Return-Path: Received: from mail-it0-f65.google.com ([209.85.214.65]:33330 "EHLO mail-it0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752866AbcHVS7T (ORCPT ); Mon, 22 Aug 2016 14:59:19 -0400 Subject: [PATCH v2 6/6] svcrdma: support Remote Invalidation for prototyping From: Chuck Lever To: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Mon, 22 Aug 2016 14:58:23 -0400 Message-ID: <20160822185823.12076.5952.stgit@klimt.1015granger.net> In-Reply-To: <20160822185459.12076.43516.stgit@klimt.1015granger.net> References: <20160822185459.12076.43516.stgit@klimt.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: To allow testing, add a sysctl that enables the use of Send With Invalidate in place of Send when transmitting RPC replies. The invalidate_rkey is arbitrarily chosen from among rkeys present in the RPC-over-RDMA header's chunk lists. Send With Invalidate can be enabled when all client and server HCAs support it, and the client does not send persistently registered rkeys (like a local DMA rkey). Send With Invalidate improves performance only when clients can recognize, while processing an RPC reply, that an rkey has already been invalidated. That is a separate change. In the future, the RPC-over-RDMA protocol might support Remote Invalidation properly. The protocol needs to enable signaling between peers to indicate when Remote Invalidation can be used. Signed-off-by: Chuck Lever Reviewed-by: Sagi Grimberg --- include/linux/sunrpc/svc_rdma.h | 1 + net/sunrpc/xprtrdma/svc_rdma_sendto.c | 58 ++++++++++++++++++++++++++++-- net/sunrpc/xprtrdma/svc_rdma_transport.c | 12 +++++- 3 files changed, 65 insertions(+), 6 deletions(-) diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h index 3584bc8..cc3ae16 100644 --- a/include/linux/sunrpc/svc_rdma.h +++ b/include/linux/sunrpc/svc_rdma.h @@ -137,6 +137,7 @@ struct svcxprt_rdma { int sc_ord; /* RDMA read limit */ int sc_max_sge; int sc_max_sge_rd; /* max sge for read target */ + bool sc_snd_w_inv; /* OK to use Send With Invalidate */ atomic_t sc_sq_count; /* Number of SQ WR on queue */ unsigned int sc_sq_depth; /* Depth of SQ */ diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c index 3b95b19..f5a91ed 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c @@ -225,6 +225,48 @@ svc_rdma_get_reply_array(struct rpcrdma_msg *rmsgp, return rp_ary; } +/* RPC-over-RDMA Version One private extension: Remote Invalidation. + * Responder's choice: requester signals it can handle Send With + * Invalidate, and responder chooses one rkey to invalidate. + * + * Find a candidate rkey to invalidate when sending a reply. Picks the + * first rkey it finds in the chunks lists. + * + * Returns zero if RPC's chunk lists are empty. + */ +static u32 svc_rdma_get_inv_rkey(struct rpcrdma_msg *rdma_argp, + struct rpcrdma_write_array *wr_ary, + struct rpcrdma_write_array *rp_ary) +{ + struct rpcrdma_read_chunk *rd_ary; + struct rpcrdma_segment *arg_ch; + u32 inv_rkey; + + inv_rkey = 0; + + rd_ary = svc_rdma_get_read_chunk(rdma_argp); + if (rd_ary) { + inv_rkey = be32_to_cpu(rd_ary->rc_target.rs_handle); + goto out; + } + + if (wr_ary && be32_to_cpu(wr_ary->wc_nchunks)) { + arg_ch = &wr_ary->wc_array[0].wc_target; + inv_rkey = be32_to_cpu(arg_ch->rs_handle); + goto out; + } + + if (rp_ary && be32_to_cpu(rp_ary->wc_nchunks)) { + arg_ch = &rp_ary->wc_array[0].wc_target; + inv_rkey = be32_to_cpu(arg_ch->rs_handle); + goto out; + } + +out: + dprintk("svcrdma: Send With Invalidate rkey=%08x\n", inv_rkey); + return inv_rkey; +} + /* Assumptions: * - The specified write_len can be represented in sc_max_sge * PAGE_SIZE */ @@ -464,7 +506,8 @@ static int send_reply(struct svcxprt_rdma *rdma, struct page *page, struct rpcrdma_msg *rdma_resp, struct svc_rdma_req_map *vec, - int byte_count) + int byte_count, + u32 inv_rkey) { struct svc_rdma_op_ctxt *ctxt; struct ib_send_wr send_wr; @@ -535,7 +578,11 @@ static int send_reply(struct svcxprt_rdma *rdma, send_wr.wr_cqe = &ctxt->cqe; send_wr.sg_list = ctxt->sge; send_wr.num_sge = sge_no; - send_wr.opcode = IB_WR_SEND; + if (inv_rkey) { + send_wr.opcode = IB_WR_SEND_WITH_INV; + send_wr.ex.invalidate_rkey = inv_rkey; + } else + send_wr.opcode = IB_WR_SEND; send_wr.send_flags = IB_SEND_SIGNALED; ret = svc_rdma_send(rdma, &send_wr); @@ -567,6 +614,7 @@ int svc_rdma_sendto(struct svc_rqst *rqstp) int inline_bytes; struct page *res_page; struct svc_rdma_req_map *vec; + u32 inv_rkey; dprintk("svcrdma: sending response for rqstp=%p\n", rqstp); @@ -577,6 +625,10 @@ int svc_rdma_sendto(struct svc_rqst *rqstp) wr_ary = svc_rdma_get_write_array(rdma_argp); rp_ary = svc_rdma_get_reply_array(rdma_argp, wr_ary); + inv_rkey = 0; + if (rdma->sc_snd_w_inv) + inv_rkey = svc_rdma_get_inv_rkey(rdma_argp, wr_ary, rp_ary); + /* Build an req vec for the XDR */ vec = svc_rdma_get_req_map(rdma); ret = svc_rdma_map_xdr(rdma, &rqstp->rq_res, vec, wr_ary != NULL); @@ -619,7 +671,7 @@ int svc_rdma_sendto(struct svc_rqst *rqstp) goto err1; ret = send_reply(rdma, rqstp, res_page, rdma_resp, vec, - inline_bytes); + inline_bytes, inv_rkey); if (ret < 0) goto err0; diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c index f51e98a..b2464fc 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c @@ -657,9 +657,14 @@ svc_rdma_parse_connect_private(struct svcxprt_rdma *newxprt, if (pmsg && pmsg->cp_magic == rpcrdma_cmp_magic && pmsg->cp_version == RPCRDMA_CMP_VERSION) { - dprintk("svcrdma: client send_size %u, recv_size %u\n", + newxprt->sc_snd_w_inv = pmsg->cp_flags & + RPCRDMA_CMP_F_SND_W_INV_OK; + + dprintk("svcrdma: client send_size %u, recv_size %u " + "remote inv %ssupported\n", rpcrdma_decode_buffer_size(pmsg->cp_send_size), - rpcrdma_decode_buffer_size(pmsg->cp_recv_size)); + rpcrdma_decode_buffer_size(pmsg->cp_recv_size), + newxprt->sc_snd_w_inv ? "" : "un"); } } @@ -1093,7 +1098,8 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt) dev->attrs.max_fast_reg_page_list_len; newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_FAST_REG; newxprt->sc_reader = rdma_read_chunk_frmr; - } + } else + newxprt->sc_snd_w_inv = false; /* * Determine if a DMA MR is required and if so, what privs are required