Commit | Line | Data |
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0fc479b1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
88459642 OS |
2 | /* |
3 | * Copyright (C) 2016 Facebook | |
4 | * Copyright (C) 2013-2014 Jens Axboe | |
88459642 OS |
5 | */ |
6 | ||
af8601ad | 7 | #include <linux/sched.h> |
98d95416 | 8 | #include <linux/random.h> |
88459642 | 9 | #include <linux/sbitmap.h> |
24af1ccf | 10 | #include <linux/seq_file.h> |
88459642 | 11 | |
c548e62b | 12 | static int init_alloc_hint(struct sbitmap *sb, gfp_t flags) |
bf2c4282 | 13 | { |
c548e62b | 14 | unsigned depth = sb->depth; |
bf2c4282 | 15 | |
c548e62b ML |
16 | sb->alloc_hint = alloc_percpu_gfp(unsigned int, flags); |
17 | if (!sb->alloc_hint) | |
bf2c4282 ML |
18 | return -ENOMEM; |
19 | ||
c548e62b | 20 | if (depth && !sb->round_robin) { |
bf2c4282 ML |
21 | int i; |
22 | ||
23 | for_each_possible_cpu(i) | |
c548e62b | 24 | *per_cpu_ptr(sb->alloc_hint, i) = prandom_u32() % depth; |
bf2c4282 | 25 | } |
bf2c4282 ML |
26 | return 0; |
27 | } | |
28 | ||
c548e62b | 29 | static inline unsigned update_alloc_hint_before_get(struct sbitmap *sb, |
bf2c4282 ML |
30 | unsigned int depth) |
31 | { | |
32 | unsigned hint; | |
33 | ||
c548e62b | 34 | hint = this_cpu_read(*sb->alloc_hint); |
bf2c4282 ML |
35 | if (unlikely(hint >= depth)) { |
36 | hint = depth ? prandom_u32() % depth : 0; | |
c548e62b | 37 | this_cpu_write(*sb->alloc_hint, hint); |
bf2c4282 ML |
38 | } |
39 | ||
40 | return hint; | |
41 | } | |
42 | ||
c548e62b | 43 | static inline void update_alloc_hint_after_get(struct sbitmap *sb, |
bf2c4282 ML |
44 | unsigned int depth, |
45 | unsigned int hint, | |
46 | unsigned int nr) | |
47 | { | |
48 | if (nr == -1) { | |
49 | /* If the map is full, a hint won't do us much good. */ | |
c548e62b ML |
50 | this_cpu_write(*sb->alloc_hint, 0); |
51 | } else if (nr == hint || unlikely(sb->round_robin)) { | |
bf2c4282 ML |
52 | /* Only update the hint if we used it. */ |
53 | hint = nr + 1; | |
54 | if (hint >= depth - 1) | |
55 | hint = 0; | |
c548e62b | 56 | this_cpu_write(*sb->alloc_hint, hint); |
bf2c4282 ML |
57 | } |
58 | } | |
59 | ||
b2dbff1b JA |
60 | /* |
61 | * See if we have deferred clears that we can batch move | |
62 | */ | |
b78beea0 | 63 | static inline bool sbitmap_deferred_clear(struct sbitmap_word *map) |
b2dbff1b | 64 | { |
c3250c8d | 65 | unsigned long mask; |
b2dbff1b | 66 | |
661d4f55 PB |
67 | if (!READ_ONCE(map->cleared)) |
68 | return false; | |
b2dbff1b JA |
69 | |
70 | /* | |
71 | * First get a stable cleared mask, setting the old mask to 0. | |
72 | */ | |
b78beea0 | 73 | mask = xchg(&map->cleared, 0); |
b2dbff1b JA |
74 | |
75 | /* | |
76 | * Now clear the masked bits in our free word | |
77 | */ | |
c3250c8d PB |
78 | atomic_long_andnot(mask, (atomic_long_t *)&map->word); |
79 | BUILD_BUG_ON(sizeof(atomic_long_t) != sizeof(map->word)); | |
661d4f55 | 80 | return true; |
b2dbff1b JA |
81 | } |
82 | ||
88459642 | 83 | int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift, |
c548e62b ML |
84 | gfp_t flags, int node, bool round_robin, |
85 | bool alloc_hint) | |
88459642 OS |
86 | { |
87 | unsigned int bits_per_word; | |
