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ipv4: Use percpu Cache route in IP tunnels 

percpu route cache eliminates share of dst refcnt between CPUs.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Herbert 2014-01-02 11:48:33 -08:00 committed by David S. Miller
parent 7d442fab0a
commit 9a4aa9af44
2 changed files with 38 additions and 14 deletions
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8
include/net/ip_tunnels.h
View File

@ -38,6 +38,11 @@ struct ip_tunnel_prl_entry {
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;
@ -54,8 +59,7 @@ struct ip_tunnel {
int hlen; /* Precalculated header length */
int mlink;
struct dst_entry __rcu *dst_cache;
spinlock_t dst_lock;
struct ip_tunnel_dst __percpu *dst_cache;
struct ip_tunnel_parm parms;

44
net/ipv4/ip_tunnel.c
View File

@ -68,23 +68,24 @@ static unsigned int ip_tunnel_hash(struct ip_tunnel_net *itn,
IP_TNL_HASH_BITS);
}
static inline void __tunnel_dst_set(struct ip_tunnel *t, struct dst_entry *dst)
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(&t->dst_lock);
old_dst = rcu_dereference_raw(t->dst_cache);
rcu_assign_pointer(t->dst_cache, dst);
spin_lock_bh(&idst->lock);
old_dst = rcu_dereference(idst->dst);
rcu_assign_pointer(idst->dst, dst);
dst_release(old_dst);
spin_unlock_bh(&t->dst_lock);
spin_unlock_bh(&idst->lock);
}
static inline void tunnel_dst_set(struct ip_tunnel *t, struct dst_entry *dst)
{
__tunnel_dst_set(t, dst);
__tunnel_dst_set(this_cpu_ptr(t->dst_cache), dst);
}
static inline void tunnel_dst_reset(struct ip_tunnel *t)
@ -92,12 +93,20 @@ 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(t->dst_cache);
dst = rcu_dereference(this_cpu_ptr(t->dst_cache)->dst);
if (dst)
dst_hold(dst);
rcu_read_unlock();
@ -755,7 +764,7 @@ static void ip_tunnel_update(struct ip_tunnel_net *itn,
if (set_mtu)
dev->mtu = mtu;
}
tunnel_dst_reset(t);
tunnel_dst_reset_all(t);
netdev_state_change(dev);
}
@ -871,6 +880,7 @@ static void ip_tunnel_dev_free(struct net_device *dev)
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);
}
@ -1049,8 +1059,21 @@ int ip_tunnel_init(struct net_device *dev)
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;
}
@ -1061,9 +1084,6 @@ int ip_tunnel_init(struct net_device *dev)
iph->version = 4;
iph->ihl = 5;
tunnel->dst_cache = NULL;
spin_lock_init(&tunnel->dst_lock);
return 0;
}
EXPORT_SYMBOL_GPL(ip_tunnel_init);
@ -1079,7 +1099,7 @@ void ip_tunnel_uninit(struct net_device *dev)
if (itn->fb_tunnel_dev != dev)
ip_tunnel_del(netdev_priv(dev));
tunnel_dst_reset(tunnel);
tunnel_dst_reset_all(tunnel);
}
EXPORT_SYMBOL_GPL(ip_tunnel_uninit);