Commit | Line | Data |
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66a63635 JT |
1 | /* |
2 | * Copyright (C) 2015 Red Hat. All rights reserved. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | ||
b29d4986 | 7 | #include "dm-cache-background-tracker.h" |
66a63635 | 8 | #include "dm-cache-policy-internal.h" |
b29d4986 | 9 | #include "dm-cache-policy.h" |
66a63635 JT |
10 | #include "dm.h" |
11 | ||
12 | #include <linux/hash.h> | |
13 | #include <linux/jiffies.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/mutex.h> | |
16 | #include <linux/vmalloc.h> | |
17 | #include <linux/math64.h> | |
18 | ||
19 | #define DM_MSG_PREFIX "cache-policy-smq" | |
20 | ||
21 | /*----------------------------------------------------------------*/ | |
22 | ||
23 | /* | |
24 | * Safe division functions that return zero on divide by zero. | |
25 | */ | |
26 | static unsigned safe_div(unsigned n, unsigned d) | |
27 | { | |
28 | return d ? n / d : 0u; | |
29 | } | |
30 | ||
31 | static unsigned safe_mod(unsigned n, unsigned d) | |
32 | { | |
33 | return d ? n % d : 0u; | |
34 | } | |
35 | ||
36 | /*----------------------------------------------------------------*/ | |
37 | ||
38 | struct entry { | |
39 | unsigned hash_next:28; | |
40 | unsigned prev:28; | |
41 | unsigned next:28; | |
b29d4986 | 42 | unsigned level:6; |
66a63635 JT |
43 | bool dirty:1; |
44 | bool allocated:1; | |
45 | bool sentinel:1; | |
b29d4986 | 46 | bool pending_work:1; |
66a63635 JT |
47 | |
48 | dm_oblock_t oblock; | |
49 | }; | |
50 | ||
51 | /*----------------------------------------------------------------*/ | |
52 | ||
53 | #define INDEXER_NULL ((1u << 28u) - 1u) | |
54 | ||
55 | /* | |
56 | * An entry_space manages a set of entries that we use for the queues. | |
57 | * The clean and dirty queues share entries, so this object is separate | |
58 | * from the queue itself. | |
59 | */ | |
60 | struct entry_space { | |
61 | struct entry *begin; | |
62 | struct entry *end; | |
63 | }; | |
64 | ||
65 | static int space_init(struct entry_space *es, unsigned nr_entries) | |
66 | { | |
67 | if (!nr_entries) { | |
68 | es->begin = es->end = NULL; | |
69 | return 0; | |
70 | } | |
71 | ||
fad953ce | 72 | es->begin = vzalloc(array_size(nr_entries, sizeof(struct entry))); |
66a63635 JT |
73 | if (!es->begin) |
74 | return -ENOMEM; | |
75 | ||
76 | es->end = es->begin + nr_entries; | |
77 | return 0; | |
78 | } | |
79 | ||
80 | static void space_exit(struct entry_space *es) | |
81 | { | |
82 | vfree(es->begin); | |
83 | } | |
84 | ||
85 | static struct entry *__get_entry(struct entry_space *es, unsigned block) | |
86 | { | |
87 | struct entry *e; | |
88 | ||
89 | e = es->begin + block; | |
90 | BUG_ON(e >= es->end); | |
91 | ||
92 | return e; | |
93 | } | |
94 | ||
95 | static unsigned to_index(struct entry_space *es, struct entry *e) | |
96 | { | |
97 | BUG_ON(e < es->begin || e >= es->end); | |
98 | return e - es->begin; | |
99 | } | |
100 | ||
101 | static struct entry *to_entry(struct entry_space *es, unsigned block) | |
102 | { | |
103 | if (block == INDEXER_NULL) | |
104 | return NULL; | |
105 | ||
106 | return __get_entry(es, block); | |
107 | } | |
108 | ||
109 | /*----------------------------------------------------------------*/ | |
110 | ||
111 | struct ilist { | |
112 | unsigned nr_elts; /* excluding sentinel entries */ | |
113 | unsigned head, tail; | |
114 | }; | |
115 | ||
116 | static void l_init(struct ilist *l) | |
117 | { | |
118 | l->nr_elts = 0; | |
119 | l->head = l->tail = INDEXER_NULL; | |
120 | } | |
121 | ||
122 | static struct entry *l_head(struct entry_space *es, struct ilist *l) | |
123 | { | |
124 | return to_entry(es, l->head); | |
125 | } | |
126 | ||
127 | static struct entry *l_tail(struct entry_space *es, struct ilist *l) | |
128 | { | |
129 | return to_entry(es, l->tail); | |
130 | } | |
131 | ||
132 | static struct entry *l_next(struct entry_space *es, struct entry *e) | |
133 | { | |
134 | return to_entry(es, e->next); | |
135 | } | |
136 | ||
137 | static struct entry *l_prev(struct entry_space *es, struct entry *e) | |
138 | { | |
139 | return to_entry(es, e->prev); | |
140 | } | |
141 | ||
142 | static bool l_empty(struct ilist *l) | |
143 | { | |
144 | return l->head == INDEXER_NULL; | |
145 | } | |
146 | ||
147 | static void l_add_head(struct entry_space *es, struct ilist *l, struct entry *e) | |
148 | { | |
149 | struct entry *head = l_head(es, l); | |
150 | ||
151 | e->next = l->head; | |
152 | e->prev = INDEXER_NULL; | |
153 | ||
154 | if (head) | |
155 | head->prev = l->head = to_index(es, e); | |
156 | else | |
157 | l->head = l->tail = to_index(es, e); | |
158 | ||
159 | if (!e->sentinel) | |
160 | l->nr_elts++; | |
161 | } | |
162 | ||
163 | static void l_add_tail(struct entry_space *es, struct ilist *l, struct entry *e) | |
164 | { | |
165 | struct entry *tail = l_tail(es, l); | |
166 | ||
167 | e->next = INDEXER_NULL; | |
168 | e->prev = l->tail; | |
169 | ||
170 | if (tail) | |
171 | tail->next = l->tail = to_index(es, e); | |
172 | else | |
173 | l->head = l->tail = to_index(es, e); | |
174 | ||
175 | if (!e->sentinel) | |
176 | l->nr_elts++; | |
177 | } | |
178 | ||
179 | static void l_add_before(struct entry_space *es, struct ilist *l, | |
180 | struct entry *old, struct entry *e) | |
181 | { | |
182 | struct entry *prev = l_prev(es, old); | |
183 | ||
184 | if (!prev) | |
185 | l_add_head(es, l, e); | |
186 | ||
187 | else { | |
188 | e->prev = old->prev; | |
189 | e->next = to_index(es, old); | |
190 | prev->next = old->prev = to_index(es, e); | |
191 | ||
192 | if (!e->sentinel) | |
193 | l->nr_elts++; | |
194 | } | |
195 | } | |
196 | ||
197 | static void l_del(struct entry_space *es, struct ilist *l, struct entry *e) | |
198 | { | |
199 | struct entry *prev = l_prev(es, e); | |
200 | struct entry *next = l_next(es, e); | |
201 | ||
202 | if (prev) | |
203 | prev->next = e->next; | |
204 | else | |
205 | l->head = e->next; | |
206 | ||
207 | if (next) | |
208 | next->prev = e->prev; | |
209 | else | |
210 | l->tail = e->prev; | |
211 | ||
212 | if (!e->sentinel) | |
213 | l->nr_elts--; | |
214 | } | |
215 | ||
9768a10d JT |
216 | static struct entry *l_pop_head(struct entry_space *es, struct ilist *l) |
217 | { | |
218 | struct entry *e; | |
219 | ||
220 | for (e = l_head(es, l); e; e = l_next(es, e)) | |
221 | if (!e->sentinel) { | |
222 | l_del(es, l, e); | |
223 | return e; | |
224 | } | |
225 | ||
226 | return NULL; | |
227 | } | |
228 | ||
66a63635 JT |
229 | static struct entry *l_pop_tail(struct entry_space *es, struct ilist *l) |
230 | { | |
231 | struct entry *e; | |
232 | ||
233 | for (e = l_tail(es, l); e; e = l_prev(es, e)) | |
234 | if (!e->sentinel) { | |
235 | l_del(es, l, e); | |
236 | return e; | |
237 | } | |
238 | ||
239 | return NULL; | |
240 | } | |
241 | ||
242 | /*----------------------------------------------------------------*/ | |
243 | ||
244 | /* | |
245 | * The stochastic-multi-queue is a set of lru lists stacked into levels. | |
246 | * Entries are moved up levels when they are used, which loosely orders the | |
247 | * most accessed entries in the top levels and least in the bottom. This | |
248 | * structure is *much* better than a single lru list. | |
249 | */ | |
250 | #define MAX_LEVELS 64u | |
251 | ||
252 | struct queue { | |
253 | struct entry_space *es; | |
254 | ||
255 | unsigned nr_elts; | |
256 | unsigned nr_levels; | |
257 | struct ilist qs[MAX_LEVELS]; | |
258 | ||
259 | /* | |
260 | * We maintain a count of the number of entries we would like in each | |
261 | * level. | |
262 | */ | |
263 | unsigned last_target_nr_elts; | |
264 | unsigned nr_top_levels; | |
265 | unsigned nr_in_top_levels; | |
266 | unsigned target_count[MAX_LEVELS]; | |
267 | }; | |
268 | ||
269 | static void q_init(struct queue *q, struct entry_space *es, unsigned nr_levels) | |
270 | { | |
271 | unsigned i; | |
272 | ||
273 | q->es = es; | |
274 | q->nr_elts = 0; | |
275 | q->nr_levels = nr_levels; | |
276 | ||
277 | for (i = 0; i < q->nr_levels; i++) { | |
278 | l_init(q->qs + i); | |
279 | q->target_count[i] = 0u; | |
280 | } | |
281 | ||
282 | q->last_target_nr_elts = 0u; | |
283 | q->nr_top_levels = 0u; | |
284 | q->nr_in_top_levels = 0u; | |
285 | } | |
286 | ||
287 | static unsigned q_size(struct queue *q) | |
