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fix a kmap leak in virtio_console
[linux/fpc-iii.git] / net / ceph / crush / mapper.c
blobb703790b4e44788e109bb91ab61f272015000654
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 <linux/crush/crush.h>
22 #include <linux/crush/hash.h>
23 #include <linux/crush/mapper.h>
24
25 /*
26 * Implement the core CRUSH mapping algorithm.
27 */
28
29 /**
30 * crush_find_rule - find a crush_rule id for a given ruleset, type, and size.
31 * @map: the crush_map
32 * @ruleset: the storage ruleset id (user defined)
33 * @type: storage ruleset type (user defined)
34 * @size: output set size
35 */
36 int crush_find_rule(const struct crush_map *map, int ruleset, int type, int size)
37 {
38 __u32 i;
39
40 for (i = 0; i < map->max_rules; i++) {
41 if (map->rules[i] &&
42 map->rules[i]->mask.ruleset == ruleset &&
43 map->rules[i]->mask.type == type &&
44 map->rules[i]->mask.min_size <= size &&
45 map->rules[i]->mask.max_size >= size)
46 return i;
47 }
48 return -1;
49 }
50
51
52 /*
53 * bucket choose methods
54 *
55 * For each bucket algorithm, we have a "choose" method that, given a
56 * crush input @x and replica position (usually, position in output set) @r,
57 * will produce an item in the bucket.
58 */
59
60 /*
61 * Choose based on a random permutation of the bucket.
62 *
63 * We used to use some prime number arithmetic to do this, but it
64 * wasn't very random, and had some other bad behaviors. Instead, we
65 * calculate an actual random permutation of the bucket members.
66 * Since this is expensive, we optimize for the r=0 case, which
67 * captures the vast majority of calls.
68 */
69 static int bucket_perm_choose(struct crush_bucket *bucket,
70 int x, int r)
71 {
72 unsigned int pr = r % bucket->size;
73 unsigned int i, s;
74
75 /* start a new permutation if @x has changed */
76 if (bucket->perm_x != (__u32)x || bucket->perm_n == 0) {
77 dprintk("bucket %d new x=%d\n", bucket->id, x);
78 bucket->perm_x = x;
79
80 /* optimize common r=0 case */
81 if (pr == 0) {
82 s = crush_hash32_3(bucket->hash, x, bucket->id, 0) %
83 bucket->size;
84 bucket->perm[0] = s;
85 bucket->perm_n = 0xffff; /* magic value, see below */
86 goto out;
87 }
88
89 for (i = 0; i < bucket->size; i++)
90 bucket->perm[i] = i;
91 bucket->perm_n = 0;
92 } else if (bucket->perm_n == 0xffff) {
93 /* clean up after the r=0 case above */
94 for (i = 1; i < bucket->size; i++)
95 bucket->perm[i] = i;
96 bucket->perm[bucket->perm[0]] = 0;
97 bucket->perm_n = 1;
98 }
99
100 /* calculate permutation up to pr */
101 for (i = 0; i < bucket->perm_n; i++)
102 dprintk(" perm_choose have %d: %d\n", i, bucket->perm[i]);
103 while (bucket->perm_n <= pr) {
104 unsigned int p = bucket->perm_n;
105 /* no point in swapping the final entry */
106 if (p < bucket->size - 1) {
107 i = crush_hash32_3(bucket->hash, x, bucket->id, p) %
108 (bucket->size - p);
109 if (i) {
110 unsigned int t = bucket->perm[p + i];
111 bucket->perm[p + i] = bucket->perm[p];
112 bucket->perm[p] = t;
113 }
114 dprintk(" perm_choose swap %d with %d\n", p, p+i);
115 }
116 bucket->perm_n++;
117 }
118 for (i = 0; i < bucket->size; i++)
119 dprintk(" perm_choose %d: %d\n", i, bucket->perm[i]);
