Index: linux-2.6.15-rc1-mm2/mm/swap_state.c
===================================================================
--- linux-2.6.15-rc1-mm2.orig/mm/swap_state.c	2005-11-21 12:11:07.000000000 -0800
+++ linux-2.6.15-rc1-mm2/mm/swap_state.c	2005-11-21 18:08:38.000000000 -0800
@@ -85,7 +85,7 @@ static int __add_to_swap_cache(struct pa
 			SetPageSwapCache(page);
 			set_page_private(page, entry.val);
 			total_swapcache_pages++;
-			pagecache_acct(1);
+			pagecache_acct(1, page);
 		}
 		write_unlock_irq(&swapper_space.tree_lock);
 		radix_tree_preload_end();
@@ -131,7 +131,7 @@ void __delete_from_swap_cache(struct pag
 	set_page_private(page, 0);
 	ClearPageSwapCache(page);
 	total_swapcache_pages--;
-	pagecache_acct(-1);
+	pagecache_acct(-1, page);
 	INC_CACHE_INFO(del_total);
 }
 
Index: linux-2.6.15-rc1-mm2/include/linux/pagemap.h
===================================================================
--- linux-2.6.15-rc1-mm2.orig/include/linux/pagemap.h	2005-11-21 12:11:07.000000000 -0800
+++ linux-2.6.15-rc1-mm2/include/linux/pagemap.h	2005-11-21 18:41:08.000000000 -0800
@@ -99,49 +99,12 @@ int add_to_page_cache_lru(struct page *p
 extern void remove_from_page_cache(struct page *page);
 extern void __remove_from_page_cache(struct page *page);
 
-extern atomic_t nr_pagecache;
-
-#ifdef CONFIG_SMP
-
-#define PAGECACHE_ACCT_THRESHOLD        max(16, NR_CPUS * 2)
-DECLARE_PER_CPU(long, nr_pagecache_local);
-
 /*
- * pagecache_acct implements approximate accounting for pagecache.
- * vm_enough_memory() do not need high accuracy. Writers will keep
- * an offset in their per-cpu arena and will spill that into the
- * global count whenever the absolute value of the local count
- * exceeds the counter's threshold.
- *
- * MUST be protected from preemption.
- * current protection is mapping->page_lock.
+ * pagecache_acct implements accounting for pagecache.
  */
-static inline void pagecache_acct(int count)
-{
-	long *local;
-
-	local = &__get_cpu_var(nr_pagecache_local);
-	*local += count;
-	if (*local > PAGECACHE_ACCT_THRESHOLD || *local < -PAGECACHE_ACCT_THRESHOLD) {
-		atomic_add(*local, &nr_pagecache);
-		*local = 0;
-	}
-}
-
-#else
-
-static inline void pagecache_acct(int count)
+static inline void pagecache_acct(int count, struct page *page)
 {
-	atomic_add(count, &nr_pagecache);
-}
-#endif
-
-static inline unsigned long get_page_cache_size(void)
-{
-	int ret = atomic_read(&nr_pagecache);
-	if (unlikely(ret < 0))
-		ret = 0;
-	return ret;
+	atomic_add(count, &page_zone(page)->nr_pagecache);
 }
 
 /*
Index: linux-2.6.15-rc1-mm2/mm/filemap.c
===================================================================
--- linux-2.6.15-rc1-mm2.orig/mm/filemap.c	2005-11-21 12:11:07.000000000 -0800
+++ linux-2.6.15-rc1-mm2/mm/filemap.c	2005-11-21 18:06:40.000000000 -0800
@@ -115,7 +115,7 @@ void __remove_from_page_cache(struct pag
 	radix_tree_delete(&mapping->page_tree, page->index);
 	page->mapping = NULL;
 	mapping->nrpages--;
-	pagecache_acct(-1);
+	pagecache_acct(-1, page);
 }
 EXPORT_SYMBOL(__remove_from_page_cache);
 
@@ -406,7 +406,7 @@ int add_to_page_cache(struct page *page,
 			page->mapping = mapping;
 			page->index = offset;
 			mapping->nrpages++;
-			pagecache_acct(1);
+			pagecache_acct(1, page);
 		}
 		write_unlock_irq(&mapping->tree_lock);
 		radix_tree_preload_end();
Index: linux-2.6.15-rc1-mm2/include/linux/mmzone.h
===================================================================
--- linux-2.6.15-rc1-mm2.orig/include/linux/mmzone.h	2005-11-21 14:29:46.000000000 -0800
+++ linux-2.6.15-rc1-mm2/include/linux/mmzone.h	2005-11-21 18:41:59.000000000 -0800
@@ -168,6 +168,8 @@ struct zone {
 	/* A count of how many reclaimers are scanning this zone */
 	atomic_t		reclaim_in_progress;
 
