From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:48309 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933514AbcIENha (ORCPT ); Mon, 5 Sep 2016 09:37:30 -0400 Subject: Patch "sched/nohz: Fix affine unpinned timers mess" has been added to the 4.4-stable tree To: wanpeng.li@hotmail.com, efault@gmx.de, fweisbec@gmail.com, gregkh@linuxfoundation.org, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org Cc: , From: Date: Mon, 05 Sep 2016 15:37:04 +0200 Message-ID: <1473082624247177@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 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/nohz: Fix affine unpinned timers mess to the 4.4-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-nohz-fix-affine-unpinned-timers-mess.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 444969223c81c7d0a95136b7b4cfdcfbc96ac5bd Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Wed, 4 May 2016 14:45:34 +0800 Subject: sched/nohz: Fix affine unpinned timers mess From: Wanpeng Li commit 444969223c81c7d0a95136b7b4cfdcfbc96ac5bd upstream. The following commit: 9642d18eee2c ("nohz: Affine unpinned timers to housekeepers")' intended to affine unpinned timers to housekeepers: unpinned timers(full dynaticks, idle) => nearest busy housekeepers(otherwise, fallback to any housekeepers) unpinned timers(full dynaticks, busy) => nearest busy housekeepers(otherwise, fallback to any housekeepers) unpinned timers(houserkeepers, idle) => nearest busy housekeepers(otherwise, fallback to itself) However, the !idle_cpu(i) && is_housekeeping_cpu(cpu) check modified the intention to: unpinned timers(full dynaticks, idle) => any housekeepers(no mattter cpu topology) unpinned timers(full dynaticks, busy) => any housekeepers(no mattter cpu topology) unpinned timers(housekeepers, idle) => any busy cpus(otherwise, fallback to any housekeepers) This patch fixes it by checking if there are busy housekeepers nearby, otherwise falls to any housekeepers/itself. After the patch: unpinned timers(full dynaticks, idle) => nearest busy housekeepers(otherwise, fallback to any housekeepers) unpinned timers(full dynaticks, busy) => nearest busy housekeepers(otherwise, fallback to any housekeepers) unpinned timers(housekeepers, idle) => nearest busy housekeepers(otherwise, fallback to itself) Signed-off-by: Wanpeng Li Signed-off-by: Peter Zijlstra (Intel) [ Fixed the changelog. ] Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Fixes: 'commit 9642d18eee2c ("nohz: Affine unpinned timers to housekeepers")' Link: http://lkml.kernel.org/r/1462344334-8303-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/sched/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -627,7 +627,10 @@ int get_nohz_timer_target(void) rcu_read_lock(); for_each_domain(cpu, sd) { for_each_cpu(i, sched_domain_span(sd)) { - if (!idle_cpu(i) && is_housekeeping_cpu(cpu)) { + if (cpu == i) + continue; + + if (!idle_cpu(i) && is_housekeeping_cpu(i)) { cpu = i; goto unlock; } Patches currently in stable-queue which might be from wanpeng.li@hotmail.com are queue-4.4/sched-nohz-fix-affine-unpinned-timers-mess.patch queue-4.4/sched-cputime-fix-no_hz_full-getrusage-monotonicity-regression.patch