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Date: Wed, 10 Dec 2008 01:00:42 -0800
Message-ID: <6599ad830812100100i54132600he52504b4785542ec@mail.gmail.com>
Subject: Re: [RFC][PATCH 1/4] New css->refcnt implementation.
From: Paul Menage <menage@google.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
       "nishimura@mxp.nes.nec.co.jp" <nishimura@mxp.nes.nec.co.jp>,
       "balbir@linux.vnet.ibm.com" <balbir@linux.vnet.ibm.com>,
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On Fri, Dec 5, 2008 at 3:24 AM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@jp.fujitsu.com> wrote:
>> The basic rule is that you're only supposed to increment the css
>> refcount if you have:
>>
>> - a reference to a task in the cgroup (that is pinned via task_lock()
>> so it can't be moved away)
>> or
>> - an existing reference to the css
>>
> My problem is that we can do css_get() after pre_destroy() and
> css's refcnt goes down to 0.

But where are you getting the reference from in order to do css_get()?
Which call in mem cgroup are you concerned about?

Paul