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.c b/fs/btrfs/ordered-data.c
index 5c2a9e7..d56f732 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -174,7 +174,6 @@
if (!entry)
return -ENOMEM;
- mutex_lock(&tree->mutex);
entry->file_offset = file_offset;
entry->start = start;
entry->len = len;
@@ -190,16 +189,17 @@
INIT_LIST_HEAD(&entry->list);
INIT_LIST_HEAD(&entry->root_extent_list);
+ spin_lock(&tree->lock);
node = tree_insert(&tree->tree, file_offset,
&entry->rb_node);
BUG_ON(node);
+ spin_unlock(&tree->lock);
spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
list_add_tail(&entry->root_extent_list,
&BTRFS_I(inode)->root->fs_info->ordered_extents);
spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
- mutex_unlock(&tree->mutex);
BUG_ON(node);
return 0;
}
@@ -216,9 +216,9 @@
struct btrfs_ordered_inode_tree *tree;
tree = &BTRFS_I(inode)->ordered_tree;
- mutex_lock(&tree->mutex);
+ spin_lock(&tree->lock);
list_add_tail(&sum->list, &entry->list);
- mutex_unlock(&tree->mutex);
+ spin_unlock(&tree->lock);
return 0;
}
@@ -240,7 +240,7 @@
int ret;
tree = &BTRFS_I(inode)->ordered_tree;
- mutex_lock(&tree->mutex);
+ spin_lock(&tree->lock);
node = tree_search(tree, file_offset);
if (!node) {
ret = 1;
@@ -264,7 +264,7 @@
else
ret = 1;
out:
- mutex_unlock(&tree->mutex);
+ spin_unlock(&tree->lock);
return ret == 0;
}
@@ -291,7 +291,7 @@
/*
* remove an ordered extent from the tree. No references are dropped
- * and you must wake_up entry->wait. You must hold the tree mutex
+ * and you must wake_up entry->wait. You must hold the tree lock
* while you call this function.
*/
static int __btrfs_remove_ordered_extent(struct inode *inode,
@@ -340,9 +340,9 @@
int ret;
tree = &BTRFS_I(inode)->ordered_tree;
- mutex_lock(&tree->mutex);
+ spin_lock(&tree->lock);
ret = __btrfs_remove_ordered_extent(inode, entry);
- mutex_unlock(&tree->mutex);
+ spin_unlock(&tree->lock);
wake_up(&entry->wait);
return ret;
@@ -567,7 +567,7 @@
struct btrfs_ordered_extent *entry = NULL;
tree = &BTRFS_I(inode)->ordered_tree;
- mutex_lock(&tree->mutex);
+ spin_lock(&tree->lock);
node = tree_search(tree, file_offset);
if (!node)
goto out;
@@ -578,7 +578,7 @@
if (entry)
atomic_inc(&entry->refs);
out:
- mutex_unlock(&tree->mutex);
+ spin_unlock(&tree->lock);
return entry;
}
@@ -594,7 +594,7 @@
struct btrfs_ordered_extent *entry = NULL;
tree = &BTRFS_I(inode)->ordered_tree;
- mutex_lock(&tree->mutex);
+ spin_lock(&tree->lock);
node = tree_search(tree, file_offset);
if (!node)
goto out;
@@ -602,7 +602,7 @@
entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
atomic_inc(&entry->refs);
out:
- mutex_unlock(&tree->mutex);
+ spin_unlock(&tree->lock);
return entry;
}
@@ -629,7 +629,7 @@
else
offset = ALIGN(offset, BTRFS_I(inode)->root->sectorsize);
- mutex_lock(&tree->mutex);
+ spin_lock(&tree->lock);
disk_i_size = BTRFS_I(inode)->disk_i_size;
/* truncate file */
@@ -735,7 +735,7 @@
*/
if (ordered)
__btrfs_remove_ordered_extent(inode, ordered);
- mutex_unlock(&tree->mutex);
+ spin_unlock(&tree->lock);
if (ordered)
wake_up(&ordered->wait);
return ret;
@@ -762,7 +762,7 @@
if (!ordered)
return 1;
- mutex_lock(&tree->mutex);
+ spin_lock(&tree->lock);
list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
if (disk_bytenr >= ordered_sum->bytenr) {
num_sectors = ordered_sum->len / sectorsize;
@@ -777,7 +777,7 @@
}
}
out:
- mutex_unlock(&tree->mutex);
+ spin_unlock(&tree->lock);
btrfs_put_ordered_extent(ordered);
return ret;
}