288 | { | |
289 | return q->nr_elts; | |
290 | } | |
291 | ||
292 | /* | |
293 | * Insert an entry to the back of the given level. | |
294 | */ | |
295 | static void q_push(struct queue *q, struct entry *e) | |
296 | { | |
b29d4986 JT |
297 | BUG_ON(e->pending_work); |
298 | ||
66a63635 JT |
299 | if (!e->sentinel) |
300 | q->nr_elts++; | |
301 | ||
302 | l_add_tail(q->es, q->qs + e->level, e); | |
303 | } | |
304 | ||
b29d4986 JT |
305 | static void q_push_front(struct queue *q, struct entry *e) |
306 | { | |
307 | BUG_ON(e->pending_work); | |
308 | ||
309 | if (!e->sentinel) | |
310 | q->nr_elts++; | |
311 | ||
312 | l_add_head(q->es, q->qs + e->level, e); | |
313 | } | |
314 | ||
66a63635 JT |
315 | static void q_push_before(struct queue *q, struct entry *old, struct entry *e) |
316 | { | |
b29d4986 JT |
317 | BUG_ON(e->pending_work); |
318 | ||
66a63635 JT |
319 | if (!e->sentinel) |
320 | q->nr_elts++; | |
321 | ||
322 | l_add_before(q->es, q->qs + e->level, old, e); | |
323 | } | |
324 | ||
325 | static void q_del(struct queue *q, struct entry *e) | |
326 | { | |
327 | l_del(q->es, q->qs + e->level, e); | |
328 | if (!e->sentinel) | |
329 | q->nr_elts--; | |
330 | } | |
331 | ||
332 | /* | |
333 | * Return the oldest entry of the lowest populated level. | |
334 | */ | |
335 | static struct entry *q_peek(struct queue *q, unsigned max_level, bool can_cross_sentinel) | |
336 | { | |
337 | unsigned level; | |
338 | struct entry *e; | |
339 | ||
340 | max_level = min(max_level, q->nr_levels); | |
341 | ||
342 | for (level = 0; level < max_level; level++) | |
343 | for (e = l_head(q->es, q->qs + level); e; e = l_next(q->es, e)) { | |
344 | if (e->sentinel) { | |
345 | if (can_cross_sentinel) | |
346 | continue; | |
347 | else | |
348 | break; | |
349 | } | |
350 | ||
351 | return e; | |
352 | } | |
353 | ||
354 | return NULL; | |
355 | } | |
356 | ||
357 | static struct entry *q_pop(struct queue *q) | |
358 | { | |
359 | struct entry *e = q_peek(q, q->nr_levels, true); | |
360 | ||
361 | if (e) | |
362 | q_del(q, e); | |
363 | ||
364 | return e; | |
365 | } | |
366 | ||
66a63635 JT |
367 | /* |
368 | * This function assumes there is a non-sentinel entry to pop. It's only | |
369 | * used by redistribute, so we know this is true. It also doesn't adjust | |
370 | * the q->nr_elts count. | |
371 | */ | |
372 | static struct entry *__redist_pop_from(struct queue *q, unsigned level) | |
373 | { | |
374 | struct entry *e; | |
375 | ||
376 | for (; level < q->nr_levels; level++) | |
377 | for (e = l_head(q->es, q->qs + level); e; e = l_next(q->es, e)) | |
378 | if (!e->sentinel) { | |
379 | l_del(q->es, q->qs + e->level, e); | |
380 | return e; | |
381 | } | |
382 | ||
383 | return NULL; | |
384 | } | |
385 | ||
386 | static void q_set_targets_subrange_(struct queue *q, unsigned nr_elts, unsigned lbegin, unsigned lend) | |
387 | { | |
388 | unsigned level, nr_levels, entries_per_level, remainder; | |
389 | ||
390 | BUG_ON(lbegin > lend); | |
391 | BUG_ON(lend > q->nr_levels); | |
392 | nr_levels = lend - lbegin; | |
393 | entries_per_level = safe_div(nr_elts, nr_levels); | |
394 | remainder = safe_mod(nr_elts, nr_levels); | |
395 | ||
396 | for (level = lbegin; level < lend; level++) | |
397 | q->target_count[level] = | |
398 | (level < (lbegin + remainder)) ? entries_per_level + 1u : entries_per_level; | |
399 | } | |
400 | ||
401 | /* | |
402 | * Typically we have fewer elements in the top few levels which allows us | |
403 | * to adjust the promote threshold nicely. | |
404 | */ | |
405 | static void q_set_targets(struct queue *q) | |
406 | { | |
407 | if (q->last_target_nr_elts == q->nr_elts) | |
408 | return; | |
409 | ||
410 | q->last_target_nr_elts = q->nr_elts; | |
411 | ||
412 | if (q->nr_top_levels > q->nr_levels) | |
413 | q_set_targets_subrange_(q, q->nr_elts, 0, q->nr_levels); | |
414 | ||
415 | else { | |
416 | q_set_targets_subrange_(q, q->nr_in_top_levels, | |
417 | q->nr_levels - q->nr_top_levels, q->nr_levels); | |
418 | ||
419 | if (q->nr_in_top_levels < q->nr_elts) | |
420 | q_set_targets_subrange_(q, q->nr_elts - q->nr_in_top_levels, | |
421 | 0, q->nr_levels - q->nr_top_levels); | |
422 | else | |
423 | q_set_targets_subrange_(q, 0, 0, q->nr_levels - q->nr_top_levels); | |
424 | } | |
425 | } | |
426 | ||
427 | static void q_redistribute(struct queue *q) | |
428 | { | |
429 | unsigned target, level; | |
430 | struct ilist *l, *l_above; | |
431 | struct entry *e; | |
432 | ||
433 | q_set_targets(q); | |
434 | ||
435 | for (level = 0u; level < q->nr_levels - 1u; level++) { | |
436 | l = q->qs + level; | |
437 | target = q->target_count[level]; | |
438 | ||
439 | /* | |
440 | * Pull down some entries from the level above. | |
441 | */ | |
442 | while (l->nr_elts < target) { | |
443 | e = __redist_pop_from(q, level + 1u); | |
444 | if (!e) { | |
445 | /* bug in nr_elts */ | |
446 | break; | |
447 | } | |
448 | ||
449 | e->level = level; | |
450 | l_add_tail(q->es, l, e); | |
451 | } | |
452 | ||
453 | /* | |
454 | * Push some entries up. | |
455 | */ | |
456 | l_above = q->qs + level + 1u; | |
457 | while (l->nr_elts > target) { | |
458 | e = l_pop_tail(q->es, l); | |
459 | ||
460 | if (!e) | |
461 | /* bug in nr_elts */ | |
462 | break; | |
463 | ||
464 | e->level = level + 1u; | |
b29d4986 | 465 | l_add_tail(q->es, l_above, e); |
66a63635 JT |
466 | } |
467 | } | |
468 | } | |
469 | ||
b29d4986 JT |
470 | static void q_requeue(struct queue *q, struct entry *e, unsigned extra_levels, |
471 | struct entry *s1, struct entry *s2) | |
66a63635 JT |
472 | { |
473 | struct entry *de; | |
b29d4986 JT |
474 | unsigned sentinels_passed = 0; |
475 | unsigned new_level = min(q->nr_levels - 1u, e->level + extra_levels); | |
66a63635 | 476 | |
b29d4986 | 477 | /* try and find an entry to swap with */ |
66a63635 | 478 | if (extra_levels && (e->level < q->nr_levels - 1u)) { |
b29d4986 JT |
479 | for (de = l_head(q->es, q->qs + new_level); de && de->sentinel; de = l_next(q->es, de)) |
480 | sentinels_passed++; | |
66a63635 | 481 | |
b29d4986 | 482 | if (de) { |
66a63635 JT |
483 | q_del(q, de); |
484 | de->level = e->level; | |
b29d4986 JT |
485 | if (s1) { |
486 | switch (sentinels_passed) { | |
487 | case 0: | |
488 | q_push_before(q, s1, de); | |
489 | break; | |
490 | ||
491 | case 1: | |
492 | q_push_before(q, s2, de); | |
493 | break; | |
66a63635 | 494 | |
b29d4986 JT |
495 | default: |
496 | q_push(q, de); | |
497 | } | |
498 | } else | |
66a63635 | 499 | q_push(q, de); |
66a63635 | 500 | } |
66a63635 JT |
501 | } |
502 | ||
b29d4986 JT |
503 | q_del(q, e); |
504 | e->level = new_level; | |
66a63635 JT |
505 | q_push(q, e); |
506 | } | |
507 | ||
66a63635 JT |
508 | /*----------------------------------------------------------------*/ |
509 | ||
510 | #define FP_SHIFT 8 | |
511 | #define SIXTEENTH (1u << (FP_SHIFT - 4u)) | |
512 | #define EIGHTH (1u << (FP_SHIFT - 3u)) | |
513 | ||
514 | struct stats { | |
515 | unsigned hit_threshold; | |
516 | unsigned hits; | |
517 | unsigned misses; | |
518 | }; | |
519 | ||
520 | enum performance { | |
521 | Q_POOR, | |
522 | Q_FAIR, | |
523 | Q_WELL | |
524 | }; | |
525 | ||
526 | static void stats_init(struct stats *s, unsigned nr_levels) | |
527 | { | |
528 | s->hit_threshold = (nr_levels * 3u) / 4u; | |
529 | s->hits = 0u; | |
530 | s->misses = 0u; | |
531 | } | |
532 | ||
533 | static void stats_reset(struct stats *s) | |
534 | { | |
535 | s->hits = s->misses = 0u; | |
536 | } | |
537 | ||
538 | static void stats_level_accessed(struct stats *s, unsigned level) | |
539 | { | |
540 | if (level >= s->hit_threshold) | |
541 | s->hits++; | |
542 | else | |
543 | s->misses++; | |
544 | } | |
545 | ||
546 | static void stats_miss(struct stats *s) | |
547 | { | |
548 | s->misses++; | |
549 | } | |
550 | ||
551 | /* | |
552 | * There are times when we don't have any confidence in the hotspot queue. | |
553 | * Such as when a fresh cache is created and the blocks have been spread | |
554 | * out across the levels, or if an io load changes. We detect this by | |
555 | * seeing how often a lookup is in the top levels of the hotspot queue. | |
556 | */ | |
557 | static enum performance stats_assess(struct stats *s) | |
558 | { | |
559 | unsigned confidence = safe_div(s->hits << FP_SHIFT, s->hits + s->misses); | |
560 | ||
