From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Fastabend Subject: Re: [PATCH 4/5] virtio_net: add dedicated XDP transmit queues Date: Fri, 18 Nov 2016 18:43:55 -0800 Message-ID: <582FBC6B.8000902@gmail.com> References: <20161118185517.16137.92123.stgit@john-Precision-Tower-5810> <20161118190041.16137.48399.stgit@john-Precision-Tower-5810> <20161118130953.7bf2d71d@laptop> <20161118181004.4c15a6a1@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: tgraf@suug.ch, shm@cumulusnetworks.com, alexei.starovoitov@gmail.com, daniel@iogearbox.net, davem@davemloft.net, john.r.fastabend@intel.com, netdev@vger.kernel.org, bblanco@plumgrid.com, brouer@redhat.com To: Jakub Kicinski Return-path: Received: from mail-pg0-f67.google.com ([74.125.83.67]:36299 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752183AbcKSCoR (ORCPT ); Fri, 18 Nov 2016 21:44:17 -0500 Received: by mail-pg0-f67.google.com with SMTP id x23so22198994pgx.3 for ; Fri, 18 Nov 2016 18:44:17 -0800 (PST) In-Reply-To: <20161118181004.4c15a6a1@laptop> Sender: netdev-owner@vger.kernel.org List-ID: On 16-11-18 06:10 PM, Jakub Kicinski wrote: > On Fri, 18 Nov 2016 13:09:53 -0800, Jakub Kicinski wrote: >> Looks very cool! :) >> >> On Fri, 18 Nov 2016 11:00:41 -0800, John Fastabend wrote: >>> @@ -1542,12 +1546,34 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog) >>> return -EINVAL; >>> } >>> >>> + curr_qp = vi->curr_queue_pairs - vi->xdp_queue_pairs; >>> + if (prog) >>> + xdp_qp = num_online_cpus(); >> >> Is num_online_cpus() correct here? > > Sorry, I don't know the virto_net code, so I'm probably wrong. I was > concerned whether the number of cpus can change but also that the cpu > mask may be sparse and therefore offsetting by smp_processor_id() > into the queue table below could bring trouble. > Seem like a valid concerns to me how about num_possible_cpus() instead. > @@ -353,9 +381,15 @@ static u32 do_xdp_prog(struct virtnet_info *vi, > switch (act) { > case XDP_PASS: > return XDP_PASS; > + case XDP_TX: > + qp = vi->curr_queue_pairs - > + vi->xdp_queue_pairs + > + smp_processor_id(); > + xdp.data = buf + (vi->mergeable_rx_bufs ? 0 : 4); > + virtnet_xdp_xmit(vi, qp, &xdp); > + return XDP_TX; > default: > bpf_warn_invalid_xdp_action(act); > - case XDP_TX: > case XDP_ABORTED: > case XDP_DROP: > return XDP_DROP; >