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From: "Satoshi UCHIDA" <s-uchida@ap.jp.nec.com>
To: "'Paul Menage'" <menage@google.com>
Cc: <linux-kernel@vger.kernel.org>, <containers@lists.linux-foundation.org>,
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Subject: RE: [RFC][patch 8/11][CFQ-cgroup] Control cfq_data per cgroup
Date: Fri, 4 Apr 2008 18:46:53 +0900
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Hi,

> 
> On Thu, Apr 3, 2008 at 11:20 PM, Satoshi UCHIDA <s-uchida@ap.jp.nec.com>
> wrote:
> >
> >  So that you say, root subsystem state maybe keep a reference locally.
> >  For example, create a variable for root subsystem state and
> >  store the pointer when making subsystem state first.
> 
> Yes, that's what I'm suggesting.
> 
> >
> >  However, I think that it is smart to calculate root group of subsystems
> >  when needing its information.
> 
> I don't see why it's better to go through the cgroup subsystem to
> retrieve the reference.
> 

If program have temporary data, it may cause inconsistency.
I think that information should be referred to original(control mechanism).

Information of cgroup is controlled at cgroup subsystem (and cgroupfs_root).
So, I think that it's better to query into cgroup subsystem.

Now, cgroup susbsystem would not change root group.
Therefore, system would also runs by your suggestion.

I will consider this issue.

Thanks,
 Satoshi UCHIDA.