Re: [PATCH 4/7] memcg : fix charge function of THP allocation.

From: KAMEZAWA Hiroyuki
Date: Thu Jan 27 2011 - 18:44:46 EST


On Thu, 27 Jan 2011 11:34:38 +0100
Johannes Weiner <hannes@xxxxxxxxxxx> wrote:

> On Fri, Jan 21, 2011 at 03:44:30PM +0900, KAMEZAWA Hiroyuki wrote:
> > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> >
> > When THP is used, Hugepage size charge can happen. It's not handled
> > correctly in mem_cgroup_do_charge(). For example, THP can fallback
> > to small page allocation when HUGEPAGE allocation seems difficult
> > or busy, but memory cgroup doesn't understand it and continue to
> > try HUGEPAGE charging. And the worst thing is memory cgroup
> > believes 'memory reclaim succeeded' if limit - usage > PAGE_SIZE.
> >
> > By this, khugepaged etc...can goes into inifinite reclaim loop
> > if tasks in memcg are busy.
> >
> > After this patch
> > - Hugepage allocation will fail if 1st trial of page reclaim fails.
> > - distinguish THP allocaton from Bached allocation.
>
> This does too many things at once. Can you split this into more
> patches where each one has a single objective? Thanks.
>

Sure, will do.

I'm now testing new ones.

Thanks,
-Kame

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