Merge branch 'tunnel_dst_caching'
Tom Herbert says:
====================
ipv4: Cache dst in tunnels
Version 3 of caching routes in tunnels.
Addressed some comments from Eric in this series.
There are two patches (variants) in the series:
1) One dst cached for each tunnel.
2) Percpu dst cache per tunnel to avoid false sharing
Testing with GRE tunnels on a 32 CPU host with bnx2x (RSS support
for GRE) shows a modest improvement in CPU utilization with these
patches running 200 TCP_RR netperf clients.
Without patches
71.22% CPU utilization
138/180/244 90/95/99% latencies
1.30465e+06 CPU/tps
18318 CPU/tps
With patches
69.84%
142/186/249 90/95/99% latencies
1.30827e+06
18732 CPU/tps
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 732f8c6..9e25b1b 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -38,6 +38,11 @@
struct rcu_head rcu_head;
};
+struct ip_tunnel_dst {
+ struct dst_entry __rcu *dst;
+ spinlock_t lock;
+};
+
struct ip_tunnel {
struct ip_tunnel __rcu *next;
struct hlist_node hash_node;
@@ -54,6 +59,8 @@
int hlen; /* Precalculated header length */
int mlink;
+ struct ip_tunnel_dst __percpu *dst_cache;
+
struct ip_tunnel_parm parms;
/* for SIT */
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 90ff957..e2c9cff 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -68,6 +68,63 @@
IP_TNL_HASH_BITS);
}
+static inline void __tunnel_dst_set(struct ip_tunnel_dst *idst,
+ struct dst_entry *dst)
+{
+ struct dst_entry *old_dst;
+
+ if (dst && (dst->flags & DST_NOCACHE))
+ dst = NULL;
+
+ spin_lock_bh(&idst->lock);
+ old_dst = rcu_dereference(idst->dst);
+ rcu_assign_pointer(idst->dst, dst);
+ dst_release(old_dst);
+ spin_unlock_bh(&idst->lock);
+}
+
+static inline void tunnel_dst_set(struct ip_tunnel *t, struct dst_entry *dst)
+{
+ __tunnel_dst_set(this_cpu_ptr(t->dst_cache), dst);
+}
+
+static inline void tunnel_dst_reset(struct ip_tunnel *t)
+{
+ tunnel_dst_set(t, NULL);
+}
+
+static void tunnel_dst_reset_all(struct ip_tunnel *t)
+{
+ int i;
+
+ for_each_possible_cpu(i)
+ __tunnel_dst_set(per_cpu_ptr(t->dst_cache, i), NULL);
+}
+
+static inline struct dst_entry *tunnel_dst_get(struct ip_tunnel *t)
+{
+ struct dst_entry *dst;
+
+ rcu_read_lock();
+ dst = rcu_dereference(this_cpu_ptr(t->dst_cache)->dst);
+ if (dst)
+ dst_hold(dst);
+ rcu_read_unlock();
+ return dst;
+}
+
+struct dst_entry *tunnel_dst_check(struct ip_tunnel *t, u32 cookie)
+{
+ struct dst_entry *dst = tunnel_dst_get(t);
+
+ if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
+ tunnel_dst_reset(t);
+ return NULL;
+ }
+
+ return dst;
+}
+
/* Often modified stats are per cpu, other are shared (netdev->stats) */
struct rtnl_link_stats64 *ip_tunnel_get_stats64(struct net_device *dev,
struct rtnl_link_stats64 *tot)
@@ -318,11 +375,10 @@
return ERR_PTR(err);
}
-static inline struct rtable *ip_route_output_tunnel(struct net *net,
- struct flowi4 *fl4,
- int proto,
- __be32 daddr, __be32 saddr,
- __be32 key, __u8 tos, int oif)
+static inline void init_tunnel_flow(struct flowi4 *fl4,
+ int proto,
+ __be32 daddr, __be32 saddr,
+ __be32 key, __u8 tos, int oif)
{
memset(fl4, 0, sizeof(*fl4));
fl4->flowi4_oif = oif;
@@ -331,7 +387,6 @@
fl4->flowi4_tos = tos;
fl4->flowi4_proto = proto;
fl4->fl4_gre_key = key;
- return ip_route_output_key(net, fl4);
}
static int ip_tunnel_bind_dev(struct net_device *dev)
@@ -350,14 +405,14 @@
struct flowi4 fl4;
struct rtable *rt;
- rt = ip_route_output_tunnel(tunnel->net, &fl4,
- tunnel->parms.iph.protocol,
- iph->daddr, iph->saddr,
- tunnel->parms.o_key,
- RT_TOS(iph->tos),
- tunnel->parms.link);
+ init_tunnel_flow(&fl4, iph->protocol, iph->daddr,
+ iph->saddr, tunnel->parms.o_key,
+ RT_TOS(iph->tos), tunnel->parms.link);
+ rt = ip_route_output_key(tunnel->net, &fl4);
+
if (!IS_ERR(rt)) {
tdev = rt->dst.dev;
+ tunnel_dst_set(tunnel, dst_clone(&rt->dst));
ip_rt_put(rt);
}
if (dev->type != ARPHRD_ETHER)
@@ -528,10 +583,11 @@
struct flowi4 fl4;
u8 tos, ttl;
__be16 df;
- struct rtable *rt; /* Route to the other host */
+ struct rtable *rt = NULL; /* Route to the other host */
unsigned int max_headroom; /* The extra header space needed */
__be32 dst;
int err;
+ bool connected = true;
inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
@@ -581,27 +637,39 @@
#endif
else
goto tx_error;
+
+ connected = false;
}
tos = tnl_params->tos;
if (tos & 0x1) {
tos &= ~0x1;
- if (skb->protocol == htons(ETH_P_IP))
+ if (skb->protocol == htons(ETH_P_IP)) {
tos = inner_iph->tos;
- else if (skb->protocol == htons(ETH_P_IPV6))
+ connected = false;
+ } else if (skb->protocol == htons(ETH_P_IPV6)) {
tos = ipv6_get_dsfield((const struct ipv6hdr *)inner_iph);
+ connected = false;
+ }
}
- rt = ip_route_output_tunnel(tunnel->net, &fl4,
- protocol,
- dst, tnl_params->saddr,
- tunnel->parms.o_key,
- RT_TOS(tos),
- tunnel->parms.link);
- if (IS_ERR(rt)) {
- dev->stats.tx_carrier_errors++;
- goto tx_error;
+ init_tunnel_flow(&fl4, protocol, dst, tnl_params->saddr,
+ tunnel->parms.o_key, RT_TOS(tos), tunnel->parms.link);
+
+ if (connected)
+ rt = (struct rtable *)tunnel_dst_check(tunnel, 0);
+
+ if (!rt) {
+ rt = ip_route_output_key(tunnel->net, &fl4);
+
+ if (IS_ERR(rt)) {
+ dev->stats.tx_carrier_errors++;
+ goto tx_error;
+ }
+ if (connected)
+ tunnel_dst_set(tunnel, dst_clone(&rt->dst));
}
+
if (rt->dst.dev == dev) {
ip_rt_put(rt);
dev->stats.collisions++;
@@ -696,6 +764,7 @@
if (set_mtu)
dev->mtu = mtu;
}
+ tunnel_dst_reset_all(t);
netdev_state_change(dev);
}
@@ -811,6 +880,7 @@
struct ip_tunnel *tunnel = netdev_priv(dev);
gro_cells_destroy(&tunnel->gro_cells);
+ free_percpu(tunnel->dst_cache);
free_percpu(dev->tstats);
free_netdev(dev);
}
@@ -989,8 +1059,21 @@
u64_stats_init(&ipt_stats->syncp);
}
+ tunnel->dst_cache = alloc_percpu(struct ip_tunnel_dst);
+ if (!tunnel->dst_cache) {
+ free_percpu(dev->tstats);
+ return -ENOMEM;
+ }
+
+ for_each_possible_cpu(i) {
+ struct ip_tunnel_dst *idst = per_cpu_ptr(tunnel->dst_cache, i);
+ idst-> dst = NULL;
+ spin_lock_init(&idst->lock);
+ }
+
err = gro_cells_init(&tunnel->gro_cells, dev);
if (err) {
+ free_percpu(tunnel->dst_cache);
free_percpu(dev->tstats);
return err;
}
@@ -1015,6 +1098,8 @@
/* fb_tunnel_dev will be unregisted in net-exit call. */
if (itn->fb_tunnel_dev != dev)
ip_tunnel_del(netdev_priv(dev));
+
+ tunnel_dst_reset_all(tunnel);
}
EXPORT_SYMBOL_GPL(ip_tunnel_uninit);