tree 7b583e5d4e3f0487a4804900ecfc510addfb0ee9
parent 67cae4c948a5311121905a2a8740c50daf7f6478
author Jens Axboe <axboe@kernel.dk> 1540923844 -0600
committer Jens Axboe <axboe@kernel.dk> 1541623500 -0700

blk-mq: improve plug list sorting

Currently we only look at the software queue, but with support
for multiple maps, we should also look at the hardware queue.
This is important since we'll flush out the request list if
either the software queue or hardware queue don't match.

This sorts by software queue first, then hardware queue if
that differs. Finally we sort by request location like before.
This minimizes the flush points per plug list.

Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>