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=-5.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 76E61C18E5B for ; Mon, 16 Mar 2020 11:55:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 46B6A206E2 for ; Mon, 16 Mar 2020 11:55:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QBXRInlT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730938AbgCPLzV (ORCPT ); Mon, 16 Mar 2020 07:55:21 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:56367 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730895AbgCPLzV (ORCPT ); Mon, 16 Mar 2020 07:55:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584359719; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cBwRVHEr2REFxsn5N6zTYtaMJu4RfZd7/sp8yXrqHBU=; b=QBXRInlTer5MbO8Mq32pBlj8z+or2Ak65H8ojsYC1oXWPqekKV7bwZ+3H14FfN6PCW2fir yVfDniEX7AEKlHABipFsMQUUc98kJu8TSyxO45EOCQpgAYOp/9Jt4bgx6/3lKCPgNrgf59 chaWC+tS2ePX/EDfQ41qzk46jj+X1mw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-57-BJBSVhIWOreHmuvSOuWkWw-1; Mon, 16 Mar 2020 07:55:16 -0400 X-MC-Unique: BJBSVhIWOreHmuvSOuWkWw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CC6F1DB60; Mon, 16 Mar 2020 11:55:14 +0000 (UTC) Received: from carbon (ovpn-200-32.brq.redhat.com [10.40.200.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id B32B85C1B2; Mon, 16 Mar 2020 11:55:08 +0000 (UTC) Date: Mon, 16 Mar 2020 12:55:07 +0100 From: Jesper Dangaard Brouer To: Denis Kirjanov Cc: Edward Cree , David Miller , netdev@vger.kernel.org, linux-net-drivers@solarflare.com, mhabets@solarflare.com, cmclachlan@solarflare.com, ilias.apalodimas@linaro.org, lorenzo@kernel.org, "Jubran, Samih" , brouer@redhat.com, Willem de Bruijn Subject: Re: [PATCH net-next] sfc: fix XDP-redirect in this driver Message-ID: <20200316125507.1a8a92ba@carbon> In-Reply-To: References: <158410589474.499645.16292046086222118891.stgit@firesoul> <20200316.014927.1864775444299469362.davem@davemloft.net> <98fd3c0c-225b-d64c-a64f-ca497205d4ce@solarflare.com> <20200316113515.16f7e243@carbon> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, 16 Mar 2020 13:45:23 +0300 Denis Kirjanov wrote: > On 3/16/20, Jesper Dangaard Brouer wrote: > > On Mon, 16 Mar 2020 10:10:01 +0000 > > Edward Cree wrote: > > > >> On 16/03/2020 08:49, David Miller wrote: > >> > Solarflare folks, please review. > >> > >> This looks like a correct implementation of what it purports to do, so > >> Acked-by: Edward Cree > > > > Thanks for the review! > > > >> It did take me some digging to understand _why_ it was needed though; > >> Jesper, is there any documentation of the tailroom requirement? It > >> doesn't seem to be mentioned anywhere I could find. > > > > I admit that is is poorly documented. It is a requirement as both > > cpumap and veth have a dependency when they process the redirected > > packet. We/I also need to update the doc on one page per packet > > requirement, as it is (in-practice) no longer true. > > Hi Jesper, > > that means that's on-going work to add multi-buffer/page support to XDP, right? Yes, it seems that both Amazon and Google have a need for this. Do notice that there is a fair amount of work-ahead. I'm working on establishing a frame size/end, such that we can get reserved storage space for multi-buffer references/segments[3]. I know Samih from Amazon is working on the multi-buffer part of using this area. > > > > I'm noticing these bugs, because I'm working on a patchset that add > > tailroom extend, and also reserves this 'skb_shared_info' tailroom area. > > The real goal is to later add XDP multi-buffer support, using this > > 'skb_shared_info' tailroom area, as desc here[2] > > > > [2] > > https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org [3] https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org#storage-space-for-multi-buffer-referencessegments -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer