Re: [patch 3/3] memcg: never OOM when charging huge pages

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Fri, 28 Jan 2011 08:45:40 +0900
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:

> On Thu, 27 Jan 2011 14:47:03 +0100
> Johannes Weiner <hannes@cmpxchg.org> wrote:
> 
> > Huge page coverage should obviously have less priority than the
> > continued execution of a process.
> > 
> > Never kill a process when charging it a huge page fails.  Instead,
> > give up after the first failed reclaim attempt and fall back to
> > regular pages.
> > 
> > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> > ---
> >  mm/memcontrol.c |    7 +++++++
> >  1 files changed, 7 insertions(+), 0 deletions(-)
> > 
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index 17c4e36..2945649 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -1890,6 +1890,13 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
> >  	int csize = max(CHARGE_SIZE, (unsigned long) page_size);
> >  
> >  	/*
> > +	 * Do not OOM on huge pages.  Fall back to regular pages after
> > +	 * the first failed reclaim attempt.
> > +	 */
> > +	if (page_size > PAGE_SIZE)
> > +		oom = false;
> > +
> > +	/*
> >  	 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
> >  	 * in system level. So, allow to go ahead dying process in addition to
> >  	 * MEMDIE process.
> > -- 
> > 1.7.3.5
> > 
> __mem_cgroup_try_charge() has "oom" switch already, so I prefer making callers
> use the switch properly by themselves.
> 

Okay, will do.

-Kame

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