From mboxrd@z Thu Jan 1 00:00:00 1970 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 10BABECAAA1 for ; Tue, 6 Sep 2022 16:46:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237787AbiIFQqq (ORCPT ); Tue, 6 Sep 2022 12:46:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237863AbiIFQqJ (ORCPT ); Tue, 6 Sep 2022 12:46:09 -0400 Received: from smtp-fw-2101.amazon.com (smtp-fw-2101.amazon.com [72.21.196.25]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 512DC7E038 for ; Tue, 6 Sep 2022 09:26:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1662481601; x=1694017601; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=TGql0ulHvhFhJoDQvwTVLhNx/rVZJi1wzTK0B8Ok6IE=; b=SM1wWBUV3pJovtk36M6aJTyQbpuimibqW5Zpl0E7gALM2ZF44KWWI21O sTD+7sRRmm6Z8mOhy9+d1UMwTUwP3z46JcoZnNYyJIwkHp8FlxIRTLWB1 iGgz6rAjKJciYoF3kDccREHSXDAi1rbGmKNTPY8soPi+eBsRyG+ogaWTw 4=; X-IronPort-AV: E=Sophos;i="5.93,294,1654560000"; d="scan'208";a="238170067" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-pdx-2c-7d0c7241.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-2101.iad2.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Sep 2022 16:26:27 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-pdx-2c-7d0c7241.us-west-2.amazon.com (Postfix) with ESMTPS id 6169445108; Tue, 6 Sep 2022 16:26:26 +0000 (UTC) Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX13MTAUWB001.ant.amazon.com (10.43.161.249) with Microsoft SMTP Server (TLS) id 15.0.1497.38; Tue, 6 Sep 2022 16:26:25 +0000 Received: from 88665a182662.ant.amazon.com (10.43.161.172) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1118.12; Tue, 6 Sep 2022 16:26:23 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni CC: Kuniyuki Iwashima , Kuniyuki Iwashima , Subject: [PATCH v4 net-next 5/6] tcp: Save unnecessary inet_twsk_purge() calls. Date: Tue, 6 Sep 2022 09:24:22 -0700 Message-ID: <20220906162423.44410-6-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220906162423.44410-1-kuniyu@amazon.com> References: <20220906162423.44410-1-kuniyu@amazon.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.43.161.172] X-ClientProxiedBy: EX13D30UWC002.ant.amazon.com (10.43.162.235) To EX19D004ANA001.ant.amazon.com (10.37.240.138) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org While destroying netns, we call inet_twsk_purge() in tcp_sk_exit_batch() and tcpv6_net_exit_batch() for AF_INET and AF_INET6. These commands trigger the kernel to walk through the potentially big ehash twice even though the netns has no TIME_WAIT sockets. # ip netns add test # ip netns del test or # unshare -n /bin/true >/dev/null When tw_refcount is 0, we need not call inet_twsk_purge() at least for the net. We can save such unneeded iterations if all netns in net_exit_list have no TIME_WAIT sockets. This change eliminates the tax by the additional unshare() described in the next patch to guarantee the per-netns ehash size. Tested: # mount -t debugfs none /sys/kernel/debug/ # echo cleanup_net > /sys/kernel/debug/tracing/set_ftrace_filter # echo inet_twsk_purge >> /sys/kernel/debug/tracing/set_ftrace_filter # echo function > /sys/kernel/debug/tracing/current_tracer # cat ./add_del_unshare.sh for i in `seq 1 40` do (for j in `seq 1 100` ; do unshare -n /bin/true >/dev/null ; done) & done wait; # ./add_del_unshare.sh Before the patch: # cat /sys/kernel/debug/tracing/trace_pipe kworker/u128:0-8 [031] ...1. 174.162765: cleanup_net <-process_one_work kworker/u128:0-8 [031] ...1. 174.240796: inet_twsk_purge <-cleanup_net kworker/u128:0-8 [032] ...1. 174.244759: inet_twsk_purge <-tcp_sk_exit_batch kworker/u128:0-8 [034] ...1. 174.290861: cleanup_net <-process_one_work kworker/u128:0-8 [039] ...1. 175.245027: inet_twsk_purge <-cleanup_net kworker/u128:0-8 [046] ...1. 175.290541: inet_twsk_purge <-tcp_sk_exit_batch kworker/u128:0-8 [037] ...1. 175.321046: cleanup_net <-process_one_work kworker/u128:0-8 [024] ...1. 175.941633: inet_twsk_purge <-cleanup_net kworker/u128:0-8 [025] ...1. 176.242539: inet_twsk_purge <-tcp_sk_exit_batch After: # cat /sys/kernel/debug/tracing/trace_pipe kworker/u128:0-8 [038] ...1. 428.116174: cleanup_net <-process_one_work kworker/u128:0-8 [038] ...1. 428.262532: cleanup_net <-process_one_work kworker/u128:0-8 [030] ...1. 429.292645: cleanup_net <-process_one_work Signed-off-by: Kuniyuki Iwashima --- include/net/tcp.h | 1 + net/ipv4/tcp_ipv4.c | 2 +- net/ipv4/tcp_minisocks.c | 14 ++++++++++++++ net/ipv6/tcp_ipv6.c | 2 +- 4 files changed, 17 insertions(+), 2 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index d10962b9f0d0..f60996c1d7b3 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -346,6 +346,7 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb); void tcp_rcv_space_adjust(struct sock *sk); int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); void tcp_twsk_destructor(struct sock *sk); +void tcp_twsk_purge(struct list_head *net_exit_list, int family); ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, struct pipe_inode_info *pipe, size_t len, unsigned int flags); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 395e7b82b700..531b833a8056 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -3205,7 +3205,7 @@ static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list) { struct net *net; - inet_twsk_purge(&tcp_hashinfo, AF_INET); + tcp_twsk_purge(net_exit_list, AF_INET); list_for_each_entry(net, net_exit_list, exit_list) tcp_fastopen_ctx_destroy(net); diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 2e53981252d9..10d84a854e4d 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -347,6 +347,20 @@ void tcp_twsk_destructor(struct sock *sk) } EXPORT_SYMBOL_GPL(tcp_twsk_destructor); +void tcp_twsk_purge(struct list_head *net_exit_list, int family) +{ + struct net *net; + + list_for_each_entry(net, net_exit_list, exit_list) { + if (!refcount_read(&net->ipv4.tcp_death_row.tw_refcount)) + continue; + + inet_twsk_purge(&tcp_hashinfo, family); + break; + } +} +EXPORT_SYMBOL_GPL(tcp_twsk_purge); + /* Warning : This function is called without sk_listener being locked. * Be sure to read socket fields once, as their value could change under us. */ diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index f9ed47eb9b93..06beed4e23bf 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -2229,7 +2229,7 @@ static void __net_exit tcpv6_net_exit(struct net *net) static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list) { - inet_twsk_purge(&tcp_hashinfo, AF_INET6); + tcp_twsk_purge(net_exit_list, AF_INET6); } static struct pernet_operations tcpv6_net_ops = { -- 2.30.2