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Commit | Line | Data |
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b459be73 ID |
1 | /* |
2 | * Ceph - scalable distributed file system | |
3 | * | |
4 | * Copyright (C) 2015 Intel Corporation All Rights Reserved | |
5 | * | |
6 | * This is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License version 2.1, as published by the Free Software | |
9 | * Foundation. See file COPYING. | |
10 | * | |
11 | */ | |
5ecc0a0f SW |
12 | |
13 | #ifdef __KERNEL__ | |
14 | # include <linux/string.h> | |
15 | # include <linux/slab.h> | |
16 | # include <linux/bug.h> | |
17 | # include <linux/kernel.h> | |
b459be73 ID |
18 | # include <linux/crush/crush.h> |
19 | # include <linux/crush/hash.h> | |
5ecc0a0f | 20 | #else |
b459be73 ID |
21 | # include "crush_compat.h" |
22 | # include "crush.h" | |
23 | # include "hash.h" | |
5ecc0a0f | 24 | #endif |
958a2765 | 25 | #include "crush_ln_table.h" |
5ecc0a0f | 26 | |
b459be73 ID |
27 | #define dprintk(args...) /* printf(args) */ |
28 | ||
5ecc0a0f SW |
29 | /* |
30 | * Implement the core CRUSH mapping algorithm. | |
31 | */ | |
32 | ||
33 | /** | |
34 | * crush_find_rule - find a crush_rule id for a given ruleset, type, and size. | |
35 | * @map: the crush_map | |
36 | * @ruleset: the storage ruleset id (user defined) | |
37 | * @type: storage ruleset type (user defined) | |
38 | * @size: output set size | |
39 | */ | |
8b12d47b | 40 | int crush_find_rule(const struct crush_map *map, int ruleset, int type, int size) |
5ecc0a0f | 41 | { |
8b12d47b | 42 | __u32 i; |
5ecc0a0f SW |
43 | |
44 | for (i = 0; i < map->max_rules; i++) { | |
45 | if (map->rules[i] && | |
46 | map->rules[i]->mask.ruleset == ruleset && | |
47 | map->rules[i]->mask.type == type && | |
48 | map->rules[i]->mask.min_size <= size && | |
49 | map->rules[i]->mask.max_size >= size) | |
50 | return i; | |
51 | } | |
52 | return -1; | |
53 | } | |
54 | ||
55 | ||
56 | /* | |
57 | * bucket choose methods | |
58 | * | |
59 | * For each bucket algorithm, we have a "choose" method that, given a | |
60 | * crush input @x and replica position (usually, position in output set) @r, | |
61 | * will produce an item in the bucket. | |
62 | */ | |
63 | ||
64 | /* | |
65 | * Choose based on a random permutation of the bucket. | |
66 | * | |
67 | * We used to use some prime number arithmetic to do this, but it | |
68 | * wasn't very random, and had some other bad behaviors. Instead, we | |
69 | * calculate an actual random permutation of the bucket members. | |
70 | * Since this is expensive, we optimize for the r=0 case, which | |
71 | * captures the vast majority of calls. | |
72 | */ | |
73 | static int bucket_perm_choose(struct crush_bucket *bucket, | |
74 | int x, int r) | |
75 | { | |
95c96174 ED |
76 | unsigned int pr = r % bucket->size; |
77 | unsigned int i, s; | |
5ecc0a0f SW |
78 | |
79 | /* start a new permutation if @x has changed */ | |
8b12d47b | 80 | if (bucket->perm_x != (__u32)x || bucket->perm_n == 0) { |
5ecc0a0f SW |
81 | dprintk("bucket %d new x=%d\n", bucket->id, x); |
82 | bucket->perm_x = x; | |
83 | ||
84 | /* optimize common r=0 case */ | |
85 | if (pr == 0) { | |
fb690390 | 86 | s = crush_hash32_3(bucket->hash, x, bucket->id, 0) % |
5ecc0a0f SW |
87 | bucket->size; |
88 | bucket->perm[0] = s; | |
89 | bucket->perm_n = 0xffff; /* magic value, see below */ | |
90 | goto out; | |
91 | } | |
92 | ||
93 | for (i = 0; i < bucket->size; i++) | |
94 | bucket->perm[i] = i; | |
95 | bucket->perm_n = 0; | |
96 | } else if (bucket->perm_n == 0xffff) { | |
97 | /* clean up after the r=0 case above */ | |
98 | for (i = 1; i < bucket->size; i++) | |
99 | bucket->perm[i] = i; | |
100 | bucket->perm[bucket->perm[0]] = 0; | |
101 | bucket->perm_n = 1; | |
102 | } | |
103 | ||
104 | /* calculate permutation up to pr */ | |
105 | for (i = 0; i < bucket->perm_n; i++) | |
106 | dprintk(" perm_choose have %d: %d\n", i, bucket->perm[i]); | |
107 | while (bucket->perm_n <= pr) { | |
95c96174 | 108 | unsigned int p = bucket->perm_n; |
5ecc0a0f SW |
109 | /* no point in swapping the final entry */ |
110 | if (p < bucket->size - 1) { | |
