From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755022Ab1BYLqV (ORCPT ); Fri, 25 Feb 2011 06:46:21 -0500 Received: from mail.in-telegence.net ([83.125.45.125]:56968 "EHLO amg.in-telegence.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751928Ab1BYLqU (ORCPT ); Fri, 25 Feb 2011 06:46:20 -0500 X-CTCH-RefID: str=0001.0A0B020B.4D679688.02E0,ss=1,fgs=0 Message-ID: <4D679688.7020503@in-telegence.net> Date: Fri, 25 Feb 2011 12:46:16 +0100 From: Dominik Klein User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.2.13) Gecko/20101207 Lightning/1.0b2 Thunderbird/3.1.7 MIME-Version: 1.0 To: Tejun Heo CC: Vivek Goyal , linux kernel mailing list , libvir-list@redhat.com Subject: Re: Is it a workqueue related issue in 2.6.37 (Was: Re: [libvirt] blkio cgroup [solved]) References: <4D63BA3B.7070809@in-telegence.net> <20110222152426.GD28269@redhat.com> <20110222190953.GF28269@redhat.com> <4D650D7E.4050908@in-telegence.net> <4D662248.6040405@in-telegence.net> <20110224142303.GA18494@redhat.com> <20110224143105.GL7840@htj.dyndns.org> <4D66720E.70102@in-telegence.net> <20110224151701.GQ7840@htj.dyndns.org> <4D67591F.10105@in-telegence.net> <20110225112936.GH24828@htj.dyndns.org> In-Reply-To: <20110225112936.GH24828@htj.dyndns.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi >> This was taken with 2.6.37 plus the patch you mentioned on a Dell R815 >> with 2 12 core AMD Opteron 6174 CPUs. If you need any more information, >> please let me know. > > Hmmm... well, I have no idea what you were trying to do Long story short: I have a couple of virtual machines. Some of them have blkio throttle configured, some don't. To simulate whether the throttling works, I start dd if=/dev/zero of=testfile bs=1M count=1500 in each guest simultaneously. The result is that from that point, no i/o is happening any more. You see the result in the trace. With 2.6.37 (also tried .1 and .2) it does not work but end up like I documented. With 2.6.38-rc1, it does work. With deadline scheduler, it also works in 2.6.37. I am in bisect run 2 currently to find the changeset that fixed it. Will let you know as soon as I do. Regards Dominik ps. I am by no means a kernel hacker and none of the rest of your email made any sense to me. Sorry. > but here are > some info which might be helpful. > > * queue_work happens when the work item is queued. > > * activate_work happens when the work item becomes eligible for > execution. e.g. If the workqueue's @max_active is limited and > maximum number of work items are already in flight, a new item will > only get activated after one of the in flight ones retires. > > * execute_start marks the actual starting of execution. > > * execute_end marks the end of execution. > > So, I would look for the matching work function and then try to follow > what happens to it after being scheduled and if it doesn't get > executed what's going on with the target workqueue. > > Thanks.