Re: [RFC][PATCH 2/7] memcg: don't use mem_cgroup_get() when creating a kmemcg cache

Michal Hocko
2013-04-05T13:46:35Z

On Fri 05-04-13 14:51:10, KAMEZAWA Hiroyuki wrote:
> (2013/04/03 18:12), Li Zefan wrote:
> > Use css_get()/css_put() instead of mem_cgroup_get()/mem_cgroup_put().
> >
> > Signed-off-by: Li Zefan <lizefan@huawei.com>
> > ---
> > mm/memcontrol.c | 10 +++++-----
> > 1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index 43ca91d..dafacb8 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -3191,7 +3191,7 @@ void memcg_release_cache(struct kmem_cache *s)
> > list_del(&s->memcg_params->list);
> > mutex_unlock(&memcg->slab_caches_mutex);
> >
> > - mem_cgroup_put(memcg);
> > + css_put(&memcg->css);
> > out:
> > kfree(s->memcg_params);
> > }
> > @@ -3350,16 +3350,18 @@ static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
> >
> > mutex_lock(&memcg_cache_mutex);
> > new_cachep = cachep->memcg_params->memcg_caches[idx];
> > - if (new_cachep)
> > + if (new_cachep) {
> > + css_put(&memcg->css);
> > goto out;
> > + }
>
> Where css_get() against this is done ?

As glauber explained in another email in this thread. It was
__memcg_create_cache_enqueue which took the reference.
--
Michal Hocko
SUSE Labs