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: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer 2016-01-31 12:08:36 -05:00
parent 591ddcfc4b
commit 8637a6bf14

View File

@ -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 = mempool_create_slab_pool(min_ios, _mpio_cache);
if (!m->mpio_pool) {
kfree(m);
return NULL;
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;
@ -238,10 +251,13 @@ static int set_mapinfo(struct multipath *m, union map_info *info)
static void clear_mapinfo(struct multipath *m, union map_info *info)
{
struct dm_mpath_io *mpio = info->ptr;
/* 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);
info->ptr = NULL;
mempool_free(mpio, m->mpio_pool);
}
}
/*-----------------------------------------------
@ -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;