Re: [PATCH 3/4] memcg: get rid of percpu_charge_mutex lock

From: Michal Hocko
Date: Fri Jul 22 2011 - 05:21:22 EST


On Fri 22-07-11 08:49:27, KAMEZAWA Hiroyuki wrote:
> On Thu, 21 Jul 2011 14:42:23 +0200
> Michal Hocko <mhocko@xxxxxxx> wrote:
>
> > On Thu 21-07-11 13:47:04, Michal Hocko wrote:
> > > On Thu 21-07-11 19:30:51, KAMEZAWA Hiroyuki wrote:
> > > > On Thu, 21 Jul 2011 09:58:24 +0200
> > > > Michal Hocko <mhocko@xxxxxxx> wrote:
> > [...]
> > > > > --- a/mm/memcontrol.c
> > > > > +++ b/mm/memcontrol.c
> > > > > @@ -2166,7 +2165,8 @@ static void drain_all_stock(struct mem_cgroup *root_mem, bool sync)
> > > > >
> > > > > for_each_online_cpu(cpu) {
> > > > > struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
> > > > > - if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
> > > > > + if (root_mem == stock->cached &&
> > > > > + test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
> > > > > flush_work(&stock->work);
> > > >
> > > > Doesn't this new check handle hierarchy ?
> > > > css_is_ancestor() will be required if you do this check.
> > >
> > > Yes you are right. Will fix it. I will add a helper for the check.
> >
> > Here is the patch with the helper. The above will then read
> > if (mem_cgroup_same_or_subtree(root_mem, stock->cached))
> >
> > ---
> > From b963a9f4dac61044daac49700f84b7819d7c2f53 Mon Sep 17 00:00:00 2001
> > From: Michal Hocko <mhocko@xxxxxxx>
> > Date: Thu, 21 Jul 2011 13:54:13 +0200
> > Subject: [PATCH] memcg: add mem_cgroup_same_or_subtree helper
> >
> > We are checking whether a given two groups are same or at least in the
> > same subtree of a hierarchy at several places. Let's make a helper for
> > it to make code easier to read.
> >
> > Signed-off-by: Michal Hocko <mhocko@xxxxxxx>
>
> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

Thanks

--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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