Re: [RFC][PATCH 7/7] memcg: kill memcg refcnt

Michal Hocko
2013-04-04T15:35:00Z

On Wed 03-04-13 17:14:11, Li Zefan wrote:
> Now memcg has the same life cycle as the corresponding cgroup.
> Kill the useless refcnt.
>
> Signed-off-by: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>

Acked-by: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>

Thanks!

> ---
> mm/memcontrol.c | 24 +-----------------------
> 1 file changed, 1 insertion(+), 23 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 45129cd..9714a16 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -297,8 +297,6 @@ struct mem_cgroup {
> bool oom_lock;
> atomic_t under_oom;
>
> - atomic_t refcnt;
> -
> int swappiness;
> /* OOM-Killer disable */
> int oom_kill_disable;
> @@ -501,9 +499,6 @@ enum res_type {
> */
> static DEFINE_MUTEX(memcg_create_mutex);
>
> -static void mem_cgroup_get(struct mem_cgroup *memcg);
> -static void mem_cgroup_put(struct mem_cgroup *memcg);
> -
> static inline
> struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s)
> {
> @@ -6117,22 +6112,6 @@ static void free_rcu(struct rcu_head *rcu_head)
> schedule_work(&memcg->work_freeing);
> }
>
> -static void mem_cgroup_get(struct mem_cgroup *memcg)
> -{
> - atomic_inc(&memcg->refcnt);
> -}
> -
> -static void __mem_cgroup_put(struct mem_cgroup *memcg, int count)
> -{
> - if (atomic_sub_and_test(count, &memcg->refcnt))
> - call_rcu(&memcg->rcu_freeing, free_rcu);
> -}
> -
> -static void mem_cgroup_put(struct mem_cgroup *memcg)
> -{
> - __mem_cgroup_put(memcg, 1);
> -}
> -
> /*
> * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
> */
> @@ -6192,7 +6171,6 @@ mem_cgroup_css_alloc(struct cgroup *cont)
>
> memcg->last_scanned_node = MAX_NUMNODES;
> INIT_LIST_HEAD(&memcg->oom_notify);
> - atomic_set(&memcg->refcnt, 1);
> memcg->move_charge_at_immigrate = 0;
> mutex_init(&memcg->thresholds_lock);
> spin_lock_init(&memcg->move_lock);
> @@ -6279,7 +6257,7 @@ static void mem_cgroup_css_free(struct cgroup *cont)
>
> mem_cgroup_sockets_destroy(memcg);
>
> - mem_cgroup_put(memcg);
> + call_rcu(&memcg->rcu_freeing, free_rcu);
> }
>
> #ifdef CONFIG_MMU
> --
> 1.8.0.2

--
Michal Hocko
SUSE Labs