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

Li Zefan
2013-04-03T09:14:11Z

Now memcg has the same life cycle as the corresponding cgroup.
Kill the useless refcnt.

Signed-off-by: Li Zefan <lizefan@huawei.com>
---
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

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