dm rq: add DM_MAPIO_DELAY_REQUEUE to delay requeue of blk-mq requests

Otherwise blk-mq will immediately dispatch requests that are requeued
via a BLK_MQ_RQ_QUEUE_BUSY return from blk_mq_ops .queue_rq.

Delayed requeue is implemented using blk_mq_delay_kick_requeue_list()
with a delay of 5 secs.  In the context of DM multipath (all paths down)
it doesn't make any sense to requeue more quickly.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer 2016-09-09 19:24:57 -04:00
commit a8ac51e4ab
2 changed files with 19 additions and 14 deletions