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;
>
