Re: [PATCH] memcg: make memcg's file mapped consistent with globalVM

From: Balbir Singh
Date: Wed Oct 28 2009 - 03:32:25 EST


* KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2009-10-28 16:24:58]:

> On Wed, 28 Oct 2009 12:48:54 +0530
> Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
>
> > * KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2009-10-28 12:16:19]:
> >
> > > Based on mmotm-Oct13 + some patches in -mm queue.
> > >
> > > ==
> > > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> > >
> > > memcg-cleanup-file-mapped-consistent-with-globarl-vm-stat.patch
> > >
> > > In global VM, FILE_MAPPED is used but memcg uses MAPPED_FILE.
> > > This makes grep difficult. Replace memcg's MAPPED_FILE with FILE_MAPPED
> > >
> > > And in global VM, mapped shared memory is accounted into FILE_MAPPED.
> > > But memcg doesn't. fix it.
> >
> > I wanted to explicitly avoid this since I wanted to do an iterative
> > correct accounting of shared memory. The renaming is fine with me
> > since we don't break ABI in user space.
> >
> To do that, FILE_MAPPED is not correct.
> Because MAPPED includes shmem in global VM, no valid reason to do different
> style of counting.

OK, fair enough! Lets count shmem in FILE_MAPPED

>
> For shmem, we have a charge type as MEM_CGROUP_CHARGE_TYPE_SHMEM and
> we can set "PCG_SHMEM" flag onto page_cgroup or some.
> Then, we can count it in explicit way.
>

Apart from shmem, I want to count all memory that is shared (mapcount > 1),
I'll send out an RFC once I have the implementation. For now, I
want to focus on testing memcg a bit more and start looking at some
aspects of dirty accounting.

--
Balbir
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