Subject: Re: RFS seems to have incompatiblities with bridged vlans

From: Stephen Hemminger <[email-masked]>
Date: Mon, 7 Jun 2010 14:59:10 -0700

On Mon, 7 Jun 2010 22:36:11 +0200
Peter Lieven <[email-masked]> wrote:

> Hi,
> 
> i today tried out 2.6.32-rc2 and I see a lot of warning messages like this:
> 
> Jun  7 22:33:15 172.21.55.20 kernel: [ 3012.575884] br141 received packet on queue 4, but number of RX queues is 1
> 
> The host is a SMP system with 8 cores, so I think there is expected to be one rx queue per CPU, but it seems
> the bridge iface has only one.
> 

The bridge interface has no queues. It doesn't queue any packets. 
The test in receive packet path is not appropriate in this case.
Not sure what the right fix is. Pretending the bridge device has
multiple queues (num_queues == NUM_CPUS) is a possibility but
seems like overhead without real increase in parallelism.