From: Eric Dumazet Date: Sat, 29 Dec 2012 16:02:43 +0000 (+0000) Subject: veth: reduce stat overhead X-Git-Tag: v3.9-rc1~139^2~511 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2681128f0ced8aa4e66f221197e183cc16d244fe;p=platform%2Fkernel%2Flinux-3.10.git veth: reduce stat overhead veth stats are a bit bloated. There is no need to account transmit and receive stats, since they are absolutely symmetric. Also use a per device atomic64_t for the dropped counter, as it should never be used in fast path. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- diff --git a/drivers/net/veth.c b/drivers/net/veth.c index 95814d9..c048f8d 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -25,18 +25,15 @@ #define MIN_MTU 68 /* Min L3 MTU */ #define MAX_MTU 65535 /* Max L3 MTU (arbitrary) */ -struct veth_net_stats { - u64 rx_packets; - u64 rx_bytes; - u64 tx_packets; - u64 tx_bytes; - u64 rx_dropped; +struct pcpu_vstats { + u64 packets; + u64 bytes; struct u64_stats_sync syncp; }; struct veth_priv { - struct net_device *peer; - struct veth_net_stats __percpu *stats; + struct net_device *peer; + atomic64_t dropped; }; /* @@ -107,50 +104,30 @@ static const struct ethtool_ops veth_ethtool_ops = { .get_ethtool_stats = veth_get_ethtool_stats, }; -/* - * xmit - */ - static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev) { - struct net_device *rcv = NULL; - struct veth_priv *priv, *rcv_priv; - struct veth_net_stats *stats, *rcv_stats; - int length; - - priv = netdev_priv(dev); - rcv = priv->peer; - rcv_priv = netdev_priv(rcv); - - stats = this_cpu_ptr(priv->stats); - rcv_stats = this_cpu_ptr(rcv_priv->stats); + struct veth_priv *priv = netdev_priv(dev); + struct net_device *rcv = priv->peer; + int length = skb->len; /* don't change ip_summed == CHECKSUM_PARTIAL, as that - will cause bad checksum on forwarded packets */ + * will cause bad checksum on forwarded packets + */ if (skb->ip_summed == CHECKSUM_NONE && rcv->features & NETIF_F_RXCSUM) skb->ip_summed = CHECKSUM_UNNECESSARY; - length = skb->len; - if (dev_forward_skb(rcv, skb) != NET_RX_SUCCESS) - goto rx_drop; - - u64_stats_update_begin(&stats->syncp); - stats->tx_bytes += length; - stats->tx_packets++; - u64_stats_update_end(&stats->syncp); + if (likely(dev_forward_skb(rcv, skb) == NET_RX_SUCCESS)) { + struct pcpu_vstats *stats = this_cpu_ptr(dev->vstats); - u64_stats_update_begin(&rcv_stats->syncp); - rcv_stats->rx_bytes += length; - rcv_stats->rx_packets++; - u64_stats_update_end(&rcv_stats->syncp); - - return NETDEV_TX_OK; + u64_stats_update_begin(&stats->syncp); + stats->bytes += length; + stats->packets++; + u64_stats_update_end(&stats->syncp); + } else { + atomic64_inc(&priv->dropped); + } -rx_drop: - u64_stats_update_begin(&rcv_stats->syncp); - rcv_stats->rx_dropped++; - u64_stats_update_end(&rcv_stats->syncp); return NETDEV_TX_OK; } @@ -158,32 +135,42 @@ rx_drop: * general routines */ -static struct rtnl_link_stats64 *veth_get_stats64(struct net_device *dev, - struct rtnl_link_stats64 *tot) +static u64 veth_stats_one(struct pcpu_vstats *result, struct net_device *dev) { struct veth_priv *priv = netdev_priv(dev); int cpu; + result->packets = 0; + result->bytes = 0; for_each_possible_cpu(cpu) { - struct veth_net_stats *stats = per_cpu_ptr(priv->stats, cpu); - u64 rx_packets, rx_bytes, rx_dropped; - u64 tx_packets, tx_bytes; + struct pcpu_vstats *stats = per_cpu_ptr(dev->vstats, cpu); + u64 packets, bytes; unsigned int start; do { start = u64_stats_fetch_begin_bh(&stats->syncp); - rx_packets = stats->rx_packets; - tx_packets = stats->tx_packets; - rx_bytes = stats->rx_bytes; - tx_bytes = stats->tx_bytes; - rx_dropped = stats->rx_dropped; + packets = stats->packets; + bytes = stats->bytes; } while (u64_stats_fetch_retry_bh(&stats->syncp, start)); - tot->rx_packets += rx_packets; - tot->tx_packets += tx_packets; - tot->rx_bytes += rx_bytes; - tot->tx_bytes += tx_bytes; - tot->rx_dropped += rx_dropped; + result->packets += packets; + result->bytes += bytes; } + return atomic64_read(&priv->dropped); +} + +static struct rtnl_link_stats64 *veth_get_stats64(struct net_device *dev, + struct rtnl_link_stats64 *tot) +{ + struct veth_priv *priv = netdev_priv(dev); + struct pcpu_vstats one; + + tot->tx_dropped = veth_stats_one(&one, dev); + tot->tx_bytes = one.bytes; + tot->tx_packets = one.packets; + + tot->rx_dropped = veth_stats_one(&one, priv->peer); + tot->rx_bytes = one.bytes; + tot->rx_packets = one.packets; return tot; } @@ -228,24 +215,16 @@ static int veth_change_mtu(struct net_device *dev, int new_mtu) static int veth_dev_init(struct net_device *dev) { - struct veth_net_stats __percpu *stats; - struct veth_priv *priv; - - stats = alloc_percpu(struct veth_net_stats); - if (stats == NULL) + dev->vstats = alloc_percpu(struct pcpu_vstats); + if (!dev->vstats) return -ENOMEM; - priv = netdev_priv(dev); - priv->stats = stats; return 0; } static void veth_dev_free(struct net_device *dev) { - struct veth_priv *priv; - - priv = netdev_priv(dev); - free_percpu(priv->stats); + free_percpu(dev->vstats); free_netdev(dev); } diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 0e1b92a..6835b58 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1284,6 +1284,7 @@ struct net_device { struct pcpu_lstats __percpu *lstats; /* loopback stats */ struct pcpu_tstats __percpu *tstats; /* tunnel stats */ struct pcpu_dstats __percpu *dstats; /* dummy stats */ + struct pcpu_vstats __percpu *vstats; /* veth stats */ }; /* GARP */ struct garp_port __rcu *garp_port;