From ebc0ffae5dfb4447e0a431ffe7fe1d467c48bbb9 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 5 Oct 2010 10:41:36 +0000 Subject: [PATCH] fib: RCU conversion of fib_lookup() fib_lookup() converted to be called in RCU protected context, no reference taken and released on a contended cache line (fib_clntref) fib_table_lookup() and fib_semantic_match() get an additional parameter. struct fib_info gets an rcu_head field, and is freed after an rcu grace period. Stress test : (Sending 160.000.000 UDP frames on same neighbour, IP route cache disabled, dual E5540 @2.53GHz, 32bit kernel, FIB_HASH) (about same results for FIB_TRIE) Before patch : real 1m31.199s user 0m13.761s sys 23m24.780s After patch: real 1m5.375s user 0m14.997s sys 15m50.115s Before patch Profile : 13044.00 15.4% __ip_route_output_key vmlinux 8438.00 10.0% dst_destroy vmlinux 5983.00 7.1% fib_semantic_match vmlinux 5410.00 6.4% fib_rules_lookup vmlinux 4803.00 5.7% neigh_lookup vmlinux 4420.00 5.2% _raw_spin_lock vmlinux 3883.00 4.6% rt_set_nexthop vmlinux 3261.00 3.9% _raw_read_lock vmlinux 2794.00 3.3% fib_table_lookup vmlinux 2374.00 2.8% neigh_resolve_output vmlinux 2153.00 2.5% dst_alloc vmlinux 1502.00 1.8% _raw_read_lock_bh vmlinux 1484.00 1.8% kmem_cache_alloc vmlinux 1407.00 1.7% eth_header vmlinux 1406.00 1.7% ipv4_dst_destroy vmlinux 1298.00 1.5% __copy_from_user_ll vmlinux 1174.00 1.4% dev_queue_xmit vmlinux 1000.00 1.2% ip_output vmlinux After patch Profile : 13712.00 15.8% dst_destroy vmlinux 8548.00 9.9% __ip_route_output_key vmlinux 7017.00 8.1% neigh_lookup vmlinux 4554.00 5.3% fib_semantic_match vmlinux 4067.00 4.7% _raw_read_lock vmlinux 3491.00 4.0% dst_alloc vmlinux 3186.00 3.7% neigh_resolve_output vmlinux 3103.00 3.6% fib_table_lookup vmlinux 2098.00 2.4% _raw_read_lock_bh vmlinux 2081.00 2.4% kmem_cache_alloc vmlinux 2013.00 2.3% _raw_spin_lock vmlinux 1763.00 2.0% __copy_from_user_ll vmlinux 1763.00 2.0% ip_output vmlinux 1761.00 2.0% ipv4_dst_destroy vmlinux 1631.00 1.9% eth_header vmlinux 1440.00 1.7% _raw_read_unlock_bh vmlinux Reference results, if IP route cache is enabled : real 0m29.718s user 0m10.845s sys 7m37.341s 25213.00 29.5% __ip_route_output_key vmlinux 9011.00 10.5% dst_release vmlinux 4817.00 5.6% ip_push_pending_frames vmlinux 4232.00 5.0% ip_finish_output vmlinux 3940.00 4.6% udp_sendmsg vmlinux 3730.00 4.4% __copy_from_user_ll vmlinux 3716.00 4.4% ip_route_output_flow vmlinux 2451.00 2.9% __xfrm_lookup vmlinux 2221.00 2.6% ip_append_data vmlinux 1718.00 2.0% _raw_spin_lock_bh vmlinux 1655.00 1.9% __alloc_skb vmlinux 1572.00 1.8% sock_wfree vmlinux 1345.00 1.6% kfree vmlinux Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/fib_rules.h | 2 ++ include/net/ip_fib.h | 17 +++--------- net/core/fib_rules.c | 3 +- net/ipv4/fib_frontend.c | 27 +++++++++--------- net/ipv4/fib_hash.c | 5 ++-- net/ipv4/fib_lookup.h | 2 +- net/ipv4/fib_rules.c | 3 +- net/ipv4/fib_semantics.c | 21 ++++++++++---- net/ipv4/fib_trie.c | 10 +++---- net/ipv4/route.c | 59 ++++++++++++++++------------------------ 10 files changed, 72 insertions(+), 77 deletions(-) diff --git a/include/net/fib_rules.h b/include/net/fib_rules.h index ac2fd002812..106f3097d38 100644 --- a/include/net/fib_rules.h +++ b/include/net/fib_rules.h @@ -31,6 +31,8 @@ struct fib_lookup_arg { void *lookup_ptr; void *result; struct fib_rule *rule; + int flags; +#define FIB_LOOKUP_NOREF 1 }; struct fib_rules_ops { diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h index c93f94edc61..ba3666d3176 100644 --- a/include/net/ip_fib.h +++ b/include/net/ip_fib.h @@ -86,6 +86,7 @@ struct fib_info { #ifdef CONFIG_IP_ROUTE_MULTIPATH int fib_power; #endif + struct rcu_head rcu; struct