88 | unsigned int i; | |
89 | ||
90 | if (shift < 0) { | |
91 | shift = ilog2(BITS_PER_LONG); | |
92 | /* | |
93 | * If the bitmap is small, shrink the number of bits per word so | |
94 | * we spread over a few cachelines, at least. If less than 4 | |
95 | * bits, just forget about it, it's not going to work optimally | |
96 | * anyway. | |
97 | */ | |
98 | if (depth >= 4) { | |
99 | while ((4U << shift) > depth) | |
100 | shift--; | |
101 | } | |
102 | } | |
103 | bits_per_word = 1U << shift; | |
104 | if (bits_per_word > BITS_PER_LONG) | |
105 | return -EINVAL; | |
106 | ||
107 | sb->shift = shift; | |
108 | sb->depth = depth; | |
109 | sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word); | |
efe1f3a1 | 110 | sb->round_robin = round_robin; |
88459642 OS |
111 | |
112 | if (depth == 0) { | |
113 | sb->map = NULL; | |
114 | return 0; | |
115 | } | |
116 | ||
c548e62b ML |
117 | if (alloc_hint) { |
118 | if (init_alloc_hint(sb, flags)) | |
119 | return -ENOMEM; | |
120 | } else { | |
121 | sb->alloc_hint = NULL; | |
122 | } | |
123 | ||
590b5b7d | 124 | sb->map = kcalloc_node(sb->map_nr, sizeof(*sb->map), flags, node); |
c548e62b ML |
125 | if (!sb->map) { |
126 | free_percpu(sb->alloc_hint); | |
88459642 | 127 | return -ENOMEM; |
c548e62b | 128 | } |
88459642 OS |
129 | |
130 | for (i = 0; i < sb->map_nr; i++) { | |
131 | sb->map[i].depth = min(depth, bits_per_word); | |
132 | depth -= sb->map[i].depth; | |
133 | } | |
134 | return 0; | |
135 | } | |
136 | EXPORT_SYMBOL_GPL(sbitmap_init_node); | |
137 | ||
138 | void sbitmap_resize(struct sbitmap *sb, unsigned int depth) | |
139 | { | |
140 | unsigned int bits_per_word = 1U << sb->shift; | |
141 | unsigned int i; | |
142 | ||
b2dbff1b | 143 | for (i = 0; i < sb->map_nr; i++) |
b78beea0 | 144 | sbitmap_deferred_clear(&sb->map[i]); |
b2dbff1b | 145 | |
88459642 OS |
146 | sb->depth = depth; |
147 | sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word); | |
148 | ||
149 | for (i = 0; i < sb->map_nr; i++) { | |
150 | sb->map[i].depth = min(depth, bits_per_word); | |
151 | depth -= sb->map[i].depth; | |
152 | } | |
153 | } | |
154 | EXPORT_SYMBOL_GPL(sbitmap_resize); | |
155 | ||
c05e6673 OS |
156 | static int __sbitmap_get_word(unsigned long *word, unsigned long depth, |
157 | unsigned int hint, bool wrap) | |
88459642 | 158 | { |
88459642 OS |
159 | int nr; |
160 | ||
0eff1f1a PB |
161 | /* don't wrap if starting from 0 */ |
162 | wrap = wrap && hint; | |
163 | ||
88459642 | 164 | while (1) { |
c05e6673 OS |
165 | nr = find_next_zero_bit(word, depth, hint); |
166 | if (unlikely(nr >= depth)) { | |
88459642 OS |
167 | /* |
168 | * We started with an offset, and we didn't reset the | |
169 | * offset to 0 in a failure case, so start from 0 to | |
170 | * exhaust the map. | |
171 | */ | |
0eff1f1a PB |
172 | if (hint && wrap) { |
173 | hint = 0; | |
88459642 OS |
174 | continue; |
175 | } | |
176 | return -1; | |
177 | } | |
178 | ||
4ace53f1 | 179 | if (!test_and_set_bit_lock(nr, word)) |
88459642 OS |
180 | break; |
181 | ||
182 | hint = nr + 1; | |
c05e6673 | 183 | if (hint >= depth - 1) |
88459642 OS |
184 | hint = 0; |
185 | } | |
186 | ||
