From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754416AbZEYJrU (ORCPT ); Mon, 25 May 2009 05:47:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752638AbZEYJrN (ORCPT ); Mon, 25 May 2009 05:47:13 -0400 Received: from e23smtp02.au.ibm.com ([202.81.31.144]:46840 "EHLO e23smtp02.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752163AbZEYJrM (ORCPT ); Mon, 25 May 2009 05:47:12 -0400 Date: Mon, 25 May 2009 15:17:04 +0530 From: Dhaval Giani To: Li Zefan Cc: KAMEZAWA Hiroyuki , Andrew Morton , Paul Menage , LKML , Linux Containers , Balbir Singh , libcg-devel@lists.sourceforge.net Subject: Re: [PATCH] cgroups: handle failure of cgroup_populate_dir() at mount/remount Message-ID: <20090525094704.GA5709@linux.vnet.ibm.com> Reply-To: Dhaval Giani References: <4A16153C.2080004@cn.fujitsu.com> <20090522172545.1e5e5f81.kamezawa.hiroyu@jp.fujitsu.com> <4A1663C2.4080401@cn.fujitsu.com> <20090522173421.ecacb40e.kamezawa.hiroyu@jp.fujitsu.com> <20090522091034.GC8696@linux.vnet.ibm.com> <4A1A6192.6050608@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A1A6192.6050608@cn.fujitsu.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 25, 2009 at 05:14:58PM +0800, Li Zefan wrote: > Dhaval Giani wrote: > > On Fri, May 22, 2009 at 05:34:21PM +0900, KAMEZAWA Hiroyuki wrote: > >> On Fri, 22 May 2009 16:35:14 +0800 > >> Li Zefan wrote: > >> > >>> KAMEZAWA Hiroyuki wrote: > >>>> On Fri, 22 May 2009 11:00:12 +0800 > >>>> Li Zefan wrote: > >>>> > >>>>> Now we have 'stat' file in both memory and cpuacct subsystems. If we > >>>>> mount these 2 subsystems with option 'noprefix', the creation of 'stat' > >>>>> file for cpuacct will fail, but without any notificatin to the user. > >>>>> > >>>>> With this patch, we fail the mount/remount in this case. > >>>>> > >>>> Hm, shouldn't we allow "noprefix" to be effective only agaisnt cpuset ? > >>>> I think it's just for backward-compatibility of cpuset. > >>>> (I don't like the option at all.) > >>>> > >>> Yes, this mount option was introduced for cpuset. But it has been here for > >>> a long time and people may use it when mounting other cgroup subsystems, > >>> then is it OK to change to restrict its use within cpuset only? > >> Asking libcgroup people may be appropriate...added CC. > > > > We just realized that we were not handling the noprefix usage in > > I guess handling noprefix will increase complexity of libcgroup? since we > can't figure out which subsystem the file belongs to by looking at the > prefix of the file. > Yes, but that should be handled with the next set of features planned for the library. > > libcgroup. From the pov of the library, the option should either not > > exist for any subsystem or for all of them. Anything else would mean > > having to add special cases. > > > > I don't see how to totally remove 'noprefix' while keep the backward > compatibility of cpuset, so I think we have to reserve it, and fix > name collision caused by this option. I agree with you. -- regards, Dhaval