From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BEA3024166D; Tue, 6 May 2025 17:49:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746553789; cv=none; b=WeSBEYewae3GfFvIBLp06wJ3NEK2xs/ui3a+hqBgtZ65Hzxbmm8CEupfgoPiUA59IPmHVjS6fsl6Ikmif5+xMA2MG4eUbLGbv58NGg59MDI3sGiIxhlqyL8Qbdc5pOdR6J1cdov7joNRQTT5KR23HWk/cBSeLlYDvdEbNZ2G6oc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746553789; c=relaxed/simple; bh=HxQaz8h7QlrV6FrmS0RXQ2Cl1/gSYYAu81d0EvJmUQk=; h=From:Date:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=jDYY3TD1JcnW9Yof4dwZBLUg+arnYC9idQUi8CQrVUEceCke129WvMpiS25QaWaYzM76BaM3hyrlspP/fny9dYeIZVOXW0jPWeHphPAKnPLPuyw0dkbM8Yt/2qakXASh6ZTr69mIIaPVyjct+uNUUBP6IgcOfQZOg7TTJyKPbNc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=koXQwthn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="koXQwthn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9FAB4C4CEE4; Tue, 6 May 2025 17:49:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746553789; bh=HxQaz8h7QlrV6FrmS0RXQ2Cl1/gSYYAu81d0EvJmUQk=; h=From:Date:To:cc:Subject:In-Reply-To:References:From; b=koXQwthnQuhIC2BX+myHvapaUnphkNQA5YznqrUeSbRpbo66I4BkWZNY+4yVftzCr ntSVGM5j1pDWthOOf7dSsNVG3pTe1iQNq9SiLGB8AUgtqQeCzsNYSb0WZE1kyrpGfK /EdvrY7PkJ5xFM1dn4hD9q0sNqLD7lQskIr6OGr2XuJY3o2heV4FZw/65teCf9g90E 22eIW+EI4hbTSfIQpFmLsn6btdOQmJ0soQd8TK6atN/m8qZQBXzcsJV12FM7vuAvOH zqp6mHkG/KM8h6aKDjgfFRhOofmRVGoGc2uXaPY5FS7csL4aC/rQ+e8dK2yD0kJm4k eOuw/jGRtqlMg== From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Tue, 6 May 2025 20:49:41 +0300 (EEST) To: Paolo Abeni cc: chia-yu.chang@nokia-bell-labs.com, horms@kernel.org, dsahern@kernel.org, kuniyu@amazon.com, bpf@vger.kernel.org, netdev@vger.kernel.org, dave.taht@gmail.com, jhs@mojatatu.com, kuba@kernel.org, stephen@networkplumber.org, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, edumazet@google.com, andrew+netdev@lunn.ch, donald.hunter@gmail.com, ast@fiberby.net, liuhangbin@gmail.com, shuah@kernel.org, linux-kselftest@vger.kernel.org, ncardwell@google.com, koen.de_schepper@nokia-bell-labs.com, g.white@cablelabs.com, ingemar.s.johansson@ericsson.com, mirja.kuehlewind@ericsson.com, cheshire@apple.com, rs.ietf@gmx.at, Jason_Livingood@comcast.com, vidhi_goel@apple.com Subject: Re: [PATCH v5 net-next 09/15] tcp: accecn: AccECN option In-Reply-To: <412724ed-f5a0-9749-8c50-4dd76afd4140@kernel.org> Message-ID: References: <20250422153602.54787-1-chia-yu.chang@nokia-bell-labs.com> <20250422153602.54787-10-chia-yu.chang@nokia-bell-labs.com> <412724ed-f5a0-9749-8c50-4dd76afd4140@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="8323328-599366579-1746553781=:1002" This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323328-599366579-1746553781=:1002 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: QUOTED-PRINTABLE On Tue, 6 May 2025, Ilpo J=E4rvinen wrote: > On Tue, 29 Apr 2025, Paolo Abeni wrote: > > On 4/22/25 5:35 PM, chia-yu.chang@nokia-bell-labs.com wrote: > > > @@ -1117,6 +1235,17 @@ static unsigned int tcp_established_options(st= ruct sock *sk, struct sk_buff *skb > > > =09=09opts->num_sack_blocks =3D 0; > > > =09} > > > =20 > > > +=09if (tcp_ecn_mode_accecn(tp) && > > > +=09 sock_net(sk)->ipv4.sysctl_tcp_ecn_option) { > > > +=09=09int saving =3D opts->num_sack_blocks > 0 ? 2 : 0; > > > +=09=09int remaining =3D MAX_TCP_OPTION_SPACE - size; > >=20 > > AFACS the above means tcp_options_fit_accecn() must clear any already > > set options, but apparently it does not do so. Have you tested with > > something adding largish options like mptcp? >=20 > This "fitting" for AccEcn option is not to make room for the option but t= o=20 > check if AccECN option fits and in what length, and how it can take=20 > advantage of some nop bytes when available to save option space. A minor correction. SACK blocks will naturally fill the entire option=20 space if there are enough holes which would "starve" AccECN from using=20 option space during loss recovery. Thus, AccECN option is allowed allowed grab some of that space from SACK. There's redundancy in SACK blocks=20 anyway so it shouldn't usually impact SACK signal much. --=20 i. --8323328-599366579-1746553781=:1002--