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-rw-r--r--fs/ceph/crush/crush.c140
-rw-r--r--fs/ceph/crush/crush.h188
-rw-r--r--fs/ceph/crush/hash.h90
-rw-r--r--fs/ceph/crush/mapper.c589
-rw-r--r--fs/ceph/crush/mapper.h20
5 files changed, 1027 insertions, 0 deletions
diff --git a/fs/ceph/crush/crush.c b/fs/ceph/crush/crush.c
new file mode 100644
index 000000000000..13755cdc4fb3
--- /dev/null
+++ b/fs/ceph/crush/crush.c
@@ -0,0 +1,140 @@
1
2#ifdef __KERNEL__
3# include <linux/slab.h>
4#else
5# include <stdlib.h>
6# include <assert.h>
7# define kfree(x) do { if (x) free(x); } while (0)
8# define BUG_ON(x) assert(!(x))
9#endif
10
11#include "crush.h"
12
13/**
14 * crush_get_bucket_item_weight - Get weight of an item in given bucket
15 * @b: bucket pointer
16 * @p: item index in bucket
17 */
18int crush_get_bucket_item_weight(struct crush_bucket *b, int p)
19{
20 if (p >= b->size)
21 return 0;
22
23 switch (b->alg) {
24 case CRUSH_BUCKET_UNIFORM:
25 return ((struct crush_bucket_uniform *)b)->item_weight;
26 case CRUSH_BUCKET_LIST:
27 return ((struct crush_bucket_list *)b)->item_weights[p];
28 case CRUSH_BUCKET_TREE:
29 if (p & 1)
30 return ((struct crush_bucket_tree *)b)->node_weights[p];
31 return 0;
32 case CRUSH_BUCKET_STRAW:
33 return ((struct crush_bucket_straw *)b)->item_weights[p];
34 }
35 return 0;
36}
37
38/**
39 * crush_calc_parents - Calculate parent vectors for the given crush map.
40 * @map: crush_map pointer
41 */
42void crush_calc_parents(struct crush_map *map)
43{
44 int i, b, c;
45
46 for (b = 0; b < map->max_buckets; b++) {
47 if (map->buckets[b] == NULL)
48 continue;
49 for (i = 0; i < map->buckets[b]->size; i++) {
50 c = map->buckets[b]->items[i];
51 BUG_ON(c >= map->max_devices ||
52 c < -map->max_buckets);
53 if (c >= 0)
54 map->device_parents[c] = map->buckets[b]->id;
55 else
56 map->bucket_parents[-1-c] = map->buckets[b]->id;
57 }
58 }
59}
60
61void crush_destroy_bucket_uniform(struct crush_bucket_uniform *b)
62{
63 kfree(b->h.perm);
64 kfree(b->h.items);
65 kfree(b);
66}
67
68void crush_destroy_bucket_list(struct crush_bucket_list *b)
69{
70 kfree(b->item_weights);
71 kfree(b->sum_weights);
72 kfree(b->h.perm);
73 kfree(b->h.items);
74 kfree(b);
75}
76
77void crush_destroy_bucket_tree(struct crush_bucket_tree *b)
78{
79 kfree(b->node_weights);
80 kfree(b);
81}
82
83void crush_destroy_bucket_straw(struct crush_bucket_straw *b)
84{
85 kfree(b->straws);
86 kfree(b->item_weights);
87 kfree(b->h.perm);
88 kfree(b->h.items);
89 kfree(b);
90}
91
92void crush_destroy_bucket(struct crush_bucket *b)
93{
94 switch (b->alg) {
95 case CRUSH_BUCKET_UNIFORM:
96 crush_destroy_bucket_uniform((struct crush_bucket_uniform *)b);
97 break;
98 case CRUSH_BUCKET_LIST:
99 crush_destroy_bucket_list((struct crush_bucket_list *)b);
100 break;
101 case CRUSH_BUCKET_TREE:
102 crush_destroy_bucket_tree((struct crush_bucket_tree *)b);
103 break;
104 case CRUSH_BUCKET_STRAW:
105 crush_destroy_bucket_straw((struct crush_bucket_straw *)b);
106 break;
107 }
108}
109
110/**
111 * crush_destroy - Destroy a crush_map
112 * @map: crush_map pointer
113 */
114void crush_destroy(struct crush_map *map)
115{
116 int b;
117
118 /* buckets */
119 if (map->buckets) {
120 for (b = 0; b < map->max_buckets; b++) {
121 if (map->buckets[b] == NULL)
122 continue;
123 crush_destroy_bucket(map->buckets[b]);
124 }
125 kfree(map->buckets);
126 }
127
128 /* rules */
129 if (map->rules) {
130 for (b = 0; b < map->max_rules; b++)
131 kfree(map->rules[b]);
132 kfree(map->rules);
133 }
134
135 kfree(map->bucket_parents);
136 kfree(map->device_parents);
137 kfree(map);
138}
139
140
diff --git a/fs/ceph/crush/crush.h b/fs/ceph/crush/crush.h
new file mode 100644
index 000000000000..9ac7e091126f
--- /dev/null
+++ b/fs/ceph/crush/crush.h
@@ -0,0 +1,188 @@
1#ifndef _CRUSH_CRUSH_H
2#define _CRUSH_CRUSH_H
3
4#include <linux/types.h>
5
6/*
7 * CRUSH is a pseudo-random data distribution algorithm that
8 * efficiently distributes input values (typically, data objects)
9 * across a heterogeneous, structured storage cluster.