fib_nh fib_nh[0]; #define fib_dev fib_nh[0].nh_dev }; @@ -148,7 +149,7 @@ struct fib_table { }; extern int fib_table_lookup(struct fib_table *tb, const struct flowi *flp, - struct fib_result *res); + struct fib_result *res, int fib_flags); extern int fib_table_insert(struct fib_table *, struct fib_config *); extern int fib_table_delete(struct fib_table *, struct fib_config *); extern int fib_table_dump(struct fib_table *table, struct sk_buff *skb, @@ -185,11 +186,11 @@ static inline int fib_lookup(struct net *net, const struct flowi *flp, struct fib_table *table; table = fib_get_table(net, RT_TABLE_LOCAL); - if (!fib_table_lookup(table, flp, res)) + if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF)) return 0; table = fib_get_table(net, RT_TABLE_MAIN); - if (!fib_table_lookup(table, flp, res)) + if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF)) return 0; return -ENETUNREACH; } @@ -254,16 +255,6 @@ static inline void fib_info_put(struct fib_info *fi) free_fib_info(fi); } -static inline void fib_res_put(struct fib_result *res) -{ - if (res->fi) - fib_info_put(res->fi); -#ifdef CONFIG_IP_MULTIPLE_TABLES - if (res->r) - fib_rule_put(res->r); -#endif -} - #ifdef CONFIG_PROC_FS extern int __net_init fib_proc_init(struct net *net); extern void __net_exit fib_proc_exit(struct net *net); diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c index cfb7d25c172..21698f8c49e 100644 --- a/net/core/fib_rules.c +++ b/net/core/fib_rules.c @@ -225,7 +225,8 @@ jumped: err = ops->action(rule, fl, flags, arg); if (err != -EAGAIN) { - if (likely(atomic_inc_not_zero(&rule->refcnt))) { + if ((arg->flags & FIB_LOOKUP_NOREF) || + likely(atomic_inc_not_zero(&rule->refcnt))) { arg->rule = rule; goto out; } diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index b05c23b05a9..919f2ad19b4 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -168,8 +168,11 @@ struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref) struct fib_result res = { 0 }; struct net_device *dev = NULL; - if (fib_lookup(net, &fl, &res)) + rcu_read_lock(); + if (fib_lookup(net, &fl, &res)) { + rcu_read_unlock(); return NULL; + } if (res.type != RTN_LOCAL) goto out; dev = FIB_RES_DEV(res); @@ -177,7 +180,7 @@ struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref) if (dev && devref) dev_hold(dev); out: - fib_res_put(&res); + rcu_read_unlock(); return dev; } EXPORT_SYMBOL(__ip_dev_find); @@ -207,11 +210,12 @@ static inline unsigned __inet_dev_addr_type(struct net *net, local_table = fib_get_table(net, RT_TABLE_LOCAL); if (local_table) { ret = RTN_UNICAST; - if (!fib_table_lookup(local_table, &fl, &res)) { + rcu_read_lock(); + if (!fib_table_lookup(local_table, &fl, &res, FIB_LOOKUP_NOREF)) { if (!dev || dev == res.fi->fib_dev) ret = res.type; - fib_res_put(&res); } + rcu_read_unlock(); } return ret; } @@ -235,6 +239,7 @@ EXPORT_SYMBOL(inet_dev_addr_type); * - figure out what "logical" interface this packet arrived * and calculate "specific destination" address. * - check, that packet arrived from expected physical interface. + * called with rcu_read_lock() */ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif, struct net_device *dev, __be32 *spec_dst, @@ -259,7 +264,6 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif, struct net *net; no_addr = rpf = accept_local = 0; - rcu_read_lock(); in_dev = __in_dev_get_rcu(dev); if (in_dev) { no_addr = in_dev->ifa_list == NULL; @@ -268,7 +272,6 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif, if (mark && !IN_DEV_SRC_VMARK(in_dev)) fl.mark = 0; } - rcu_read_unlock(); if (in_dev == NULL) goto e_inval; @@ -278,7 +281,7 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif, goto last_resort; if (res.type != RTN_UNICAST) { if (res.type != RTN_LOCAL || !accept_local) - goto e_inval_res; + goto e_inval; } *spec_dst = FIB_RES_PREFSRC(res); fib_combine_itag(itag, &res); @@ -299,10 +302,8 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif, #endif if (dev_match) { ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST; - fib_res_put(&res); return ret; } - fib_res_put(&res); if (no_addr) goto last_resort; if (rpf == 1) @@ -315,7 +316,6 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif, *spec_dst = FIB_RES_PREFSRC(res); ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST; } - fib_res_put(&res); } return ret; @@ -326,8 +326,6 @@ last_resort: *itag = 0; return 0; -e_inval_res: - fib_res_put(&res); e_inval: return -EINVAL; e_rpf: @@ -873,15 +871,16 @@ static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb) local_bh_disable(); frn->tb_id = tb->tb_id; - frn->err = fib_table_lookup(tb, &fl, &res); + rcu_read_lock(); + frn->err = fib_table_lookup(tb, &fl, &res, FIB_LOOKUP_NOREF); if (!frn->err) { frn->prefixlen = res.prefixlen; frn->nh_sel = res.nh_sel; frn->type = res.type; frn->scope = res.scope; - fib_res_put(&res); } + rcu_read_unlock(); local_bh_enable(); } } diff --git a/net/ipv4/fib_hash.c b/net/ipv4/fib_hash.c index 4ed7e0dea1b..83cca68e259 100644 --- a/net/ipv4/fib_hash.c +++ b/net/ipv4/fib_hash.c @@ -244,7 +244,8 @@ fn_new_zone(struct fn_hash *table, int z) } int fib_table_lookup(struct fib_table *tb, - const struct flowi *flp, struct fib_result *res) + const struct flowi *flp, struct fib_result *res, + int fib_flags) { int err; struct fn_zone *fz; @@ -264,7 +265,7 @@ int fib_table_lookup(struct fib_table *tb, err = fib_semantic_match(&f->fn_alias, flp, res, - fz->fz_order); + fz->fz_order, fib_flags); if (err <= 0) goto out; } diff --git a/net/ipv4/fib_lookup.h b/net/ipv4/fib_lookup.h index 637b133973b..b9c9a9f2aee 100644 --- a/net/ipv4/fib_lookup.h +++ b/net/ipv4/fib_lookup.h @@ -22,7 +22,7 @@ struct fib_alias { /* Exported by fib_semantics.c */ extern int fib_semantic_match(struct list_head *head, const struct flowi *flp, - struct fib_result *res, int prefixlen); + struct fib_result *res, int prefixlen, int fib_flags); extern void fib_release_info(struct fib_info *); extern struct fib_info *fib_create_info(struct fib_config *cfg); extern int fib_nh_match(struct fib_config *cfg, struct fib_info *fi); diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c index 32300521e32..7981a24f5c7 100644 --- a/net/ipv4/fib_rules.c +++ b/net/ipv4/fib_rules.c @@ -57,6 +57,7 @@ int fib_lookup(struct net *net, struct flowi *flp, struct fib_result *res) { struct fib_lookup_arg arg = { .result = res, + .flags = FIB_LOOKUP_NOREF, }; int err; @@ -94,7 +95,7 @@ static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp, if (!tbl) goto errout; - err = fib_table_lookup(tbl, flp, (struct fib_result *) arg->result); + err = fib_table_lookup(tbl, flp, (struct fib_result *) arg->result, arg->flags); if (err > 0) err = -EAGAIN; errout: diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index ba52f399a89..0f80dfc2f7f 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -148,6 +148,13 @@ static const struct /* Release a nexthop info record */ +static void free_fib_info_rcu(struct rcu_head *head) +{ + struct fib_info *fi = container_of(head, struct fib_info, rcu); + + kfree(fi); +} + void free_fib_info(struct fib_info *fi) { if (fi->fib_dead == 0) { @@ -161,7 +168,7 @@ void free_fib_info(struct fib_info *fi) } endfor_nexthops(fi); fib_info_cnt--; release_net(fi->fib_net); - kfree(fi); + call_rcu(&fi->rcu, free_fib_info_rcu); } void fib_release_info(struct fib_info *fi) @@ -553,6 +560,7 @@ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, nh->nh_scope = RT_SCOPE_LINK; return 0; } + rcu_read_lock(); { struct flowi fl = { .nl_u = { @@ -568,8 +576,10 @@ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, if (fl.fl4_scope < RT_SCOPE_LINK) fl.fl4_scope = RT_SCOPE_LINK; err = fib_lookup(net, &fl, &res); - if (err) + if (err) { + rcu_read_unlock(); return err; + } } err = -EINVAL; if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) @@ -585,7 +595,7 @@ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, goto out; err = 0; out: - fib_res_put(&res); + rcu_read_unlock(); return err; } else { struct in_device *in_dev; @@ -879,7 +889,7 @@ failure: /* Note! fib_semantic_match intentionally uses RCU list functions. */ int fib_semantic_match(struct list_head *head, const struct flowi *flp, - struct fib_result *res, int prefixlen) + struct fib_result *res, int prefixlen, int fib_flags) { struct fib_alias *fa; int nh_sel = 0; @@ -943,7 +953,8 @@ out_fill_res: res->type = fa->fa_type; res->scope = fa->fa_scope; res->fi = fa->fa_info; - atomic_inc(&res->fi->fib_clntref); + if (!(fib_flags & FIB_LOOKUP_NOREF)) + atomic_inc(&res->fi->fib_clntref); return 0; } diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index a96e5ec211a..271c89bdf04 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -1342,7 +1342,7 @@ err: /* should be called with rcu_read_lock */ static int check_leaf(struct trie *t, struct leaf *l, t_key key, const struct flowi *flp, - struct fib_result *res) + struct fib_result *res, int fib_flags) { struct leaf_info *li; struct hlist_head *hhead = &l->list; @@ -1356,7 +1356,7 @@ static int check_leaf(struct trie *t, struct leaf *l, if (l->key != (key & ntohl(mask))) continue; - err = fib_semantic_match(&li->falh, flp, res, plen); + err = fib_semantic_match(&li->falh, flp, res, plen, fib_flags); #ifdef CONFIG_IP_FIB_TRIE_STATS if (err <= 0) @@ -1372,7 +1372,7 @@ static int check_leaf(struct trie *t, struct leaf *l, } int fib_table_lookup(struct fib_table *tb, const struct flowi *flp, - struct fib_result *res) + struct fib_result *res, int fib_flags) { struct trie *t = (struct trie *) tb->tb_data; int ret; @@ -1399,7 +1399,7 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi *flp, /* Just a leaf? */ if (IS_LEAF(n)) { - ret = check_leaf(t, (struct leaf *)n, key, flp, res); + ret = check_leaf(t, (struct leaf *)n, key, flp, res, fib_flags); goto found; } @@ -1424,7 +1424,7 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi *flp, } if (IS_LEAF(n)) { - ret = check_leaf(t, (struct leaf *)n, key, flp, res); + ret = check_leaf(t, (struct leaf *)n, key, flp, res, fib_flags); if (ret > 0) goto backtrace; goto found; diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 04e0df82b88..7864d0c4896 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1773,12 +1773,15 @@ void ip_rt_get_source(u8 *addr, struct rtable *rt) if (rt->fl.iif == 0) src = rt->rt_src; - else if (fib_lookup(dev_net(rt->dst.dev), &rt->fl, &res) == 0) { - src = FIB_RES_PREFSRC(res); - fib_res_put(&res); - } else - src = inet_select_addr(rt->dst.dev, rt->rt_gateway, + else { + rcu_read_lock(); + if (fib_lookup(dev_net(rt->dst.dev), &rt->fl, &res) == 0) + src = FIB_RES_PREFSRC(res); + else + src = inet_select_addr(rt->dst.dev, rt->rt_gateway, RT_SCOPE_UNIVERSE); + rcu_read_unlock(); + } memcpy(addr, &src, 4); } @@ -2081,6 +2084,7 @@ static int ip_mkroute_input(struct sk_buff *skb, * Such approach solves two big problems: * 1. Not simplex devices are handled properly. * 2. IP spoofing attempts are filtered with 100% of guarantee. + * called with rcu_read_lock() */ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, @@ -2102,7 +2106,6 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, unsigned