From patchwork Sun Jan 30 18:02:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lu X-Patchwork-Id: 12729937 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 AF4A3C433EF for ; Sun, 30 Jan 2022 18:03:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355774AbiA3SDJ (ORCPT ); Sun, 30 Jan 2022 13:03:09 -0500 Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]:57639 "EHLO out30-57.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354844AbiA3SDI (ORCPT ); Sun, 30 Jan 2022 13:03:08 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R731e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=tonylu@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0V3BCr70_1643565784; Received: from localhost(mailfrom:tonylu@linux.alibaba.com fp:SMTPD_---0V3BCr70_1643565784) by smtp.aliyun-inc.com(127.0.0.1); Mon, 31 Jan 2022 02:03:05 +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 1/3] net/smc: Send directly when TCP_CORK is cleared Date: Mon, 31 Jan 2022 02:02:55 +0800 Message-Id: <20220130180256.28303-2-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 According to the man page of TCP_CORK [1], if set, don't send out partial frames. All queued partial frames are sent when option is cleared again. When applications call setsockopt to disable TCP_CORK, this call is protected by lock_sock(), and tries to mod_delayed_work() to 0, in order to send pending data right now. However, the delayed work smc_tx_work is also protected by lock_sock(). There introduces lock contention for sending data. To fix it, send pending data directly which acts like TCP, without lock_sock() protected in the context of setsockopt (already lock_sock()ed), and cancel unnecessary dealyed work, which is protected by lock. [1] https://linux.die.net/man/7/tcp Signed-off-by: Tony Lu --- net/smc/af_smc.c | 4 ++-- net/smc/smc_tx.c | 25 +++++++++++++++---------- net/smc/smc_tx.h | 1 + 3 files changed, 18 insertions(+), 12 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index ffab9cee747d..ef021ec6b361 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -2600,8 +2600,8 @@ static int smc_setsockopt(struct socket *sock, int level, int optname, sk->sk_state != SMC_CLOSED) { if (!val) { SMC_STAT_INC(smc, cork_cnt); - mod_delayed_work(smc->conn.lgr->tx_wq, - &smc->conn.tx_work, 0); + smc_tx_pending(&smc->conn); + cancel_delayed_work(&smc->conn.tx_work); } } break; diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c index be241d53020f..7b0b6e24582f 100644 --- a/net/smc/smc_tx.c +++ b/net/smc/smc_tx.c @@ -597,27 +597,32 @@ int smc_tx_sndbuf_nonempty(struct smc_connection *conn) return rc; } -/* Wakeup sndbuf consumers from process context - * since there is more data to transmit - */ -void smc_tx_work(struct work_struct *work) +void smc_tx_pending(struct smc_connection *conn) { - struct smc_connection *conn = container_of(to_delayed_work(work), - struct smc_connection, - tx_work); struct smc_sock *smc = container_of(conn, struct smc_sock, conn); int rc; - lock_sock(&smc->sk); if (smc->sk.sk_err) - goto out; + return; rc = smc_tx_sndbuf_nonempty(conn); if (!rc && conn->local_rx_ctrl.prod_flags.write_blocked && !atomic_read(&conn->bytes_to_rcv)) conn->local_rx_ctrl.prod_flags.write_blocked = 0; +} + +/* Wakeup sndbuf consumers from process context + * since there is more data to transmit + */ +void smc_tx_work(struct work_struct *work) +{ + struct smc_connection *conn = container_of(to_delayed_work(work), + struct smc_connection, + tx_work); + struct smc_sock *smc = container_of(conn, struct smc_sock, conn); -out: + lock_sock(&smc->sk); + smc_tx_pending(conn); release_sock(&smc->sk); } diff --git a/net/smc/smc_tx.h b/net/smc/smc_tx.h index 07e6ad76224a..a59f370b8b43 100644 --- a/net/smc/smc_tx.h +++ b/net/smc/smc_tx.h @@ -27,6 +27,7 @@ static inline int smc_tx_prepared_sends(struct smc_connection *conn) return smc_curs_diff(conn->sndbuf_desc->len, &sent, &prep); } +void smc_tx_pending(struct smc_connection *conn); void smc_tx_work(struct work_struct *work); void smc_tx_init(struct smc_sock *smc); int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len); 