From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [net-next PATCH v3 2/3] e1000: add initial XDP support Date: Mon, 12 Sep 2016 16:46:08 -0700 Message-ID: <1473723968.18970.111.camel@edumazet-glaptop3.roam.corp.google.com> References: <20160912220312.5610.77528.stgit@john-Precision-Tower-5810> <20160912221351.5610.29043.stgit@john-Precision-Tower-5810> <1473720399.18970.91.camel@edumazet-glaptop3.roam.corp.google.com> <20160912230745.GA24171@ast-mbp.thefacebook.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: John Fastabend , bblanco@plumgrid.com, jeffrey.t.kirsher@intel.com, brouer@redhat.com, davem@davemloft.net, xiyou.wangcong@gmail.com, intel-wired-lan@lists.osuosl.org, u9012063@gmail.com, netdev@vger.kernel.org To: Alexei Starovoitov Return-path: Received: from mail-pf0-f169.google.com ([209.85.192.169]:33405 "EHLO mail-pf0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751420AbcILXqK (ORCPT ); Mon, 12 Sep 2016 19:46:10 -0400 Received: by mail-pf0-f169.google.com with SMTP id g202so57268978pfb.0 for ; Mon, 12 Sep 2016 16:46:10 -0700 (PDT) In-Reply-To: <20160912230745.GA24171@ast-mbp.thefacebook.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2016-09-12 at 16:07 -0700, Alexei Starovoitov wrote: > yep. there are various ways to shoot yourself in the foot with xdp. > The simplest program that drops all the packets will make the box unpingable. Well, my comment was about XDP_TX only, not about XDP_DROP or driving a scooter on 101 highway ;) This XDP_TX thing was one of the XDP marketing stuff, but there is absolutely no documentation on it, warning users about possible limitations/outcomes. BTW, I am not sure mlx4 implementation even works, vs BQL : mlx4_en_xmit_frame() does not call netdev_tx_sent_queue(), but tx completion will call netdev_tx_completed_queue() -> crash Do we have one test to validate that a XDP_TX implementation is actually correct ?