Btrfs: try to avoid acquiring free space ctl's lock

We don't need to take the lock if the block group has not been cached.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Liu Bo 2017-02-13 15:42:30 -08:00 committed by David Sterba
parent 6f6b643e44
commit 0c9b36e0d7

View File

@ -7714,18 +7714,20 @@ static noinline int find_free_extent(struct btrfs_root *orig_root,
last_ptr->fragmented = 1;
spin_unlock(&last_ptr->lock);
}
spin_lock(&block_group->free_space_ctl->tree_lock);
if (cached &&
block_group->free_space_ctl->free_space <
num_bytes + empty_cluster + empty_size) {
if (block_group->free_space_ctl->free_space >
max_extent_size)
max_extent_size =
block_group->free_space_ctl->free_space;
spin_unlock(&block_group->free_space_ctl->tree_lock);
goto loop;
if (cached) {
struct btrfs_free_space_ctl *ctl =
block_group->free_space_ctl;
spin_lock(&ctl->tree_lock);
if (ctl->free_space <
num_bytes + empty_cluster + empty_size) {
if (ctl->free_space > max_extent_size)
max_extent_size = ctl->free_space;
spin_unlock(&ctl->tree_lock);
goto loop;
}
spin_unlock(&ctl->tree_lock);
}
spin_unlock(&block_group->free_space_ctl->tree_lock);
offset = btrfs_find_space_for_alloc(block_group, search_start,
num_bytes, empty_size,