Re: [PATCH 1/8] cgroup: add cgroup->id

From: Tejun Heo
Date: Tue Nov 20 2012 - 02:08:45 EST


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.

Thanks.

--
tejun
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