Btrfs: change the ordered tree to use a spinlock instead of a mutex
The ordered tree used to need a mutex, but currently all we use it for is to
protect the rb_tree, and a spin_lock is just fine for that. Using a spin_lock
instead makes dbench run a little faster, 58 mb/s instead of 51 mb/s, and have
less latency, 3445.138 ms instead of 3820.633 ms.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index 9116c6d..bfbcebb 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -21,7 +21,7 @@
/* one of these per inode */
struct btrfs_ordered_inode_tree {
- struct mutex mutex;
+ spinlock_t lock;
struct rb_root tree;
struct rb_node *last;
};
@@ -128,7 +128,7 @@
static inline void
btrfs_ordered_inode_tree_init(struct btrfs_ordered_inode_tree *t)
{
- mutex_init(&t->mutex);
+ spin_lock_init(&t->lock);
t->tree = RB_ROOT;
t->last = NULL;
}