1 files changed, 11 insertions, 23 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1262a8bc402b..96cd9ebefb2c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2678,15 +2678,13 @@ static int mem_cgroup_move_parent(struct page *page,
                                   struct mem_cgroup *child,
                                   gfp_t gfp_mask)
 {
-        struct cgroup *cg = child->css.cgroup;
-        struct cgroup *pcg = cg->parent;
         struct mem_cgroup *parent;
         unsigned int nr_pages;
         unsigned long uninitialized_var(flags);
         int ret;
 
         /* Is ROOT ? */
-        if (!pcg)
+        if (mem_cgroup_is_root(child))
                 return -EINVAL;
 
         ret = -EBUSY;
@@ -2697,33 +2695,23 @@ static int mem_cgroup_move_parent(struct page *page,
 
         nr_pages = hpage_nr_pages(page);
 
-        parent = mem_cgroup_from_cont(pcg);
-        if (!parent->use_hierarchy) {
-                ret = __mem_cgroup_try_charge(NULL,
-                                        gfp_mask, nr_pages, &parent, false);
-                if (ret)
-                        goto put_back;
-        }
+        parent = parent_mem_cgroup(child);
+        /*
+         * If no parent, move charges to root cgroup.
+         */
+        if (!parent)
+                parent = root_mem_cgroup;
 
         if (nr_pages > 1)
                 flags = compound_lock_irqsave(page);
 
-        if (parent->use_hierarchy) {
-                ret = mem_cgroup_move_account(page, nr_pages,
-                                        pc, child, parent, false);
-                if (!ret)
-                        __mem_cgroup_cancel_local_charge(child, nr_pages);
-        } else {
-                ret = mem_cgroup_move_account(page, nr_pages,
-                                        pc, child, parent, true);
-
-                if (ret)
-                        __mem_cgroup_cancel_charge(parent, nr_pages);
-        }
+        ret = mem_cgroup_move_account(page, nr_pages,
+                                pc, child, parent, false);
+        if (!ret)
+                __mem_cgroup_cancel_local_charge(child, nr_pages);
 
         if (nr_pages > 1)
                 compound_unlock_irqrestore(page, flags);
-put_back:
         putback_lru_page(page);
 put:
         put_page(page);