~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/ceph/crush/mapper.c

Version: ~ [ linux-5.13-rc1 ] ~ [ linux-5.12.2 ] ~ [ linux-5.11.19 ] ~ [ linux-5.10.35 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.117 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.190 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.232 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.268 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.268 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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  */
 12 
 13 #ifdef __KERNEL__
 14 # include <linux/string.h>
 15 # include <linux/slab.h>
 16 # include <linux/bug.h>
 17 # include <linux/kernel.h>
 18 # include <linux/crush/crush.h>
 19 # include <linux/crush/hash.h>
 20 #else
 21 # include "crush_compat.h"
 22 # include "crush.h"
 23 # include "hash.h"
 24 #endif
 25 #include "crush_ln_table.h"
 26 
 27 #define dprintk(args...) /* printf(args) */
 28 
 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  */
 40 int crush_find_rule(const struct crush_map *map, int ruleset, int type, int size)
 41 {
 42         __u32 i;
 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 {
 76         unsigned int pr = r % bucket->size;
 77         unsigned int i, s;
 78 
 79         /* start a new permutation if @x has changed */
 80         if (bucket->perm_x != (__u32)x || bucket->perm_n == 0) {
 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) {
 86                         s = crush_hash32_3(bucket->hash, x, bucket->id, 0) %
 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) {
108                 unsigned int p = bucket->perm_n;
109                 /* no point in swapping the final entry */
110                 if (p < bucket->size - 1) {
111                         i = crush_hash32_3(bucket->hash, x, bucket->id, p) %
112                                 (bucket->size - p);
113                         if (i) {
114                                 unsigned int t = bucket->perm[p + i];
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--) {
146                 __u64 w = crush_hash32_4(bucket->h.hash, x, bucket->h.items[i],
147                                          r, bucket->h.id);
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 
160         dprintk("bad list sums for bucket %d\n", bucket->h.id);
161         return bucket->h.items[0];
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 {
196         int n;
197         __u32 w;
198         __u64 t;
199 
200         /* start at root */
201         n = bucket->num_nodes >> 1;
202 
203         while (!terminal(n)) {
204                 int l;
205                 /* pick point in [0, w) */
206                 w = bucket->node_weights[n];
207                 t = (__u64)crush_hash32_4(bucket->h.hash, x, n, r,
208                                           bucket->h.id) * (__u64)w;
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 {
228         __u32 i;
229         int high = 0;
230         __u64 high_draw = 0;
231         __u64 draw;
232 
233         for (i = 0; i < bucket->h.size; i++) {
234                 draw = crush_hash32_3(bucket->h.hash, x, bucket->h.items[i], r);
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 
245 /* compute 2^44*log2(input+1) */
246 static __u64 crush_ln(unsigned int xin)
247 {
248         unsigned int x = xin, x1;
249         int iexpon, index1, index2;
250         __u64 RH, LH, LL, xl64, result;
251 
252         x++;
253 
254         /* normalize input */
255         iexpon = 15;
256         while (!(x & 0x18000)) {
257                 x <<= 1;
258                 iexpon--;
259         }
260 
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];
266 
267         /* RH*x ~ 2^48 * (2^15 + xf), xf<2^8 */
268         xl64 = (__s64)x * RH;
269         xl64 >>= 48;
270         x1 = xl64;
271 
272         result = iexpon;
273         result <<= (12 + 32);
274 
275         index2 = x1 & 0xff;
276         /* LL ~ 2^48*log2(1.0+index2/2^15) */
277         LL = __LL_tbl[index2];
278 
279         LH = LH + LL;
280 
281         LH >>= (48 - 12 - 32);
282         result += LH;
283 
284         return result;
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 {
300         unsigned int i, high = 0;
301         unsigned int u;
302         unsigned int w;
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 
344 static int crush_bucket_choose(struct crush_bucket *in, int x, int r)
345 {
346         dprintk(" crush_bucket_choose %d x=%d r=%d\n", in->id, x, r);
347         BUG_ON(in->size == 0);
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);
361         case CRUSH_BUCKET_STRAW2:
362                 return bucket_straw2_choose((struct crush_bucket_straw2 *)in,
363                                             x, r);
364         default:
365                 dprintk("unknown bucket %d alg %d\n", in->id, in->alg);
366                 return in->items[0];
367         }
368 }
369 
370 
371 /*
372  * true if device is marked "out" (failed, fully offloaded)
373  * of the cluster
374  */
375 static int is_out(const struct crush_map *map,
376                   const __u32 *weight, int weight_max,
377                   int item, int x)
378 {
379         if (item >= weight_max)
380                 return 1;
381         if (weight[item] >= 0x10000)
382                 return 0;
383         if (weight[item] == 0)
384                 return 1;
385         if ((crush_hash32_2(CRUSH_HASH_RJENKINS1, x, item) & 0xffff)
386             < weight[item])
387                 return 0;
388         return 1;
389 }
390 
391 /**
392  * crush_choose_firstn - choose numrep distinct items of given type
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
400  * @out_size: size of the out vector
401  * @tries: number of attempts to make
402  * @recurse_tries: number of attempts to have recursive chooseleaf make
403  * @local_retries: localized retries
404  * @local_fallback_retries: localized fallback retries
405  * @recurse_to_leaf: true if we want one device under each item of given type (chooseleaf instead of choose)
