Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753219AbbDGUYc (ORCPT ); Tue, 7 Apr 2015 16:24:32 -0400 Received: from g9t5009.houston.hp.com ([15.240.92.67]:41313 "EHLO g9t5009.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752883AbbDGUY2 (ORCPT ); Tue, 7 Apr 2015 16:24:28 -0400 Message-ID: <1428438263.2556.74.camel@j-VirtualBox> Subject: Re: sched: Improve load balancing in the presence of idle CPUs From: Jason Low To: Tim Chen Cc: Morten Rasmussen , Preeti U Murthy , "peterz@infradead.org" , "mingo@kernel.org" , Daniel Lezcano , "riel@redhat.com" , "vincent.guittot@linaro.org" , "srikar@linux.vnet.ibm.com" , "pjt@google.com" , "benh@kernel.crashing.org" , "efault@gmx.de" , "linux-kernel@vger.kernel.org" , "iamjoonsoo.kim@lge.com" , "svaidy@linux.vnet.ibm.com" , jason.low2@hp.com Date: Tue, 07 Apr 2015 13:24:23 -0700 In-Reply-To: <1428435564.660.39.camel@schen9-desk2.jf.intel.com> References: <1427741729.5694.24.camel@j-VirtualBox> <551A5CCE.70008@linux.vnet.ibm.com> <1427828056.2492.24.camel@j-VirtualBox> <551B9514.80701@linux.vnet.ibm.com> <20150401170418.GX18994@e105550-lin.cambridge.arm.com> <1427954347.2556.43.camel@j-VirtualBox> <1428100518.660.34.camel@schen9-desk2.jf.intel.com> <1428428561.2556.63.camel@j-VirtualBox> <1428435564.660.39.camel@schen9-desk2.jf.intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1682 Lines: 50 On Tue, 2015-04-07 at 12:39 -0700, Tim Chen wrote: > How about consolidating the code for passing the > nohz balancing and call it at both places. > Something like below. Make the code more readable. > > Tim > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 40667cb..16f6904 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -7531,6 +7531,15 @@ out: > } > > #ifdef CONFIG_NO_HZ_COMMON > +static inline int nohz_kick_needed(struct rq *rq); > + > +static void inline pass_nohz_balance(struct rq *this_rq, int this_cpu) > +{ > + clear_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu)); > + if (nohz_kick_needed(this_rq)) > + nohz_balancer_kick(); > +} > + > /* > * In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the > * rebalancing for all the cpus for whom scheduler ticks are stopped. > @@ -7542,8 +7551,10 @@ static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) > int balance_cpu; > > if (idle != CPU_IDLE || > - !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu))) > - goto end; > + !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu))) { > + pass_nohz_balance(this_rq, this_cpu); > + return; > + } Sure, this can make it more readable. This also avoids the need for the goto, in addition to removing the done_balancing boolean. Thanks, Jason -- 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/