10 *
11 * The algorithm was originally described in detail in this paper
12 * (although the algorithm has evolved somewhat since then):
13 *
14 * http://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf
15 *
16 * LGPL2
17 */
18
19
20#define CRUSH_MAGIC 0x00010000ul /* for detecting algorithm revisions */
21
22
23#define CRUSH_MAX_DEPTH 10 /* max crush hierarchy depth */
24#define CRUSH_MAX_SET 10 /* max size of a mapping result */
25
26
27/*
28 * CRUSH uses user-defined "rules" to describe how inputs should be
29 * mapped to devices. A rule consists of sequence of steps to perform
30 * to generate the set of output devices.
31 */
32struct crush_rule_step {
33 __u32 op;
34 __s32 arg1;
35 __s32 arg2;
36};
37
38/* step op codes */
39enum {
40 CRUSH_RULE_NOOP = 0,
41 CRUSH_RULE_TAKE = 1, /* arg1 = value to start with */
42 CRUSH_RULE_CHOOSE_FIRSTN = 2, /* arg1 = num items to pick */
43 /* arg2 = type */
44 CRUSH_RULE_CHOOSE_INDEP = 3, /* same */
45 CRUSH_RULE_EMIT = 4, /* no args */
46 CRUSH_RULE_CHOOSE_LEAF_FIRSTN = 6,
47 CRUSH_RULE_CHOOSE_LEAF_INDEP = 7,
48};
49
50/*
51 * for specifying choose num (arg1) relative to the max parameter
52 * passed to do_rule
53 */
54#define CRUSH_CHOOSE_N 0
55#define CRUSH_CHOOSE_N_MINUS(x) (-(x))
56
57/*
58 * The rule mask is used to describe what the rule is intended for.
59 * Given a ruleset and size of output set, we search through the
60 * rule list for a matching rule_mask.
61 */
62struct crush_rule_mask {
63 __u8 ruleset;
64 __u8 type;
65 __u8 min_size;
66 __u8 max_size;
67};
68
69struct crush_rule {
70 __u32 len;
71 struct crush_rule_mask mask;
72 struct crush_rule_step steps[0];
73};
74
75#define crush_rule_size(len) (sizeof(struct crush_rule) + \
76 (len)*sizeof(struct crush_rule_step))
77
78
79
80/*
81 * A bucket is a named container of other items (either devices or
82 * other buckets). Items within a bucket are chosen using one of a
83 * few different algorithms. The table summarizes how the speed of
84 * each option measures up against mapping stability when items are
85 * added or removed.
