diff options
| author | Michal Hocko <mhocko@suse.cz> | 2012-10-26 13:37:29 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2012-10-29 16:22:21 -0700 |
| commit | d842301181d9a4486aa24720ed4f96018b213292 (patch) | |
| tree | bd2132cd966aaeaa91aaa5ca85cfc24f29061375 /mm/memcontrol.c | |
| parent | c26251f9f06d27d1941229d237aca44a0e7b4e42 (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.c | 6 |
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); |