From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751981AbcEJSTy (ORCPT ); Tue, 10 May 2016 14:19:54 -0400 Received: from mail-pf0-f172.google.com ([209.85.192.172]:34557 "EHLO mail-pf0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751325AbcEJSTx (ORCPT ); Tue, 10 May 2016 14:19:53 -0400 From: bsegall@google.com To: Xunlei Pang Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Juri Lelli , Ingo Molnar , Steven Rostedt , pjt@google.com Subject: Re: [PATCH] sched/fair: Fix the wrong throttled clock time for cfs_rq_clock_task() References: <1462885398-14724-1-git-send-email-xlpang@redhat.com> Date: Tue, 10 May 2016 11:19:44 -0700 In-Reply-To: <1462885398-14724-1-git-send-email-xlpang@redhat.com> (Xunlei Pang's message of "Tue, 10 May 2016 21:03:18 +0800") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Xunlei Pang writes: > Two minor fixes for cfs_rq_clock_task(). > 1) If cfs_rq is currently being throttled, we need to subtract the cfs > throttled clock time. > > 2) Make "throttled_clock_task_time" update SMP unrelated. Now UP cases > need it as well. > > Signed-off-by: Xunlei Pang > --- > kernel/sched/fair.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 1708729e..fb80a12 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -3655,7 +3655,7 @@ static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) > static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq) > { > if (unlikely(cfs_rq->throttle_count)) > - return cfs_rq->throttled_clock_task; > + return cfs_rq->throttled_clock_task - cfs_rq->throttled_clock_task_time; > > return rq_clock_task(rq_of(cfs_rq)) - cfs_rq->throttled_clock_task_time; > } > @@ -3793,13 +3793,11 @@ static int tg_unthrottle_up(struct task_group *tg, void *data) > struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; > > cfs_rq->throttle_count--; > -#ifdef CONFIG_SMP > if (!cfs_rq->throttle_count) { > /* adjust cfs_rq_clock_task() */ > cfs_rq->throttled_clock_task_time += rq_clock_task(rq) - > cfs_rq->throttled_clock_task; > } > -#endif > > return 0; > } [Cc: pjt@google.com] This looks reasonable to me (at least the first part; I'm not certain why the CONFIG_SMP ifdef was put in place).