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Date: Fri, 14 Sep 2012 15:28:40 -0400
From: Vivek Goyal <vgoyal@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
        linux-kernel@vger.kernel.org, Li Zefan <lizefan@huawei.com>,
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        "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
        Serge Hallyn <serge.hallyn@ubuntu.com>
Subject: Re: [RFC] cgroup TODOs
Message-ID: <20120914192840.GG6221@redhat.com>
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 <20120914180754.GF6221@redhat.com>
 <20120914185324.GI17747@google.com>
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On Fri, Sep 14, 2012 at 11:53:24AM -0700, Tejun Heo wrote:

[..]
> In addition, for some resources, granularity beyond certain point
> simply doesn't work.  Per-service granularity might make sense for cpu
> but applying it by default would be silly for blkio.

Hmm.., In that case how libvirt will make use of blkio in the proposed
scheme. We can't disable blkio nesting at "system" level. So We will
have to disable it at each service level  except "libvirtd" so that
libvirt can use blkio for its virtual machines.

That means blkio will see each service in a cgroup of its own and if 
that does not make sense by default, its a problem. In the existing
scheme, atleast every service does not show up in its cgroup from
blkio point of view. Everthig is in root and libvirt can create its
own cgroups, keeping number of cgroups small.

Thanks
Vivek