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 <eduma...@google.com>
Cc: "Michael S. Tsirkin" <m...@redhat.com>
Cc: Jason Wang <jasow...@redhat.com>
---
drivers/net/virtio_net.c | 14 --------------
1 file changed, 14 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index
76592090522607a4bdf5422b1d49ec99c6fd68ac..dab504ec5e502be401cbfe9a8e3f0f572c0220ba
100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -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,
--
2.19.0.605.g01d371f741-goog
