Re: [PATCH 4/5] virtio_net: add dedicated XDP transmit queues
From: John Fastabend <john.fastabend@gmail.com>
Date: 2016-11-19 02:44:17
On 16-11-18 06:10 PM, Jakub Kicinski wrote:
On Fri, 18 Nov 2016 13:09:53 -0800, Jakub Kicinski wrote:quoted
Looks very cool! :) On Fri, 18 Nov 2016 11:00:41 -0800, John Fastabend wrote:quoted
@@ -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.
quoted hunk ↗ jump to hunk
@@ -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;