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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 7493FC10DCE for ; Wed, 18 Mar 2020 11:16:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4BE172076C for ; Wed, 18 Mar 2020 11:16:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727520AbgCRLQ1 (ORCPT ); Wed, 18 Mar 2020 07:16:27 -0400 Received: from mx2.suse.de ([195.135.220.15]:52250 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726550AbgCRLQ1 (ORCPT ); Wed, 18 Mar 2020 07:16:27 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id CE580B25F; Wed, 18 Mar 2020 11:16:25 +0000 (UTC) Subject: Re: [PATCH net-next v4] xen networking: add basic XDP support for xen-netfront To: Denis Kirjanov , netdev@vger.kernel.org Cc: ilias.apalodimas@linaro.org, wei.liu@kernel.org, paul@xen.org References: <1584364176-23346-1-git-send-email-kda@linux-powerpc.org> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: Date: Wed, 18 Mar 2020 12:16:25 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <1584364176-23346-1-git-send-email-kda@linux-powerpc.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 16.03.20 14:09, Denis Kirjanov wrote: > The patch adds a basic XDP processing to xen-netfront driver. > > We ran an XDP program for an RX response received from netback > driver. Also we request xen-netback to adjust data offset for > bpf_xdp_adjust_head() header space for custom headers. This is in no way a "verbose patch descriprion". I'm missing: - Why are you doing this. "Add XDP support" is not enough, for such a change I'd like to see some performance numbers to get an idea of the improvement to expect, or which additional functionality for the user is available. - A short description for me as a Xen maintainer with only basic networking know-how, what XDP programs are about (a link to some more detailed doc is enough, of course) and how the interface is working (especially for switching between XDP mode and normal SKB processing). - A proper description of the netfront/netback communication when enabling or disabling XDP mode (who is doing what, is silencing of the virtual adapter required, ...). - Reasoning why the suggested changes of frontend and backend state are no problem for special cases like hot-remove of an interface or live migration or suspend of the guest. Finally I'd like to ask you to split up the patch into a netfront and a netback one. Juergen