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Message-ID: <alpine.DEB.2.02.1312181159080.31122@tomh.mtv.corp.google.com>
Date: Wed, 18 Dec 2013 12:06:38 -0800 (PST)
From: Tom Herbert <therbert@...gle.com>
To: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 2/2 v2] net: Use percpu Cache route in IP tunnels
percpu route cache eliminates share of dst refcnt between CPUs.
Signed-off-by: Tom Herbert <therbert@...gle.com>
---
include/net/ip_tunnels.h | 8 ++++++--
net/ipv4/ip_tunnel.c | 44 ++++++++++++++++++++++++++++++++------------
2 files changed, 38 insertions(+), 14 deletions(-)
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index bde50fc..9e25b1b 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -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;
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index f9ffe38..75564fd 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -68,20 +68,21 @@ 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;
- 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)
@@ -89,12 +90,20 @@ 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();
@@ -752,7 +761,7 @@ 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);
}
@@ -868,6 +877,7 @@ 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);
}
@@ -1046,8 +1056,21 @@ 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;
}
@@ -1058,9 +1081,6 @@ 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);
@@ -1076,7 +1096,7 @@ 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);
--
1.8.5.1
--
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