120
121 s = bucket->perm[pr];
122 out:
123 dprintk(" perm_choose %d sz=%d x=%d r=%d (%d) s=%d\n", bucket->id,
124 bucket->size, x, r, pr, s);
125 return bucket->items[s];
126 }
127
128 /* uniform */
129 static int bucket_uniform_choose(struct crush_bucket_uniform *bucket,
130 int x, int r)
131 {
132 return bucket_perm_choose(&bucket->h, x, r);
133 }
134
135 /* list */
136 static int bucket_list_choose(struct crush_bucket_list *bucket,
137 int x, int r)
138 {
139 int i;
140
141 for (i = bucket->h.size-1; i >= 0; i--) {
142 __u64 w = crush_hash32_4(bucket->h.hash,x, bucket->h.items[i],
143 r, bucket->h.id);
144 w &= 0xffff;
145 dprintk("list_choose i=%d x=%d r=%d item %d weight %x "
146 "sw %x rand %llx",
147 i, x, r, bucket->h.items[i], bucket->item_weights[i],
148 bucket->sum_weights[i], w);
149 w *= bucket->sum_weights[i];
150 w = w >> 16;
151 /*dprintk(" scaled %llx\n", w);*/
152 if (w < bucket->item_weights[i])
153 return bucket->h.items[i];
154 }
155
156 dprintk("bad list sums for bucket %d\n", bucket->h.id);
157 return bucket->h.items[0];
158 }
159
160
161 /* (binary) tree */
162 static int height(int n)
163 {
164 int h = 0;
165 while ((n & 1) == 0) {
166 h++;
167 n = n >> 1;
168 }
169 return h;
170 }
171
172 static int left(int x)
173 {
174 int h = height(x);
175 return x - (1 << (h-1));
176 }
177
178 static int right(int x)
179 {
180 int h = height(x);
181 return x + (1 << (h-1));
182 }
183
184 static int terminal(int x)
185 {
186 return x & 1;
187 }
188
189 static int bucket_tree_choose(struct crush_bucket_tree *bucket,
190 int x, int r)
191 {
192 int n;
193 __u32 w;
194 __u64 t;
195
196 /* start at root */
197 n = bucket->num_nodes >> 1;
198
199 while (!terminal(n)) {
200 int l;
201 /* pick point in [0, w) */
202 w = bucket->node_weights[n];
203 t = (__u64)crush_hash32_4(bucket->h.hash, x, n, r,
204 bucket->h.id) * (__u64)w;
205 t = t >> 32;
206
207 /* descend to the left or right? */
208 l = left(n);
209 if (t < bucket->node_weights[l])
210 n = l;
211 else
212 n = right(n);
213 }
214
215 return bucket->h.items[n >> 1];
216 }
217
218
219 /* straw */
220
221 static int bucket_straw_choose(struct crush_bucket_straw *bucket,
222 int x, int r)
223 {
224 __u32 i;
225 int high = 0;
226 __u64 high_draw = 0;
227 __u64 draw;
228
229 for (i = 0; i < bucket->h.size; i++) {
230 draw = crush_hash32_3(bucket->h.hash, x, bucket->h.items[i], r);
231 draw &= 0xffff;
232 draw *= bucket->straws[i];
233 if (i == 0 || draw > high_draw) {
234 high = i;
235 high_draw = draw;
236 }
237 }
238 return bucket->h.items[high];
239 }
240
241 static int crush_bucket_choose(struct crush_bucket *in, int x, int r)
242 {
243 dprintk(" crush_bucket_choose %d x=%d r=%d\n", in->id, x, r);
244 BUG_ON(in->size == 0);
245 switch (in->alg) {
246 case CRUSH_BUCKET_UNIFORM:
247 return bucket_uniform_choose((struct crush_bucket_uniform *)in,
248 x, r);
249 case CRUSH_BUCKET_LIST:
250 return bucket_list_choose((struct crush_bucket_list *)in,
251 x, r);
252 case CRUSH_BUCKET_TREE:
253 return bucket_tree_choose((struct crush_bucket_tree *)in,
254 x, r);
255 case CRUSH_BUCKET_STRAW:
256 return bucket_straw_choose((struct crush_bucket_straw *)in,
