From 255d0dc34068a976550ce555e153c0bfcfec7cc6 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 18 Dec 2010 18:35:15 +0100 Subject: netfilter: x_table: speedup compat operations One iptables invocation with 135000 rules takes 35 seconds of cpu time on a recent server, using a 32bit distro and a 64bit kernel. We eventually trigger NMI/RCU watchdog. INFO: rcu_sched_state detected stall on CPU 3 (t=6000 jiffies) COMPAT mode has quadratic behavior and consume 16 bytes of memory per rule. Switch the xt_compat algos to use an array instead of list, and use a binary search to locate an offset in the sorted array. This halves memory need (8 bytes per rule), and removes quadratic behavior [ O(N*N) -> O(N*log2(N)) ] Time of iptables goes from 35 s to 150 ms. Signed-off-by: Eric Dumazet Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/ebtables.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/bridge/netfilter/ebtables.c') diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 16df0532d4b..5f1825df9dc 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1764,6 +1764,7 @@ static int compat_table_info(const struct ebt_table_info *info, newinfo->entries_size = size; + xt_compat_init_offsets(AF_INET, info->nentries); return EBT_ENTRY_ITERATE(entries, size, compat_calc_entry, info, entries, newinfo); } -- cgit v1.2.3