From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753545AbcEZJL7 (ORCPT ); Thu, 26 May 2016 05:11:59 -0400 Received: from mga04.intel.com ([192.55.52.120]:44243 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753386AbcEZJL6 (ORCPT ); Thu, 26 May 2016 05:11:58 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,367,1459839600"; d="scan'208";a="985059908" From: Yuyang Du To: peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org Cc: bsegall@google.com, pjt@google.com, morten.rasmussen@arm.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, byungchul.park@lge.com, Yuyang Du Subject: [PATCH 1/2] sched/fair: Clean up attach_entity_load_avg() Date: Thu, 26 May 2016 09:14:23 +0800 Message-Id: <1464225264-32760-2-git-send-email-yuyang.du@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1464225264-32760-1-git-send-email-yuyang.du@intel.com> References: <1464225264-32760-1-git-send-email-yuyang.du@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org attach_entity_load_avg() is called (indirectly) from: - switched_to_fair(): switch between classes to fair - task_move_group_fair(): move between task groups - enqueue_entity_load_avg(): enqueue entity Only in switched_to_fair() is it possible that the task's last_update_time is not 0 and therefore the task needs sched avgs update, so move the task sched avgs update to switched_to_fair() only. In addition, code comments are clarified. No functionality change. Signed-off-by: Yuyang Du --- kernel/sched/fair.c | 39 +++++++++++++++++++++------------------ 1 file changed, 21 insertions(+), 18 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 218f8e8..e89c39b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2961,24 +2961,6 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg) static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { - if (!sched_feat(ATTACH_AGE_LOAD)) - goto skip_aging; - - /* - * If we got migrated (either between CPUs or between cgroups) we'll - * have aged the average right before clearing @last_update_time. - */ - if (se->avg.last_update_time) { - __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)), - &se->avg, 0, 0, NULL); - - /* - * XXX: we could have just aged the entire load away if we've been - * absent from the fair class for too long. - */ - } - -skip_aging: se->avg.last_update_time = cfs_rq->avg.last_update_time; cfs_rq->avg.load_avg += se->avg.load_avg; cfs_rq->avg.load_sum += se->avg.load_sum; @@ -8418,6 +8400,27 @@ static void switched_from_fair(struct rq *rq, struct task_struct *p) static void switched_to_fair(struct rq *rq, struct task_struct *p) { +#ifdef CONFIG_SMP + struct sched_entity *se = &p->se; + + if (!sched_feat(ATTACH_AGE_LOAD)) + goto skip_aging; + + /* + * If we change between classes, age the averages before attaching them. + */ + if (se->avg.last_update_time) { + __update_load_avg(cfs_rq_of(se)->avg.last_update_time, cpu_of(rq), + &se->avg, 0, 0, NULL); + + /* + * XXX: we could have just aged the entire load away if we've been + * absent from the fair class for too long. + */ + } + +skip_aging: +#endif attach_task_cfs_rq(p); if (task_on_rq_queued(p)) { -- 1.7.9.5