From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760061AbZD2WcS (ORCPT ); Wed, 29 Apr 2009 18:32:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759444AbZD2WVf (ORCPT ); Wed, 29 Apr 2009 18:21:35 -0400 Received: from kroah.org ([198.145.64.141]:40500 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759265AbZD2WVb (ORCPT ); Wed, 29 Apr 2009 18:21:31 -0400 X-Mailbox-Line: From gregkh@mini.kroah.org Wed Apr 29 15:09:27 2009 Message-Id: <20090429220927.416887820@mini.kroah.org> User-Agent: quilt/0.48-1 Date: Wed, 29 Apr 2009 15:07:28 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , Willy Tarreau , Rodrigo Rubira Branco , Jake Edge , Eugene Teo , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Nathan Lynch , Nigel Cunningham , containers@lists.linux-foundation.org, linux-pm@lists.linux-foundation.org, Matt Helsley , Ingo Molnar , Chris Wright Subject: [patch 29/58] sched: do not count frozen tasks toward load References: <20090429220659.339950874@mini.kroah.org> Content-Disposition: inline; filename=0060-sched-do-not-count-frozen-tasks-toward-load.patch In-Reply-To: <20090429221657.GA11765@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------ From: Nathan Lynch upstream commit: e3c8ca8336707062f3f7cb1cd7e6b3c753baccdd Freezing tasks via the cgroup freezer causes the load average to climb because the freezer's current implementation puts frozen tasks in uninterruptible sleep (D state). Some applications which perform job-scheduling functions consult the load average when making decisions. If a cgroup is frozen, the load average does not provide a useful measure of the system's utilization to such applications. This is especially inconvenient if the job scheduler employs the cgroup freezer as a mechanism for preempting low priority jobs. Contrast this with using SIGSTOP for the same purpose: the stopped tasks do not count toward system load. Change task_contributes_to_load() to return false if the task is frozen. This results in /proc/loadavg behavior that better meets users' expectations. Signed-off-by: Nathan Lynch Acked-by: Andrew Morton Acked-by: Nigel Cunningham Tested-by: Nigel Cunningham Cc: containers@lists.linux-foundation.org Cc: linux-pm@lists.linux-foundation.org Cc: Matt Helsley LKML-Reference: <20090408194512.47a99b95@manatee.lan> Signed-off-by: Ingo Molnar Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman --- include/linux/sched.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -201,7 +201,8 @@ extern unsigned long long time_sync_thre #define task_is_stopped_or_traced(task) \ ((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0) #define task_contributes_to_load(task) \ - ((task->state & TASK_UNINTERRUPTIBLE) != 0) + ((task->state & TASK_UNINTERRUPTIBLE) != 0 && \ + (task->flags & PF_FROZEN) == 0) #define __set_task_state(tsk, state_value) \ do { (tsk)->state = (state_value); } while (0)