Josef Bacik
2010-Feb-02 21:48 UTC
[PATCH] 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>
---
fs/btrfs/ordered-data.c | 32 ++++++++++++++++----------------
fs/btrfs/ordered-data.h | 4 ++--
2 files changed, 18 insertions(+), 18 deletions(-)
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index c44054b..724d73f 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -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;
}
@@ -241,7 +241,7 @@ 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;
@@ -269,7 +269,7 @@ out:
*cached = entry;
atomic_inc(&entry->refs);
}
- mutex_unlock(&tree->mutex);
+ spin_unlock(&tree->lock);
return ret == 0;
}
@@ -345,9 +345,9 @@ 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;
@@ -572,7 +572,7 @@ 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;
@@ -583,7 +583,7 @@ 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;
}
@@ -599,7 +599,7 @@ 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;
@@ -607,7 +607,7 @@ 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;
}
@@ -634,7 +634,7 @@ 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 */
@@ -740,7 +740,7 @@ out:
*/
if (ordered)
__btrfs_remove_ordered_extent(inode, ordered);
- mutex_unlock(&tree->mutex);
+ spin_unlock(&tree->lock);
if (ordered)
wake_up(&ordered->wait);
return ret;
@@ -767,7 +767,7 @@ 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;
@@ -782,7 +782,7 @@ 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;
}
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index 398bfc6..d7f359a 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 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_node = NULL;
t->last = NULL;
}
--
1.6.6
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