From 9f08ea848117ab521efcfd3e004d8e1a0edc640c Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 18 Jul 2017 20:18:09 +0200 Subject: [PATCH] netfilter: nf_tables: keep chain counters away from hot path These chain counters are only used by the iptables-compat tool, that allow users to use the x_tables extensions from the existing nf_tables framework. This patch makes nf_tables by ~5% for the general usecase, ie. native nft users, where no chain counters are used at all. Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_tables_core.h | 2 ++ net/netfilter/nf_tables_api.c | 11 +++-------- net/netfilter/nf_tables_core.c | 26 ++++++++++++++++++-------- 3 files changed, 23 insertions(+), 16 deletions(-) diff --git a/include/net/netfilter/nf_tables_core.h b/include/net/netfilter/nf_tables_core.h index 8f690effec37..424684c33771 100644 --- a/include/net/netfilter/nf_tables_core.h +++ b/include/net/netfilter/nf_tables_core.h @@ -49,6 +49,8 @@ struct nft_payload_set { }; extern const struct nft_expr_ops nft_payload_fast_ops; + +extern struct static_key_false nft_counters_enabled; extern struct static_key_false nft_trace_enabled; #endif /* _NET_NF_TABLES_CORE_H */ diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 7843efa33c59..7fbf0070aba1 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -1240,6 +1240,8 @@ static void nf_tables_chain_destroy(struct nft_chain *chain) module_put(basechain->type->owner); free_percpu(basechain->stats); + if (basechain->stats) + static_branch_dec(&nft_counters_enabled); if (basechain->ops[0].dev != NULL) dev_put(basechain->ops[0].dev); kfree(basechain); @@ -1504,14 +1506,7 @@ static int nf_tables_newchain(struct net *net, struct sock *nlsk, return PTR_ERR(stats); } basechain->stats = stats; - } else { - stats = netdev_alloc_pcpu_stats(struct nft_stats); - if (stats == NULL) { - nft_chain_release_hook(&hook); - kfree(basechain); - return -ENOMEM; - } - rcu_assign_pointer(basechain->stats, stats); + static_branch_inc(&nft_counters_enabled); } hookfn = hook.type->hooks[hook.num]; diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c index 65dbeadcb118..c5bab08b0d73 100644 --- a/net/netfilter/nf_tables_core.c +++ b/net/netfilter/nf_tables_core.c @@ -114,6 +114,22 @@ static bool nft_payload_fast_eval(const struct nft_expr *expr, return true; } +DEFINE_STATIC_KEY_FALSE(nft_counters_enabled); + +static noinline void nft_update_chain_stats(const struct nft_chain *chain, + const struct nft_pktinfo *pkt) +{ + struct nft_stats *stats; + + local_bh_disable(); + stats = this_cpu_ptr(rcu_dereference(nft_base_chain(chain)->stats)); + u64_stats_update_begin(&stats->syncp); + stats->pkts++; + stats->bytes += pkt->skb->len; + u64_stats_update_end(&stats->syncp); + local_bh_enable(); +} + struct nft_jumpstack { const struct nft_chain *chain; const struct nft_rule *rule; @@ -130,7 +146,6 @@ nft_do_chain(struct nft_pktinfo *pkt, void *priv) struct nft_regs regs; unsigned int stackptr = 0; struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE]; - struct nft_stats *stats; int rulenum; unsigned int gencursor = nft_genmask_cur(net); struct nft_traceinfo info; @@ -220,13 +235,8 @@ next_rule: nft_trace_packet(&info, basechain, NULL, -1, NFT_TRACETYPE_POLICY); - rcu_read_lock_bh(); - stats = this_cpu_ptr(rcu_dereference(nft_base_chain(basechain)->stats)); - u64_stats_update_begin(&stats->syncp); - stats->pkts++; - stats->bytes += pkt->skb->len; - u64_stats_update_end(&stats->syncp); - rcu_read_unlock_bh(); + if (static_branch_unlikely(&nft_counters_enabled)) + nft_update_chain_stats(basechain, pkt); return nft_base_chain(basechain)->policy; } -- 2.11.0