From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754080Ab1ASLaC (ORCPT ); Wed, 19 Jan 2011 06:30:02 -0500 Received: from canuck.infradead.org ([134.117.69.58]:37004 "EHLO canuck.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753636Ab1ASLaA convert rfc822-to-8bit (ORCPT ); Wed, 19 Jan 2011 06:30:00 -0500 Subject: Re: Bug in scheduler when using rt_mutex From: Peter Zijlstra To: Yong Zhang Cc: samu.p.onkalo@nokia.com, mingo@elte.hu, "linux-kernel@vger.kernel.org" , tglx In-Reply-To: <1295433498.30950.1482.camel@laptop> References: <1295275365.12840.13.camel@kolo> <1295280032.30950.128.camel@laptop> <1295339012.11678.35.camel@kolo> <1295357746.30950.681.camel@laptop> <1295430276.30950.1414.camel@laptop> <1295433498.30950.1482.camel@laptop> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Wed, 19 Jan 2011 12:30:32 +0100 Message-ID: <1295436632.30950.1542.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2011-01-19 at 11:38 +0100, Peter Zijlstra wrote: > Hrm, I think the to bit is not needed with the from thing in place, the > enqueue from _setprio will already have added min_vruntime Would lead to something like this: --- Index: linux-2.6/kernel/sched.c =================================================================== --- linux-2.6.orig/kernel/sched.c +++ linux-2.6/kernel/sched.c @@ -8108,6 +8108,8 @@ EXPORT_SYMBOL(__might_sleep); #ifdef CONFIG_MAGIC_SYSRQ static void normalize_task(struct rq *rq, struct task_struct *p) { + struct sched_class *prev_class = p->sched_class; + int old_prio = p->prio; int on_rq; on_rq = p->se.on_rq; @@ -8118,6 +8120,8 @@ static void normalize_task(struct rq *rq activate_task(rq, p, 0); resched_task(rq->curr); } + + check_class_changed(rq, p, prev_class, old_prio, task_current(rq, p)); } void normalize_rt_tasks(void) Index: linux-2.6/kernel/sched_fair.c =================================================================== --- linux-2.6.orig/kernel/sched_fair.c +++ linux-2.6/kernel/sched_fair.c @@ -4066,11 +4066,30 @@ static void prio_changed_fair(struct rq check_preempt_curr(rq, p, 0); } +static void +switched_from_fair(struct rq *rq, struct task_struct *p, int running) +{ + struct sched_entity *se = &p->se; + struct cfs_rq *cfs_rq = cfs_rq_of(se); + + /* + * Ensure the task's vruntime is normalized, so that when its + * switched back to the fair class the enqueue_entity(.flags=0) will + * do the right thing. + * + * If it was on_rq, then the dequeue_entity(.flags=0) will already + * have normalized the vruntime, if it was !on_rq, then only when + * the task is sleeping will it still have non-normalized vruntime. + */ + if (!se->on_rq && p->state != TASK_RUNNING) + se->vruntime -= cfs_rq->min_vruntime; +} + /* * We switched to the sched_fair class. */ -static void switched_to_fair(struct rq *rq, struct task_struct *p, - int running) +static void +switched_to_fair(struct rq *rq, struct task_struct *p, int running) { /* * We were most likely switched from sched_rt, so @@ -4163,6 +4182,7 @@ static const struct sched_class fair_sch .task_fork = task_fork_fair, .prio_changed = prio_changed_fair, + .switched_from = switched_from_fair, .switched_to = switched_to_fair, .get_rr_interval = get_rr_interval_fair,