diff options
author | Chris Mason <chris.mason@oracle.com> | 2009-09-02 22:24:52 +0200 |
---|---|---|
committer | Chris Mason <chris.mason@oracle.com> | 2009-09-11 19:31:05 +0200 |
commit | 890871be854b5f5e43e7ba2475f706209906cc24 (patch) | |
tree | 9d087adf7a28bb910992d07d93ea2a992e394110 /fs/btrfs/disk-io.c | |
parent | Btrfs: tweak congestion backoff (diff) | |
download | linux-890871be854b5f5e43e7ba2475f706209906cc24.tar.xz linux-890871be854b5f5e43e7ba2475f706209906cc24.zip |
Btrfs: switch extent_map to a rw lock
There are two main users of the extent_map tree. The
first is regular file inodes, where it is evenly spread
between readers and writers.
The second is the chunk allocation tree, which maps blocks from
logical addresses to phyiscal ones, and it is 99.99% reads.
The mapping tree is a point of lock contention during heavy IO
workloads, so this commit switches things to a rw lock.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/disk-io.c')
-rw-r--r-- | fs/btrfs/disk-io.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 20cefc6f22c4..b6cfdd9164e2 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -121,15 +121,15 @@ static struct extent_map *btree_get_extent(struct inode *inode, struct extent_map *em; int ret; - spin_lock(&em_tree->lock); + read_lock(&em_tree->lock); em = lookup_extent_mapping(em_tree, start, len); if (em) { em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; - spin_unlock(&em_tree->lock); + read_unlock(&em_tree->lock); goto out; } - spin_unlock(&em_tree->lock); + read_unlock(&em_tree->lock); em = alloc_extent_map(GFP_NOFS); if (!em) { @@ -142,7 +142,7 @@ static struct extent_map *btree_get_extent(struct inode *inode, em->block_start = 0; em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; - spin_lock(&em_tree->lock); + write_lock(&em_tree->lock); ret = add_extent_mapping(em_tree, em); if (ret == -EEXIST) { u64 failed_start = em->start; @@ -161,7 +161,7 @@ static struct extent_map *btree_get_extent(struct inode *inode, free_extent_map(em); em = NULL; } - spin_unlock(&em_tree->lock); + write_unlock(&em_tree->lock); if (ret) em = ERR_PTR(ret); @@ -1323,9 +1323,9 @@ static void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) offset = page_offset(page); em_tree = &BTRFS_I(inode)->extent_tree; - spin_lock(&em_tree->lock); + read_lock(&em_tree->lock); em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE); - spin_unlock(&em_tree->lock); + read_unlock(&em_tree->lock); if (!em) { __unplug_io_fn(bdi, page); return; |