Re: [patch 1/3] mm: memcontrol: take a css reference for each charged page

Michal Hocko
2014-10-08T13:29:27Z

On Wed 08-10-14 15:27:54, Michal Hocko wrote:
> On Sat 20-09-14 16:00:33, Johannes Weiner wrote:
[...]
> > @@ -2803,8 +2808,10 @@ static void memcg_uncharge_kmem(struct mem_cgroup *memcg,
> > page_counter_uncharge(&memcg->memsw, nr_pages);
> >
>
> Wouldn't a single out_css_put be more readable? I was quite confused
> when I start reading the patch before I saw the next hunk.

Ohh, this will go away in the next patch. Ignore this.

>
> > /* Not down to 0 */
> > - if (page_counter_uncharge(&memcg->kmem, nr_pages))
> goto out_css_put;
>
> > + if (page_counter_uncharge(&memcg->kmem, nr_pages)) {
> > + css_put_many(&memcg->css, nr_pages);
> > return;
> > + }
> >
> > /*
> > * Releases a reference taken in kmem_cgroup_css_offline in case
> > @@ -2816,6 +2823,8 @@ static void memcg_uncharge_kmem(struct mem_cgroup *memcg,
> > */
> > if (memcg_kmem_test_and_clear_dead(memcg))
> > css_put(&memcg->css);
> > +
>
> out_css_put:
> > + css_put_many(&memcg->css, nr_pages);
> > }
> >
> > /*
> --
> Michal Hocko
> SUSE Labs

--
Michal Hocko
SUSE Labs