257 x, r);
258 default:
259 dprintk("unknown bucket %d alg %d\n", in->id, in->alg);
260 return in->items[0];
261 }
262 }
263
264 /*
265 * true if device is marked "out" (failed, fully offloaded)
266 * of the cluster
267 */
268 static int is_out(const struct crush_map *map,
269 const __u32 *weight, int weight_max,
270 int item, int x)
271 {
272 if (item >= weight_max)
273 return 1;
274 if (weight[item] >= 0x10000)
275 return 0;
276 if (weight[item] == 0)
277 return 1;
278 if ((crush_hash32_2(CRUSH_HASH_RJENKINS1, x, item) & 0xffff)
279 < weight[item])
280 return 0;
281 return 1;
282 }
283
284 /**
285 * crush_choose_firstn - choose numrep distinct items of given type
286 * @map: the crush_map
287 * @bucket: the bucket we are choose an item from
288 * @x: crush input value
289 * @numrep: the number of items to choose
290 * @type: the type of item to choose
291 * @out: pointer to output vector
292 * @outpos: our position in that vector
293 * @tries: number of attempts to make
294 * @recurse_tries: number of attempts to have recursive chooseleaf make
295 * @local_tries: localized retries
296 * @local_fallback_tries: localized fallback retries
297 * @recurse_to_leaf: true if we want one device under each item of given type (chooseleaf instead of choose)
298 * @out2: second output vector for leaf items (if @recurse_to_leaf)
299 */
300 static int crush_choose_firstn(const struct crush_map *map,
301 struct crush_bucket *bucket,
302 const __u32 *weight, int weight_max,
303 int x, int numrep, int type,
304 int *out, int outpos,
305 unsigned int tries,
306 unsigned int recurse_tries,
307 unsigned int local_tries,
308 unsigned int local_fallback_tries,
309 int recurse_to_leaf,
310 int *out2)
311 {
312 int rep;
313 unsigned int ftotal, flocal;
314 int retry_descent, retry_bucket, skip_rep;
315 struct crush_bucket *in = bucket;
316 int r;
317 int i;
318 int item = 0;
319 int itemtype;
320 int collide, reject;
321
322 dprintk("CHOOSE%s bucket %d x %d outpos %d numrep %d\n", recurse_to_leaf ? "_LEAF" : "",
323 bucket->id, x, outpos, numrep);
324
325 for (rep = outpos; rep < numrep; rep++) {
326 /* keep trying until we get a non-out, non-colliding item */
327 ftotal = 0;
328 skip_rep = 0;
329 do {
330 retry_descent = 0;
331 in = bucket; /* initial bucket */
332
333 /* choose through intervening buckets */
334 flocal = 0;
335 do {
336 collide = 0;
337 retry_bucket = 0;
338 r = rep;
339 /* r' = r + f_total */
340 r += ftotal;
341
342 /* bucket choose */
343 if (in->size == 0) {
344 reject = 1;
345 goto reject;
346 }
347 if (local_fallback_tries > 0 &&
348 flocal >= (in->size>>1) &&
349 flocal > local_fallback_tries)
350 item = bucket_perm_choose(in, x, r);
351 else
352 item = crush_bucket_choose(in, x, r);
353 if (item >= map->max_devices) {
354 dprintk(" bad item %d\n", item);
355 skip_rep = 1;
356 break;
357 }
358
359 /* desired type? */
360 if (item < 0)
361 itemtype = map->buckets[-1-item]->type;
362 else
363 itemtype = 0;
364 dprintk(" item %d type %d\n", item, itemtype);
365
366 /* keep going? */
367 if (itemtype != type) {
368 if (item >= 0 ||
369 (-1-item) >= map->max_buckets) {
370 dprintk(" bad item type %d\n", type);
371 skip_rep = 1;
