From 0b4419162aa6c4204843f3a13b48d9ab821d3167 Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Mon, 16 Jun 2008 17:14:11 -0700 Subject: 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 Signed-off-by: David S. Miller --- include/net/netns/hash.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 include/net/netns/hash.h (limited to 'include/net/netns') 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 + +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 -- cgit v1.2.3