2 files changed, 38 insertions, 32 deletions

diff --git a/mm/swap.c b/mm/swap.c
index b524ea90bddb..3045a0f4c451 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -209,19 +209,18 @@ int lru_add_drain_all(void)
  */
 void fastcall __page_cache_release(struct page *page)
 {
-        unsigned long flags;
-        struct zone *zone = page_zone(page);
+        if (PageLRU(page)) {
+                unsigned long flags;
+                struct zone *zone = page_zone(page);
 
-        spin_lock_irqsave(&zone->lru_lock, flags);
-        if (TestClearPageLRU(page))
+                spin_lock_irqsave(&zone->lru_lock, flags);
+                if (!TestClearPageLRU(page))
+                        BUG();
                 del_page_from_lru(zone, page);
-        if (page_count(page) != 0)
-                page = NULL;
-        spin_unlock_irqrestore(&zone->lru_lock, flags);
-        if (page)
-                free_hot_page(page);
+                spin_unlock_irqrestore(&zone->lru_lock, flags);
+        }
+        free_hot_page(page);
 }
-
 EXPORT_SYMBOL(__page_cache_release);
 
 /*
@@ -245,7 +244,6 @@ void release_pages(struct page **pages, int nr, int cold)
         pagevec_init(&pages_to_free, cold);
         for (i = 0; i < nr; i++) {
                 struct page *page = pages[i];
-                struct zone *pagezone;
 
                 if (unlikely(PageCompound(page))) {
                         if (zone) {
@@ -259,23 +257,27 @@ void release_pages(struct page **pages, int nr, int cold)
                 if (!put_page_testzero(page))
                         continue;
 
-                pagezone = page_zone(page);
-                if (pagezone != zone) {
-                        if (zone)
-                                spin_unlock_irq(&zone->lru_lock);
-                        zone = pagezone;
-                        spin_lock_irq(&zone->lru_lock);
-                }
-                if (TestClearPageLRU(page))
+                if (PageLRU(page)) {
+                        struct zone *pagezone = page_zone(page);
+                        if (pagezone != zone) {
+                                if (zone)
+                                        spin_unlock_irq(&zone->lru_lock);
+                                zone = pagezone;
+                                spin_lock_irq(&zone->lru_lock);
+                        }
+                        if (!TestClearPageLRU(page))
+                                BUG();
                         del_page_from_lru(zone, page);
-                if (page_count(page) == 0) {
-                        if (!pagevec_add(&pages_to_free, page)) {
+                }
+
+                if (!pagevec_add(&pages_to_free, page)) {
+                        if (zone) {
                                 spin_unlock_irq(&zone->lru_lock);
-                                __pagevec_free(&pages_to_free);
-                                pagevec_reinit(&pages_to_free);
-                                zone = NULL;    /* No lock is held */
+                                zone = NULL;
                         }
-                }
+                        __pagevec_free(&pages_to_free);
+                        pagevec_reinit(&pages_to_free);
+                }
         }
         if (zone)
                 spin_unlock_irq(&zone->lru_lock);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 4fe7e3aa02e2..acb7611cd525 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1085,21 +1085,25 @@ static int isolate_lru_pages(int nr_to_scan, struct list_head *src,
                 page = lru_to_page(src);
                 prefetchw_prev_lru_page(page, src, flags);
 
-                if (!TestClearPageLRU(page))
-                        BUG();
                 list_del(&page->lru);
-                if (get_page_testone(page)) {
+                if (unlikely(get_page_testone(page))) {
                         /*
                          * It is being freed elsewhere
                          */
                         __put_page(page);
-                        SetPageLRU(page);
                         list_add(&page->lru, src);
                         continue;
-                } else {
-                        list_add(&page->lru, dst);
-                        nr_taken++;
                 }
+
+                /*
+                 * Be careful not to clear PageLRU until after we're sure
+                 * the page is not being freed elsewhere -- the page release
+                 * code relies on it.
+                 */
+                if (!TestClearPageLRU(page))
+                        BUG();
+                list_add(&page->lru, dst);
+                nr_taken++;
         }
 
         *scanned = scan;