Index: linux-2.6.20/mm/migrate.c
===================================================================
--- linux-2.6.20.orig/mm/migrate.c	2007-02-14 16:54:39.000000000 -0800
+++ linux-2.6.20/mm/migrate.c	2007-02-14 16:54:45.000000000 -0800
@@ -64,7 +64,7 @@
 			get_page(page);
 			ClearPageMlocked(page);
 			list_add_tail(&page->lru, pagelist);
-			__dec_zone_page_state(zone, NR_MLOCK);
+			__dec_zone_state(zone, NR_MLOCK);
 		}
 		spin_unlock_irq(&zone->lru_lock);
 	}
Index: linux-2.6.20/mm/swap.c
===================================================================
--- linux-2.6.20.orig/mm/swap.c	2007-02-14 16:58:29.000000000 -0800
+++ linux-2.6.20/mm/swap.c	2007-02-14 17:04:32.000000000 -0800
@@ -408,8 +408,8 @@
 		VM_BUG_ON(PageLRU(page));
 		SetPageLRU(page);
 		VM_BUG_ON(PageActive(page));
-		VM_BUG_ON(PageMlocked(page));
 		SetPageActive(page);
+		VM_BUG_ON(PageMlocked(page));
 		add_page_to_active_list(zone, page);
 	}
 	if (zone)
@@ -434,13 +434,13 @@
 			spin_lock_irq(&zone->lru_lock);
 		}
 		if (!PageMlocked(page))
+			/* Another process already moved page to LRU */
 			continue;
 		BUG_ON(PageLRU(page));
-		ClearPageMlocked(page);
-		smp_wmb();
-		__dec_zone_state(zone, NR_MLOCK);
 		SetPageLRU(page);
+		ClearPageMlocked(page);
 		SetPageActive(page);
+		__dec_zone_state(zone, NR_MLOCK);
 		add_page_to_active_list(zone, page);
 	}
 	if (zone)