[PATCH] ext4: Use sing thread to perform DIO unwritten convertion

[Mingming Cao <cmm@us.ibm.com>]

While running ext4 testing on multiple core, we found there are per cpu ext4-dio-unwritten threads processing
conversion from unwritten extents to written for IOs completed from async direct IO patch.
Per filesystem is enough, we don't need per cpu threads to work on conversion.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
---
 fs/ext4/super.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f6a318f..c76a6a5 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3509,7 +3509,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	percpu_counter_set(&sbi->s_dirtyblocks_counter, 0);
 
 no_journal:
-	EXT4_SB(sb)->dio_unwritten_wq = create_workqueue("ext4-dio-unwritten");
+	EXT4_SB(sb)->dio_unwritten_wq = create_singlethread_workqueue("ext4-dio-unwritten");
 	if (!EXT4_SB(sb)->dio_unwritten_wq) {
 		printk(KERN_ERR "EXT4-fs: failed to create DIO workqueue\n");
 		goto failed_mount_wq;
-- 
1.6.3.3