1 files changed, 23 insertions, 15 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e9d33dc..e286e16 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. */