[PATCH][XFRM][v2] Replace rwlock on xfrm_policy_afinfo with rcu
From: Priyanka Jain <hidden>
Date: 2012-08-09 06:22:12
Subsystem:
networking [general], networking [ipsec], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Steffen Klassert, Herbert Xu, Linus Torvalds
xfrm_policy_afinfo is read mosly data structure. Write on xfrm_policy_afinfo is done only at the time of configuration. So rwlocks can be safely replaced with RCU. RCUs usage optimizes the performance. Signed-off-by: Priyanka Jain <redacted> --- Changes for v2: Re-spined to netdev-next & corrected indentation as suggested by David For IPSEC fwd test -On p4080ds (8-core, SMP system) Around 110% throughput increase in case of PREEMPT_RT enabled Around 5-6% throughput increase in case of PREEMPT_RT disabled -On p2020 (2-core, SMP system) Around 4-5% throughput increase in case of PREEMPT_RT disabled net/xfrm/xfrm_policy.c | 39 ++++++++++++++++++++++----------------- 1 files changed, 22 insertions(+), 17 deletions(-)
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index c5a5165..39c4943 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c@@ -42,13 +42,14 @@ static DEFINE_SPINLOCK(xfrm_policy_sk_bundle_lock); static struct dst_entry *xfrm_policy_sk_bundles; static DEFINE_RWLOCK(xfrm_policy_lock); -static DEFINE_RWLOCK(xfrm_policy_afinfo_lock); -static struct xfrm_policy_afinfo *xfrm_policy_afinfo[NPROTO]; +static DEFINE_SPINLOCK(xfrm_policy_afinfo_lock); +static struct xfrm_policy_afinfo __rcu *xfrm_policy_afinfo[NPROTO] + __read_mostly; static struct kmem_cache *xfrm_dst_cache __read_mostly; static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family); -static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo); +static inline void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo); static void xfrm_init_pmtu(struct dst_entry *dst); static int stale_bundle(struct dst_entry *dst); static int xfrm_bundle_ok(struct xfrm_dst *xdst);
@@ -2418,7 +2419,7 @@ int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo) return -EINVAL; if (unlikely(afinfo->family >= NPROTO)) return -EAFNOSUPPORT; - write_lock_bh(&xfrm_policy_afinfo_lock); + spin_lock_bh(&xfrm_policy_afinfo_lock); if (unlikely(xfrm_policy_afinfo[afinfo->family] != NULL)) err = -ENOBUFS; else {
@@ -2439,9 +2440,9 @@ int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo) dst_ops->neigh_lookup = xfrm_neigh_lookup; if (likely(afinfo->garbage_collect == NULL)) afinfo->garbage_collect = xfrm_garbage_collect_deferred; - xfrm_policy_afinfo[afinfo->family] = afinfo; + rcu_assign_pointer(xfrm_policy_afinfo[afinfo->family], afinfo); } - write_unlock_bh(&xfrm_policy_afinfo_lock); + spin_unlock_bh(&xfrm_policy_afinfo_lock); rtnl_lock(); for_each_net(net) {
@@ -2474,13 +2475,14 @@ int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo) return -EINVAL; if (unlikely(afinfo->family >= NPROTO)) return -EAFNOSUPPORT; - write_lock_bh(&xfrm_policy_afinfo_lock); + spin_lock_bh(&xfrm_policy_afinfo_lock); if (likely(xfrm_policy_afinfo[afinfo->family] != NULL)) { if (unlikely(xfrm_policy_afinfo[afinfo->family] != afinfo)) err = -EINVAL; else { struct dst_ops *dst_ops = afinfo->dst_ops; - xfrm_policy_afinfo[afinfo->family] = NULL; + rcu_assign_pointer(xfrm_policy_afinfo[afinfo->family], + NULL); dst_ops->kmem_cachep = NULL; dst_ops->check = NULL; dst_ops->negative_advice = NULL;
@@ -2488,7 +2490,8 @@ int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo) afinfo->garbage_collect = NULL; } } - write_unlock_bh(&xfrm_policy_afinfo_lock); + spin_unlock_bh(&xfrm_policy_afinfo_lock); + synchronize_rcu(); return err; } EXPORT_SYMBOL(xfrm_policy_unregister_afinfo);
@@ -2497,8 +2500,9 @@ static void __net_init xfrm_dst_ops_init(struct net *net) { struct xfrm_policy_afinfo *afinfo; - read_lock_bh(&xfrm_policy_afinfo_lock); - afinfo = xfrm_policy_afinfo[AF_INET]; + local_bh_disable(); + rcu_read_lock(); + afinfo = rcu_dereference(xfrm_policy_afinfo[AF_INET]); if (afinfo) net->xfrm.xfrm4_dst_ops = *afinfo->dst_ops; #if IS_ENABLED(CONFIG_IPV6)
@@ -2506,7 +2510,8 @@ static void __net_init xfrm_dst_ops_init(struct net *net) if (afinfo) net->xfrm.xfrm6_dst_ops = *afinfo->dst_ops; #endif - read_unlock_bh(&xfrm_policy_afinfo_lock); + rcu_read_unlock(); + local_bh_enable(); } static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family)
@@ -2514,16 +2519,16 @@ static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family) struct xfrm_policy_afinfo *afinfo; if (unlikely(family >= NPROTO)) return NULL; - read_lock(&xfrm_policy_afinfo_lock); - afinfo = xfrm_policy_afinfo[family]; + rcu_read_lock(); + afinfo = rcu_dereference(xfrm_policy_afinfo[family]); if (unlikely(!afinfo)) - read_unlock(&xfrm_policy_afinfo_lock); + rcu_read_unlock(); return afinfo; } -static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo) +static inline void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo) { - read_unlock(&xfrm_policy_afinfo_lock); + rcu_read_unlock(); } static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
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1.7.4.1