86 *
87 * Bucket Alg Speed Additions Removals
88 * ------------------------------------------------
89 * uniform O(1) poor poor
90 * list O(n) optimal poor
91 * tree O(log n) good good
92 * straw O(n) optimal optimal
93 */
94enum {
95 CRUSH_BUCKET_UNIFORM = 1,
96 CRUSH_BUCKET_LIST = 2,
97 CRUSH_BUCKET_TREE = 3,
98 CRUSH_BUCKET_STRAW = 4
99};
100static inline const char *crush_bucket_alg_name(int alg)
101{
102 switch (alg) {
103 case CRUSH_BUCKET_UNIFORM: return "uniform";
104 case CRUSH_BUCKET_LIST: return "list";
105 case CRUSH_BUCKET_TREE: return "tree";
106 case CRUSH_BUCKET_STRAW: return "straw";
107 default: return "unknown";
108 }
109}
110
111struct crush_bucket {
112 __s32 id; /* this'll be negative */
113 __u16 type; /* non-zero; type=0 is reserved for devices */
114 __u16 alg; /* one of CRUSH_BUCKET_* */
115 __u32 weight; /* 16-bit fixed point */
116 __u32 size; /* num items */
117 __s32 *items;
118
119 /*
120 * cached random permutation: used for uniform bucket and for
121 * the linear search fallback for the other bucket types.
122 */
123 __u32 perm_x; /* @x for which *perm is defined */
124 __u32 perm_n; /* num elements of *perm that are permuted/defined */
125 __u32 *perm;
126};
127
128struct crush_bucket_uniform {
129 struct crush_bucket h;
130 __u32 item_weight; /* 16-bit fixed point; all items equally weighted */
131};
132
133struct crush_bucket_list {
134 struct crush_bucket h;
135 __u32 *item_weights; /* 16-bit fixed point */
136 __u32 *sum_weights; /* 16-bit fixed point. element i is sum
137 of weights 0..i, inclusive */
138};
139
140struct crush_bucket_tree {
141 struct crush_bucket h; /* note: h.size is _tree_ size, not number of
142 actual items */
143 __u8 num_nodes;
144 __u32 *node_weights;
145};
146
147struct crush_bucket_straw {
148 struct crush_bucket h;
149 __u32 *item_weights; /* 16-bit fixed point */
150 __u32 *straws; /* 16-bit fixed point */
151};
152
153
154
155/*
156 * CRUSH map includes all buckets, rules, etc.
157 */
158struct crush_map {
159 struct crush_bucket **buckets;
160 struct crush_rule **rules;
161
162 /*
163 * Parent pointers to identify the parent bucket a device or
164 * bucket in the hierarchy. If an item appears more than
165 * once, this is the _last_ time it appeared (where buckets
166 * are processed in bucket id order, from -1 on down to
167 * -max_buckets.
168 */
169 __u32 *bucket_parents;
170 __u32 *device_parents;
171
172 __s32 max_buckets;
173 __u32 max_rules;
174 __s32 max_devices;
175};
176
177
178/* crush.c */
179extern int crush_get_bucket_item_weight(struct crush_bucket *b, int pos);
180extern void crush_calc_parents(struct crush_map *map);
181extern void crush_destroy_bucket_uniform(struct crush_bucket_uniform *b);
182extern void crush_destroy_bucket_list(struct crush_bucket_list *b);
183extern void crush_destroy_bucket_tree(struct crush_bucket_tree *b);
184extern void crush_destroy_bucket_straw(struct crush_bucket_straw *b);
185extern void crush_destroy_bucket(struct crush_bucket *b);
186extern void crush_destroy(struct crush_map *map);
187
188#endif
diff --git a/fs/ceph/crush/hash.h b/fs/ceph/crush/hash.h
new file mode 100644
index 000000000000..42f3312783a1
--- /dev/null
+++ b/fs/ceph/crush/hash.h
@@ -0,0 +1,90 @@
1#ifndef _CRUSH_HASH_H
2#define _CRUSH_HASH_H
3
4/*
5 * Robert Jenkins' function for mixing 32-bit values
6 * http://burtleburtle.net/bob/hash/evahash.html
7 * a, b = random bits, c = input and output
8 */
9#define crush_hashmix(a, b, c) do { \
10 a = a-b; a = a-c; a = a^(c>>13); \
11 b = b-c; b = b-a; b = b^(a<<8); \
