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Commit 61845d20 authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

virtio-net: batch stats updating 



We already have counters for sent/recv packets and sent/recv bytes.
Doing a batched update to reduce the number of
u64_stats_update_begin/end().

Take care not to bother with stats update when called
speculatively.

Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f5a57723

drivers/net/virtio_net.c

+31 −16
Original line number Diff line number Diff line
@@ -719,13 +719,13 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, 
	return NULL;

}



static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,

static int receive_buf(struct virtnet_info *vi, struct receive_queue *rq,

		       void *buf, unsigned int len)

{

	struct net_device *dev = vi->dev;

	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);

	struct sk_buff *skb;

	struct virtio_net_hdr_mrg_rxbuf *hdr;

	int ret;



	if (unlikely(len < vi->hdr_len + ETH_HLEN)) {

		pr_debug("%s: short packet %i\n", dev->name, len);
@@ -739,7 +739,7 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq, 
		} else {

			dev_kfree_skb(buf);

		}

		return;

		return 0;

	}



	if (vi->mergeable_rx_bufs)
@@ -750,14 +750,11 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq, 
		skb = receive_small(dev, vi, rq, buf, len);



	if (unlikely(!skb))

		return;

		return 0;



	hdr = skb_vnet_hdr(skb);



	u64_stats_update_begin(&stats->rx_syncp);

	stats->rx_bytes += skb->len;

	stats->rx_packets++;

	u64_stats_update_end(&stats->rx_syncp);

	ret = skb->len;



	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID)

		skb->ip_summed = CHECKSUM_UNNECESSARY;
@@ -775,11 +772,12 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq, 
		 ntohs(skb->protocol), skb->len, skb->pkt_type);



	napi_gro_receive(&rq->napi, skb);

	return;

	return ret;



frame_err:

	dev->stats.rx_frame_errors++;

	dev_kfree_skb(skb);

	return 0;

}



static unsigned int virtnet_get_headroom(struct virtnet_info *vi)
@@ -994,12 +992,13 @@ static void refill_work(struct work_struct *work) 
static int virtnet_receive(struct receive_queue *rq, int budget)

{

	struct virtnet_info *vi = rq->vq->vdev->priv;

	unsigned int len, received = 0;

	unsigned int len, received = 0, bytes = 0;

	void *buf;

	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);



	while (received < budget &&

	       (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {

		receive_buf(vi, rq, buf, len);

		bytes += receive_buf(vi, rq, buf, len);

		received++;

	}
@@ -1008,6 +1007,11 @@ static int virtnet_receive(struct receive_queue *rq, int budget) 
			schedule_delayed_work(&vi->refill, 0);

	}



	u64_stats_update_begin(&stats->rx_syncp);

	stats->rx_bytes += bytes;

	stats->rx_packets += received;

	u64_stats_update_end(&stats->rx_syncp);



	return received;

}
@@ -1056,17 +1060,28 @@ static void free_old_xmit_skbs(struct send_queue *sq) 
	unsigned int len;

	struct virtnet_info *vi = sq->vq->vdev->priv;

	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);

	unsigned int packets = 0;

	unsigned int bytes = 0;



	while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {

		pr_debug("Sent skb %p\n", skb);



		u64_stats_update_begin(&stats->tx_syncp);

		stats->tx_bytes += skb->len;

		stats->tx_packets++;

		u64_stats_update_end(&stats->tx_syncp);

		bytes += skb->len;

		packets++;



		dev_kfree_skb_any(skb);

	}



	/* Avoid overhead when no packets have been processed

	 * happens when called speculatively from start_xmit.

	 */

	if (!packets)

		return;



	u64_stats_update_begin(&stats->tx_syncp);

	stats->tx_bytes += bytes;

	stats->tx_packets += packets;

	u64_stats_update_end(&stats->tx_syncp);

}



static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)