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-rw-r--r--include/linux/memcontrol.h52
-rw-r--r--mm/mlock.c11
-rw-r--r--mm/swap.c33
-rw-r--r--mm/vmscan.c12
4 files changed, 62 insertions, 46 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index aa5d559853c2..ff02f831e7e1 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -485,6 +485,22 @@ out:
 
 struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);
 
+static inline bool lruvec_holds_page_lru_lock(struct page *page,
+					      struct lruvec *lruvec)
+{
+	pg_data_t *pgdat = page_pgdat(page);
+	const struct mem_cgroup *memcg;
+	struct mem_cgroup_per_node *mz;
+
+	if (mem_cgroup_disabled())
+		return lruvec == &pgdat->__lruvec;
+
+	mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
+	memcg = page_memcg(page) ? : root_mem_cgroup;
+
+	return lruvec->pgdat == pgdat && mz->memcg == memcg;
+}
+
 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
 
 struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm);
@@ -984,6 +1000,14 @@ static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
 	return &pgdat->__lruvec;
 }
 
+static inline bool lruvec_holds_page_lru_lock(struct page *page,
+					      struct lruvec *lruvec)
+{
+	pg_data_t *pgdat = page_pgdat(page);
+
+	return lruvec == &pgdat->__lruvec;
+}
+
 static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
 {
 	return NULL;
@@ -1354,6 +1378,34 @@ static inline void unlock_page_lruvec_irqrestore(struct lruvec *lruvec,
 	spin_unlock_irqrestore(&lruvec->lru_lock, flags);
 }
 
+/* Don't lock again iff page's lruvec locked */
+static inline struct lruvec *relock_page_lruvec_irq(struct page *page,
+		struct lruvec *locked_lruvec)
+{
+	if (locked_lruvec) {
+		if (lruvec_holds_page_lru_lock(page, locked_lruvec))
+			return locked_lruvec;
+
+		unlock_page_lruvec_irq(locked_lruvec);
+	}
+
+	return lock_page_lruvec_irq(page);
+}
+
+/* Don't lock again iff page's lruvec locked */
+static inline struct lruvec *relock_page_lruvec_irqsave(struct page *page,
+		struct lruvec *locked_lruvec, unsigned long *flags)
+{
+	if (locked_lruvec) {
+		if (lruvec_holds_page_lru_lock(page, locked_lruvec))
+			return locked_lruvec;
+
+		unlock_page_lruvec_irqrestore(locked_lruvec, *flags);
+	}
+
+	return lock_page_lruvec_irqsave(page, flags);
+}
+
 #ifdef CONFIG_CGROUP_WRITEBACK
 
 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb);
diff --git a/mm/mlock.c b/mm/mlock.c
index ab164a675c25..55b3b3672977 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -277,16 +277,7 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 			 * so we can spare the get_page() here.
 			 */
 			if (TestClearPageLRU(page)) {
-				struct lruvec *new_lruvec;
-
-				new_lruvec = mem_cgroup_page_lruvec(page,
-						page_pgdat(page));
-				if (new_lruvec != lruvec) {
-					if (lruvec)
-						unlock_page_lruvec_irq(lruvec);
-					lruvec = lock_page_lruvec_irq(page);
-				}
-
+				lruvec = relock_page_lruvec_irq(page, lruvec);
 				del_page_from_lru_list(page, lruvec,
 							page_lru(page));
 				continue;
diff --git a/mm/swap.c b/mm/swap.c
index ba9fc21b24ea..2cca7141470c 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -210,19 +210,12 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 
 	for (i = 0; i < pagevec_count(pvec); i++) {
 		struct page *page = pvec->pages[i];
-		struct lruvec *new_lruvec;
 
 		/* block memcg migration during page moving between lru */
 		if (!TestClearPageLRU(page))
 			continue;
 
-		new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
-		if (lruvec != new_lruvec) {
-			if (lruvec)
-				unlock_page_lruvec_irqrestore(lruvec, flags);
-			lruvec = lock_page_lruvec_irqsave(page, &flags);
-		}
-
+		lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
 		(*move_fn)(page, lruvec);
 
 		SetPageLRU(page);
@@ -918,17 +911,12 @@ void release_pages(struct page **pages, int nr)
 		}
 
 		if (PageLRU(page)) {
-			struct lruvec *new_lruvec;
-
-			new_lruvec = mem_cgroup_page_lruvec(page,
-							page_pgdat(page));
-			if (new_lruvec != lruvec) {
-				if (lruvec)
-					unlock_page_lruvec_irqrestore(lruvec,
-									flags);
+			struct lruvec *prev_lruvec = lruvec;
+
+			lruvec = relock_page_lruvec_irqsave(page, lruvec,
+									&flags);
+			if (prev_lruvec != lruvec)
 				lock_batch = 0;
-				lruvec = lock_page_lruvec_irqsave(page, &flags);
-			}
 
 			VM_BUG_ON_PAGE(!PageLRU(page), page);
 			__ClearPageLRU(page);
@@ -1033,15 +1021,8 @@ void __pagevec_lru_add(struct pagevec *pvec)
 
 	for (i = 0; i < pagevec_count(pvec); i++) {
 		struct page *page = pvec->pages[i];
-		struct lruvec *new_lruvec;
-
-		new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
-		if (lruvec != new_lruvec) {
-			if (lruvec)
-				unlock_page_lruvec_irqrestore(lruvec, flags);
-			lruvec = lock_page_lruvec_irqsave(page, &flags);
-		}
 
+		lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
 		__pagevec_lru_add_fn(page, lruvec);
 	}
 	if (lruvec)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b27b5dba3fdd..60705ea598ee 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1883,8 +1883,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 		 * All pages were isolated from the same lruvec (and isolation
 		 * inhibits memcg migration).
 		 */
-		VM_BUG_ON_PAGE(mem_cgroup_page_lruvec(page, page_pgdat(page))
-							!= lruvec, page);
+		VM_BUG_ON_PAGE(!lruvec_holds_page_lru_lock(page, lruvec), page);
 		lru = page_lru(page);
 		nr_pages = thp_nr_pages(page);
 
@@ -4273,7 +4272,6 @@ void check_move_unevictable_pages(struct pagevec *pvec)
 	for (i = 0; i < pvec->nr; i++) {
 		struct page *page = pvec->pages[i];
 		int nr_pages;
-		struct lruvec *new_lruvec;
 
 		if (PageTransTail(page))
 			continue;
@@ -4285,13 +4283,7 @@ void check_move_unevictable_pages(struct pagevec *pvec)
 		if (!TestClearPageLRU(page))
 			continue;
 
-		new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
-		if (lruvec != new_lruvec) {
-			if (lruvec)
-				unlock_page_lruvec_irq(lruvec);
-			lruvec = lock_page_lruvec_irq(page);
-		}
-
+		lruvec = relock_page_lruvec_irq(page, lruvec);
 		if (page_evictable(page) && PageUnevictable(page)) {
 			enum lru_list lru = page_lru_base_type(page);