Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753016Ab3CTGwB (ORCPT ); Wed, 20 Mar 2013 02:52:01 -0400 Received: from LGEMRELSE1Q.lge.com ([156.147.1.111]:57123 "EHLO LGEMRELSE1Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750982Ab3CTGv7 (ORCPT ); Wed, 20 Mar 2013 02:51:59 -0400 X-AuditID: 9c93016f-b7cecae000004cf8-15-51495c89323c Date: Wed, 20 Mar 2013 15:52:18 +0900 From: Joonsoo Kim To: Peter Zijlstra Cc: Ingo Molnar , Srivatsa Vaddagiri , linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/8] sched: don't consider other cpus in our group in case of NEWLY_IDLE Message-ID: <20130320065218.GB11672@lge.com> References: <1360820921-2513-1-git-send-email-iamjoonsoo.kim@lge.com> <1360820921-2513-4-git-send-email-iamjoonsoo.kim@lge.com> <1363702857.22553.50.camel@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1363702857.22553.50.camel@laptop> User-Agent: Mutt/1.5.21 (2010-09-15) X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2369 Lines: 62 On Tue, Mar 19, 2013 at 03:20:57PM +0100, Peter Zijlstra wrote: > On Thu, 2013-02-14 at 14:48 +0900, Joonsoo Kim wrote: > > Commit 88b8dac0 makes load_balance() consider other cpus in its group, > > regardless of idle type. When we do NEWLY_IDLE balancing, we should not > > consider it, because a motivation of NEWLY_IDLE balancing is to turn > > this cpu to non idle state if needed. This is not the case of other cpus. > > So, change code not to consider other cpus for NEWLY_IDLE balancing. > > > > With this patch, assign 'if (pulled_task) this_rq->idle_stamp = 0' > > in idle_balance() is corrected, because NEWLY_IDLE balancing doesn't > > consider other cpus. Assigning to 'this_rq->idle_stamp' is now valid. > > > > Cc: Srivatsa Vaddagiri > > Signed-off-by: Joonsoo Kim > > Fair enough, good catch. > > Acked-by: Peter Zijlstra > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index 0c6aaf6..97498f4 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -5016,8 +5016,15 @@ static int load_balance(int this_cpu, struct rq *this_rq, > > .cpus = cpus, > > }; > > > > + /* For NEWLY_IDLE load_balancing, we don't need to consider > > + * other cpus in our group */ > > + if (idle == CPU_NEWLY_IDLE) { > > + env.dst_grpmask = NULL; > > + max_lb_iterations = 0; > > Just a small nit; I don't think we'll ever get to evaluate > max_lb_iterations when !dst_grpmask. So strictly speaking its > superfluous to touch it. Okay. In next spin, I will remove it and add a comment here. Thanks. > > > + } else { > > + max_lb_iterations = cpumask_weight(env.dst_grpmask); > > + } > > cpumask_copy(cpus, cpu_active_mask); > > - max_lb_iterations = cpumask_weight(env.dst_grpmask); > > > > schedstat_inc(sd, lb_count[idle]); > > > > > -- > 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/ -- 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/