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Date: Wed, 27 May 2009 09:07:31 +0800
From: Li Zefan <lizf@cn.fujitsu.com>
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To: Paul Menage <menage@google.com>
CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       LKML <linux-kernel@vger.kernel.org>,
       Linux Containers <containers@lists.linux-foundation.org>,
       Balbir Singh <balbir@linux.vnet.ibm.com>
Subject: Re: [PATCH] cgroups: handle failure of cgroup_populate_dir() at 
 mount/remount
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Paul Menage wrote:
> On Fri, May 22, 2009 at 1:25 AM, KAMEZAWA Hiroyuki
> <kamezawa.hiroyu@jp.fujitsu.com> wrote:
>> 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, exposing the "noprefix" option externally was one of the mistakes
> I made when developing cgroups.
> 
> It seems to me really unlikely that anyone is using "noprefix" for

And "noprefix" is not documented in cgroups.txt, so I guess not
many people know this option. Even libcgroup doesn't handle it.

> anything other than implicitly when mounting the "cpuset" filesystem.
> So I'd be inclined to just forbid it if we're mounting more than just
> the cpuset subsystem. A bit of a nasty abstraction violation, but it
> makes more sense overall. The only problem is that someone *might* be
> using it - do we have any way to determine how, and how big do they
> have to be before we care?
> 

I think we can never know..