On 3/19/21 12:48 AM, Ming Lei wrote:
> Hi,
>
> Add per-task io poll context for holding HIPRI blk-mq/underlying bios
> queued from bio based driver's io submission context, and reuse one bio
> padding field for storing 'cookie' returned from submit_bio() for these
> bios. Also explicitly end these bios in poll context by adding two
> new bio flags.
>
> In this way, we needn't to poll all underlying hw queues any more,
> which is implemented in Jeffle's patches. And we can just poll hw queues
> in which there is HIPRI IO queued.
>
> Usually io submission and io poll share same context, so the added io
> poll context data is just like one stack variable, and the cost for
> saving bios is cheap.
>
> Any comments are welcome.
>
> V2:
> - address queue depth scalability issue reported by Jeffle via bio
> group list. Reuse .bi_end_io for linking bios which share same
> .bi_end_io, and support 32 such groups in submit queue. With this way,
> the scalability issue caused by kfifio is solved. Before really
> ending bio, .bi_end_io is recovered from the group head.
I have retested this latest version, and it seems the scaling issue has
been fixed at the first glance.
Test results with the latest version:
3-threads dm-stripe-3 targets (12k randread IOPS, unit K)
317 -> 409 (iodepth=128)
Compared to the test results of v1:
3-threads dm-stripe-3 targets (12k randread IOPS, unit K)
313 -> 349 (iodepth=128, kfifo queue depth =128)
313 -> 409 (iodepth=32, kfifo queue depth =128)
314 -> 409 (iodepth=128, kfifo queue depth =512)
>
>
> Jeffle Xu (4):
> block/mq: extract one helper function polling hw queue
> block: add queue_to_disk() to get gendisk from request_queue
> block: add poll_capable method to support bio-based IO polling
> dm: support IO polling for bio-based dm device
>
> Ming Lei (9):
> block: add helper of blk_queue_poll
> block: add one helper to free io_context
> block: add helper of blk_create_io_context
> block: create io poll context for submission and poll task
> block: add req flag of REQ_TAG
> block: add new field into 'struct bvec_iter'
> block: prepare for supporting bio_list via other link
> block: use per-task poll context to implement bio based io poll
> blk-mq: limit hw queues to be polled in each blk_poll()
>
> block/bio.c | 5 +
> block/blk-core.c | 248 ++++++++++++++++++++++++++++++++--
> block/blk-ioc.c | 12 +-
> block/blk-mq.c | 232 ++++++++++++++++++++++++++++++-
> block/blk-sysfs.c | 14 +-
> block/blk.h | 55 ++++++++
> drivers/md/dm-table.c | 24 ++++
> drivers/md/dm.c | 14 ++
> drivers/nvme/host/core.c | 2 +-
> include/linux/bio.h | 132 +++++++++---------
> include/linux/blk_types.h | 20 ++-
> include/linux/blkdev.h | 4 +
> include/linux/bvec.h | 9 ++
> include/linux/device-mapper.h | 1 +
> include/linux/iocontext.h | 2 +
> include/trace/events/kyber.h | 6 +-
> 16 files changed, 686 insertions(+), 94 deletions(-)
>
--
Thanks,
Jeffle
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