From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758134AbZDIApd (ORCPT ); Wed, 8 Apr 2009 20:45:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755580AbZDIApY (ORCPT ); Wed, 8 Apr 2009 20:45:24 -0400 Received: from a-sasl-fastnet.sasl.smtp.pobox.com ([207.106.133.19]:44278 "EHLO sasl.smtp.pobox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753498AbZDIApX (ORCPT ); Wed, 8 Apr 2009 20:45:23 -0400 Date: Wed, 8 Apr 2009 19:45:12 -0500 From: Nathan Lynch To: linux-kernel@vger.kernel.org Cc: containers@lists.linux-foundation.org, linux-pm@lists.linux-foundation.org, Ingo Molnar , Andrew Morton , Matt Helsley Subject: [PATCH/RFC] do not count frozen tasks toward load Message-ID: <20090408194512.47a99b95@manatee.lan> X-Mailer: Claws Mail 3.7.0 (GTK+ 2.14.7; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Pobox-Relay-ID: B4906714-249F-11DE-9DFF-BB14ECB1AA3C-04752483!a-sasl-fastnet.pobox.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- include/linux/sched.h | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 011db2f..f8af167 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -202,7 +202,8 @@ extern unsigned long long time_sync_thresh; #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) -- 1.6.0.6