372 break;
373 }
374 in = map->buckets[-1-item];
375 retry_bucket = 1;
376 continue;
377 }
378
379 /* collision? */
380 for (i = 0; i < outpos; i++) {
381 if (out[i] == item) {
382 collide = 1;
383 break;
384 }
385 }
386
387 reject = 0;
388 if (!collide && recurse_to_leaf) {
389 if (item < 0) {
390 if (crush_choose_firstn(map,
391 map->buckets[-1-item],
392 weight, weight_max,
393 x, outpos+1, 0,
394 out2, outpos,
395 recurse_tries, 0,
396 local_tries,
397 local_fallback_tries,
398 0,
399 NULL) <= outpos)
400 /* didn't get leaf */
401 reject = 1;
402 } else {
403 /* we already have a leaf! */
404 out2[outpos] = item;
405 }
406 }
407
408 if (!reject) {
409 /* out? */
410 if (itemtype == 0)
411 reject = is_out(map, weight,
412 weight_max,
413 item, x);
414 else
415 reject = 0;
416 }
417
418 reject:
419 if (reject || collide) {
420 ftotal++;
421 flocal++;
422
423 if (collide && flocal <= local_tries)
424 /* retry locally a few times */
425 retry_bucket = 1;
426 else if (local_fallback_tries > 0 &&
427 flocal <= in->size + local_fallback_tries)
428 /* exhaustive bucket search */
429 retry_bucket = 1;
430 else if (ftotal <= tries)
431 /* then retry descent */
432 retry_descent = 1;
433 else
434 /* else give up */
435 skip_rep = 1;
436 dprintk(" reject %d collide %d "
437 "ftotal %u flocal %u\n",
438 reject, collide, ftotal,
439 flocal);
440 }
441 } while (retry_bucket);
442 } while (retry_descent);
443
444 if (skip_rep) {
445 dprintk("skip rep\n");
446 continue;
447 }
448
449 dprintk("CHOOSE got %d\n", item);
450 out[outpos] = item;
451 outpos++;
452 }
453
454 dprintk("CHOOSE returns %d\n", outpos);
455 return outpos;
456 }
457
458
459 /**
460 * crush_choose_indep: alternative breadth-first positionally stable mapping
461 *
462 */
463 static void crush_choose_indep(const struct crush_map *map,
464 struct crush_bucket *bucket,
465 const __u32 *weight, int weight_max,
466 int x, int left, int numrep, int type,
467 int *out, int outpos,
468 unsigned int tries,
469 unsigned int recurse_tries,
470 int recurse_to_leaf,
471 int *out2,
472 int parent_r)
473 {
474 struct crush_bucket *in = bucket;
475 int endpos = outpos + left;
476 int rep;
477 unsigned int ftotal;
478 int r;
479 int i;
480 int item = 0;
481 int itemtype;
482 int collide;
483
484 dprintk("CHOOSE%s INDEP bucket %d x %d outpos %d numrep %d\n", recurse_to_leaf ? "_LEAF" : "",
485 bucket->id, x, outpos, numrep);
486
487 /* initially my result is undefined */
488 for (rep = outpos; rep < endpos; rep++) {
489 out[rep] = CRUSH_ITEM_UNDEF;
490 if (out2)
491 out2[rep] = CRUSH_ITEM_UNDEF;
492 }
493
494 for (ftotal = 0; left > 0 && ftotal < tries; ftotal++) {
495 for (rep = outpos; rep < endpos; rep++) {
496 if (out[rep] != CRUSH_ITEM_UNDEF)
497 continue;
498
499 in = bucket; /* initial bucket */
500
501 /* choose through intervening buckets */
502 for (;;) {
503 /* note: we base the choice on the position
504 * even in the nested call. that means that
505 * if the first layer chooses the same bucket
506 * in a different position, we will tend to
507 * choose a different item in that bucket.
508 * this will involve more devices in data
509 * movement and tend to distribute the load.
