mm/swap.c: export activate_page()

activate_page() is needed to activate pages that are already on lru or
queued in lru_pvecs.lru_add. The exported function is a merger between
the existing activate_page() and __lru_cache_activate_page().

Signed-off-by: Yu Zhao <yuzhao@google.com>

include/linux/swap.h

@@ -344,6 +344,7 @@ extern void lru_add_drain_cpu(int cpu);
 extern void lru_add_drain_cpu_zone(struct zone *zone);
 extern void lru_add_drain_all(void);
 extern void rotate_reclaimable_page(struct page *page);
+extern void activate_page(struct page *page);
 extern void deactivate_file_page(struct page *page);
 extern void deactivate_page(struct page *page);
 extern void mark_page_lazyfree(struct page *page);

mm/swap.c

@@ -334,7 +334,7 @@ static bool need_activate_page_drain(int cpu)
 	return pagevec_count(&per_cpu(lru_pvecs.activate_page, cpu)) != 0;
 }
 
-static void activate_page(struct page *page)
+static void activate_page_on_lru(struct page *page)
 {
 	page = compound_head(page);
 	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
@@ -354,7 +354,7 @@ static inline void activate_page_drain(int cpu)
 {
 }
 
-static void activate_page(struct page *page)
+static void activate_page_on_lru(struct page *page)
 {
 	struct lruvec *lruvec;
 
@@ -368,11 +368,22 @@ static void activate_page(struct page *page)
 }
 #endif
 
-static void __lru_cache_activate_page(struct page *page)
+/*
+ * If the page is on the LRU, queue it for activation via
+ * lru_pvecs.activate_page. Otherwise, assume the page is on a
+ * pagevec, mark it active and it'll be moved to the active
+ * LRU on the next drain.
+ */
+void activate_page(struct page *page)
 {
 	struct pagevec *pvec;
 	int i;
 
+	if (PageLRU(page)) {
+		activate_page_on_lru(page);
+		return;
+	}
+
 	local_lock(&lru_pvecs.lock);
 	pvec = this_cpu_ptr(&lru_pvecs.lru_add);
 
@@ -421,16 +432,7 @@ void mark_page_accessed(struct page *page)
 		 * evictable page accessed has no effect.
 		 */
 	} else if (!PageActive(page)) {
-		/*
-		 * If the page is on the LRU, queue it for activation via
-		 * lru_pvecs.activate_page. Otherwise, assume the page is on a
-		 * pagevec, mark it active and it'll be moved to the active
-		 * LRU on the next drain.
-		 */
-		if (PageLRU(page))
-			activate_page(page);
-		else
-			__lru_cache_activate_page(page);
+		activate_page(page);
 		ClearPageReferenced(page);
 		workingset_activation(page);
 	}