Commit 53863232 authored by Chris Mason's avatar Chris Mason

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: default avatarChris Mason <chris.mason@oracle.com>
parent 4854ddd0
......@@ -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;
}
......
......@@ -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",
......
......@@ -321,6 +321,7 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
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 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
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 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
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 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
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 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
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,
......
......@@ -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;
}
......
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