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 A2CC9ECAAD2 for ; Mon, 29 Aug 2022 16:21:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230271AbiH2QVp (ORCPT ); Mon, 29 Aug 2022 12:21:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50252 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230429AbiH2QVT (ORCPT ); Mon, 29 Aug 2022 12:21:19 -0400 Received: from smtp-fw-80006.amazon.com (smtp-fw-80006.amazon.com [99.78.197.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5803C14084 for ; Mon, 29 Aug 2022 09:21:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1661790079; x=1693326079; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Y9d1dM5ocX1U70fsqGIsuhQ18QoRy3fY+UJZ18+a8mw=; b=PSCElLvNoKFBZ2iilc3mdc1u7sUvTqzskNhYa9t7oOJedhtGZg/v4M9k w/fLm/3eLDs0ZJsax3yviuPiNxm2+IgBKQJeYXp1mH37uJTqe7ATA8ksv O21YOzGPpLFJPx+uVi+UK98tjdJGQGlzXxowVN8NolddwLc+95pKO1GRD Y=; X-IronPort-AV: E=Sophos;i="5.93,272,1654560000"; d="scan'208";a="124414213" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO email-inbound-relay-pdx-2b-718d0906.us-west-2.amazon.com) ([10.25.36.210]) by smtp-border-fw-80006.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Aug 2022 16:20:36 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan2.pdx.amazon.com [10.236.137.194]) by email-inbound-relay-pdx-2b-718d0906.us-west-2.amazon.com (Postfix) with ESMTPS id 3513C3E0267; Mon, 29 Aug 2022 16:20:35 +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; Mon, 29 Aug 2022 16:20:34 +0000 Received: from 88665a182662.ant.amazon.com.com (10.43.162.158) 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; Mon, 29 Aug 2022 16:20:32 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni CC: Kuniyuki Iwashima , Kuniyuki Iwashima , Subject: [PATCH v2 net-next 4/5] tcp: Save unnecessary inet_twsk_purge() calls. Date: Mon, 29 Aug 2022 09:19:19 -0700 Message-ID: <20220829161920.99409-5-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220829161920.99409-1-kuniyu@amazon.com> References: <20220829161920.99409-1-kuniyu@amazon.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.43.162.158] X-ClientProxiedBy: EX13D02UWB002.ant.amazon.com (10.43.161.160) 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 AF_INET6 uses module_init() to be loaded after AF_INET which uses fs_initcall(), so tcpv6_net_ops is always registered after tcp_sk_ops. Also, we clean up netns in the reverse order, so tcpv6_net_exit_batch() is always called before tcp_sk_exit_batch(). The characteristic enables us to save such unneeded iterations. This change eliminates the tax by the additional unshare() described in the next patch to guarantee the per-netns ehash size. Signed-off-by: Kuniyuki Iwashima --- include/net/tcp.h | 1 + net/ipv4/tcp_ipv4.c | 6 ++++-- net/ipv4/tcp_minisocks.c | 24 ++++++++++++++++++++++++ net/ipv6/tcp_ipv6.c | 2 +- 4 files changed, 30 insertions(+), 3 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 b07930643b11..f4a502d57d45 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -3109,8 +3109,10 @@ static void __net_exit tcp_sk_exit(struct net *net) if (net->ipv4.tcp_congestion_control) bpf_module_put(net->ipv4.tcp_congestion_control, net->ipv4.tcp_congestion_control->owner); - if (refcount_dec_and_test(&tcp_death_row->tw_refcount)) + if (refcount_dec_and_test(&tcp_death_row->tw_refcount)) { kfree(tcp_death_row); + net->ipv4.tcp_death_row = NULL; + } } static int __net_init tcp_sk_init(struct net *net) @@ -3210,7 +3212,7 @@ 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 361aad67c6d6..9168c5a33344 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -347,6 +347,30 @@ 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 (!net->ipv4.tcp_death_row) + continue; + + /* AF_INET6 using module_init() is always registered after + * AF_INET using fs_initcall() and cleaned up in the reverse + * order. + * + * The last refcount is decremented later in tcp_sk_exit(). + */ + if (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6 && + refcount_read(&net->ipv4.tcp_death_row->tw_refcount) == 1) + 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 27b2fd98a2c4..9cbc7f0d7149 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