Subject: Re: macvlan: optimizing the receive path?

From: Vlad Yasevich <[email-masked]>
Date: Mon, 06 Oct 2014 09:04:45 -0400

On 10/04/2014 08:42 PM, David Miller wrote:
> From: Jason Baron <[email-masked]>
> Date: Thu, 02 Oct 2014 16:28:13 -0400
> 
>> --- a/drivers/net/macvlan.c
>> +++ b/drivers/net/macvlan.c
>> @@ -321,8 +321,8 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
>>         skb->dev = dev;
>>         skb->pkt_type = PACKET_HOST;
>>  
>> -       ret = netif_rx(skb);
>> -
>> +      macvlan_count_rx(vlan, len, true, 0);
>> +      return RX_HANDLER_ANOTHER;
>>  out:
>>         macvlan_count_rx(vlan, len, ret == NET_RX_SUCCESS, 0);
>>         return RX_HANDLER_CONSUMED;
> 
> That last argument to macvlan_count_rx() is a bool and thus should be
> specified as "false".  Yes I know other areas of this file get it
> wrong too.
> 
> Also, what about GRO?  Won't we get GRO processing if we do this via
> netif_rx() but not via the RX_HANDLER_ANOTHER route?  Just curious...

Wouldn't GRO already happen at the lower level?  For macvlan-to-macvlan,
you'd typically have large packets so no need for GRO.

-vlad