fb690390 | 111 | i = crush_hash32_3(bucket->hash, x, bucket->id, p) % |
5ecc0a0f SW |
112 | (bucket->size - p); |
113 | if (i) { | |
95c96174 | 114 | unsigned int t = bucket->perm[p + i]; |
5ecc0a0f SW |
115 | bucket->perm[p + i] = bucket->perm[p]; |
116 | bucket->perm[p] = t; | |
117 | } | |
118 | dprintk(" perm_choose swap %d with %d\n", p, p+i); | |
119 | } | |
120 | bucket->perm_n++; | |
121 | } | |
122 | for (i = 0; i < bucket->size; i++) | |
123 | dprintk(" perm_choose %d: %d\n", i, bucket->perm[i]); | |
124 | ||
125 | s = bucket->perm[pr]; | |
126 | out: | |
127 | dprintk(" perm_choose %d sz=%d x=%d r=%d (%d) s=%d\n", bucket->id, | |
128 | bucket->size, x, r, pr, s); | |
129 | return bucket->items[s]; | |
130 | } | |
131 | ||
132 | /* uniform */ | |
133 | static int bucket_uniform_choose(struct crush_bucket_uniform *bucket, | |
134 | int x, int r) | |
135 | { | |
136 | return bucket_perm_choose(&bucket->h, x, r); | |
137 | } | |
138 | ||
139 | /* list */ | |
140 | static int bucket_list_choose(struct crush_bucket_list *bucket, | |
141 | int x, int r) | |
142 | { | |
143 | int i; | |
144 | ||
145 | for (i = bucket->h.size-1; i >= 0; i--) { | |
b459be73 | 146 | __u64 w = crush_hash32_4(bucket->h.hash, x, bucket->h.items[i], |
fb690390 | 147 | r, bucket->h.id); |
5ecc0a0f SW |
148 | w &= 0xffff; |
149 | dprintk("list_choose i=%d x=%d r=%d item %d weight %x " | |
150 | "sw %x rand %llx", | |
151 | i, x, r, bucket->h.items[i], bucket->item_weights[i], | |
152 | bucket->sum_weights[i], w); | |
153 | w *= bucket->sum_weights[i]; | |
154 | w = w >> 16; | |
155 | /*dprintk(" scaled %llx\n", w);*/ | |
156 | if (w < bucket->item_weights[i]) | |
157 | return bucket->h.items[i]; | |
158 | } | |
159 | ||
a1f4895b SW |
160 | dprintk("bad list sums for bucket %d\n", bucket->h.id); |
161 | return bucket->h.items[0]; | |
5ecc0a0f SW |
162 | } |
163 | ||
164 | ||
165 | /* (binary) tree */ | |
166 | static int height(int n) | |
167 | { | |
168 | int h = 0; | |
169 | while ((n & 1) == 0) { | |
170 | h++; | |
171 | n = n >> 1; | |
172 | } | |
173 | return h; | |
174 | } | |
175 | ||
176 | static int left(int x) | |
177 | { | |
178 | int h = height(x); | |
179 | return x - (1 << (h-1)); | |
180 | } | |
181 | ||
182 | static int right(int x) | |
183 | { | |
184 | int h = height(x); | |
185 | return x + (1 << (h-1)); | |
186 | } | |
187 | ||
188 | static int terminal(int x) | |
189 | { | |
190 | return x & 1; | |
191 | } | |
192 | ||
193 | static int bucket_tree_choose(struct crush_bucket_tree *bucket, | |
194 | int x, int r) | |
195 | { | |
8f99c85b | 196 | int n; |
5ecc0a0f SW |
197 | __u32 w; |
198 | __u64 t; | |
199 | ||
200 | /* start at root */ | |
201 | n = bucket->num_nodes >> 1; | |
202 | ||
203 | while (!terminal(n)) { | |
8f99c85b | 204 | int l; |
5ecc0a0f SW |
205 | /* pick point in [0, w) */ |
206 | w = bucket->node_weights[n]; | |
fb690390 SW |
207 | t = (__u64)crush_hash32_4(bucket->h.hash, x, n, r, |
208 | bucket->h.id) * (__u64)w; | |
5ecc0a0f SW |
209 | t = t >> 32; |
210 | ||
211 | /* descend to the left or right? */ | |
212 | l = left(n); | |
213 | if (t < bucket->node_weights[l]) | |
214 | n = l; | |
215 | else | |
216 | n = right(n); | |
217 | } | |
218 | ||
219 | return bucket->h.items[n >> 1]; | |
220 | } | |
221 | ||
222 | ||
223 | /* straw */ | |
224 | ||
225 | static int bucket_straw_choose(struct crush_bucket_straw *bucket, | |
226 | int x, int r) | |
227 | { | |
8b12d47b | 228 | __u32 i; |
5ecc0a0f SW |
229 | int high = 0; |
230 | __u64 high_draw = 0; | |
231 | __u64 draw; | |
232 | ||
233 | for (i = 0; i < bucket->h.size; i++) { | |
fb690390 | 234 | draw = crush_hash32_3(bucket->h.hash, x, bucket->h.items[i], r); |
5ecc0a0f SW |
235 | draw &= 0xffff; |
236 | draw *= bucket->straws[i]; | |
237 | if (i == 0 || draw > high_draw) { | |
238 | high = i; | |
239 | high_draw = draw; | |
240 | } | |
241 | } | |
242 | return bucket->h.items[high]; | |
243 | } | |
244 | ||
b459be73 ID |
245 | /* compute 2^44*log2(input+1) */ |
246 | static __u64 crush_ln(unsigned int xin) | |
958a2765 | 247 | { |
b459be73 ID |
248 | unsigned int x = xin, x1; |
249 | int iexpon, index1, index2; | |
250 | __u64 RH, LH, LL, xl64, result; | |
