Commit | Line | Data |
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0fc479b1 | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
88459642 OS |
2 | /* |
3 | * Fast and scalable bitmaps. | |
4 | * | |
5 | * Copyright (C) 2016 Facebook | |
6 | * Copyright (C) 2013-2014 Jens Axboe | |
88459642 OS |
7 | */ |
8 | ||
9 | #ifndef __LINUX_SCALE_BITMAP_H | |
10 | #define __LINUX_SCALE_BITMAP_H | |
11 | ||
1fcbd5de AS |
12 | #include <linux/atomic.h> |
13 | #include <linux/bitops.h> | |
14 | #include <linux/cache.h> | |
15 | #include <linux/list.h> | |
16 | #include <linux/log2.h> | |
17 | #include <linux/minmax.h> | |
18 | #include <linux/percpu.h> | |
88459642 | 19 | #include <linux/slab.h> |
1fcbd5de AS |
20 | #include <linux/smp.h> |
21 | #include <linux/types.h> | |
22 | #include <linux/wait.h> | |
88459642 | 23 | |
14b470b5 AB |
24 | struct seq_file; |
25 | ||
88459642 OS |
26 | /** |
27 | * struct sbitmap_word - Word in a &struct sbitmap. | |
28 | */ | |
29 | struct sbitmap_word { | |
30 | /** | |
ea86ea2c | 31 | * @depth: Number of bits being used in @word/@cleared |
88459642 | 32 | */ |
ea86ea2c | 33 | unsigned long depth; |
88459642 OS |
34 | |
35 | /** | |
ea86ea2c | 36 | * @word: word holding free bits |
88459642 | 37 | */ |
ea86ea2c JA |
38 | unsigned long word ____cacheline_aligned_in_smp; |
39 | ||
40 | /** | |
41 | * @cleared: word holding cleared bits | |
42 | */ | |
43 | unsigned long cleared ____cacheline_aligned_in_smp; | |
88459642 OS |
44 | } ____cacheline_aligned_in_smp; |
45 | ||
46 | /** | |
47 | * struct sbitmap - Scalable bitmap. | |
48 | * | |
49 | * A &struct sbitmap is spread over multiple cachelines to avoid ping-pong. This | |
50 | * trades off higher memory usage for better scalability. | |
51 | */ | |
52 | struct sbitmap { | |
53 | /** | |
54 | * @depth: Number of bits used in the whole bitmap. | |
55 | */ | |
56 | unsigned int depth; | |
57 | ||
58 | /** | |
59 | * @shift: log2(number of bits used per word) | |
60 | */ | |
61 | unsigned int shift; | |
62 | ||
63 | /** | |
64 | * @map_nr: Number of words (cachelines) being used for the bitmap. | |
65 | */ | |
66 | unsigned int map_nr; | |
67 | ||
efe1f3a1 ML |
68 | /** |
69 | * @round_robin: Allocate bits in strict round-robin order. | |
70 | */ | |
71 | bool round_robin; | |
72 | ||
88459642 OS |
73 | /** |
74 | * @map: Allocated bitmap. | |
75 | */ | |
76 | struct sbitmap_word *map; | |
c548e62b ML |
77 | |
78 | /* | |
79 | * @alloc_hint: Cache of last successfully allocated or freed bit. | |
80 | * | |
81 | * This is per-cpu, which allows multiple users to stick to different | |
82 | * cachelines until the map is exhausted. | |
83 | */ | |
84 | unsigned int __percpu *alloc_hint; | |
88459642 OS |
85 | }; |
86 | ||
87 | #define SBQ_WAIT_QUEUES 8 | |
88 | #define SBQ_WAKE_BATCH 8 | |
89 | ||
90 | /** | |
91 | * struct sbq_wait_state - Wait queue in a &struct sbitmap_queue. | |
92 | */ | |
93 | struct sbq_wait_state { | |
94 | /** | |
95 | * @wait_cnt: Number of frees remaining before we wake up. | |
96 | */ | |
97 | atomic_t wait_cnt; | |
98 | ||
99 | /** | |
100 | * @wait: Wait queue. | |
101 | */ | |
102 | wait_queue_head_t wait; | |
103 | } ____cacheline_aligned_in_smp; | |