510 */
511 r = rep + parent_r;
512
513 /* be careful */
514 if (in->alg == CRUSH_BUCKET_UNIFORM &&
515 in->size % numrep == 0)
516 /* r'=r+(n+1)*f_total */
517 r += (numrep+1) * ftotal;
518 else
519 /* r' = r + n*f_total */
520 r += numrep * ftotal;
521
522 /* bucket choose */
523 if (in->size == 0) {
524 dprintk(" empty bucket\n");
525 break;
526 }
527
528 item = crush_bucket_choose(in, x, r);
529 if (item >= map->max_devices) {
530 dprintk(" bad item %d\n", item);
531 out[rep] = CRUSH_ITEM_NONE;
532 if (out2)
533 out2[rep] = CRUSH_ITEM_NONE;
534 left--;
535 break;
536 }
537
538 /* desired type? */
539 if (item < 0)
540 itemtype = map->buckets[-1-item]->type;
541 else
542 itemtype = 0;
543 dprintk(" item %d type %d\n", item, itemtype);
544
545 /* keep going? */
546 if (itemtype != type) {
547 if (item >= 0 ||
548 (-1-item) >= map->max_buckets) {
549 dprintk(" bad item type %d\n", type);
550 out[rep] = CRUSH_ITEM_NONE;
551 if (out2)
552 out2[rep] =
553 CRUSH_ITEM_NONE;
554 left--;
555 break;
556 }
557 in = map->buckets[-1-item];
558 continue;
559 }
560
561 /* collision? */
562 collide = 0;
563 for (i = outpos; i < endpos; i++) {
564 if (out[i] == item) {
565 collide = 1;
566 break;
567 }
568 }
569 if (collide)
570 break;
571
572 if (recurse_to_leaf) {
573 if (item < 0) {
574 crush_choose_indep(map,
575 map->buckets[-1-item],
576 weight, weight_max,
577 x, 1, numrep, 0,
578 out2, rep,
579 recurse_tries, 0,
580 0, NULL, r);
581 if (out2[rep] == CRUSH_ITEM_NONE) {
582 /* placed nothing; no leaf */
583 break;
584 }
585 } else {
586 /* we already have a leaf! */
587 out2[rep] = item;
588 }
589 }
590
591 /* out? */
592 if (itemtype == 0 &&
593 is_out(map, weight, weight_max, item, x))
594 break;
595
596 /* yay! */
597 out[rep] = item;
598 left--;
599 break;
600 }
601 }
602 }
603 for (rep = outpos; rep < endpos; rep++) {
604 if (out[rep] == CRUSH_ITEM_UNDEF) {
605 out[rep] = CRUSH_ITEM_NONE;
606 }
607 if (out2 && out2[rep] == CRUSH_ITEM_UNDEF) {
608 out2[rep] = CRUSH_ITEM_NONE;
609 }
610 }
611 }
612
613 /**
614 * crush_do_rule - calculate a mapping with the given input and rule
615 * @map: the crush_map
616 * @ruleno: the rule id
617 * @x: hash input
618 * @result: pointer to result vector
619 * @result_max: maximum result size
620 * @weight: weight vector (for map leaves)
621 * @weight_max: size of weight vector
622 * @scratch: scratch vector for private use; must be >= 3 * result_max
623 */
624 int crush_do_rule(const struct crush_map *map,
625 int ruleno, int x, int *result, int result_max,
626 const __u32 *weight, int weight_max,
627 int *scratch)
628 {
629 int result_len;
630 int *a = scratch;
631 int *b = scratch + result_max;
632 int *c = scratch + result_max*2;
633 int recurse_to_leaf;
634 int *w;
635 int wsize = 0;
636 int *o;
637 int osize;
638 int *tmp;
639 struct crush_rule *rule;
640 __u32 step;
641 int i, j;
642 int numrep;
643 int choose_tries = map->choose_total_tries;
644 int choose_local_tries = map->choose_local_tries;
645 int choose_local_fallback_tries = map->choose_local_fallback_tries;