187 | return nr; | |
188 | } | |
189 | ||
ea86ea2c | 190 | static int sbitmap_find_bit_in_index(struct sbitmap *sb, int index, |
efe1f3a1 | 191 | unsigned int alloc_hint) |
ea86ea2c | 192 | { |
b78beea0 | 193 | struct sbitmap_word *map = &sb->map[index]; |
ea86ea2c JA |
194 | int nr; |
195 | ||
196 | do { | |
b78beea0 | 197 | nr = __sbitmap_get_word(&map->word, map->depth, alloc_hint, |
efe1f3a1 | 198 | !sb->round_robin); |
ea86ea2c JA |
199 | if (nr != -1) |
200 | break; | |
b78beea0 | 201 | if (!sbitmap_deferred_clear(map)) |
ea86ea2c JA |
202 | break; |
203 | } while (1); | |
204 | ||
205 | return nr; | |
206 | } | |
207 | ||
c548e62b | 208 | static int __sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint) |
88459642 OS |
209 | { |
210 | unsigned int i, index; | |
211 | int nr = -1; | |
212 | ||
213 | index = SB_NR_TO_INDEX(sb, alloc_hint); | |
214 | ||
27fae429 JA |
215 | /* |
216 | * Unless we're doing round robin tag allocation, just use the | |
217 | * alloc_hint to find the right word index. No point in looping | |
218 | * twice in find_next_zero_bit() for that case. | |
219 | */ | |
efe1f3a1 | 220 | if (sb->round_robin) |
27fae429 JA |
221 | alloc_hint = SB_NR_TO_BIT(sb, alloc_hint); |
222 | else | |
223 | alloc_hint = 0; | |
224 | ||
88459642 | 225 | for (i = 0; i < sb->map_nr; i++) { |
efe1f3a1 | 226 | nr = sbitmap_find_bit_in_index(sb, index, alloc_hint); |
88459642 OS |
227 | if (nr != -1) { |
228 | nr += index << sb->shift; | |
229 | break; | |
230 | } | |
231 | ||
232 | /* Jump to next index. */ | |
27fae429 JA |
233 | alloc_hint = 0; |
234 | if (++index >= sb->map_nr) | |
88459642 | 235 | index = 0; |
88459642 OS |
236 | } |
237 | ||
238 | return nr; | |
239 | } | |
c548e62b ML |
240 | |
241 | int sbitmap_get(struct sbitmap *sb) | |
242 | { | |
243 | int nr; | |
244 | unsigned int hint, depth; | |
245 | ||
246 | if (WARN_ON_ONCE(unlikely(!sb->alloc_hint))) | |
247 | return -1; | |
248 | ||
249 | depth = READ_ONCE(sb->depth); | |
250 | hint = update_alloc_hint_before_get(sb, depth); | |
251 | nr = __sbitmap_get(sb, hint); | |
252 | update_alloc_hint_after_get(sb, depth, hint, nr); | |
253 | ||
254 | return nr; | |
255 | } | |
88459642 OS |
256 | EXPORT_SYMBOL_GPL(sbitmap_get); |
257 | ||
c548e62b ML |
258 | static int __sbitmap_get_shallow(struct sbitmap *sb, |
259 | unsigned int alloc_hint, | |
260 | unsigned long shallow_depth) | |
c05e6673 OS |
261 | { |
262 | unsigned int i, index; | |
263 | int nr = -1; | |
264 | ||
265 | index = SB_NR_TO_INDEX(sb, alloc_hint); | |
266 | ||
267 | for (i = 0; i < sb->map_nr; i++) { | |
b2dbff1b | 268 | again: |
c05e6673 OS |
269 | nr = __sbitmap_get_word(&sb->map[index].word, |
270 | min(sb->map[index].depth, shallow_depth), | |
271 | SB_NR_TO_BIT(sb, alloc_hint), true); | |
272 | if (nr != -1) { | |
273 | nr += index << sb->shift; | |
274 | break; | |
275 | } | |
276 | ||
b78beea0 | 277 | if (sbitmap_deferred_clear(&sb->map[index])) |
b2dbff1b JA |
278 | goto again; |
279 | ||
c05e6673 OS |
280 | /* Jump to next index. */ |
281 | index++; | |
282 | alloc_hint = index << sb->shift; | |
283 | ||
284 | if (index >= sb->map_nr) { | |
285 | index = 0; | |
286 | alloc_hint = 0; | |