104 | ||
105 | /** | |
106 | * struct sbitmap_queue - Scalable bitmap with the added ability to wait on free | |
107 | * bits. | |
108 | * | |
109 | * A &struct sbitmap_queue uses multiple wait queues and rolling wakeups to | |
110 | * avoid contention on the wait queue spinlock. This ensures that we don't hit a | |
111 | * scalability wall when we run out of free bits and have to start putting tasks | |
112 | * to sleep. | |
113 | */ | |
114 | struct sbitmap_queue { | |
115 | /** | |
116 | * @sb: Scalable bitmap. | |
117 | */ | |
118 | struct sbitmap sb; | |
119 | ||
120 | /** | |
121 | * @wake_batch: Number of bits which must be freed before we wake up any | |
122 | * waiters. | |
123 | */ | |
124 | unsigned int wake_batch; | |
125 | ||
126 | /** | |
127 | * @wake_index: Next wait queue in @ws to wake up. | |
128 | */ | |
129 | atomic_t wake_index; | |
130 | ||
131 | /** | |
132 | * @ws: Wait queues. | |
133 | */ | |
134 | struct sbq_wait_state *ws; | |
f4a644db | 135 | |
5d2ee712 JA |
136 | /* |
137 | * @ws_active: count of currently active ws waitqueues | |
138 | */ | |
139 | atomic_t ws_active; | |
140 | ||
a3275539 OS |
141 | /** |
142 | * @min_shallow_depth: The minimum shallow depth which may be passed to | |
143 | * sbitmap_queue_get_shallow() or __sbitmap_queue_get_shallow(). | |
144 | */ | |
145 | unsigned int min_shallow_depth; | |
88459642 OS |
146 | }; |
147 | ||
148 | /** | |
149 | * sbitmap_init_node() - Initialize a &struct sbitmap on a specific memory node. | |
150 | * @sb: Bitmap to initialize. | |
151 | * @depth: Number of bits to allocate. | |
152 | * @shift: Use 2^@shift bits per word in the bitmap; if a negative number if | |
153 | * given, a good default is chosen. | |
154 | * @flags: Allocation flags. | |
155 | * @node: Memory node to allocate on. | |
efe1f3a1 ML |
156 | * @round_robin: If true, be stricter about allocation order; always allocate |
157 | * starting from the last allocated bit. This is less efficient | |
158 | * than the default behavior (false). | |
c548e62b ML |
159 | * @alloc_hint: If true, apply percpu hint for where to start searching for |
160 | * a free bit. | |
88459642 OS |
161 | * |
162 | * Return: Zero on success or negative errno on failure. | |
163 | */ | |
164 | int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift, | |
c548e62b | 165 | gfp_t flags, int node, bool round_robin, bool alloc_hint); |
88459642 OS |
166 | |
167 | /** | |
168 | * sbitmap_free() - Free memory used by a &struct sbitmap. | |
169 | * @sb: Bitmap to free. | |
170 | */ | |
171 | static inline void sbitmap_free(struct sbitmap *sb) | |
172 | { | |
c548e62b | 173 | free_percpu(sb->alloc_hint); |
88459642 OS |
174 | kfree(sb->map); |
175 | sb->map = NULL; | |
176 | } | |
177 | ||
178 | /** | |
179 | * sbitmap_resize() - Resize a &struct sbitmap. | |
180 | * @sb: Bitmap to resize. | |
181 | * @depth: New number of bits to resize to. | |
182 | * | |
183 | * Doesn't reallocate anything. It's up to the caller to ensure that the new | |
184 | * depth doesn't exceed the depth that the sb was initialized with. | |
185 | */ | |
186 | void sbitmap_resize(struct sbitmap *sb, unsigned int depth); | |
187 | ||
