From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57646 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752046AbcJDPS7 (ORCPT ); Tue, 4 Oct 2016 11:18:59 -0400 Subject: Patch "sched/cputime: Fix prev steal time accouting during CPU hotplug" has been added to the 4.7-stable tree To: wanpeng.li@hotmail.com, efault@gmx.de, fweisbec@gmail.com, gregkh@linuxfoundation.org, mingo@kernel.org, pbonzini@redhat.com, peterz@infradead.org, riel@redhat.com, rkrcmar@redhat.com, tglx@linutronix.de, torvalds@linux-foundation.org Cc: , From: Date: Tue, 04 Oct 2016 17:18:12 +0200 Message-ID: <147559429267152@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled sched/cputime: Fix prev steal time accouting during CPU hotplug to the 4.7-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sched-cputime-fix-prev-steal-time-accouting-during-cpu-hotplug.patch and it can be found in the queue-4.7 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 3d89e5478bf550a50c99e93adf659369798263b0 Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Mon, 13 Jun 2016 18:32:45 +0800 Subject: sched/cputime: Fix prev steal time accouting during CPU hotplug MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Wanpeng Li commit 3d89e5478bf550a50c99e93adf659369798263b0 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- kernel/sched/core.c | 1 - kernel/sched/sched.h | 13 ------------- 2 files changed, 14 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7255,7 +7255,6 @@ static void sched_rq_cpu_starting(unsign struct rq *rq = cpu_rq(cpu); rq->calc_load_update = calc_load_update; - account_reset_rq(rq); update_max_interval(); } --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1809,16 +1809,3 @@ static inline void cpufreq_trigger_updat #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 -} Patches currently in stable-queue which might be from wanpeng.li@hotmail.com are queue-4.7/sched-cputime-fix-prev-steal-time-accouting-during-cpu-hotplug.patch