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Commit 53863232 authored by Chris Mason's avatar Chris Mason
Browse files

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
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+2 −1
Original line number Original line Diff line number Diff line
@@ -48,6 +48,7 @@ struct btrfs_worker_thread {


	/* number of things on the pending list */
	/* number of things on the pending list */
	atomic_t num_pending;
	atomic_t num_pending;

	unsigned long sequence;
	unsigned long sequence;


	/* protects the pending list. */
	/* 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);
	worker = list_entry(next, struct btrfs_worker_thread, worker_list);
	atomic_inc(&worker->num_pending);
	atomic_inc(&worker->num_pending);
	worker->sequence++;
	worker->sequence++;
	if (worker->sequence % 4 == 0)
	if (worker->sequence % workers->idle_thresh == 0)
		list_move_tail(next, &workers->worker_list);
		list_move_tail(next, &workers->worker_list);
	return worker;
	return worker;
}
}
+8 −1
Original line number Original line Diff line number Diff line
@@ -1386,7 +1386,14 @@ struct btrfs_root *open_ctree(struct super_block *sb,
	 * devices
	 * devices
	 */
	 */
	fs_info->submit_workers.idle_thresh = 64;
	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->fixup_workers, "fixup", 1);
	btrfs_init_workers(&fs_info->endio_workers, "endio",
	btrfs_init_workers(&fs_info->endio_workers, "endio",
+12 −4
Original line number Original line Diff line number Diff line
@@ -321,6 +321,7 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
	file_key.offset = offset;
	file_key.offset = offset;
	btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
	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);
	item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
	if (!IS_ERR(item)) {
	if (!IS_ERR(item)) {
		leaf = path->nodes[0];
		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,
	ret = btrfs_search_slot(trans, root, &file_key, path,
				BTRFS_CRC32_SIZE, 1);
				BTRFS_CRC32_SIZE, 1);
	if (ret < 0)
	if (ret < 0)
		goto fail;
		goto fail_unlock;
	if (ret == 0) {
	if (ret == 0) {
		BUG();
		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,
	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
				      ins_size);
				      ins_size);
	if (ret < 0)
	if (ret < 0)
		goto fail;
		goto fail_unlock;
	if (ret != 0) {
	if (ret != 0) {
		WARN_ON(1);
		WARN_ON(1);
		goto fail;
		goto fail_unlock;
	}
	}
csum:
csum:
	leaf = path->nodes[0];
	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 +
	item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
				      btrfs_item_size_nr(leaf, path->slots[0]));
				      btrfs_item_size_nr(leaf, path->slots[0]));
	eb_token = NULL;
	eb_token = NULL;
	mutex_unlock(&BTRFS_I(inode)->csum_mutex);
	cond_resched();
next_sector:
next_sector:


	if (!eb_token ||
	if (!eb_token ||
@@ -467,13 +470,18 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
		eb_token = NULL;
		eb_token = NULL;
	}
	}
	btrfs_mark_buffer_dirty(path->nodes[0]);
	btrfs_mark_buffer_dirty(path->nodes[0]);
	cond_resched();
	if (total_bytes < sums->len) {
	if (total_bytes < sums->len) {
		btrfs_release_path(root, path);
		btrfs_release_path(root, path);
		goto again;
		goto again;
	}
	}
fail:
out:
	btrfs_free_path(path);
	btrfs_free_path(path);
	return ret;
	return ret;

fail_unlock:
	mutex_unlock(&BTRFS_I(inode)->csum_mutex);
	goto out;
}
}


int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
+0 −2
Original line number Original line Diff line number Diff line
@@ -415,10 +415,8 @@ static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
	btrfs_set_trans_block_group(trans, inode);
	btrfs_set_trans_block_group(trans, inode);
	list_for_each(cur, list) {
	list_for_each(cur, list) {
		sum = list_entry(cur, struct btrfs_ordered_sum, 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,
		btrfs_csum_file_blocks(trans, BTRFS_I(inode)->root,
				       inode, sum);
				       inode, sum);
		mutex_unlock(&BTRFS_I(inode)->csum_mutex);
	}
	}
	return 0;
	return 0;
}
}