[0/3] blk-mq: Support sharing tags across hardware queues

Message

Bart Van Assche Nov. 26, 2019, 5:56 p.m. UTC

Hi Jens,

Although the block layer already supports sharing hardware queues across
request queues, it does not yet support sharing tags across hardware queues.
Some SCSI hardware needs this functionality because this is a good match for
how some SCSI HBA's work. This patch does not incur a performance overhead
for block drivers that do not share tags across hardware queues.

Note: my original plan was to post this patch series after the merge window
has closed. I'm posting this now to allow comparison with alternative
approaches.

Thanks,

Bart.

Bart Van Assche (2):
  blk-mq: Move the TAG_ACTIVE and SCHED_RESTART flags from hctx into
    blk_mq_tags
  block: Add support for sharing tags across hardware queues

John Garry (1):
  blk-mq: Remove some unused function arguments

 block/blk-mq-debugfs.c | 42 ++++++++++++++++++++++++++++++++++++++----
 block/blk-mq-sched.c   |  8 ++++----
 block/blk-mq-sched.h   |  2 +-
 block/blk-mq-tag.c     | 19 +++++++++++--------
 block/blk-mq-tag.h     | 13 +++++++++++--
 block/blk-mq.c         | 38 +++++++++++++++++++++++++-------------
 block/blk-mq.h         |  2 +-
 include/linux/blk-mq.h | 10 ++++++----
 8 files changed, 97 insertions(+), 37 deletions(-)