Index: linux-2.6.15-rc2/include/linux/rmap.h
===================================================================
--- linux-2.6.15-rc2.orig/include/linux/rmap.h	2005-11-23 02:16:00.000000000 +0000
+++ linux-2.6.15-rc2/include/linux/rmap.h	2005-11-23 02:17:25.000000000 +0000
@@ -72,7 +72,7 @@ void __anon_vma_link(struct vm_area_stru
  */
 void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
 void page_add_file_rmap(struct page *);
-void page_remove_rmap(struct page *);
+int page_remove_rmap(struct page *);
 
 /**
  * page_dup_rmap - duplicate pte mapping to a page
Index: linux-2.6.15-rc2/mm/rmap.c
===================================================================
--- linux-2.6.15-rc2.orig/mm/rmap.c	2005-11-23 02:16:00.000000000 +0000
+++ linux-2.6.15-rc2/mm/rmap.c	2005-11-23 02:45:16.000000000 +0000
@@ -484,8 +484,10 @@ void page_add_file_rmap(struct page *pag
  * @page: page to remove mapping from
  *
  * The caller needs to hold the pte lock.
+ *
+ * Return 1 if the page_zone(page)->nr_unmapped needs to be incremented.
  */
-void page_remove_rmap(struct page *page)
+int page_remove_rmap(struct page *page)
 {
 	if (atomic_add_negative(-1, &page->_mapcount)) {
 		BUG_ON(page_mapcount(page) < 0);
@@ -501,7 +503,9 @@ void page_remove_rmap(struct page *page)
 		if (page_test_and_clear_dirty(page))
 			set_page_dirty(page);
 		dec_page_state(nr_mapped);
+		return 1;
 	}
+	return 0;
 }
 
 /*
@@ -569,7 +573,9 @@ static int try_to_unmap_one(struct page 
 	} else
 		dec_mm_counter(mm, file_rss);
 
-	page_remove_rmap(page);
+	if (page_remove_rmap(page))
+		ret = SWAP_SUCCESS;
+
 	page_cache_release(page);
 
 out_unmap:
@@ -687,7 +693,7 @@ static int try_to_unmap_anon(struct page
 
 	list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
 		ret = try_to_unmap_one(page, vma);
-		if (ret == SWAP_FAIL || !page_mapped(page))
+		if (ret == SWAP_FAIL || ret == SWAP_SUCCESS)
 			break;
 	}
 	spin_unlock(&anon_vma->lock);
@@ -718,7 +724,7 @@ static int try_to_unmap_file(struct page
 	spin_lock(&mapping->i_mmap_lock);
 	vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
 		ret = try_to_unmap_one(page, vma);
-		if (ret == SWAP_FAIL || !page_mapped(page))
+		if (ret == SWAP_FAIL)
 			goto out;
 	}
 
@@ -750,8 +756,10 @@ static int try_to_unmap_file(struct page
 	 * but even so use it as a guide to how hard we should try?
 	 */
 	mapcount = page_mapcount(page);
-	if (!mapcount)
+	if (!mapcount) {
+		ret = SWAP_AGAIN;
 		goto out;
+	}
 	cond_resched_lock(&mapping->i_mmap_lock);
 
 	max_nl_size = (max_nl_size + CLUSTER_SIZE - 1) & CLUSTER_MASK;
@@ -816,8 +824,6 @@ int try_to_unmap(struct page *page)
 	else
 		ret = try_to_unmap_file(page);
 
-	if (!page_mapped(page))
-		ret = SWAP_SUCCESS;
 	return ret;
 }
 
Index: linux-2.6.15-rc2/mm/vmscan.c
===================================================================
--- linux-2.6.15-rc2.orig/mm/vmscan.c	2005-11-23 02:12:59.000000000 +0000
+++ linux-2.6.15-rc2/mm/vmscan.c	2005-11-23 02:28:23.000000000 +0000
@@ -61,7 +61,7 @@ struct scan_control {
 	/* Incremented by the number of pages reclaimed */
 	unsigned long nr_reclaimed;
 
-	unsigned long nr_mapped;	/* From page_state */
+	unsigned long nr_unmapped;	/* From page_state */
 
 	/* How many pages shrink_cache() should reclaim */
 	int nr_to_reclaim;
@@ -379,6 +379,7 @@ static int shrink_list(struct list_head 
 	struct pagevec freed_pvec;
 	int pgactivate = 0;
 	int reclaimed = 0;
+	int unmapped = 0;
 
 	cond_resched();
 
@@ -440,7 +441,7 @@ static int shrink_list(struct list_head 
 			case SWAP_AGAIN:
 				goto keep_locked;
 			case SWAP_SUCCESS:
-				; /* try to free the page below */
+				unmapped++; /* try to free the page below */
 			}
 		}
 
@@ -559,6 +560,7 @@ keep:
 		__pagevec_release_nonlru(&freed_pvec);
 	mod_page_state(pgactivate, pgactivate);
 	sc->nr_reclaimed += reclaimed;
+	sc->nr_unmapped += unmapped;
 	return reclaimed;
 }
 
@@ -645,11 +647,14 @@ static void shrink_cache(struct zone *zo
 			mod_page_state_zone(zone, pgscan_kswapd, nr_scan);
 		else
 			mod_page_state_zone(zone, pgscan_direct, nr_scan);
+		sc->nr_unmapped = 0;
+
 		nr_freed = shrink_list(&page_list, sc);
 		if (current_is_kswapd())
 			mod_page_state(kswapd_steal, nr_freed);
 		mod_page_state_zone(zone, pgsteal, nr_freed);
 		sc->nr_to_reclaim -= nr_freed;
+		zone->nr_unmapped += sc->unmapped - nr_freed;
 
 		spin_lock_irq(&zone->lru_lock);
 		/*
@@ -1358,6 +1363,7 @@ int zone_reclaim(struct zone *zone, gfp_
 	sc.nr_mapped = read_page_state(nr_mapped);
 	sc.nr_scanned = 0;
 	sc.nr_reclaimed = 0;
+	sc.nr_unmapped = 0;
 	/* scan at the highest priority */
 	sc.priority = 0;
 
Index: linux-2.6.15-rc2/mm/memory.c
===================================================================
--- linux-2.6.15-rc2.orig/mm/memory.c	2005-11-23 02:12:59.000000000 +0000
+++ linux-2.6.15-rc2/mm/memory.c	2005-11-23 02:38:55.000000000 +0000
@@ -618,6 +618,8 @@ static unsigned long zap_pte_range(struc
 			}
 			page_remove_rmap(page);
 			tlb_remove_page(tlb, page);
+			if (!page_mapcount(page))
+				page_zone(page)->nr_unmapped++;
 			continue;
 		}
 		/*