Re: [RFI] Shared accounting for memory resource controller

From: Dhaval Giani
Date: Wed Apr 08 2009 - 03:53:53 EST


On Wed, Apr 08, 2009 at 01:15:01PM +0530, Bharata B Rao wrote:
> On Wed, Apr 8, 2009 at 1:04 PM, KAMEZAWA Hiroyuki
> <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> > On Wed, 8 Apr 2009 13:01:15 +0530
> > Bharata B Rao <bharata.rao@xxxxxxxxx> wrote:
> >
> >> On Wed, Apr 8, 2009 at 12:48 PM, KAMEZAWA Hiroyuki
> >> <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> >> >
> >> > On Wed, 8 Apr 2009 12:41:15 +0530
> >> > Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
> >> > > 3. Using the above, we can then try to (using an algorithm you
> >> > > proposed), try to do some work for figuring out the shared percentage.
> >> > >
> >> > This is the point. At last. Why "# of shared pages" is important ?
> >> >
> >> > I wonder it's better to add new stat file as memory.cacheinfo which helps
> >> > following kind of commands.
> >> >
> >> >  #cacheinfo /cgroups/memory/group01/
> >> >       /usr/lib/libc.so.1     30pages
> >> >       /var/log/messages      1 pages
> >> >       /tmp/xxxxxx            20 pages
> >>
> >> Can I suggest that we don't add new files for additional stats and try
> >> as far as possible to include them in <controller>.stat file. Please
> >> note that we have APIs in libcgroup library which can return
> >> statistics from controllers associated with a cgroup and these APIs
> >> assume that stats are part of <controller>.stat file.
> >>
> > Hmm ? Is there generic assumption as all cgroup has "stat" file ?
>
> No. But I would think if any controller has any stats to export, it
> would do so via <controller>.stat file.
>
> > And libcgroup cause bug if the new entry is added to stat file ?
>
> No. It can cope with new entries being added to stat file as long as
> they appear as (name, value) pairs.
>

And if it does not, we should fix it to cope up with it. But I agree
with bharata, we should avoid adding new files, and try to use the stat
file.

thanks,
--
regards,
Dhaval
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