287 | } | |
288 | } | |
289 | ||
290 | return nr; | |
291 | } | |
c548e62b ML |
292 | |
293 | int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth) | |
294 | { | |
295 | int nr; | |
296 | unsigned int hint, depth; | |
297 | ||
298 | if (WARN_ON_ONCE(unlikely(!sb->alloc_hint))) | |
299 | return -1; | |
300 | ||
301 | depth = READ_ONCE(sb->depth); | |
302 | hint = update_alloc_hint_before_get(sb, depth); | |
303 | nr = __sbitmap_get_shallow(sb, hint, shallow_depth); | |
304 | update_alloc_hint_after_get(sb, depth, hint, nr); | |
305 | ||
306 | return nr; | |
307 | } | |
c05e6673 OS |
308 | EXPORT_SYMBOL_GPL(sbitmap_get_shallow); |
309 | ||
88459642 OS |
310 | bool sbitmap_any_bit_set(const struct sbitmap *sb) |
311 | { | |
312 | unsigned int i; | |
313 | ||
314 | for (i = 0; i < sb->map_nr; i++) { | |
b2dbff1b | 315 | if (sb->map[i].word & ~sb->map[i].cleared) |
88459642 OS |
316 | return true; |
317 | } | |
318 | return false; | |
319 | } | |
320 | EXPORT_SYMBOL_GPL(sbitmap_any_bit_set); | |
321 | ||
ea86ea2c | 322 | static unsigned int __sbitmap_weight(const struct sbitmap *sb, bool set) |
88459642 | 323 | { |
60658e0d | 324 | unsigned int i, weight = 0; |
88459642 OS |
325 | |
326 | for (i = 0; i < sb->map_nr; i++) { | |
327 | const struct sbitmap_word *word = &sb->map[i]; | |
328 | ||
ea86ea2c JA |
329 | if (set) |
330 | weight += bitmap_weight(&word->word, word->depth); | |
331 | else | |
332 | weight += bitmap_weight(&word->cleared, word->depth); | |
88459642 OS |
333 | } |
334 | return weight; | |
335 | } | |
ea86ea2c JA |
336 | |
337 | static unsigned int sbitmap_weight(const struct sbitmap *sb) | |
338 | { | |
339 | return __sbitmap_weight(sb, true); | |
340 | } | |
341 | ||
342 | static unsigned int sbitmap_cleared(const struct sbitmap *sb) | |
343 | { | |
344 | return __sbitmap_weight(sb, false); | |
345 | } | |
88459642 | 346 | |
24af1ccf OS |
347 | void sbitmap_show(struct sbitmap *sb, struct seq_file *m) |
348 | { | |
349 | seq_printf(m, "depth=%u\n", sb->depth); | |
ea86ea2c JA |
350 | seq_printf(m, "busy=%u\n", sbitmap_weight(sb) - sbitmap_cleared(sb)); |
351 | seq_printf(m, "cleared=%u\n", sbitmap_cleared(sb)); | |
24af1ccf OS |
352 | seq_printf(m, "bits_per_word=%u\n", 1U << sb->shift); |
353 | seq_printf(m, "map_nr=%u\n", sb->map_nr); | |
354 | } | |
355 | EXPORT_SYMBOL_GPL(sbitmap_show); | |
356 | ||
357 | static inline void emit_byte(struct seq_file *m, unsigned int offset, u8 byte) | |
358 | { | |
359 | if ((offset & 0xf) == 0) { | |
360 | if (offset != 0) | |
361 | seq_putc(m, '\n'); | |
362 | seq_printf(m, "%08x:", offset); | |
363 | } | |
364 | if ((offset & 0x1) == 0) | |
365 | seq_putc(m, ' '); | |
366 | seq_printf(m, "%02x", byte); | |
367 | } | |
368 | ||
369 | void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m) | |
370 | { | |
371 | u8 byte = 0; | |
372 | unsigned int byte_bits = 0; | |
373 | unsigned int offset = 0; | |
374 | int i; | |
375 | ||
376 | for (i = 0; i < sb->map_nr; i++) { | |
377 | unsigned long word = READ_ONCE(sb->map[i].word); | |
6bf0eb55 | 378 | unsigned long cleared = READ_ONCE(sb->map[i].cleared); |
24af1ccf OS |
379 | unsigned int word_bits = READ_ONCE(sb->map[i].depth); |
