From c5038a8327b980a5b279fa193163c468011de009 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 31 Jul 2012 15:02:02 -0700 Subject: [PATCH] ipv4: Cache routes in nexthop exception entries. Signed-off-by: David S. Miller --- include/net/ip_fib.h | 1 + net/ipv4/fib_semantics.c | 39 +++++++++--------- net/ipv4/route.c | 103 ++++++++++++++++++++++++++--------------------- 3 files changed, 79 insertions(+), 64 deletions(-) diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h index e331746..926142e 100644 --- a/include/net/ip_fib.h +++ b/include/net/ip_fib.h @@ -55,6 +55,7 @@ struct fib_nh_exception { u32 fnhe_pmtu; __be32 fnhe_gw; unsigned long fnhe_expires; + struct rtable __rcu *fnhe_rth; unsigned long fnhe_stamp; }; diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index fe2ca02..da80dc1 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -140,6 +140,21 @@ const struct fib_prop fib_props[RTN_MAX + 1] = { }, }; +static void rt_fibinfo_free(struct rtable __rcu **rtp) +{ + struct rtable *rt = rcu_dereference_protected(*rtp, 1); + + if (!rt) + return; + + /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); + * because we waited an RCU grace period before calling + * free_fib_info_rcu() + */ + + dst_free(&rt->dst); +} + static void free_nh_exceptions(struct fib_nh *nh) { struct fnhe_hash_bucket *hash = nh->nh_exceptions; @@ -153,6 +168,9 @@ static void free_nh_exceptions(struct fib_nh *nh) struct fib_nh_exception *next; next = rcu_dereference_protected(fnhe->fnhe_next, 1); + + rt_fibinfo_free(&fnhe->fnhe_rth); + kfree(fnhe); fnhe = next; @@ -161,22 +179,7 @@ static void free_nh_exceptions(struct fib_nh *nh) kfree(hash); } -static void rt_nexthop_free(struct rtable __rcu **rtp) -{ - struct rtable *rt = rcu_dereference_protected(*rtp, 1); - - if (!rt) - return; - - /* Not even needed : RCU_INIT_POINTER(*rtp, NULL); - * because we waited an RCU grace period before calling - * free_fib_info_rcu() - */ - - dst_free(&rt->dst); -} - -static void rt_nexthop_free_cpus(struct rtable __rcu * __percpu *rtp) +static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp) { int cpu; @@ -203,8 +206,8 @@ static void free_fib_info_rcu(struct rcu_head *head) dev_put(nexthop_nh->nh_dev); if (nexthop_nh->nh_exceptions) free_nh_exceptions(nexthop_nh); - rt_nexthop_free_cpus(nexthop_nh->nh_pcpu_rth_output); - rt_nexthop_free(&nexthop_nh->nh_rth_input); + rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output); + rt_fibinfo_free(&nexthop_nh->nh_rth_input); } endfor_nexthops(fi); release_net(fi->fib_net); diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 4f6276c..b102eeb 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -587,11 +587,17 @@ static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk, build_sk_flow_key(fl4, sk); } -static DEFINE_SEQLOCK(fnhe_seqlock); +static inline void rt_free(struct rtable *rt) +{ + call_rcu(&rt->dst.rcu_head, dst_rcu_free); +} + +static DEFINE_SPINLOCK(fnhe_lock); static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) { struct fib_nh_exception *fnhe, *oldest; + struct rtable *orig; oldest = rcu_dereference(hash->chain); for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe; @@ -599,6 +605,11 @@ static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp)) oldest = fnhe; } + orig = rcu_dereference(oldest->fnhe_rth); + if (orig) { + RCU_INIT_POINTER(oldest->fnhe_rth, NULL); + rt_free(orig); + } return oldest; } @@ -620,7 +631,7 