561 | if (confidence < SIXTEENTH) | |
562 | return Q_POOR; | |
563 | ||
564 | else if (confidence < EIGHTH) | |
565 | return Q_FAIR; | |
566 | ||
567 | else | |
568 | return Q_WELL; | |
569 | } | |
570 | ||
571 | /*----------------------------------------------------------------*/ | |
572 | ||
b29d4986 | 573 | struct smq_hash_table { |
66a63635 JT |
574 | struct entry_space *es; |
575 | unsigned long long hash_bits; | |
576 | unsigned *buckets; | |
577 | }; | |
578 | ||
579 | /* | |
580 | * All cache entries are stored in a chained hash table. To save space we | |
581 | * use indexing again, and only store indexes to the next entry. | |
582 | */ | |
b29d4986 | 583 | static int h_init(struct smq_hash_table *ht, struct entry_space *es, unsigned nr_entries) |
66a63635 JT |
584 | { |
585 | unsigned i, nr_buckets; | |
586 | ||
587 | ht->es = es; | |
588 | nr_buckets = roundup_pow_of_two(max(nr_entries / 4u, 16u)); | |
a3d939ae | 589 | ht->hash_bits = __ffs(nr_buckets); |
66a63635 | 590 | |
42bc47b3 | 591 | ht->buckets = vmalloc(array_size(nr_buckets, sizeof(*ht->buckets))); |
66a63635 JT |
592 | if (!ht->buckets) |
593 | return -ENOMEM; | |
594 | ||
595 | for (i = 0; i < nr_buckets; i++) | |
596 | ht->buckets[i] = INDEXER_NULL; | |
597 | ||
598 | return 0; | |
599 | } | |
600 | ||
b29d4986 | 601 | static void h_exit(struct smq_hash_table *ht) |
66a63635 JT |
602 | { |
603 | vfree(ht->buckets); | |
604 | } | |
605 | ||
b29d4986 | 606 | static struct entry *h_head(struct smq_hash_table *ht, unsigned bucket) |
66a63635 JT |
607 | { |
608 | return to_entry(ht->es, ht->buckets[bucket]); | |
609 | } | |
610 | ||
b29d4986 | 611 | static struct entry *h_next(struct smq_hash_table *ht, struct entry *e) |
66a63635 JT |
612 | { |
613 | return to_entry(ht->es, e->hash_next); | |
614 | } | |
615 | ||
b29d4986 | 616 | static void __h_insert(struct smq_hash_table *ht, unsigned bucket, struct entry *e) |
66a63635 JT |
617 | { |
618 | e->hash_next = ht->buckets[bucket]; | |
619 | ht->buckets[bucket] = to_index(ht->es, e); | |
620 | } | |
621 | ||
b29d4986 | 622 | static void h_insert(struct smq_hash_table *ht, struct entry *e) |
66a63635 JT |
623 | { |
624 | unsigned h = hash_64(from_oblock(e->oblock), ht->hash_bits); | |
625 | __h_insert(ht, h, e); | |
626 | } | |
627 | ||
b29d4986 | 628 | static struct entry *__h_lookup(struct smq_hash_table *ht, unsigned h, dm_oblock_t oblock, |
66a63635 JT |
629 | struct entry **prev) |
630 | { | |
631 | struct entry *e; | |
632 | ||
633 | *prev = NULL; | |
634 | for (e = h_head(ht, h); e; e = h_next(ht, e)) { | |
635 | if (e->oblock == oblock) | |
636 | return e; | |
637 | ||
638 | *prev = e; | |
639 | } | |
640 | ||
641 | return NULL; | |
642 | } | |
643 | ||
b29d4986 | 644 | static void __h_unlink(struct smq_hash_table *ht, unsigned h, |
66a63635 JT |
645 | struct entry *e, struct entry *prev) |
646 | { | |
647 | if (prev) | |
648 | prev->hash_next = e->hash_next; | |
649 | else | |
650 | ht->buckets[h] = e->hash_next; | |
651 | } | |
652 | ||
653 | /* | |
654 | * Also moves each entry to the front of the bucket. | |
655 | */ | |
b29d4986 | 656 | static struct entry *h_lookup(struct smq_hash_table *ht, dm_oblock_t oblock) |
66a63635 JT |
657 | { |
658 | struct entry *e, *prev; | |
659 | unsigned h = hash_64(from_oblock(oblock), ht->hash_bits); | |
660 | ||
661 | e = __h_lookup(ht, h, oblock, &prev); | |
662 | if (e && prev) { | |
663 | /* | |
664 | * Move to the front because this entry is likely | |
665 | * to be hit again. | |
666 | */ | |
667 | __h_unlink(ht, h, e, prev); | |
668 | __h_insert(ht, h, e); | |
669 | } | |
670 | ||
671 | return e; | |
672 | } | |
673 | ||
b29d4986 | 674 | static void h_remove(struct smq_hash_table *ht, struct entry *e) |
66a63635 JT |
675 | { |
676 | unsigned h = hash_64(from_oblock(e->oblock), ht->hash_bits); | |
677 | struct entry *prev; | |
678 | ||
679 | /* | |
680 | * The down side of using a singly linked list is we have to | |
681 | * iterate the bucket to remove an item. | |
682 | */ | |
683 | e = __h_lookup(ht, h, e->oblock, &prev); | |
684 | if (e) | |
685 | __h_unlink(ht, h, e, prev); | |
686 | } | |
687 | ||
688 | /*----------------------------------------------------------------*/ | |
689 | ||
690 | struct entry_alloc { | |
691 | struct entry_space *es; | |
692 | unsigned begin; | |
693 | ||
694 | unsigned nr_allocated; | |
695 | struct ilist free; | |
696 | }; | |
697 | ||
698 | static void init_allocator(struct entry_alloc *ea, struct entry_space *es, | |
699 | unsigned begin, unsigned end) | |
700 | { | |
701 | unsigned i; | |
702 | ||
703 | ea->es = es; | |
704 | ea->nr_allocated = 0u; | |
705 | ea->begin = begin; | |
706 | ||
707 | l_init(&ea->free); | |
708 | for (i = begin; i != end; i++) | |
709 | l_add_tail(ea->es, &ea->free, __get_entry(ea->es, i)); | |
710 | } | |
711 | ||
712 | static void init_entry(struct entry *e) | |
713 | { | |
714 | /* | |
715 | * We can't memset because that would clear the hotspot and | |
716 | * sentinel bits which remain constant. | |
717 | */ | |
718 | e->hash_next = INDEXER_NULL; | |
719 | e->next = INDEXER_NULL; | |
720 | e->prev = INDEXER_NULL; | |
721 | e->level = 0u; | |
b29d4986 | 722 | e->dirty = true; /* FIXME: audit */ |
66a63635 | 723 | e->allocated = true; |
b29d4986 JT |
724 | e->sentinel = false; |
725 | e->pending_work = false; | |
66a63635 JT |
726 | } |
727 | ||
728 | static struct entry *alloc_entry(struct entry_alloc *ea) | |
729 | { | |
730 | struct entry *e; | |
731 | ||
732 | if (l_empty(&ea->free)) | |
733 | return NULL; | |
734 | ||
9768a10d | 735 | e = l_pop_head(ea->es, &ea->free); |
66a63635 JT |
736 | init_entry(e); |
737 | ea->nr_allocated++; | |
738 | ||
739 | return e; | |
740 | } | |
741 | ||
742 | /* | |
743 | * This assumes the cblock hasn't already been allocated. | |
744 | */ | |
745 | static struct entry *alloc_particular_entry(struct entry_alloc *ea, unsigned i) | |
746 | { | |
747 | struct entry *e = __get_entry(ea->es, ea->begin + i); | |
748 | ||
749 | BUG_ON(e->allocated); | |
750 | ||
751 | l_del(ea->es, &ea->free, e); | |
752 | init_entry(e); | |
753 | ea->nr_allocated++; | |
754 | ||
755 | return e; | |
756 | } | |
757 | ||
758 | static void free_entry(struct entry_alloc *ea, struct entry *e) | |
759 | { | |
760 | BUG_ON(!ea->nr_allocated); | |
761 | BUG_ON(!e->allocated); | |
762 | ||
763 | ea->nr_allocated--; | |
764 | e->allocated = false; | |
765 | l_add_tail(ea->es, &ea->free, e); | |
766 | } | |
767 | ||
768 | static bool allocator_empty(struct entry_alloc *ea) | |
769 | { | |
770 | return l_empty(&ea->free); | |
771 | } | |
772 | ||
773 | static unsigned get_index(struct entry_alloc *ea, struct entry *e) | |
774 | { | |
775 | return to_index(ea->es, e) - ea->begin; | |
776 | } | |
777 | ||
778 | static struct entry *get_entry(struct entry_alloc *ea, unsigned index) | |
779 | { | |
780 | return __get_entry(ea->es, ea->begin + index); | |
781 | } | |
782 | ||
783 | /*----------------------------------------------------------------*/ | |
784 | ||
785 | #define NR_HOTSPOT_LEVELS 64u | |
786 | #define NR_CACHE_LEVELS 64u | |
787 | ||
b29d4986 JT |
788 | #define WRITEBACK_PERIOD (10ul * HZ) |
789 | #define DEMOTE_PERIOD (60ul * HZ) | |
66a63635 JT |
790 | |
791 | #define HOTSPOT_UPDATE_PERIOD (HZ) | |
b29d4986 | 792 | #define CACHE_UPDATE_PERIOD (60ul * HZ) |
66a63635 JT |
793 | |
794 | struct smq_policy { | |
795 | struct dm_cache_policy policy; | |
796 | ||
797 | /* protects everything */ | |
4051aab7 | 798 | spinlock_t lock; |
66a63635 JT |
799 | dm_cblock_t cache_size; |
800 | sector_t cache_block_size; | |
801 | ||
802 | sector_t hotspot_block_size; | |
803 | unsigned nr_hotspot_blocks; | |
804 | unsigned cache_blocks_per_hotspot_block; | |
805 | unsigned hotspot_level_jump; | |
806 | ||
807 | struct entry_space es; | |
808 | struct entry_alloc writeback_sentinel_alloc; | |
809 | struct entry_alloc demote_sentinel_alloc; | |
810 | struct entry_alloc hotspot_alloc; | |
811 | struct entry_alloc cache_alloc; | |
812 | ||
813 | unsigned long *hotspot_hit_bits; | |
814 | unsigned long *cache_hit_bits; | |
815 | ||
816 | /* | |
817 | * We maintain three queues of entries. The cache proper, | |
818 | * consisting of a clean and dirty queue, containing the currently | |
819 | * active mappings. The hotspot queue uses a larger block size to | |
