Re: [RFC] Shared page accounting for memory cgroup

From: KAMEZAWA Hiroyuki
Date: Thu Jan 07 2010 - 04:11:30 EST


On Thu, 7 Jan 2010 17:48:14 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> > > "How pages are shared" doesn't show good hints. I don't hear such parameter
> > > is used in production's resource monitoring software.
> > >
> >
> > You mean "How many pages are shared" are not good hints, please see my
> > justification above. With Virtualization (look at KSM for example),
> > shared pages are going to be increasingly important part of the
> > accounting.
> >
>
> Considering KSM, your cuounting style is tooo bad.
>
> You should add
>
> - MEM_CGROUP_STAT_SHARED_BY_KSM
> - MEM_CGROUP_STAT_FOR_TMPFS/SYSV_IPC_SHMEM
>
> counters to memcg rather than scanning. I can help tests.
>
> I have no objections to have above 2 counters. It's informative.
>
> But, memory reclaim can page-out pages even if pages are shared.
> So, "how heavy memcg is" is an independent problem from above coutners.
>

In other words, above counters can show
"What role the memcg play in the system" to some extent.

But I don't express it as "heavy" ....."importance or influence of cgroup" ?

Thanks,
-Kame

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