12 c = c-a; c = c-b; c = c^(b>>13); \
13 a = a-b; a = a-c; a = a^(c>>12); \
14 b = b-c; b = b-a; b = b^(a<<16); \
15 c = c-a; c = c-b; c = c^(b>>5); \
16 a = a-b; a = a-c; a = a^(c>>3); \
17 b = b-c; b = b-a; b = b^(a<<10); \
18 c = c-a; c = c-b; c = c^(b>>15); \
19 } while (0)
20
21#define crush_hash_seed 1315423911
22
23static inline __u32 crush_hash32(__u32 a)
24{
25 __u32 hash = crush_hash_seed ^ a;
26 __u32 b = a;
27 __u32 x = 231232;
28 __u32 y = 1232;
29 crush_hashmix(b, x, hash);
30 crush_hashmix(y, a, hash);
31 return hash;
32}
33
34static inline __u32 crush_hash32_2(__u32 a, __u32 b)
35{
36 __u32 hash = crush_hash_seed ^ a ^ b;
37 __u32 x = 231232;
38 __u32 y = 1232;
39 crush_hashmix(a, b, hash);
40 crush_hashmix(x, a, hash);
41 crush_hashmix(b, y, hash);
42 return hash;
43}
44
45static inline __u32 crush_hash32_3(__u32 a, __u32 b, __u32 c)
46{
47 __u32 hash = crush_hash_seed ^ a ^ b ^ c;
48 __u32 x = 231232;
49 __u32 y = 1232;
50 crush_hashmix(a, b, hash);
51 crush_hashmix(c, x, hash);
52 crush_hashmix(y, a, hash);
53 crush_hashmix(b, x, hash);
54 crush_hashmix(y, c, hash);
55 return hash;
56}
57
58static inline __u32 crush_hash32_4(__u32 a, __u32 b, __u32 c,
59 __u32 d)
60{
61 __u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d;
62 __u32 x = 231232;
63 __u32 y = 1232;
64 crush_hashmix(a, b, hash);
65 crush_hashmix(c, d, hash);
66 crush_hashmix(a, x, hash);
67 crush_hashmix(y, b, hash);
68 crush_hashmix(c, x, hash);
69 crush_hashmix(y, d, hash);
70 return hash;
71}
72
73static inline __u32 crush_hash32_5(__u32 a, __u32 b, __u32 c,
74 __u32 d, __u32 e)
75{
76 __u32 hash = crush_hash_seed ^ a ^ b ^ c ^ d ^ e;
77 __u32 x = 231232;
78 __u32 y = 1232;
79 crush_hashmix(a, b, hash);
80 crush_hashmix(c, d, hash);
81 crush_hashmix(e, x, hash);
82 crush_hashmix(y, a, hash);
83 crush_hashmix(b, x, hash);
84 crush_hashmix(y, c, hash);
85 crush_hashmix(d, x, hash);
86 crush_hashmix(y, e, hash);
87 return hash;
88}
89
90#endif
diff --git a/fs/ceph/crush/mapper.c b/fs/ceph/crush/mapper.c
new file mode 100644
index 000000000000..0f0730c62695
--- /dev/null
+++ b/fs/ceph/crush/mapper.c
@@ -0,0 +1,589 @@
1
2#ifdef __KERNEL__
3# include <linux/string.h>
4# include <linux/slab.h>
5# include <linux/bug.h>
6# include <linux/kernel.h>
7# ifndef dprintk
8# define dprintk(args...)
9# endif
10#else
11# include <string.h>
12# include <stdio.h>
13# include <stdlib.h>
14# include <assert.h>
15# define BUG_ON(x) assert(!(x))
16# define dprintk(args...) /* printf(args) */
17# define kmalloc(x, f) malloc(x)
18# define kfree(x) free(x)
19#endif
20
21#include "crush.h"
22#include "hash.h"
23
24/*
25 * Implement the core CRUSH mapping algorithm.
26 */
27
28/**
29 * crush_find_rule - find a crush_rule id for a given ruleset, type, and size.
30 * @map: the crush_map
31 * @ruleset: the storage ruleset id (user defined)
32 * @type: storage ruleset type (user defined)
33 * @size: output set size
34 */
35int crush_find_rule(struct crush_map *map, int ruleset, int type, int size)
36{
37 int i;
38
39 for (i = 0; i < map->max_rules; i++) {
40 if (map->rules[i] &&
41 map->rules[i]->mask.ruleset == ruleset &&
42 map->rules[i]->mask.type == type &&
43 map->rules[i]->mask.min_size <= size &&
44 map->rules[i]->mask.max_size >= size)
45 return i;
46 }
47 return -1;
48}
49
50
51/*
52 * bucket choose methods
53 *
54 * For each bucket algorithm, we have a "choose" method that, given a
55 * crush input @x and replica position (usually, position in output set) @r,
56 * will produce an item in the bucket.