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, int depth; u32 hval = fnhe_hashfun(daddr); - write_seqlock_bh(&fnhe_seqlock); + spin_lock_bh(&fnhe_lock); hash = nh->nh_exceptions; if (!hash) { @@ -667,7 +678,7 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw, fnhe->fnhe_stamp = jiffies; out_unlock: - write_sequnlock_bh(&fnhe_seqlock); + spin_unlock_bh(&fnhe_lock); return; } @@ -1167,41 +1178,40 @@ static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr) static void rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe, __be32 daddr) { - __be32 fnhe_daddr, gw; - unsigned long expires; - unsigned int seq; - u32 pmtu; - -restart: - seq = read_seqbegin(&fnhe_seqlock); - fnhe_daddr = fnhe->fnhe_daddr; - gw = fnhe->fnhe_gw; - pmtu = fnhe->fnhe_pmtu; - expires = fnhe->fnhe_expires; - if (read_seqretry(&fnhe_seqlock, seq)) - goto restart; - - if (daddr != fnhe_daddr) - return; + spin_lock_bh(&fnhe_lock); - if (pmtu) { - unsigned long diff = expires - jiffies; + if (daddr == fnhe->fnhe_daddr) { + struct rtable *orig; - if (time_before(jiffies, expires)) { - rt->rt_pmtu = pmtu; - dst_set_expires(&rt->dst, diff); + if (fnhe->fnhe_pmtu) { + unsigned long expires = fnhe->fnhe_expires; + unsigned long diff = expires - jiffies; + + if (time_before(jiffies, expires)) { + rt->rt_pmtu = fnhe->fnhe_pmtu; + dst_set_expires(&rt->dst, diff); + } + } + if (fnhe->fnhe_gw) { + rt->rt_flags |= RTCF_REDIRECTED; + rt->rt_gateway = fnhe->fnhe_gw; } - } - if (gw) { - rt->rt_flags |= RTCF_REDIRECTED; - rt->rt_gateway = gw; - } - fnhe->fnhe_stamp = jiffies; -} -static inline void rt_free(struct rtable *rt) -{ - call_rcu(&rt->dst.rcu_head, dst_rcu_free); + orig = rcu_dereference(fnhe->fnhe_rth); + rcu_assign_pointer(fnhe->fnhe_rth, rt); + if (orig) + rt_free(orig); + + fnhe->fnhe_stamp = jiffies; + } else { + /* Routes we intend to cache in nexthop exception have + * the DST_NOCACHE bit clear. However, if we are + * unsuccessful at storing this route into the cache + * we really need to set it. + */ + rt->dst.flags |= DST_NOCACHE; + } + spin_unlock_bh(&fnhe_lock); } static void rt_cache_route(struct fib_nh *nh, struct rtable *rt) @@ -1249,13 +1259,13 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr, if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK) rt->rt_gateway = nh->nh_gw; - if (unlikely(fnhe)) - rt_bind_exception(rt, fnhe, daddr); dst_init_metrics(&rt->dst, fi->fib_metrics, true); #ifdef CONFIG_IP_ROUTE_CLASSID rt->dst.tclassid = nh->nh_tclassid; #endif - if (!(rt->dst.flags & DST_NOCACHE)) + if (unlikely(fnhe)) + rt_bind_exception(rt, fnhe, daddr); + else if (!(rt->dst.flags & DST_NOCACHE)) rt_cache_route(nh, rt); } @@ -1753,22 +1763,23 @@ static struct rtable *__mkroute_output(const struct fib_result *res, fnhe = NULL; if (fi) { - fnhe = find_exception(&FIB_RES_NH(*res), fl4->daddr); - if (!fnhe && FIB_RES_NH(*res).nh_pcpu_rth_output) { - struct rtable __rcu **prth; + struct rtable __rcu **prth; + fnhe = find_exception(&FIB_RES_NH(*res), fl4->daddr); + if (fnhe) + prth = &fnhe->fnhe_rth; + else prth = __this_cpu_ptr(FIB_RES_NH(*res).nh_pcpu_rth_output); - rth = rcu_dereference(*prth); - if (rt_cache_valid(rth)) { - dst_hold(&rth->dst); - return rth; - } + rth = rcu_dereference(*prth); + if (rt_cache_valid(rth)) { + dst_hold(&rth->dst); + return rth; } } rth = rt_dst_alloc(dev_out, IN_DEV_CONF_GET(in_dev, NOPOLICY), IN_DEV_CONF_GET(in_dev, NOXFRM), - fi && !fnhe); + fi); if (!rth) return ERR_PTR(-ENOBUFS); -- 2.7.4