Re: [RFI] Shared accounting for memory resource controller

From: KAMEZAWA Hiroyuki
Date: Wed Apr 08 2009 - 03:09:26 EST


On Wed, 8 Apr 2009 12:34:01 +0530
Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:

> * KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2009-04-08 15:15:29]:
>
> > On Wed, 8 Apr 2009 10:59:04 +0530
> > Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
> >
> >
> > > > no serious intention.
> > > > Just because you wrote "expect the user to account all cached pages as shared" ;)
> > > >
> > >
> > > OK, I noticed another thing, our RSS accounting is not RSS per-se, it
> > > includes only anon RSS, file backed pages are accounted as cached.
> > > I'll send out a patch to see if we can include anon RSS as well.
> > >
> >
> > I think we can't do it in memcg layer without new-hook because file caches
> > are added to radix-tree before mapped.
> >
> > mm struct has anon_rss and file_rss coutners. Then, you can show
> > sum of total maps of file pages. maybe.
> >
>
> Yes, correct and that is a hook worth adding, IMHO. Better statistics
> are critical and it will also help us with the shared memory
> accounting. Without that we can't account for file rss in the memory
> cgroup.
>
Finally, you'll be asked "is it necessary ?", if the cost is big.
>From my point of view, I can't see what new information it will give us.
But maybe useful because the user can avoid some calculation.

Cheers,
-Kame

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