57 */
58
59/*
60 * Choose based on a random permutation of the bucket.
61 *
62 * We used to use some prime number arithmetic to do this, but it
63 * wasn't very random, and had some other bad behaviors. Instead, we
64 * calculate an actual random permutation of the bucket members.
65 * Since this is expensive, we optimize for the r=0 case, which
66 * captures the vast majority of calls.
67 */
68static int bucket_perm_choose(struct crush_bucket *bucket,
69 int x, int r)
70{
71 unsigned pr = r % bucket->size;
72 unsigned i, s;
73
74 /* start a new permutation if @x has changed */
75 if (bucket->perm_x != x || bucket->perm_n == 0) {
76 dprintk("bucket %d new x=%d\n", bucket->id, x);
77 bucket->perm_x = x;
78
79 /* optimize common r=0 case */
80 if (pr == 0) {
81 s = crush_hash32_3(x, bucket->id, 0) %
82 bucket->size;
83 bucket->perm[0] = s;
84 bucket->perm_n = 0xffff; /* magic value, see below */
85 goto out;
86 }
87
88 for (i = 0; i < bucket->size; i++)
89 bucket->perm[i] = i;
90 bucket->perm_n = 0;
91 } else if (bucket->perm_n == 0xffff) {
92 /* clean up after the r=0 case above */
93 for (i = 1; i < bucket->size; i++)
94 bucket->perm[i] = i;
95 bucket->perm[bucket->perm[0]] = 0;
96 bucket->perm_n = 1;
97 }
98
99 /* calculate permutation up to pr */
100 for (i = 0; i < bucket->perm_n; i++)
101 dprintk(" perm_choose have %d: %d\n", i, bucket->perm[i]);
102 while (bucket->perm_n <= pr) {
103 unsigned p = bucket->perm_n;
104 /* no point in swapping the final entry */
105 if (p < bucket->size - 1) {
106 i = crush_hash32_3(x, bucket->id, p) %
107 (bucket->size - p);
108 if (i) {
109 unsigned t = bucket->perm[p + i];
110 bucket->perm[p + i] = bucket->perm[p];
111 bucket->perm[p] = t;
112 }
113 dprintk(" perm_choose swap %d with %d\n", p, p+i);
114 }
115 bucket->perm_n++;
116 }
117 for (i = 0; i < bucket->size; i++)
118 dprintk(" perm_choose %d: %d\n", i, bucket->perm[i]);
119
120 s = bucket->perm[pr];
121out:
122 dprintk(" perm_choose %d sz=%d x=%d r=%d (%d) s=%d\n", bucket->id,
123 bucket->size, x, r, pr, s);
124 return bucket->items[s];
125}
126
127/* uniform */
128static int bucket_uniform_choose(struct crush_bucket_uniform *bucket,
129 int x, int r)
130{
131 return bucket_perm_choose(&bucket->h, x, r);
132}
133
134/* list */
135static int bucket_list_choose(struct crush_bucket_list *bucket,
136 int x, int r)
137{
138 int i;
139
140 for (i = bucket->h.size-1; i >= 0; i--) {
141 __u64 w = crush_hash32_4(x, bucket->h.items[i], r,
142 bucket->h.id);
143 w &= 0xffff;
144 dprintk("list_choose i=%d x=%d r=%d item %d weight %x "
145 "sw %x rand %llx",
146 i, x, r, bucket->h.items[i], bucket->item_weights[i],
147 bucket->sum_weights[i], w);
148 w *= bucket->sum_weights[i];
149 w = w >> 16;
150 /*dprintk(" scaled %llx\n", w);*/
151 if (w < bucket->item_weights[i])
152 return bucket->h.items[i];
153 }
154
155 BUG_ON(1);
156 return 0;
157}
158
159
160/* (binary) tree */
161static int height(int n)
162{
163 int h = 0;
164 while ((n & 1) == 0) {
165 h++;
166 n = n >> 1;
167 }
168 return h;
169}
170
171static int left(int x)
172{
173 int h = height(x);
174 return x - (1 << (h-1));
175}
176
177static int right(int x)
178{
179 int h = height(x);
180 return x + (1 << (h-1));
181}
182
183static int terminal(int x)
184{
185 return x & 1;
186}
187
188static int bucket_tree_choose(struct crush_bucket_tree *bucket,
189 int x, int r)
190{
191 int n, l;