406  * @stable: stable mode starts rep=0 in the recursive call for all replicas
407  * @vary_r: pass r to recursive calls
408  * @out2: second output vector for leaf items (if @recurse_to_leaf)
409  * @parent_r: r value passed from the parent
410  */
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,
416                                int out_size,
417                                unsigned int tries,
418                                unsigned int recurse_tries,
419                                unsigned int local_retries,
420                                unsigned int local_fallback_retries,
421                                int recurse_to_leaf,
422                                unsigned int vary_r,
423                                unsigned int stable,
424                                int *out2,
425                                int parent_r)
426 {
427         int rep;
428         unsigned int ftotal, flocal;
429         int retry_descent, retry_bucket, skip_rep;
430         struct crush_bucket *in = bucket;
431         int r;
432         int i;
433         int item = 0;
434         int itemtype;
435         int collide, reject;
436         int count = out_size;
437 
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",
439                 recurse_to_leaf ? "_LEAF" : "",
440                 bucket->id, x, outpos, numrep,
441                 tries, recurse_tries, local_retries, local_fallback_retries,
442                 parent_r, stable);
443 
444         for (rep = stable ? 0 : outpos; rep < numrep && count > 0 ; rep++) {
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 {
455                                 collide = 0;
456                                 retry_bucket = 0;
457                                 r = rep + parent_r;
458                                 /* r' = r + f_total */
459                                 r += ftotal;
460 
461                                 /* bucket choose */
462                                 if (in->size == 0) {
463                                         reject = 1;
464                                         goto reject;
465                                 }
466                                 if (local_fallback_retries > 0 &&
467                                     flocal >= (in->size>>1) &&
468                                     flocal > local_fallback_retries)
469                                         item = bucket_perm_choose(in, x, r);
470                                 else
471                                         item = crush_bucket_choose(in, x, r);
472                                 if (item >= map->max_devices) {
473                                         dprintk("   bad item %d\n", item);
474                                         skip_rep = 1;
475                                         break;
476                                 }
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) {
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                                         }
493                                         in = map->buckets[-1-item];
494                                         retry_bucket = 1;
495                                         continue;
496                                 }
497 
498                                 /* collision? */
499                                 for (i = 0; i < outpos; i++) {
500                                         if (out[i] == item) {
501                                                 collide = 1;
502                                                 break;
503                                         }
504                                 }
505 
506                                 reject = 0;
507                                 if (!collide && recurse_to_leaf) {
508                                         if (item < 0) {
509                                                 int sub_r;
510                                                 if (vary_r)
511                                                         sub_r = r >> (vary_r-1);
512                                                 else
513                                                         sub_r = 0;
514                                                 if (crush_choose_firstn(map,
515                                                          map->buckets[-1-item],
516                                                          weight, weight_max,
517                                                          x, stable ? 1 : outpos+1, 0,
518                                                          out2, outpos, count,
519                                                          recurse_tries, 0,
520                                                          local_retries,
521                                                          local_fallback_retries,
522                                                          0,
523                                                          vary_r,
524                                                          stable,
525                                                          NULL,
526                                                          sub_r) <= outpos)
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) {
536                                         /* out? */
537                                         if (itemtype == 0)
538                                                 reject = is_out(map, weight,
539                                                                 weight_max,
540                                                                 item, x);
541                                         else
542                                                 reject = 0;
543                                 }
544 
545 reject:
546                                 if (reject || collide) {
547                                         ftotal++;
548                                         flocal++;
549 
550                                         if (collide && flocal <= local_retries)
551                                                 /* retry locally a few times */
552                                                 retry_bucket = 1;
