From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chuck Lever Subject: [PATCH RFC 2/3] rdma core: Add rdma_rw_mr_payload() Date: Tue, 01 Aug 2017 17:07:07 -0400 Message-ID: <20170801210707.15781.36464.stgit@klimt.1015granger.net> References: <20170801205334.15781.18761.stgit@klimt.1015granger.net> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170801205334.15781.18761.stgit-Hs+gFlyCn65vLzlybtyyYzGyq/o6K9yX@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org 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 --- 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); -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html