dummy: percpu stats and lockless xmit
Converts dummy network device driver to :
- percpu stats
- 64bit stats
- lockless xmit (NETIF_F_LLTX)
- performance features added (NETIF_F_SG | NETIF_F_FRAGLIST |
NETIF_F_TSO | NETIF_F_NO_CSUM | NETIF_F_HIGHDMA)
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c
index 37dcfdc..ff2d29b 100644
--- a/drivers/net/dummy.c
+++ b/drivers/net/dummy.c
@@ -36,6 +36,7 @@
#include <linux/moduleparam.h>
#include <linux/rtnetlink.h>
#include <net/rtnetlink.h>
+#include <linux/u64_stats_sync.h>
static int numdummies = 1;
@@ -55,21 +56,69 @@
{
}
+struct pcpu_dstats {
+ u64 tx_packets;
+ u64 tx_bytes;
+ struct u64_stats_sync syncp;
+};
+
+static struct rtnl_link_stats64 *dummy_get_stats64(struct net_device *dev,
+ struct rtnl_link_stats64 *stats)
+{
+ int i;
+
+ for_each_possible_cpu(i) {
+ const struct pcpu_dstats *dstats;
+ u64 tbytes, tpackets;
+ unsigned int start;
+
+ dstats = per_cpu_ptr(dev->dstats, i);
+ do {
+ start = u64_stats_fetch_begin(&dstats->syncp);
+ tbytes = dstats->tx_bytes;
+ tpackets = dstats->tx_packets;
+ } while (u64_stats_fetch_retry(&dstats->syncp, start));
+ stats->tx_bytes += tbytes;
+ stats->tx_packets += tpackets;
+ }
+ return stats;
+}
static netdev_tx_t dummy_xmit(struct sk_buff *skb, struct net_device *dev)
{
- dev->stats.tx_packets++;
- dev->stats.tx_bytes += skb->len;
+ struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
+
+ u64_stats_update_begin(&dstats->syncp);
+ dstats->tx_packets++;
+ dstats->tx_bytes += skb->len;
+ u64_stats_update_end(&dstats->syncp);
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}
+static int dummy_dev_init(struct net_device *dev)
+{
+ dev->dstats = alloc_percpu(struct pcpu_dstats);
+ if (!dev->dstats)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void dummy_dev_free(struct net_device *dev)
+{
+ free_percpu(dev->dstats);
+ free_netdev(dev);
+}
+
static const struct net_device_ops dummy_netdev_ops = {
+ .ndo_init = dummy_dev_init,
.ndo_start_xmit = dummy_xmit,
.ndo_validate_addr = eth_validate_addr,
.ndo_set_multicast_list = set_multicast_list,
.ndo_set_mac_address = dummy_set_address,
+ .ndo_get_stats64 = dummy_get_stats64,
};
static void dummy_setup(struct net_device *dev)
@@ -78,14 +127,17 @@
/* Initialize the device structure. */
dev->netdev_ops = &dummy_netdev_ops;
- dev->destructor = free_netdev;
+ dev->destructor = dummy_dev_free;
/* Fill in device structure with ethernet-generic values. */
dev->tx_queue_len = 0;
dev->flags |= IFF_NOARP;
dev->flags &= ~IFF_MULTICAST;
+ dev->features |= NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_TSO;
+ dev->features |= NETIF_F_NO_CSUM | NETIF_F_HIGHDMA | NETIF_F_LLTX;
random_ether_addr(dev->dev_addr);
}
+
static int dummy_validate(struct nlattr *tb[], struct nlattr *data[])
{
if (tb[IFLA_ADDRESS]) {