958a2765 | 251 | |
b459be73 | 252 | x++; |
958a2765 | 253 | |
b459be73 ID |
254 | /* normalize input */ |
255 | iexpon = 15; | |
256 | while (!(x & 0x18000)) { | |
257 | x <<= 1; | |
258 | iexpon--; | |
259 | } | |
958a2765 | 260 | |
b459be73 ID |
261 | index1 = (x >> 8) << 1; |
262 | /* RH ~ 2^56/index1 */ | |
263 | RH = __RH_LH_tbl[index1 - 256]; | |
264 | /* LH ~ 2^48 * log2(index1/256) */ | |
265 | LH = __RH_LH_tbl[index1 + 1 - 256]; | |
958a2765 | 266 | |
b459be73 ID |
267 | /* RH*x ~ 2^48 * (2^15 + xf), xf<2^8 */ |
268 | xl64 = (__s64)x * RH; | |
269 | xl64 >>= 48; | |
270 | x1 = xl64; | |
958a2765 | 271 | |
b459be73 ID |
272 | result = iexpon; |
273 | result <<= (12 + 32); | |
958a2765 | 274 | |
b459be73 ID |
275 | index2 = x1 & 0xff; |
276 | /* LL ~ 2^48*log2(1.0+index2/2^15) */ | |
277 | LL = __LL_tbl[index2]; | |
958a2765 | 278 | |
b459be73 | 279 | LH = LH + LL; |
958a2765 | 280 | |
b459be73 ID |
281 | LH >>= (48 - 12 - 32); |
282 | result += LH; | |
958a2765 | 283 | |
b459be73 | 284 | return result; |
958a2765 ID |
285 | } |
286 | ||
287 | ||
288 | /* | |
289 | * straw2 | |
290 | * | |
291 | * for reference, see: | |
292 | * | |
293 | * http://en.wikipedia.org/wiki/Exponential_distribution#Distribution_of_the_minimum_of_exponential_random_variables | |
294 | * | |
295 | */ | |
296 | ||
297 | static int bucket_straw2_choose(struct crush_bucket_straw2 *bucket, | |
298 | int x, int r) | |
299 | { | |
b459be73 ID |
300 | unsigned int i, high = 0; |
301 | unsigned int u; | |
302 | unsigned int w; | |
958a2765 ID |
303 | __s64 ln, draw, high_draw = 0; |
304 | ||
305 | for (i = 0; i < bucket->h.size; i++) { | |
306 | w = bucket->item_weights[i]; | |
307 | if (w) { | |
308 | u = crush_hash32_3(bucket->h.hash, x, | |
309 | bucket->h.items[i], r); | |
310 | u &= 0xffff; | |
311 | ||
312 | /* | |
313 | * for some reason slightly less than 0x10000 produces | |
314 | * a slightly more accurate distribution... probably a | |
315 | * rounding effect. | |
316 | * | |
317 | * the natural log lookup table maps [0,0xffff] | |
318 | * (corresponding to real numbers [1/0x10000, 1] to | |
319 | * [0, 0xffffffffffff] (corresponding to real numbers | |
320 | * [-11.090355,0]). | |
321 | */ | |
322 | ln = crush_ln(u) - 0x1000000000000ll; | |
323 | ||
324 | /* | |
325 | * divide by 16.16 fixed-point weight. note | |
326 | * that the ln value is negative, so a larger | |
327 | * weight means a larger (less negative) value | |
328 | * for draw. | |
329 | */ | |
330 | draw = div64_s64(ln, w); | |
331 | } else { | |
332 | draw = S64_MIN; | |
333 | } | |
334 | ||
335 | if (i == 0 || draw > high_draw) { | |
336 | high = i; | |
337 | high_draw = draw; | |
338 | } | |
339 | } | |
340 | return bucket->h.items[high]; | |
341 | } | |
342 | ||
343 | ||
5ecc0a0f SW |
344 | static int crush_bucket_choose(struct crush_bucket *in, int x, int r) |
345 | { | |
a1a31e73 | 346 | dprintk(" crush_bucket_choose %d x=%d r=%d\n", in->id, x, r); |
a1f4895b | 347 | BUG_ON(in->size == 0); |
5ecc0a0f SW |
348 | switch (in->alg) { |
349 | case CRUSH_BUCKET_UNIFORM: | |
350 | return bucket_uniform_choose((struct crush_bucket_uniform *)in, | |
351 | x, r); | |
352 | case CRUSH_BUCKET_LIST: | |
353 | return bucket_list_choose((struct crush_bucket_list *)in, | |
354 | x, r); | |
355 | case CRUSH_BUCKET_TREE: | |
356 | return bucket_tree_choose((struct crush_bucket_tree *)in, | |
357 | x, r); | |
358 | case CRUSH_BUCKET_STRAW: | |
359 | return bucket_straw_choose((struct crush_bucket_straw *)in, | |
360 | x, r); | |
958a2765 ID |
361 | case CRUSH_BUCKET_STRAW2: |
362 | return bucket_straw2_choose((struct crush_bucket_straw2 *)in, | |
363 | x, r); | |
5ecc0a0f | 364 | default: |
a1f4895b | 365 | dprintk("unknown bucket %d alg %d\n", in->id, in->alg); |
50b885b9 | 366 | return in->items[0]; |
5ecc0a0f SW |
367 | } |
368 | } | |
369 | ||
958a2765 | 370 | |
5ecc0a0f SW |
371 | /* |
372 | * true if device is marked "out" (failed, fully offloaded) | |
373 | * of the cluster | |
374 | */ | |
b3b33b0e ID |
375 | static int is_out(const struct crush_map *map, |
376 | const __u32 *weight, int weight_max, | |
377 | int item, int x) | |
