Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit fb690390 authored by Sage Weil's avatar Sage Weil
Browse files

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: default avatarSage Weil <sage@newdream.net>
parent 1654dd0c

fs/ceph/crush/crush.h

+2 −1
Original line number Diff line number Diff line
@@ -102,7 +102,8 @@ extern const char *crush_bucket_alg_name(int alg); 
struct crush_bucket {

	__s32 id;        /* this'll be negative */

	__u16 type;      /* non-zero; type=0 is reserved for devices */

	__u16 alg;       /* one of CRUSH_BUCKET_* */

	__u8 alg;        /* one of CRUSH_BUCKET_* */

	__u8 hash;       /* which hash function to use, CRUSH_HASH_* */

	__u32 weight;    /* 16-bit fixed point */

	__u32 size;      /* num items */

	__s32 *items;

fs/ceph/crush/hash.c

+68 −5
Original line number Diff line number Diff line 


#include <linux/types.h>

#include "hash.h"



/*

 * Robert Jenkins' function for mixing 32-bit values
@@ -20,7 +21,7 @@ 


#define crush_hash_seed 1315423911



__u32 crush_hash32(__u32 a)

static __u32 crush_hash32_rjenkins1(__u32 a)

{

	__u32 hash = crush_hash_seed ^ a;

	__u32 b = a;
@@ -31,7 +32,7 @@ __u32 crush_hash32(__u32 a) 
	return hash;

}



__u32 crush_hash32_2(__u32 a, __u32 b)

static __u32 crush_hash32_rjenkins1_2(__u32 a, __u32 b)

{

	__u32 hash = crush_hash_seed ^ a ^ b;

	__u32 x = 231232;
@@ -42,7 +43,7 @@ __u32 crush_hash32_2(__u32 a, __u32 b) 
	return hash;

}



__u32 crush_hash32_3(__u32 a, __u32 b, __u32 c)

static __u32 crush_hash32_rjenkins1_3(__u32 a, __u32 b, __u32 c)

{

	__u32 hash = crush_hash_seed ^ a ^ b ^ c;

	__u32 x = 231232;
@@ -55,7 +56,7 @@ __u32 crush_hash32_3(__u32 a, __u32 b, __u32 c) 
	return hash;

}



__u32 crush_hash32_4(__u32 a, __u32 b, __u32 c, __u32 d)

static __u32 crush_hash32_rjenkins1_4(__u32 a, __u32 b, __u32 c, __u32 d)

{

	__u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d;

	__u32 x = 231232;
@@ -69,7 +70,8 @@ __u32 crush_hash32_4(__u32 a, __u32 b, __u32 c, __u32 d) 
	return hash;

}



__u32 crush_hash32_5(__u32 a, __u32 b, __u32 c, __u32 d, __u32 e)

static __u32 crush_hash32_rjenkins1_5(__u32 a, __u32 b, __u32 c, __u32 d,

				      __u32 e)

{

	__u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d ^ e;

	__u32 x = 231232;
@@ -84,3 +86,64 @@ __u32 crush_hash32_5(__u32 a, __u32 b, __u32 c, __u32 d, __u32 e) 
	crush_hashmix(y, e, hash);

	return hash;

}





__u32 crush_hash32(int type, __u32 a)

{

	switch (type) {

	case CRUSH_HASH_RJENKINS1:

		return crush_hash32_rjenkins1(a);

	default:

		return 0;

	}

}



__u32 crush_hash32_2(int type, __u32 a, __u32 b)

{

	switch (type) {

	case CRUSH_HASH_RJENKINS1:

		return crush_hash32_rjenkins1_2(a, b);

	default:

		return 0;

	}

}



__u32 crush_hash32_3(int type, __u32 a, __u32 b, __u32 c)

{

	switch (type) {

	case CRUSH_HASH_RJENKINS1:

		return crush_hash32_rjenkins1_3(a, b, c);

	default:

		return 0;

	}

}



__u32 crush_hash32_4(int type, __u32 a, __u32 b, __u32 c, __u32 d)

{

	switch (type) {

	case CRUSH_HASH_RJENKINS1:

		return crush_hash32_rjenkins1_4(a, b, c, d);

	default:

		return 0;

	}

}



__u32 crush_hash32_5(int type, __u32 a, __u32 b, __u32 c, __u32 d, __u32 e)

{

	switch (type) {

	case CRUSH_HASH_RJENKINS1:

		return crush_hash32_rjenkins1_5(a, b, c, d, e);

	default:

		return 0;

