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net: dsa: User per-cpu 64-bit statistics

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During testing with a background iperf pushing 1Gbit/sec worth of
traffic and having both ifconfig and ethtool collect statistics, we
could see quite frequent deadlocks. Convert the often accessed DSA slave
network devices statistics to per-cpu 64-bit statistics to remove these
deadlocks and provide fast efficient statistics updates.

Fixes: f613ed665b ("net: dsa: Add support for 64-bit statistics")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Florian Fainelli 2017-08-03 21:33:27 -07:00 committed by David S. Miller
parent eaf6dc0338
commit 5f6b4e14ca
3 changed files with 58 additions and 24 deletions
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10
net/dsa/dsa.c
View File

@ -190,6 +190,7 @@ static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
{
struct dsa_switch_tree *dst = dev->dsa_ptr;
struct sk_buff *nskb = NULL;
struct pcpu_sw_netstats *s;
struct dsa_slave_priv *p;
if (unlikely(dst == NULL)) {
@ -213,10 +214,11 @@ static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
skb->pkt_type = PACKET_HOST;
skb->protocol = eth_type_trans(skb, skb->dev);
u64_stats_update_begin(&p->stats64.syncp);
p->stats64.rx_packets++;
p->stats64.rx_bytes += skb->len;
u64_stats_update_end(&p->stats64.syncp);
s = this_cpu_ptr(p->stats64);
u64_stats_update_begin(&s->syncp);
s->rx_packets++;
s->rx_bytes += skb->len;
u64_stats_update_end(&s->syncp);
netif_receive_skb(skb);

2
net/dsa/dsa_priv.h
View File

@ -77,7 +77,7 @@ struct dsa_slave_priv {
struct sk_buff * (*xmit)(struct sk_buff *skb,
struct net_device *dev);
struct pcpu_sw_netstats stats64;
struct pcpu_sw_netstats *stats64;
/* DSA port data, such as switch, port index, etc. */
struct dsa_port *dp;

70
net/dsa/slave.c
View File

@ -352,12 +352,14 @@ static inline netdev_tx_t dsa_netpoll_send_skb(struct dsa_slave_priv *p,
static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct dsa_slave_priv *p = netdev_priv(dev);
struct pcpu_sw_netstats *s;
struct sk_buff *nskb;
u64_stats_update_begin(&p->stats64.syncp);
p->stats64.tx_packets++;
p->stats64.tx_bytes += skb->len;
u64_stats_update_end(&p->stats64.syncp);
s = this_cpu_ptr(p->stats64);
u64_stats_update_begin(&s->syncp);
s->tx_packets++;
s->tx_bytes += skb->len;
u64_stats_update_end(&s->syncp);
/* Transmit function may have to reallocate the original SKB,
* in which case it must have freed it. Only free it here on error.
@ -596,15 +598,26 @@ static void dsa_slave_get_ethtool_stats(struct net_device *dev,
{
struct dsa_slave_priv *p = netdev_priv(dev);
struct dsa_switch *ds = p->dp->ds;
struct pcpu_sw_netstats *s;
unsigned int start;
int i;
do {
start = u64_stats_fetch_begin_irq(&p->stats64.syncp);
data[0] = p->stats64.tx_packets;
data[1] = p->stats64.tx_bytes;
data[2] = p->stats64.rx_packets;
data[3] = p->stats64.rx_bytes;
} while (u64_stats_fetch_retry_irq(&p->stats64.syncp, start));
for_each_possible_cpu(i) {
u64 tx_packets, tx_bytes, rx_packets, rx_bytes;
s = per_cpu_ptr(p->stats64, i);
do {
start = u64_stats_fetch_begin_irq(&s->syncp);
tx_packets = s->tx_packets;
tx_bytes = s->tx_bytes;
rx_packets = s->rx_packets;
rx_bytes = s->rx_bytes;
} while (u64_stats_fetch_retry_irq(&s->syncp, start));
data[0] += tx_packets;
data[1] += tx_bytes;
data[2] += rx_packets;
data[3] += rx_bytes;
}
if (ds->ops->get_ethtool_stats)
ds->ops->get_ethtool_stats(ds, p->dp->index, data + 4);
}
@ -879,16 +892,28 @@ static void dsa_slave_get_stats64(struct net_device *dev,
struct rtnl_link_stats64 *stats)
{
struct dsa_slave_priv *p = netdev_priv(dev);
struct pcpu_sw_netstats *s;
unsigned int start;
int i;
netdev_stats_to_stats64(stats, &dev->stats);
do {
start = u64_stats_fetch_begin_irq(&p->stats64.syncp);
stats->tx_packets = p->stats64.tx_packets;
stats->tx_bytes = p->stats64.tx_bytes;
stats->rx_packets = p->stats64.rx_packets;
stats->rx_bytes = p->stats64.rx_bytes;
} while (u64_stats_fetch_retry_irq(&p->stats64.syncp, start));
for_each_possible_cpu(i) {
u64 tx_packets, tx_bytes, rx_packets, rx_bytes;
s = per_cpu_ptr(p->stats64, i);
do {
start = u64_stats_fetch_begin_irq(&s->syncp);
tx_packets = s->tx_packets;
tx_bytes = s->tx_bytes;
rx_packets = s->rx_packets;
rx_bytes = s->rx_bytes;
} while (u64_stats_fetch_retry_irq(&s->syncp, start));
stats->tx_packets += tx_packets;
stats->tx_bytes += tx_bytes;
stats->rx_packets += rx_packets;
stats->rx_bytes += rx_bytes;
}
}
void dsa_cpu_port_ethtool_init(struct ethtool_ops *ops)
@ -1202,7 +1227,11 @@ int dsa_slave_create(struct dsa_switch *ds, struct device *parent,
slave_dev->vlan_features = master->vlan_features;
p = netdev_priv(slave_dev);
u64_stats_init(&p->stats64.syncp);
p->stats64 = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
if (!p->stats64) {
free_netdev(slave_dev);
return -ENOMEM;
}
p->dp = &ds->ports[port];
INIT_LIST_HEAD(&p->mall_tc_list);
p->xmit = dst->tag_ops->xmit;
@ -1217,6 +1246,7 @@ int dsa_slave_create(struct dsa_switch *ds, struct device *parent,
netdev_err(master, "error %d registering interface %s\n",
ret, slave_dev->name);
ds->ports[port].netdev = NULL;
free_percpu(p->stats64);
free_netdev(slave_dev);
return ret;
}
@ -1227,6 +1257,7 @@ int dsa_slave_create(struct dsa_switch *ds, struct device *parent,
if (ret) {
netdev_err(master, "error %d setting up slave phy\n", ret);
unregister_netdev(slave_dev);
free_percpu(p->stats64);
free_netdev(slave_dev);
return ret;
}
@ -1249,6 +1280,7 @@ void dsa_slave_destroy(struct net_device *slave_dev)
of_phy_deregister_fixed_link(port_dn);
}
unregister_netdev(slave_dev);
free_percpu(p->stats64);
free_netdev(slave_dev);
}