5ecc0a0f | 378 | { |
b3b33b0e ID |
379 | if (item >= weight_max) |
380 | return 1; | |
153a1093 | 381 | if (weight[item] >= 0x10000) |
5ecc0a0f SW |
382 | return 0; |
383 | if (weight[item] == 0) | |
384 | return 1; | |
fb690390 SW |
385 | if ((crush_hash32_2(CRUSH_HASH_RJENKINS1, x, item) & 0xffff) |
386 | < weight[item]) | |
5ecc0a0f SW |
387 | return 0; |
388 | return 1; | |
389 | } | |
390 | ||
391 | /** | |
9fe07182 | 392 | * crush_choose_firstn - choose numrep distinct items of given type |
5ecc0a0f SW |
393 | * @map: the crush_map |
394 | * @bucket: the bucket we are choose an item from | |
395 | * @x: crush input value | |
396 | * @numrep: the number of items to choose | |
397 | * @type: the type of item to choose | |
398 | * @out: pointer to output vector | |
399 | * @outpos: our position in that vector | |
45002267 | 400 | * @out_size: size of the out vector |
0e32d712 ID |
401 | * @tries: number of attempts to make |
402 | * @recurse_tries: number of attempts to have recursive chooseleaf make | |
48a163db ID |
403 | * @local_retries: localized retries |
404 | * @local_fallback_retries: localized fallback retries | |
0e32d712 | 405 | * @recurse_to_leaf: true if we want one device under each item of given type (chooseleaf instead of choose) |
dc6ae6d8 | 406 | * @stable: stable mode starts rep=0 in the recursive call for all replicas |
e2b149cc | 407 | * @vary_r: pass r to recursive calls |
5ecc0a0f | 408 | * @out2: second output vector for leaf items (if @recurse_to_leaf) |
e2b149cc | 409 | * @parent_r: r value passed from the parent |
5ecc0a0f | 410 | */ |
9fe07182 ID |
411 | static int crush_choose_firstn(const struct crush_map *map, |
412 | struct crush_bucket *bucket, | |
413 | const __u32 *weight, int weight_max, | |
414 | int x, int numrep, int type, | |
415 | int *out, int outpos, | |
45002267 | 416 | int out_size, |
2d8be0bc ID |
417 | unsigned int tries, |
418 | unsigned int recurse_tries, | |
48a163db ID |
419 | unsigned int local_retries, |
420 | unsigned int local_fallback_retries, | |
9fe07182 | 421 | int recurse_to_leaf, |
e2b149cc | 422 | unsigned int vary_r, |
dc6ae6d8 | 423 | unsigned int stable, |
e2b149cc ID |
424 | int *out2, |
425 | int parent_r) | |
5ecc0a0f SW |
426 | { |
427 | int rep; | |
8b12d47b | 428 | unsigned int ftotal, flocal; |
5ecc0a0f SW |
429 | int retry_descent, retry_bucket, skip_rep; |
430 | struct crush_bucket *in = bucket; | |
431 | int r; | |
432 | int i; | |
b28813a6 | 433 | int item = 0; |
5ecc0a0f SW |
434 | int itemtype; |
435 | int collide, reject; | |
45002267 | 436 | int count = out_size; |
a1a31e73 | 437 | |
dc6ae6d8 | 438 | dprintk("CHOOSE%s bucket %d x %d outpos %d numrep %d tries %d recurse_tries %d local_retries %d local_fallback_retries %d parent_r %d stable %d\n", |
e2b149cc ID |
439 | recurse_to_leaf ? "_LEAF" : "", |
440 | bucket->id, x, outpos, numrep, | |
441 | tries, recurse_tries, local_retries, local_fallback_retries, | |
dc6ae6d8 | 442 | parent_r, stable); |
5ecc0a0f | 443 | |
dc6ae6d8 | 444 | for (rep = stable ? 0 : outpos; rep < numrep && count > 0 ; rep++) { |
5ecc0a0f SW |
445 | /* keep trying until we get a non-out, non-colliding item */ |
446 | ftotal = 0; | |
447 | skip_rep = 0; | |
448 | do { | |
449 | retry_descent = 0; | |
450 | in = bucket; /* initial bucket */ | |
451 | ||
452 | /* choose through intervening buckets */ | |
453 | flocal = 0; | |
454 | do { | |
b28813a6 | 455 | collide = 0; |
5ecc0a0f | 456 | retry_bucket = 0; |
e2b149cc | 457 | r = rep + parent_r; |
9fe07182 ID |
458 | /* r' = r + f_total */ |
459 | r += ftotal; | |
5ecc0a0f SW |
460 | |
461 | /* bucket choose */ | |
b28813a6 SW |
462 | if (in->size == 0) { |
463 | reject = 1; | |
464 | goto reject; | |
465 | } | |
48a163db | 466 | if (local_fallback_retries > 0 && |
546f04ef | 467 | flocal >= (in->size>>1) && |
48a163db | 468 | flocal > local_fallback_retries) |
5ecc0a0f SW |
469 | item = bucket_perm_choose(in, x, r); |
470 | else | |
471 | item = crush_bucket_choose(in, x, r); | |
a1f4895b SW |
472 | if (item >= map->max_devices) { |
473 | dprintk(" bad item %d\n", item); | |
474 | skip_rep = 1; | |
475 | break; | |
476 | } | |
5ecc0a0f SW |