553                                         else if (local_fallback_retries > 0 &&
554                                                  flocal <= in->size + local_fallback_retries)
555                                                 /* exhaustive bucket search */
556                                                 retry_bucket = 1;
557                                         else if (ftotal < tries)
558                                                 /* then retry descent */
559                                                 retry_descent = 1;
560                                         else
561                                                 /* else give up */
562                                                 skip_rep = 1;
563                                         dprintk("  reject %d  collide %d  "
564                                                 "ftotal %u  flocal %u\n",
565                                                 reject, collide, ftotal,
566                                                 flocal);
567                                 }
568                         } while (retry_bucket);
569                 } while (retry_descent);
570 
571                 if (skip_rep) {
572                         dprintk("skip rep\n");
573                         continue;
574                 }
575 
576                 dprintk("CHOOSE got %d\n", item);
577                 out[outpos] = item;
578                 outpos++;
579                 count--;
580 #ifndef __KERNEL__
581                 if (map->choose_tries && ftotal <= map->choose_total_tries)
582                         map->choose_tries[ftotal]++;
583 #endif
584         }
585 
586         dprintk("CHOOSE returns %d\n", outpos);
587         return outpos;
588 }
589 
590 
591 /**
592  * crush_choose_indep: alternative breadth-first positionally stable mapping
593  *
594  */
595 static void crush_choose_indep(const struct crush_map *map,
596                                struct crush_bucket *bucket,
597                                const __u32 *weight, int weight_max,
598                                int x, int left, int numrep, int type,
599                                int *out, int outpos,
600                                unsigned int tries,
601                                unsigned int recurse_tries,
602                                int recurse_to_leaf,
603                                int *out2,
604                                int parent_r)
605 {
606         struct crush_bucket *in = bucket;
607         int endpos = outpos + left;
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 */
620         for (rep = outpos; rep < endpos; rep++) {
621                 out[rep] = CRUSH_ITEM_UNDEF;
622                 if (out2)
623                         out2[rep] = CRUSH_ITEM_UNDEF;
624         }
625 
626         for (ftotal = 0; left > 0 && ftotal < tries; ftotal++) {
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
641                 for (rep = outpos; rep < endpos; rep++) {
642                         if (out[rep] != CRUSH_ITEM_UNDEF)
643                                 continue;
644 
645                         in = bucket;  /* initial bucket */
646 
647                         /* choose through intervening buckets */
648                         for (;;) {
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                                  */
657                                 r = rep + parent_r;
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;
709                                 for (i = outpos; i < endpos; i++) {
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,
721                                                    map->buckets[-1-item],
722                                                    weight, weight_max,
723                                                    x, 1, numrep, 0,
724                                                    out2, rep,
725                                                    recurse_tries, 0,
726                                                    0, NULL, r);
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         }
749         for (rep = outpos; rep < endpos; rep++) {
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         }
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
775 }
776 
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
784  * @weight: weight vector (for map leaves)
785  * @weight_max: size of weight vector
786  * @scratch: scratch vector for private use; must be >= 3 * result_max
787  */
788 int crush_do_rule(const struct crush_map *map,
789                   int ruleno, int x, int *result, int result_max,
790                   const __u32 *weight, int weight_max,
791                   int *scratch)
792 {
793         int result_len;
794         int *a = scratch;
795         int *b = scratch + result_max;
796         int *c = scratch + result_max*2;
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;
804         __u32 step;
805         int i, j;
806         int numrep;
807         int out_size;
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;
813         int choose_leaf_tries = 0;
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;
820 
821         int vary_r = map->chooseleaf_vary_r;
822         int stable = map->chooseleaf_stable;
823 
824         if ((__u32)ruleno >= map->max_rules) {
825                 dprintk(" bad ruleno %d\n", ruleno);
826                 return 0;
827         }
828 
829         rule = map->rules[ruleno];
830         result_len = 0;
831         w = a;
832         o = b;
833 
834         for (step = 0; step < rule->len; step++) {
835                 int firstn = 0;
836                 struct crush_rule_step *curstep = &rule->steps[step];
837 
838                 switch (curstep->op) {
839                 case CRUSH_RULE_TAKE:
840                         if ((curstep->arg1 >= 0 &&
841                              curstep->arg1 < map->max_devices) ||
842                             (-1-curstep->arg1 >= 0 &&
843                              -1-curstep->arg1 < map->max_buckets &&