	}

}



const char *crush_hash_name(int type)

{

	switch (type) {

	case CRUSH_HASH_RJENKINS1:

		return "rjenkins1";

	default:

		return "unknown";

	}

}

fs/ceph/crush/hash.h

+12 −7
Original line number Diff line number Diff line 
#ifndef _CRUSH_HASH_H

#define _CRUSH_HASH_H



extern __u32 crush_hash32(__u32 a);

extern __u32 crush_hash32_2(__u32 a, __u32 b);

extern __u32 crush_hash32_3(__u32 a, __u32 b, __u32 c);

extern __u32 crush_hash32_4(__u32 a, __u32 b, __u32 c,

			    __u32 d);

extern __u32 crush_hash32_5(__u32 a, __u32 b, __u32 c,

			    __u32 d, __u32 e);

#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);



#endif

fs/ceph/crush/mapper.c

+9 −7
Original line number Diff line number Diff line
@@ -78,7 +78,7 @@ static int bucket_perm_choose(struct crush_bucket *bucket, 


		/* optimize common r=0 case */

		if (pr == 0) {

			s = crush_hash32_3(x, bucket->id, 0) %

			s = crush_hash32_3(bucket->hash, x, bucket->id, 0) %

				bucket->size;

			bucket->perm[0] = s;

			bucket->perm_n = 0xffff;   /* magic value, see below */
@@ -103,7 +103,7 @@ static int bucket_perm_choose(struct crush_bucket *bucket, 
		unsigned p = bucket->perm_n;

		/* no point in swapping the final entry */

		if (p < bucket->size - 1) {

			i = crush_hash32_3(x, bucket->id, p) %

			i = crush_hash32_3(bucket->hash, x, bucket->id, p) %

				(bucket->size - p);

			if (i) {

				unsigned t = bucket->perm[p + i];
@@ -138,8 +138,8 @@ static int bucket_list_choose(struct crush_bucket_list *bucket, 
	int i;



	for (i = bucket->h.size-1; i >= 0; i--) {

		__u64 w = crush_hash32_4(x, bucket->h.items[i], r,

					 bucket->h.id);

		__u64 w = crush_hash32_4(bucket->h.hash,x, bucket->h.items[i],

					 r, bucket->h.id);

		w &= 0xffff;

		dprintk("list_choose i=%d x=%d r=%d item %d weight %x "

			"sw %x rand %llx",
@@ -198,7 +198,8 @@ static int bucket_tree_choose(struct crush_bucket_tree *bucket, 
	while (!terminal(n)) {

		/* pick point in [0, w) */

		w = bucket->node_weights[n];

		t = (__u64)crush_hash32_4(x, n, r, bucket->h.id) * (__u64)w;

		t = (__u64)crush_hash32_4(bucket->h.hash, x, n, r,

					  bucket->h.id) * (__u64)w;

		t = t >> 32;



		/* descend to the left or right? */
@@ -224,7 +225,7 @@ static int bucket_straw_choose(struct crush_bucket_straw *bucket, 
	__u64 draw;



	for (i = 0; i < bucket->h.size; i++) {

		draw = crush_hash32_3(x, bucket->h.items[i], r);

		draw = crush_hash32_3(bucket->h.hash, x, bucket->h.items[i], r);

		draw &= 0xffff;

		draw *= bucket->straws[i];

		if (i == 0 || draw > high_draw) {
@@ -267,7 +268,8 @@ static int is_out(struct crush_map *map, __u32 *weight, int item, int x) 
		return 0;

	if (weight[item] == 0)

		return 1;

	if ((crush_hash32_2(x, item) & 0xffff) < weight[item])

	if ((crush_hash32_2(CRUSH_HASH_RJENKINS1, x, item) & 0xffff)

	    < weight[item])

		return 0;

	return 1;

}

fs/ceph/osdmap.c

+2 −1
Original line number Diff line number Diff line
@@ -210,7 +210,8 @@ static struct crush_map *crush_decode(void *pbyval, void *end) 
		ceph_decode_need(p, end, 4*sizeof(u32), bad);

		b->id = ceph_decode_32(p);

		b->type = ceph_decode_16(p);

		b->alg = ceph_decode_16(p);

		b->alg = ceph_decode_8(p);

		b->hash = ceph_decode_8(p);

		b->weight = ceph_decode_32(p);

		b->size = ceph_decode_32(p);