188 | /** | |
189 | * sbitmap_get() - Try to allocate a free bit from a &struct sbitmap. | |
190 | * @sb: Bitmap to allocate from. | |
88459642 | 191 | * |
4ace53f1 OS |
192 | * This operation provides acquire barrier semantics if it succeeds. |
193 | * | |
88459642 OS |
194 | * Return: Non-negative allocated bit number if successful, -1 otherwise. |
195 | */ | |
c548e62b | 196 | int sbitmap_get(struct sbitmap *sb); |
88459642 | 197 | |
c05e6673 OS |
198 | /** |
199 | * sbitmap_get_shallow() - Try to allocate a free bit from a &struct sbitmap, | |
200 | * limiting the depth used from each word. | |
201 | * @sb: Bitmap to allocate from. | |
c05e6673 OS |
202 | * @shallow_depth: The maximum number of bits to allocate from a single word. |
203 | * | |
204 | * This rather specific operation allows for having multiple users with | |
205 | * different allocation limits. E.g., there can be a high-priority class that | |
206 | * uses sbitmap_get() and a low-priority class that uses sbitmap_get_shallow() | |
207 | * with a @shallow_depth of (1 << (@sb->shift - 1)). Then, the low-priority | |
208 | * class can only allocate half of the total bits in the bitmap, preventing it | |
209 | * from starving out the high-priority class. | |
210 | * | |
211 | * Return: Non-negative allocated bit number if successful, -1 otherwise. | |
212 | */ | |
c548e62b | 213 | int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth); |
c05e6673 | 214 | |
88459642 OS |
215 | /** |
216 | * sbitmap_any_bit_set() - Check for a set bit in a &struct sbitmap. | |
217 | * @sb: Bitmap to check. | |
218 | * | |
219 | * Return: true if any bit in the bitmap is set, false otherwise. | |
220 | */ | |
221 | bool sbitmap_any_bit_set(const struct sbitmap *sb); | |
222 | ||
7930d0a0 ML |
223 | #define SB_NR_TO_INDEX(sb, bitnr) ((bitnr) >> (sb)->shift) |
224 | #define SB_NR_TO_BIT(sb, bitnr) ((bitnr) & ((1U << (sb)->shift) - 1U)) | |
225 | ||
88459642 OS |
226 | typedef bool (*sb_for_each_fn)(struct sbitmap *, unsigned int, void *); |
227 | ||
228 | /** | |
7930d0a0 ML |
229 | * __sbitmap_for_each_set() - Iterate over each set bit in a &struct sbitmap. |
230 | * @start: Where to start the iteration. | |
88459642 OS |
231 | * @sb: Bitmap to iterate over. |
232 | * @fn: Callback. Should return true to continue or false to break early. | |
233 | * @data: Pointer to pass to callback. | |
234 | * | |
235 | * This is inline even though it's non-trivial so that the function calls to the | |
236 | * callback will hopefully get optimized away. | |
237 | */ | |
7930d0a0 ML |
238 | static inline void __sbitmap_for_each_set(struct sbitmap *sb, |
239 | unsigned int start, | |
240 | sb_for_each_fn fn, void *data) | |
88459642 | 241 | { |
7930d0a0 ML |
242 | unsigned int index; |
243 | unsigned int nr; | |
244 | unsigned int scanned = 0; | |
88459642 | 245 | |
7930d0a0 ML |
246 | if (start >= sb->depth) |
247 | start = 0; | |
248 | index = SB_NR_TO_INDEX(sb, start); | |
249 | nr = SB_NR_TO_BIT(sb, start); | |
88459642 | 250 | |
7930d0a0 | 251 | while (scanned < sb->depth) { |
8c2def89 OS |
252 | unsigned long word; |
253 | unsigned int depth = min_t(unsigned int, | |
254 | sb->map[index].depth - nr, | |
7930d0a0 | 255 | sb->depth - scanned); |
88459642 | 256 | |
7930d0a0 | 257 | scanned += depth; |
8c2def89 OS |
258 | word = sb->map[index].word & ~sb->map[index].cleared; |
259 | if (!word) | |
7930d0a0 ML |
260 | goto next; |
261 | ||
262 | /* | |
263 | * On the first iteration of the outer loop, we need to add the | |
264 | * bit offset back to the size of the word for find_next_bit(). | |
265 | * On all other iterations, nr is zero, so this is a noop. | |
266 | */ | |
267 | depth += nr; | |
88459642 | 268 | while (1) { |
8c2def89 | 269 | nr = find_next_bit(&word, depth, nr); |
7930d0a0 | 270 | if (nr >= depth) |
88459642 | 271 | break; |
7930d0a0 | 272 | if (!fn(sb, (index << sb->shift) + nr, data)) |
88459642 OS |
273 | return; |
274 | ||
275 | nr++; | |
276 | } | |
7930d0a0 ML |
277 | next: |
278 | nr = 0; | |
279 | if (++index >= sb->map_nr) | |
280 | index = 0; | |
88459642 OS |
281 | } |
282 | } | |
283 | ||
7930d0a0 ML |
284 | /** |
285 | * sbitmap_for_each_set() - Iterate over each set bit in a &struct sbitmap. | |
286 | * @sb: Bitmap to iterate over. | |
287 | * @fn: Callback. Should return true to continue or false to break early. | |
288 | * @data: Pointer to pass to callback. | |
289 | */ | |
290 | static inline void sbitmap_for_each_set(struct sbitmap *sb, sb_for_each_fn fn, | |
291 | void *data) | |
292 | { | |
293 | __sbitmap_for_each_set(sb, 0, fn, data); | |
294 | } | |
88459642 OS |
295 | |
296 | static inline unsigned long *__sbitmap_word(struct sbitmap *sb, | |
297 | unsigned int bitnr) | |
298 | { | |
299 | return &sb->map[SB_NR_TO_INDEX(sb, bitnr)].word; | |
300 | } | |
301 | ||
302 | /* Helpers equivalent to the operations in asm/bitops.h and linux/bitmap.h */ | |
303 | ||
304 | static inline void sbitmap_set_bit(struct sbitmap *sb, unsigned int bitnr) | |
305 | { | |
306 | set_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr)); | |
307 | } | |
308 | ||
309 | static inline void sbitmap_clear_bit(struct sbitmap *sb, unsigned int bitnr) | |
310 | { | |
311 | clear_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr)); | |
312 | } | |
313 | ||
ea86ea2c JA |
314 | /* |
315 | * This one is special, since it doesn't actually clear the bit, rather it | |
316 | * sets the corresponding bit in the ->cleared mask instead. Paired with | |
1e4471e7 | 317 | * the caller doing sbitmap_deferred_clear() if a given index is full, which |
ea86ea2c JA |
318 | * will clear the previously freed entries in the corresponding ->word. |
319 | */ | |
320 | static inline void sbitmap_deferred_clear_bit(struct sbitmap *sb, unsigned int bitnr) | |
321 | { | |
322 | unsigned long *addr = &sb->map[SB_NR_TO_INDEX(sb, bitnr)].cleared; | |
323 | ||
324 | set_bit(SB_NR_TO_BIT(sb, bitnr), addr); | |
325 | } | |
326 | ||
c548e62b ML |
327 | /* |
328 | * Pair of sbitmap_get, and this one applies both cleared bit and | |
329 | * allocation hint. | |
330 | */ | |
331 | static inline void sbitmap_put(struct sbitmap *sb, unsigned int bitnr) | |
332 | { | |
333 | sbitmap_deferred_clear_bit(sb, bitnr); | |
334 | ||
335 | if (likely(sb->alloc_hint && !sb->round_robin && bitnr < sb->depth)) | |
035e9f47 | 336 | *raw_cpu_ptr(sb->alloc_hint) = bitnr; |
