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remove static variable mm/page-writeback.c:total_pages

PATCH New Chandra Seetharaman 1 participant 1 message Aug 28, 2006

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Chandra Seetharaman

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PATCH 1/1 remove static variable mm/page-writeback.c:total_pages

page-writeback.c has a static local variable "total_pages", which is the total number of pages in the system.

There is a global variable "vm_total_pages", which is the total number of pages the VM controls.

Both are assigned from the return value of nr_free_pagecache_pages().

This patch removes the local variable and uses the global variable in that place.

One more issue with the local static variable "total_pages" is that it is not updated when new pages are hot-added. Since vm_total_pages is updated when new pages are hot-added, this patch fixes that problem too.

Signed-off-by Chandra Seetharaman <[email protected]>

--

mm/page-writeback.c +4 -7
Index: linux-2.6.17/mm/page-writeback.c
===================================================================
@@ -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 __cacheline_aligned_in_smp;	/* Dirty mem may be over limit */
 
 /*

@@ -125,7 +124,7 @@ get_dirty_limits(long *pbackground, long
 	int unmapped_ratio;
 	long background;
 	long dirty;
-	unsigned long available_memory = total_pages;
+	unsigned long available_memory = vm_total_pages;
 	struct task_struct *tsk;
 
 #ifdef CONFIG_HIGHMEM

@@ -140,7 +139,7 @@ get_dirty_limits(long *pbackground, long
 
 	unmapped_ratio = 100 - ((global_page_state(NR_FILE_MAPPED) +
 				global_page_state(NR_ANON_PAGES)) * 100) /
-					total_pages;
+					vm_total_pages;
 
 	dirty_ratio = vm_dirty_ratio;
 	if (dirty_ratio > unmapped_ratio / 2)

@@ -493,7 +492,7 @@ void laptop_sync_completion(void)
 
 static void set_ratelimit(void)
 {
-	ratelimit_pages = total_pages / (num_online_cpus() * 32);
+	ratelimit_pages = vm_total_pages / (num_online_cpus() * 32);
 	if (ratelimit_pages < 16)
 		ratelimit_pages = 16;
 	if (ratelimit_pages * PAGE_CACHE_SIZE > 4096 * 1024)

@@ -522,9 +521,7 @@ 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) / vm_total_pages;
 
 	if (correction < 100) {
 		dirty_background_ratio *= correction;
Signature · 11 lines
----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - [email protected]   |      .......you may get it.
----------------------------------------------------------------------


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