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Commit 9a4aa9af authored by Tom Herbert's avatar Tom Herbert Committed by David S. Miller
Browse files

ipv4: Use percpu Cache route in IP tunnels 



percpu route cache eliminates share of dst refcnt between CPUs.

Signed-off-by: default avatarTom Herbert <therbert@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7d442fab

include/net/ip_tunnels.h

+6 −2
Original line number Diff line number Diff line
@@ -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;

net/ipv4/ip_tunnel.c

+32 −12
Original line number Diff line number Diff line
@@ -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);