From patchwork Fri May 24 17:37:59 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 246254 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 17F4E2C0098 for ; Sat, 25 May 2013 03:38:46 +1000 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1Ufvws-00004q-Od; Fri, 24 May 2013 17:38:38 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1UfvwH-0008FH-Pw for kernel-team@lists.ubuntu.com; Fri, 24 May 2013 17:38:01 +0000 Received: from c-67-160-231-42.hsd1.ca.comcast.net ([67.160.231.42] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1UfvwH-0003VP-EX; Fri, 24 May 2013 17:38:01 +0000 Received: from kamal by fourier with local (Exim 4.80) (envelope-from ) id 1UfvwF-0002I1-B7; Fri, 24 May 2013 10:37:59 -0700 From: Kamal Mostafa To: Yuchung Cheng Subject: [ 3.8.y.z extended stable ] Patch "tcp: reset timer after any SYNACK retransmit" has been added to staging queue Date: Fri, 24 May 2013 10:37:59 -0700 Message-Id: <1369417079-8771-1-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 X-Extended-Stable: 3.8 Cc: Kamal Mostafa , Eric Dumazet , Neal Cardwell , "David S. Miller" , kernel-team@lists.ubuntu.com X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled tcp: reset timer after any SYNACK retransmit to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From c6bb76b5e686b95ea8c9559dc612e0a1c2836582 Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Mon, 29 Apr 2013 08:44:51 +0000 Subject: tcp: reset timer after any SYNACK retransmit [ Upstream commit cd75eff64dae8856afbf6ef0f0ca3c145465d8e0 ] Linux immediately returns SYNACK on (spurious) SYN retransmits, but keeps the SYNACK timer running independently. Thus the timer may fire right after the SYNACK retransmit and causes a SYN-SYNACK cross-fire burst. Adopt the fast retransmit/recovery idea in established state by re-arming the SYNACK timer after the fast (SYNACK) retransmit. The timer may fire late up to 500ms due to the current SYNACK timer wheel, but it's OK to be conservative when network is congested. Eric's new listener design should address this issue. Signed-off-by: Yuchung Cheng Acked-by: Eric Dumazet Acked-by: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- net/ipv4/tcp_minisocks.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) -- 1.8.1.2 diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index f35f2df..18e230d 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -581,8 +581,13 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, * * Note that even if there is new data in the SYN packet * they will be thrown away too. + * + * Reset timer after retransmitting SYNACK, similar to + * the idea of fast retransmit in recovery. */ - inet_rtx_syn_ack(sk, req); + if (!inet_rtx_syn_ack(sk, req)) + req->expires = min(TCP_TIMEOUT_INIT << req->num_timeout, + TCP_RTO_MAX) + jiffies; return NULL; }