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sit: percpu stats accounting
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Maintain per_cpu tx_bytes, tx_packets, rx_bytes, rx_packets.

Other seldom used fields are kept in netdev->stats structure, possibly
unsafe.

This is a preliminary work to support lockless transmit path, and
correct RX stats, that are already unsafe.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Eric Dumazet authored and David S. Miller committed Sep 28, 2010
1 parent 3c97af9 commit 15fc1f7
Showing 1 changed file with 64 additions and 18 deletions.
82 changes: 64 additions & 18 deletions net/ipv6/sit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -63,8 +63,9 @@
#define HASH_SIZE 16
#define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)

static void ipip6_tunnel_init(struct net_device *dev);
static int ipip6_tunnel_init(struct net_device *dev);
static void ipip6_tunnel_setup(struct net_device *dev);
static void ipip6_dev_free(struct net_device *dev);

static int sit_net_id __read_mostly;
struct sit_net {
Expand All @@ -84,6 +85,33 @@ struct sit_net {
#define for_each_ip_tunnel_rcu(start) \
for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))

/* often modified stats are per cpu, other are shared (netdev->stats) */
struct pcpu_tstats {
unsigned long rx_packets;
unsigned long rx_bytes;
unsigned long tx_packets;
unsigned long tx_bytes;
};

static struct net_device_stats *ipip6_get_stats(struct net_device *dev)
{
struct pcpu_tstats sum = { 0 };
int i;

for_each_possible_cpu(i) {
const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);

sum.rx_packets += tstats->rx_packets;
sum.rx_bytes += tstats->rx_bytes;
sum.tx_packets += tstats->tx_packets;
sum.tx_bytes += tstats->tx_bytes;
}
dev->stats.rx_packets = sum.rx_packets;
dev->stats.rx_bytes = sum.rx_bytes;
dev->stats.tx_packets = sum.tx_packets;
dev->stats.tx_bytes = sum.tx_bytes;
return &dev->stats;
}
/*
* Must be invoked with rcu_read_lock
*/
Expand Down Expand Up @@ -214,7 +242,7 @@ static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
if (parms->name[0])
strlcpy(name, parms->name, IFNAMSIZ);
else
sprintf(name, "sit%%d");
strcpy(name, "sit%d");

dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
if (dev == NULL)
Expand All @@ -230,7 +258,8 @@ static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
nt = netdev_priv(dev);

nt->parms = *parms;
ipip6_tunnel_init(dev);
if (ipip6_tunnel_init(dev) < 0)
goto failed_free;
ipip6_tunnel_clone_6rd(dev, sitn);

if (parms->i_flags & SIT_ISATAP)
Expand All @@ -245,7 +274,7 @@ static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
return nt;

failed_free:
free_netdev(dev);
ipip6_dev_free(dev);
failed:
return NULL;
}
Expand Down Expand Up @@ -546,6 +575,8 @@ static int ipip6_rcv(struct sk_buff *skb)
tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
iph->saddr, iph->daddr);
if (tunnel != NULL) {
struct pcpu_tstats *tstats;

secpath_reset(skb);
skb->mac_header = skb->network_header;
skb_reset_network_header(skb);
Expand All @@ -561,7 +592,11 @@ static int ipip6_rcv(struct sk_buff *skb)
return 0;
}

skb_tunnel_rx(skb, tunnel->dev);
tstats = this_cpu_ptr(tunnel->dev->tstats);
tstats->rx_packets++;
tstats->rx_bytes += skb->len;

__skb_tunnel_rx(skb, tunnel->dev);

ipip6_ecn_decapsulate(iph, skb);

Expand Down Expand Up @@ -626,14 +661,13 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
struct pcpu_tstats *tstats;
struct iphdr *tiph = &tunnel->parms.iph;
struct ipv6hdr *iph6 = ipv6_hdr(skb);
u8 tos = tunnel->parms.iph.tos;
__be16 df = tiph->frag_off;
struct rtable *rt; /* Route to the other host */
struct net_device *tdev; /* Device to other host */
struct net_device *tdev; /* Device to other host */
struct iphdr *iph; /* Our new IP header */
unsigned int max_headroom; /* The extra header space needed */
__be32 dst = tiph->daddr;
Expand Down Expand Up @@ -704,28 +738,28 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
.oif = tunnel->parms.link,
.proto = IPPROTO_IPV6 };
if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
stats->tx_carrier_errors++;
dev->stats.tx_carrier_errors++;
goto tx_error_icmp;
}
}
if (rt->rt_type != RTN_UNICAST) {
ip_rt_put(rt);
stats->tx_carrier_errors++;
dev->stats.tx_carrier_errors++;
goto tx_error_icmp;
}
tdev = rt->dst.dev;

if (tdev == dev) {
ip_rt_put(rt);
stats->collisions++;
dev->stats.collisions++;
goto tx_error;
}

if (df) {
mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);

if (mtu < 68) {
stats->collisions++;
dev->stats.collisions++;
ip_rt_put(rt);
goto tx_error;
}
Expand Down Expand Up @@ -764,7 +798,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
if (!new_skb) {
ip_rt_put(rt);
txq->tx_dropped++;
dev->stats.tx_dropped++;
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}
Expand Down Expand Up @@ -800,14 +834,14 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
iph->ttl = iph6->hop_limit;

nf_reset(skb);

IPTUNNEL_XMIT();
tstats = this_cpu_ptr(dev->tstats);
__IPTUNNEL_XMIT(tstats, &dev->stats);
return NETDEV_TX_OK;

tx_error_icmp:
dst_link_failure(skb);
tx_error:
stats->tx_errors++;
dev->stats.tx_errors++;
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}
Expand Down Expand Up @@ -1084,12 +1118,19 @@ static const struct net_device_ops ipip6_netdev_ops = {
.ndo_start_xmit = ipip6_tunnel_xmit,
.ndo_do_ioctl = ipip6_tunnel_ioctl,
.ndo_change_mtu = ipip6_tunnel_change_mtu,
.ndo_get_stats = ipip6_get_stats,
};

static void ipip6_dev_free(struct net_device *dev)
{
free_percpu(dev->tstats);
free_netdev(dev);
}

static void ipip6_tunnel_setup(struct net_device *dev)
{
dev->netdev_ops = &ipip6_netdev_ops;
dev->destructor = free_netdev;
dev->destructor = ipip6_dev_free;

dev->type = ARPHRD_SIT;
dev->hard_header_len = LL_MAX_HEADER + sizeof(struct iphdr);
Expand All @@ -1101,7 +1142,7 @@ static void ipip6_tunnel_setup(struct net_device *dev)
dev->features |= NETIF_F_NETNS_LOCAL;
}

static void ipip6_tunnel_init(struct net_device *dev)
static int ipip6_tunnel_init(struct net_device *dev)
{
struct ip_tunnel *tunnel = netdev_priv(dev);

Expand All @@ -1112,6 +1153,11 @@ static void ipip6_tunnel_init(struct net_device *dev)
memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);

ipip6_tunnel_bind_dev(dev);
dev->tstats = alloc_percpu(struct pcpu_tstats);
if (!dev->tstats)
return -ENOMEM;

return 0;
}

static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
Expand Down

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