From: Li Zefan Subject: [PATCH v3 6/8] memcg: fail to create cgroup if the cgroup id is too big Date: Mon, 29 Jul 2013 15:09:08 +0800 Message-ID: <51F61514.5080702@huawei.com> References: <51F614B2.6010503@huawei.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <51F614B2.6010503-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Tejun Heo Cc: Andrew Morton , Glauber Costa , KAMEZAWA Hiroyuki , Michal Hocko , Johannes Weiner , LKML , Cgroups , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org memcg requires the cgroup id to be smaller than 65536. This is a preparation to kill css id. Signed-off-by: Li Zefan Acked-by: Michal Hocko --- mm/memcontrol.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 62541f5..ad7d7c9 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -512,6 +512,12 @@ static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) return (memcg == root_mem_cgroup); } +/* + * We restrict the id in the range of [1, 65535], so it can fit into + * an unsigned short. + */ +#define MEM_CGROUP_ID_MAX USHRT_MAX + static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg) { /* @@ -6248,6 +6254,9 @@ mem_cgroup_css_alloc(struct cgroup *cont) long error = -ENOMEM; int node; + if (cont->id > MEM_CGROUP_ID_MAX) + return ERR_PTR(-ENOSPC); + memcg = mem_cgroup_alloc(); if (!memcg) return ERR_PTR(error); -- 1.8.0.2