On Tue, 2017-08-01 at 17:07 -0400, Chuck Lever wrote:
> The amount of payload per MR depends on device capabilities and
> the memory registration mode in use. The new rdma_rw API hides both,
> making it difficult for ULPs to determine how large their transport
> send queues need to be.
>
> Expose the MR payload information via a new API.
>
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Acked-by: Doug Ledford <dledford@xxxxxxxxxx>
> ---
> drivers/infiniband/core/rw.c | 24 ++++++++++++++++++++++++
> include/rdma/rw.h | 2 ++
> 2 files changed, 26 insertions(+)
>
> diff --git a/drivers/infiniband/core/rw.c
> b/drivers/infiniband/core/rw.c
> index dbfd854..6ca607e 100644
> --- a/drivers/infiniband/core/rw.c
> +++ b/drivers/infiniband/core/rw.c
> @@ -643,6 +643,30 @@ void rdma_rw_ctx_destroy_signature(struct
> rdma_rw_ctx *ctx, struct ib_qp *qp,
> }
> EXPORT_SYMBOL(rdma_rw_ctx_destroy_signature);
>
> +/**
> + * rdma_rw_mr_factor - return number of MRs required for a payload
> + * @device: device handling the connection
> + * @port_num: port num to which the connection is bound
> + * @maxpages: maximum payload pages per rdma_rw_ctx
> + *
> + * Returns the number of MRs the device requires to move @maxpayload
> + * bytes. The returned value is used during transport creation to
> + * compute max_rdma_ctxts and the size of the transport's Send and
> + * Send Completion Queues.
> + */
> +unsigned int rdma_rw_mr_factor(struct ib_device *device, u8
> port_num,
> + unsigned int maxpages)
> +{
> + unsigned int mr_pages;
> +
> + if (rdma_rw_can_use_mr(device, port_num))
> + mr_pages = rdma_rw_fr_page_list_len(device);
> + else
> + mr_pages = device->attrs.max_sge_rd;
> + return DIV_ROUND_UP(maxpages, mr_pages);
> +}
> +EXPORT_SYMBOL(rdma_rw_mr_factor);
> +
> void rdma_rw_init_qp(struct ib_device *dev, struct ib_qp_init_attr
> *attr)
> {
> u32 factor;
> diff --git a/include/rdma/rw.h b/include/rdma/rw.h
> index 377d865..a3cbbc7 100644
> --- a/include/rdma/rw.h
> +++ b/include/rdma/rw.h
> @@ -81,6 +81,8 @@ struct ib_send_wr *rdma_rw_ctx_wrs(struct
> rdma_rw_ctx *ctx, struct ib_qp *qp,
> int rdma_rw_ctx_post(struct rdma_rw_ctx *ctx, struct ib_qp *qp, u8
> port_num,
> struct ib_cqe *cqe, struct ib_send_wr *chain_wr);
>
> +unsigned int rdma_rw_mr_factor(struct ib_device *device, u8
> port_num,
> + unsigned int maxpages);
> void rdma_rw_init_qp(struct ib_device *dev, struct ib_qp_init_attr
> *attr);
> int rdma_rw_init_mrs(struct ib_qp *qp, struct ib_qp_init_attr
> *attr);
> void rdma_rw_cleanup_mrs(struct ib_qp *qp);
>
> --
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--
Doug Ledford <dledford@xxxxxxxxxx>
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