Re: [PATCH 0/6] blk-mq: optimize the queue_rqs() support

[Chengming Zhou]

On 2023/8/24 22:43, chengming.zhou@xxxxxxxxx wrote:
> From: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
> 
> The current queue_rqs() support has limitation that it can't work on
> shared tags queue, which is resolved by patch 1-3. We move the account
> of active requests to where we really allocate the driver tag.
> 
> This is clearer and matched with the unaccount side which now happen
> when we put the driver tag. And we can remove RQF_MQ_INFLIGHT, which
> was used to avoid double account problem of flush request.
> 
> Another problem is that the driver that support queue_rqs() has to
> set inflight request table by itself, which is resolved in patch 4.
> 
> The patch 5 fixes a potential race problem which may cause false
> timeout because of the reorder of rq->state and rq->deadline.
> 
> The patch 6 add support queue_rqs() for null_blk, which showed a
> 3.6% IOPS improvement in fio/t/io_uring benchmark on my test VM.
> And we also use it for testing queue_rqs() on shared tags queue.

Hello, gentle ping.

Thanks.

> 
> Thanks for review!
> 
> Chengming Zhou (6):
>   blk-mq: account active requests when get driver tag
>   blk-mq: remove RQF_MQ_INFLIGHT
>   blk-mq: support batched queue_rqs() on shared tags queue
>   blk-mq: update driver tags request table when start request
>   blk-mq: fix potential reorder of request state and deadline
>   block/null_blk: add queue_rqs() support
> 
>  block/blk-flush.c             | 11 ++-----
>  block/blk-mq-debugfs.c        |  1 -
>  block/blk-mq.c                | 53 ++++++++++++++------------------
>  block/blk-mq.h                | 57 ++++++++++++++++++++++++-----------
>  drivers/block/null_blk/main.c | 20 ++++++++++++
>  drivers/block/virtio_blk.c    |  2 --
>  drivers/nvme/host/pci.c       |  1 -
>  include/linux/blk-mq.h        |  2 --
>  8 files changed, 84 insertions(+), 63 deletions(-)
>