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Commit f177940a authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm cache metadata: switch to using the new cursor api for loading metadata 



This change offers a pretty significant performance improvement.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent fdd1315a

drivers/md/dm-cache-metadata.c

+80 −23
Original line number Diff line number Diff line
@@ -140,6 +140,13 @@ struct dm_cache_metadata { 
	 * the device.

	 */

	bool fail_io:1;



	/*

	 * These structures are used when loading metadata.  They're too

	 * big to put on the stack.

	 */

	struct dm_array_cursor mapping_cursor;

	struct dm_array_cursor hint_cursor;

};



/*-------------------------------------------------------------------
@@ -1171,31 +1178,37 @@ static bool hints_array_available(struct dm_cache_metadata *cmd, 
		hints_array_initialized(cmd);

}



static int __load_mapping(void *context, uint64_t cblock, void *leaf)

static int __load_mapping(struct dm_cache_metadata *cmd,

			  uint64_t cb, bool hints_valid,

			  struct dm_array_cursor *mapping_cursor,

			  struct dm_array_cursor *hint_cursor,

			  load_mapping_fn fn, void *context)

{

	int r = 0;

	bool dirty;

	__le64 value;

	__le32 hint_value = 0;



	__le64 mapping;

	__le32 hint = 0;



	__le64 *mapping_value_le;

	__le32 *hint_value_le;



	dm_oblock_t oblock;

	unsigned flags;

	struct thunk *thunk = context;

	struct dm_cache_metadata *cmd = thunk->cmd;



	memcpy(&value, leaf, sizeof(value));

	unpack_value(value, &oblock, &flags);

	dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);

	memcpy(&mapping, mapping_value_le, sizeof(mapping));

	unpack_value(mapping, &oblock, &flags);



	if (flags & M_VALID) {

		if (thunk->hints_valid) {

			r = dm_array_get_value(&cmd->hint_info, cmd->hint_root,

					       cblock, &hint_value);

			if (r && r != -ENODATA)

				return r;

		if (hints_valid) {

			dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);

			memcpy(&hint, hint_value_le, sizeof(hint));

		}



		dirty = thunk->respect_dirty_flags ? (flags & M_DIRTY) : true;

		r = thunk->fn(thunk->context, oblock, to_cblock(cblock),

			      dirty, le32_to_cpu(hint_value), thunk->hints_valid);

		r = fn(context, oblock, to_cblock(cb), flags & M_DIRTY,

		       le32_to_cpu(hint), hints_valid);

		if (r)

			DMERR("policy couldn't load cblock");

	}



	return r;
@@ -1205,16 +1218,60 @@ static int __load_mappings(struct dm_cache_metadata *cmd, 
			   struct dm_cache_policy *policy,

			   load_mapping_fn fn, void *context)

{

	struct thunk thunk;

	int r;

	uint64_t cb;



	thunk.fn = fn;

	thunk.context = context;

	bool hints_valid = hints_array_available(cmd, policy);



	thunk.cmd = cmd;

	thunk.respect_dirty_flags = cmd->clean_when_opened;

	thunk.hints_valid = hints_array_available(cmd, policy);

	if (from_cblock(cmd->cache_blocks) == 0)

		/* Nothing to do */

		return 0;



	r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor);

	if (r)

		return r;



	return dm_array_walk(&cmd->info, cmd->root, __load_mapping, &thunk);

	if (hints_valid) {

		r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor);

		if (r) {

			dm_array_cursor_end(&cmd->mapping_cursor);

			return r;

		}

	}



	for (cb = 0; ; cb++) {

		r = __load_mapping(cmd, cb, hints_valid,

				   &cmd->mapping_cursor, &cmd->hint_cursor,

				   fn, context);

		if (r)

			goto out;



		/*

		 * We need to break out before we move the cursors.

		 */

		if (cb >= (from_cblock(cmd->cache_blocks) - 1))

			break;



		r = dm_array_cursor_next(&cmd->mapping_cursor);

		if (r) {

			DMERR("dm_array_cursor_next for mapping failed");

			goto out;

		}



		if (hints_valid) {

			r = dm_array_cursor_next(&cmd->hint_cursor);

			if (r) {

				DMERR("dm_array_cursor_next for hint failed");

				goto out;

			}

		}

	}

out:

	dm_array_cursor_end(&cmd->mapping_cursor);

	if (hints_valid)

		dm_array_cursor_end(&cmd->hint_cursor);



	return r;

}



int dm_cache_load_mappings(struct dm_cache_metadata *cmd,