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linux/fs/ceph/crush/hash.h

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ceph: CRUSH mapping algorithm CRUSH is a pseudorandom data distribution function designed to map inputs onto a dynamic hierarchy of devices, while minimizing the extent to which inputs are remapped when the devices are added or removed. It includes some features that are specifically useful for storage, most notably the ability to map each input onto a set of N devices that are separated across administrator-defined failure domains. CRUSH is used to distribute data across the cluster of Ceph storage nodes. More information about CRUSH can be found in this paper: http://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-06 11:31:11 -07:00
#ifndef _CRUSH_HASH_H
#define _CRUSH_HASH_H
ceph: make CRUSH hash function a bucket property Make the integer hash function a property of the bucket it is used on. This allows us to gracefully add support for new hash functions without starting from scatch. Signed-off-by: Sage Weil <sage@newdream.net>
2009-11-07 21:18:22 -07:00
#define CRUSH_HASH_RJENKINS1 0
#define CRUSH_HASH_DEFAULT CRUSH_HASH_RJENKINS1
extern const char *crush_hash_name(int type);
extern __u32 crush_hash32(int type, __u32 a);
extern __u32 crush_hash32_2(int type, __u32 a, __u32 b);
extern __u32 crush_hash32_3(int type, __u32 a, __u32 b, __u32 c);
extern __u32 crush_hash32_4(int type, __u32 a, __u32 b, __u32 c, __u32 d);
extern __u32 crush_hash32_5(int type, __u32 a, __u32 b, __u32 c, __u32 d,
__u32 e);
ceph: CRUSH mapping algorithm CRUSH is a pseudorandom data distribution function designed to map inputs onto a dynamic hierarchy of devices, while minimizing the extent to which inputs are remapped when the devices are added or removed. It includes some features that are specifically useful for storage, most notably the ability to map each input onto a set of N devices that are separated across administrator-defined failure domains. CRUSH is used to distribute data across the cluster of Ceph storage nodes. More information about CRUSH can be found in this paper: http://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-06 11:31:11 -07:00
#endif
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