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Message-ID: <6599ad830804031058l1e2a7ad9p56cff47dca738d79@mail.gmail.com>
Date: Thu, 3 Apr 2008 10:58:20 -0700
From: "Paul Menage" <menage@google.com>
To: "Balbir Singh" <balbir@linux.vnet.ibm.com>
Subject: Re: [-mm] Add an owner to the mm_struct (v7)
Cc: "Pavel Emelianov" <xemul@openvz.org>, "Hugh Dickins" <hugh@veritas.com>,
       "Sudhir Kumar" <skumar@linux.vnet.ibm.com>,
       "YAMAMOTO Takashi" <yamamoto@valinux.co.jp>, lizf@cn.fujitsu.com,
       linux-kernel@vger.kernel.org, taka@valinux.co.jp, linux-mm@kvack.org,
       "David Rientjes" <rientjes@google.com>,
       "Andrew Morton" <akpm@linux-foundation.org>,
       "KAMEZAWA Hiroyuki" <kamezawa.hiroyu@jp.fujitsu.com>
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On Thu, Apr 3, 2008 at 10:44 AM, Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
>  +
>  +       /*
>  +        * If there are other users of the mm and the owner (us) is exiting
>  +        * we need to find a new owner to take on the responsibility.
>  +        * When we use thread groups (CLONE_THREAD), the thread group
>  +        * leader is kept around in zombie state, even after it exits.
>  +        * delay_group_leader() ensures that if the group leader is around
>  +        * we need not select a new owner.
>  +        */

Hmm, is this new check for delay_group_leader() safe? Won't we have
called exit_cgroup() by this point, and hence be reassigned to the
root cgroup? And so mm->owner->cgroups won't point to the right place?

Paul