From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:58476 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932458AbcLLWrQ (ORCPT ); Mon, 12 Dec 2016 17:47:16 -0500 Subject: Patch "sched/autogroup: Fix 64-bit kernel nice level adjustment" has been added to the 4.8-stable tree To: efault@gmx.de, a.p.zijlstra@chello.nl, gregkh@linuxfoundation.org, linux-man@vger.kernel.org, mingo@kernel.org, mtk.manpages@gmail.com, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org, umgwanakikbuti@gmail.com Cc: , From: Date: Mon, 12 Dec 2016 14:47:24 -0800 Message-ID: <148158284417581@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/autogroup: Fix 64-bit kernel nice level adjustment to the 4.8-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-autogroup-fix-64-bit-kernel-nice-level-adjustment.patch and it can be found in the queue-4.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 83929cce95251cc77e5659bf493bd424ae0e7a67 Mon Sep 17 00:00:00 2001 From: Mike Galbraith Date: Wed, 23 Nov 2016 11:33:37 +0100 Subject: sched/autogroup: Fix 64-bit kernel nice level adjustment From: Mike Galbraith commit 83929cce95251cc77e5659bf493bd424ae0e7a67 upstream. Michael Kerrisk reported: > Regarding the previous paragraph... My tests indicate > that writing *any* value to the autogroup [nice priority level] > file causes the task group to get a lower priority. Because autogroup didn't call the then meaningless scale_load()... Autogroup nice level adjustment has been broken ever since load resolution was increased for 64-bit kernels. Use scale_load() to scale group weight. Michael Kerrisk tested this patch to fix the problem: > Applied and tested against 4.9-rc6 on an Intel u7 (4 cores). > Test setup: > > Terminal window 1: running 40 CPU burner jobs > Terminal window 2: running 40 CPU burner jobs > Terminal window 1: running 1 CPU burner job > > Demonstrated that: > * Writing "0" to the autogroup file for TW1 now causes no change > to the rate at which the process on the terminal consume CPU. > * Writing -20 to the autogroup file for TW1 caused those processes > to get the lion's share of CPU while TW2 TW3 get a tiny amount. > * Writing -20 to the autogroup files for TW1 and TW3 allowed the > process on TW3 to get as much CPU as it was getting as when > the autogroup nice values for both terminals were 0. Reported-by: Michael Kerrisk Tested-by: Michael Kerrisk Signed-off-by: Mike Galbraith Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-man Link: http://lkml.kernel.org/r/1479897217.4306.6.camel@gmx.de Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/sched/auto_group.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/kernel/sched/auto_group.c +++ b/kernel/sched/auto_group.c @@ -192,6 +192,7 @@ int proc_sched_autogroup_set_nice(struct { static unsigned long next = INITIAL_JIFFIES; struct autogroup *ag; + unsigned long shares; int err; if (nice < MIN_NICE || nice > MAX_NICE) @@ -210,9 +211,10 @@ int proc_sched_autogroup_set_nice(struct next = HZ / 10 + jiffies; ag = autogroup_task_get(p); + shares = scale_load(sched_prio_to_weight[nice + 20]); down_write(&ag->lock); - err = sched_group_set_shares(ag->tg, sched_prio_to_weight[nice + 20]); + err = sched_group_set_shares(ag->tg, shares); if (!err) ag->nice = nice; up_write(&ag->lock); Patches currently in stable-queue which might be from efault@gmx.de are queue-4.8/sched-autogroup-fix-64-bit-kernel-nice-level-adjustment.patch