[PATCH v6 0/2] block/dm: support bio polling

Mike Snitzer
2022-03-07T18:53:12Z

Hi,

I've rebased Ming's latest [1] ontop of dm-5.18 [2] (which is based on
for-5.18/block). End result available in dm-5.18-biopoll branch [3]

These changes add bio polling support to DM. Tested with linear and
striped DM targets.

IOPS improvement was ~5% on my baremetal system with a single Intel
Optane NVMe device (561K hipri=1 vs 530K hipri=0).

Ming has seen better improvement while testing within a VM:
dm-linear: hipri=1 vs hipri=0 15~20% iops improvement
dm-stripe: hipri=1 vs hipri=0 ~30% iops improvement

I'd like to merge these changes via the DM tree when the 5.18 merge
window opens. The first block patch that adds ->poll_bio to
block_device_operations will need review so that I can take it
through the DM tree. Reason for going through the DM tree is there
have been some fairly extensive changes queued in dm-5.18 that build
on for-5.18/block. So I think it easiest to just add the block
depenency via DM tree since DM is first consumer of ->poll_bio

Thanks,
Mike

[1] https://github.com/ming1/linux/commits/my_v5.18-dm-bio-poll
[2] https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/log/?h=dm-5.18
[3] https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/log/?h=dm-5.18-biopoll
[4] https://github.com/ming1/linux/commit/c107c30e15041ac1ce672f56809961406e2a3e52

v6: Ming switched from reusing .bi_end_io to .bi_private and added a
comment to comment-block above dm_get_bio_hlist_head as suggested
by Jens.

v5: remove WARN_ONs in ->poll_bio interface patch. Fixed comment typo
along the way (found while seeing how other
block_device_operations are referenced in block's code comments).

Ming Lei (2):
block: add ->poll_bio to block_device_operations
dm: support bio polling

block/blk-core.c | 14 +++--
block/genhd.c | 4 ++
drivers/md/dm-core.h | 2 +
drivers/md/dm-table.c | 27 ++++++++++
drivers/md/dm.c | 143 +++++++++++++++++++++++++++++++++++++++++++++++--
include/linux/blkdev.h | 2 +
6 files changed, 184 insertions(+), 8 deletions(-)

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2.15.0