Btrfs: use a slab for ordered extents allocation
The ordered extent allocation is in the fast path of the IO, so use a slab
to improve the speed of the allocation.
"Size of the struct is 280, so this will fall into the size-512 bucket,
giving 8 objects per page, while own slab will pack 14 objects into a page.
Another benefit I see is to check for leaked objects when the module is
removed (and the cache destroy takes place)."
-- David Sterba
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index c2443a4..d1ddaef 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -192,4 +192,6 @@
struct inode *inode);
void btrfs_wait_ordered_extents(struct btrfs_root *root,
int nocow_only, int delay_iput);
+int __init ordered_data_init(void);
+void ordered_data_exit(void);
#endif