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Date: Tue, 18 Aug 2009 10:26:36 -0400
From: Vivek Goyal <vgoyal@redhat.com>
To: Ryo Tsuruta <ryov@valinux.co.jp>
Cc: linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org,
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Subject: Re: [PATCH 18/24] blkio_cgroup patches from Ryo to track async
	bios.
Message-ID: <20090818142636.GA7367@redhat.com>
References: <1250451046-9966-1-git-send-email-vgoyal@redhat.com> <1250451046-9966-19-git-send-email-vgoyal@redhat.com> <20090818.204212.59676649.ryov@valinux.co.jp>
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On Tue, Aug 18, 2009 at 08:42:12PM +0900, Ryo Tsuruta wrote:
> Hi Vivek,
> 
> Vivek Goyal <vgoyal@redhat.com> wrote:
> > o blkio_cgroup patches from Ryo to track async bios.
> > 
> > o Fernando is also working on another IO tracking mechanism. We are not
> >   particular about any IO tracking mechanism. This patchset can make use
> >   of any mechanism which makes it to upstream. For the time being making
> >   use of Ryo's posting.
> 
> The patch attached with your mail is obsolete and it may potentially
> cause a deadlock when lock_page_cgroup() is called under radix_tree->lock.
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e767e0561d7fd2333df1921f1ab4176211f9036b
> 
> The latest blkio-cgroup fixes the above issue and reduces IO tracking
> overhead since lock_page_cgroup() is no longer used. I would recommend
> to update to the latest version.
> 

Hi Ryo,

Thanks. In next posting I will move to latest version of io tracking
patches.

> And I have a suggestion, how about moving get_cgroup_from_page() to
> biotrack.c, I think this function would be useful for people who
> want to make use of the IO tracking mechanism.
> 
> Please let me know your opinion.

Makes sense. In next posting, will move get_cgroup_from_page() to biotrack.c.

Thanks
Vivek