mm/page-writeback.c |   33 ++++++++++++++++++++++++---------
 1 files changed, 24 insertions(+), 9 deletions(-)

diff -puN mm/page-writeback.c~throttle-against-free-memory mm/page-writeback.c
--- git-linux/mm/page-writeback.c~throttle-against-free-memory	2005-10-24 13:46:25.000000000 +0400
+++ git-linux-nikita/mm/page-writeback.c	2005-10-24 13:46:25.000000000 +0400
@@ -45,7 +45,6 @@
  */
 static long ratelimit_pages = 32;
 
-static long total_pages;	/* The total number of pages in the machine. */
 static int dirty_exceeded;	/* Dirty mem may be over limit */
 
 /*
@@ -117,6 +116,18 @@ static void get_writeback_state(struct w
 	wbs->nr_async_writeback = read_page_state(nr_async_writeback);
 }
 
+/* Maximal number of pages that can be consumed by pageable caches. */
+static unsigned long total_pageable_pages(void)
+{
+	unsigned long active;
+	unsigned long inactive;
+	unsigned long free;
+
+	get_zone_counts(&active, &inactive, &free);
+	/* +1 to never return 0. */
+	return active + inactive + free + 1;
+}
+
 /*
  * Work out the current dirty-memory clamping and background writeout
  * thresholds.
@@ -143,21 +154,27 @@ get_dirty_limits(struct writeback_state 
 	int unmapped_ratio;
 	long background;
 	long dirty;
-	unsigned long available_memory = total_pages;
+	unsigned long total_pages;
+	unsigned long available_memory;
 	struct task_struct *tsk;
 
 	get_writeback_state(wbs);
 
+	available_memory = total_pages = total_pageable_pages();
+
 #ifdef CONFIG_HIGHMEM
 	/*
 	 * If this mapping can only allocate from low memory,
 	 * we exclude high memory from our count.
 	 */
-	if (mapping && !(mapping_gfp_mask(mapping) & __GFP_HIGHMEM))
-		available_memory -= totalhigh_pages;
+	if (mapping && !(mapping_gfp_mask(mapping) & __GFP_HIGHMEM)) {
+		if (available_memory > totalhigh_pages)
+			available_memory -= totalhigh_pages;
+		else
+			available_memory = 1;
+	}
 #endif
 
-
 	unmapped_ratio = 100 - (wbs->nr_mapped * 100) / total_pages;
 
 	dirty_ratio = vm_dirty_ratio;
@@ -510,7 +527,7 @@ void laptop_sync_completion(void)
 
 static void set_ratelimit(void)
 {
-	ratelimit_pages = total_pages / (num_online_cpus() * 32);
+	ratelimit_pages = total_pageable_pages() / (num_online_cpus() * 32);
 	if (ratelimit_pages < 16)
 		ratelimit_pages = 16;
 	if (ratelimit_pages * PAGE_CACHE_SIZE > 4096 * 1024)
@@ -539,9 +556,7 @@ void __init page_writeback_init(void)
 	long buffer_pages = nr_free_buffer_pages();
 	long correction;
 
-	total_pages = nr_free_pagecache_pages();
-
-	correction = (100 * 4 * buffer_pages) / total_pages;
+	correction = (100 * 4 * buffer_pages) / total_pageable_pages();
 
 	if (correction < 100) {
 		dirty_background_ratio *= correction;

_