virtio_net: remove ndo_poll_controller (260dd2c3) · Commits · 戴 / test

As diagnosed by Song Liu, ndo_poll_controller() can be very dangerous on loaded hosts, since the cpu calling ndo_poll_controller() might steal all NAPI contexts (for all RX/TX queues of the NIC). This capture can last for unlimited amount of time, since one cpu is generally not able to drain all the queues under load. virto_net uses NAPI for TX completions, so we better let core networking stack call the napi->poll() to avoid the capture. Signed-off-by:

Eric Dumazet <edumazet@google.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/virtio_net.c

+0 −14

Original line number	Diff line number	Diff line
		@@ -1699,17 +1699,6 @@ static void virtnet_stats(struct net_device *dev,
		tot->rx_frame_errors = dev->stats.rx_frame_errors;
		}

		#ifdef CONFIG_NET_POLL_CONTROLLER
		static void virtnet_netpoll(struct net_device *dev)
		{
		struct virtnet_info *vi = netdev_priv(dev);
		int i;

		for (i = 0; i < vi->curr_queue_pairs; i++)
		napi_schedule(&vi->rq[i].napi);
		}
		#endif

		static void virtnet_ack_link_announce(struct virtnet_info *vi)
		{
		rtnl_lock();
		@@ -2447,9 +2436,6 @@ static const struct net_device_ops virtnet_netdev = {
		.ndo_get_stats64 = virtnet_stats,
		.ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
		.ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
		#ifdef CONFIG_NET_POLL_CONTROLLER
		.ndo_poll_controller = virtnet_netpoll,
		#endif
		.ndo_bpf = virtnet_xdp,
		.ndo_xdp_xmit = virtnet_xdp_xmit,
		.ndo_features_check = passthru_features_check,

Admin message