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authorChris Mason <chris.mason@oracle.com>2008-08-15 15:34:18 -0400
committerChris Mason <chris.mason@oracle.com>2008-09-25 11:04:06 -0400
commit53863232ef961778aa414b700ed88a48e8e871e6 (patch)
tree05a74ac264a5fb4f6b8824771f5820ca5907afe5 /fs
parent4854ddd0ed0a687fc2d7c45a529c406232e31e7b (diff)
Btrfs: Lower contention on the csum mutex
This takes the csum mutex deeper in the call chain and releases it more often. Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/async-thread.c3
-rw-r--r--fs/btrfs/disk-io.c9
-rw-r--r--fs/btrfs/file-item.c16
-rw-r--r--fs/btrfs/inode.c2
4 files changed, 22 insertions, 8 deletions
diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 958cd8b5f0d..2ee30174019 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -48,6 +48,7 @@ struct btrfs_worker_thread {
/* number of things on the pending list */
atomic_t num_pending;
+
unsigned long sequence;
/* protects the pending list. */
@@ -242,7 +243,7 @@ static struct btrfs_worker_thread *next_worker(struct btrfs_workers *workers)
worker = list_entry(next, struct btrfs_worker_thread, worker_list);
atomic_inc(&worker->num_pending);
worker->sequence++;
- if (worker->sequence % 4 == 0)
+ if (worker->sequence % workers->idle_thresh == 0)
list_move_tail(next, &workers->worker_list);
return worker;
}
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 1aed1f4616b..92e14dd9bdd 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1386,7 +1386,14 @@ struct btrfs_root *open_ctree(struct super_block *sb,
* devices
*/
fs_info->submit_workers.idle_thresh = 64;
- fs_info->workers.idle_thresh = 32;
+
+ /* fs_info->workers is responsible for checksumming file data
+ * blocks and metadata. Using a larger idle thresh allows each
+ * worker thread to operate on things in roughly the order they
+ * were sent by the writeback daemons, improving overall locality
+ * of the IO going down the pipe.
+ */
+ fs_info->workers.idle_thresh = 128;
btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1);
btrfs_init_workers(&fs_info->endio_workers, "endio",
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 51aba8cee7c..9454e0a07c8 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -321,6 +321,7 @@ again:
file_key.offset = offset;
btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
+ mutex_lock(&BTRFS_I(inode)->csum_mutex);
item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
if (!IS_ERR(item)) {
leaf = path->nodes[0];
@@ -367,7 +368,7 @@ again:
ret = btrfs_search_slot(trans, root, &file_key, path,
BTRFS_CRC32_SIZE, 1);
if (ret < 0)
- goto fail;
+ goto fail_unlock;
if (ret == 0) {
BUG();
}
@@ -411,10 +412,10 @@ insert:
ret = btrfs_insert_empty_item(trans, root, path, &file_key,
ins_size);
if (ret < 0)
- goto fail;
+ goto fail_unlock;
if (ret != 0) {
WARN_ON(1);
- goto fail;
+ goto fail_unlock;
}
csum:
leaf = path->nodes[0];
@@ -427,6 +428,8 @@ found:
item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
btrfs_item_size_nr(leaf, path->slots[0]));
eb_token = NULL;
+ mutex_unlock(&BTRFS_I(inode)->csum_mutex);
+ cond_resched();
next_sector:
if (!eb_token ||
@@ -467,13 +470,18 @@ next_sector:
eb_token = NULL;
}
btrfs_mark_buffer_dirty(path->nodes[0]);
+ cond_resched();
if (total_bytes < sums->len) {
btrfs_release_path(root, path);
goto again;
}
-fail:
+out:
btrfs_free_path(path);
return ret;
+
+fail_unlock:
+ mutex_unlock(&BTRFS_I(inode)->csum_mutex);
+ goto out;
}
int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 33b990878d8..65107894a5b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -415,10 +415,8 @@ static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
btrfs_set_trans_block_group(trans, inode);
list_for_each(cur, list) {
sum = list_entry(cur, struct btrfs_ordered_sum, list);
- mutex_lock(&BTRFS_I(inode)->csum_mutex);
btrfs_csum_file_blocks(trans, BTRFS_I(inode)->root,
inode, sum);
- mutex_unlock(&BTRFS_I(inode)->csum_mutex);
}
return 0;
}