From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: [RFC][PATCH 6/7] memcg: don't need to get a reference to the parent Date: Wed, 3 Apr 2013 17:13:21 +0800 Message-ID: <515BF2B1.9060909@huawei.com> References: <515BF233.6070308@huawei.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <515BF233.6070308@huawei.com> Sender: owner-linux-mm@kvack.org List-ID: Content-Type: text/plain; charset="us-ascii" To: linux-mm@kvack.org Cc: LKML , Cgroups , Tejun Heo , Glauber Costa , Michal Hocko , KAMEZAWA Hiroyuki , Johannes Weiner The cgroup core guarantees it's always safe to access the parent. Signed-off-by: Li Zefan --- mm/memcontrol.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ad576e8..45129cd 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6124,12 +6124,8 @@ static void mem_cgroup_get(struct mem_cgroup *memcg) static void __mem_cgroup_put(struct mem_cgroup *memcg, int count) { - if (atomic_sub_and_test(count, &memcg->refcnt)) { - struct mem_cgroup *parent = parent_mem_cgroup(memcg); + if (atomic_sub_and_test(count, &memcg->refcnt)) call_rcu(&memcg->rcu_freeing, free_rcu); - if (parent) - mem_cgroup_put(parent); - } } static void mem_cgroup_put(struct mem_cgroup *memcg) @@ -6229,14 +6225,6 @@ mem_cgroup_css_online(struct cgroup *cont) res_counter_init(&memcg->res, &parent->res); res_counter_init(&memcg->memsw, &parent->memsw); res_counter_init(&memcg->kmem, &parent->kmem); - - /* - * We increment refcnt of the parent to ensure that we can - * safely access it on res_counter_charge/uncharge. - * This refcnt will be decremented when freeing this - * mem_cgroup(see mem_cgroup_put). - */ - mem_cgroup_get(parent); } else { res_counter_init(&memcg->res, NULL); res_counter_init(&memcg->memsw, NULL); -- 1.8.0.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org