192 __u32 w;
193 __u64 t;
194
195 /* start at root */
196 n = bucket->num_nodes >> 1;
197
198 while (!terminal(n)) {
199 /* pick point in [0, w) */
200 w = bucket->node_weights[n];
201 t = (__u64)crush_hash32_4(x, n, r, bucket->h.id) * (__u64)w;
202 t = t >> 32;
203
204 /* descend to the left or right? */
205 l = left(n);
206 if (t < bucket->node_weights[l])
207 n = l;
208 else
209 n = right(n);
210 }
211
212 return bucket->h.items[n >> 1];
213}
214
215
216/* straw */
217
218static int bucket_straw_choose(struct crush_bucket_straw *bucket,
219 int x, int r)
220{
221 int i;
222 int high = 0;
223 __u64 high_draw = 0;
224 __u64 draw;
225
226 for (i = 0; i < bucket->h.size; i++) {
227 draw = crush_hash32_3(x, bucket->h.items[i], r);
228 draw &= 0xffff;
229 draw *= bucket->straws[i];
230 if (i == 0 || draw > high_draw) {
231 high = i;
232 high_draw = draw;
233 }
234 }
235 return bucket->h.items[high];
236}
237
238static int crush_bucket_choose(struct crush_bucket *in, int x, int r)
239{
240 dprintk("choose %d x=%d r=%d\n", in->id, x, r);
241 switch (in->alg) {
242 case CRUSH_BUCKET_UNIFORM:
243 return bucket_uniform_choose((struct crush_bucket_uniform *)in,
244 x, r);
245 case CRUSH_BUCKET_LIST:
246 return bucket_list_choose((struct crush_bucket_list *)in,
247 x, r);
248 case CRUSH_BUCKET_TREE:
249 return bucket_tree_choose((struct crush_bucket_tree *)in,
250 x, r);
251 case CRUSH_BUCKET_STRAW:
252 return bucket_straw_choose((struct crush_bucket_straw *)in,
253 x, r);
254 default:
255 BUG_ON(1);
256/* return in->items[0] */;
257 }
258}
259
260/*
261 * true if device is marked "out" (failed, fully offloaded)
262 * of the cluster
263 */
264static int is_out(struct crush_map *map, __u32 *weight, int item, int x)
265{
266 if (weight[item] >= 0x1000)
267 return 0;
268 if (weight[item] == 0)
269 return 1;
270 if ((crush_hash32_2(x, item) & 0xffff) < weight[item])
271 return 0;
272 return 1;
273}
274
275/**
276 * crush_choose - choose numrep distinct items of given type
277 * @map: the crush_map
278 * @bucket: the bucket we are choose an item from
279 * @x: crush input value
280 * @numrep: the number of items to choose
281 * @type: the type of item to choose
282 * @out: pointer to output vector
283 * @outpos: our position in that vector
284 * @firstn: true if choosing "first n" items, false if choosing "indep"
285 * @recurse_to_leaf: true if we want one device under each item of given type
286 * @out2: second output vector for leaf items (if @recurse_to_leaf)
287 */
288static int crush_choose(struct crush_map *map,
289 struct crush_bucket *bucket,
290 __u32 *weight,
291 int x, int numrep, int type,
292 int *out, int outpos,
293 int firstn, int recurse_to_leaf,
294 int *out2)
295{
296 int rep;
297 int ftotal, flocal;
298 int retry_descent, retry_bucket, skip_rep;
299 struct crush_bucket *in = bucket;
300 int r;
301 int i;
302 int item;
303 int itemtype;
304 int collide, reject;
305 const int orig_tries = 5; /* attempts before we fall back to search */
306 dprintk("choose bucket %d x %d outpos %d\n", bucket->id, x, outpos);
307
308 for (rep = outpos; rep < numrep; rep++) {
309 /* keep trying until we get a non-out, non-colliding item */
310 ftotal = 0;
311 skip_rep = 0;
312 do {
313 retry_descent = 0;
314 in = bucket; /* initial bucket */
315
316 /* choose through intervening buckets */
317 flocal = 0;
318 do {
319 retry_bucket = 0;
