From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: [PATCH RFC 2/3] rdma core: Add rdma_rw_mr_payload() Date: Fri, 18 Aug 2017 12:51:29 -0400 Message-ID: <1503075089.2598.26.camel@redhat.com> References: <20170801205334.15781.18761.stgit@klimt.1015granger.net> <20170801210707.15781.36464.stgit@klimt.1015granger.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170801210707.15781.36464.stgit-Hs+gFlyCn65vLzlybtyyYzGyq/o6K9yX@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Chuck Lever , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org 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 Acked-by: Doug Ledford > --- > 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 -- Doug Ledford GPG KeyID: B826A3330E572FDD Key fingerprint = AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD -- 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