writeback: Do not sort b_io list only because of block device inode
It is very likely that block device inode will be part of BDI dirty list
as well. However it doesn't make sence to sort inodes on the b_io list
just because of this inode (as it contains buffers all over the device
anyway). So save some CPU cycles which is valuable since we hold relatively
contented wb->list_lock.
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 3be5718..cabdece 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -68,7 +68,7 @@
{
struct super_block *sb = inode->i_sb;
- if (strcmp(sb->s_type->name, "bdev") == 0)
+ if (sb_is_blkdev_sb(sb))
return inode->i_mapping->backing_dev_info;
return sb->s_bdi;
@@ -250,11 +250,13 @@
if (work->older_than_this &&
inode_dirtied_after(inode, *work->older_than_this))
break;
+ list_move(&inode->i_wb_list, &tmp);
+ moved++;
+ if (sb_is_blkdev_sb(inode->i_sb))
+ continue;
if (sb && sb != inode->i_sb)
do_sb_sort = 1;
sb = inode->i_sb;
- list_move(&inode->i_wb_list, &tmp);
- moved++;
}
/* just one sb in list, splice to dispatch_queue and we're done */