From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: [PATCH 5/6] IPV4: route use jhash3 Date: Mon, 31 Mar 2008 17:47:13 -0700 Message-ID: <20080401004724.752793269@vyatta.com> References: <20080401004708.009204033@vyatta.com> Cc: netdev@vger.kernel.org To: "David S. Miller" Return-path: Received: from suva.vyatta.com ([69.59.150.140]:40014 "EHLO suva.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755349AbYDACbe (ORCPT ); Mon, 31 Mar 2008 22:31:34 -0400 Content-Disposition: inline; filename=route-jhash3 Sender: netdev-owner@vger.kernel.org List-ID: Since route hash is a triple, use jhash_3words rather doing the mixing directly. This should be as fast and give better distribution. Signed-off-by: Stephen Hemminger --- a/net/ipv4/route.c 2008-03-31 11:14:50.000000000 -0700 +++ b/net/ipv4/route.c 2008-03-31 11:15:20.000000000 -0700 @@ -259,16 +259,14 @@ static DEFINE_PER_CPU(struct rt_cache_st #define RT_CACHE_STAT_INC(field) \ (__raw_get_cpu_var(rt_cache_stat).field++) -static unsigned int rt_hash_code(u32 daddr, u32 saddr) +static inline unsigned int rt_hash(__be32 daddr, __be32 saddr, int idx) { - return jhash_2words(daddr, saddr, atomic_read(&rt_genid)) - & rt_hash_mask; + return jhash_3words((__force u32)(__be32)(daddr), + (__force u32)(__be32)(saddr), + idx, atomic_read(&rt_genid)) + & rt_hash_mask; } -#define rt_hash(daddr, saddr, idx) \ - rt_hash_code((__force u32)(__be32)(daddr),\ - (__force u32)(__be32)(saddr) ^ ((idx) << 5)) - #ifdef CONFIG_PROC_FS struct rt_cache_iter_state { struct seq_net_private p; --