Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753775AbZDVDLU (ORCPT ); Tue, 21 Apr 2009 23:11:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752433AbZDVDLF (ORCPT ); Tue, 21 Apr 2009 23:11:05 -0400 Received: from smtp-out.google.com ([216.239.45.13]:27832 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750951AbZDVDLD convert rfc822-to-8bit (ORCPT ); Tue, 21 Apr 2009 23:11:03 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=mime-version:in-reply-to:references:date:message-id:subject:from:to: cc:content-type:content-transfer-encoding:x-system-of-record; b=HroNd5lWfjyJFUZ0p70Glx0Efb74YQCHdeEnnMaN9oO4C4urNDWBKohq5xN6LYcvS ZCUcGI4G26QoxUZY6aZ8w== MIME-Version: 1.0 In-Reply-To: <49EE895A.1060101@cn.fujitsu.com> References: <1236823015-4183-1-git-send-email-vgoyal@redhat.com> <49DF1256.7080403@cn.fujitsu.com> <20090413130958.GB18007@redhat.com> <49EE895A.1060101@cn.fujitsu.com> Date: Tue, 21 Apr 2009 20:10:56 -0700 Message-ID: Subject: Re: [RFC] IO Controller From: Nauman Rafique To: Gui Jianfeng Cc: Vivek Goyal , dpshah@google.com, lizf@cn.fujitsu.com, mikew@google.com, fchecconi@gmail.com, paolo.valente@unimore.it, jens.axboe@oracle.com, ryov@valinux.co.jp, fernando@intellilink.co.jp, s-uchida@ap.jp.nec.com, taka@valinux.co.jp, arozansk@redhat.com, jmoyer@redhat.com, oz-kernel@redhat.com, dhaval@linux.vnet.ibm.com, balbir@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, akpm@linux-foundation.org, menage@google.com, peterz@infradead.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1969 Lines: 70 On Tue, Apr 21, 2009 at 8:04 PM, Gui Jianfeng wrote: > Vivek Goyal wrote: >> On Fri, Apr 10, 2009 at 05:33:10PM +0800, Gui Jianfeng wrote: >>> Vivek Goyal wrote: >>>> Hi All, >>>> >>>> Here is another posting for IO controller patches. Last time I had posted >>>> RFC patches for an IO controller which did bio control per cgroup. >>> ? Hi Vivek, >>> >>> ? I got the following OOPS when testing, can't reproduce again :( >>> >> >> Hi Gui, >> >> Thanks for the report. Will look into it and see if I can reproduce it. > > ?Hi Vivek, > > ?The following script can reproduce the bug in my box. > > #!/bin/sh > > mkdir /cgroup > mount -t cgroup -o io io /cgroup > mkdir /cgroup/test1 > mkdir /cgroup/test2 > > echo cfq > /sys/block/sda/queue/scheduler > echo 7 > /cgroup/test1/io.ioprio > echo 1 > /cgroup/test2/io.ioprio > echo 1 > /proc/sys/vm/drop_caches > dd if=1000M.1 of=/dev/null & > pid1=$! > echo $pid1 > echo $pid1 > /cgroup/test1/tasks > dd if=1000M.2 of=/dev/null > pid2=$! > echo $pid2 > echo $pid2 > /cgroup/test2/tasks > > > rmdir /cgroup/test1 > rmdir /cgroup/test2 > umount /cgroup > rmdir /cgroup Yes, this bug happens when we move a task from a cgroup to another one, and delete the cgroup. Since the actual move to the new cgroup is performed in a delayed fashion, if the cgroup is removed before another request from the task is seen (and the actual move is performed) , it results in a hit on BUG_ON. I am working on a patch that will solve this problem and a few others; basically it would do ref counting for io_group structure. I am having a few problems with it at the moment; will post the patch as soon as I can get it to work. > > -- > Regards > Gui Jianfeng > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/