[PATCH 5/5] nvme: enable batched completions of passthrough IO

[Anuj gupta]

On Tue, Sep 27, 2022 at 7:19 AM Jens Axboe <axboe at kernel.dk> wrote:
>
> Now that the normal passthrough end_io path doesn't need the request
> anymore, we can kill the explicit blk_mq_free_request() and just pass
> back RQ_END_IO_FREE instead. This enables the batched completion from
> freeing batches of requests at the time.
>
> This brings passthrough IO performance at least on par with bdev based
> O_DIRECT with io_uring. With this and batche allocations, peak performance
> goes from 110M IOPS to 122M IOPS. For IRQ based, passthrough is now also
> about 10% faster than previously, going from ~61M to ~67M IOPS.
>
> Co-developed-by: Stefan Roesch <shr at fb.com>
> Signed-off-by: Jens Axboe <axboe at kernel.dk>
> ---
>  drivers/nvme/host/ioctl.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
> index 9e356a6c96c2..d9633f426690 100644
> --- a/drivers/nvme/host/ioctl.c
> +++ b/drivers/nvme/host/ioctl.c
> @@ -423,8 +423,7 @@ static enum rq_end_io_ret nvme_uring_cmd_end_io(struct request *req,
>         else
>                 io_uring_cmd_complete_in_task(ioucmd, nvme_uring_task_cb);
>
> -       blk_mq_free_request(req);
> -       return RQ_END_IO_NONE;
> +       return RQ_END_IO_FREE;
>  }
>
>  static enum rq_end_io_ret nvme_uring_cmd_end_io_meta(struct request *req,
> --
> 2.35.1
>
Looks good to me.
Reviewed-by: Anuj Gupta <anuj20.g at samsung.com>

--
Anuj Gupta