6 Nov
2020
6 Nov
'20
9:27 a.m.
On 06.11.2020 08:48, Heiner Kallweit wrote:
On 06.11.2020 02:14, Jakub Kicinski wrote:
For rx_dropped and tx_dropped it's easy, however tun also has a per-cpu
counter for rx_frame_errors that is incremented if virtio_net_hdr_to_skb()
fails. Not sure how to deal best with this one.
On Wed, 4 Nov 2020 15:25:24 +0100 Heiner Kallweit
wrote:
Thanks, yes that should be possible. Here we speak about tx_dropped,
but AFAICS the same applies as for rx_dropped. Will change it accordingly
in a v3.
@@ -1066,7 +1054,7 @@ static netdev_tx_t
tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
return NETDEV_TX_OK;
drop:
- this_cpu_inc(tun->pcpu_stats->tx_dropped);
+ dev->stats.tx_dropped++;
skb_tx_error(skb);
kfree_skb(skb);
rcu_read_unlock();
This is no longer atomic. Multiple CPUs may try to update it at the
same time.
Do you know what the story on dev->rx_dropped is? The kdoc says drivers
are not supposed to use it but:
drivers/net/ipvlan/ipvlan_core.c:
atomic_long_inc(&skb->dev->rx_dropped);
drivers/net/macvlan.c: atomic_long_inc(&skb->dev->rx_dropped);
drivers/net/vxlan.c: atomic_long_inc(&vxlan->dev->rx_dropped);
Maybe tun can use it, too?