c548e62b ML |
337 | } |
338 | ||
88459642 OS |
339 | static inline int sbitmap_test_bit(struct sbitmap *sb, unsigned int bitnr) |
340 | { | |
341 | return test_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr)); | |
342 | } | |
343 | ||
2d13b1ea ML |
344 | static inline int sbitmap_calculate_shift(unsigned int depth) |
345 | { | |
346 | int shift = ilog2(BITS_PER_LONG); | |
347 | ||
348 | /* | |
349 | * If the bitmap is small, shrink the number of bits per word so | |
350 | * we spread over a few cachelines, at least. If less than 4 | |
351 | * bits, just forget about it, it's not going to work optimally | |
352 | * anyway. | |
353 | */ | |
354 | if (depth >= 4) { | |
355 | while ((4U << shift) > depth) | |
356 | shift--; | |
357 | } | |
358 | ||
359 | return shift; | |
360 | } | |
361 | ||
24af1ccf OS |
362 | /** |
363 | * sbitmap_show() - Dump &struct sbitmap information to a &struct seq_file. | |
364 | * @sb: Bitmap to show. | |
365 | * @m: struct seq_file to write to. | |
366 | * | |
367 | * This is intended for debugging. The format may change at any time. | |
368 | */ | |
369 | void sbitmap_show(struct sbitmap *sb, struct seq_file *m); | |
370 | ||
cbb9950b ML |
371 | |
372 | /** | |
373 | * sbitmap_weight() - Return how many set and not cleared bits in a &struct | |
374 | * sbitmap. | |
375 | * @sb: Bitmap to check. | |
376 | * | |
377 | * Return: How many set and not cleared bits set | |
378 | */ | |
379 | unsigned int sbitmap_weight(const struct sbitmap *sb); | |
380 | ||
24af1ccf OS |
381 | /** |
382 | * sbitmap_bitmap_show() - Write a hex dump of a &struct sbitmap to a &struct | |
383 | * seq_file. | |
384 | * @sb: Bitmap to show. | |
385 | * @m: struct seq_file to write to. | |
386 | * | |
387 | * This is intended for debugging. The output isn't guaranteed to be internally | |
388 | * consistent. | |
389 | */ | |
390 | void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m); | |
391 | ||
88459642 OS |
392 | /** |
393 | * sbitmap_queue_init_node() - Initialize a &struct sbitmap_queue on a specific | |
394 | * memory node. | |
395 | * @sbq: Bitmap queue to initialize. | |
396 | * @depth: See sbitmap_init_node(). | |
397 | * @shift: See sbitmap_init_node(). | |
f4a644db | 398 | * @round_robin: See sbitmap_get(). |
88459642 OS |
399 | * @flags: Allocation flags. |
400 | * @node: Memory node to allocate on. | |
401 | * | |
402 | * Return: Zero on success or negative errno on failure. | |
403 | */ | |
404 | int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth, | |
f4a644db | 405 | int shift, bool round_robin, gfp_t flags, int node); |
88459642 OS |
406 | |
407 | /** | |
408 | * sbitmap_queue_free() - Free memory used by a &struct sbitmap_queue. | |
409 | * | |
410 | * @sbq: Bitmap queue to free. | |
411 | */ | |
412 | static inline void sbitmap_queue_free(struct sbitmap_queue *sbq) | |
413 | { | |
414 | kfree(sbq->ws); | |
415 | sbitmap_free(&sbq->sb); | |
416 | } | |
417 | ||
180dccb0 LQ |
418 | /** |
419 | * sbitmap_queue_recalculate_wake_batch() - Recalculate wake batch | |
420 | * @sbq: Bitmap queue to recalculate wake batch. | |
421 | * @users: Number of shares. | |
422 | * | |
