commit 36715cef0770b7e2547892b7c3197fc024274630
author Wu Fengguang <fengguang.wu@intel.com> Sat Jun 11 17:53:57 2011 -0600
committer Wu Fengguang <fengguang.wu@intel.com> Mon Jun 20 00:25:46 2011 +0800
tree 34b690df719e6e46a37e0cef40b8c21f34bc36f8
parent e84d0a4f8e39a73003a6ec9a11b07702745f4c1f

writeback: skip tmpfs early in balance_dirty_pages_ratelimited_nr()

This helps prevent tmpfs dirtiers from skewing the per-cpu bdp_ratelimits.

Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>

mm/page-writeback.c

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index b2529f8..1965d05 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -490,9 +490,6 @@
 	bool dirty_exceeded = false;
 	struct backing_dev_info *bdi = mapping->backing_dev_info;
 
-	if (!bdi_cap_account_dirty(bdi))
-		return;
-
 	for (;;) {
 		struct writeback_control wbc = {
 			.sync_mode	= WB_SYNC_NONE,
@@ -631,9 +628,13 @@
 void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
 					unsigned long nr_pages_dirtied)
 {
+	struct backing_dev_info *bdi = mapping->backing_dev_info;
 	unsigned long ratelimit;
 	unsigned long *p;
 
+	if (!bdi_cap_account_dirty(bdi))
+		return;
+
 	ratelimit = ratelimit_pages;
 	if (mapping->backing_dev_info->dirty_exceeded)
 		ratelimit = 8;