320 r = rep;
321 if (in->alg == CRUSH_BUCKET_UNIFORM) {
322 /* be careful */
323 if (firstn || numrep >= in->size)
324 /* r' = r + f_total */
325 r += ftotal;
326 else if (in->size % numrep == 0)
327 /* r'=r+(n+1)*f_local */
328 r += (numrep+1) *
329 (flocal+ftotal);
330 else
331 /* r' = r + n*f_local */
332 r += numrep * (flocal+ftotal);
333 } else {
334 if (firstn)
335 /* r' = r + f_total */
336 r += ftotal;
337 else
338 /* r' = r + n*f_local */
339 r += numrep * (flocal+ftotal);
340 }
341
342 /* bucket choose */
343 if (flocal >= (in->size>>1) &&
344 flocal > orig_tries)
345 item = bucket_perm_choose(in, x, r);
346 else
347 item = crush_bucket_choose(in, x, r);
348 BUG_ON(item >= map->max_devices);
349
350 /* desired type? */
351 if (item < 0)
352 itemtype = map->buckets[-1-item]->type;
353 else
354 itemtype = 0;
355 dprintk(" item %d type %d\n", item, itemtype);
356
357 /* keep going? */
358 if (itemtype != type) {
359 BUG_ON(item >= 0 ||
360 (-1-item) >= map->max_buckets);
361 in = map->buckets[-1-item];
362 continue;
363 }
364
365 /* collision? */
366 collide = 0;
367 for (i = 0; i < outpos; i++) {
368 if (out[i] == item) {
369 collide = 1;
370 break;
371 }
372 }
373
374 if (recurse_to_leaf &&
375 item < 0 &&
376 crush_choose(map, map->buckets[-1-item],
377 weight,
378 x, outpos+1, 0,
379 out2, outpos,
380 firstn, 0, NULL) <= outpos) {
381 reject = 1;
382 } else {
383 /* out? */
384 if (itemtype == 0)
385 reject = is_out(map, weight,
386 item, x);
387 else
388 reject = 0;
389 }
390
391 if (reject || collide) {
392 ftotal++;
393 flocal++;
394
395 if (collide && flocal < 3)
396 /* retry locally a few times */
397 retry_bucket = 1;
398 else if (flocal < in->size + orig_tries)
399 /* exhaustive bucket search */
400 retry_bucket = 1;
401 else if (ftotal < 20)
402 /* then retry descent */
403 retry_descent = 1;
404 else
405 /* else give up */
406 skip_rep = 1;
407 dprintk(" reject %d collide %d "
408 "ftotal %d flocal %d\n",
409 reject, collide, ftotal,
410 flocal);
411 }
412 } while (retry_bucket);
413 } while (retry_descent);
414
415 if (skip_rep) {
416 dprintk("skip rep\n");
417 continue;
418 }
419
420 dprintk("choose got %d\n", item);
421 out[outpos] = item;
422 outpos++;
423 }
424
425 dprintk("choose returns %d\n", outpos);
426 return outpos;
427}
428
429
430/**
431 * crush_do_rule - calculate a mapping with the given input and rule
432 * @map: the crush_map
433 * @ruleno: the rule id
434 * @x: hash input
435 * @result: pointer to result vector
436 * @result_max: maximum result size
437 * @force: force initial replica choice; -1 for none
438 */
439int crush_do_rule(struct crush_map *map,
440 int ruleno, int x, int *result, int result_max,
441 int force, __u32 *weight)
442{
443 int result_len;
444 int force_context[CRUSH_MAX_DEPTH];
445 int force_pos = -1;
446 int a[CRUSH_MAX_SET];
447 int b[CRUSH_MAX_SET];
448 int c[CRUSH_MAX_SET];
449 int recurse_to_leaf;
450 int *w;
451 int wsize = 0;
452 int *o;
453 int osize;
454 int *tmp;
455 struct crush_rule *rule;
456 int step;
457 int i, j;
458 int numrep;
459 int firstn;
460 int rc = -1;
461
462 BUG_ON(ruleno >= map->max_rules);
463
464 rule = map->rules[ruleno];
465 result_len = 0;
466 w = a;
467 o = b;
468
469 /*
470 * determine hierarchical context of force, if any. note
471 * that this may or may not correspond to the specific types
472 * referenced by the crush rule.
