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Commit 49958fd7 authored by Josef Bacik's avatar Josef Bacik Committed by Chris Mason
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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: default avatarJosef Bacik <josef@redhat.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 4125bf76

fs/btrfs/ordered-data.c

+17 −17
Original line number Original line Diff line number Diff line
@@ -174,7 +174,6 @@ int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset, 
	if (!entry)

	if (!entry)

		return -ENOMEM;

		return -ENOMEM;





	mutex_lock(&tree->mutex);

	entry->file_offset = file_offset;

	entry->file_offset = file_offset;

	entry->start = start;

	entry->start = start;

	entry->len = len;

	entry->len = len;
@@ -190,16 +189,17 @@ int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset, 
	INIT_LIST_HEAD(&entry->list);

	INIT_LIST_HEAD(&entry->list);

	INIT_LIST_HEAD(&entry->root_extent_list);

	INIT_LIST_HEAD(&entry->root_extent_list);





	spin_lock(&tree->lock);

	node = tree_insert(&tree->tree, file_offset,

	node = tree_insert(&tree->tree, file_offset,

			   &entry->rb_node);

			   &entry->rb_node);

	BUG_ON(node);

	BUG_ON(node);

	spin_unlock(&tree->lock);





	spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);

	spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);

	list_add_tail(&entry->root_extent_list,

	list_add_tail(&entry->root_extent_list,

		      &BTRFS_I(inode)->root->fs_info->ordered_extents);

		      &BTRFS_I(inode)->root->fs_info->ordered_extents);

	spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);

	spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);





	mutex_unlock(&tree->mutex);

	BUG_ON(node);

	BUG_ON(node);

	return 0;

	return 0;

}

}
@@ -216,9 +216,9 @@ int btrfs_add_ordered_sum(struct inode *inode, 
	struct btrfs_ordered_inode_tree *tree;

	struct btrfs_ordered_inode_tree *tree;





	tree = &BTRFS_I(inode)->ordered_tree;

	tree = &BTRFS_I(inode)->ordered_tree;

	mutex_lock(&tree->mutex);

	spin_lock(&tree->lock);

	list_add_tail(&sum->list, &entry->list);

	list_add_tail(&sum->list, &entry->list);

	mutex_unlock(&tree->mutex);

	spin_unlock(&tree->lock);

	return 0;

	return 0;

}

}
@@ -240,7 +240,7 @@ int btrfs_dec_test_ordered_pending(struct inode *inode, 
	int ret;

	int ret;





	tree = &BTRFS_I(inode)->ordered_tree;

	tree = &BTRFS_I(inode)->ordered_tree;

	mutex_lock(&tree->mutex);

	spin_lock(&tree->lock);

	node = tree_search(tree, file_offset);

	node = tree_search(tree, file_offset);

	if (!node) {

	if (!node) {

		ret = 1;

		ret = 1;
@@ -264,7 +264,7 @@ int btrfs_dec_test_ordered_pending(struct inode *inode, 
	else

	else

		ret = 1;

		ret = 1;

out:

out:

	mutex_unlock(&tree->mutex);

	spin_unlock(&tree->lock);

	return ret == 0;

	return ret == 0;

}

}
@@ -291,7 +291,7 @@ int btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry) 




/*

/*

 * remove an ordered extent from the tree.  No references are dropped

 * 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.

 * while you call this function.

 */

 */

static int __btrfs_remove_ordered_extent(struct inode *inode,

static int __btrfs_remove_ordered_extent(struct inode *inode,
@@ -340,9 +340,9 @@ int btrfs_remove_ordered_extent(struct inode *inode, 
	int ret;

	int ret;





	tree = &BTRFS_I(inode)->ordered_tree;

	tree = &BTRFS_I(inode)->ordered_tree;

	mutex_lock(&tree->mutex);

	spin_lock(&tree->lock);

	ret = __btrfs_remove_ordered_extent(inode, entry);

	ret = __btrfs_remove_ordered_extent(inode, entry);

	mutex_unlock(&tree->mutex);

	spin_unlock(&tree->lock);

	wake_up(&entry->wait);

	wake_up(&entry->wait);





	return ret;