380 | ||
6bf0eb55 JG |
381 | word &= ~cleared; |
382 | ||
24af1ccf OS |
383 | while (word_bits > 0) { |
384 | unsigned int bits = min(8 - byte_bits, word_bits); | |
385 | ||
386 | byte |= (word & (BIT(bits) - 1)) << byte_bits; | |
387 | byte_bits += bits; | |
388 | if (byte_bits == 8) { | |
389 | emit_byte(m, offset, byte); | |
390 | byte = 0; | |
391 | byte_bits = 0; | |
392 | offset++; | |
393 | } | |
394 | word >>= bits; | |
395 | word_bits -= bits; | |
396 | } | |
397 | } | |
398 | if (byte_bits) { | |
399 | emit_byte(m, offset, byte); | |
400 | offset++; | |
401 | } | |
402 | if (offset) | |
403 | seq_putc(m, '\n'); | |
404 | } | |
405 | EXPORT_SYMBOL_GPL(sbitmap_bitmap_show); | |
406 | ||
a3275539 OS |
407 | static unsigned int sbq_calc_wake_batch(struct sbitmap_queue *sbq, |
408 | unsigned int depth) | |
88459642 OS |
409 | { |
410 | unsigned int wake_batch; | |
a3275539 | 411 | unsigned int shallow_depth; |
88459642 OS |
412 | |
413 | /* | |
414 | * For each batch, we wake up one queue. We need to make sure that our | |
a3275539 OS |
415 | * batch size is small enough that the full depth of the bitmap, |
416 | * potentially limited by a shallow depth, is enough to wake up all of | |
417 | * the queues. | |
418 | * | |
419 | * Each full word of the bitmap has bits_per_word bits, and there might | |
420 | * be a partial word. There are depth / bits_per_word full words and | |
421 | * depth % bits_per_word bits left over. In bitwise arithmetic: | |
422 | * | |
423 | * bits_per_word = 1 << shift | |
424 | * depth / bits_per_word = depth >> shift | |
425 | * depth % bits_per_word = depth & ((1 << shift) - 1) | |
426 | * | |
427 | * Each word can be limited to sbq->min_shallow_depth bits. | |
88459642 | 428 | */ |
a3275539 OS |
429 | shallow_depth = min(1U << sbq->sb.shift, sbq->min_shallow_depth); |
430 | depth = ((depth >> sbq->sb.shift) * shallow_depth + | |
431 | min(depth & ((1U << sbq->sb.shift) - 1), shallow_depth)); | |
432 | wake_batch = clamp_t(unsigned int, depth / SBQ_WAIT_QUEUES, 1, | |
433 | SBQ_WAKE_BATCH); | |
88459642 OS |
434 | |
435 | return wake_batch; | |
436 | } | |
437 | ||
438 | int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth, | |
f4a644db | 439 | int shift, bool round_robin, gfp_t flags, int node) |
88459642 OS |
440 | { |
441 | int ret; | |
442 | int i; | |
443 | ||
efe1f3a1 | 444 | ret = sbitmap_init_node(&sbq->sb, depth, shift, flags, node, |
c548e62b | 445 | round_robin, true); |
88459642 OS |
446 | if (ret) |
447 | return ret; | |
448 | ||
a3275539 OS |
449 | sbq->min_shallow_depth = UINT_MAX; |
450 | sbq->wake_batch = sbq_calc_wake_batch(sbq, depth); | |
88459642 | 451 | atomic_set(&sbq->wake_index, 0); |
5d2ee712 | 452 | atomic_set(&sbq->ws_active, 0); |
88459642 | 453 | |
48e28166 | 454 | sbq->ws = kzalloc_node(SBQ_WAIT_QUEUES * sizeof(*sbq->ws), flags, node); |
88459642 OS |
455 | if (!sbq->ws) { |
456 | sbitmap_free(&sbq->sb); | |
457 | return -ENOMEM; | |
458 | } | |
459 | ||
460 | for (i = 0; i < SBQ_WAIT_QUEUES; i++) { | |
461 | init_waitqueue_head(&sbq->ws[i].wait); | |
462 | atomic_set(&sbq->ws[i].wait_cnt, sbq->wake_batch); | |
463 | } | |
