From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756808Ab1FAOXB (ORCPT ); Wed, 1 Jun 2011 10:23:01 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:34602 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756117Ab1FAOW7 (ORCPT ); Wed, 1 Jun 2011 10:22:59 -0400 X-Authority-Analysis: v=1.1 cv=yMxAJ7W7nAoPh8ZdbvCArpG6pAdHwgpzIvOq8QbMesM= c=1 sm=0 a=cWu3orRm09UA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=pGLkceISAAAA:8 a=P-zH6Fbi6VzdvBoGX5QA:9 a=Az-tnAt17RxsUB6xRE8A:7 a=PUjeQqilurYA:10 a=MSl-tDqOz04A:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Subject: Re: [PATCH] sched: remove resetting exec_start in put_prev_task_rt() From: Steven Rostedt To: Hillf Danton Cc: LKML , Mike Galbraith , Yong Zhang , Peter Zijlstra , Ingo Molnar In-Reply-To: References: Content-Type: text/plain; charset="ISO-8859-15" Date: Wed, 01 Jun 2011 10:22:57 -0400 Message-ID: <1306938177.10135.20.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2011-06-01 at 22:03 +0800, Hillf Danton wrote: > Resetting exec_start, after updated in update_curr_rt(), could open window for > messing up the subsequent computations of delta_exec of the given task. The domain scheduling was mostly done by Peter, but when you make a change like this, you need to explain it better than this. I really have no idea what you mean in this change log. Please give an example of how this "open window" can mess up the subsequent computations of delta_exec. That is, have write a theoretical timeline of events that shows in detail how this can mess things up. This makes understanding your changes much easier, otherwise you will have to wait till we have the time to look and figure things out ourselves. As we are currently working on other areas of the kernel so you will have to wait much longer than if you showed us exactly what happened. Thanks! -- Steve > > Signed-off-by: Hillf Danton > --- > kernel/sched_rt.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c > index 88725c9..0f0cfce 100644 > --- a/kernel/sched_rt.c > +++ b/kernel/sched_rt.c > @@ -1166,7 +1166,6 @@ static struct task_struct > *pick_next_task_rt(struct rq *rq) > static void put_prev_task_rt(struct rq *rq, struct task_struct *p) > { > update_curr_rt(rq); > - p->se.exec_start = 0; > > /* > * The previous task needs to be made eligible for pushing