From patchwork Thu Jan 21 20:53:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever III X-Patchwork-Id: 12037803 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4ADDFC433DB for ; Thu, 21 Jan 2021 21:19:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1979C22BEF for ; Thu, 21 Jan 2021 21:19:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727206AbhAUVSl (ORCPT ); Thu, 21 Jan 2021 16:18:41 -0500 Received: from mail.kernel.org ([198.145.29.99]:32864 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727104AbhAUUyt (ORCPT ); Thu, 21 Jan 2021 15:54:49 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0834323A5E; Thu, 21 Jan 2021 20:53:06 +0000 (UTC) Subject: [PATCH v1 1/2] svcrdma: Reduce Receive doorbell rate From: Chuck Lever To: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org Date: Thu, 21 Jan 2021 15:53:06 -0500 Message-ID: <161126238612.8979.2073990353982116611.stgit@klimt.1015granger.net> In-Reply-To: <161126216710.8979.7145432546367265892.stgit@klimt.1015granger.net> References: <161126216710.8979.7145432546367265892.stgit@klimt.1015granger.net> User-Agent: StGit/0.23-29-ga622f1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org This is similar to commit e340c2d6ef2a ("xprtrdma: Reduce the doorbell rate (Receive)") which added Receive batching to the client. Signed-off-by: Chuck Lever --- include/linux/sunrpc/svc_rdma.h | 1 net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 82 ++++++++++++++++--------------- 2 files changed, 44 insertions(+), 39 deletions(-) diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h index 1e76ed688044..7c693b31965e 100644 --- a/include/linux/sunrpc/svc_rdma.h +++ b/include/linux/sunrpc/svc_rdma.h @@ -104,6 +104,7 @@ struct svcxprt_rdma { wait_queue_head_t sc_send_wait; /* SQ exhaustion waitlist */ unsigned long sc_flags; + u32 sc_pending_recvs; struct list_head sc_read_complete_q; struct work_struct sc_work; diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c index 7d14a74df716..ab0b7e9777bc 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -266,33 +266,46 @@ void svc_rdma_release_rqst(struct svc_rqst *rqstp) svc_rdma_recv_ctxt_put(rdma, ctxt); } -static int __svc_rdma_post_recv(struct svcxprt_rdma *rdma, - struct svc_rdma_recv_ctxt *ctxt) +static bool svc_rdma_refresh_recvs(struct svcxprt_rdma *rdma, + unsigned int wanted, bool temp) { + const struct ib_recv_wr *bad_wr = NULL; + struct svc_rdma_recv_ctxt *ctxt; + struct ib_recv_wr *recv_chain; int ret; - trace_svcrdma_post_recv(ctxt); - ret = ib_post_recv(rdma->sc_qp, &ctxt->rc_recv_wr, NULL); + recv_chain = NULL; + while (wanted--) { + ctxt = svc_rdma_recv_ctxt_get(rdma); + if (!ctxt) + break; + + trace_svcrdma_post_recv(ctxt); + ctxt->rc_temp = temp; + ctxt->rc_recv_wr.next = recv_chain; + recv_chain = &ctxt->rc_recv_wr; + rdma->sc_pending_recvs++; + } + if (!recv_chain) + return false; + + ret = ib_post_recv(rdma->sc_qp, recv_chain, &bad_wr); if (ret) goto err_post; - return 0; + return true; err_post: - trace_svcrdma_rq_post_err(rdma, ret); - svc_rdma_recv_ctxt_put(rdma, ctxt); - return ret; -} - -static int svc_rdma_post_recv(struct svcxprt_rdma *rdma) -{ - struct svc_rdma_recv_ctxt *ctxt; + while (bad_wr) { + ctxt = container_of(bad_wr, struct svc_rdma_recv_ctxt, + rc_recv_wr); + bad_wr = bad_wr->next; + svc_rdma_recv_ctxt_put(rdma, ctxt); + } - if (test_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags)) - return 0; - ctxt = svc_rdma_recv_ctxt_get(rdma); - if (!ctxt) - return -ENOMEM; - return __svc_rdma_post_recv(rdma, ctxt); + trace_svcrdma_rq_post_err(rdma, ret); + /* Since we're destroying the xprt, no need to reset + * sc_pending_recvs. */ + return false; } /** @@ -303,20 +316,7 @@ static int svc_rdma_post_recv(struct svcxprt_rdma *rdma) */ bool svc_rdma_post_recvs(struct svcxprt_rdma *rdma) { - struct svc_rdma_recv_ctxt *ctxt; - unsigned int i; - int ret; - - for (i = 0; i < rdma->sc_max_requests; i++) { - ctxt = svc_rdma_recv_ctxt_get(rdma); - if (!ctxt) - return false; - ctxt->rc_temp = true; - ret = __svc_rdma_post_recv(rdma, ctxt); - if (ret) - return false; - } - return true; + return svc_rdma_refresh_recvs(rdma, rdma->sc_max_requests, true); } /** @@ -324,8 +324,6 @@ bool svc_rdma_post_recvs(struct svcxprt_rdma *rdma) * @cq: Completion Queue context * @wc: Work Completion object * - * NB: The svc_xprt/svcxprt_rdma is pinned whenever it's possible that - * the Receive completion handler could be running. */ static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc) { @@ -333,6 +331,8 @@ static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc) struct ib_cqe *cqe = wc->wr_cqe; struct svc_rdma_recv_ctxt *ctxt; + rdma->sc_pending_recvs--; + /* WARNING: Only wc->wr_cqe and wc->status are reliable */ ctxt = container_of(cqe, struct svc_rdma_recv_ctxt, rc_cqe); @@ -340,9 +340,6 @@ static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc) if (wc->status != IB_WC_SUCCESS) goto flushed; - if (svc_rdma_post_recv(rdma)) - goto post_err; - /* All wc fields are now known to be valid */ ctxt->rc_byte_len = wc->byte_len; ib_dma_sync_single_for_cpu(rdma->sc_pd->device, @@ -356,11 +353,18 @@ static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc) spin_unlock(&rdma->sc_rq_dto_lock); if (!test_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags)) svc_xprt_enqueue(&rdma->sc_xprt); + + if (!test_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags) && + rdma->sc_pending_recvs < rdma->sc_max_requests) + if (!svc_rdma_refresh_recvs(rdma, RPCRDMA_MAX_RECV_BATCH, + false)) + goto post_err; + return; flushed: -post_err: svc_rdma_recv_ctxt_put(rdma, ctxt); +post_err: set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags); svc_xprt_enqueue(&rdma->sc_xprt); } From patchwork Thu Jan 21 20:53:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever III X-Patchwork-Id: 12037805 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49493C433DB for ; Thu, 21 Jan 2021 21:19:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 09E3323A53 for ; Thu, 21 Jan 2021 21:19:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726727AbhAUVSi (ORCPT ); Thu, 21 Jan 2021 16:18:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:32884 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726567AbhAUUyt (ORCPT ); Thu, 21 Jan 2021 15:54:49 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3D24523A5D; Thu, 21 Jan 2021 20:53:13 +0000 (UTC) Subject: [PATCH v1 2/2] svcrdma: DMA-sync the receive buffer in svc_rdma_recvfrom() From: Chuck Lever To: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org Date: Thu, 21 Jan 2021 15:53:12 -0500 Message-ID: <161126239239.8979.7995314438640511469.stgit@klimt.1015granger.net> In-Reply-To: <161126216710.8979.7145432546367265892.stgit@klimt.1015granger.net> References: <161126216710.8979.7145432546367265892.stgit@klimt.1015granger.net> User-Agent: StGit/0.23-29-ga622f1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org The Receive completion handler doesn't look at the contents of the Receive buffer. The DMA sync isn't terribly expensive but it's one less thing that needs to be done by the Receive completion handler, which is single-threaded (per svc_xprt). This helps scalability. Signed-off-by: Chuck Lever Reviewed-by: Christoph Hellwig --- net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c index ab0b7e9777bc..6d28f23ceb35 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -342,9 +342,6 @@ static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc) /* All wc fields are now known to be valid */ ctxt->rc_byte_len = wc->byte_len; - ib_dma_sync_single_for_cpu(rdma->sc_pd->device, - ctxt->rc_recv_sge.addr, - wc->byte_len, DMA_FROM_DEVICE); spin_lock(&rdma->sc_rq_dto_lock); list_add_tail(&ctxt->rc_list, &rdma->sc_rq_dto_q); @@ -851,6 +848,9 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp) spin_unlock(&rdma_xprt->sc_rq_dto_lock); percpu_counter_inc(&svcrdma_stat_recv); + ib_dma_sync_single_for_cpu(rdma_xprt->sc_pd->device, + ctxt->rc_recv_sge.addr, ctxt->rc_byte_len, + DMA_FROM_DEVICE); svc_rdma_build_arg_xdr(rqstp, ctxt); /* Prevent svc_xprt_release from releasing pages in rq_pages