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=-2.3 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 C4DC9C3F2D7 for ; Tue, 3 Mar 2020 21:05:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9FDD820CC7 for ; Tue, 3 Mar 2020 21:05:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732266AbgCCVFI (ORCPT ); Tue, 3 Mar 2020 16:05:08 -0500 Received: from www62.your-server.de ([213.133.104.62]:39888 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729880AbgCCVFI (ORCPT ); Tue, 3 Mar 2020 16:05:08 -0500 Received: from sslproxy02.your-server.de ([78.47.166.47]) by www62.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89_1) (envelope-from ) id 1j9Eim-00068r-G7; Tue, 03 Mar 2020 22:04:56 +0100 Received: from [85.7.42.192] (helo=pc-9.home) by sslproxy02.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1j9Eim-000Iju-3A; Tue, 03 Mar 2020 22:04:56 +0100 Subject: Re: [PATCH v4] netdev attribute to control xdpgeneric skb linearization To: Jakub Kicinski Cc: Willem de Bruijn , Luigi Rizzo , Network Development , =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , David Miller , hawk@kernel.org, "Jubran, Samih" , linux-kernel , ast@kernel.org, bpf@vger.kernel.org References: <20200228105435.75298-1-lrizzo@google.com> <20200228110043.2771fddb@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <3c27d9c0-eb17-b20f-2d10-01f3bdf8c0d6@iogearbox.net> <20200303125020.2baef01b@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> From: Daniel Borkmann Message-ID: Date: Tue, 3 Mar 2020 22:04:55 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20200303125020.2baef01b@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.102.2/25740/Tue Mar 3 13:12:16 2020) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 3/3/20 9:50 PM, Jakub Kicinski wrote: > On Tue, 3 Mar 2020 20:46:55 +0100 Daniel Borkmann wrote: >> Thus, when the data/data_end test fails in generic XDP, the user can >> call e.g. bpf_xdp_pull_data(xdp, 64) to make sure we pull in as much as >> is needed w/o full linearization and once done the data/data_end can be >> repeated to proceed. Native XDP will leave xdp->rxq->skb as NULL, but >> later we could perhaps reuse the same bpf_xdp_pull_data() helper for >> native with skb-less backing. Thoughts? > > I'm curious why we consider a xdpgeneric-only addition. Is attaching > a cls_bpf program noticeably slower than xdpgeneric? Yeah, agree, I'm curious about that part as well. Thanks, Daniel