477 | |
478 | /* desired type? */ | |
479 | if (item < 0) | |
480 | itemtype = map->buckets[-1-item]->type; | |
481 | else | |
482 | itemtype = 0; | |
483 | dprintk(" item %d type %d\n", item, itemtype); | |
484 | ||
485 | /* keep going? */ | |
486 | if (itemtype != type) { | |
a1f4895b SW |
487 | if (item >= 0 || |
488 | (-1-item) >= map->max_buckets) { | |
489 | dprintk(" bad item type %d\n", type); | |
490 | skip_rep = 1; | |
491 | break; | |
492 | } | |
5ecc0a0f | 493 | in = map->buckets[-1-item]; |
55bda7aa | 494 | retry_bucket = 1; |
5ecc0a0f SW |
495 | continue; |
496 | } | |
497 | ||
498 | /* collision? */ | |
5ecc0a0f SW |
499 | for (i = 0; i < outpos; i++) { |
500 | if (out[i] == item) { | |
501 | collide = 1; | |
502 | break; | |
503 | } | |
504 | } | |
505 | ||
a1a31e73 | 506 | reject = 0; |
7d7c1f61 | 507 | if (!collide && recurse_to_leaf) { |
a1a31e73 | 508 | if (item < 0) { |
e2b149cc ID |
509 | int sub_r; |
510 | if (vary_r) | |
511 | sub_r = r >> (vary_r-1); | |
512 | else | |
513 | sub_r = 0; | |
9fe07182 | 514 | if (crush_choose_firstn(map, |
a1a31e73 | 515 | map->buckets[-1-item], |
b3b33b0e | 516 | weight, weight_max, |
dc6ae6d8 | 517 | x, stable ? 1 : outpos+1, 0, |
45002267 | 518 | out2, outpos, count, |
2d8be0bc | 519 | recurse_tries, 0, |
48a163db ID |
520 | local_retries, |
521 | local_fallback_retries, | |
9fe07182 | 522 | 0, |
e2b149cc | 523 | vary_r, |
dc6ae6d8 | 524 | stable, |
e2b149cc ID |
525 | NULL, |
526 | sub_r) <= outpos) | |
a1a31e73 SW |
527 | /* didn't get leaf */ |
528 | reject = 1; | |
529 | } else { | |
530 | /* we already have a leaf! */ | |
531 | out2[outpos] = item; | |
532 | } | |
533 | } | |
534 | ||
535 | if (!reject) { | |
5ecc0a0f SW |
536 | /* out? */ |
537 | if (itemtype == 0) | |
538 | reject = is_out(map, weight, | |
b3b33b0e | 539 | weight_max, |
5ecc0a0f SW |
540 | item, x); |
541 | else | |
542 | reject = 0; | |
543 | } | |
544 | ||
b28813a6 | 545 | reject: |
5ecc0a0f SW |
546 | if (reject || collide) { |
547 | ftotal++; | |
548 | flocal++; | |
549 | ||
48a163db | 550 | if (collide && flocal <= local_retries) |
5ecc0a0f SW |
551 | /* retry locally a few times */ |
552 | retry_bucket = 1; | |
48a163db ID |
553 | else if (local_fallback_retries > 0 && |
554 | flocal <= in->size + local_fallback_retries) | |
5ecc0a0f SW |
555 | /* exhaustive bucket search */ |
556 | retry_bucket = 1; | |
48a163db | 557 | else if (ftotal < tries) |
5ecc0a0f SW |
558 | /* then retry descent */ |
559 | retry_descent = 1; | |
560 | else | |
561 | /* else give up */ | |
562 | skip_rep = 1; | |
563 | dprintk(" reject %d collide %d " | |
8b12d47b | 564 | "ftotal %u flocal %u\n", |
5ecc0a0f SW |
565 | reject, collide, ftotal, |
566 | flocal); | |
567 | } | |
568 | } while (retry_bucket); | |
569 | } while (retry_descent); | |
570 | ||
571 | if (skip_rep) { | |
9fe07182 ID |
572 | dprintk("skip rep\n"); |
573 | continue; | |
5ecc0a0f SW |
574 | } |
575 | ||
a1a31e73 | 576 | dprintk("CHOOSE got %d\n", item); |
5ecc0a0f SW |
577 | out[outpos] = item; |
578 | outpos++; | |
45002267 | 579 | count--; |
b459be73 ID |
580 | #ifndef __KERNEL__ |
581 | if (map->choose_tries && ftotal <= map->choose_total_tries) | |
582 | map->choose_tries[ftotal]++; | |
583 | #endif | |
5ecc0a0f SW |
584 | } |
585 | ||
a1a31e73 | 586 | dprintk("CHOOSE returns %d\n", outpos); |
5ecc0a0f SW |
587 | return outpos; |
588 | } | |
589 | ||
590 | ||
9a3b490a | 591 | /** |
9fe07182 | 592 | * crush_choose_indep: alternative breadth-first positionally stable mapping |
9a3b490a ID |
593 | * |
594 | */ | |
595 | static void crush_choose_indep(const struct crush_map *map, | |
be3226ac ID |
596 | struct crush_bucket *bucket, |
597 | const __u32 *weight, int weight_max, | |
ab4ce2b5 | 598 | int x, int left, int numrep, int type, |
be3226ac | 599 | int *out, int outpos, |
2d8be0bc ID |
600 | unsigned int tries, |
601 | unsigned int recurse_tries, | |
be3226ac | 602 | int recurse_to_leaf, |
41586081 ID |
603 | int *out2, |
604 | int parent_r) | |
9a3b490a ID |
605 | { |
606 | struct crush_bucket *in = bucket; | |
ab4ce2b5 | 607 | int endpos = outpos + left; |
9a3b490a ID |
608 | int rep; |
609 | unsigned int ftotal; | |