820 | * track blocks that are being hit frequently and potential | |
821 | * candidates for promotion to the cache. | |
822 | */ | |
823 | struct queue hotspot; | |
824 | struct queue clean; | |
825 | struct queue dirty; | |
826 | ||
827 | struct stats hotspot_stats; | |
828 | struct stats cache_stats; | |
829 | ||
830 | /* | |
831 | * Keeps track of time, incremented by the core. We use this to | |
832 | * avoid attributing multiple hits within the same tick. | |
66a63635 | 833 | */ |
66a63635 JT |
834 | unsigned tick; |
835 | ||
836 | /* | |
837 | * The hash tables allows us to quickly find an entry by origin | |
838 | * block. | |
839 | */ | |
b29d4986 JT |
840 | struct smq_hash_table table; |
841 | struct smq_hash_table hotspot_table; | |
66a63635 JT |
842 | |
843 | bool current_writeback_sentinels; | |
844 | unsigned long next_writeback_period; | |
845 | ||
846 | bool current_demote_sentinels; | |
847 | unsigned long next_demote_period; | |
848 | ||
849 | unsigned write_promote_level; | |
850 | unsigned read_promote_level; | |
851 | ||
852 | unsigned long next_hotspot_period; | |
853 | unsigned long next_cache_period; | |
b29d4986 JT |
854 | |
855 | struct background_tracker *bg_work; | |
856 | ||
857 | bool migrations_allowed; | |
66a63635 JT |
858 | }; |
859 | ||
860 | /*----------------------------------------------------------------*/ | |
861 | ||
862 | static struct entry *get_sentinel(struct entry_alloc *ea, unsigned level, bool which) | |
863 | { | |
864 | return get_entry(ea, which ? level : NR_CACHE_LEVELS + level); | |
865 | } | |
866 | ||
867 | static struct entry *writeback_sentinel(struct smq_policy *mq, unsigned level) | |
868 | { | |
869 | return get_sentinel(&mq->writeback_sentinel_alloc, level, mq->current_writeback_sentinels); | |
870 | } | |
871 | ||
872 | static struct entry *demote_sentinel(struct smq_policy *mq, unsigned level) | |
873 | { | |
874 | return get_sentinel(&mq->demote_sentinel_alloc, level, mq->current_demote_sentinels); | |
875 | } | |
876 | ||
877 | static void __update_writeback_sentinels(struct smq_policy *mq) | |
878 | { | |
879 | unsigned level; | |
880 | struct queue *q = &mq->dirty; | |
881 | struct entry *sentinel; | |
882 | ||
883 | for (level = 0; level < q->nr_levels; level++) { | |
884 | sentinel = writeback_sentinel(mq, level); | |
885 | q_del(q, sentinel); | |
886 | q_push(q, sentinel); | |
887 | } | |
888 | } | |
889 | ||
890 | static void __update_demote_sentinels(struct smq_policy *mq) | |
891 | { | |
892 | unsigned level; | |
893 | struct queue *q = &mq->clean; | |
894 | struct entry *sentinel; | |
895 | ||
896 | for (level = 0; level < q->nr_levels; level++) { | |
897 | sentinel = demote_sentinel(mq, level); | |
898 | q_del(q, sentinel); | |
899 | q_push(q, sentinel); | |
900 | } | |
901 | } | |
902 | ||
903 | static void update_sentinels(struct smq_policy *mq) | |
904 | { | |
905 | if (time_after(jiffies, mq->next_writeback_period)) { | |
66a63635 JT |
906 | mq->next_writeback_period = jiffies + WRITEBACK_PERIOD; |
907 | mq->current_writeback_sentinels = !mq->current_writeback_sentinels; | |
b29d4986 | 908 | __update_writeback_sentinels(mq); |
66a63635 JT |
909 | } |
910 | ||
911 | if (time_after(jiffies, mq->next_demote_period)) { | |
66a63635 JT |
912 | mq->next_demote_period = jiffies + DEMOTE_PERIOD; |
913 | mq->current_demote_sentinels = !mq->current_demote_sentinels; | |
b29d4986 | 914 | __update_demote_sentinels(mq); |
66a63635 JT |
915 | } |
916 | } | |
917 | ||
918 | static void __sentinels_init(struct smq_policy *mq) | |
919 | { | |
920 | unsigned level; | |
921 | struct entry *sentinel; | |
922 | ||
923 | for (level = 0; level < NR_CACHE_LEVELS; level++) { | |
924 | sentinel = writeback_sentinel(mq, level); | |
925 | sentinel->level = level; | |
926 | q_push(&mq->dirty, sentinel); | |
927 | ||
928 | sentinel = demote_sentinel(mq, level); | |
929 | sentinel->level = level; | |
930 | q_push(&mq->clean, sentinel); | |
931 | } | |
932 | } | |
933 | ||
934 | static void sentinels_init(struct smq_policy *mq) | |
935 | { | |
936 | mq->next_writeback_period = jiffies + WRITEBACK_PERIOD; | |
937 | mq->next_demote_period = jiffies + DEMOTE_PERIOD; | |
938 | ||
939 | mq->current_writeback_sentinels = false; | |
940 | mq->current_demote_sentinels = false; | |
941 | __sentinels_init(mq); | |
942 | ||
943 | mq->current_writeback_sentinels = !mq->current_writeback_sentinels; | |
944 | mq->current_demote_sentinels = !mq->current_demote_sentinels; | |
945 | __sentinels_init(mq); | |
946 | } | |
947 | ||
948 | /*----------------------------------------------------------------*/ | |
949 | ||
b29d4986 | 950 | static void del_queue(struct smq_policy *mq, struct entry *e) |
66a63635 | 951 | { |
b29d4986 | 952 | q_del(e->dirty ? &mq->dirty : &mq->clean, e); |
66a63635 JT |
953 | } |
954 | ||
b29d4986 | 955 | static void push_queue(struct smq_policy *mq, struct entry *e) |
66a63635 | 956 | { |
b29d4986 JT |
957 | if (e->dirty) |
958 | q_push(&mq->dirty, e); | |
959 | else | |
960 | q_push(&mq->clean, e); | |
66a63635 JT |
961 | } |
962 | ||
b29d4986 JT |
963 | // !h, !q, a -> h, q, a |
964 | static void push(struct smq_policy *mq, struct entry *e) | |
66a63635 | 965 | { |
b29d4986 JT |
966 | h_insert(&mq->table, e); |
967 | if (!e->pending_work) | |
968 | push_queue(mq, e); | |
66a63635 JT |
969 | } |
970 | ||
b29d4986 | 971 | static void push_queue_front(struct smq_policy *mq, struct entry *e) |
66a63635 | 972 | { |
b29d4986 JT |
973 | if (e->dirty) |
974 | q_push_front(&mq->dirty, e); | |
975 | else | |
976 | q_push_front(&mq->clean, e); | |
66a63635 JT |
977 | } |
978 | ||
b29d4986 | 979 | static void push_front(struct smq_policy *mq, struct entry *e) |
66a63635 | 980 | { |
b29d4986 JT |
981 | h_insert(&mq->table, e); |
982 | if (!e->pending_work) | |
983 | push_queue_front(mq, e); | |
66a63635 JT |
984 | } |
985 | ||
986 | static dm_cblock_t infer_cblock(struct smq_policy *mq, struct entry *e) | |
987 | { | |
988 | return to_cblock(get_index(&mq->cache_alloc, e)); | |
989 | } | |
990 | ||
991 | static void requeue(struct smq_policy *mq, struct entry *e) | |
992 | { | |
b29d4986 JT |
993 | /* |
994 | * Pending work has temporarily been taken out of the queues. | |
995 | */ | |
996 | if (e->pending_work) | |
997 | return; | |
66a63635 JT |
998 | |
999 | if (!test_and_set_bit(from_cblock(infer_cblock(mq, e)), mq->cache_hit_bits)) { | |
b29d4986 JT |
1000 | if (!e->dirty) { |
1001 | q_requeue(&mq->clean, e, 1u, NULL, NULL); | |
1002 | return; | |
66a63635 | 1003 | } |
b29d4986 JT |
1004 | |
1005 | q_requeue(&mq->dirty, e, 1u, | |
1006 | get_sentinel(&mq->writeback_sentinel_alloc, e->level, !mq->current_writeback_sentinels), | |
1007 | get_sentinel(&mq->writeback_sentinel_alloc, e->level, mq->current_writeback_sentinels)); | |
66a63635 JT |
1008 | } |
1009 | } | |
1010 | ||
1011 | static unsigned default_promote_level(struct smq_policy *mq) | |
1012 | { | |
1013 | /* | |
1014 | * The promote level depends on the current performance of the | |
1015 | * cache. | |
1016 | * | |
1017 | * If the cache is performing badly, then we can't afford | |
1018 | * to promote much without causing performance to drop below that | |
1019 | * of the origin device. | |
1020 | * | |
1021 | * If the cache is performing well, then we don't need to promote | |
1022 | * much. If it isn't broken, don't fix it. | |
1023 | * | |
1024 | * If the cache is middling then we promote more. | |
1025 | * | |
1026 | * This scheme reminds me of a graph of entropy vs probability of a | |
1027 | * binary variable. | |
1028 | */ | |
1029 | static unsigned table[] = {1, 1, 1, 2, 4, 6, 7, 8, 7, 6, 4, 4, 3, 3, 2, 2, 1}; | |
1030 | ||
1031 | unsigned hits = mq->cache_stats.hits; | |
1032 | unsigned misses = mq->cache_stats.misses; | |
1033 | unsigned index = safe_div(hits << 4u, hits + misses); | |
1034 | return table[index]; | |
1035 | } | |
1036 | ||
1037 | static void update_promote_levels(struct smq_policy *mq) | |
1038 | { | |
1039 | /* | |
1040 | * If there are unused cache entries then we want to be really | |
1041 | * eager to promote. | |
1042 | */ | |
1043 | unsigned threshold_level = allocator_empty(&mq->cache_alloc) ? | |
1044 | default_promote_level(mq) : (NR_HOTSPOT_LEVELS / 2u); | |
1045 | ||
