Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965573Ab3FUCuf (ORCPT ); Thu, 20 Jun 2013 22:50:35 -0400 Received: from mail-la0-f46.google.com ([209.85.215.46]:42568 "EHLO mail-la0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965335Ab3FUCue (ORCPT ); Thu, 20 Jun 2013 22:50:34 -0400 MIME-Version: 1.0 In-Reply-To: <51C3BCE1.1080405@gmail.com> References: <1370589652-24549-1-git-send-email-alex.shi@intel.com> <1370589652-24549-5-git-send-email-alex.shi@intel.com> <51BF2E37.5040400@intel.com> <51C318D6.4090601@gmail.com> <51C3BCE1.1080405@gmail.com> Date: Fri, 21 Jun 2013 10:50:32 +0800 Message-ID: Subject: Re: [patch v8 4/9] sched: fix slept time double counting in enqueue entity From: Lei Wen To: Alex Shi Cc: Paul Turner , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Andrew Morton , Borislav Petkov , Namhyung Kim , Mike Galbraith , Morten Rasmussen , Vincent Guittot , Preeti U Murthy , Viresh Kumar , LKML , Mel Gorman , Rik van Riel , Michael Wang , Jason Low , Changlong Xie , sgruszka@redhat.com, =?ISO-8859-1?Q?Fr=E9d=E9ric_Weisbecker?= Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3522 Lines: 109 Alex, On Fri, Jun 21, 2013 at 10:39 AM, Alex Shi wrote: > On 06/21/2013 10:30 AM, Lei Wen wrote: >> Hi Alex, >> >> On Thu, Jun 20, 2013 at 10:59 PM, Alex Shi wrote: >>> On 06/20/2013 10:46 AM, Lei Wen wrote: >>>> >>>> >>>> But here I have a question, there is another usage of __synchronzie_entity_decay >>>> in current kernel, in the switched_from_fair function. >>>> >>>> If task being frequently switched between rt and fair class, would it >>>> also bring the >>>> redundant issue? Do we need patch like below? >>>> >>>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >>>> index b5408e1..9640c66 100644 >>>> --- a/kernel/sched/fair.c >>>> +++ b/kernel/sched/fair.c >>>> @@ -5856,7 +5856,7 @@ static void switched_from_fair(struct rq *rq, >>>> struct task_struct *p) >>>> */ >>>> if (p->se.avg.decay_count) { >>>> struct cfs_rq *cfs_rq = cfs_rq_of(&p->se); >>>> - se->avg.last_runnable_update += >>>> + p->se.avg.last_runnable_update += >>> >>> what tree does this patch base on? >> >> I create the patch based on v3.9 kernel. >> If it is ok, I could create a formal one based on latest kernel. > > In the linus tree, the first commit which introduced > __synchronize_entity_decay(&p->se) here is > 9ee474f55664ff63111c843099d365e7ecffb56f > + > +#if defined(CONFIG_FAIR_GROUP_SCHED) && defined(CONFIG_SMP) > + /* > + * Remove our load from contribution when we leave sched_fair > + * and ensure we don't carry in an old decay_count if we > + * switch back. > + */ > + if (p->se.avg.decay_count) { > + struct cfs_rq *cfs_rq = cfs_rq_of(&p->se); > + __synchronize_entity_decay(&p->se); > + subtract_blocked_load_contrib(cfs_rq, > + p->se.avg.load_avg_contrib); > + } > +#endif > } > > And it is never changed from then on. So your code must based on a > incorrect kernel. please do a double check. I see your point... I made the mistake that update the wrong patch... Please help check this one. commit 5fc3d5c74f8359ef382d9a20ffe657ffc237c109 Author: Lei Wen Date: Thu Jun 20 10:43:59 2013 +0800 sched: fix potential twice decay issue Signed-off-by: Lei Wen diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c61a614..9640c66 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5856,7 +5856,8 @@ static void switched_from_fair(struct rq *rq, struct task_struct *p) */ if (p->se.avg.decay_count) { struct cfs_rq *cfs_rq = cfs_rq_of(&p->se); - __synchronize_entity_decay(&p->se); + p->se.avg.last_runnable_update += + __synchronize_entity_decay(&p->se); subtract_blocked_load_contrib(cfs_rq, p->se.avg.load_avg_contrib); } Thanks, Lei >> >> Thanks, >> Lei >> >>>> __synchronize_entity_decay(&p->se); >>>> subtract_blocked_load_contrib(cfs_rq, >>>> p->se.avg.load_avg_contrib); >>> >>> >>> -- >>> Thanks >>> Alex > > > -- > Thanks > Alex -- 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/