From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934683AbeBML3J (ORCPT ); Tue, 13 Feb 2018 06:29:09 -0500 Received: from terminus.zytor.com ([198.137.202.136]:54629 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934532AbeBML3G (ORCPT ); Tue, 13 Feb 2018 06:29:06 -0500 Date: Tue, 13 Feb 2018 03:28:45 -0800 From: tip-bot for Wen Yang Message-ID: Cc: jiang.biao2@zte.com.cn, hpa@zytor.com, wen.yang99@zte.com.cn, tglx@linutronix.de, torvalds@linux-foundation.org, peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org Reply-To: hpa@zytor.com, jiang.biao2@zte.com.cn, torvalds@linux-foundation.org, tglx@linutronix.de, wen.yang99@zte.com.cn, linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@kernel.org In-Reply-To: <1517882008-44552-1-git-send-email-wen.yang99@zte.com.cn> References: <1517882008-44552-1-git-send-email-wen.yang99@zte.com.cn> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] sched/rt: Make update_curr_rt() more accurate Git-Commit-ID: a7711602c7b79950ea437178f601b52ab08ef659 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: a7711602c7b79950ea437178f601b52ab08ef659 Gitweb: https://git.kernel.org/tip/a7711602c7b79950ea437178f601b52ab08ef659 Author: Wen Yang AuthorDate: Tue, 6 Feb 2018 09:53:28 +0800 Committer: Ingo Molnar CommitDate: Tue, 13 Feb 2018 11:44:41 +0100 sched/rt: Make update_curr_rt() more accurate 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 Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Jiang Biao Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: zhong.weidong@zte.com.cn Link: http://lkml.kernel.org/r/1517882008-44552-1-git-send-email-wen.yang99@zte.com.cn Signed-off-by: Ingo Molnar --- kernel/sched/rt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 663b235..aad49451 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -950,12 +950,13 @@ static void update_curr_rt(struct rq *rq) { struct task_struct *curr = rq->curr; struct sched_rt_entity *rt_se = &curr->rt; - u64 now = rq_clock_task(rq); u64 delta_exec; + u64 now; if (curr->sched_class != &rt_sched_class) return; + now = rq_clock_task(rq); delta_exec = now - curr->se.exec_start; if (unlikely((s64)delta_exec <= 0)) return;