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)) */ From patchwork Sun Jan 30 18:02:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lu X-Patchwork-Id: 12729939 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 0E4AAC433F5 for ; Sun, 30 Jan 2022 18:03:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355787AbiA3SDQ (ORCPT ); Sun, 30 Jan 2022 13:03:16 -0500 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:38818 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236867AbiA3SDM (ORCPT ); Sun, 30 Jan 2022 13:03:12 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04357;MF=tonylu@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0V3BCr7L_1643565787; Received: from localhost(mailfrom:tonylu@linux.alibaba.com fp:SMTPD_---0V3BCr7L_1643565787) by smtp.aliyun-inc.com(127.0.0.1); Mon, 31 Jan 2022 02:03:08 +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 3/3] net/smc: Cork when sendpage with MSG_SENDPAGE_NOTLAST flag Date: Mon, 31 Jan 2022 02:02:57 +0800 Message-Id: <20220130180256.28303-4-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 This introduces a new corked flag, MSG_SENDPAGE_NOTLAST, which is involved in syscall sendfile() [1], it indicates this is not the last page. So we can cork the data until the page is not specify this flag. It has the same effect as MSG_MORE, but existed in sendfile() only. This patch adds a option MSG_SENDPAGE_NOTLAST for corking data, try to cork more data before sending when using sendfile(), which acts like TCP's behaviour. Also, this reimplements the default sendpage to inform that it is supported to some extent. [1] https://man7.org/linux/man-pages/man2/sendfile.2.html Signed-off-by: Tony Lu Reviewed-by: Stefan Raspl --- net/smc/af_smc.c | 4 +++- net/smc/smc_tx.c | 19 ++++++++++++++++++- net/smc/smc_tx.h | 2 ++ 3 files changed, 23 insertions(+), 2 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index ef021ec6b361..8b78010afe01 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -2729,8 +2729,10 @@ static ssize_t smc_sendpage(struct socket *sock, struct page *page, rc = kernel_sendpage(smc->clcsock, page, offset, size, flags); } else { + lock_sock(sk); + rc = smc_tx_sendpage(smc, page, offset, size, flags); + release_sock(sk); SMC_STAT_INC(smc, sendpage_cnt); - rc = sock_no_sendpage(sock, page, offset, size, flags); } out: diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c index 9cec62cae7cb..a96ce162825e 100644 --- a/net/smc/smc_tx.c +++ b/net/smc/smc_tx.c @@ -235,7 +235,8 @@ 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)) && + if ((msg->msg_flags & MSG_MORE || smc_tx_is_corked(smc) || + msg->msg_flags & MSG_SENDPAGE_NOTLAST) && (atomic_read(&conn->sndbuf_space))) /* for a corked socket defer the RDMA writes if * sndbuf_space is still available. The applications @@ -257,6 +258,22 @@ int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len) return rc; } +int smc_tx_sendpage(struct smc_sock *smc, struct page *page, int offset, + size_t size, int flags) +{ + struct msghdr msg = {.msg_flags = flags}; + char *kaddr = kmap(page); + struct kvec iov; + int rc; + + iov.iov_base = kaddr + offset; + iov.iov_len = size; + iov_iter_kvec(&msg.msg_iter, WRITE, &iov, 1, size); + rc = smc_tx_sendmsg(smc, &msg, size); + kunmap(page); + return rc; +} + /***************************** sndbuf consumer *******************************/ /* sndbuf consumer: actual data transfer of one target chunk with ISM write */ diff --git a/net/smc/smc_tx.h b/net/smc/smc_tx.h index a59f370b8b43..34b578498b1f 100644 --- a/net/smc/smc_tx.h +++ b/net/smc/smc_tx.h @@ -31,6 +31,8 @@ void smc_tx_pending(struct smc_connection *conn); void smc_tx_work(struct work_struct *work); void smc_tx_init(struct smc_sock *smc); int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len); +int smc_tx_sendpage(struct smc_sock *smc, struct page *page, int offset, + size_t size, int flags); int smc_tx_sndbuf_nonempty(struct smc_connection *conn); void smc_tx_sndbuf_nonfull(struct smc_sock *smc); void smc_tx_consumer_update(struct smc_connection *conn, bool force);