From patchwork Sun Jan 30 18:02:56 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lu X-Patchwork-Id: 12729938 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E019EC433F5 for ; Sun, 30 Jan 2022 18:03:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355780AbiA3SDL (ORCPT ); Sun, 30 Jan 2022 13:03:11 -0500 Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]:35463 "EHLO out30-57.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236867AbiA3SDI (ORCPT ); Sun, 30 Jan 2022 13:03:08 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R721e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04407;MF=tonylu@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0V3BCr7A_1643565786; Received: from localhost(mailfrom:tonylu@linux.alibaba.com fp:SMTPD_---0V3BCr7A_1643565786) by smtp.aliyun-inc.com(127.0.0.1); Mon, 31 Jan 2022 02:03:07 +0800 From: Tony Lu To: kgraul@linux.ibm.com, kuba@kernel.org, davem@davemloft.net Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org Subject: [PATCH net-next 2/3] net/smc: Remove corked dealyed work Date: Mon, 31 Jan 2022 02:02:56 +0800 Message-Id: <20220130180256.28303-3-tonylu@linux.alibaba.com> X-Mailer: git-send-email 2.35.0 In-Reply-To: <20220130180256.28303-1-tonylu@linux.alibaba.com> References: <20220130180256.28303-1-tonylu@linux.alibaba.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Based on the manual of TCP_CORK [1] and MSG_MORE [2], these two options have the same effect. Applications can set these options and informs the kernel to pend the data, and send them out only when the socket or syscall does not specify this flag. In other words, there's no need to send data out by a delayed work, which will queue a lot of work. This removes corked delayed work with SMC_TX_CORK_DELAY (250ms), and the applications control how/when to send them out. It improves the performance for sendfile and throughput, and remove unnecessary race of lock_sock(). This also unlocks the limitation of sndbuf, and try to fill it up before sending. [1] https://linux.die.net/man/7/tcp [2] https://man7.org/linux/man-pages/man2/send.2.html Signed-off-by: Tony Lu --- net/smc/smc_tx.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c index 7b0b6e24582f..9cec62cae7cb 100644 --- a/net/smc/smc_tx.c +++ b/net/smc/smc_tx.c @@ -31,7 +31,6 @@ #include "smc_tracepoint.h" #define SMC_TX_WORK_DELAY 0 -#define SMC_TX_CORK_DELAY (HZ >> 2) /* 250 ms */ /***************************** sndbuf producer *******************************/ @@ -237,15 +236,13 @@ int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len) if ((msg->msg_flags & MSG_OOB) && !send_remaining) conn->urg_tx_pend = true; if ((msg->msg_flags & MSG_MORE || smc_tx_is_corked(smc)) && - (atomic_read(&conn->sndbuf_space) > - (conn->sndbuf_desc->len >> 1))) - /* for a corked socket defer the RDMA writes if there - * is still sufficient sndbuf_space available + (atomic_read(&conn->sndbuf_space))) + /* for a corked socket defer the RDMA writes if + * sndbuf_space is still available. The applications + * should known how/when to uncork it. */ - queue_delayed_work(conn->lgr->tx_wq, &conn->tx_work, - SMC_TX_CORK_DELAY); - else - smc_tx_sndbuf_nonempty(conn); + continue; + smc_tx_sndbuf_nonempty(conn); trace_smc_tx_sendmsg(smc, copylen); } /* while (msg_data_left(msg)) */