diff options
author | Pavel Emelyanov <xemul@openvz.org> | 2008-06-16 17:14:11 -0700 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2008-06-16 17:14:11 -0700 |
commit | 0b4419162aa6c4204843f3a13b48d9ab821d3167 (patch) | |
tree | 1c475a8f59b7fce528eb97c6709b25145c110c33 | |
parent | 33de014c63646f69f36f3673e3b4676f931dc878 (diff) | |
download | linux-stable-0b4419162aa6c4204843f3a13b48d9ab821d3167.tar.gz linux-stable-0b4419162aa6c4204843f3a13b48d9ab821d3167.tar.bz2 linux-stable-0b4419162aa6c4204843f3a13b48d9ab821d3167.zip |
netns: introduce the net_hash_mix "salt" for hashes
There are many possible ways to add this "salt", thus I made this
patch to be the last in the series to change it if required.
Currently I propose to use the struct net pointer itself as this
salt, but since this pointer is most often cache-line aligned, shift
this right to eliminate the bits, that are most often zeroed.
After this, simply add this mix to prepared hashfn-s.
For CONFIG_NET_NS=n case this salt is 0 and no changes in hashfn
appear.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r-- | include/linux/udp.h | 3 | ||||
-rw-r--r-- | include/net/inet6_hashtables.h | 3 | ||||
-rw-r--r-- | include/net/inet_hashtables.h | 5 | ||||
-rw-r--r-- | include/net/inet_sock.h | 3 | ||||
-rw-r--r-- | include/net/netns/hash.h | 21 |
5 files changed, 30 insertions, 5 deletions
diff --git a/include/linux/udp.h b/include/linux/udp.h index 3deccac2e815..0cf5c4c0ec81 100644 --- a/include/linux/udp.h +++ b/include/linux/udp.h @@ -38,6 +38,7 @@ struct udphdr { #ifdef __KERNEL__ #include <net/inet_sock.h> #include <linux/skbuff.h> +#include <net/netns/hash.h> static inline struct udphdr *udp_hdr(const struct sk_buff *skb) { @@ -48,7 +49,7 @@ static inline struct udphdr *udp_hdr(const struct sk_buff *skb) static inline int udp_hashfn(struct net *net, const unsigned num) { - return num & (UDP_HTABLE_SIZE - 1); + return (num + net_hash_mix(net)) & (UDP_HTABLE_SIZE - 1); } struct udp_sock { diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h index 72f13a9928e4..e48989f04c24 100644 --- a/include/net/inet6_hashtables.h +++ b/include/net/inet6_hashtables.h @@ -24,6 +24,7 @@ #include <net/inet_sock.h> #include <net/ipv6.h> +#include <net/netns/hash.h> struct inet_hashinfo; @@ -36,7 +37,7 @@ static inline unsigned int inet6_ehashfn(struct net *net, return jhash_3words((__force u32)laddr->s6_addr32[3], (__force u32)faddr->s6_addr32[3], - ports, inet_ehash_secret); + ports, inet_ehash_secret + net_hash_mix(net)); } static inline int inet6_sk_ehashfn(const struct sock *sk) diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h index 26336cdcdc11..bb619d80f2e2 100644 --- a/include/net/inet_hashtables.h +++ b/include/net/inet_hashtables.h @@ -29,6 +29,7 @@ #include <net/inet_sock.h> #include <net/sock.h> #include <net/tcp_states.h> +#include <net/netns/hash.h> #include <asm/atomic.h> #include <asm/byteorder.h> @@ -204,7 +205,7 @@ extern void inet_bind_bucket_destroy(struct kmem_cache *cachep, static inline int inet_bhashfn(struct net *net, const __u16 lport, const int bhash_size) { - return lport & (bhash_size - 1); + return (lport + net_hash_mix(net)) & (bhash_size - 1); } extern void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, @@ -213,7 +214,7 @@ extern void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, /* These can have wildcards, don't try too hard. */ static inline int inet_lhashfn(struct net *net, const unsigned short num) { - return num & (INET_LHTABLE_SIZE - 1); + return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1); } static inline int inet_sk_listen_hashfn(const struct sock *sk) diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index 85bb420c5d86..643e26be058e 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -25,6 +25,7 @@ #include <net/sock.h> #include <net/request_sock.h> #include <net/route.h> +#include <net/netns/hash.h> /** struct ip_options - IP Options * @@ -178,7 +179,7 @@ static inline unsigned int inet_ehashfn(struct net *net, return jhash_3words((__force __u32) laddr, (__force __u32) faddr, ((__u32) lport) << 16 | (__force __u32)fport, - inet_ehash_secret); + inet_ehash_secret + net_hash_mix(net)); } static inline int inet_sk_ehashfn(const struct sock *sk) diff --git a/include/net/netns/hash.h b/include/net/netns/hash.h new file mode 100644 index 000000000000..548d78f2cc47 --- /dev/null +++ b/include/net/netns/hash.h @@ -0,0 +1,21 @@ +#ifndef __NET_NS_HASH_H__ +#define __NET_NS_HASH_H__ + +#include <asm/cache.h> + +struct net; + +static inline unsigned net_hash_mix(struct net *net) +{ +#ifdef CONFIG_NET_NS + /* + * shift this right to eliminate bits, that are + * always zeroed + */ + + return (unsigned)(((unsigned long)net) >> L1_CACHE_SHIFT); +#else + return 0; +#endif +} +#endif |