virtio-net: per cpu 64 bit stats (v2)

Use per-cpu variables to maintain 64 bit statistics.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@conan.davemloft.net>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index be3686a298dab7cc71d75d04b7c7346e84848356..fbea637eb742a53459e53878b4a8a0ed42b7813c 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -40,6 +40,15 @@ module_param(gso, bool, 0444);
 
 #define VIRTNET_SEND_COMMAND_SG_MAX    2
 
+struct virtnet_stats {
+       struct u64_stats_sync syncp;
+       u64 tx_bytes;
+       u64 tx_packets;
+
+       u64 rx_bytes;
+       u64 rx_packets;
+};
+
 struct virtnet_info {
        struct virtio_device *vdev;
        struct virtqueue *rvq, *svq, *cvq;
@@ -56,6 +65,9 @@ struct virtnet_info {
        /* Host will merge rx buffers for big packets (shake it! shake it!) */
        bool mergeable_rx_bufs;
 
+       /* Active statistics */
+       struct virtnet_stats __percpu *stats;
+
        /* Work struct for refilling if we run low on memory. */
        struct delayed_work refill;
 
@@ -209,7 +221,6 @@ static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
                        skb->dev->stats.rx_length_errors++;
                        return -EINVAL;
                }
-
                page = virtqueue_get_buf(vi->rvq, &len);
                if (!page) {
                        pr_debug("%s: rx error: %d buffers missing\n",
@@ -217,6 +228,7 @@ static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
                        skb->dev->stats.rx_length_errors++;
                        return -EINVAL;
                }
+
                if (len > PAGE_SIZE)
                        len = PAGE_SIZE;
 
@@ -230,6 +242,7 @@ static int receive_mergeable(struct virtnet_info *vi, struct sk_buff *skb)
 static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
 {
        struct virtnet_info *vi = netdev_priv(dev);
+       struct virtnet_stats __percpu *stats = this_cpu_ptr(vi->stats);
        struct sk_buff *skb;
        struct page *page;
        struct skb_vnet_hdr *hdr;
@@ -265,8 +278,11 @@ static void receive_buf(struct net_device *dev, void *buf, unsigned int len)
 
        hdr = skb_vnet_hdr(skb);
        skb->truesize += skb->data_len;
-       dev->stats.rx_bytes += skb->len;
-       dev->stats.rx_packets++;
+
+       u64_stats_update_begin(&stats->syncp);
+       stats->rx_bytes += skb->len;
+       stats->rx_packets++;
+       u64_stats_update_end(&stats->syncp);
 
        if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
                pr_debug("Needs csum!\n");
@@ -515,11 +531,16 @@ static unsigned int free_old_xmit_skbs(struct virtnet_info *vi)
 {
        struct sk_buff *skb;
        unsigned int len, tot_sgs = 0;
+       struct virtnet_stats __percpu *stats = this_cpu_ptr(vi->stats);
 
        while ((skb = virtqueue_get_buf(vi->svq, &len)) != NULL) {
                pr_debug("Sent skb %p\n", skb);
-               vi->dev->stats.tx_bytes += skb->len;
-               vi->dev->stats.tx_packets++;
+
+               u64_stats_update_begin(&stats->syncp);
+               stats->tx_bytes += skb->len;
+               stats->tx_packets++;
+               u64_stats_update_end(&stats->syncp);
+
                tot_sgs += skb_vnet_hdr(skb)->num_sg;
                dev_kfree_skb_any(skb);
        }
@@ -641,6 +662,40 @@ static int virtnet_set_mac_address(struct net_device *dev, void *p)
        return 0;
 }
 
+static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
+                                              struct rtnl_link_stats64 *tot)
+{
+       struct virtnet_info *vi = netdev_priv(dev);
+       int cpu;
+       unsigned int start;
+
+       for_each_possible_cpu(cpu) {
+               struct virtnet_stats __percpu *stats
+                       = per_cpu_ptr(vi->stats, cpu);
+               u64 tpackets, tbytes, rpackets, rbytes;
+
+               do {
+                       start = u64_stats_fetch_begin(&stats->syncp);
+                       tpackets = stats->tx_packets;
+                       tbytes   = stats->tx_bytes;
+                       rpackets = stats->rx_packets;
+                       rbytes   = stats->rx_bytes;
+               } while (u64_stats_fetch_retry(&stats->syncp, start));
+
+               tot->rx_packets += rpackets;
+               tot->tx_packets += tpackets;
+               tot->rx_bytes   += rbytes;
+               tot->tx_bytes   += tbytes;
+       }
+
+       tot->tx_dropped = dev->stats.tx_dropped;
+       tot->rx_dropped = dev->stats.rx_dropped;
+       tot->rx_length_errors = dev->stats.rx_length_errors;
+       tot->rx_frame_errors = dev->stats.rx_frame_errors;
+
+       return tot;
+}
+
 #ifdef CONFIG_NET_POLL_CONTROLLER
 static void virtnet_netpoll(struct net_device *dev)
 {
@@ -650,6 +705,14 @@ static void virtnet_netpoll(struct net_device *dev)
 }
 #endif
 
+static void virtnet_free(struct net_device *dev)
+{
+       struct virtnet_info *vi = netdev_priv(dev);
+
+       free_percpu(vi->stats);
+       free_netdev(dev);
+}
+
 static int virtnet_open(struct net_device *dev)
 {
        struct virtnet_info *vi = netdev_priv(dev);
@@ -835,6 +898,7 @@ static const struct net_device_ops virtnet_netdev = {
        .ndo_set_mac_address = virtnet_set_mac_address,
        .ndo_set_rx_mode     = virtnet_set_rx_mode,
        .ndo_change_mtu      = virtnet_change_mtu,
+       .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
@@ -895,6 +959,8 @@ static int virtnet_probe(struct virtio_device *vdev)
        /* Set up network device as normal. */
        dev->netdev_ops = &virtnet_netdev;
        dev->features = NETIF_F_HIGHDMA;
+       dev->destructor = virtnet_free;
+
        SET_ETHTOOL_OPS(dev, &virtnet_ethtool_ops);
        SET_NETDEV_DEV(dev, &vdev->dev);
 
@@ -939,6 +1005,11 @@ static int virtnet_probe(struct virtio_device *vdev)
        vi->vdev = vdev;
        vdev->priv = vi;
        vi->pages = NULL;
+       vi->stats = alloc_percpu(struct virtnet_stats);
+       err = -ENOMEM;
+       if (vi->stats == NULL)
+               goto free;
+
        INIT_DELAYED_WORK(&vi->refill, refill_work);
        sg_init_table(vi->rx_sg, ARRAY_SIZE(vi->rx_sg));
        sg_init_table(vi->tx_sg, ARRAY_SIZE(vi->tx_sg));
@@ -958,7 +1029,7 @@ static int virtnet_probe(struct virtio_device *vdev)
 
        err = vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names);
        if (err)
-               goto free;
+               goto free_stats;
 
        vi->rvq = vqs[0];
        vi->svq = vqs[1];
@@ -1003,6 +1074,8 @@ unregister:
        cancel_delayed_work_sync(&vi->refill);
 free_vqs:
        vdev->config->del_vqs(vdev);
+free_stats:
+       free_percpu(vi->stats);
 free:
        free_netdev(dev);
        return err;