Message-ID: <50AB2D2A.1040604@jp.fujitsu.com>
Date: Tue, 20 Nov 2012 16:11:38 +0900
From: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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To: Tejun Heo <tj@kernel.org>
CC: daniel.wagner@bmw-carit.de, srivatsa.bhat@linux.vnet.ibm.com,
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        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/8] cgroup: add cgroup->id
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(2012/11/20 16:08), Tejun Heo wrote:
> Hello, Kamezawa.
>
> On Tue, Nov 20, 2012 at 04:05:51PM +0900, Kamezawa Hiroyuki wrote:
>> BTW, css's ID was limited to 65535 to be encoded in 2bytes.
>> If we use INT, this will increase size of swap_cgroup.
>> (2bytes per page => 4bytes per page) It's preallocated at swapon()
>> because allocating memory dynamically when we swap a memory is not good.
>>
>> Do we really need 4bytes for ID ? If so, swap_cgroup should be totally re-designed.
>
> That's a memcg restriction which shouldn't have been imposed on cgroup
> core from the beginning.  What memcg should do is rejecting to become
> online from ->css_onilne() if cgrp->id is out of the range it can
> handle.
>

Hmm. I'll think a little and consider a patch to remove memcg's refcnt.


Thanks,
-Kame

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