Commit 8637a6bf authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm mpath: use blk-mq pdu for per-request 'struct dm_mpath_io' 



Allow the multipath target to avoid making small allocations for each
'struct dm_mpath_io' that is needed for each request.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 591ddcfc

drivers/md/dm-mpath.c

+29 −10
Original line number Diff line number Diff line
@@ -181,10 +181,9 @@ static void free_priority_group(struct priority_group *pg, 
	kfree(pg);

}



static struct multipath *alloc_multipath(struct dm_target *ti)

static struct multipath *alloc_multipath(struct dm_target *ti, bool use_blk_mq)

{

	struct multipath *m;

	unsigned min_ios = dm_get_reserved_rq_based_ios();



	m = kzalloc(sizeof(*m), GFP_KERNEL);

	if (m) {
@@ -195,11 +194,18 @@ static struct multipath *alloc_multipath(struct dm_target *ti) 
		INIT_WORK(&m->trigger_event, trigger_event);

		init_waitqueue_head(&m->pg_init_wait);

		mutex_init(&m->work_mutex);



		m->mpio_pool = NULL;

		if (!use_blk_mq) {

			unsigned min_ios = dm_get_reserved_rq_based_ios();



			m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache);

			if (!m->mpio_pool) {

				kfree(m);

				return NULL;

			}

		}



		m->ti = ti;

		ti->private = m;

	}
@@ -226,6 +232,13 @@ static int set_mapinfo(struct multipath *m, union map_info *info) 
{

	struct dm_mpath_io *mpio;



	if (!m->mpio_pool) {

		/* Use blk-mq pdu memory requested via per_io_data_size */

		mpio = info->ptr;

		memset(mpio, 0, sizeof(*mpio));

		return mpio;

	}



	mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC);

	if (!mpio)

		return -ENOMEM;
@@ -238,11 +251,14 @@ static int set_mapinfo(struct multipath *m, union map_info *info) 


static void clear_mapinfo(struct multipath *m, union map_info *info)

{

	/* Only needed for non blk-mq */

	if (m->mpio_pool) {

		struct dm_mpath_io *mpio = info->ptr;



		info->ptr = NULL;

		mempool_free(mpio, m->mpio_pool);

	}

}



/*-----------------------------------------------

 * Path selection
@@ -827,11 +843,12 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc, 
	struct dm_arg_set as;

	unsigned pg_count = 0;

	unsigned next_pg_num;

	bool use_blk_mq = dm_use_blk_mq(dm_table_get_md(ti->table));



	as.argc = argc;

	as.argv = argv;



	m = alloc_multipath(ti);

	m = alloc_multipath(ti, use_blk_mq);

	if (!m) {

		ti->error = "can't allocate multipath";

		return -EINVAL;
@@ -887,6 +904,8 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc, 
	ti->num_flush_bios = 1;

	ti->num_discard_bios = 1;

	ti->num_write_same_bios = 1;

	if (use_blk_mq)

		ti->per_io_data_size = sizeof(struct dm_mpath_io);



	return 0;