From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161335Ab2GLSo7 (ORCPT ); Thu, 12 Jul 2012 14:44:59 -0400 Received: from mailout-de.gmx.net ([213.165.64.22]:47265 "HELO mailout-de.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S932810Ab2GLSo4 (ORCPT ); Thu, 12 Jul 2012 14:44:56 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX19i8yRYCIViT6SRi6xO8EH8NQDeYr24MWz473ISSP ecUxEBbL3F03ws Message-ID: <1342118691.7430.39.camel@marge.simpson.net> Subject: Re: [PATCH] sched: remove useless code in yield_to From: Mike Galbraith To: Peter Zijlstra Cc: Michael Wang , LKML , Ingo Molnar Date: Thu, 12 Jul 2012 20:44:51 +0200 In-Reply-To: <1342102029.28010.3.camel@twins> References: <4F13EFBE.1030002@linux.vnet.ibm.com> <1326707503.2442.219.camel@twins> <4F14DEAE.60702@linux.vnet.ibm.com> <4F14E54E.80904@linux.vnet.ibm.com> <1327506934.2614.87.camel@laptop> <20120126100429.GA3853@elte.hu> <4F21FC69.6040402@linux.vnet.ibm.com> <4F222B2B.6010602@gmail.com> <4F24E804.5090808@linux.vnet.ibm.com> <20120129163328.GC23408@elte.hu> <4F260BFE.2070503@linux.vnet.ibm.com> <4F260DAE.4000008@gmail.com> <4F262ED9.7040003@linux.vnet.ibm.com> <4FF2925A.9060005@linux.vnet.ibm.com> <1342102029.28010.3.camel@twins> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2012-07-12 at 16:07 +0200, Peter Zijlstra wrote: > On Tue, 2012-07-03 at 14:34 +0800, Michael Wang wrote: > > From: Michael Wang > > > > it's impossible to enter else branch if we have set skip_clock_update > > in task_yield_fair(), as yield_to_task_fair() will directly return > > true after invoke task_yield_fair(). > > It helps if you CC the guy who wrote the code.. I think you're right, > although getting that skip_clock_update crap wrong is annoying. Getting that crap wrong is ease, so Michael is probably right. > Mike? If it looks right to you too, it likely is. When I have time to look for nanoseconds again, I can squeak if/when I find some. In any case, for normal scheduler citizens, it's chump change, so nuke it. > > Signed-off-by: Michael Wang > > --- > > kernel/sched/core.c | 7 ------- > > 1 files changed, 0 insertions(+), 7 deletions(-) > > > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > > index 9bb7d28..77c14aa 100644 > > --- a/kernel/sched/core.c > > +++ b/kernel/sched/core.c > > @@ -4737,13 +4737,6 @@ again: > > */ > > if (preempt && rq != p_rq) > > resched_task(p_rq->curr); > > - } else { > > - /* > > - * We might have set it in task_yield_fair(), but are > > - * not going to schedule(), so don't want to skip > > - * the next update. > > - */ > > - rq->skip_clock_update = 0; > > } > > > > out: > > -- > 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/