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 AF93C433D9 for ; Wed, 16 Oct 2024 01:31:31 +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=1729042291; cv=none; b=Kgai7ZtPvj4t7rke30v6E9RPcT0BFWsP2HzhSyWBSH7fmWDPl3aPwJDhO6xEuWQ5n/97/JowvoPhSV3xW0fMlQZwc/czzGYwElvKUj82Wkf7jTe1HONER0175eQnr/X1FlXSmYq00kpwnhN14GGEyiw13qMw8k81CKjxGVLHUL8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729042291; c=relaxed/simple; bh=hhIZNNhbRehK/fRlkWPT21p4C5bvD8ibmSfksXpEVZI=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=q4+QPGZmD3mJ+Y9xFU4beOOZYUh/gQH4g7OApH7SuyQNFUGypgdFxc90me+T1GD4RZhI6EO0tyE1XKP21CKHhBkTw1aCWc23OO6riZ53c3f4GozqdpKvYPDwVlKdBiFOinjPlqkA61v3j2qghJZwSuGoQ1sLMaFhn0ud/6qbVjE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=paas4bPP; 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="paas4bPP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D9BEC4CEC6; Wed, 16 Oct 2024 01:31:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729042291; bh=hhIZNNhbRehK/fRlkWPT21p4C5bvD8ibmSfksXpEVZI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=paas4bPPjm5aMP8ZzhN1Gw86PG/w/ymq5ja8k/LM524yNM/eTDi5rMGGtJ4ASK7u0 yIq6xt8n8yX/y6CV7vLeSbJii9XEac3CGqwcPq5UG25jG1+P4iR9l6RItUjAj+rV5u oYpqz9TSB1zvK82/RwFEWIBPGPJqlG5ZkfNypEdUTFQ8vhdUQDLCmEwoQnLmOIfHXD 5aiUmDvPUX+aQRCBqkwKPM9rTXhwB0hUmRiw7wdi43M7QTk1/TPYHsvEKRkGlJ6J2u pEtsjuK6h79hQv6TiRYthwQIZb+8EbalwVXhdaZwDLEebzunjVaPHOlH63BKv6C2R7 nHRkp5HYXUc7w== Date: Tue, 15 Oct 2024 18:31:29 -0700 From: Jakub Kicinski To: chia-yu.chang@nokia-bell-labs.com Cc: netdev@vger.kernel.org, ij@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 net-next 09/44] gso: AccECN support Message-ID: <20241015183120.72eabc79@kicinski-fedora-PC1C0HJN> In-Reply-To: <20241015102940.26157-10-chia-yu.chang@nokia-bell-labs.com> References: <20241015102940.26157-1-chia-yu.chang@nokia-bell-labs.com> <20241015102940.26157-10-chia-yu.chang@nokia-bell-labs.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Tue, 15 Oct 2024 12:29:05 +0200 chia-yu.chang@nokia-bell-labs.com wrote: > From: Ilpo J=C3=A4rvinen >=20 > Handling the CWR flag differs between RFC 3168 ECN and AccECN. > With RFC 3168 ECN aware TSO (NETIF_F_TSO_ECN) CWR flag is cleared > starting from 2nd segment which is incompatible how AccECN handles > the CWR flag. Such super-segments are indicated by SKB_GSO_TCP_ECN. > With AccECN, CWR flag (or more accurately, the ACE field that also > includes ECE & AE flags) changes only when new packet(s) with CE > mark arrives so the flag should not be changed within a super-skb. > The new skb/feature flags are necessary to prevent such TSO engines > corrupting AccECN ACE counters by clearing the CWR flag (if the > CWR handling feature cannot be turned off). >=20 > If NIC is completely unaware of RFC3168 ECN (doesn't support > NETIF_F_TSO_ECN) or its TSO engine can be set to not touch CWR flag > despite supporting also NETIF_F_TSO_ECN, TSO could be safely used > with AccECN on such NIC. This should be evaluated per NIC basis > (not done in this patch series for any NICs). net/ethtool/common.c:52:35: warning: initializer overrides prior initializa= tion of this subobject [-Winitializer-overrides] 52 | [NETIF_F_FCOE_CRC_BIT] =3D "tx-checksum-fcoe-crc", | ^~~~~~~~~~~~~~~~~~~~~~ net/ethtool/common.c:35:30: note: previous initialization is here 35 | [NETIF_F_GSO_ACCECN_BIT] =3D "tx-tcp-accecn-segmentat= ion", | ^~~~~~~~~~~~~~~~~~~~~~~~~~= ~~