virtio-net: clean tx descriptors from rx napi

Amortize the cost of virtual interrupts by doing both rx and tx work
on reception of a receive interrupt if tx napi is enabled. With
VIRTIO_F_EVENT_IDX, this suppresses most explicit tx completion
interrupts for bidirectional workloads.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Willem de Bruijn 2017-04-24 13:49:29 -04:00 committed by David S. Miller
parent ea7735d97b
commit 7b0411ef4a

View File

@ -1075,12 +1075,33 @@ static void free_old_xmit_skbs(struct send_queue *sq)
u64_stats_update_end(&stats->tx_syncp);
}
static void virtnet_poll_cleantx(struct receive_queue *rq)
{
struct virtnet_info *vi = rq->vq->vdev->priv;
unsigned int index = vq2rxq(rq->vq);
struct send_queue *sq = &vi->sq[index];
struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, index);
if (!sq->napi.weight)
return;
if (__netif_tx_trylock(txq)) {
free_old_xmit_skbs(sq);
__netif_tx_unlock(txq);
}
if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS)
netif_tx_wake_queue(txq);
}
static int virtnet_poll(struct napi_struct *napi, int budget)
{
struct receive_queue *rq =
container_of(napi, struct receive_queue, napi);
unsigned int received;
virtnet_poll_cleantx(rq);
received = virtnet_receive(rq, budget);
/* Out of packets? */