From mboxrd@z Thu Jan  1 00:00:00 1970
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
Subject: Re: IO controller discussion (Was: Re: [PATCH 01/10] Documentation)
Date: Tue, 21 Apr 2009 10:16:17 +0900
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To: Andrea Righi <righi.andrea-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: paolo.valente-rcYM44yAMweonA0d6jMUrA@public.gmane.org, fernando-w0OK63jvRlAuJ+9fw/WgBHgSJqDPrsil@public.gmane.org, dhaval-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, oz-kernel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, fchecconi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, jmoyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, arozansk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, menage-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, Balbir Singh <balbir-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
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On Sun, 19 Apr 2009 17:53:59 +0200
Andrea Righi <righi.andrea-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > 
> > Got a question for you. Does memory controller already have the per cgroup
> > dirty pages limit? If no, has this been discussed in the past? if yes,
> > what was the conclsion?
> 

IMHO, dirty page handling and I/O throttling is a different problem.

 - A task (or cgroup) which makes the page dirty
 and
 - A task (or cgroup) to which a page is accounted

Is different from each other, in general.

I have a plan to add dirty_ratio to memcg, but it's for avoiding massive stavation in
memory reclaim, not for I/O control.

If you want to implement I/O throttle in MM layer, plz don't depend on memcg.
The perpose is different.

Thanks,
-Kame