610 | int r; | |
611 | int i; | |
612 | int item = 0; | |
613 | int itemtype; | |
614 | int collide; | |
615 | ||
616 | dprintk("CHOOSE%s INDEP bucket %d x %d outpos %d numrep %d\n", recurse_to_leaf ? "_LEAF" : "", | |
617 | bucket->id, x, outpos, numrep); | |
618 | ||
619 | /* initially my result is undefined */ | |
ab4ce2b5 | 620 | for (rep = outpos; rep < endpos; rep++) { |
9a3b490a ID |
621 | out[rep] = CRUSH_ITEM_UNDEF; |
622 | if (out2) | |
623 | out2[rep] = CRUSH_ITEM_UNDEF; | |
624 | } | |
625 | ||
2d8be0bc | 626 | for (ftotal = 0; left > 0 && ftotal < tries; ftotal++) { |
b459be73 ID |
627 | #ifdef DEBUG_INDEP |
628 | if (out2 && ftotal) { | |
629 | dprintk("%u %d a: ", ftotal, left); | |
630 | for (rep = outpos; rep < endpos; rep++) { | |
631 | dprintk(" %d", out[rep]); | |
632 | } | |
633 | dprintk("\n"); | |
634 | dprintk("%u %d b: ", ftotal, left); | |
635 | for (rep = outpos; rep < endpos; rep++) { | |
636 | dprintk(" %d", out2[rep]); | |
637 | } | |
638 | dprintk("\n"); | |
639 | } | |
640 | #endif | |
ab4ce2b5 | 641 | for (rep = outpos; rep < endpos; rep++) { |
9a3b490a ID |
642 | if (out[rep] != CRUSH_ITEM_UNDEF) |
643 | continue; | |
644 | ||
645 | in = bucket; /* initial bucket */ | |
646 | ||
647 | /* choose through intervening buckets */ | |
648 | for (;;) { | |
3102b0a5 ID |
649 | /* note: we base the choice on the position |
650 | * even in the nested call. that means that | |
651 | * if the first layer chooses the same bucket | |
652 | * in a different position, we will tend to | |
653 | * choose a different item in that bucket. | |
654 | * this will involve more devices in data | |
655 | * movement and tend to distribute the load. | |
656 | */ | |
41586081 | 657 | r = rep + parent_r; |
9a3b490a ID |
658 | |
659 | /* be careful */ | |
660 | if (in->alg == CRUSH_BUCKET_UNIFORM && | |
661 | in->size % numrep == 0) | |
662 | /* r'=r+(n+1)*f_total */ | |
663 | r += (numrep+1) * ftotal; | |
664 | else | |
665 | /* r' = r + n*f_total */ | |
666 | r += numrep * ftotal; | |
667 | ||
668 | /* bucket choose */ | |
669 | if (in->size == 0) { | |
670 | dprintk(" empty bucket\n"); | |
671 | break; | |
672 | } | |
673 | ||
674 | item = crush_bucket_choose(in, x, r); | |
675 | if (item >= map->max_devices) { | |
676 | dprintk(" bad item %d\n", item); | |
677 | out[rep] = CRUSH_ITEM_NONE; | |
678 | if (out2) | |
679 | out2[rep] = CRUSH_ITEM_NONE; | |
680 | left--; | |
681 | break; | |
682 | } | |
683 | ||
684 | /* desired type? */ | |
685 | if (item < 0) | |
686 | itemtype = map->buckets[-1-item]->type; | |
687 | else | |
688 | itemtype = 0; | |
689 | dprintk(" item %d type %d\n", item, itemtype); | |
690 | ||
691 | /* keep going? */ | |
692 | if (itemtype != type) { | |
693 | if (item >= 0 || | |
694 | (-1-item) >= map->max_buckets) { | |
695 | dprintk(" bad item type %d\n", type); | |
696 | out[rep] = CRUSH_ITEM_NONE; | |
697 | if (out2) | |
698 | out2[rep] = | |
699 | CRUSH_ITEM_NONE; | |
700 | left--; | |
701 | break; | |
702 | } | |
703 | in = map->buckets[-1-item]; | |
704 | continue; | |
705 | } | |
706 | ||
707 | /* collision? */ | |
708 | collide = 0; | |
ab4ce2b5 | 709 | for (i = outpos; i < endpos; i++) { |
9a3b490a ID |
710 | if (out[i] == item) { |
711 | collide = 1; | |
712 | break; | |
713 | } | |
714 | } | |
715 | if (collide) | |
716 | break; | |
717 | ||
718 | if (recurse_to_leaf) { | |
719 | if (item < 0) { | |
720 | crush_choose_indep(map, | |
be3226ac ID |
721 | map->buckets[-1-item], |
722 | weight, weight_max, | |
723 | x, 1, numrep, 0, | |
724 | out2, rep, | |
2d8be0bc | 725 | recurse_tries, 0, |
be3226ac | 726 | 0, NULL, r); |
9a3b490a ID |
727 | if (out2[rep] == CRUSH_ITEM_NONE) { |
728 | /* placed nothing; no leaf */ | |
729 | break; | |
730 | } | |
731 | } else { | |
732 | /* we already have a leaf! */ | |
733 | out2[rep] = item; | |
734 | } | |
735 | } | |
736 | ||
737 | /* out? */ | |
738 | if (itemtype == 0 && | |
739 | is_out(map, weight, weight_max, item, x)) | |
740 | break; | |
741 | ||
742 | /* yay! */ | |
743 | out[rep] = item; | |
744 | left--; | |
745 | break; | |
746 | } | |
747 | } | |
748 | } | |
ab4ce2b5 | 749 | for (rep = outpos; rep < endpos; rep++) { |
