Subject: [PATCH net 9/9] hv_netvsc: defer queue selection to VF

From: Stephen Hemminger <[email-masked]>
Date: Thu, 1 Mar 2018 10:27:56 -0800

When VF is used for accelerated networking it will likely have
more queues (and different policy) than the synthetic NIC.
This patch defers the queue policy to the VF so that all the
queues can be used. This impacts workloads like local generate UDP.

Signed-off-by: Stephen Hemminger <[email-masked]>
---
 drivers/net/hyperv/netvsc_drv.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 1909c58e0a7e..e36f3ae6893b 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -322,8 +322,19 @@ static u16 netvsc_select_queue(struct net_device *ndev, struct sk_buff *skb,
 	rcu_read_lock();
 	vf_netdev = rcu_dereference(ndc->vf_netdev);
 	if (vf_netdev) {
-		txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : 0;
-		qdisc_skb_cb(skb)->slave_dev_queue_mapping = skb->queue_mapping;
+		const struct net_device_ops *vf_ops = vf_netdev->netdev_ops;
+
+		if (vf_ops->ndo_select_queue)
+			txq = vf_ops->ndo_select_queue(vf_netdev, skb,
+						       accel_priv, fallback);
+		else
+			txq = fallback(vf_netdev, skb);
+
+		/* Record the queue selected by VF so that it can be
+		 * used for common case where VF has more queues than
+		 * the synthetic device.
+		 */
+		qdisc_skb_cb(skb)->slave_dev_queue_mapping = txq;
 	} else {
 		txq = netvsc_pick_tx(ndev, skb);
 	}
-- 
2.16.1