[PATCH] 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 <sekharan@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 5557529..efd2705 100644 (file)
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -46,7 +46,6 @@
  */
 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 */
 
 /*
@@ -126,7 +125,7 @@ get_dirty_limits(long *pbackground, long *pdirty,
        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
@@ -141,7 +140,7 @@ get_dirty_limits(long *pbackground, long *pdirty,
 
        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)
@@ -504,7 +503,7 @@ 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)
@@ -533,9 +532,7 @@ 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;