	return ret;
@@ -567,7 +567,7 @@ struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode, 
	struct btrfs_ordered_extent *entry = NULL;

	struct btrfs_ordered_extent *entry = NULL;





	tree = &BTRFS_I(inode)->ordered_tree;

	tree = &BTRFS_I(inode)->ordered_tree;

	mutex_lock(&tree->mutex);

	spin_lock(&tree->lock);

	node = tree_search(tree, file_offset);

	node = tree_search(tree, file_offset);

	if (!node)

	if (!node)

		goto out;

		goto out;
@@ -578,7 +578,7 @@ struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode, 
	if (entry)

	if (entry)

		atomic_inc(&entry->refs);

		atomic_inc(&entry->refs);

out:

out:

	mutex_unlock(&tree->mutex);

	spin_unlock(&tree->lock);

	return entry;

	return entry;

}

}
@@ -594,7 +594,7 @@ btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset) 
	struct btrfs_ordered_extent *entry = NULL;

	struct btrfs_ordered_extent *entry = NULL;





	tree = &BTRFS_I(inode)->ordered_tree;

	tree = &BTRFS_I(inode)->ordered_tree;

	mutex_lock(&tree->mutex);

	spin_lock(&tree->lock);

	node = tree_search(tree, file_offset);

	node = tree_search(tree, file_offset);

	if (!node)

	if (!node)

		goto out;

		goto out;
@@ -602,7 +602,7 @@ btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset) 
	entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);

	entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);

	atomic_inc(&entry->refs);

	atomic_inc(&entry->refs);

out:

out:

	mutex_unlock(&tree->mutex);

	spin_unlock(&tree->lock);

	return entry;

	return entry;

}

}
@@ -629,7 +629,7 @@ int btrfs_ordered_update_i_size(struct inode *inode, u64 offset, 
	else

	else

		offset = ALIGN(offset, BTRFS_I(inode)->root->sectorsize);

		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;

	disk_i_size = BTRFS_I(inode)->disk_i_size;





	/* truncate file */

	/* truncate file */
@@ -735,7 +735,7 @@ int btrfs_ordered_update_i_size(struct inode *inode, u64 offset, 
	 */

	 */

	if (ordered)

	if (ordered)

		__btrfs_remove_ordered_extent(inode, ordered);

		__btrfs_remove_ordered_extent(inode, ordered);

	mutex_unlock(&tree->mutex);

	spin_unlock(&tree->lock);

	if (ordered)

	if (ordered)

		wake_up(&ordered->wait);

		wake_up(&ordered->wait);

	return ret;

	return ret;
@@ -762,7 +762,7 @@ int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr, 
	if (!ordered)

	if (!ordered)

		return 1;

		return 1;





	mutex_lock(&tree->mutex);

	spin_lock(&tree->lock);

	list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {

	list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {

		if (disk_bytenr >= ordered_sum->bytenr) {

		if (disk_bytenr >= ordered_sum->bytenr) {

			num_sectors = ordered_sum->len / sectorsize;

			num_sectors = ordered_sum->len / sectorsize;
@@ -777,7 +777,7 @@ int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr, 
		}

		}

	}

	}

out:

out:

	mutex_unlock(&tree->mutex);

	spin_unlock(&tree->lock);

	btrfs_put_ordered_extent(ordered);

	btrfs_put_ordered_extent(ordered);

	return ret;

	return ret;

}

}

fs/btrfs/ordered-data.h

+2 −2
Original line number Original line Diff line number Diff line
@@ -21,7 +21,7 @@ 




/* one of these per inode */

/* one of these per inode */

struct btrfs_ordered_inode_tree {

struct btrfs_ordered_inode_tree {

	struct mutex mutex;

	spinlock_t lock;

	struct rb_root tree;

	struct rb_root tree;

	struct rb_node *last;

	struct rb_node *last;

};

};
@@ -128,7 +128,7 @@ static inline int btrfs_ordered_sum_size(struct btrfs_root *root, 
static inline void

static inline void

btrfs_ordered_inode_tree_init(struct btrfs_ordered_inode_tree *t)

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->tree = RB_ROOT;

	t->last = NULL;

	t->last = NULL;

}

}