386e8..da5eb5b 100644 --- a/kernel/sched/stop_task.c +++ b/kernel/sched/stop_task.c @@ -27,8 +27,10 @@ static struct task_struct *pick_next_task_stop(struct rq *rq) { struct task_struct *stop = rq->stop; - if (stop && stop->on_rq) + if (stop && stop->on_rq) { + stop->se.exec_start = rq->clock_task; return stop; + } return NULL; } @@ -52,6 +54,21 @@ static void yield_task_stop(struct rq *rq) static void put_prev_task_stop(struct rq *rq, struct task_struct *prev) { + struct task_struct *curr = rq->curr; + u64 delta_exec; + + delta_exec = rq->clock_task - curr->se.exec_start; + if (unlikely((s64)delta_exec < 0)) + delta_exec = 0; + + schedstat_set(curr->se.statistics.exec_max, + max(curr->se.statistics.exec_max, delta_exec)); + + curr->se.sum_exec_runtime += delta_exec; + account_group_exec_runtime(curr, delta_exec); + + curr->se.exec_start = rq->clock_task; + cpuacct_charge(curr, delta_exec); } static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued) @@ -60,6 +77,9 @@ static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued) static void set_curr_task_stop(struct rq *rq) { + struct task_struct *stop = rq->stop; + + stop->se.exec_start = rq->clock_task; } static void switched_to_stop(struct rq *rq, struct task_struct *p) -- 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/