b29d4986 JT |
1046 | threshold_level = max(threshold_level, NR_HOTSPOT_LEVELS); |
1047 | ||
66a63635 JT |
1048 | /* |
1049 | * If the hotspot queue is performing badly then we have little | |
1050 | * confidence that we know which blocks to promote. So we cut down | |
1051 | * the amount of promotions. | |
1052 | */ | |
1053 | switch (stats_assess(&mq->hotspot_stats)) { | |
1054 | case Q_POOR: | |
1055 | threshold_level /= 4u; | |
1056 | break; | |
1057 | ||
1058 | case Q_FAIR: | |
1059 | threshold_level /= 2u; | |
1060 | break; | |
1061 | ||
1062 | case Q_WELL: | |
1063 | break; | |
1064 | } | |
1065 | ||
1066 | mq->read_promote_level = NR_HOTSPOT_LEVELS - threshold_level; | |
b29d4986 | 1067 | mq->write_promote_level = (NR_HOTSPOT_LEVELS - threshold_level); |
66a63635 JT |
1068 | } |
1069 | ||
1070 | /* | |
1071 | * If the hotspot queue is performing badly, then we try and move entries | |
1072 | * around more quickly. | |
1073 | */ | |
1074 | static void update_level_jump(struct smq_policy *mq) | |
1075 | { | |
1076 | switch (stats_assess(&mq->hotspot_stats)) { | |
1077 | case Q_POOR: | |
1078 | mq->hotspot_level_jump = 4u; | |
1079 | break; | |
1080 | ||
1081 | case Q_FAIR: | |
1082 | mq->hotspot_level_jump = 2u; | |
1083 | break; | |
1084 | ||
1085 | case Q_WELL: | |
1086 | mq->hotspot_level_jump = 1u; | |
1087 | break; | |
1088 | } | |
1089 | } | |
1090 | ||
1091 | static void end_hotspot_period(struct smq_policy *mq) | |
1092 | { | |
1093 | clear_bitset(mq->hotspot_hit_bits, mq->nr_hotspot_blocks); | |
1094 | update_promote_levels(mq); | |
1095 | ||
1096 | if (time_after(jiffies, mq->next_hotspot_period)) { | |
1097 | update_level_jump(mq); | |
1098 | q_redistribute(&mq->hotspot); | |
1099 | stats_reset(&mq->hotspot_stats); | |
1100 | mq->next_hotspot_period = jiffies + HOTSPOT_UPDATE_PERIOD; | |
1101 | } | |
1102 | } | |
1103 | ||
1104 | static void end_cache_period(struct smq_policy *mq) | |
1105 | { | |
1106 | if (time_after(jiffies, mq->next_cache_period)) { | |
1107 | clear_bitset(mq->cache_hit_bits, from_cblock(mq->cache_size)); | |
1108 | ||
1109 | q_redistribute(&mq->dirty); | |
1110 | q_redistribute(&mq->clean); | |
1111 | stats_reset(&mq->cache_stats); | |
1112 | ||
1113 | mq->next_cache_period = jiffies + CACHE_UPDATE_PERIOD; | |
1114 | } | |
1115 | } | |
1116 | ||
b29d4986 JT |
1117 | /*----------------------------------------------------------------*/ |
1118 | ||
1119 | /* | |
1120 | * Targets are given as a percentage. | |
1121 | */ | |
1122 | #define CLEAN_TARGET 25u | |
1123 | #define FREE_TARGET 25u | |
1124 | ||
1125 | static unsigned percent_to_target(struct smq_policy *mq, unsigned p) | |
66a63635 | 1126 | { |
b29d4986 JT |
1127 | return from_cblock(mq->cache_size) * p / 100u; |
1128 | } | |
1129 | ||
1130 | static bool clean_target_met(struct smq_policy *mq, bool idle) | |
1131 | { | |
1132 | /* | |
1133 | * Cache entries may not be populated. So we cannot rely on the | |
1134 | * size of the clean queue. | |
1135 | */ | |
97dfb203 | 1136 | if (idle) { |
66a63635 | 1137 | /* |
b29d4986 | 1138 | * We'd like to clean everything. |
66a63635 | 1139 | */ |
b29d4986 | 1140 | return q_size(&mq->dirty) == 0u; |
97dfb203 MS |
1141 | } |
1142 | ||
2e633095 JT |
1143 | /* |
1144 | * If we're busy we don't worry about cleaning at all. | |
1145 | */ | |
1146 | return true; | |
b29d4986 | 1147 | } |
66a63635 | 1148 | |
6cf4cc8f | 1149 | static bool free_target_met(struct smq_policy *mq) |
b29d4986 | 1150 | { |
97dfb203 | 1151 | unsigned nr_free; |
66a63635 | 1152 | |
97dfb203 MS |
1153 | nr_free = from_cblock(mq->cache_size) - mq->cache_alloc.nr_allocated; |
1154 | return (nr_free + btracker_nr_demotions_queued(mq->bg_work)) >= | |
1155 | percent_to_target(mq, FREE_TARGET); | |
66a63635 JT |
1156 | } |
1157 | ||
b29d4986 JT |
1158 | /*----------------------------------------------------------------*/ |
1159 | ||
1160 | static void mark_pending(struct smq_policy *mq, struct entry *e) | |
1161 | { | |
1162 | BUG_ON(e->sentinel); | |
1163 | BUG_ON(!e->allocated); | |
1164 | BUG_ON(e->pending_work); | |
1165 | e->pending_work = true; | |
1166 | } | |
1167 | ||
1168 | static void clear_pending(struct smq_policy *mq, struct entry *e) | |
1169 | { | |
1170 | BUG_ON(!e->pending_work); | |
1171 | e->pending_work = false; | |
1172 | } | |
1173 | ||
deb71918 | 1174 | static void queue_writeback(struct smq_policy *mq, bool idle) |
b29d4986 JT |
1175 | { |
1176 | int r; | |
1177 | struct policy_work work; | |
1178 | struct entry *e; | |
1179 | ||
deb71918 | 1180 | e = q_peek(&mq->dirty, mq->dirty.nr_levels, idle); |
b29d4986 JT |
1181 | if (e) { |
1182 | mark_pending(mq, e); | |
1183 | q_del(&mq->dirty, e); | |
1184 | ||
1185 | work.op = POLICY_WRITEBACK; | |
1186 | work.oblock = e->oblock; | |
1187 | work.cblock = infer_cblock(mq, e); | |
1188 | ||
1189 | r = btracker_queue(mq->bg_work, &work, NULL); | |
1e72a8e8 JT |
1190 | if (r) { |
1191 | clear_pending(mq, e); | |
1192 | q_push_front(&mq->dirty, e); | |
1193 | } | |
b29d4986 JT |
1194 | } |
1195 | } | |
1196 | ||
1197 | static void queue_demotion(struct smq_policy *mq) | |
1198 | { | |
1e72a8e8 | 1199 | int r; |
b29d4986 JT |
1200 | struct policy_work work; |
1201 | struct entry *e; | |
1202 | ||
bab5d988 | 1203 | if (WARN_ON_ONCE(!mq->migrations_allowed)) |
b29d4986 JT |
1204 | return; |
1205 | ||
a8cd1eba | 1206 | e = q_peek(&mq->clean, mq->clean.nr_levels / 2, true); |
b29d4986 | 1207 | if (!e) { |
78c45607 | 1208 | if (!clean_target_met(mq, true)) |
deb71918 | 1209 | queue_writeback(mq, false); |
b29d4986 JT |
1210 | return; |
1211 | } | |
1212 | ||
1213 | mark_pending(mq, e); | |
1214 | q_del(&mq->clean, e); | |
1215 | ||
1216 | work.op = POLICY_DEMOTE; | |
1217 | work.oblock = e->oblock; | |
1218 | work.cblock = infer_cblock(mq, e); | |
1e72a8e8 JT |
1219 | r = btracker_queue(mq->bg_work, &work, NULL); |
1220 | if (r) { | |
1221 | clear_pending(mq, e); | |
1222 | q_push_front(&mq->clean, e); | |
1223 | } | |
b29d4986 JT |
1224 | } |
1225 | ||
1226 | static void queue_promotion(struct smq_policy *mq, dm_oblock_t oblock, | |
1227 | struct policy_work **workp) | |
1228 | { | |
1e72a8e8 | 1229 | int r; |
b29d4986 JT |
1230 | struct entry *e; |
1231 | struct policy_work work; | |
1232 | ||
1233 | if (!mq->migrations_allowed) | |
1234 | return; | |
1235 | ||
1236 | if (allocator_empty(&mq->cache_alloc)) { | |
ce1d64e8 JT |
1237 | /* |
1238 | * We always claim to be 'idle' to ensure some demotions happen | |
1239 | * with continuous loads. | |
1240 | */ | |
6cf4cc8f | 1241 | if (!free_target_met(mq)) |
b29d4986 JT |
1242 | queue_demotion(mq); |
1243 | return; | |
1244 | } | |
1245 | ||
1246 | if (btracker_promotion_already_present(mq->bg_work, oblock)) | |
1247 | return; | |
1248 | ||
1249 | /* | |
1250 | * We allocate the entry now to reserve the cblock. If the | |
1251 | * background work is aborted we must remember to free it. | |
1252 | */ | |
1253 | e = alloc_entry(&mq->cache_alloc); | |
1254 | BUG_ON(!e); | |
1255 | e->pending_work = true; | |
1256 | work.op = POLICY_PROMOTE; | |
1257 | work.oblock = oblock; | |
1258 | work.cblock = infer_cblock(mq, e); | |
1e72a8e8 JT |
1259 | r = btracker_queue(mq->bg_work, &work, workp); |
1260 | if (r) | |
1261 | free_entry(&mq->cache_alloc, e); | |
b29d4986 JT |
1262 | } |
1263 | ||
1264 | /*----------------------------------------------------------------*/ | |
1265 | ||
66a63635 JT |
1266 | enum promote_result { |
1267 | PROMOTE_NOT, | |
1268 | PROMOTE_TEMPORARY, | |
1269 | PROMOTE_PERMANENT | |
1270 | }; | |
1271 | ||
1272 | /* | |
1273 | * Converts a boolean into a promote result. | |
1274 | */ | |
1275 | static enum promote_result maybe_promote(bool promote) | |
1276 | { | |
1277 | return promote ? PROMOTE_PERMANENT : PROMOTE_NOT; | |
1278 | } | |
1279 | ||
b29d4986 JT |
1280 | static enum promote_result should_promote(struct smq_policy *mq, struct entry *hs_e, |
1281 | int data_dir, bool fast_promote) | |
66a63635 | 1282 | { |
b29d4986 | 1283 | if (data_dir == WRITE) { |
66a63635 JT |
1284 | if (!allocator_empty(&mq->cache_alloc) && fast_promote) |
1285 | return PROMOTE_TEMPORARY; | |
1286 | ||
b29d4986 | 1287 | return maybe_promote(hs_e->level >= mq->write_promote_level); |
66a63635 JT |
1288 | } else |
1289 | return maybe_promote(hs_e->level >= mq->read_promote_level); | |
