From 9a4aa9af447f784f0a47313c8dcb79ac63442cf7 Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Thu, 2 Jan 2014 11:48:33 -0800 Subject: [PATCH] ipv4: Use percpu Cache route in IP tunnels percpu route cache eliminates share of dst refcnt between CPUs. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- 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 27d756f..e2c9cff 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -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); -- 2.7.4