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

Glauber Costa
2013-04-03T13:05:39Z

On 04/03/2013 01:12 PM, 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;
> + }
>
> new_cachep = kmem_cache_dup(memcg, cachep);
> if (new_cachep == NULL) {
> new_cachep = cachep;
> + css_put(&memcg->css);
> goto out;
> }
>
> - mem_cgroup_get(memcg);
> atomic_set(&new_cachep->memcg_params->nr_pages , 0);
>
> cachep->memcg_params->memcg_caches[idx] = new_cachep;
> @@ -3449,8 +3451,6 @@ static void memcg_create_cache_work_func(struct work_struct *w)
>
> cw = container_of(w, struct create_work, work);
> memcg_create_kmem_cache(cw->memcg, cw->cachep);
> - /* Drop the reference gotten when we enqueued. */
> - css_put(&cw->memcg->css);
> kfree(cw);
> }
>
>
At first look, this one seems all right.

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