Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761511AbYGAVzk (ORCPT ); Tue, 1 Jul 2008 17:55:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755190AbYGAVz0 (ORCPT ); Tue, 1 Jul 2008 17:55:26 -0400 Received: from E23SMTP02.au.ibm.com ([202.81.18.163]:53747 "EHLO e23smtp02.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761306AbYGAVzX (ORCPT ); Tue, 1 Jul 2008 17:55:23 -0400 Date: Wed, 2 Jul 2008 03:24:48 +0530 From: Dhaval Giani To: Andrea Righi Cc: Li Zefan , Paul Menage , Andrew Morton , Balbir Singh , Sudhir Kumar , lkml , containers@lists.osdl.org, Paul Jackson Subject: Re: Attaching PID 0 to a cgroup Message-ID: <20080701215448.GD5893@linux.vnet.ibm.com> Reply-To: Dhaval Giani References: <20080701094545.GD3925@linux.vnet.ibm.com> <20080701094734.GE3925@linux.vnet.ibm.com> <486A06B7.7020906@cn.fujitsu.com> <486AA62F.40503@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <486AA62F.40503@gmail.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 Content-Length: 2082 Lines: 67 On Tue, Jul 01, 2008 at 11:48:31PM +0200, Andrea Righi wrote: > Li Zefan wrote: >> CC: Paul Jackson >> >> Dhaval Giani wrote: >>> [put in the wrong alias for containers list correcting it.] >>> >>> On Tue, Jul 01, 2008 at 03:15:45PM +0530, Dhaval Giani wrote: >>>> Hi Paul, >>>> >>>> Attaching PID 0 to a cgroup caused the current task to be attached to >>>> the cgroup. Looking at the code, >>>> >> >> [...] >> >>>> I was wondering, why this was done. It seems to be unexpected behavior. >>>> Wouldn't something like the following be a better response? (I've used >>>> EINVAL, but I can change it to ESRCH if that is better.) >>>> >> >> Why is it unexpected? it follows the behavior of cpuset, so this patch will >> break backward compatibility of cpuset. >> >> But it's better to document this. >> >> ----------------------------------------- >> >> Document the following cgroup usage: >> # echo 0 > /dev/cgroup/tasks >> >> Signed-off-by: Li Zefan >> --- >> cgroups.txt | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/Documentation/cgroups.txt b/Documentation/cgroups.txt >> index 824fc02..213f533 100644 >> --- a/Documentation/cgroups.txt >> +++ b/Documentation/cgroups.txt >> @@ -390,6 +390,10 @@ If you have several tasks to attach, you have to do it one after another: >> ... >> # /bin/echo PIDn > tasks >> +You can attach the current task by echoing 0: >> + >> +# /bin/echo 0 > tasks >> + >> 3. Kernel API >> ============= > > Wouldn't be more meaningful to specify the bash's builtin echo here > even if it doesn't opportunely handle write() errors? > > Using /bin/echo would attach /bin/echo itself to the cgroup, that just > exists, so it seems like a kind of noop, isn't it? > Yes, you are right. this example should use bash's builtin echo. -- regards, Dhaval -- 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/