f4a644db | 464 | |
88459642 OS |
465 | return 0; |
466 | } | |
467 | EXPORT_SYMBOL_GPL(sbitmap_queue_init_node); | |
468 | ||
a3275539 OS |
469 | static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq, |
470 | unsigned int depth) | |
88459642 | 471 | { |
a3275539 | 472 | unsigned int wake_batch = sbq_calc_wake_batch(sbq, depth); |
6c0ca7ae OS |
473 | int i; |
474 | ||
475 | if (sbq->wake_batch != wake_batch) { | |
476 | WRITE_ONCE(sbq->wake_batch, wake_batch); | |
477 | /* | |
e6fc4649 ML |
478 | * Pairs with the memory barrier in sbitmap_queue_wake_up() |
479 | * to ensure that the batch size is updated before the wait | |
480 | * counts. | |
6c0ca7ae | 481 | */ |
a0934fd2 | 482 | smp_mb(); |
6c0ca7ae OS |
483 | for (i = 0; i < SBQ_WAIT_QUEUES; i++) |
484 | atomic_set(&sbq->ws[i].wait_cnt, 1); | |
485 | } | |
a3275539 OS |
486 | } |
487 | ||
488 | void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth) | |
489 | { | |
490 | sbitmap_queue_update_wake_batch(sbq, depth); | |
88459642 OS |
491 | sbitmap_resize(&sbq->sb, depth); |
492 | } | |
493 | EXPORT_SYMBOL_GPL(sbitmap_queue_resize); | |
494 | ||
f4a644db | 495 | int __sbitmap_queue_get(struct sbitmap_queue *sbq) |
40aabb67 | 496 | { |
c548e62b | 497 | return sbitmap_get(&sbq->sb); |
40aabb67 OS |
498 | } |
499 | EXPORT_SYMBOL_GPL(__sbitmap_queue_get); | |
500 | ||
c05e6673 OS |
501 | int __sbitmap_queue_get_shallow(struct sbitmap_queue *sbq, |
502 | unsigned int shallow_depth) | |
503 | { | |
61445b56 OS |
504 | WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth); |
505 | ||
c548e62b | 506 | return sbitmap_get_shallow(&sbq->sb, shallow_depth); |
c05e6673 OS |
507 | } |
508 | EXPORT_SYMBOL_GPL(__sbitmap_queue_get_shallow); | |
509 | ||
a3275539 OS |
510 | void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq, |
511 | unsigned int min_shallow_depth) | |
512 | { | |
513 | sbq->min_shallow_depth = min_shallow_depth; | |
514 | sbitmap_queue_update_wake_batch(sbq, sbq->sb.depth); | |
515 | } | |
516 | EXPORT_SYMBOL_GPL(sbitmap_queue_min_shallow_depth); | |
517 | ||
88459642 OS |
518 | static struct sbq_wait_state *sbq_wake_ptr(struct sbitmap_queue *sbq) |
519 | { | |
520 | int i, wake_index; | |
521 | ||
5d2ee712 JA |
522 | if (!atomic_read(&sbq->ws_active)) |
523 | return NULL; | |
524 | ||
88459642 OS |
525 | wake_index = atomic_read(&sbq->wake_index); |
526 | for (i = 0; i < SBQ_WAIT_QUEUES; i++) { | |
527 | struct sbq_wait_state *ws = &sbq->ws[wake_index]; | |
528 | ||
529 | if (waitqueue_active(&ws->wait)) { | |
41723288 PB |
530 | if (wake_index != atomic_read(&sbq->wake_index)) |
531 | atomic_set(&sbq->wake_index, wake_index); | |
88459642 OS |
532 | return ws; |
533 | } | |
534 | ||
535 | wake_index = sbq_index_inc(wake_index); | |
536 | } | |
537 | ||
538 | return NULL; | |
539 | } | |
540 | ||
c854ab57 | 541 | static bool __sbq_wake_up(struct sbitmap_queue *sbq) |
88459642 OS |
542 | { |
543 | struct sbq_wait_state *ws; | |
6c0ca7ae | 544 | unsigned int wake_batch; |
88459642 OS |
545 | int wait_cnt; |
546 | ||
88459642 OS |
547 | ws = sbq_wake_ptr(sbq); |
548 | if (!ws) | |
c854ab57 | 549 | return false; |
88459642 OS |
550 | |
