Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752906AbaJWXFE (ORCPT ); Thu, 23 Oct 2014 19:05:04 -0400 Received: from mail-pd0-f181.google.com ([209.85.192.181]:56051 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751718AbaJWXFC (ORCPT ); Thu, 23 Oct 2014 19:05:02 -0400 Message-ID: <54498998.40707@gmail.com> Date: Fri, 24 Oct 2014 07:04:56 +0800 From: Wanpeng Li User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Juri Lelli , Kirill Tkhai , Peter Zijlstra CC: Kirill Tkhai , "linux-kernel@vger.kernel.org" , Ingo Molnar , Juri Lelli Subject: Re: [PATCH v2 2/3] sched/dl: Cleanup prio_changed_dl() References: <20140930210412.5258.35299.stgit@localhost> <20140930210428.5258.32223.stgit@localhost> <20141002093600.GC2849@worktop.programming.kicks-ass.net> <1412243541.20287.28.camel@tkhai> <544688A1.7010403@arm.com> In-Reply-To: <544688A1.7010403@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 10/22/14, 12:24 AM, Juri Lelli: > Hi Kirill, > > On 02/10/14 10:52, Kirill Tkhai wrote: >> В Чт, 02/10/2014 в 11:36 +0200, Peter Zijlstra пишет: >>> On Wed, Oct 01, 2014 at 01:04:35AM +0400, Kirill Tkhai wrote: >>>> From: Kirill Tkhai >>>> >>>> rq->curr task can't be in "dequeued" state in prio_changed_dl(). >>>> (The only place we can have that is __schedule()). So, we delete >>>> rq->curr check. >>> the CBS timer can throttle it right? >> Yeah, it's better to check for on_dl_rq(): >> >> [PATCH]sched/dl: Cleanup prio_changed_dl() >> >> rq->curr task can't be in "dequeued" state in prio_changed_dl(). >> (The only place we can have that is __schedule()). So, we delete >> rq->curr check. >> >> We shouldn't do balancing if deadline task is throttled too. >> >> Also delete "else" branch which is dead code (switched_to_dl() >> is not interested in dequeued tasks and we are not interested >> in balancing in this case). >> > So, I agree that calling switched_to_dl() makes little sense, > but don't we have to deal with updates to not running tasks as > in rt.c? Something like this maybe? > > From 75ee75a5fd76526baaed3ba8a58f3ff7daa89cd6 Mon Sep 17 00:00:00 2001 > From: Juri Lelli > Date: Tue, 21 Oct 2014 17:15:15 +0100 > Subject: [PATCH] sched/deadline: cleanup prio_changed_dl() > > --- > kernel/sched/deadline.c | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index 28d6088..1e62e31 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -1661,7 +1661,10 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p) > static void prio_changed_dl(struct rq *rq, struct task_struct *p, > int oldprio) > { > - if (task_on_rq_queued(p) || rq->curr == p) { > + if (!on_dl_rq(&p->dl)) I'm not sure if this should be task_on_rq_queued() check. All check_class_changed() callsites dequeue entity if task_on_rq_queued() is true which leads to on_dl_rq(&p->dl) always return false. Regards, Wanpeng Li > + return; > + > + if (rq->curr == p) { > #ifdef CONFIG_SMP > /* > * This might be too much, but unfortunately > @@ -1688,8 +1691,15 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p, > */ > resched_curr(rq); > #endif /* CONFIG_SMP */ > - } else > - switched_to_dl(rq, p); > + } else { > + /* > + * This task is not running, so if its deadline is > + * now more imminent than that of the current running > + * task then reschedule. > + */ > + if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline)) > + resched_curr(rq); > + } > } > > const struct sched_class dl_sched_class = { -- 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/