hash; __be32 spec_dst; int err = -EINVAL; - int free_res = 0; struct net * net = dev_net(dev); /* IP on this device is disabled. */ @@ -2134,12 +2137,12 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, /* * Now we are ready to route packet. */ - if ((err = fib_lookup(net, &fl, &res)) != 0) { + err = fib_lookup(net, &fl, &res); + if (err != 0) { if (!IN_DEV_FORWARD(in_dev)) goto e_hostunreach; goto no_route; } - free_res = 1; RT_CACHE_STAT_INC(in_slow_tot); @@ -2148,8 +2151,8 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, if (res.type == RTN_LOCAL) { err = fib_validate_source(saddr, daddr, tos, - net->loopback_dev->ifindex, - dev, &spec_dst, &itag, skb->mark); + net->loopback_dev->ifindex, + dev, &spec_dst, &itag, skb->mark); if (err < 0) goto martian_source_keep_err; if (err) @@ -2164,9 +2167,6 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, goto martian_destination; err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos); -done: - if (free_res) - fib_res_put(&res); out: return err; brd_input: @@ -2226,7 +2226,7 @@ local_input: rth->rt_type = res.type; hash = rt_hash(daddr, saddr, fl.iif, rt_genid(net)); err = rt_intern_hash(hash, rth, NULL, skb, fl.iif); - goto done; + goto out; no_route: RT_CACHE_STAT_INC(in_no_route); @@ -2249,21 +2249,21 @@ martian_destination: e_hostunreach: err = -EHOSTUNREACH; - goto done; + goto out; e_inval: err = -EINVAL; - goto done; + goto out; e_nobufs: err = -ENOBUFS; - goto done; + goto out; martian_source: err = -EINVAL; martian_source_keep_err: ip_handle_martian_source(dev, in_dev, skb, daddr, saddr); - goto done; + goto out; } int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr, @@ -2349,6 +2349,7 @@ skip_cache: } EXPORT_SYMBOL(ip_route_input_common); +/* called with rcu_read_lock() */ static int __mkroute_output(struct rtable **result, struct fib_result *res, const struct flowi *fl, @@ -2373,18 +2374,13 @@ static int __mkroute_output(struct rtable **result, if (dev_out->flags & IFF_LOOPBACK) flags |= RTCF_LOCAL; - rcu_read_lock(); in_dev = __in_dev_get_rcu(dev_out); - if (!in_dev) { - rcu_read_unlock(); + if (!in_dev) return -EINVAL; - } + if (res->type == RTN_BROADCAST) { flags |= RTCF_BROADCAST | RTCF_LOCAL; - if (res->fi) { - fib_info_put(res->fi); - res->fi = NULL; - } + res->fi = NULL; } else if (res->type == RTN_MULTICAST) { flags |= RTCF_MULTICAST | RTCF_LOCAL; if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src, @@ -2394,10 +2390,8 @@ static int __mkroute_output(struct rtable **result, * default one, but do not gateway in this case. * Yes, it is hack. */ - if (res->fi && res->prefixlen < 4) { - fib_info_put(res->fi); + if (res->fi && res->prefixlen < 4) res->fi = NULL; - } } @@ -2467,6 +2461,7 @@ static int __mkroute_output(struct rtable **result, return 0; } +/* called with rcu_read_lock() */ static int ip_mkroute_output(struct rtable **rp, struct fib_result *res, const struct flowi *fl, @@ -2509,7 +2504,6 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp, struct fib_result res; unsigned int flags = 0; struct net_device *dev_out = NULL; - int free_res = 0; int err; @@ -2636,15 +2630,12 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp, err = -ENETUNREACH; goto out; } - free_res = 1; if (res.type == RTN_LOCAL) { if (!fl.fl4_src) fl.fl4_src = fl.fl4_dst; dev_out = net->loopback_dev; fl.oif = dev_out->ifindex; - if (res.fi) - fib_info_put(res.fi); res.fi = NULL; flags |= RTCF_LOCAL; goto make_route; @@ -2668,8 +2659,6 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp, make_route: err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags); - if (free_res) - fib_res_put(&res); out: return err; } -- 2.39.3