1 files changed, 23 insertions, 15 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e9d33dc151a5..e286e1603e4f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1077,9 +1077,11 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
                 if (scan >= nr_to_scan)
                         break;
 
-                page = pc->page;
                 if (unlikely(!PageCgroupUsed(pc)))
                         continue;
+
+                page = pc->page;
+
                 if (unlikely(!PageLRU(page)))
                         continue;
 
@@ -2108,6 +2110,7 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
 }
 
 static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
+                                       struct page *page,
                                        struct page_cgroup *pc,
                                        enum charge_type ctype,
                                        int page_size)
@@ -2154,7 +2157,7 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
          * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
          * if they exceeds softlimit.
          */
-        memcg_check_events(mem, pc->page);
+        memcg_check_events(mem, page);
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -2201,6 +2204,7 @@ void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
 
 /**
  * mem_cgroup_move_account - move account of the page
+ * @page: the page
  * @pc: page_cgroup of the page.
  * @from: mem_cgroup which the page is moved from.
  * @to: mem_cgroup which the page is moved to. @from != @to.
@@ -2216,7 +2220,7 @@ void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
  * true, this function does "uncharge" from old cgroup, but it doesn't if
  * @uncharge is false, so a caller should do "uncharge".
  */
-static int mem_cgroup_move_account(struct page_cgroup *pc,
+static int mem_cgroup_move_account(struct page *page, struct page_cgroup *pc,
                                    struct mem_cgroup *from, struct mem_cgroup *to,
                                    bool uncharge, int charge_size)
 {
@@ -2225,7 +2229,7 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
         int ret;
 
         VM_BUG_ON(from == to);
-        VM_BUG_ON(PageLRU(pc->page));
+        VM_BUG_ON(PageLRU(page));
         /*
          * The page is isolated from LRU. So, collapse function
          * will not handle this page. But page splitting can happen.
@@ -2233,7 +2237,7 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
          * hold it.
          */
         ret = -EBUSY;
-        if (charge_size > PAGE_SIZE && !PageTransHuge(pc->page))
+        if (charge_size > PAGE_SIZE && !PageTransHuge(page))
                 goto out;
 
         lock_page_cgroup(pc);
@@ -2273,8 +2277,8 @@ unlock:
         /*
          * check events
          */
-        memcg_check_events(to, pc->page);
-        memcg_check_events(from, pc->page);
+        memcg_check_events(to, page);
+        memcg_check_events(from, page);
 out:
         return ret;
 }
@@ -2283,11 +2287,11 @@ out:
  * move charges to its parent.
  */
 
-static int mem_cgroup_move_parent(struct page_cgroup *pc,
+static int mem_cgroup_move_parent(struct page *page,
+                                  struct page_cgroup *pc,
                                   struct mem_cgroup *child,
                                   gfp_t gfp_mask)
 {
-        struct page *page = pc->page;
         struct cgroup *cg = child->css.cgroup;
         struct cgroup *pcg = cg->parent;
         struct mem_cgroup *parent;
@@ -2317,7 +2321,7 @@ static int mem_cgroup_move_parent(struct page_cgroup *pc,
         if (page_size > PAGE_SIZE)
                 flags = compound_lock_irqsave(page);
 
-        ret = mem_cgroup_move_account(pc, child, parent, true, page_size);
+        ret = mem_cgroup_move_account(page, pc, child, parent, true, page_size);
         if (ret)
                 mem_cgroup_cancel_charge(parent, page_size);
 
@@ -2363,7 +2367,7 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
         if (ret || !mem)
                 return ret;
 
-        __mem_cgroup_commit_charge(mem, pc, ctype, page_size);
+        __mem_cgroup_commit_charge(mem, page, pc, ctype, page_size);
         return 0;
 }
 
@@ -2501,7 +2505,7 @@ __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
         cgroup_exclude_rmdir(&ptr->css);
         pc = lookup_page_cgroup(page);
         mem_cgroup_lru_del_before_commit_swapcache(page);
-        __mem_cgroup_commit_charge(ptr, pc, ctype, PAGE_SIZE);
+        __mem_cgroup_commit_charge(ptr, page, pc, ctype, PAGE_SIZE);
         mem_cgroup_lru_add_after_commit_swapcache(page);
         /*
          * Now swap is on-memory. This means this page may be
@@ -2956,7 +2960,7 @@ int mem_cgroup_prepare_migration(struct page *page,
                 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
         else
                 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
-        __mem_cgroup_commit_charge(mem, pc, ctype, PAGE_SIZE);
+        __mem_cgroup_commit_charge(mem, page, pc, ctype, PAGE_SIZE);
         return ret;
 }
 
@@ -3323,6 +3327,8 @@ static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
         loop += 256;
         busy = NULL;
         while (loop--) {
+                struct page *page;
+
                 ret = 0;
                 spin_lock_irqsave(&zone->lru_lock, flags);
                 if (list_empty(list)) {
@@ -3338,7 +3344,9 @@ static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
                 }
                 spin_unlock_irqrestore(&zone->lru_lock, flags);
 
-                ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
+                page = pc->page;
+
+                ret = mem_cgroup_move_parent(page, pc, mem, GFP_KERNEL);
                 if (ret == -ENOMEM)
                         break;
 
@@ -4956,7 +4964,7 @@ retry:
                         if (isolate_lru_page(page))
                                 goto put;
                         pc = lookup_page_cgroup(page);
-                        if (!mem_cgroup_move_account(pc,
+                        if (!mem_cgroup_move_account(page, pc,
                                         mc.from, mc.to, false, PAGE_SIZE)) {
                                 mc.precharge--;
                                 /* we uncharge from mc.from later. */