1290 | } | |
1291 | ||
66a63635 JT |
1292 | static dm_oblock_t to_hblock(struct smq_policy *mq, dm_oblock_t b) |
1293 | { | |
1294 | sector_t r = from_oblock(b); | |
1295 | (void) sector_div(r, mq->cache_blocks_per_hotspot_block); | |
1296 | return to_oblock(r); | |
1297 | } | |
1298 | ||
b29d4986 | 1299 | static struct entry *update_hotspot_queue(struct smq_policy *mq, dm_oblock_t b) |
66a63635 JT |
1300 | { |
1301 | unsigned hi; | |
1302 | dm_oblock_t hb = to_hblock(mq, b); | |
1303 | struct entry *e = h_lookup(&mq->hotspot_table, hb); | |
1304 | ||
1305 | if (e) { | |
1306 | stats_level_accessed(&mq->hotspot_stats, e->level); | |
1307 | ||
1308 | hi = get_index(&mq->hotspot_alloc, e); | |
1309 | q_requeue(&mq->hotspot, e, | |
1310 | test_and_set_bit(hi, mq->hotspot_hit_bits) ? | |
b29d4986 JT |
1311 | 0u : mq->hotspot_level_jump, |
1312 | NULL, NULL); | |
66a63635 JT |
1313 | |
1314 | } else { | |
1315 | stats_miss(&mq->hotspot_stats); | |
1316 | ||
1317 | e = alloc_entry(&mq->hotspot_alloc); | |
1318 | if (!e) { | |
1319 | e = q_pop(&mq->hotspot); | |
1320 | if (e) { | |
1321 | h_remove(&mq->hotspot_table, e); | |
1322 | hi = get_index(&mq->hotspot_alloc, e); | |
1323 | clear_bit(hi, mq->hotspot_hit_bits); | |
1324 | } | |
1325 | ||
1326 | } | |
1327 | ||
1328 | if (e) { | |
1329 | e->oblock = hb; | |
1330 | q_push(&mq->hotspot, e); | |
1331 | h_insert(&mq->hotspot_table, e); | |
1332 | } | |
1333 | } | |
1334 | ||
1335 | return e; | |
1336 | } | |
1337 | ||
66a63635 JT |
1338 | /*----------------------------------------------------------------*/ |
1339 | ||
1340 | /* | |
1341 | * Public interface, via the policy struct. See dm-cache-policy.h for a | |
1342 | * description of these. | |
1343 | */ | |
1344 | ||
1345 | static struct smq_policy *to_smq_policy(struct dm_cache_policy *p) | |
1346 | { | |
1347 | return container_of(p, struct smq_policy, policy); | |
1348 | } | |
1349 | ||
1350 | static void smq_destroy(struct dm_cache_policy *p) | |
1351 | { | |
1352 | struct smq_policy *mq = to_smq_policy(p); | |
1353 | ||
b29d4986 | 1354 | btracker_destroy(mq->bg_work); |
66a63635 JT |
1355 | h_exit(&mq->hotspot_table); |
1356 | h_exit(&mq->table); | |
1357 | free_bitset(mq->hotspot_hit_bits); | |
1358 | free_bitset(mq->cache_hit_bits); | |
1359 | space_exit(&mq->es); | |
1360 | kfree(mq); | |
1361 | } | |
1362 | ||
b29d4986 | 1363 | /*----------------------------------------------------------------*/ |
66a63635 | 1364 | |
b29d4986 JT |
1365 | static int __lookup(struct smq_policy *mq, dm_oblock_t oblock, dm_cblock_t *cblock, |
1366 | int data_dir, bool fast_copy, | |
1367 | struct policy_work **work, bool *background_work) | |
66a63635 | 1368 | { |
b29d4986 JT |
1369 | struct entry *e, *hs_e; |
1370 | enum promote_result pr; | |
1371 | ||
1372 | *background_work = false; | |
66a63635 | 1373 | |
66a63635 JT |
1374 | e = h_lookup(&mq->table, oblock); |
1375 | if (e) { | |
b29d4986 JT |
1376 | stats_level_accessed(&mq->cache_stats, e->level); |
1377 | ||
1378 | requeue(mq, e); | |
66a63635 | 1379 | *cblock = infer_cblock(mq, e); |
b29d4986 | 1380 | return 0; |
66a63635 | 1381 | |
b29d4986 JT |
1382 | } else { |
1383 | stats_miss(&mq->cache_stats); | |
66a63635 | 1384 | |
b29d4986 JT |
1385 | /* |
1386 | * The hotspot queue only gets updated with misses. | |
1387 | */ | |
1388 | hs_e = update_hotspot_queue(mq, oblock); | |
66a63635 | 1389 | |
b29d4986 JT |
1390 | pr = should_promote(mq, hs_e, data_dir, fast_copy); |
1391 | if (pr != PROMOTE_NOT) { | |
1392 | queue_promotion(mq, oblock, work); | |
1393 | *background_work = true; | |
1394 | } | |
66a63635 | 1395 | |
b29d4986 JT |
1396 | return -ENOENT; |
1397 | } | |
66a63635 JT |
1398 | } |
1399 | ||
b29d4986 JT |
1400 | static int smq_lookup(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock, |
1401 | int data_dir, bool fast_copy, | |
1402 | bool *background_work) | |
66a63635 | 1403 | { |
b29d4986 | 1404 | int r; |
4051aab7 | 1405 | unsigned long flags; |
66a63635 JT |
1406 | struct smq_policy *mq = to_smq_policy(p); |
1407 | ||
4051aab7 | 1408 | spin_lock_irqsave(&mq->lock, flags); |
b29d4986 JT |
1409 | r = __lookup(mq, oblock, cblock, |
1410 | data_dir, fast_copy, | |
1411 | NULL, background_work); | |
4051aab7 | 1412 | spin_unlock_irqrestore(&mq->lock, flags); |
b29d4986 JT |
1413 | |
1414 | return r; | |
66a63635 JT |
1415 | } |
1416 | ||
b29d4986 JT |
1417 | static int smq_lookup_with_work(struct dm_cache_policy *p, |
1418 | dm_oblock_t oblock, dm_cblock_t *cblock, | |
1419 | int data_dir, bool fast_copy, | |
1420 | struct policy_work **work) | |
66a63635 | 1421 | { |
b29d4986 JT |
1422 | int r; |
1423 | bool background_queued; | |
4051aab7 | 1424 | unsigned long flags; |
b29d4986 | 1425 | struct smq_policy *mq = to_smq_policy(p); |
66a63635 | 1426 | |
4051aab7 | 1427 | spin_lock_irqsave(&mq->lock, flags); |
b29d4986 | 1428 | r = __lookup(mq, oblock, cblock, data_dir, fast_copy, work, &background_queued); |
4051aab7 | 1429 | spin_unlock_irqrestore(&mq->lock, flags); |
66a63635 | 1430 | |
b29d4986 | 1431 | return r; |
9d1b404c JT |
1432 | } |
1433 | ||
b29d4986 JT |
1434 | static int smq_get_background_work(struct dm_cache_policy *p, bool idle, |
1435 | struct policy_work **result) | |
66a63635 | 1436 | { |
b29d4986 JT |
1437 | int r; |
1438 | unsigned long flags; | |
66a63635 | 1439 | struct smq_policy *mq = to_smq_policy(p); |
66a63635 | 1440 | |
b29d4986 JT |
1441 | spin_lock_irqsave(&mq->lock, flags); |
1442 | r = btracker_issue(mq->bg_work, result); | |
1443 | if (r == -ENODATA) { | |
6cf4cc8f | 1444 | if (!clean_target_met(mq, idle)) { |
deb71918 | 1445 | queue_writeback(mq, idle); |
6cf4cc8f JT |
1446 | r = btracker_issue(mq->bg_work, result); |
1447 | } | |
b29d4986 JT |
1448 | } |
1449 | spin_unlock_irqrestore(&mq->lock, flags); | |
66a63635 | 1450 | |
b29d4986 | 1451 | return r; |
66a63635 JT |
1452 | } |
1453 | ||
b29d4986 JT |
1454 | /* |
1455 | * We need to clear any pending work flags that have been set, and in the | |
1456 | * case of promotion free the entry for the destination cblock. | |
1457 | */ | |
1458 | static void __complete_background_work(struct smq_policy *mq, | |
1459 | struct policy_work *work, | |
1460 | bool success) | |
1461 | { | |
1462 | struct entry *e = get_entry(&mq->cache_alloc, | |
1463 | from_cblock(work->cblock)); | |
1464 | ||
1465 | switch (work->op) { | |
1466 | case POLICY_PROMOTE: | |
1467 | // !h, !q, a | |
1468 | clear_pending(mq, e); | |
1469 | if (success) { | |
1470 | e->oblock = work->oblock; | |
4d44ec5a | 1471 | e->level = NR_CACHE_LEVELS - 1; |
b29d4986 JT |
1472 | push(mq, e); |
1473 | // h, q, a | |
1474 | } else { | |
1475 | free_entry(&mq->cache_alloc, e); | |
1476 | // !h, !q, !a | |
1477 | } | |
1478 | break; | |
66a63635 | 1479 | |
b29d4986 JT |
1480 | case POLICY_DEMOTE: |
1481 | // h, !q, a | |
1482 | if (success) { | |
1483 | h_remove(&mq->table, e); | |
1484 | free_entry(&mq->cache_alloc, e); | |
1485 | // !h, !q, !a | |
1486 | } else { | |
1487 | clear_pending(mq, e); | |
1488 | push_queue(mq, e); | |
1489 | // h, q, a | |
1490 | } | |
1491 | break; | |
66a63635 | 1492 | |
b29d4986 JT |
1493 | case POLICY_WRITEBACK: |
1494 | // h, !q, a | |
1495 | clear_pending(mq, e); | |
1496 | push_queue(mq, e); | |
1497 | // h, q, a | |
1498 | break; | |
1499 | } | |
1500 | ||
1501 | btracker_complete(mq->bg_work, work); | |
66a63635 JT |
1502 | } |
1503 | ||
b29d4986 JT |
1504 | static void smq_complete_background_work(struct dm_cache_policy *p, |
1505 | struct policy_work *work, | |
1506 | bool success) | |
66a63635 | 1507 | { |
4051aab7 | 1508 | unsigned long flags; |
b29d4986 | 1509 | struct smq_policy *mq = to_smq_policy(p); |
66a63635 | 1510 | |
4051aab7 | 1511 | spin_lock_irqsave(&mq->lock, flags); |
b29d4986 | 1512 | __complete_background_work(mq, work, success); |
4051aab7 | 1513 | spin_unlock_irqrestore(&mq->lock, flags); |
66a63635 JT |
1514 | } |
1515 | ||
b29d4986 JT |
1516 | // in_hash(oblock) -> in_hash(oblock) |
1517 | static void __smq_set_clear_dirty(struct smq_policy *mq, dm_cblock_t cblock, bool set) | |
66a63635 JT |
1518 | { |
1519 | struct entry *e = get_entry(&mq->cache_alloc, from_cblock(cblock)); | |
1520 | ||
b29d4986 JT |
1521 | if (e->pending_work) |
1522 | e->dirty = set; | |
1523 | else { | |