+	/* How many pages are of the page cache */
+	atomic_t		nr_pagecache;
 	/*
 	 * prev_priority holds the scanning priority for this zone.  It is
 	 * defined as the scanning priority at which we achieved our reclaim
@@ -325,9 +327,10 @@ typedef struct pglist_data {
 extern struct pglist_data *pgdat_list;
 
 void __get_zone_counts(unsigned long *active, unsigned long *inactive,
-			unsigned long *free, struct pglist_data *pgdat);
+			unsigned long *free, unsigned long *pagecache,
+			struct pglist_data *pgdat);
 void get_zone_counts(unsigned long *active, unsigned long *inactive,
-			unsigned long *free);
+			unsigned long *free, unsigned long *pagecache);
 void build_all_zonelists(void);
 void wakeup_kswapd(struct zone *zone, int order);
 int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
Index: linux-2.6.15-rc1-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.15-rc1-mm2.orig/mm/page_alloc.c	2005-11-21 13:19:19.000000000 -0800
+++ linux-2.6.15-rc1-mm2/mm/page_alloc.c	2005-11-21 18:47:31.000000000 -0800
@@ -1312,7 +1312,8 @@ void __mod_page_state(unsigned long offs
 EXPORT_SYMBOL(__mod_page_state);
 
 void __get_zone_counts(unsigned long *active, unsigned long *inactive,
-			unsigned long *free, struct pglist_data *pgdat)
+			unsigned long *free, unsigned long *pagecache,
+			struct pglist_data *pgdat)
 {
 	struct zone *zones = pgdat->node_zones;
 	int i;
@@ -1324,23 +1325,27 @@ void __get_zone_counts(unsigned long *ac
 		*active += zones[i].nr_active;
 		*inactive += zones[i].nr_inactive;
 		*free += zones[i].free_pages;
+		*pagecache += atomic_read(&zones[i].nr_pagecache);
 	}
 }
 
 void get_zone_counts(unsigned long *active,
-		unsigned long *inactive, unsigned long *free)
+		unsigned long *inactive, unsigned long *free,
+		unsigned long *pagecache)
 {
 	struct pglist_data *pgdat;
 
 	*active = 0;
 	*inactive = 0;
 	*free = 0;
+	*pagecache = 0;
 	for_each_pgdat(pgdat) {
-		unsigned long l, m, n;
-		__get_zone_counts(&l, &m, &n, pgdat);
+		unsigned long l, m, n, p;
+		__get_zone_counts(&l, &m, &n, &p, pgdat);
 		*active += l;
 		*inactive += m;
 		*free += n;
+		*pagecache += p;
 	}
 }
 
@@ -1389,6 +1394,7 @@ void show_free_areas(void)
 	unsigned long active;
 	unsigned long inactive;
 	unsigned long free;
+	unsigned long nr_pagecache;
 	struct zone *zone;
 
 	for_each_zone(zone) {
@@ -1418,20 +1424,21 @@ void show_free_areas(void)
 	}
 
 	get_page_state(&ps);
-	get_zone_counts(&active, &inactive, &free);
+	get_zone_counts(&active, &inactive, &free, &nr_pagecache);
 
 	printk("Free pages: %11ukB (%ukB HighMem)\n",
 		K(nr_free_pages()),
 		K(nr_free_highpages()));
 
 	printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu "
-		"unstable:%lu free:%u slab:%lu mapped:%lu pagetables:%lu\n",
+		"unstable:%lu free:%u pagecache:%lu slab:%lu mapped:%lu pagetables:%lu\n",
 		active,
 		inactive,
 		ps.nr_dirty,
 		ps.nr_writeback,
 		ps.nr_unstable,
 		nr_free_pages(),
+		nr_pagecache,
 		ps.nr_slab,
 		ps.nr_mapped,
 		ps.nr_page_table_pages);
Index: linux-2.6.15-rc1-mm2/fs/proc/proc_misc.c
===================================================================
--- linux-2.6.15-rc1-mm2.orig/fs/proc/proc_misc.c	2005-11-21 12:11:07.000000000 -0800
+++ linux-2.6.15-rc1-mm2/fs/proc/proc_misc.c	2005-11-21 18:20:07.000000000 -0800
@@ -124,13 +124,14 @@ static int meminfo_read_proc(char *page,
 	unsigned long inactive;
 	unsigned long active;
 	unsigned long free;
+	unsigned long pagecache;
 	unsigned long committed;
 	unsigned long allowed;
 	struct vmalloc_info vmi;
 	long cached;
 
 	get_page_state(&ps);
-	get_zone_counts(&active, &inactive, &free);
+	get_zone_counts(&active, &inactive, &free, &pagecache);
 
