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authorTejun Heo <tj@kernel.org>2014-05-04 15:09:14 -0400
committerTejun Heo <tj@kernel.org>2014-05-04 15:09:14 -0400
commit15a4c835e4ed3e60dd68727cd1907e3dd89563f4 (patch)
tree849cef1af88267720ec75def1c05ffe0f41e310e /mm
parentddfcadab35dda6e5bc23ccf1c3055ecb63a71e49 (diff)
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cgroup, memcg: implement css->id and convert css_from_id() to use it
Until now, cgroup->id has been used to identify all the associated csses and css_from_id() takes cgroup ID and returns the matching css by looking up the cgroup and then dereferencing the css associated with it; however, now that the lifetimes of cgroup and css are separate, this is incorrect and breaks on the unified hierarchy when a controller is disabled and enabled back again before the previous instance is released. This patch adds css->id which is a subsystem-unique ID and converts css_from_id() to look up by the new css->id instead. memcg is the only user of css_from_id() and also converted to use css->id instead. For traditional hierarchies, this shouldn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jianyu Zhan <nasa4836@gmail.com> Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'mm')
-rw-r--r--mm/memcontrol.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1d0b29715b73..c3f82f69ef58 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -527,7 +527,7 @@ static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
{
- return memcg->css.cgroup->id;
+ return memcg->css.id;
}
static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
@@ -6401,7 +6401,7 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css)
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(css));
- if (css->cgroup->id > MEM_CGROUP_ID_MAX)
+ if (css->id > MEM_CGROUP_ID_MAX)
return -ENOSPC;
if (!parent)