1524 | del_queue(mq, e); | |
1525 | e->dirty = set; | |
1526 | push_queue(mq, e); | |
1527 | } | |
66a63635 JT |
1528 | } |
1529 | ||
b29d4986 | 1530 | static void smq_set_dirty(struct dm_cache_policy *p, dm_cblock_t cblock) |
66a63635 | 1531 | { |
4051aab7 | 1532 | unsigned long flags; |
66a63635 JT |
1533 | struct smq_policy *mq = to_smq_policy(p); |
1534 | ||
4051aab7 | 1535 | spin_lock_irqsave(&mq->lock, flags); |
b29d4986 | 1536 | __smq_set_clear_dirty(mq, cblock, true); |
4051aab7 | 1537 | spin_unlock_irqrestore(&mq->lock, flags); |
66a63635 JT |
1538 | } |
1539 | ||
b29d4986 | 1540 | static void smq_clear_dirty(struct dm_cache_policy *p, dm_cblock_t cblock) |
66a63635 | 1541 | { |
b29d4986 JT |
1542 | struct smq_policy *mq = to_smq_policy(p); |
1543 | unsigned long flags; | |
66a63635 | 1544 | |
b29d4986 JT |
1545 | spin_lock_irqsave(&mq->lock, flags); |
1546 | __smq_set_clear_dirty(mq, cblock, false); | |
1547 | spin_unlock_irqrestore(&mq->lock, flags); | |
66a63635 JT |
1548 | } |
1549 | ||
b29d4986 | 1550 | static unsigned random_level(dm_cblock_t cblock) |
66a63635 | 1551 | { |
b29d4986 JT |
1552 | return hash_32(from_cblock(cblock), 9) & (NR_CACHE_LEVELS - 1); |
1553 | } | |
66a63635 | 1554 | |
b29d4986 JT |
1555 | static int smq_load_mapping(struct dm_cache_policy *p, |
1556 | dm_oblock_t oblock, dm_cblock_t cblock, | |
1557 | bool dirty, uint32_t hint, bool hint_valid) | |
1558 | { | |
1559 | struct smq_policy *mq = to_smq_policy(p); | |
1560 | struct entry *e; | |
66a63635 | 1561 | |
b29d4986 JT |
1562 | e = alloc_particular_entry(&mq->cache_alloc, from_cblock(cblock)); |
1563 | e->oblock = oblock; | |
1564 | e->dirty = dirty; | |
1565 | e->level = hint_valid ? min(hint, NR_CACHE_LEVELS - 1) : random_level(cblock); | |
1566 | e->pending_work = false; | |
66a63635 | 1567 | |
b29d4986 JT |
1568 | /* |
1569 | * When we load mappings we push ahead of both sentinels in order to | |
1570 | * allow demotions and cleaning to occur immediately. | |
1571 | */ | |
1572 | push_front(mq, e); | |
66a63635 JT |
1573 | |
1574 | return 0; | |
1575 | } | |
1576 | ||
b29d4986 | 1577 | static int smq_invalidate_mapping(struct dm_cache_policy *p, dm_cblock_t cblock) |
66a63635 | 1578 | { |
66a63635 | 1579 | struct smq_policy *mq = to_smq_policy(p); |
b29d4986 | 1580 | struct entry *e = get_entry(&mq->cache_alloc, from_cblock(cblock)); |
66a63635 | 1581 | |
b29d4986 JT |
1582 | if (!e->allocated) |
1583 | return -ENODATA; | |
66a63635 | 1584 | |
b29d4986 JT |
1585 | // FIXME: what if this block has pending background work? |
1586 | del_queue(mq, e); | |
1587 | h_remove(&mq->table, e); | |
1588 | free_entry(&mq->cache_alloc, e); | |
1589 | return 0; | |
66a63635 JT |
1590 | } |
1591 | ||
b29d4986 | 1592 | static uint32_t smq_get_hint(struct dm_cache_policy *p, dm_cblock_t cblock) |
66a63635 JT |
1593 | { |
1594 | struct smq_policy *mq = to_smq_policy(p); | |
b29d4986 | 1595 | struct entry *e = get_entry(&mq->cache_alloc, from_cblock(cblock)); |
66a63635 | 1596 | |
b29d4986 JT |
1597 | if (!e->allocated) |
1598 | return 0; | |
1599 | ||
1600 | return e->level; | |
66a63635 JT |
1601 | } |
1602 | ||
1603 | static dm_cblock_t smq_residency(struct dm_cache_policy *p) | |
1604 | { | |
1605 | dm_cblock_t r; | |
4051aab7 | 1606 | unsigned long flags; |
66a63635 JT |
1607 | struct smq_policy *mq = to_smq_policy(p); |
1608 | ||
4051aab7 | 1609 | spin_lock_irqsave(&mq->lock, flags); |
66a63635 | 1610 | r = to_cblock(mq->cache_alloc.nr_allocated); |
4051aab7 | 1611 | spin_unlock_irqrestore(&mq->lock, flags); |
66a63635 JT |
1612 | |
1613 | return r; | |
1614 | } | |
1615 | ||
fba10109 | 1616 | static void smq_tick(struct dm_cache_policy *p, bool can_block) |
66a63635 JT |
1617 | { |
1618 | struct smq_policy *mq = to_smq_policy(p); | |
1619 | unsigned long flags; | |
1620 | ||
4051aab7 JT |
1621 | spin_lock_irqsave(&mq->lock, flags); |
1622 | mq->tick++; | |
1623 | update_sentinels(mq); | |
1624 | end_hotspot_period(mq); | |
1625 | end_cache_period(mq); | |
1626 | spin_unlock_irqrestore(&mq->lock, flags); | |
66a63635 JT |
1627 | } |
1628 | ||
b29d4986 JT |
1629 | static void smq_allow_migrations(struct dm_cache_policy *p, bool allow) |
1630 | { | |
1631 | struct smq_policy *mq = to_smq_policy(p); | |
1632 | mq->migrations_allowed = allow; | |
1633 | } | |
1634 | ||
9ed84698 JT |
1635 | /* |
1636 | * smq has no config values, but the old mq policy did. To avoid breaking | |
1637 | * software we continue to accept these configurables for the mq policy, | |
1638 | * but they have no effect. | |
1639 | */ | |
1640 | static int mq_set_config_value(struct dm_cache_policy *p, | |
1641 | const char *key, const char *value) | |
1642 | { | |
1643 | unsigned long tmp; | |
1644 | ||
1645 | if (kstrtoul(value, 10, &tmp)) | |
1646 | return -EINVAL; | |
1647 | ||
1648 | if (!strcasecmp(key, "random_threshold") || | |
1649 | !strcasecmp(key, "sequential_threshold") || | |
1650 | !strcasecmp(key, "discard_promote_adjustment") || | |
1651 | !strcasecmp(key, "read_promote_adjustment") || | |
1652 | !strcasecmp(key, "write_promote_adjustment")) { | |
1653 | DMWARN("tunable '%s' no longer has any effect, mq policy is now an alias for smq", key); | |
1654 | return 0; | |
1655 | } | |
1656 | ||
1657 | return -EINVAL; | |
1658 | } | |
1659 | ||
1660 | static int mq_emit_config_values(struct dm_cache_policy *p, char *result, | |
1661 | unsigned maxlen, ssize_t *sz_ptr) | |
1662 | { | |
1663 | ssize_t sz = *sz_ptr; | |
1664 | ||
1665 | DMEMIT("10 random_threshold 0 " | |
1666 | "sequential_threshold 0 " | |
1667 | "discard_promote_adjustment 0 " | |
1668 | "read_promote_adjustment 0 " | |
1669 | "write_promote_adjustment 0 "); | |
1670 | ||
1671 | *sz_ptr = sz; | |
1672 | return 0; | |
1673 | } | |
1674 | ||
66a63635 | 1675 | /* Init the policy plugin interface function pointers. */ |
9ed84698 | 1676 | static void init_policy_functions(struct smq_policy *mq, bool mimic_mq) |
66a63635 JT |
1677 | { |
1678 | mq->policy.destroy = smq_destroy; | |
66a63635 | 1679 | mq->policy.lookup = smq_lookup; |
b29d4986 JT |
1680 | mq->policy.lookup_with_work = smq_lookup_with_work; |
1681 | mq->policy.get_background_work = smq_get_background_work; | |
1682 | mq->policy.complete_background_work = smq_complete_background_work; | |
66a63635 JT |
1683 | mq->policy.set_dirty = smq_set_dirty; |
1684 | mq->policy.clear_dirty = smq_clear_dirty; | |
1685 | mq->policy.load_mapping = smq_load_mapping; | |
b29d4986 | 1686 | mq->policy.invalidate_mapping = smq_invalidate_mapping; |
4e781b49 | 1687 | mq->policy.get_hint = smq_get_hint; |
66a63635 JT |
1688 | mq->policy.residency = smq_residency; |
1689 | mq->policy.tick = smq_tick; | |
b29d4986 | 1690 | mq->policy.allow_migrations = smq_allow_migrations; |
9ed84698 JT |
1691 | |
1692 | if (mimic_mq) { | |
1693 | mq->policy.set_config_value = mq_set_config_value; | |
1694 | mq->policy.emit_config_values = mq_emit_config_values; | |
1695 | } | |
66a63635 JT |
1696 | } |
1697 | ||
1698 | static bool too_many_hotspot_blocks(sector_t origin_size, | |
1699 | sector_t hotspot_block_size, | |
1700 | unsigned nr_hotspot_blocks) | |
1701 | { | |
1702 | return (hotspot_block_size * nr_hotspot_blocks) > origin_size; | |
1703 | } | |
1704 | ||
1705 | static void calc_hotspot_params(sector_t origin_size, | |
1706 | sector_t cache_block_size, | |
1707 | unsigned nr_cache_blocks, | |
1708 | sector_t *hotspot_block_size, | |
1709 | unsigned *nr_hotspot_blocks) | |
1710 | { | |
1711 | *hotspot_block_size = cache_block_size * 16u; | |
1712 | *nr_hotspot_blocks = max(nr_cache_blocks / 4u, 1024u); | |
1713 | ||
1714 | while ((*hotspot_block_size > cache_block_size) && | |
1715 | too_many_hotspot_blocks(origin_size, *hotspot_block_size, *nr_hotspot_blocks)) | |
1716 | *hotspot_block_size /= 2u; | |
1717 | } | |
1718 | ||
9ed84698 JT |
1719 | static struct dm_cache_policy *__smq_create(dm_cblock_t cache_size, |
1720 | sector_t origin_size, | |
1721 | sector_t cache_block_size, | |
b29d4986 JT |
1722 | bool mimic_mq, |
1723 | bool migrations_allowed) | |
66a63635 JT |
1724 | { |
1725 | unsigned i; | |
1726 | unsigned nr_sentinels_per_queue = 2u * NR_CACHE_LEVELS; | |
1727 | unsigned total_sentinels = 2u * nr_sentinels_per_queue; | |
1728 | struct smq_policy *mq = kzalloc(sizeof(*mq), GFP_KERNEL); | |
