[dm-devel] [PATCH for-4.9 0/3] allow delayed requeue of blk-mq requests

[Mike Snitzer]

I'd like to see these changes included during the 4.9 merge.  The
blk-mq change is a straight-forward switch from work_struct to
delayed_work and the addition of the blk_mq_delay_kick_requeue_list()
interface.  Jens, can you pick up this blk-mq changes (patch 1)?

These changes offer reduced CPU utilization during DM multipath's all
path down case (when 'queue_if_no_path' is enabled).  Please see each
patch's header for more details.

Mike Snitzer (3):
  blk-mq: introduce blk_mq_delay_kick_requeue_list()
  dm rq: add DM_MAPIO_DELAY_REQUEUE to delay requeue of blk-mq requests
  dm mpath: delay the requeue of blk-mq requests while all paths down

 block/blk-mq.c                | 15 +++++++++++----
 drivers/md/dm-mpath.c         | 15 +++++++++------
 drivers/md/dm-rq.c            | 35 ++++++++++++++++++++---------------
 include/linux/blk-mq.h        |  1 +
 include/linux/blkdev.h        |  2 +-
 include/linux/device-mapper.h |  1 +
 6 files changed, 43 insertions(+), 26 deletions(-)

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2.7.4 (Apple Git-66)