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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: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jason Wang 2017-02-17 11:33:09 +08:00 committed by David S. Miller
parent f5a5772337
commit 61845d2072
1 changed files with 31 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

47
drivers/net/virtio_net.c
View File

@ -719,13 +719,13 @@ xdp_xmit:
return NULL;
}
static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
void *buf, unsigned int len)
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)