Re: [PATCHv5 for-next 13/19] block/rnbd-clt: Support polling mode for IO latency optimization

[Leon Romanovsky <leonro@nvidia.com>]

On Mon, Apr 19, 2021 at 09:37:16AM +0200, Gioh Kim wrote:
> From: Gioh Kim <gi-oh.kim@cloud.ionos.com>
> 
> RNBD can make double-queues for irq-mode and poll-mode.
> For example, on 4-CPU system 8 request-queues are created,
> 4 for irq-mode and 4 for poll-mode.
> If the IO has HIPRI flag, the block-layer will call .poll function
> of RNBD. Then IO is sent to the poll-mode queue.
> Add optional nr_poll_queues argument for map_devices interface.
> 
> To support polling of RNBD, RTRS client creates connections
> for both of irq-mode and direct-poll-mode.
> 
> For example, on 4-CPU system it could've create 5 connections:
> con[0] => user message (softirq cq)
> con[1:4] => softirq cq
> 
> After this patch, it can create 9 connections:
> con[0] => user message (softirq cq)
> con[1:4] => softirq cq
> con[5:8] => DIRECT-POLL cq
> 
> Cc: Leon Romanovsky <leonro@nvidia.com>
> Cc: linux-rdma@vger.kernel.org
> Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
> Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
> Acked-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/block/rnbd/rnbd-clt-sysfs.c    | 55 ++++++++++++----
>  drivers/block/rnbd/rnbd-clt.c          | 89 +++++++++++++++++++++++---
>  drivers/block/rnbd/rnbd-clt.h          |  5 +-
>  drivers/infiniband/ulp/rtrs/rtrs-clt.c | 62 ++++++++++++++----
>  drivers/infiniband/ulp/rtrs/rtrs-pri.h |  1 +
>  drivers/infiniband/ulp/rtrs/rtrs.h     |  3 +-
>  6 files changed, 181 insertions(+), 34 deletions(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>