423 | * Like sbitmap_queue_update_wake_batch(), this will calculate wake batch | |
424 | * by depth. This interface is for HCTX shared tags or queue shared tags. | |
425 | */ | |
426 | void sbitmap_queue_recalculate_wake_batch(struct sbitmap_queue *sbq, | |
427 | unsigned int users); | |
428 | ||
88459642 OS |
429 | /** |
430 | * sbitmap_queue_resize() - Resize a &struct sbitmap_queue. | |
431 | * @sbq: Bitmap queue to resize. | |
432 | * @depth: New number of bits to resize to. | |
433 | * | |
434 | * Like sbitmap_resize(), this doesn't reallocate anything. It has to do | |
435 | * some extra work on the &struct sbitmap_queue, so it's not safe to just | |
436 | * resize the underlying &struct sbitmap. | |
437 | */ | |
438 | void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth); | |
439 | ||
40aabb67 OS |
440 | /** |
441 | * __sbitmap_queue_get() - Try to allocate a free bit from a &struct | |
442 | * sbitmap_queue with preemption already disabled. | |
443 | * @sbq: Bitmap queue to allocate from. | |
40aabb67 OS |
444 | * |
445 | * Return: Non-negative allocated bit number if successful, -1 otherwise. | |
446 | */ | |
f4a644db | 447 | int __sbitmap_queue_get(struct sbitmap_queue *sbq); |
40aabb67 | 448 | |
9672b0d4 JA |
449 | /** |
450 | * __sbitmap_queue_get_batch() - Try to allocate a batch of free bits | |
451 | * @sbq: Bitmap queue to allocate from. | |
452 | * @nr_tags: number of tags requested | |
453 | * @offset: offset to add to returned bits | |
454 | * | |
455 | * Return: Mask of allocated tags, 0 if none are found. Each tag allocated is | |
456 | * a bit in the mask returned, and the caller must add @offset to the value to | |
457 | * get the absolute tag value. | |
458 | */ | |
459 | unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags, | |
460 | unsigned int *offset); | |
461 | ||
c05e6673 OS |
462 | /** |
463 | * __sbitmap_queue_get_shallow() - Try to allocate a free bit from a &struct | |
464 | * sbitmap_queue, limiting the depth used from each word, with preemption | |
465 | * already disabled. | |
466 | * @sbq: Bitmap queue to allocate from. | |
467 | * @shallow_depth: The maximum number of bits to allocate from a single word. | |
468 | * See sbitmap_get_shallow(). | |
469 | * | |
a3275539 OS |
470 | * If you call this, make sure to call sbitmap_queue_min_shallow_depth() after |
471 | * initializing @sbq. | |
472 | * | |
c05e6673 OS |
473 | * Return: Non-negative allocated bit number if successful, -1 otherwise. |
474 | */ | |
475 | int __sbitmap_queue_get_shallow(struct sbitmap_queue *sbq, | |
476 | unsigned int shallow_depth); | |
477 | ||
40aabb67 OS |
478 | /** |
479 | * sbitmap_queue_get() - Try to allocate a free bit from a &struct | |
480 | * sbitmap_queue. | |
481 | * @sbq: Bitmap queue to allocate from. | |
40aabb67 OS |
482 | * @cpu: Output parameter; will contain the CPU we ran on (e.g., to be passed to |
483 | * sbitmap_queue_clear()). | |
484 | * | |
485 | * Return: Non-negative allocated bit number if successful, -1 otherwise. | |
486 | */ | |
f4a644db | 487 | static inline int sbitmap_queue_get(struct sbitmap_queue *sbq, |
40aabb67 OS |
488 | unsigned int *cpu) |
489 | { | |
490 | int nr; | |
491 | ||
492 | *cpu = get_cpu(); | |
