Re: [PATCH v3][0/6] memcg: prevent -ENOMEM in pre_destroy()

[Tejun Heo]

Hello, KAME.

On Thu, Jun 28, 2012 at 1:33 AM, Kamezawa Hiroyuki
<kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
>> Ooh, once memcg drops the __DEPRECATED_clear_css_refs, cgroup_rmdir()
>> will mark the cgroup dead before start calling pre_destroy() and none
>> of the above will happen.
>>
>
> Hm, threads which touches memcg should hold memcg's reference count rather
> than css.
> Right ? IIUC, one of reason is a reference from kswapd etc...hm. I'll check
> it.

Not sure I'm following. I meant that css_tryget() will always fail
once pre_destroy() calls being for the cgroup, so no new child or
reference can be created for it after that point.

Thanks.

-- 
tejun
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