Re: [rfc net-next v6 2/3] virtio_net: multiqueue support

[Ben Hutchings <bhutchings@solarflare.com>]

On Tue, 2012-11-13 at 08:40 +0200, Michael S. Tsirkin wrote:
> On Mon, Nov 05, 2012 at 11:38:39AM +1030, Rusty Russell wrote:
> > > @@ -924,11 +1032,10 @@ static void virtnet_get_ringparam(struct net_device *dev,
> > >  {
> > >  	struct virtnet_info *vi = netdev_priv(dev);
> > >  
> > > -	ring->rx_max_pending = virtqueue_get_vring_size(vi->rvq);
> > > -	ring->tx_max_pending = virtqueue_get_vring_size(vi->svq);
> > > +	ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
> > > +	ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
> > >  	ring->rx_pending = ring->rx_max_pending;
> > >  	ring->tx_pending = ring->tx_max_pending;
> > > -
> > >  }
> > 
> > This assumes all vqs are the same size.  I think this should probably
> > check: for mq mode, use the first vq, otherewise use the 0th.
> 
> For rx_pending/tx_pending I think what is required here is the
> actual number of outstanding buffers.
> Dave, Eric - right?
> 
> So this should be the total over all rings and to be useful,
> rx_max_pending/tx_max_pending should be the total too.

So far as I know, all current implementations use the number of
descriptors per ring here. virtio_net should be consistent with this.

Ben.

> > For bonus points, check this assertion at probe time.
> 
> Looks like we can easily support different queues too.
> 

-- 
Ben Hutchings, Staff Engineer, Solarflare
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