9a3b490a ID |
750 | if (out[rep] == CRUSH_ITEM_UNDEF) { |
751 | out[rep] = CRUSH_ITEM_NONE; | |
752 | } | |
753 | if (out2 && out2[rep] == CRUSH_ITEM_UNDEF) { | |
754 | out2[rep] = CRUSH_ITEM_NONE; | |
755 | } | |
756 | } | |
b459be73 ID |
757 | #ifndef __KERNEL__ |
758 | if (map->choose_tries && ftotal <= map->choose_total_tries) | |
759 | map->choose_tries[ftotal]++; | |
760 | #endif | |
761 | #ifdef DEBUG_INDEP | |
762 | if (out2) { | |
763 | dprintk("%u %d a: ", ftotal, left); | |
764 | for (rep = outpos; rep < endpos; rep++) { | |
765 | dprintk(" %d", out[rep]); | |
766 | } | |
767 | dprintk("\n"); | |
768 | dprintk("%u %d b: ", ftotal, left); | |
769 | for (rep = outpos; rep < endpos; rep++) { | |
770 | dprintk(" %d", out2[rep]); | |
771 | } | |
772 | dprintk("\n"); | |
773 | } | |
774 | #endif | |
9a3b490a ID |
775 | } |
776 | ||
5ecc0a0f SW |
777 | /** |
778 | * crush_do_rule - calculate a mapping with the given input and rule | |
779 | * @map: the crush_map | |
780 | * @ruleno: the rule id | |
781 | * @x: hash input | |
782 | * @result: pointer to result vector | |
783 | * @result_max: maximum result size | |
b3b33b0e ID |
784 | * @weight: weight vector (for map leaves) |
785 | * @weight_max: size of weight vector | |
e8ef19c4 | 786 | * @scratch: scratch vector for private use; must be >= 3 * result_max |
5ecc0a0f | 787 | */ |
8b12d47b | 788 | int crush_do_rule(const struct crush_map *map, |
5ecc0a0f | 789 | int ruleno, int x, int *result, int result_max, |
e8ef19c4 ID |
790 | const __u32 *weight, int weight_max, |
791 | int *scratch) | |
5ecc0a0f SW |
792 | { |
793 | int result_len; | |
e8ef19c4 ID |
794 | int *a = scratch; |
795 | int *b = scratch + result_max; | |
796 | int *c = scratch + result_max*2; | |
5ecc0a0f SW |
797 | int recurse_to_leaf; |
798 | int *w; | |
799 | int wsize = 0; | |
800 | int *o; | |
801 | int osize; | |
802 | int *tmp; | |
803 | struct crush_rule *rule; | |
8b12d47b | 804 | __u32 step; |
5ecc0a0f SW |
805 | int i, j; |
806 | int numrep; | |
45002267 | 807 | int out_size; |
48a163db ID |
808 | /* |
809 | * the original choose_total_tries value was off by one (it | |
810 | * counted "retries" and not "tries"). add one. | |
811 | */ | |
812 | int choose_tries = map->choose_total_tries + 1; | |
f18650ac | 813 | int choose_leaf_tries = 0; |
48a163db ID |
814 | /* |
815 | * the local tries values were counted as "retries", though, | |
816 | * and need no adjustment | |
817 | */ | |
818 | int choose_local_retries = map->choose_local_tries; | |
819 | int choose_local_fallback_retries = map->choose_local_fallback_tries; | |
5ecc0a0f | 820 | |
e2b149cc | 821 | int vary_r = map->chooseleaf_vary_r; |
dc6ae6d8 | 822 | int stable = map->chooseleaf_stable; |
e2b149cc | 823 | |
a1f4895b SW |
824 | if ((__u32)ruleno >= map->max_rules) { |
825 | dprintk(" bad ruleno %d\n", ruleno); | |
826 | return 0; | |
827 | } | |
5ecc0a0f SW |
828 | |
829 | rule = map->rules[ruleno]; | |
830 | result_len = 0; | |
831 | w = a; | |
832 | o = b; | |
833 | ||
5ecc0a0f | 834 | for (step = 0; step < rule->len; step++) { |
8f99c85b | 835 | int firstn = 0; |
0668216e SW |
836 | struct crush_rule_step *curstep = &rule->steps[step]; |
837 | ||
0668216e | 838 | switch (curstep->op) { |
5ecc0a0f | 839 | case CRUSH_RULE_TAKE: |
8f529795 ID |
840 | if ((curstep->arg1 >= 0 && |
841 | curstep->arg1 < map->max_devices) || | |
56a4f309 ID |
842 | (-1-curstep->arg1 >= 0 && |
843 | -1-curstep->arg1 < map->max_buckets && | |
8f529795 ID |
844 | map->buckets[-1-curstep->arg1])) { |
845 | w[0] = curstep->arg1; | |
846 | wsize = 1; | |
847 | } else { | |
848 | dprintk(" bad take value %d\n", curstep->arg1); | |
849 | } | |
5ecc0a0f SW |
850 | break; |
851 | ||
cc10df4a ID |
852 | case CRUSH_RULE_SET_CHOOSE_TRIES: |
853 | if (curstep->arg1 > 0) | |
854 | choose_tries = curstep->arg1; | |
855 | break; | |
856 | ||
917edad5 | 857 | case CRUSH_RULE_SET_CHOOSELEAF_TRIES: |
be3226ac ID |
858 | if (curstep->arg1 > 0) |
859 | choose_leaf_tries = curstep->arg1; | |
860 | break; | |
861 | ||
f046bf92 | 862 | case CRUSH_RULE_SET_CHOOSE_LOCAL_TRIES: |
6ed1002f | 863 | if (curstep->arg1 >= 0) |
