From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752312AbcI3MCy (ORCPT ); Fri, 30 Sep 2016 08:02:54 -0400 Received: from terminus.zytor.com ([198.137.202.10]:44994 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750703AbcI3MCo (ORCPT ); Fri, 30 Sep 2016 08:02:44 -0400 Date: Fri, 30 Sep 2016 05:01:54 -0700 From: tip-bot for Vincent Guittot Message-ID: Cc: torvalds@linux-foundation.org, hpa@zytor.com, vincent.guittot@linaro.org, efault@gmx.de, peterz@infradead.org, linux-kernel@vger.kernel.org, mingo@kernel.org, tglx@linutronix.de Reply-To: torvalds@linux-foundation.org, hpa@zytor.com, vincent.guittot@linaro.org, efault@gmx.de, peterz@infradead.org, linux-kernel@vger.kernel.org, mingo@kernel.org, tglx@linutronix.de In-Reply-To: <1473666472-13749-8-git-send-email-vincent.guittot@linaro.org> References: <1473666472-13749-8-git-send-email-vincent.guittot@linaro.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/core: Fix incorrect utilization accounting when switching to fair class Git-Commit-ID: a399d233078edbba7cf7902a6d080100cdf75636 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 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: a399d233078edbba7cf7902a6d080100cdf75636 Gitweb: http://git.kernel.org/tip/a399d233078edbba7cf7902a6d080100cdf75636 Author: Vincent Guittot AuthorDate: Mon, 12 Sep 2016 09:47:52 +0200 Committer: Ingo Molnar CommitDate: Fri, 30 Sep 2016 11:03:27 +0200 sched/core: Fix incorrect utilization accounting when switching to fair class When a task switches to fair scheduling class, the period between now and the last update of its utilization is accounted as running time whatever happened during this period. This incorrect accounting applies to the task and also to the task group branch. When changing the property of a running task like its list of allowed CPUs or its scheduling class, we follow the sequence: - dequeue task - put task - change the property - set task as current task - enqueue task The end of the sequence doesn't follow the normal sequence (as per __schedule()) which is: - enqueue a task - then set the task as current task. This incorrectordering is the root cause of incorrect utilization accounting. Update the sequence to follow the right one: - dequeue task - put task - change the property - enqueue task - set task as current task Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: linaro-kernel@lists.linaro.org Cc: pjt@google.com Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/1473666472-13749-8-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 9411545..2b5e150 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1109,10 +1109,10 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) p->sched_class->set_cpus_allowed(p, new_mask); - if (running) - p->sched_class->set_curr_task(rq); if (queued) enqueue_task(rq, p, ENQUEUE_RESTORE); + if (running) + p->sched_class->set_curr_task(rq); } /* @@ -3707,10 +3707,10 @@ void rt_mutex_setprio(struct task_struct *p, int prio) p->prio = prio; - if (running) - p->sched_class->set_curr_task(rq); if (queued) enqueue_task(rq, p, queue_flag); + if (running) + p->sched_class->set_curr_task(rq); check_class_changed(rq, p, prev_class, oldprio); out_unlock: @@ -4263,8 +4263,6 @@ change: prev_class = p->sched_class; __setscheduler(rq, p, attr, pi); - if (running) - p->sched_class->set_curr_task(rq); if (queued) { /* * We enqueue to tail when the priority of a task is @@ -4275,6 +4273,8 @@ change: enqueue_task(rq, p, queue_flags); } + if (running) + p->sched_class->set_curr_task(rq); check_class_changed(rq, p, prev_class, oldprio); preempt_disable(); /* avoid rq from going away on us */ @@ -5439,10 +5439,10 @@ void sched_setnuma(struct task_struct *p, int nid) p->numa_preferred_nid = nid; - if (running) - p->sched_class->set_curr_task(rq); if (queued) enqueue_task(rq, p, ENQUEUE_RESTORE); + if (running) + p->sched_class->set_curr_task(rq); task_rq_unlock(rq, p, &rf); } #endif /* CONFIG_NUMA_BALANCING */ @@ -7949,10 +7949,10 @@ void sched_move_task(struct task_struct *tsk) sched_change_group(tsk, TASK_MOVE_GROUP); - if (unlikely(running)) - tsk->sched_class->set_curr_task(rq); if (queued) enqueue_task(rq, tsk, ENQUEUE_RESTORE | ENQUEUE_MOVE); + if (unlikely(running)) + tsk->sched_class->set_curr_task(rq); task_rq_unlock(rq, tsk, &rf); }