551 | wait_cnt = atomic_dec_return(&ws->wait_cnt); | |
6c0ca7ae | 552 | if (wait_cnt <= 0) { |
c854ab57 JA |
553 | int ret; |
554 | ||
6c0ca7ae | 555 | wake_batch = READ_ONCE(sbq->wake_batch); |
c854ab57 | 556 | |
6c0ca7ae OS |
557 | /* |
558 | * Pairs with the memory barrier in sbitmap_queue_resize() to | |
559 | * ensure that we see the batch size update before the wait | |
560 | * count is reset. | |
561 | */ | |
562 | smp_mb__before_atomic(); | |
c854ab57 | 563 | |
6c0ca7ae | 564 | /* |
c854ab57 JA |
565 | * For concurrent callers of this, the one that failed the |
566 | * atomic_cmpxhcg() race should call this function again | |
567 | * to wakeup a new batch on a different 'ws'. | |
6c0ca7ae | 568 | */ |
c854ab57 JA |
569 | ret = atomic_cmpxchg(&ws->wait_cnt, wait_cnt, wake_batch); |
570 | if (ret == wait_cnt) { | |
571 | sbq_index_atomic_inc(&sbq->wake_index); | |
572 | wake_up_nr(&ws->wait, wake_batch); | |
573 | return false; | |
574 | } | |
575 | ||
576 | return true; | |
88459642 | 577 | } |
c854ab57 JA |
578 | |
579 | return false; | |
580 | } | |
581 | ||
e6fc4649 | 582 | void sbitmap_queue_wake_up(struct sbitmap_queue *sbq) |
c854ab57 JA |
583 | { |
584 | while (__sbq_wake_up(sbq)) | |
585 | ; | |
88459642 | 586 | } |
e6fc4649 | 587 | EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up); |
88459642 | 588 | |
40aabb67 | 589 | void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr, |
f4a644db | 590 | unsigned int cpu) |
88459642 | 591 | { |
e6d1fa58 ML |
592 | /* |
593 | * Once the clear bit is set, the bit may be allocated out. | |
594 | * | |
595 | * Orders READ/WRITE on the asssociated instance(such as request | |
596 | * of blk_mq) by this bit for avoiding race with re-allocation, | |
597 | * and its pair is the memory barrier implied in __sbitmap_get_word. | |
598 | * | |
599 | * One invariant is that the clear bit has to be zero when the bit | |
600 | * is in use. | |
601 | */ | |
602 | smp_mb__before_atomic(); | |
ea86ea2c JA |
603 | sbitmap_deferred_clear_bit(&sbq->sb, nr); |
604 | ||
e6fc4649 ML |
605 | /* |
606 | * Pairs with the memory barrier in set_current_state() to ensure the | |
607 | * proper ordering of clear_bit_unlock()/waitqueue_active() in the waker | |
608 | * and test_and_set_bit_lock()/prepare_to_wait()/finish_wait() in the | |
609 | * waiter. See the comment on waitqueue_active(). | |
610 | */ | |
611 | smp_mb__after_atomic(); | |
612 | sbitmap_queue_wake_up(sbq); | |
613 | ||
efe1f3a1 | 614 | if (likely(!sbq->sb.round_robin && nr < sbq->sb.depth)) |
c548e62b | 615 | *per_cpu_ptr(sbq->sb.alloc_hint, cpu) = nr; |
88459642 OS |
616 | } |
617 | EXPORT_SYMBOL_GPL(sbitmap_queue_clear); | |
618 | ||
619 | void sbitmap_queue_wake_all(struct sbitmap_queue *sbq) | |
620 | { | |
621 | int i, wake_index; | |
622 | ||
623 | /* | |
f66227de | 624 | * Pairs with the memory barrier in set_current_state() like in |
e6fc4649 | 625 | * sbitmap_queue_wake_up(). |
88459642 OS |
626 | */ |
627 | smp_mb(); | |
628 | wake_index = atomic_read(&sbq->wake_index); | |
629 | for (i = 0; i < SBQ_WAIT_QUEUES; i++) { | |
630 | struct sbq_wait_state *ws = &sbq->ws[wake_index]; | |
631 | ||
