[dm-devel] Re: [PATCH 18/24] blkio_cgroup patches from Ryo to track async bios.

[Vivek Goyal]

On Tue, Aug 18, 2009 at 08:42:12PM +0900, Ryo Tsuruta wrote:
> Hi Vivek,
> 
> Vivek Goyal <vgoyal at 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 The patch attached with your mail is obsolete and it may potentially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