1729 | ||
1730 | if (!mq) | |
1731 | return NULL; | |
1732 | ||
9ed84698 | 1733 | init_policy_functions(mq, mimic_mq); |
66a63635 JT |
1734 | mq->cache_size = cache_size; |
1735 | mq->cache_block_size = cache_block_size; | |
1736 | ||
1737 | calc_hotspot_params(origin_size, cache_block_size, from_cblock(cache_size), | |
1738 | &mq->hotspot_block_size, &mq->nr_hotspot_blocks); | |
1739 | ||
1740 | mq->cache_blocks_per_hotspot_block = div64_u64(mq->hotspot_block_size, mq->cache_block_size); | |
1741 | mq->hotspot_level_jump = 1u; | |
1742 | if (space_init(&mq->es, total_sentinels + mq->nr_hotspot_blocks + from_cblock(cache_size))) { | |
1743 | DMERR("couldn't initialize entry space"); | |
1744 | goto bad_pool_init; | |
1745 | } | |
1746 | ||
1747 | init_allocator(&mq->writeback_sentinel_alloc, &mq->es, 0, nr_sentinels_per_queue); | |
b29d4986 | 1748 | for (i = 0; i < nr_sentinels_per_queue; i++) |
66a63635 JT |
1749 | get_entry(&mq->writeback_sentinel_alloc, i)->sentinel = true; |
1750 | ||
1751 | init_allocator(&mq->demote_sentinel_alloc, &mq->es, nr_sentinels_per_queue, total_sentinels); | |
b29d4986 | 1752 | for (i = 0; i < nr_sentinels_per_queue; i++) |
66a63635 JT |
1753 | get_entry(&mq->demote_sentinel_alloc, i)->sentinel = true; |
1754 | ||
1755 | init_allocator(&mq->hotspot_alloc, &mq->es, total_sentinels, | |
1756 | total_sentinels + mq->nr_hotspot_blocks); | |
1757 | ||
1758 | init_allocator(&mq->cache_alloc, &mq->es, | |
1759 | total_sentinels + mq->nr_hotspot_blocks, | |
1760 | total_sentinels + mq->nr_hotspot_blocks + from_cblock(cache_size)); | |
1761 | ||
1762 | mq->hotspot_hit_bits = alloc_bitset(mq->nr_hotspot_blocks); | |
1763 | if (!mq->hotspot_hit_bits) { | |
1764 | DMERR("couldn't allocate hotspot hit bitset"); | |
1765 | goto bad_hotspot_hit_bits; | |
1766 | } | |
1767 | clear_bitset(mq->hotspot_hit_bits, mq->nr_hotspot_blocks); | |
1768 | ||
1769 | if (from_cblock(cache_size)) { | |
1770 | mq->cache_hit_bits = alloc_bitset(from_cblock(cache_size)); | |
134bf30c | 1771 | if (!mq->cache_hit_bits) { |
66a63635 JT |
1772 | DMERR("couldn't allocate cache hit bitset"); |
1773 | goto bad_cache_hit_bits; | |
1774 | } | |
1775 | clear_bitset(mq->cache_hit_bits, from_cblock(mq->cache_size)); | |
1776 | } else | |
1777 | mq->cache_hit_bits = NULL; | |
1778 | ||
66a63635 | 1779 | mq->tick = 0; |
4051aab7 | 1780 | spin_lock_init(&mq->lock); |
66a63635 JT |
1781 | |
1782 | q_init(&mq->hotspot, &mq->es, NR_HOTSPOT_LEVELS); | |
1783 | mq->hotspot.nr_top_levels = 8; | |
1784 | mq->hotspot.nr_in_top_levels = min(mq->nr_hotspot_blocks / NR_HOTSPOT_LEVELS, | |
1785 | from_cblock(mq->cache_size) / mq->cache_blocks_per_hotspot_block); | |
1786 | ||
1787 | q_init(&mq->clean, &mq->es, NR_CACHE_LEVELS); | |
1788 | q_init(&mq->dirty, &mq->es, NR_CACHE_LEVELS); | |
1789 | ||
1790 | stats_init(&mq->hotspot_stats, NR_HOTSPOT_LEVELS); | |
1791 | stats_init(&mq->cache_stats, NR_CACHE_LEVELS); | |
1792 | ||
1793 | if (h_init(&mq->table, &mq->es, from_cblock(cache_size))) | |
1794 | goto bad_alloc_table; | |
1795 | ||
1796 | if (h_init(&mq->hotspot_table, &mq->es, mq->nr_hotspot_blocks)) | |
1797 | goto bad_alloc_hotspot_table; | |
1798 | ||
1799 | sentinels_init(mq); | |
1800 | mq->write_promote_level = mq->read_promote_level = NR_HOTSPOT_LEVELS; | |
1801 | ||
1802 | mq->next_hotspot_period = jiffies; | |
1803 | mq->next_cache_period = jiffies; | |
1804 | ||
8ee18ede | 1805 | mq->bg_work = btracker_create(4096); /* FIXME: hard coded value */ |
b29d4986 JT |
1806 | if (!mq->bg_work) |
1807 | goto bad_btracker; | |
1808 | ||
1809 | mq->migrations_allowed = migrations_allowed; | |
1810 | ||
66a63635 JT |
1811 | return &mq->policy; |
1812 | ||
b29d4986 JT |
1813 | bad_btracker: |
1814 | h_exit(&mq->hotspot_table); | |
66a63635 JT |
1815 | bad_alloc_hotspot_table: |
1816 | h_exit(&mq->table); | |
1817 | bad_alloc_table: | |
1818 | free_bitset(mq->cache_hit_bits); | |
1819 | bad_cache_hit_bits: | |
1820 | free_bitset(mq->hotspot_hit_bits); | |
1821 | bad_hotspot_hit_bits: | |
1822 | space_exit(&mq->es); | |
1823 | bad_pool_init: | |
1824 | kfree(mq); | |
1825 | ||
1826 | return NULL; | |
1827 | } | |
1828 | ||
9ed84698 JT |
1829 | static struct dm_cache_policy *smq_create(dm_cblock_t cache_size, |
1830 | sector_t origin_size, | |
1831 | sector_t cache_block_size) | |
1832 | { | |
b29d4986 | 1833 | return __smq_create(cache_size, origin_size, cache_block_size, false, true); |
9ed84698 JT |
1834 | } |
1835 | ||
1836 | static struct dm_cache_policy *mq_create(dm_cblock_t cache_size, | |
1837 | sector_t origin_size, | |
1838 | sector_t cache_block_size) | |
1839 | { | |
b29d4986 JT |
1840 | return __smq_create(cache_size, origin_size, cache_block_size, true, true); |
1841 | } | |
1842 | ||
1843 | static struct dm_cache_policy *cleaner_create(dm_cblock_t cache_size, | |
1844 | sector_t origin_size, | |
1845 | sector_t cache_block_size) | |
1846 | { | |
1847 | return __smq_create(cache_size, origin_size, cache_block_size, false, false); | |
9ed84698 JT |
1848 | } |
1849 | ||
66a63635 JT |
1850 | /*----------------------------------------------------------------*/ |
1851 | ||
1852 | static struct dm_cache_policy_type smq_policy_type = { | |
1853 | .name = "smq", | |
b29d4986 | 1854 | .version = {2, 0, 0}, |
66a63635 JT |
1855 | .hint_size = 4, |
1856 | .owner = THIS_MODULE, | |
1857 | .create = smq_create | |
1858 | }; | |
1859 | ||
9ed84698 JT |
1860 | static struct dm_cache_policy_type mq_policy_type = { |
1861 | .name = "mq", | |
b29d4986 | 1862 | .version = {2, 0, 0}, |
9ed84698 JT |
1863 | .hint_size = 4, |
1864 | .owner = THIS_MODULE, | |
1865 | .create = mq_create, | |
1866 | }; | |
1867 | ||
b29d4986 JT |
1868 | static struct dm_cache_policy_type cleaner_policy_type = { |
1869 | .name = "cleaner", | |
1870 | .version = {2, 0, 0}, | |
1871 | .hint_size = 4, | |
1872 | .owner = THIS_MODULE, | |
1873 | .create = cleaner_create, | |
1874 | }; | |
1875 | ||
bccab6a0 MS |
1876 | static struct dm_cache_policy_type default_policy_type = { |
1877 | .name = "default", | |
b29d4986 | 1878 | .version = {2, 0, 0}, |
bccab6a0 MS |
1879 | .hint_size = 4, |
1880 | .owner = THIS_MODULE, | |
1881 | .create = smq_create, | |
1882 | .real = &smq_policy_type | |
1883 | }; | |
1884 | ||
66a63635 JT |
1885 | static int __init smq_init(void) |
1886 | { | |
1887 | int r; | |
1888 | ||
1889 | r = dm_cache_policy_register(&smq_policy_type); | |
1890 | if (r) { | |
1891 | DMERR("register failed %d", r); | |
1892 | return -ENOMEM; | |
1893 | } | |
1894 | ||
9ed84698 JT |
1895 | r = dm_cache_policy_register(&mq_policy_type); |
1896 | if (r) { | |
7dd85bb0 | 1897 | DMERR("register failed (as mq) %d", r); |
b29d4986 JT |
1898 | goto out_mq; |
1899 | } | |
1900 | ||
1901 | r = dm_cache_policy_register(&cleaner_policy_type); | |
1902 | if (r) { | |
1903 | DMERR("register failed (as cleaner) %d", r); | |
1904 | goto out_cleaner; | |
9ed84698 JT |
1905 | } |
1906 | ||
bccab6a0 MS |
1907 | r = dm_cache_policy_register(&default_policy_type); |
1908 | if (r) { | |
1909 | DMERR("register failed (as default) %d", r); | |
b29d4986 | 1910 | goto out_default; |
bccab6a0 MS |
1911 | } |
1912 | ||
66a63635 | 1913 | return 0; |
b29d4986 JT |
1914 | |
1915 | out_default: | |
1916 | dm_cache_policy_unregister(&cleaner_policy_type); | |
1917 | out_cleaner: | |
1918 | dm_cache_policy_unregister(&mq_policy_type); | |
1919 | out_mq: | |
1920 | dm_cache_policy_unregister(&smq_policy_type); | |
1921 | ||
1922 | return -ENOMEM; | |
66a63635 JT |
1923 | } |
1924 | ||
1925 | static void __exit smq_exit(void) | |
1926 | { | |
b29d4986 | 1927 | dm_cache_policy_unregister(&cleaner_policy_type); |
66a63635 | 1928 | dm_cache_policy_unregister(&smq_policy_type); |
9ed84698 | 1929 | dm_cache_policy_unregister(&mq_policy_type); |
bccab6a0 | 1930 | dm_cache_policy_unregister(&default_policy_type); |
66a63635 JT |
1931 | } |
1932 | ||
1933 | module_init(smq_init); | |
1934 | module_exit(smq_exit); | |
1935 | ||
1936 | MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); | |
1937 | MODULE_LICENSE("GPL"); | |
1938 | MODULE_DESCRIPTION("smq cache policy"); | |
34dd0517 YZ |
1939 | |
1940 | MODULE_ALIAS("dm-cache-default"); | |
9ed84698 | 1941 | MODULE_ALIAS("dm-cache-mq"); |
b29d4986 | 1942 | MODULE_ALIAS("dm-cache-cleaner"); |