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 <pablo@xxxxxxxxxxxxx>
---
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 @@ nft_do_chain(struct nft_pktinfo *pkt, void *priv)
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;
}
--
2.1.4
--
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