 /*
  * display in kilobytes.
@@ -142,7 +143,7 @@ static int meminfo_read_proc(char *page,
 	allowed = ((totalram_pages - hugetlb_total_pages())
 		* sysctl_overcommit_ratio / 100) + total_swap_pages;
 
-	cached = get_page_cache_size() - total_swapcache_pages - i.bufferram;
+	cached = pagecache - total_swapcache_pages - i.bufferram;
 	if (cached < 0)
 		cached = 0;
 
Index: linux-2.6.15-rc1-mm2/mm/mmap.c
===================================================================
--- linux-2.6.15-rc1-mm2.orig/mm/mmap.c	2005-11-21 12:11:07.000000000 -0800
+++ linux-2.6.15-rc1-mm2/mm/mmap.c	2005-11-21 18:29:23.000000000 -0800
@@ -93,9 +93,14 @@ int __vm_enough_memory(long pages, int c
 		return 0;
 
 	if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
-		unsigned long n;
+		unsigned long n, pfree, pagecache;
 
-		free = get_page_cache_size();
+		get_zone_counts(&n, &n, &pfree, &pagecache);
+
+		if (!cap_sys_admin)
+			pfree -= pfree / 32;
+
+		free = pagecache + pfree;
 		free += nr_swap_pages;
 
 		/*
@@ -115,17 +120,6 @@ int __vm_enough_memory(long pages, int c
 		if (free > pages)
 			return 0;
 
-		/*
-		 * nr_free_pages() is very expensive on large systems,
-		 * only call if we're about to fail.
-		 */
-		n = nr_free_pages();
-		if (!cap_sys_admin)
-			n -= n / 32;
-		free += n;
-
-		if (free > pages)
-			return 0;
 		vm_unacct_memory(pages);
 		return -ENOMEM;
 	}
Index: linux-2.6.15-rc1-mm2/drivers/base/node.c
===================================================================
--- linux-2.6.15-rc1-mm2.orig/drivers/base/node.c	2005-11-11 17:43:36.000000000 -0800
+++ linux-2.6.15-rc1-mm2/drivers/base/node.c	2005-11-21 18:49:43.000000000 -0800
@@ -43,10 +43,11 @@ static ssize_t node_read_meminfo(struct 
 	unsigned long inactive;
 	unsigned long active;
 	unsigned long free;
+	unsigned long pagecache;
 
 	si_meminfo_node(&i, nid);
 	get_page_state_node(&ps, nid);
-	__get_zone_counts(&active, &inactive, &free, NODE_DATA(nid));
+	__get_zone_counts(&active, &inactive, &free, &pagecache, NODE_DATA(nid));
 
 	/* Check for negative values in these approximate counters */
 	if ((long)ps.nr_dirty < 0)
@@ -71,6 +72,7 @@ static ssize_t node_read_meminfo(struct 
 		       "Node %d Dirty:        %8lu kB\n"
 		       "Node %d Writeback:    %8lu kB\n"
 		       "Node %d Mapped:       %8lu kB\n"
+		       "Node %d Pagecache:    %8lu KB\n"
 		       "Node %d Slab:         %8lu kB\n",
 		       nid, K(i.totalram),
 		       nid, K(i.freeram),
@@ -83,6 +85,7 @@ static ssize_t node_read_meminfo(struct 
 		       nid, K(i.freeram - i.freehigh),
 		       nid, K(ps.nr_dirty),
 		       nid, K(ps.nr_writeback),
+		       nid, K(pagecache),
 		       nid, K(ps.nr_mapped),
 		       nid, K(ps.nr_slab));
 	n += hugetlb_report_node_meminfo(nid, buf + n);
Index: linux-2.6.15-rc1-mm2/mm/readahead.c
===================================================================
--- linux-2.6.15-rc1-mm2.orig/mm/readahead.c	2005-11-21 12:11:07.000000000 -0800
+++ linux-2.6.15-rc1-mm2/mm/readahead.c	2005-11-21 18:48:25.000000000 -0800
@@ -571,7 +571,8 @@ unsigned long max_sane_readahead(unsigne
 	unsigned long active;
 	unsigned long inactive;
 	unsigned long free;
+	unsigned long pagecache;
 
-	__get_zone_counts(&active, &inactive, &free, NODE_DATA(numa_node_id()));
+	__get_zone_counts(&active, &inactive, &free, &pagecache, NODE_DATA(numa_node_id()));
 	return min(nr, (inactive + free) / 2);
 }