From patchwork Thu Jan 14 16:22:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 12020277 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=ham 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 752B4C4332E for ; Thu, 14 Jan 2021 16:23:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5506923B3E for ; Thu, 14 Jan 2021 16:23:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727062AbhANQX2 (ORCPT ); Thu, 14 Jan 2021 11:23:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:45814 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725950AbhANQX1 (ORCPT ); Thu, 14 Jan 2021 11:23:27 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 38D0423B45; Thu, 14 Jan 2021 16:22:47 +0000 (UTC) Subject: [PATCH v1 3/5] svcrdma: Convert rdma_stat_sq_starve to a per-CPU counter From: Chuck Lever To: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org Date: Thu, 14 Jan 2021 11:22:46 -0500 Message-ID: <161064136651.6061.4240701868650517710.stgit@klimt.1015granger.net> In-Reply-To: <161064114388.6061.6808790429789225779.stgit@klimt.1015granger.net> References: <161064114388.6061.6808790429789225779.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 Avoid the overhead of a memory bus lock cycle for counting a value that is hardly every used. Signed-off-by: Chuck Lever --- include/linux/sunrpc/svc_rdma.h | 2 +- net/sunrpc/xprtrdma/svc_rdma.c | 13 +++++++++---- net/sunrpc/xprtrdma/svc_rdma_rw.c | 1 + net/sunrpc/xprtrdma/svc_rdma_sendto.c | 2 +- 4 files changed, 12 insertions(+), 6 deletions(-) diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h index ff32c59a27e7..c06b16ccf83e 100644 --- a/include/linux/sunrpc/svc_rdma.h +++ b/include/linux/sunrpc/svc_rdma.h @@ -69,7 +69,7 @@ extern unsigned int svcrdma_max_req_size; extern struct percpu_counter svcrdma_stat_recv; extern atomic_t rdma_stat_read; extern atomic_t rdma_stat_write; -extern atomic_t rdma_stat_sq_starve; +extern struct percpu_counter svcrdma_stat_sq_starve; extern atomic_t rdma_stat_rq_starve; extern atomic_t rdma_stat_rq_poll; extern atomic_t rdma_stat_rq_prod; diff --git a/net/sunrpc/xprtrdma/svc_rdma.c b/net/sunrpc/xprtrdma/svc_rdma.c index 3e5e622bad81..ee768d4c3c90 100644 --- a/net/sunrpc/xprtrdma/svc_rdma.c +++ b/net/sunrpc/xprtrdma/svc_rdma.c @@ -66,7 +66,7 @@ static unsigned int max_max_inline = RPCRDMA_MAX_INLINE_THRESH; struct percpu_counter svcrdma_stat_recv; atomic_t rdma_stat_read; atomic_t rdma_stat_write; -atomic_t rdma_stat_sq_starve; +struct percpu_counter svcrdma_stat_sq_starve; atomic_t rdma_stat_rq_starve; atomic_t rdma_stat_rq_poll; atomic_t rdma_stat_rq_prod; @@ -199,10 +199,10 @@ static struct ctl_table svcrdma_parm_table[] = { }, { .procname = "rdma_stat_sq_starve", - .data = &rdma_stat_sq_starve, - .maxlen = sizeof(atomic_t), + .data = &svcrdma_stat_sq_starve, + .maxlen = SVCRDMA_COUNTER_BUFSIZ, .mode = 0644, - .proc_handler = read_reset_stat, + .proc_handler = svcrdma_counter_handler, }, { .procname = "rdma_stat_rq_starve", @@ -267,6 +267,7 @@ static void svc_rdma_proc_cleanup(void) unregister_sysctl_table(svcrdma_table_header); svcrdma_table_header = NULL; + percpu_counter_destroy(&svcrdma_stat_sq_starve); percpu_counter_destroy(&svcrdma_stat_recv); } @@ -278,6 +279,9 @@ static int svc_rdma_proc_init(void) return 0; rc = percpu_counter_init(&svcrdma_stat_recv, 0, GFP_KERNEL); + if (rc) + goto out_err; + rc = percpu_counter_init(&svcrdma_stat_sq_starve, 0, GFP_KERNEL); if (rc) goto out_err; @@ -285,6 +289,7 @@ static int svc_rdma_proc_init(void) return 0; out_err: + percpu_counter_destroy(&svcrdma_stat_recv); return rc; } diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c index 0b63e1321d74..d7d98b2df00b 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_rw.c +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c @@ -364,6 +364,7 @@ static int svc_rdma_post_chunk_ctxt(struct svc_rdma_chunk_ctxt *cc) return 0; } + percpu_counter_inc(&svcrdma_stat_sq_starve); trace_svcrdma_sq_full(rdma); atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail); wait_event(rdma->sc_send_wait, diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c index 68af79d4f04f..52c759a8543e 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c @@ -317,7 +317,7 @@ int svc_rdma_send(struct svcxprt_rdma *rdma, struct svc_rdma_send_ctxt *ctxt) /* If the SQ is full, wait until an SQ entry is available */ while (1) { if ((atomic_dec_return(&rdma->sc_sq_avail) < 0)) { - atomic_inc(&rdma_stat_sq_starve); + percpu_counter_inc(&svcrdma_stat_sq_starve); trace_svcrdma_sq_full(rdma); atomic_inc(&rdma->sc_sq_avail); wait_event(rdma->sc_send_wait,