From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [PATCH RFC 1/3] xdp: Infrastructure to generalize XDP Date: Wed, 21 Sep 2016 21:56:58 +0200 Message-ID: <20160921215658.2c61ed5e@redhat.com> References: <1474408824-418864-1-git-send-email-tom@herbertland.com> <1474408824-418864-2-git-send-email-tom@herbertland.com> <20160920224416.GF3291@pox.localdomain> <20160920230927.GG3291@pox.localdomain> <20160920234347.GH3291@pox.localdomain> <20160921115545.GA12789@pox.localdomain> <20160921144800.GB13991@pox.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Thomas Graf , "David S. Miller" , Linux Kernel Network Developers , Kernel Team , Tariq Toukan , Brenden Blanco , Alexei Starovoitov , Eric Dumazet , brouer@redhat.com To: Tom Herbert Return-path: Received: from mx1.redhat.com ([209.132.183.28]:60312 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755582AbcIUT5F (ORCPT ); Wed, 21 Sep 2016 15:57:05 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 21 Sep 2016 08:08:34 -0700 Tom Herbert wrote: > On Wed, Sep 21, 2016 at 7:48 AM, Thomas Graf wrote: > > On 09/21/16 at 07:19am, Tom Herbert wrote: > >> certain design that because of constraints on one kernel interface. As > >> a kernel developer I want flexibility on how we design and implement > >> things! > > > > Perfectly valid argument. I reviewed your ILA changes and did not > > object to them. > > > > > >> I think there are two questions that this patch set poses for the > >> community wrt XDP: > >> > >> #1: Should we allow alternate code to run in XDP other than BPF? > >> #2: If #1 is true what is the best way to implement that? > >> > >> If the answer to #1 is "no" then the answer to #2 is irrelevant. So > >> with this RFC I'm hoping we can come the agreement on questions #1. I vote yes to #1. > > I'm not opposed to running non-BPF code at XDP. I'm against adding > > a linked list of hook consumers. I also worry about the performance impact of a linked list. We should simple benchmark it instead of discussing it! ;-) > > Would anyone require to run XDP-BPF in combination ILA? Or XDP-BPF > > in combination with a potential XDP-nftables? We don't know yet I > > guess. > > > Right. Admittedly, I feel like we owe a bit of reciprocity to > nftables. For ILA we are using the NF_INET_PRE_ROUTING hook with our > own code (looks like ipvlan set nfhooks as well). This works really > well and saves the value of early demux in ILA. Had we not had the > ability to use nfhooks in this fashion it's likely we would have had > to create another hook (we did try putting translation in nftables > rules but that was too inefficient for ILA). Thinking about it, I actually think Tom is proposing a very valid user of the XDP hook, which is the kernel itself. And Tom even have a real first user ILA. The way I read the ILA-RFC-draft[1], the XDP hook would benefit the NVE (Network Virtualization Edge) component, which can run separately or run on the Tenant System, where the latter case could use XDP_PASS. [1] https://www.ietf.org/archive/id/draft-herbert-nvo3-ila-02.txt -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer