Messages in this thread |  | | From | Rusty Russell <> | Subject | Re: [PATCH V3 1/2] virtio-net: fix the set affinity bug when CPU IDs are not consecutive | Date | Wed, 09 Jan 2013 10:01:32 +1030 |
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Wanlong Gao <gaowanlong@cn.fujitsu.com> writes: > */ > static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb) > { > - int txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : > - smp_processor_id(); > + int txq = 0; > + > + if (skb_rx_queue_recorded(skb)) > + txq = skb_get_rx_queue(skb); > + else if ((txq = per_cpu(vq_index, smp_processor_id())) == -1) > + txq = 0;
You should use __get_cpu_var() instead of smp_processor_id() here, ie:
else if ((txq = __get_cpu_var(vq_index)) == -1)
And AFAICT, no reason to initialize txq to 0 to start with.
So:
int txq;
if (skb_rx_queue_recorded(skb)) txq = skb_get_rx_queue(skb); else { txq = __get_cpu_var(vq_index); if (txq == -1) txq = 0; }
Now, just to confirm, I assume this can happen even if we use vq_index, right, because of races with virtnet_set_channels?
while (unlikely(txq >= dev->real_num_tx_queues)) txq -= dev->real_num_tx_queues;
Thanks, Rusty.
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