Index: linux-2.6.16-rc1-mm4/Makefile
===================================================================
--- linux-2.6.16-rc1-mm4.orig/Makefile	2006-01-30 11:27:37.000000000 -0800
+++ linux-2.6.16-rc1-mm4/Makefile	2006-01-31 11:12:48.000000000 -0800
@@ -1,7 +1,7 @@
 VERSION = 2
 PATCHLEVEL = 6
 SUBLEVEL = 16
-EXTRAVERSION =-rc1-mm4
+EXTRAVERSION =-rc1-mm4-debug
 NAME=Sliding Snow Leopard
 
 # *DOCUMENTATION*
Index: linux-2.6.16-rc1-mm4/mm/page_alloc.c
===================================================================
--- linux-2.6.16-rc1-mm4.orig/mm/page_alloc.c	2006-01-31 11:12:31.000000000 -0800
+++ linux-2.6.16-rc1-mm4/mm/page_alloc.c	2006-01-31 17:17:06.000000000 -0800
@@ -377,6 +377,7 @@ static void __free_one_page(struct page 
 			zone->zeroed_pages -= 1 << order;
 			__ClearPageZeroed(page);
 			__ClearPageZeroed(buddy);
+			add_page_state(zeroed_merge_waste, 1 << order);
 		}
 		list_del(&buddy->lru);
 		area = zone->free_area + order;
@@ -384,14 +385,15 @@ static void __free_one_page(struct page 
 		rmv_page_order(buddy);
 		combined_idx = __find_combined_index(page_idx, order);
 		page = page + (combined_idx - page_idx);
-		if (both_zeroed)
+		if (both_zeroed) {
 			/*
 			 * The first page's status determines the zero status
 			 * of the combined page. We know that that is set.
 			 * However, the zero bit of the second half must
 			 * be cleared
 			 */
-			__SetPageZeroed(page + (1 << order));
+			__ClearPageZeroed(page + (1 << order));
+		}
 		page_idx = combined_idx;
 		order++;
 	}
@@ -875,6 +877,20 @@ static inline void prep_zero_page(struct
 		clear_highpage(page + i);
 }
 
+static inline void verify_zero_page(struct page *page, int order, gfp_t gfp_flags)
+{
+	int i;
+
+	unsigned char *a = page_address(page);
+
+	for (i = 0; i < (PAGE_SIZE << order); i++)
+		if (a[i]) {
+			printk(KERN_ERR "Page %p not zeroed. Order %d Byte offset %d\n",
+						page, order, i);
+			prep_zero_page(page, order, gfp_flags);
+		}
+}
+
 #ifdef CONFIG_MMU
 /*
  * split_page takes a non-compound higher-order page, and splits it into
@@ -948,8 +964,15 @@ again:
 
 	BUG_ON(bad_range(zone, page));
 
-	if (gfp_flags & __GFP_ZERO && !PageZeroed(page))
+	if (gfp_flags & __GFP_ZERO) {
+	if (!PageZeroed(page)) {
 		prep_zero_page(page, order, gfp_flags);
+		add_page_state(zeroed_sync, 1 << order);
+	} else {
+		add_page_state(zero_avoid, 1 << order);
+		verify_zero_page(page, order, gfp_flags);
+	}
+	}
 
 	if (prep_new_page(page, order))
 		goto again;
@@ -2225,6 +2248,7 @@ static void scrub_pgdat(pg_data_t *pgdat
 				__SetPageZeroed(page);
 				zone->zeroed_pages += 1 << order;
 				__free_one_page(page, zone, order);
+				add_page_state(zeroed_scrubd, 1 << order);
 			}
 		}
 	}
@@ -2661,6 +2685,10 @@ static char *vmstat_text[] = {
 
 	"pgrotated",
 	"nr_bounce",
+
+	"zeroed_scrubd",
+	"zeroed_sync",
+	"zero_avoided",
 };
 
 static void *vmstat_start(struct seq_file *m, loff_t *pos)
Index: linux-2.6.16-rc1-mm4/include/linux/page-flags.h
===================================================================
--- linux-2.6.16-rc1-mm4.orig/include/linux/page-flags.h	2006-01-30 17:23:11.000000000 -0800
+++ linux-2.6.16-rc1-mm4/include/linux/page-flags.h	2006-01-31 11:12:48.000000000 -0800
@@ -152,6 +152,10 @@ struct page_state {
 
 	unsigned long pgrotated;	/* pages rotated to tail of the LRU */
 	unsigned long nr_bounce;	/* pages for bounce buffers */
+
+	unsigned long zeroed_scrubd;	/* zeroed by scrubd */
+	unsigned long zeroed_sync;	/* synchrononous zeroing */
+	unsigned long zero_avoid;	/* avoided zeroing */
 };
 
 extern void get_page_state(struct page_state *ret);