f4a644db | 493 | nr = __sbitmap_queue_get(sbq); |
40aabb67 OS |
494 | put_cpu(); |
495 | return nr; | |
496 | } | |
497 | ||
c05e6673 OS |
498 | /** |
499 | * sbitmap_queue_get_shallow() - Try to allocate a free bit from a &struct | |
500 | * sbitmap_queue, limiting the depth used from each word. | |
501 | * @sbq: Bitmap queue to allocate from. | |
502 | * @cpu: Output parameter; will contain the CPU we ran on (e.g., to be passed to | |
503 | * sbitmap_queue_clear()). | |
504 | * @shallow_depth: The maximum number of bits to allocate from a single word. | |
505 | * See sbitmap_get_shallow(). | |
506 | * | |
a3275539 OS |
507 | * If you call this, make sure to call sbitmap_queue_min_shallow_depth() after |
508 | * initializing @sbq. | |
509 | * | |
c05e6673 OS |
510 | * Return: Non-negative allocated bit number if successful, -1 otherwise. |
511 | */ | |
512 | static inline int sbitmap_queue_get_shallow(struct sbitmap_queue *sbq, | |
513 | unsigned int *cpu, | |
514 | unsigned int shallow_depth) | |
515 | { | |
516 | int nr; | |
517 | ||
518 | *cpu = get_cpu(); | |
519 | nr = __sbitmap_queue_get_shallow(sbq, shallow_depth); | |
520 | put_cpu(); | |
521 | return nr; | |
522 | } | |
523 | ||
a3275539 OS |
524 | /** |
525 | * sbitmap_queue_min_shallow_depth() - Inform a &struct sbitmap_queue of the | |
526 | * minimum shallow depth that will be used. | |
527 | * @sbq: Bitmap queue in question. | |
528 | * @min_shallow_depth: The minimum shallow depth that will be passed to | |
529 | * sbitmap_queue_get_shallow() or __sbitmap_queue_get_shallow(). | |
530 | * | |
531 | * sbitmap_queue_clear() batches wakeups as an optimization. The batch size | |
532 | * depends on the depth of the bitmap. Since the shallow allocation functions | |
533 | * effectively operate with a different depth, the shallow depth must be taken | |
534 | * into account when calculating the batch size. This function must be called | |
535 | * with the minimum shallow depth that will be used. Failure to do so can result | |
536 | * in missed wakeups. | |
537 | */ | |
538 | void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq, | |
539 | unsigned int min_shallow_depth); | |
540 | ||
88459642 OS |
541 | /** |
542 | * sbitmap_queue_clear() - Free an allocated bit and wake up waiters on a | |
543 | * &struct sbitmap_queue. | |
544 | * @sbq: Bitmap to free from. | |
545 | * @nr: Bit number to free. | |
40aabb67 | 546 | * @cpu: CPU the bit was allocated on. |
88459642 | 547 | */ |
40aabb67 | 548 | void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr, |
f4a644db | 549 | unsigned int cpu); |
88459642 | 550 | |
1aec5e4a JA |
551 | /** |
552 | * sbitmap_queue_clear_batch() - Free a batch of allocated bits | |
553 | * &struct sbitmap_queue. | |
554 | * @sbq: Bitmap to free from. | |
555 | * @offset: offset for each tag in array | |
556 | * @tags: array of tags | |
557 | * @nr_tags: number of tags in array | |
558 | */ | |
559 | void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset, | |
560 | int *tags, int nr_tags); | |
561 | ||
88459642 OS |
562 | static inline int sbq_index_inc(int index) |
563 | { | |
564 | return (index + 1) & (SBQ_WAIT_QUEUES - 1); | |
565 | } | |
566 | ||
