From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28F5BC54FC9 for ; Tue, 21 Apr 2020 10:50:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 09C652084D for ; Tue, 21 Apr 2020 10:50:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728602AbgDUKuS (ORCPT ); Tue, 21 Apr 2020 06:50:18 -0400 Received: from mga07.intel.com ([134.134.136.100]:22658 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726741AbgDUKuR (ORCPT ); Tue, 21 Apr 2020 06:50:17 -0400 IronPort-SDR: Xmb6aiz7XMAis+pfDYhD1qcJwwlz1UKwY3pOH/ewBfmV6AWGVE3ZEhW4lJLgTvEqgPVFXJgl4X W5mdD/ptvGHw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Apr 2020 03:50:17 -0700 IronPort-SDR: 1/7uHZJs+ksuoPYOpbP3jEsnt+fB9q2u4GE7YI0HccD9ma8xvDqB98w96Lefg3XXDrj5rXutF8 w+FVaCZlqTSA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,410,1580803200"; d="scan'208";a="247146052" Received: from chenyu-office.sh.intel.com ([10.239.158.173]) by fmsmga008.fm.intel.com with ESMTP; 21 Apr 2020 03:50:14 -0700 From: Chen Yu To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Vincent Guittot , Steven Rostedt , Valentin Schneider , Ingo Molnar , Juri Lelli , Dietmar Eggemann , Mel Gorman , Ben Segall , Chen Yu Subject: [PATCH 2/2][v3] sched: Extract the task putting code from pick_next_task() Date: Tue, 21 Apr 2020 18:50:43 +0800 Message-Id: <5a99860cf66293db58a397d6248bcb2eee326776.1587464698.git.yu.c.chen@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Introduce a new function put_prev_task_balance() to do the balance when necessary, and then put previous task back to the run queue. This function is extracted from pick_next_task() to prepare for future usage by other type of task picking logic. No functional change. Suggested-by: Peter Zijlstra Reviewed-by: Valentin Schneider Signed-off-by: Chen Yu --- v3: According to Steven's suggestion, fix the comment to change put_next_task() to put_prev_task() Rename finish_prev_task() to put_prev_task_balance() as this reflects what we do before picking a new task. Per Valentin's suggestion, put the declaration of struct sched_class within the ifdef, given it isn't used outside of it. --- kernel/sched/core.c | 39 +++++++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 16 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3a61a3b8eaa9..c9d7880f6bf2 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3904,6 +3904,28 @@ static inline void schedule_debug(struct task_struct *prev, bool preempt) schedstat_inc(this_rq()->sched_count); } +static void put_prev_task_balance(struct rq *rq, struct task_struct *prev, + struct rq_flags *rf) +{ +#ifdef CONFIG_SMP + const struct sched_class *class; + /* + * We must do the balancing pass before put_prev_task(), such + * that when we release the rq->lock the task is in the same + * state as before we took rq->lock. + * + * We can terminate the balance pass as soon as we know there is + * a runnable task of @class priority or higher. + */ + for_class_range(class, prev->sched_class, &idle_sched_class) { + if (class->balance(rq, prev, rf)) + break; + } +#endif + + put_prev_task(rq, prev); +} + /* * Pick up the highest-prio task: */ @@ -3937,22 +3959,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) } restart: -#ifdef CONFIG_SMP - /* - * We must do the balancing pass before put_next_task(), such - * that when we release the rq->lock the task is in the same - * state as before we took rq->lock. - * - * We can terminate the balance pass as soon as we know there is - * a runnable task of @class priority or higher. - */ - for_class_range(class, prev->sched_class, &idle_sched_class) { - if (class->balance(rq, prev, rf)) - break; - } -#endif - - put_prev_task(rq, prev); + put_prev_task_balance(rq, prev, rf); for_each_class(class) { p = class->pick_next_task(rq); -- 2.17.1