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authorMichael S. Tsirkin <mst@redhat.com>2021-04-13 01:30:45 -0400
committerMichael S. Tsirkin <mst@redhat.com>2021-07-08 07:49:01 -0400
commita7766ef18b33674fa164e2e2916cef16d4e17f43 (patch)
treebaa7ea0cb6c7e6e6439fb32ef7f52efb473c387f /drivers/net
parent8d622d21d24803408b256d96463eac4574dcf067 (diff)
virtio_net: disable cb aggressively
There are currently two cases where we poll TX vq not in response to a callback: start xmit and rx napi. We currently do this with callbacks enabled which can cause extra interrupts from the card. Used not to be a big issue as we run with interrupts disabled but that is no longer the case, and in some cases the rate of spurious interrupts is so high linux detects this and actually kills the interrupt. Fix up by disabling the callbacks before polling the tx vq. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/virtio_net.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 613aef630cdd..8a58a2f013af 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1516,7 +1516,10 @@ static void virtnet_poll_cleantx(struct receive_queue *rq)
return;
if (__netif_tx_trylock(txq)) {
- free_old_xmit_skbs(sq, true);
+ do {
+ virtqueue_disable_cb(sq->vq);
+ free_old_xmit_skbs(sq, true);
+ } while (unlikely(!virtqueue_enable_cb_delayed(sq->vq)));
if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS)
netif_tx_wake_queue(txq);
@@ -1691,10 +1694,14 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
bool use_napi = sq->napi.weight;
/* Free up any pending old buffers before queueing new ones. */
- free_old_xmit_skbs(sq, false);
+ do {
+ if (use_napi)
+ virtqueue_disable_cb(sq->vq);
+
+ free_old_xmit_skbs(sq, false);
- if (use_napi && kick)
- virtqueue_enable_cb_delayed(sq->vq);
+ } while (use_napi && kick &&
+ unlikely(!virtqueue_enable_cb_delayed(sq->vq)));
/* timestamp packet in software */
skb_tx_timestamp(skb);