Hi Guys,
The 3 paches changes the blk-mq part of blk_insert_cloned_request(),
in which we switch to blk_mq_try_issue_directly(), so that both dm-rq
and blk-mq can get the dispatch result of underlying queue, and with
this information, blk-mq can handle IO merge much better, then
sequential I/O performance is improved much.
In my dm-mpath over virtio-scsi test, this whole patchset improves
sequential IO by 3X ~ 5X.
V4:
- remove dm patches which are in DM tree already
- cleanup __blk_mq_issue_req as suggested by Jens
V3:
- rebase on the latest for-4.16/block of block tree
- add missed pg_init_all_paths() in patch 1, according to Bart's review
V2:
- drop 'dm-mpath: cache ti->clone during requeue', which is a bit
too complicated, and not see obvious performance improvement.
- make change on blk-mq part cleaner
Ming Lei (3):
blk-mq: move actual issue into one helper
blk-mq: return dispatch result to caller in blk_mq_try_issue_directly
blk-mq: issue request directly for blk_insert_cloned_request
block/blk-mq.c | 85 +++++++++++++++++++++++++++++++++++++++++++---------------
1 file changed, 64 insertions(+), 21 deletions(-)
--
2.9.5
