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authorTejun Heo <tj@kernel.org>2014-05-04 15:09:13 -0400
committerTejun Heo <tj@kernel.org>2014-05-04 15:09:13 -0400
commit7d699ddb2b181a2c76e5ea18b1bdf102c4bebe4b (patch)
tree0811810b37ff735921b689aa1ca273ecf253e29c /mm
parent69dfa00ccb72a37f3810687ca110e5a8154c6eed (diff)
downloadop-kernel-dev-7d699ddb2b181a2c76e5ea18b1bdf102c4bebe4b.zip
op-kernel-dev-7d699ddb2b181a2c76e5ea18b1bdf102c4bebe4b.tar.gz
cgroup, memcg: allocate cgroup ID from 1
Currently, cgroup->id is allocated from 0, which is always assigned to the root cgroup; unfortunately, memcg wants to use ID 0 to indicate invalid IDs and ends up incrementing all IDs by one. It's reasonable to reserve 0 for special purposes. This patch updates cgroup core so that ID 0 is not used and the root cgroups get ID 1. The ID incrementing is removed form memcg. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'mm')
-rw-r--r--mm/memcontrol.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 29501f0..1d0b297 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -527,18 +527,14 @@ static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
{
- /*
- * The ID of the root cgroup is 0, but memcg treat 0 as an
- * invalid ID, so we return (cgroup_id + 1).
- */
- return memcg->css.cgroup->id + 1;
+ return memcg->css.cgroup->id;
}
static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
{
struct cgroup_subsys_state *css;
- css = css_from_id(id - 1, &memory_cgrp_subsys);
+ css = css_from_id(id, &memory_cgrp_subsys);
return mem_cgroup_from_css(css);
}
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