Re: [patch 14/22] memcg: fix direct softlimit reclaim to be calledin limit path

[KAMEZAWA Hiroyuki]

On Tue, 28 Jun 2011 10:08:47 +0200
Michal Hocko <mhocko@xxxxxxx> wrote:

> I am sorry, that I am answering that late but I didn't get to this
> sooner.
> 
> On Mon 27-06-11 16:18:12, Andrew Morton wrote:
> > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> > 
> > commit d149e3b ("memcg: add the soft_limit reclaim in global direct
> > reclaim") adds a softlimit hook to shrink_zones().  By this, soft limit is
> > called as
> > 
> >    try_to_free_pages()
> >        do_try_to_free_pages()
> >            shrink_zones()
> >                mem_cgroup_soft_limit_reclaim()
> > 
> > Then, direct reclaim is memcg softlimit hint aware, now.
> > 
> > But, the memory cgroup's "limit" path can call softlimit shrinker.
> > 
> >    try_to_free_mem_cgroup_pages()
> >        do_try_to_free_pages()
> >            shrink_zones()
> >                mem_cgroup_soft_limit_reclaim()
> > 
> > This will cause a global reclaim when a memcg hits limit.
> 
> Sorry, I do not get it. How does it cause the global reclaim? Did you
> mean soft reclaim?
> 

yes. soft reclaim does global reclaim (in some means). 

Thanks,
-Kame

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