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                         }
850                         break;
851 
852                 case CRUSH_RULE_SET_CHOOSE_TRIES:
853                         if (curstep->arg1 > 0)
854                                 choose_tries = curstep->arg1;
855                         break;
856 
857                 case CRUSH_RULE_SET_CHOOSELEAF_TRIES:
858                         if (curstep->arg1 > 0)
859                                 choose_leaf_tries = curstep->arg1;
860                         break;
861 
862                 case CRUSH_RULE_SET_CHOOSE_LOCAL_TRIES:
863                         if (curstep->arg1 >= 0)
864                                 choose_local_retries = curstep->arg1;
865                         break;
866 
867                 case CRUSH_RULE_SET_CHOOSE_LOCAL_FALLBACK_TRIES:
868                         if (curstep->arg1 >= 0)
869                                 choose_local_fallback_retries = curstep->arg1;
870                         break;
871 
872                 case CRUSH_RULE_SET_CHOOSELEAF_VARY_R:
873                         if (curstep->arg1 >= 0)
874                                 vary_r = curstep->arg1;
875                         break;
876 
877                 case CRUSH_RULE_SET_CHOOSELEAF_STABLE:
878                         if (curstep->arg1 >= 0)
879                                 stable = curstep->arg1;
880                         break;
881 
882                 case CRUSH_RULE_CHOOSELEAF_FIRSTN:
883                 case CRUSH_RULE_CHOOSE_FIRSTN:
884                         firstn = 1;
885                         /* fall through */
886                 case CRUSH_RULE_CHOOSELEAF_INDEP:
887                 case CRUSH_RULE_CHOOSE_INDEP:
888                         if (wsize == 0)
889                                 break;
890 
891                         recurse_to_leaf =
892                                 curstep->op ==
893                                  CRUSH_RULE_CHOOSELEAF_FIRSTN ||
894                                 curstep->op ==
895                                 CRUSH_RULE_CHOOSELEAF_INDEP;
896 
897                         /* reset output */
898                         osize = 0;
899 
900                         for (i = 0; i < wsize; i++) {
901                                 int bno;
902                                 /*
903                                  * see CRUSH_N, CRUSH_N_MINUS macros.
904                                  * basically, numrep <= 0 means relative to
905                                  * the provided result_max
906                                  */
907                                 numrep = curstep->arg1;
908                                 if (numrep <= 0) {
909                                         numrep += result_max;
910                                         if (numrep <= 0)
911                                                 continue;
912                                 }
913                                 j = 0;
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                                 }
921                                 if (firstn) {
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;
930                                         osize += crush_choose_firstn(
931                                                 map,
932                                                 map->buckets[bno],
933                                                 weight, weight_max,
934                                                 x, numrep,
935                                                 curstep->arg2,
936                                                 o+osize, j,
937                                                 result_max-osize,
938                                                 choose_tries,
939                                                 recurse_tries,
940                                                 choose_local_retries,
941                                                 choose_local_fallback_retries,
942                                                 recurse_to_leaf,
943                                                 vary_r,
944                                                 stable,
945                                                 c+osize,
946                                                 0);
947                                 } else {
948                                         out_size = ((numrep < (result_max-osize)) ?
949                                                     numrep : (result_max-osize));
950                                         crush_choose_indep(
951                                                 map,
952                                                 map->buckets[bno],
953                                                 weight, weight_max,
954                                                 x, out_size, numrep,
955                                                 curstep->arg2,
956                                                 o+osize, j,
957                                                 choose_tries,
958                                                 choose_leaf_tries ?
959                                                    choose_leaf_tries : 1,
960                                                 recurse_to_leaf,
961                                                 c+osize,
962                                                 0);
963                                         osize += out_size;
964                                 }
965                         }
966 
967                         if (recurse_to_leaf)
968                                 /* copy final _leaf_ values to output set */
969                                 memcpy(o, c, osize*sizeof(*o));
970 
971                         /* swap o and w arrays */
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:
988                         dprintk(" unknown op %d at step %d\n",
989                                 curstep->op, step);
990                         break;
991                 }
992         }
993         return result_len;
994 }
995 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp