From 1442e7507dd597cc701b224d3cc9bf1f165e928b Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Wed, 12 Mar 2014 23:49:49 +0100 Subject: [PATCH] netfilter: connlimit: use keyed locks connlimit currently suffers from spinlock contention, example for 4-core system with rps enabled: + 20.84% ksoftirqd/2 [kernel.kallsyms] [k] _raw_spin_lock_bh + 20.76% ksoftirqd/1 [kernel.kallsyms] [k] _raw_spin_lock_bh + 20.42% ksoftirqd/0 [kernel.kallsyms] [k] _raw_spin_lock_bh + 6.07% ksoftirqd/2 [nf_conntrack] [k] ____nf_conntrack_find + 6.07% ksoftirqd/1 [nf_conntrack] [k] ____nf_conntrack_find + 5.97% ksoftirqd/0 [nf_conntrack] [k] ____nf_conntrack_find + 2.47% ksoftirqd/2 [nf_conntrack] [k] hash_conntrack_raw + 2.45% ksoftirqd/0 [nf_conntrack] [k] hash_conntrack_raw + 2.44% ksoftirqd/1 [nf_conntrack] [k] hash_conntrack_raw May allow parallel lookup/insert/delete if the entry is hashed to another slot. With patch: + 20.95% ksoftirqd/0 [nf_conntrack] [k] ____nf_conntrack_find + 20.50% ksoftirqd/1 [nf_conntrack] [k] ____nf_conntrack_find + 20.27% ksoftirqd/2 [nf_conntrack] [k] ____nf_conntrack_find + 5.76% ksoftirqd/1 [nf_conntrack] [k] hash_conntrack_raw + 5.39% ksoftirqd/2 [nf_conntrack] [k] hash_conntrack_raw + 5.35% ksoftirqd/0 [nf_conntrack] [k] hash_conntrack_raw + 2.00% ksoftirqd/1 [kernel.kallsyms] [k] __rcu_read_unlock Improved rx processing rate from ~35kpps to ~50 kpps. Reviewed-by: Jesper Dangaard Brouer Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/xt_connlimit.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) diff --git a/net/netfilter/xt_connlimit.c b/net/netfilter/xt_connlimit.c index a8eaabb03be..ad290cc1f69 100644 --- a/net/netfilter/xt_connlimit.c +++ b/net/netfilter/xt_connlimit.c @@ -31,6 +31,9 @@ #include #include +#define CONNLIMIT_SLOTS 256 +#define CONNLIMIT_LOCK_SLOTS 32 + /* we will save the tuples of all connections we care about */ struct xt_connlimit_conn { struct hlist_node node; @@ -39,8 +42,8 @@ struct xt_connlimit_conn { }; struct xt_connlimit_data { - struct hlist_head iphash[256]; - spinlock_t lock; + struct hlist_head iphash[CONNLIMIT_SLOTS]; + spinlock_t locks[CONNLIMIT_LOCK_SLOTS]; }; static u_int32_t connlimit_rnd __read_mostly; @@ -48,7 +51,8 @@ static struct kmem_cache *connlimit_conn_cachep __read_mostly; static inline unsigned int connlimit_iphash(__be32 addr) { - return jhash_1word((__force __u32)addr, connlimit_rnd) & 0xFF; + return jhash_1word((__force __u32)addr, + connlimit_rnd) % CONNLIMIT_SLOTS; } static inline unsigned int @@ -61,7 +65,8 @@ connlimit_iphash6(const union nf_inet_addr *addr, for (i = 0; i < ARRAY_SIZE(addr->ip6); ++i) res.ip6[i] = addr->ip6[i] & mask->ip6[i]; - return jhash2((u32 *)res.ip6, ARRAY_SIZE(res.ip6), connlimit_rnd) & 0xFF; + return jhash2((u32 *)res.ip6, ARRAY_SIZE(res.ip6), + connlimit_rnd) % CONNLIMIT_SLOTS; } static inline bool already_closed(const struct nf_conn *conn) @@ -183,7 +188,7 @@ static int count_them(struct net *net, hhead = &data->iphash[hash]; - spin_lock_bh(&data->lock); + spin_lock_bh(&data->locks[hash % CONNLIMIT_LOCK_SLOTS]); count = count_hlist(net, hhead, tuple, addr, mask, family, &addit); if (addit) { if (add_hlist(hhead, tuple, addr)) @@ -191,7 +196,7 @@ static int count_them(struct net *net, else count = -ENOMEM; } - spin_unlock_bh(&data->lock); + spin_unlock_bh(&data->locks[hash % CONNLIMIT_LOCK_SLOTS]); return count; } @@ -227,7 +232,6 @@ connlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) connections = count_them(net, info->data, tuple_ptr, &addr, &info->mask, par->family); - if (connections < 0) /* kmalloc failed, drop it entirely */ goto hotdrop; @@ -268,7 +272,9 @@ static int connlimit_mt_check(const struct xt_mtchk_param *par) return -ENOMEM; } - spin_lock_init(&info->data->lock); + for (i = 0; i < ARRAY_SIZE(info->data->locks); ++i) + spin_lock_init(&info->data->locks[i]); + for (i = 0; i < ARRAY_SIZE(info->data->iphash); ++i) INIT_HLIST_HEAD(&info->data->iphash[i]); @@ -309,6 +315,10 @@ static struct xt_match connlimit_mt_reg __read_mostly = { static int __init connlimit_mt_init(void) { int ret; + + BUILD_BUG_ON(CONNLIMIT_LOCK_SLOTS > CONNLIMIT_SLOTS); + BUILD_BUG_ON((CONNLIMIT_SLOTS % CONNLIMIT_LOCK_SLOTS) != 0); + connlimit_conn_cachep = kmem_cache_create("xt_connlimit_conn", sizeof(struct xt_connlimit_conn), 0, 0, NULL); -- 2.46.0