From: Patrick McHardy Date: Thu, 31 Jan 2008 12:40:52 +0000 (-0800) Subject: [NETFILTER]: nf_conntrack: optimize hash_conntrack() X-Git-Tag: v2.6.25-rc1~1089^2~61 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0794935e21a18e7c171b604c31219b60ad9749a9;p=linux-2.6 [NETFILTER]: nf_conntrack: optimize hash_conntrack() Avoid calling jhash three times and hash the entire tuple in one go. __hash_conntrack | -485 # 760 -> 275, # inlines: 3 -> 1, size inlines: 717 -> 252 1 function changed, 485 bytes removed Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index ce4c4ba31c..4a2cce1e1c 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -73,15 +73,19 @@ static unsigned int nf_conntrack_hash_rnd; static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple, unsigned int size, unsigned int rnd) { - unsigned int a, b; + unsigned int n; + u_int32_t h; - a = jhash2(tuple->src.u3.all, ARRAY_SIZE(tuple->src.u3.all), - (tuple->src.l3num << 16) | tuple->dst.protonum); - b = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all), - ((__force __u16)tuple->src.u.all << 16) | - (__force __u16)tuple->dst.u.all); + /* The direction must be ignored, so we hash everything up to the + * destination ports (which is a multiple of 4) and treat the last + * three bytes manually. + */ + n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32); + h = jhash2((u32 *)tuple, n, + rnd ^ (((__force __u16)tuple->dst.u.all << 16) | + tuple->dst.protonum)); - return ((u64)jhash_2words(a, b, rnd) * size) >> 32; + return ((u64)h * size) >> 32; } static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)