From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752056AbcFNL1R (ORCPT ); Tue, 14 Jun 2016 07:27:17 -0400 Received: from terminus.zytor.com ([198.137.202.10]:33982 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751140AbcFNL1P (ORCPT ); Tue, 14 Jun 2016 07:27:15 -0400 Date: Tue, 14 Jun 2016 04:26:40 -0700 From: tip-bot for Wanpeng Li Message-ID: Cc: fweisbec@gmail.com, peterz@infradead.org, riel@redhat.com, linux-kernel@vger.kernel.org, pbonzini@redhat.com, torvalds@linux-foundation.org, hpa@zytor.com, tglx@linutronix.de, mingo@kernel.org, wanpeng.li@hotmail.com, rkrcmar@redhat.com, efault@gmx.de Reply-To: pbonzini@redhat.com, mingo@kernel.org, torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com, wanpeng.li@hotmail.com, rkrcmar@redhat.com, efault@gmx.de, fweisbec@gmail.com, peterz@infradead.org, riel@redhat.com, linux-kernel@vger.kernel.org In-Reply-To: <1465813966-3116-3-git-send-email-wanpeng.li@hotmail.com> References: <1465813966-3116-3-git-send-email-wanpeng.li@hotmail.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/cputime: Fix prev steal time accouting during CPU hotplug Git-Commit-ID: 3d89e5478bf550a50c99e93adf659369798263b0 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: 3d89e5478bf550a50c99e93adf659369798263b0 Gitweb: http://git.kernel.org/tip/3d89e5478bf550a50c99e93adf659369798263b0 Author: Wanpeng Li AuthorDate: Mon, 13 Jun 2016 18:32:45 +0800 Committer: Ingo Molnar CommitDate: Tue, 14 Jun 2016 11:13:15 +0200 sched/cputime: Fix prev steal time accouting during CPU hotplug Commit: e9532e69b8d1 ("sched/cputime: Fix steal time accounting vs. CPU hotplug") ... set rq->prev_* to 0 after a CPU hotplug comes back, in order to fix the case where (after CPU hotplug) steal time is smaller than rq->prev_steal_time. However, this should never happen. Steal time was only smaller because of the KVM-specific bug fixed by the previous patch. Worse, the previous patch triggers a bug on CPU hot-unplug/plug operation: because rq->prev_steal_time is cleared, all of the CPU's past steal time will be accounted again on hot-plug. Since the root cause has been fixed, we can just revert commit e9532e69b8d1. Signed-off-by: Wanpeng Li Signed-off-by: Peter Zijlstra (Intel) Acked-by: Paolo Bonzini Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Radim Krčmář Cc: Rik van Riel Cc: Thomas Gleixner Fixes: 'commit e9532e69b8d1 ("sched/cputime: Fix steal time accounting vs. CPU hotplug")' Link: http://lkml.kernel.org/r/1465813966-3116-3-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 1 - kernel/sched/sched.h | 13 ------------- 2 files changed, 14 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 13d0896..c1b537b 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7227,7 +7227,6 @@ static void sched_rq_cpu_starting(unsigned int cpu) struct rq *rq = cpu_rq(cpu); rq->calc_load_update = calc_load_update; - account_reset_rq(rq); update_max_interval(); } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 72f1f30..de607e4 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1809,16 +1809,3 @@ static inline void cpufreq_trigger_update(u64 time) {} #else /* arch_scale_freq_capacity */ #define arch_scale_freq_invariant() (false) #endif - -static inline void account_reset_rq(struct rq *rq) -{ -#ifdef CONFIG_IRQ_TIME_ACCOUNTING - rq->prev_irq_time = 0; -#endif -#ifdef CONFIG_PARAVIRT - rq->prev_steal_time = 0; -#endif -#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING - rq->prev_steal_time_rq = 0; -#endif -}