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Btrfs: change the ordered tree to use a spinlock instead of a mutex

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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>
This commit is contained in:
Josef Bacik 2010-02-02 21:48:28 +00:00 committed by Chris Mason
parent 4125bf761c
commit 49958fd7db
2 changed files with 19 additions and 19 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

34
fs/btrfs/ordered-data.c
View file

@ -174,7 +174,6 @@ int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
if (!entry)
return -ENOMEM;
mutex_lock(&tree->mutex);
entry->file_offset = file_offset;
entry->start = start;
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->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 @@ int btrfs_add_ordered_sum(struct inode *inode,
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 btrfs_dec_test_ordered_pending(struct inode *inode,
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 @@ int btrfs_dec_test_ordered_pending(struct inode *inode,
else
ret = 1;
out:
mutex_unlock(&tree->mutex);
spin_unlock(&tree->lock);
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
* 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 btrfs_remove_ordered_extent(struct inode *inode,
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 *btrfs_lookup_ordered_extent(struct inode *inode,
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 @@ struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
if (entry)
atomic_inc(&entry->refs);
out:
mutex_unlock(&tree->mutex);
spin_unlock(&tree->lock);
return entry;
}
@ -594,7 +594,7 @@ btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
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 @@ btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
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 @@ int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
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 @@ int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
*/
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 @@ int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
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 @@ int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
}
}
out:
mutex_unlock(&tree->mutex);
spin_unlock(&tree->lock);
btrfs_put_ordered_extent(ordered);
return ret;
}

4
fs/btrfs/ordered-data.h
View file

@ -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 int btrfs_ordered_sum_size(struct btrfs_root *root,
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;
}