48a163db | 864 | choose_local_retries = curstep->arg1; |
f046bf92 ID |
865 | break; |
866 | ||
867 | case CRUSH_RULE_SET_CHOOSE_LOCAL_FALLBACK_TRIES: | |
6ed1002f | 868 | if (curstep->arg1 >= 0) |
48a163db | 869 | choose_local_fallback_retries = curstep->arg1; |
f046bf92 | 870 | break; |
d83ed858 ID |
871 | |
872 | case CRUSH_RULE_SET_CHOOSELEAF_VARY_R: | |
873 | if (curstep->arg1 >= 0) | |
874 | vary_r = curstep->arg1; | |
875 | break; | |
f046bf92 | 876 | |
dc6ae6d8 ID |
877 | case CRUSH_RULE_SET_CHOOSELEAF_STABLE: |
878 | if (curstep->arg1 >= 0) | |
879 | stable = curstep->arg1; | |
880 | break; | |
881 | ||
917edad5 | 882 | case CRUSH_RULE_CHOOSELEAF_FIRSTN: |
5ecc0a0f SW |
883 | case CRUSH_RULE_CHOOSE_FIRSTN: |
884 | firstn = 1; | |
0668216e | 885 | /* fall through */ |
917edad5 | 886 | case CRUSH_RULE_CHOOSELEAF_INDEP: |
5ecc0a0f | 887 | case CRUSH_RULE_CHOOSE_INDEP: |
a1f4895b SW |
888 | if (wsize == 0) |
889 | break; | |
5ecc0a0f SW |
890 | |
891 | recurse_to_leaf = | |
0668216e | 892 | curstep->op == |
917edad5 | 893 | CRUSH_RULE_CHOOSELEAF_FIRSTN || |
0668216e | 894 | curstep->op == |
917edad5 | 895 | CRUSH_RULE_CHOOSELEAF_INDEP; |
5ecc0a0f SW |
896 | |
897 | /* reset output */ | |
898 | osize = 0; | |
899 | ||
900 | for (i = 0; i < wsize; i++) { | |
f224a691 | 901 | int bno; |
5ecc0a0f SW |
902 | /* |
903 | * see CRUSH_N, CRUSH_N_MINUS macros. | |
904 | * basically, numrep <= 0 means relative to | |
905 | * the provided result_max | |
906 | */ | |
0668216e | 907 | numrep = curstep->arg1; |
5ecc0a0f SW |
908 | if (numrep <= 0) { |
909 | numrep += result_max; | |
910 | if (numrep <= 0) | |
911 | continue; | |
912 | } | |
913 | j = 0; | |
f224a691 ID |
914 | /* make sure bucket id is valid */ |
915 | bno = -1 - w[i]; | |
916 | if (bno < 0 || bno >= map->max_buckets) { | |
917 | /* w[i] is probably CRUSH_ITEM_NONE */ | |
918 | dprintk(" bad w[i] %d\n", w[i]); | |
919 | continue; | |
920 | } | |
9a3b490a | 921 | if (firstn) { |
d390bb2a ID |
922 | int recurse_tries; |
923 | if (choose_leaf_tries) | |
924 | recurse_tries = | |
925 | choose_leaf_tries; | |
926 | else if (map->chooseleaf_descend_once) | |
927 | recurse_tries = 1; | |
928 | else | |
929 | recurse_tries = choose_tries; | |
9fe07182 ID |
930 | osize += crush_choose_firstn( |
931 | map, | |
f224a691 | 932 | map->buckets[bno], |
9fe07182 ID |
933 | weight, weight_max, |
934 | x, numrep, | |
935 | curstep->arg2, | |
936 | o+osize, j, | |
45002267 | 937 | result_max-osize, |
f18650ac | 938 | choose_tries, |
d390bb2a | 939 | recurse_tries, |
48a163db ID |
940 | choose_local_retries, |
941 | choose_local_fallback_retries, | |
9fe07182 | 942 | recurse_to_leaf, |
e2b149cc | 943 | vary_r, |
dc6ae6d8 | 944 | stable, |
e2b149cc ID |
945 | c+osize, |
946 | 0); | |
9a3b490a | 947 | } else { |
45002267 | 948 | out_size = ((numrep < (result_max-osize)) ? |
b459be73 | 949 | numrep : (result_max-osize)); |
9fe07182 ID |
950 | crush_choose_indep( |
951 | map, | |
f224a691 | 952 | map->buckets[bno], |
9fe07182 | 953 | weight, weight_max, |
45002267 | 954 | x, out_size, numrep, |
9fe07182 ID |
955 | curstep->arg2, |
956 | o+osize, j, | |
f18650ac | 957 | choose_tries, |
d390bb2a ID |
958 | choose_leaf_tries ? |
959 | choose_leaf_tries : 1, | |
9fe07182 | 960 | recurse_to_leaf, |
41586081 ID |
961 | c+osize, |
962 | 0); | |
45002267 | 963 | osize += out_size; |
9a3b490a | 964 | } |
5ecc0a0f SW |
965 | } |
966 | ||
967 | if (recurse_to_leaf) | |
968 | /* copy final _leaf_ values to output set */ | |
969 | memcpy(o, c, osize*sizeof(*o)); | |
970 | ||
2a4ba74e | 971 | /* swap o and w arrays */ |
5ecc0a0f SW |
972 | tmp = o; |
973 | o = w; | |
974 | w = tmp; | |
975 | wsize = osize; | |
976 | break; | |
977 | ||
978 | ||
979 | case CRUSH_RULE_EMIT: | |
980 | for (i = 0; i < wsize && result_len < result_max; i++) { | |
981 | result[result_len] = w[i]; | |
982 | result_len++; | |
983 | } | |
984 | wsize = 0; | |
985 | break; | |
986 | ||
987 | default: | |
a1f4895b SW |
988 | dprintk(" unknown op %d at step %d\n", |
989 | curstep->op, step); | |
990 | break; | |
5ecc0a0f SW |
991 | } |
992 | } | |
f1932fc1 | 993 | return result_len; |
5ecc0a0f | 994 | } |