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); }