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author | Pavel Emelyanov <xemul@openvz.org> | 2008-06-17 00:14:11 (GMT) |
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committer | David S. Miller <davem@davemloft.net> | 2008-06-17 00:14:11 (GMT) |
commit | 0b4419162aa6c4204843f3a13b48d9ab821d3167 (patch) | |
tree | 1c475a8f59b7fce528eb97c6709b25145c110c33 /include/net/netns | |
parent | 33de014c63646f69f36f3673e3b4676f931dc878 (diff) | |
download | linux-fsl-qoriq-0b4419162aa6c4204843f3a13b48d9ab821d3167.tar.xz |
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>
Diffstat (limited to 'include/net/netns')
-rw-r--r-- | include/net/netns/hash.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/include/net/netns/hash.h b/include/net/netns/hash.h new file mode 100644 index 0000000..548d78f --- /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 |