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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 39708C5ACD6 for ; Wed, 18 Mar 2020 12:50:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0E63E2076D for ; Wed, 18 Mar 2020 12:50:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linux-powerpc-org.20150623.gappssmtp.com header.i=@linux-powerpc-org.20150623.gappssmtp.com header.b="NA5BCCk6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726892AbgCRMuX (ORCPT ); Wed, 18 Mar 2020 08:50:23 -0400 Received: from mail-vs1-f66.google.com ([209.85.217.66]:37906 "EHLO mail-vs1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726546AbgCRMuW (ORCPT ); Wed, 18 Mar 2020 08:50:22 -0400 Received: by mail-vs1-f66.google.com with SMTP id x206so7605882vsx.5 for ; Wed, 18 Mar 2020 05:50:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-powerpc-org.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=tNH5oppoky0OHGa5tXYcwyV7SJRdKkQrTvDjbdQHru4=; b=NA5BCCk6cEdsdxdych4EBOfRTF2f+xIX55/kbCWgDSx44xCejlGrWQVPFvMYTLJ3/w UERaGmqLf3LWko+XvLsAsrEqYUq0ZFzWsI2bmSRE9/r5GePZtFv4z7ql4tdzH2e7orjK 39u8iqGXTLm2C/f+bF51L7D2GNwvVqkUQhMTVxiI04J+vug3vmax0NdgLdaZ8GQSYcwr 0ku9IG4Wq7BUHpioN9okIkF6uk7yUTZFB2SsvGvxE1nW1NwsAHkyEgaFl6NPTKUIhYW6 YBocu8VeNhu8yZ0n030mCJnOzc/0vb8wLCzZaNa9lULMMc3dezVYSoUdsN6mv5mTV1bp vw9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=tNH5oppoky0OHGa5tXYcwyV7SJRdKkQrTvDjbdQHru4=; b=Prv1oOAc6QBn/WMfoK5K786/JFMNjpn6fr5QfuNLdmvfTiz7Cffa/8SfSk/9P0l+oP CTBFEa5Hv46AcQGH/95X9MRUYRNTHj3lAO8FctlDvOa8xstWFQ4YWWeums4STItKZHuh U5/W+E5Qhv8p/JpCJB6YfRJTIDhmxlHXMXCme8NKDnz+K2AS4o1IKpJpqU7KfhCgys4m 6FG12VP1HAzGH2VEfZ+yE9AtUA1o6kJtDxZaSK+IACOJHLrIo9ujD/r2ZWZnnFZ9LnT/ cTotwNkfUo03SMy5wY46O0vbmLpHoEiwNlIdpNQl7B7qKsREqe9szxsbmGbSLDvqfoo1 RTTg== X-Gm-Message-State: ANhLgQ3lLf18grJrInJj15h8BDj6FgUOSSjd7pZOuvTJmEIZbZXjwBgS XSP3C0pZ6WDdO6RFfiM4Bp/oqVjD2O77QAaYfxFO2g== X-Google-Smtp-Source: ADFU+vuGTbacJJyl1R90h0Jboo62I4NU99xdEygLBx6b4WhzEwyH/jgtPtVjq2yCEIPJ3MRUxjSt1XO7sNNC/UvJxVc= X-Received: by 2002:a67:df97:: with SMTP id x23mr3051735vsk.160.1584535820076; Wed, 18 Mar 2020 05:50:20 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a9f:3b21:0:0:0:0:0 with HTTP; Wed, 18 Mar 2020 05:50:19 -0700 (PDT) X-Originating-IP: [5.35.35.59] In-Reply-To: References: <1584364176-23346-1-git-send-email-kda@linux-powerpc.org> From: Denis Kirjanov Date: Wed, 18 Mar 2020 15:50:19 +0300 Message-ID: Subject: Re: [PATCH net-next v4] xen networking: add basic XDP support for xen-netfront To: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Cc: netdev@vger.kernel.org, ilias.apalodimas@linaro.org, wei.liu@kernel.org, paul@xen.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 3/18/20, J=C3=BCrgen Gro=C3=9F wrote: > 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. Ok, I'll try to measure some numbers. > > - 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). You can search for the "A practical introduction to XDP" tutorial. Actually there is a lot of information available regarding XDP, you can easily find it. > > - 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, ...). Currently we need only a header offset from netback driver so that we can p= ut custom encapsulation header if required and that's done using xen bus state switching, so that: - netback tells that it can adjust the header offset - netfront part reads it > > - 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. I've put the code to talk_to_netback which is called "when first setting up, and when resuming" If you see a problem with that please share. > > Finally I'd like to ask you to split up the patch into a netfront and > a netback one. Ok, will do. Thanks! > > > Juergen >