From ebc0ffae5dfb4447e0a431ffe7fe1d467c48bbb9 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 5 Oct 2010 10:41:36 +0000 Subject: 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 --- net/ipv4/fib_frontend.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) (limited to 'net/ipv4/fib_frontend.c') diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index b05c23b05a9f..919f2ad19b49 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(); } } -- cgit v1.2.3