Return-Path: Received: from mail-pd0-f170.google.com ([209.85.192.170]:36595 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753416AbbGJL3V (ORCPT ); Fri, 10 Jul 2015 07:29:21 -0400 Received: by pdjr16 with SMTP id r16so21734403pdj.3 for ; Fri, 10 Jul 2015 04:29:21 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20150709204305.26247.39173.stgit@manet.1015granger.net> References: <20150709203242.26247.4848.stgit@manet.1015granger.net> <20150709204305.26247.39173.stgit@manet.1015granger.net> Date: Fri, 10 Jul 2015 16:59:21 +0530 Message-ID: Subject: Re: [PATCH v1 09/12] xprtrdma: Prepare rpcrdma_ep_post() for RDMA_NOMSG calls From: Devesh Sharma To: Chuck Lever Cc: linux-rdma@vger.kernel.org, Linux NFS Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: we need to honor the max limits of device by checking dev_attr.max_sge? a vendor may not support 4 sges. On Fri, Jul 10, 2015 at 2:13 AM, Chuck Lever wrote: > Only the RPC/RDMA header is sent when making an RDMA_NOMSG call. > That header resides in the first element of the iovec array > passed to rpcrdma_ep_post(). > > Instead of special casing the iovec element with the pad, just > sync all the elements in the send iovec. Syncing the zero pad is > not strictly necessary, but the pad is rarely if ever used these > days, and the extra cost in that case is small. > > Signed-off-by: Chuck Lever > --- > net/sunrpc/xprtrdma/rpc_rdma.c | 4 ++++ > net/sunrpc/xprtrdma/verbs.c | 27 +++++++++++---------------- > net/sunrpc/xprtrdma/xprt_rdma.h | 18 ++++++++++-------- > 3 files changed, 25 insertions(+), 24 deletions(-) > > diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c > index cb05233..2e721f2 100644 > --- a/net/sunrpc/xprtrdma/rpc_rdma.c > +++ b/net/sunrpc/xprtrdma/rpc_rdma.c > @@ -575,6 +575,10 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst) > req->rl_send_iov[0].length = hdrlen; > req->rl_send_iov[0].lkey = rdmab_lkey(req->rl_rdmabuf); > > + req->rl_niovs = 1; > + if (rtype == rpcrdma_areadch) > + return 0; > + > req->rl_send_iov[1].addr = rdmab_addr(req->rl_sendbuf); > req->rl_send_iov[1].length = rpclen; > req->rl_send_iov[1].lkey = rdmab_lkey(req->rl_sendbuf); > diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c > index cdf5220..9199436 100644 > --- a/net/sunrpc/xprtrdma/verbs.c > +++ b/net/sunrpc/xprtrdma/verbs.c > @@ -651,7 +651,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, > if (rc) > return rc; > ep->rep_attr.cap.max_recv_wr = cdata->max_requests; > - ep->rep_attr.cap.max_send_sge = (cdata->padding ? 4 : 2); > + ep->rep_attr.cap.max_send_sge = RPCRDMA_MAX_IOVS; > ep->rep_attr.cap.max_recv_sge = 1; > ep->rep_attr.cap.max_inline_data = 0; > ep->rep_attr.sq_sig_type = IB_SIGNAL_REQ_WR; > @@ -1303,9 +1303,11 @@ rpcrdma_ep_post(struct rpcrdma_ia *ia, > struct rpcrdma_ep *ep, > struct rpcrdma_req *req) > { > + struct ib_device *device = ia->ri_device; > struct ib_send_wr send_wr, *send_wr_fail; > struct rpcrdma_rep *rep = req->rl_reply; > - int rc; > + struct ib_sge *iov = req->rl_send_iov; > + int i, rc; > > if (rep) { > rc = rpcrdma_ep_post_recv(ia, ep, rep); > @@ -1316,22 +1318,15 @@ rpcrdma_ep_post(struct rpcrdma_ia *ia, > > send_wr.next = NULL; > send_wr.wr_id = RPCRDMA_IGNORE_COMPLETION; > - send_wr.sg_list = req->rl_send_iov; > + send_wr.sg_list = iov; > send_wr.num_sge = req->rl_niovs; > send_wr.opcode = IB_WR_SEND; > - if (send_wr.num_sge == 4) /* no need to sync any pad (constant) */ > - ib_dma_sync_single_for_device(ia->ri_device, > - req->rl_send_iov[3].addr, > - req->rl_send_iov[3].length, > - DMA_TO_DEVICE); > - ib_dma_sync_single_for_device(ia->ri_device, > - req->rl_send_iov[1].addr, > - req->rl_send_iov[1].length, > - DMA_TO_DEVICE); > - ib_dma_sync_single_for_device(ia->ri_device, > - req->rl_send_iov[0].addr, > - req->rl_send_iov[0].length, > - DMA_TO_DEVICE); > + > + for (i = 0; i < send_wr.num_sge; i++) > + ib_dma_sync_single_for_device(device, iov[i].addr, > + iov[i].length, DMA_TO_DEVICE); > + dprintk("RPC: %s: posting %d s/g entries\n", > + __func__, send_wr.num_sge); > > if (DECR_CQCOUNT(ep) > 0) > send_wr.send_flags = 0; > diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h > index ce4e79e..90da480 100644 > --- a/net/sunrpc/xprtrdma/xprt_rdma.h > +++ b/net/sunrpc/xprtrdma/xprt_rdma.h > @@ -256,16 +256,18 @@ struct rpcrdma_mr_seg { /* chunk descriptors */ > char *mr_offset; /* kva if no page, else offset */ > }; > > +#define RPCRDMA_MAX_IOVS (4) > + > struct rpcrdma_req { > - unsigned int rl_niovs; /* 0, 2 or 4 */ > - unsigned int rl_nchunks; /* non-zero if chunks */ > - unsigned int rl_connect_cookie; /* retry detection */ > - struct rpcrdma_buffer *rl_buffer; /* home base for this structure */ > + unsigned int rl_niovs; > + unsigned int rl_nchunks; > + unsigned int rl_connect_cookie; > + struct rpcrdma_buffer *rl_buffer; > struct rpcrdma_rep *rl_reply;/* holder for reply buffer */ > - struct ib_sge rl_send_iov[4]; /* for active requests */ > - struct rpcrdma_regbuf *rl_rdmabuf; > - struct rpcrdma_regbuf *rl_sendbuf; > - struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS]; > + struct ib_sge rl_send_iov[RPCRDMA_MAX_IOVS]; > + struct rpcrdma_regbuf *rl_rdmabuf; > + struct rpcrdma_regbuf *rl_sendbuf; > + struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS]; > }; > > static inline struct rpcrdma_req * > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html