From 6d81f41c58c69ddde497e9e640ba5805aa26e78c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 27 Sep 2010 20:50:33 +0000 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- drivers/net/dummy.c | 58 +++++++++++++++++++++++++++++++++++++-- include/linux/netdevice.h | 1 + 2 files changed, 56 insertions(+), 3 deletions(-) diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c index 37dcfdc6345..ff2d29b1785 100644 --- a/drivers/net/dummy.c +++ b/drivers/net/dummy.c @@ -36,6 +36,7 @@ #include #include #include +#include static int numdummies = 1; @@ -55,21 +56,69 @@ static void set_multicast_list(struct net_device *dev) { } +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 @@ static void dummy_setup(struct net_device *dev) /* 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]) { diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index c2bec990bd1..6f0845e0b88 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1057,6 +1057,7 @@ struct net_device { void *ml_priv; struct pcpu_lstats __percpu *lstats; /* loopback stats */ struct pcpu_tstats __percpu *tstats; /* tunnel stats */ + struct pcpu_dstats __percpu *dstats; /* dummy stats */ }; /* GARP */ struct garp_port *garp_port; -- 2.20.1