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 X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 4294FC433FE for ; Mon, 7 Dec 2020 11:47:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED2B023340 for ; Mon, 7 Dec 2020 11:47:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726912AbgLGLrs (ORCPT ); Mon, 7 Dec 2020 06:47:48 -0500 Received: from smtp-fw-2101.amazon.com ([72.21.196.25]:4564 "EHLO smtp-fw-2101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726874AbgLGLrs (ORCPT ); Mon, 7 Dec 2020 06:47:48 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1607341668; x=1638877668; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=DT8dfGvHCH2RcZ5XMyxNuf8g5vxxb2qMyJp3K1JoGJg=; b=o6Ucx1C/WbtLHxBaCKtQfqSPNPQA9CioGsYJZ69uG3mCFVXpPDIOSAPY VsXBuHrfEr8SVJQc+2GI/vrh8NHY3fMD3+Tsy3hu/qfnil13QRTMU3784 cykhbpUH4HaQ3JNYu1I0iJjF+/ZlilzQZsiv4l2aOR4u5WgCZbST/owFw I=; X-IronPort-AV: E=Sophos;i="5.78,399,1599523200"; d="scan'208";a="67686016" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-1e-42f764a0.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-2101.iad2.amazon.com with ESMTP; 07 Dec 2020 11:47:00 +0000 Received: from EX13MTAUWC001.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan2.iad.amazon.com [10.40.163.34]) by email-inbound-relay-1e-42f764a0.us-east-1.amazon.com (Postfix) with ESMTPS id E815AC1E3E; Mon, 7 Dec 2020 11:46:58 +0000 (UTC) Received: from EX13D35UWC003.ant.amazon.com (10.43.162.130) by EX13MTAUWC001.ant.amazon.com (10.43.162.135) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 7 Dec 2020 11:46:58 +0000 Received: from EX13MTAUWC001.ant.amazon.com (10.43.162.135) by EX13D35UWC003.ant.amazon.com (10.43.162.130) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 7 Dec 2020 11:46:58 +0000 Received: from dev-dsk-abuehaze-1c-926c8132.eu-west-1.amazon.com (10.15.10.116) by mail-relay.amazon.com (10.43.162.232) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Mon, 7 Dec 2020 11:46:57 +0000 Received: by dev-dsk-abuehaze-1c-926c8132.eu-west-1.amazon.com (Postfix, from userid 5005603) id 67F518846F; Mon, 7 Dec 2020 11:46:57 +0000 (UTC) From: Hazem Mohamed Abuelfotoh To: CC: , , , , , , , Hazem Mohamed Abuelfotoh Subject: [PATCH net] tcp: fix receive buffer autotuning to trigger for any valid advertised MSS Date: Mon, 7 Dec 2020 11:46:25 +0000 Message-ID: <20201207114625.9079-1-abuehaze@amazon.com> X-Mailer: git-send-email 2.16.6 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Previously receiver buffer auto-tuning starts after receiving one advertised window amount of data.After the initial receiver buffer was raised by commit a337531b942b ("tcp: up initial rmem to 128KB and SYN rwin to around 64KB"),the receiver buffer may take too long for TCP autotuning to start raising the receiver buffer size. commit 041a14d26715 ("tcp: start receiver buffer autotuning sooner") tried to decrease the threshold at which TCP auto-tuning starts but it's doesn't work well in some environments where the receiver has large MTU (9001) especially with high RTT connections as in these environments rcvq_space.space will be the same as rcv_wnd so TCP autotuning will never start because sender can't send more than rcv_wnd size in one round trip. To address this issue this patch is decreasing the initial rcvq_space.space so TCP autotuning kicks in whenever the sender is able to send more than 5360 bytes in one round trip regardless the receiver's configured MTU. Fixes: a337531b942b ("tcp: up initial rmem to 128KB and SYN rwin to around 64KB") Fixes: 041a14d26715 ("tcp: start receiver buffer autotuning sooner") Signed-off-by: Hazem Mohamed Abuelfotoh --- net/ipv4/tcp_input.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 389d1b340248..f0ffac9e937b 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -504,13 +504,14 @@ static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb) static void tcp_init_buffer_space(struct sock *sk) { int tcp_app_win = sock_net(sk)->ipv4.sysctl_tcp_app_win; + struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); int maxwin; if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) tcp_sndbuf_expand(sk); - tp->rcvq_space.space = min_t(u32, tp->rcv_wnd, TCP_INIT_CWND * tp->advmss); + tp->rcvq_space.space = min_t(u32, tp->rcv_wnd, TCP_INIT_CWND * icsk->icsk_ack.rcv_mss); tcp_mstamp_refresh(tp); tp->rcvq_space.time = tp->tcp_mstamp; tp->rcvq_space.seq = tp->copied_seq; -- 2.16.6 Amazon Web Services EMEA SARL, 38 avenue John F. Kennedy, L-1855 Luxembourg, R.C.S. Luxembourg B186284 Amazon Web Services EMEA SARL, Irish Branch, One Burlington Plaza, Burlington Road, Dublin 4, Ireland, branch registration number 908705