[PATCH] call mm/page-writeback.c:set_ratelimit() when new pages are hot-added

ratelimit_pages in page-writeback.c is recalculated (in set_ratelimit())
every time a CPU is hot-added/removed.  But this value is not recalculated
when new pages are hot-added.

This patch fixes that problem by calling set_ratelimit() when new pages
are hot-added.

[akpm@osdl.org: cleanups]
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 efd2705..488b708 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -501,7 +501,7 @@
  * will write six megabyte chunks, max.
  */
 
-static void set_ratelimit(void)
+void writeback_set_ratelimit(void)
 {
 	ratelimit_pages = vm_total_pages / (num_online_cpus() * 32);
 	if (ratelimit_pages < 16)
@@ -513,7 +513,7 @@
 static int __cpuinit
 ratelimit_handler(struct notifier_block *self, unsigned long u, void *v)
 {
-	set_ratelimit();
+	writeback_set_ratelimit();
 	return 0;
 }
 
@@ -546,7 +546,7 @@
 			vm_dirty_ratio = 1;
 	}
 	mod_timer(&wb_timer, jiffies + dirty_writeback_interval);
-	set_ratelimit();
+	writeback_set_ratelimit();
 	register_cpu_notifier(&ratelimit_nb);
 }