Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760687AbcLWTcB (ORCPT ); Fri, 23 Dec 2016 14:32:01 -0500 Received: from www62.your-server.de ([213.133.104.62]:44401 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753118AbcLWTb7 (ORCPT ); Fri, 23 Dec 2016 14:31:59 -0500 Message-ID: <585D7BA9.50509@iogearbox.net> Date: Fri, 23 Dec 2016 20:31:53 +0100 From: Daniel Borkmann User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Jason Wang , mst@redhat.com, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org CC: john.r.fastabend@intel.com Subject: Re: [PATCH net 1/9] virtio-net: remove the warning before XDP linearizing References: <1482503852-12438-1-git-send-email-jasowang@redhat.com> <1482503852-12438-2-git-send-email-jasowang@redhat.com> In-Reply-To: <1482503852-12438-2-git-send-email-jasowang@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1409 Lines: 40 Hi Jason, On 12/23/2016 03:37 PM, Jason Wang wrote: > Since we use EWMA to estimate the size of rx buffer. When rx buffer > size is underestimated, it's usual to have a packet with more than one > buffers. Consider this is not a bug, remove the warning and correct > the comment before XDP linearizing. > > Cc: John Fastabend > Signed-off-by: Jason Wang > --- > drivers/net/virtio_net.c | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 08327e0..1067253 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -552,14 +552,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > struct page *xdp_page; > u32 act; > > - /* No known backend devices should send packets with > - * more than a single buffer when XDP conditions are > - * met. However it is not strictly illegal so the case > - * is handled as an exception and a warning is thrown. > - */ > + /* This happens when rx buffer size is underestimated */ > if (unlikely(num_buf > 1)) { > - bpf_warn_invalid_xdp_buffer(); Could you also remove the bpf_warn_invalid_xdp_buffer(), which got added just for this? Thanks. > /* linearize data for XDP */ > xdp_page = xdp_linearize_page(rq, num_buf, > page, offset, &len); >