646 int choose_leaf_tries = 0;
647
648 if ((__u32)ruleno >= map->max_rules) {
649 dprintk(" bad ruleno %d\n", ruleno);
650 return 0;
651 }
652
653 rule = map->rules[ruleno];
654 result_len = 0;
655 w = a;
656 o = b;
657
658 for (step = 0; step < rule->len; step++) {
659 int firstn = 0;
660 struct crush_rule_step *curstep = &rule->steps[step];
661
662 switch (curstep->op) {
663 case CRUSH_RULE_TAKE:
664 w[0] = curstep->arg1;
665 wsize = 1;
666 break;
667
668 case CRUSH_RULE_SET_CHOOSE_TRIES:
669 if (curstep->arg1 > 0)
670 choose_tries = curstep->arg1;
671 break;
672
673 case CRUSH_RULE_SET_CHOOSELEAF_TRIES:
674 if (curstep->arg1 > 0)
675 choose_leaf_tries = curstep->arg1;
676 break;
677
678 case CRUSH_RULE_SET_CHOOSE_LOCAL_TRIES:
679 if (curstep->arg1 > 0)
680 choose_local_tries = curstep->arg1;
681 break;
682
683 case CRUSH_RULE_SET_CHOOSE_LOCAL_FALLBACK_TRIES:
684 if (curstep->arg1 > 0)
685 choose_local_fallback_tries = curstep->arg1;
686 break;
687
688 case CRUSH_RULE_CHOOSELEAF_FIRSTN:
689 case CRUSH_RULE_CHOOSE_FIRSTN:
690 firstn = 1;
691 /* fall through */
692 case CRUSH_RULE_CHOOSELEAF_INDEP:
693 case CRUSH_RULE_CHOOSE_INDEP:
694 if (wsize == 0)
695 break;
696
697 recurse_to_leaf =
698 curstep->op ==
699 CRUSH_RULE_CHOOSELEAF_FIRSTN ||
700 curstep->op ==
701 CRUSH_RULE_CHOOSELEAF_INDEP;
702
703 /* reset output */
704 osize = 0;
705
706 for (i = 0; i < wsize; i++) {
707 /*
708 * see CRUSH_N, CRUSH_N_MINUS macros.
709 * basically, numrep <= 0 means relative to
710 * the provided result_max
711 */
712 numrep = curstep->arg1;
713 if (numrep <= 0) {
714 numrep += result_max;
715 if (numrep <= 0)
716 continue;
717 }
718 j = 0;
719 if (firstn) {
720 int recurse_tries;
721 if (choose_leaf_tries)
722 recurse_tries =
723 choose_leaf_tries;
724 else if (map->chooseleaf_descend_once)
725 recurse_tries = 1;
726 else
727 recurse_tries = choose_tries;
728 osize += crush_choose_firstn(
729 map,
730 map->buckets[-1-w[i]],
731 weight, weight_max,
732 x, numrep,
733 curstep->arg2,
734 o+osize, j,
735 choose_tries,
736 recurse_tries,
737 choose_local_tries,
738 choose_local_fallback_tries,
739 recurse_to_leaf,
740 c+osize);
741 } else {
742 crush_choose_indep(
743 map,
744 map->buckets[-1-w[i]],
745 weight, weight_max,
746 x, numrep, numrep,
747 curstep->arg2,
748 o+osize, j,
749 choose_tries,
750 choose_leaf_tries ?
751 choose_leaf_tries : 1,
752 recurse_to_leaf,
753 c+osize,
754 0);
755 osize += numrep;
756 }
757 }
758
759 if (recurse_to_leaf)
760 /* copy final _leaf_ values to output set */
761 memcpy(o, c, osize*sizeof(*o));
762
763 /* swap o and w arrays */
764 tmp = o;
765 o = w;
766 w = tmp;
767 wsize = osize;
768 break;
769
770
771 case CRUSH_RULE_EMIT:
772 for (i = 0; i < wsize && result_len < result_max; i++) {
773 result[result_len] = w[i];
774 result_len++;
775 }
776 wsize = 0;
777 break;
778
779 default:
780 dprintk(" unknown op %d at step %d\n",
781 curstep->op, step);
782 break;
783 }
784 }
785 return result_len;
786 }
787
788
Linux with added FPC-III support