From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754757Ab0IALKc (ORCPT ); Wed, 1 Sep 2010 07:10:32 -0400 Received: from mx.ij.cx ([212.13.201.15]:59154 "EHLO wes.ijneb.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752379Ab0IALKa (ORCPT ); Wed, 1 Sep 2010 07:10:30 -0400 Date: Wed, 1 Sep 2010 12:10:23 +0100 (BST) From: Mark Hills To: KAMEZAWA Hiroyuki cc: Daisuke Nishimura , linux-kernel@vger.kernel.org, balbir@linux.vnet.ibm.com Subject: Re: cgroup: rmdir() does not complete In-Reply-To: <20100827144225.3190167a.kamezawa.hiroyu@jp.fujitsu.com> Message-ID: References: <20100827095639.6e7297de.nishimura@mxp.nes.nec.co.jp> <20100827113506.2bbbb7b9.kamezawa.hiroyu@jp.fujitsu.com> <20100827123948.b4427a15.nishimura@mxp.nes.nec.co.jp> <20100827144225.3190167a.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mark@pogo.org.uk Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 27 Aug 2010, KAMEZAWA Hiroyuki wrote: > On Fri, 27 Aug 2010 12:39:48 +0900 > Daisuke Nishimura wrote: > > > On Fri, 27 Aug 2010 11:35:06 +0900 > > KAMEZAWA Hiroyuki wrote: > > > > > On Fri, 27 Aug 2010 09:56:39 +0900 > > > Daisuke Nishimura wrote: > > > > > > > > Or is it likely to be some other cause, and how best to find it? > > > > > > > > > What cgroup subsystem did you mount where the directory existed you tried > > > > to rmdir() first ? > > > > If you mounted several subsystems on the same hierarchy, can you mount them > > > > separately to narrow down the cause ? > > > > > > > > > > It seems I can reproduce the issue on mmotm-0811, too. > > > > > > try this. > > > > > > Here, memory cgroup is mounted at /cgroups. > > > == > > > #!/bin/bash -x > > > > > > while sleep 1; do > > > date > > > mkdir /cgroups/test > > > echo 0 > /cgroups/test/tasks > > > echo 300M > /cgroups/test/memory.limit_in_bytes > > > cat /proc/self/cgroup > > > dd if=/dev/zero of=./tmpfile bs=4096 count=100000 > > > echo 0 > /cgroups/tasks > > > cat /proc/self/cgroup > > > rmdir /cgroups/test > > > rm ./tmpfile > > > done > > > == > > > > > > hangs at rmdir. I'm no investigating force_empty. > > > > > Thank you very much for your information. > > > > Some questions. > > > > Is "tmpfile" created on a normal filesystem(e.g. ext3) or tmpfs ? > on ext4. > > > And, how long does it likely to take to cause this problem ? > > very soon. 10-20 loop. I repeated the test above, but did not see a problem after many hundreds of loops. My test was with the same kernel from my original bug report (Fedora 2.6.33.6-147), using memory cgroup only and ext4 filesystem. So it is possible we are experiencing different bugs with similar symptoms. -- Mark