aboutsummaryrefslogtreecommitdiff
path: root/mm/memcontrol.c
diff options
context:
space:
mode:
authorMichal Hocko <mhocko@suse.cz>2012-10-26 13:37:29 +0200
committerTejun Heo <tj@kernel.org>2012-10-29 16:22:21 -0700
commitd842301181d9a4486aa24720ed4f96018b213292 (patch)
treebd2132cd966aaeaa91aaa5ca85cfc24f29061375 /mm/memcontrol.c
parentc26251f9f06d27d1941229d237aca44a0e7b4e42 (diff)
memcg: root_cgroup cannot reach mem_cgroup_move_parent
The root cgroup cannot be destroyed so we never hit it down the mem_cgroup_pre_destroy path and mem_cgroup_force_empty_write shouldn't even try to do anything if called for the root. This means that mem_cgroup_move_parent doesn't have to bother with the root cgroup and it can assume it can always move charges upwards. Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Tejun Heo <tj@kernel.org> Reviewed-by: Glauber Costa <glommer@parallels.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 07d92b84f44..916132a29b3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2715,9 +2715,7 @@ static int mem_cgroup_move_parent(struct page *page,
unsigned long uninitialized_var(flags);
int ret;
- /* Is ROOT ? */
- if (mem_cgroup_is_root(child))
- return -EINVAL;
+ VM_BUG_ON(mem_cgroup_is_root(child));
ret = -EBUSY;
if (!get_page_unless_zero(page))
@@ -3823,6 +3821,8 @@ static int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
int ret;
+ if (mem_cgroup_is_root(memcg))
+ return -EINVAL;
css_get(&memcg->css);
ret = mem_cgroup_force_empty(memcg);
css_put(&memcg->css);