567 | static inline void sbq_index_atomic_inc(atomic_t *index) | |
568 | { | |
569 | int old = atomic_read(index); | |
570 | int new = sbq_index_inc(old); | |
571 | atomic_cmpxchg(index, old, new); | |
572 | } | |
573 | ||
574 | /** | |
575 | * sbq_wait_ptr() - Get the next wait queue to use for a &struct | |
576 | * sbitmap_queue. | |
577 | * @sbq: Bitmap queue to wait on. | |
578 | * @wait_index: A counter per "user" of @sbq. | |
579 | */ | |
580 | static inline struct sbq_wait_state *sbq_wait_ptr(struct sbitmap_queue *sbq, | |
581 | atomic_t *wait_index) | |
582 | { | |
583 | struct sbq_wait_state *ws; | |
584 | ||
585 | ws = &sbq->ws[atomic_read(wait_index)]; | |
586 | sbq_index_atomic_inc(wait_index); | |
587 | return ws; | |
588 | } | |
589 | ||
590 | /** | |
591 | * sbitmap_queue_wake_all() - Wake up everything waiting on a &struct | |
592 | * sbitmap_queue. | |
593 | * @sbq: Bitmap queue to wake up. | |
594 | */ | |
595 | void sbitmap_queue_wake_all(struct sbitmap_queue *sbq); | |
596 | ||
e6fc4649 ML |
597 | /** |
598 | * sbitmap_queue_wake_up() - Wake up some of waiters in one waitqueue | |
599 | * on a &struct sbitmap_queue. | |
600 | * @sbq: Bitmap queue to wake up. | |
601 | */ | |
602 | void sbitmap_queue_wake_up(struct sbitmap_queue *sbq); | |
603 | ||
24af1ccf OS |
604 | /** |
605 | * sbitmap_queue_show() - Dump &struct sbitmap_queue information to a &struct | |
606 | * seq_file. | |
607 | * @sbq: Bitmap queue to show. | |
608 | * @m: struct seq_file to write to. | |
609 | * | |
610 | * This is intended for debugging. The format may change at any time. | |
611 | */ | |
612 | void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m); | |
613 | ||
5d2ee712 | 614 | struct sbq_wait { |
9f6b7ef6 | 615 | struct sbitmap_queue *sbq; /* if set, sbq_wait is accounted */ |
5d2ee712 JA |
616 | struct wait_queue_entry wait; |
617 | }; | |
618 | ||
619 | #define DEFINE_SBQ_WAIT(name) \ | |
620 | struct sbq_wait name = { \ | |
9f6b7ef6 | 621 | .sbq = NULL, \ |
5d2ee712 JA |
622 | .wait = { \ |
623 | .private = current, \ | |
624 | .func = autoremove_wake_function, \ | |
625 | .entry = LIST_HEAD_INIT((name).wait.entry), \ | |
626 | } \ | |
627 | } | |
628 | ||
629 | /* | |
630 | * Wrapper around prepare_to_wait_exclusive(), which maintains some extra | |
631 | * internal state. | |
632 | */ | |
633 | void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq, | |
634 | struct sbq_wait_state *ws, | |
635 | struct sbq_wait *sbq_wait, int state); | |
636 | ||
637 | /* | |
638 | * Must be paired with sbitmap_prepare_to_wait(). | |
639 | */ | |
640 | void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws, | |
641 | struct sbq_wait *sbq_wait); | |
642 | ||
9f6b7ef6 JA |
643 | /* |
644 | * Wrapper around add_wait_queue(), which maintains some extra internal state | |
645 | */ | |
646 | void sbitmap_add_wait_queue(struct sbitmap_queue *sbq, | |
647 | struct sbq_wait_state *ws, | |
648 | struct sbq_wait *sbq_wait); | |
649 | ||
650 | /* | |
651 | * Must be paired with sbitmap_add_wait_queue() | |
652 | */ | |
653 | void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait); | |
654 | ||
88459642 | 655 | #endif /* __LINUX_SCALE_BITMAP_H */ |