473 */
474 if (force >= 0) {
475 if (force >= map->max_devices ||
476 map->device_parents[force] == 0) {
477 /*dprintk("CRUSH: forcefed device dne\n");*/
478 rc = -1; /* force fed device dne */
479 goto out;
480 }
481 if (!is_out(map, weight, force, x)) {
482 while (1) {
483 force_context[++force_pos] = force;
484 if (force >= 0)
485 force = map->device_parents[force];
486 else
487 force = map->bucket_parents[-1-force];
488 if (force == 0)
489 break;
490 }
491 }
492 }
493
494 for (step = 0; step < rule->len; step++) {
495 firstn = 0;
496 switch (rule->steps[step].op) {
497 case CRUSH_RULE_TAKE:
498 w[0] = rule->steps[step].arg1;
499 if (force_pos >= 0) {
500 BUG_ON(force_context[force_pos] != w[0]);
501 force_pos--;
502 }
503 wsize = 1;
504 break;
505
506 case CRUSH_RULE_CHOOSE_LEAF_FIRSTN:
507 case CRUSH_RULE_CHOOSE_FIRSTN:
508 firstn = 1;
509 case CRUSH_RULE_CHOOSE_LEAF_INDEP:
510 case CRUSH_RULE_CHOOSE_INDEP:
511 BUG_ON(wsize == 0);
512
513 recurse_to_leaf =
514 rule->steps[step].op ==
515 CRUSH_RULE_CHOOSE_LEAF_FIRSTN ||
516 rule->steps[step].op ==
517 CRUSH_RULE_CHOOSE_LEAF_INDEP;
518
519 /* reset output */
520 osize = 0;
521
522 for (i = 0; i < wsize; i++) {
523 /*
524 * see CRUSH_N, CRUSH_N_MINUS macros.
525 * basically, numrep <= 0 means relative to
526 * the provided result_max
527 */
528 numrep = rule->steps[step].arg1;
529 if (numrep <= 0) {
530 numrep += result_max;
531 if (numrep <= 0)
532 continue;
533 }
534 j = 0;
535 if (osize == 0 && force_pos >= 0) {
536 /* skip any intermediate types */
537 while (force_pos &&
538 force_context[force_pos] < 0 &&
539 rule->steps[step].arg2 !=
540 map->buckets[-1 -
541 force_context[force_pos]]->type)
542 force_pos--;
543 o[osize] = force_context[force_pos];
544 if (recurse_to_leaf)
545 c[osize] = force_context[0];
546 j++;
547 force_pos--;
548 }
549 osize += crush_choose(map,
550 map->buckets[-1-w[i]],
551 weight,
552 x, numrep,
553 rule->steps[step].arg2,
554 o+osize, j,
555 firstn,
556 recurse_to_leaf, c+osize);
557 }
558
559 if (recurse_to_leaf)
560 /* copy final _leaf_ values to output set */
561 memcpy(o, c, osize*sizeof(*o));
562
563 /* swap t and w arrays */
564 tmp = o;
565 o = w;
566 w = tmp;
567 wsize = osize;
568 break;
569
570
571 case CRUSH_RULE_EMIT:
572 for (i = 0; i < wsize && result_len < result_max; i++) {
573 result[result_len] = w[i];
574 result_len++;
575 }
576 wsize = 0;
577 break;
578
579 default:
580 BUG_ON(1);
581 }
582 }
583 rc = result_len;
584
585out:
586 return rc;
587}
588
589
diff --git a/fs/ceph/crush/mapper.h b/fs/ceph/crush/mapper.h
new file mode 100644
index 000000000000..98e90046fd9f
--- /dev/null
+++ b/fs/ceph/crush/mapper.h
@@ -0,0 +1,20 @@
1#ifndef _CRUSH_MAPPER_H
2#define _CRUSH_MAPPER_H
3
4/*
5 * CRUSH functions for find rules and then mapping an input to an
6 * output set.
7 *
8 * LGPL2
9 */
10
11#include "crush.h"
12
13extern int crush_find_rule(struct crush_map *map, int pool, int type, int size);
14extern int crush_do_rule(struct crush_map *map,
15 int ruleno,
16 int x, int *result, int result_max,
17 int forcefeed, /* -1 for none */
18 __u32 *weights);
19
20#endif
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-21 10:45:59 -0500