632 | if (waitqueue_active(&ws->wait)) | |
633 | wake_up(&ws->wait); | |
634 | ||
635 | wake_index = sbq_index_inc(wake_index); | |
636 | } | |
637 | } | |
638 | EXPORT_SYMBOL_GPL(sbitmap_queue_wake_all); | |
24af1ccf OS |
639 | |
640 | void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m) | |
641 | { | |
642 | bool first; | |
643 | int i; | |
644 | ||
645 | sbitmap_show(&sbq->sb, m); | |
646 | ||
647 | seq_puts(m, "alloc_hint={"); | |
648 | first = true; | |
649 | for_each_possible_cpu(i) { | |
650 | if (!first) | |
651 | seq_puts(m, ", "); | |
652 | first = false; | |
c548e62b | 653 | seq_printf(m, "%u", *per_cpu_ptr(sbq->sb.alloc_hint, i)); |
24af1ccf OS |
654 | } |
655 | seq_puts(m, "}\n"); | |
656 | ||
657 | seq_printf(m, "wake_batch=%u\n", sbq->wake_batch); | |
658 | seq_printf(m, "wake_index=%d\n", atomic_read(&sbq->wake_index)); | |
5d2ee712 | 659 | seq_printf(m, "ws_active=%d\n", atomic_read(&sbq->ws_active)); |
24af1ccf OS |
660 | |
661 | seq_puts(m, "ws={\n"); | |
662 | for (i = 0; i < SBQ_WAIT_QUEUES; i++) { | |
663 | struct sbq_wait_state *ws = &sbq->ws[i]; | |
664 | ||
665 | seq_printf(m, "\t{.wait_cnt=%d, .wait=%s},\n", | |
666 | atomic_read(&ws->wait_cnt), | |
667 | waitqueue_active(&ws->wait) ? "active" : "inactive"); | |
668 | } | |
669 | seq_puts(m, "}\n"); | |
670 | ||
efe1f3a1 | 671 | seq_printf(m, "round_robin=%d\n", sbq->sb.round_robin); |
a3275539 | 672 | seq_printf(m, "min_shallow_depth=%u\n", sbq->min_shallow_depth); |
24af1ccf OS |
673 | } |
674 | EXPORT_SYMBOL_GPL(sbitmap_queue_show); | |
5d2ee712 | 675 | |
9f6b7ef6 JA |
676 | void sbitmap_add_wait_queue(struct sbitmap_queue *sbq, |
677 | struct sbq_wait_state *ws, | |
678 | struct sbq_wait *sbq_wait) | |
679 | { | |
680 | if (!sbq_wait->sbq) { | |
681 | sbq_wait->sbq = sbq; | |
682 | atomic_inc(&sbq->ws_active); | |
df034c93 | 683 | add_wait_queue(&ws->wait, &sbq_wait->wait); |
9f6b7ef6 | 684 | } |
9f6b7ef6 JA |
685 | } |
686 | EXPORT_SYMBOL_GPL(sbitmap_add_wait_queue); | |
687 | ||
688 | void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait) | |
689 | { | |
690 | list_del_init(&sbq_wait->wait.entry); | |
691 | if (sbq_wait->sbq) { | |
692 | atomic_dec(&sbq_wait->sbq->ws_active); | |
693 | sbq_wait->sbq = NULL; | |
694 | } | |
695 | } | |
696 | EXPORT_SYMBOL_GPL(sbitmap_del_wait_queue); | |
697 | ||
5d2ee712 JA |
698 | void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq, |
699 | struct sbq_wait_state *ws, | |
700 | struct sbq_wait *sbq_wait, int state) | |
701 | { | |
9f6b7ef6 | 702 | if (!sbq_wait->sbq) { |
5d2ee712 | 703 | atomic_inc(&sbq->ws_active); |
9f6b7ef6 | 704 | sbq_wait->sbq = sbq; |
5d2ee712 JA |
705 | } |
706 | prepare_to_wait_exclusive(&ws->wait, &sbq_wait->wait, state); | |
707 | } | |
708 | EXPORT_SYMBOL_GPL(sbitmap_prepare_to_wait); | |
709 | ||
710 | void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws, | |
711 | struct sbq_wait *sbq_wait) | |
712 | { | |
713 | finish_wait(&ws->wait, &sbq_wait->wait); | |
9f6b7ef6 | 714 | if (sbq_wait->sbq) { |
5d2ee712 | 715 | atomic_dec(&sbq->ws_active); |
9f6b7ef6 | 716 | sbq_wait->sbq = NULL; |
5d2ee712 JA |
717 | } |
718 | } | |
719 | EXPORT_SYMBOL_GPL(sbitmap_finish_wait); |