Re: [net-next rfc v7 1/3] virtio-net: separate fields of sending/receiving queue from virtnet_info

On Monday, December 03, 2012 12:25:42 PM Rusty Russell wrote:

Jason Wang [off-list ref] writes:

quoted

To support multiqueue transmitq/receiveq, the first step is to separate
queue related structure from virtnet_info. This patch introduce
send_queue and receive_queue structure and use the pointer to them as the
parameter in functions handling sending/receiving.

OK, seems like a straightforward xform: a few nit-picks:

quoted

+/* Internal representation of a receive virtqueue */
+struct receive_queue {
+	/* Virtqueue associated with this receive_queue */
+	struct virtqueue *vq;
+
+        struct napi_struct napi;
+
+        /* Number of input buffers, and max we've ever had. */
+        unsigned int num, max;

Weird whitespace here.

Oh, yes, will fix it.

quoted

+
+	/* Work struct for refilling if we run low on memory. */
+	struct delayed_work refill;

I can't really see the justificaiton for a refill per queue.  Just have
one work iterate all the queues if it happens, unless it happens often
(in which case, we need to look harder at this anyway).

But during this kind of iteration, we may need enable/disable the napi 
regardless of whether the receive queue has lots to be refilled. This may add 
extra latency. 

quoted

 struct virtnet_info {
 
 	struct virtio_device *vdev;

-	struct virtqueue *rvq, *svq, *cvq;
+	struct virtqueue *cvq;

 	struct net_device *dev;
 	struct napi_struct napi;

You leave napi here, and take it away in the next patch.  I think it's
supposed to go away now.

Yes, will remove it.

Thanks

Cheers,
Rusty.
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