From patchwork Thu Mar 11 20:35:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 12132911 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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 DEC33C433E9 for ; Thu, 11 Mar 2021 20:36:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B99164F91 for ; Thu, 11 Mar 2021 20:36:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231244AbhCKUgN (ORCPT ); Thu, 11 Mar 2021 15:36:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230516AbhCKUfz (ORCPT ); Thu, 11 Mar 2021 15:35:55 -0500 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4B9AC061574 for ; Thu, 11 Mar 2021 12:35:55 -0800 (PST) Received: by mail-pj1-x1034.google.com with SMTP id cl21-20020a17090af695b02900c61ac0f0e9so3747881pjb.1 for ; Thu, 11 Mar 2021 12:35:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=h8XVbQKdXCWJQp+umGqqBJDYSqgM/CA/nG8vr+0C1eI=; b=n/cnfUpru2OKNmHrzw+FfXNRavHTpJBic0/dX96BvTsAR/QF2/GBX4PVb0s7uHiGhj GuKmhjDZcYfReQcydiNpHw9pKJ3xLKDJTfONsu7afATM/aeyR//WoXQtGqxg3UDgIiHX bI6a0TIpjsSLPGUKndpvebCURwcQPs28gBFWD9Vuih4UUFY4qt72qWBVsQdQm4PPmOjz 1SlFRHdtZpIIkgxekSPJFOfLYbCXaF/MYd96Kxk+Py3gbfJ3l17SjM1f2SScMyhqiRxx E1Pm9Z3810WRrp8gpcUcoRdGi2OhXimEOlv0guUm3gMn3U8omhTEsB3hHxy+p7784hfA RxRg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=h8XVbQKdXCWJQp+umGqqBJDYSqgM/CA/nG8vr+0C1eI=; b=udZ0/9aNWgYsTHDPM4dUVO5MsfOU5JpciVYpY6w7gzf7GSGK2HSrmKdTeB2+kAinNA G/uuoO/oHnn+OSYIWdDtNcKduk4WAcnSWWVQvIXa7Ti7g6OVqm+VHXDC33k5m56tUh2W 3FZhneY0PSPi7+On07dkFz5r21uG9JN647YIBdvdsAXi+mmoAkYlnSwVX2obH0pW/o13 oJHr0/lIq10ME7qiAoILJmdBa1kxlPzRO+ZpHxYdbF0B2bxGBys4oqGCNIC8t8bQL+SM nL54Oo6a1d9cSfyVfRkKq6m/yMBZ8LbM9c7l0KxQmeCn/5Fp+v8lxaVYgOSTdd5KXHlq M7jg== X-Gm-Message-State: AOAM532zXKAWxYm1drslk26zHbrYEds/5tVJ9+87/vg5ipWJIQfj9IDV XgtZb4FVQy9DDc25wehemJY= X-Google-Smtp-Source: ABdhPJx0oSWkTIcVePmOGr3MP7l1aUvnjfFLGi3jRFhoD18Xd/+7p+YI0ELxSFW+uCwIujpdMG4UYQ== X-Received: by 2002:a17:902:d64d:b029:de:8aaa:d6ba with SMTP id y13-20020a170902d64db02900de8aaad6bamr9858688plh.0.1615494955254; Thu, 11 Mar 2021 12:35:55 -0800 (PST) Received: from edumazet1.svl.corp.google.com ([2620:15c:2c4:201:5186:d796:2218:6442]) by smtp.gmail.com with ESMTPSA id 25sm3232745pfh.199.2021.03.11.12.35.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Mar 2021 12:35:54 -0800 (PST) From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski Cc: netdev , Eric Dumazet , Eric Dumazet , Neal Cardwell , Yuchung Cheng , Neil Spring Subject: [PATCH net-next 3/3] tcp: remove obsolete check in __tcp_retransmit_skb() Date: Thu, 11 Mar 2021 12:35:06 -0800 Message-Id: <20210311203506.3450792-4-eric.dumazet@gmail.com> X-Mailer: git-send-email 2.31.0.rc2.261.g7f71774620-goog In-Reply-To: <20210311203506.3450792-1-eric.dumazet@gmail.com> References: <20210311203506.3450792-1-eric.dumazet@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Eric Dumazet TSQ provides a nice way to avoid bufferbloat on individual socket, including retransmit packets. We can get rid of the old heuristic: /* Do not sent more than we queued. 1/4 is reserved for possible * copying overhead: fragmentation, tunneling, mangling etc. */ if (refcount_read(&sk->sk_wmem_alloc) > min_t(u32, sk->sk_wmem_queued + (sk->sk_wmem_queued >> 2), sk->sk_sndbuf)) return -EAGAIN; This heuristic was giving false positives according to Jakub, whenever TX completions are delayed above RTT. (Ack packets are processed by TCP stack before clones are orphaned/freed) Signed-off-by: Eric Dumazet Reported-by: Jakub Kicinski Cc: Neal Cardwell Cc: Yuchung Cheng --- net/ipv4/tcp_output.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 0dbf208a4f2f17c630084e87f4a9a2ad0dc24168..bde781f46b41a5dd9eb8db3fb65b45d73e592b4b 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3151,14 +3151,6 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs) if (icsk->icsk_mtup.probe_size) icsk->icsk_mtup.probe_size = 0; - /* Do not sent more than we queued. 1/4 is reserved for possible - * copying overhead: fragmentation, tunneling, mangling etc. - */ - if (refcount_read(&sk->sk_wmem_alloc) > - min_t(u32, sk->sk_wmem_queued + (sk->sk_wmem_queued >> 2), - sk->sk_sndbuf)) - return -EAGAIN; - if (skb_still_in_host_queue(sk, skb)) return -EBUSY;