From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754110Ab1IPHlP (ORCPT ); Fri, 16 Sep 2011 03:41:15 -0400 Received: from smtp-out.google.com ([74.125.121.67]:42206 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753686Ab1IPHlO (ORCPT ); Fri, 16 Sep 2011 03:41:14 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=dkim-signature:message-id:date:from:user-agent: mime-version:newsgroups:to:cc:subject:references:in-reply-to: content-type:content-transfer-encoding:x-system-of-record; b=mq/i+q37lbRtU9G25aVK56jbMfr1vsXoLWVJ28GckUuQXqc1R11cF2/xCoD/wqVwS IimExRZ57rRf/Jza7L7QA== Message-ID: <4E72FD93.2060805@google.com> Date: Fri, 16 Sep 2011 00:41:07 -0700 From: Paul Turner User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.21) Gecko/20110831 Thunderbird/3.1.13 MIME-Version: 1.0 Newsgroups: gmane.linux.kernel To: Wang Xingchao CC: linux-kernel@vger.kernel.org, mingo@elte.hu, peterz@infradead.org, yong.zhang0@gmail.com Subject: Re: [PATCH] cfs: remove unused 'if' condition checking References: <1316194552-12019-1-git-send-email-xingchao.wang@intel.com> In-Reply-To: <1316194552-12019-1-git-send-email-xingchao.wang@intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/16/11 10:35, Wang Xingchao wrote: Please include a one-line summary such as: sched: remove extra nr_running check in check_preempt_tick > nr_running must be more than 1, so remove the checking > Sure, reasonable. Please expand this comment though, e.g. We already test for nr_running > 1 within entity_tick so there is no need to recheck it within check_preempt_tick(). > Signed-off-by: Wang Xingchao Reviewed-by: Paul Turner > --- > kernel/sched_fair.c | 16 ++++++++-------- > 1 files changed, 8 insertions(+), 8 deletions(-) > > diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c > index 1ca2cd4..fef0bfd 100644 > --- a/kernel/sched_fair.c > +++ b/kernel/sched_fair.c > @@ -1106,6 +1106,8 @@ static void > check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) > { > unsigned long ideal_runtime, delta_exec; > + struct sched_entity *se; > + s64 delta; > > ideal_runtime = sched_slice(cfs_rq, curr); > delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; > @@ -1127,16 +1129,14 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) > if (delta_exec< sysctl_sched_min_granularity) You've mangled the white space on the less-than. > return; > > - if (cfs_rq->nr_running> 1) { > - struct sched_entity *se = __pick_first_entity(cfs_rq); > - s64 delta = curr->vruntime - se->vruntime; > + se = __pick_first_entity(cfs_rq); > + delta = curr->vruntime - se->vruntime; > > - if (delta< 0) > - return; > + if (delta< 0) And here. > + return; > > - if (delta> ideal_runtime) > - resched_task(rq_of(cfs_rq)->curr); > - } > + if (delta> ideal_runtime) Here too. > + resched_task(rq_of(cfs_rq)->curr); > } > > static void