From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752103AbeBFB4J (ORCPT ); Mon, 5 Feb 2018 20:56:09 -0500 Received: from out1.zte.com.cn ([202.103.147.172]:54096 "EHLO mxct.zte.com.cn" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752069AbeBFB4B (ORCPT ); Mon, 5 Feb 2018 20:56:01 -0500 From: Wen Yang To: mingo@redhat.com, peterz@infradead.org Cc: linux-kernel@vger.kernel.org, jiang.biao2@zte.com.cn, zhong.weidong@zte.com.cn, wen.yang99@zte.com.cn Subject: [PATCH v2] sched/rt: Make update_curr_rt() more accurate Date: Tue, 6 Feb 2018 09:53:28 +0800 Message-Id: <1517882008-44552-1-git-send-email-wen.yang99@zte.com.cn> X-Mailer: git-send-email 1.8.3.1 X-MIMETrack: Itemize by SMTP Server on SZSMTP06/server/zte_ltd(Release 8.5.3FP6|November 21, 2013) at 2018-02-06 09:55:56, Serialize by Router on notes_smtp/zte_ltd(Release 9.0.1FP7|August 17, 2016) at 2018-02-06 09:55:49, Serialize complete at 2018-02-06 09:55:49 X-MAIL: mse01.zte.com.cn w161trV6038871 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org rq->clock_task may be updated between the two calls of rq_clock_task() in update_curr_rt(). Calling rq_clock_task() only once makes it more accurate and efficient, taking update_curr() as reference. Signed-off-by: Wen Yang Reviewed-by: Jiang Biao --- kernel/sched/rt.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 665ace2..fc527b1 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -951,11 +951,13 @@ static void update_curr_rt(struct rq *rq) struct task_struct *curr = rq->curr; struct sched_rt_entity *rt_se = &curr->rt; u64 delta_exec; + u64 now; if (curr->sched_class != &rt_sched_class) return; - delta_exec = rq_clock_task(rq) - curr->se.exec_start; + now = rq_clock_task(rq); + delta_exec = now - curr->se.exec_start; if (unlikely((s64)delta_exec <= 0)) return; @@ -968,7 +970,7 @@ static void update_curr_rt(struct rq *rq) curr->se.sum_exec_runtime += delta_exec; account_group_exec_runtime(curr, delta_exec); - curr->se.exec_start = rq_clock_task(rq); + curr->se.exec_start = now; cgroup_account_cputime(curr, delta_exec); sched_rt_avg_update(rq, delta_exec); -- 1.8.3.1