From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755907Ab3F1ROr (ORCPT ); Fri, 28 Jun 2013 13:14:47 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:45171 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755346Ab3F1ROp (ORCPT ); Fri, 28 Jun 2013 13:14:45 -0400 Date: Fri, 28 Jun 2013 22:44:27 +0530 From: Srikar Dronamraju To: Mel Gorman Cc: Peter Zijlstra , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Linux-MM , LKML Subject: Re: [PATCH 5/8] sched: Favour moving tasks towards the preferred node Message-ID: <20130628171427.GO8362@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20130628090447.GD28407@twins.programming.kicks-ass.net> <20130628100723.GC8362@linux.vnet.ibm.com> <20130628135114.GY1875@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20130628135114.GY1875@suse.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13062817-7282-0000-0000-000018C435ED Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Yes, I understand that numa should have more priority over cache. > > But the schedstats will not be updated about whether the task was hot or > > cold. > > > > So lets say the task was cache hot but numa wants it to move, then we > > should certainly move it but we should update the schedstats to mention that we > > moved a cache hot task. > > > > Something akin to this. > > > > tsk_cache_hot = task_hot(p, env->src_rq->clock_task, env->sd); > > if (tsk_cache_hot) { > > if (migrate_improves_locality(p, env) || > > (env->sd->nr_balance_failed > env->sd->cache_nice_tries)) { > > #ifdef CONFIG_SCHEDSTATS > > schedstat_inc(env->sd, lb_hot_gained[env->idle]); > > schedstat_inc(p, se.statistics.nr_forced_migrations); > > #endif > > return 1; > > } > > schedstat_inc(p, se.statistics.nr_failed_migrations_hot); > > return 0; > > } > > return 1; > > > > Thanks. Is this acceptable? > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index b3848e0..c3a153e 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -4088,8 +4088,13 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env) > * 3) too many balance attempts have failed. > */ > > - if (migrate_improves_locality(p, env)) > + if (migrate_improves_locality(p, env)) { > +#ifdef CONFIG_SCHEDSTATS > + schedstat_inc(env->sd, lb_hot_gained[env->idle]); > + schedstat_inc(p, se.statistics.nr_forced_migrations); > +#endif > return 1; > + } > In this case, we account even cache cold threads as _cache hot_ in schedstats. We need the task_hot() call to determine if task is cache hot or not. So the migrate_improves_locality(), I think should be called within the tsk_cache_hot check. Do you have issues with the above snippet that I posted earlier? > tsk_cache_hot = task_hot(p, env->src_rq->clock_task, env->sd); > if (!tsk_cache_hot) > > -- > Mel Gorman > SUSE Labs > -- Thanks and Regards Srikar Dronamraju