Commit | Line | Data |
---|---|---|
7ebd796f JA |
1 | /* |
2 | * Bitmap of bitmaps, where each layer is number-of-bits-per-word smaller than | |
3 | * the previous. Hence an 'axmap', since we axe each previous layer into a | |
4 | * much smaller piece. I swear, that is why it's named like that. It has | |
5 | * nothing to do with anything remotely narcissistic. | |
6 | * | |
7 | * A set bit at layer N indicates a full word at layer N-1, and so forth. As | |
de8f6de9 | 8 | * the bitmap becomes progressively more full, checking for existence |
7ebd796f JA |
9 | * becomes cheaper (since fewer layers are walked, making it a lot more |
10 | * cache friendly) and locating the next free space likewise. | |
11 | * | |
12 | * Axmaps get pretty close to optimal (1 bit per block) space usage, since | |
13 | * layers quickly diminish in size. Doing the size math is straight forward, | |
14 | * since we have log64(blocks) layers of maps. For 20000 blocks, overhead | |
15 | * is roughly 1.9%, or 1.019 bits per block. The number quickly converges | |
16 | * towards 1.0158, or 1.58% of overhead. | |
17 | */ | |
18 | #include <stdio.h> | |
19 | #include <stdlib.h> | |
20 | #include <string.h> | |
21 | #include <assert.h> | |
22 | ||
23 | #include "../arch/arch.h" | |
24 | #include "axmap.h" | |
25 | #include "../smalloc.h" | |
12bde369 | 26 | #include "../mutex.h" |
7ebd796f JA |
27 | #include "../minmax.h" |
28 | ||
29 | #if BITS_PER_LONG == 64 | |
30 | #define UNIT_SHIFT 6 | |
31 | #elif BITS_PER_LONG == 32 | |
32 | #define UNIT_SHIFT 5 | |
33 | #else | |
34 | #error "Number of arch bits unknown" | |
35 | #endif | |
36 | ||
e6f735f0 | 37 | #define BLOCKS_PER_UNIT (1U << UNIT_SHIFT) |
7ebd796f JA |
38 | #define BLOCKS_PER_UNIT_MASK (BLOCKS_PER_UNIT - 1) |
39 | ||
40 | #define firstfree_valid(b) ((b)->first_free != (uint64_t) -1) | |
41 | ||
42 | struct axmap_level { | |
43 | int level; | |
44 | unsigned long map_size; | |
45 | unsigned long *map; | |
46 | }; | |
47 | ||
48 | struct axmap { | |
12bde369 | 49 | struct fio_mutex lock; |
7ebd796f JA |
50 | unsigned int nr_levels; |
51 | struct axmap_level *levels; | |
52 | uint64_t first_free; | |
47d94b0b | 53 | uint64_t nr_bits; |
7ebd796f JA |
54 | }; |
55 | ||
56 | static unsigned long ulog64(unsigned long val, unsigned int log) | |
57 | { | |
58 | while (log-- && val) | |
59 | val >>= UNIT_SHIFT; | |
60 | ||
61 | return val; | |
62 | } | |
63 | ||
64 | void axmap_reset(struct axmap *axmap) | |
65 | { | |
66 | int i; | |
67 | ||
12bde369 JA |
68 | fio_mutex_down(&axmap->lock); |
69 | ||
7ebd796f JA |
70 | for (i = 0; i < axmap->nr_levels; i++) { |
71 | struct axmap_level *al = &axmap->levels[i]; | |
72 | ||
73 | memset(al->map, 0, al->map_size * sizeof(unsigned long)); | |
74 | } | |
17f0fd39 JA |
75 | |
76 | axmap->first_free = 0; | |
12bde369 | 77 | fio_mutex_up(&axmap->lock); |
7ebd796f JA |
78 | } |
79 | ||
80 | void axmap_free(struct axmap *axmap) | |
81 | { | |
82 | unsigned int i; | |
83 | ||
84 | if (!axmap) | |
85 | return; | |
86 | ||
87 | for (i = 0; i < axmap->nr_levels; i++) | |
88 | sfree(axmap->levels[i].map); | |
89 | ||
90 | sfree(axmap->levels); | |
12bde369 | 91 | __fio_mutex_remove(&axmap->lock); |
7ebd796f JA |
92 | sfree(axmap); |
93 | } | |
94 | ||
95 | struct axmap *axmap_new(unsigned long nr_bits) | |
96 | { | |
97 | struct axmap *axmap; | |
98 | unsigned int i, levels; | |
99 | ||
100 | axmap = smalloc(sizeof(*axmap)); | |
101 | if (!axmap) | |
102 | return NULL; | |
103 | ||
12bde369 JA |
104 | __fio_mutex_init(&axmap->lock, FIO_MUTEX_UNLOCKED); |
105 | ||
7ebd796f JA |
106 | levels = 1; |
107 | i = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
108 | while (i > 1) { | |
109 | i = (i + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
110 | levels++; | |
111 | } | |
112 | ||
113 | axmap->nr_levels = levels; | |
114 | axmap->levels = smalloc(axmap->nr_levels * sizeof(struct axmap_level)); | |
47d94b0b | 115 | axmap->nr_bits = nr_bits; |
7ebd796f JA |
116 | |
117 | for (i = 0; i < axmap->nr_levels; i++) { | |
118 | struct axmap_level *al = &axmap->levels[i]; | |
119 | ||
120 | al->level = i; | |
121 | al->map_size = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
122 | al->map = smalloc(al->map_size * sizeof(unsigned long)); | |
123 | if (!al->map) | |
124 | goto err; | |
125 | ||
126 | nr_bits = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT; | |
127 | } | |
128 | ||
129 | axmap_reset(axmap); | |
130 | return axmap; | |
131 | err: | |
132 | for (i = 0; i < axmap->nr_levels; i++) | |
133 | if (axmap->levels[i].map) | |
134 | sfree(axmap->levels[i].map); | |
135 | ||
136 | sfree(axmap->levels); | |
12bde369 JA |
137 | __fio_mutex_remove(&axmap->lock); |
138 | sfree(axmap); | |
7ebd796f JA |
139 | return NULL; |
140 | } | |
141 | ||
142 | static int axmap_handler(struct axmap *axmap, uint64_t bit_nr, | |
143 | int (*func)(struct axmap_level *, unsigned long, unsigned int, | |
144 | void *), void *data) | |
145 | { | |
146 | struct axmap_level *al; | |
147 | int i; | |
148 | ||
149 | for (i = 0; i < axmap->nr_levels; i++) { | |
150 | unsigned long index = ulog64(bit_nr, i); | |
151 | unsigned long offset = index >> UNIT_SHIFT; | |
152 | unsigned int bit = index & BLOCKS_PER_UNIT_MASK; | |
153 | ||
154 | al = &axmap->levels[i]; | |
155 | ||
156 | if (func(al, offset, bit, data)) | |
157 | return 1; | |
158 | } | |
159 | ||
160 | return 0; | |
161 | } | |
162 | ||
163 | static int axmap_handler_topdown(struct axmap *axmap, uint64_t bit_nr, | |
164 | int (*func)(struct axmap_level *, unsigned long, unsigned int, void *), | |
165 | void *data) | |
166 | { | |
167 | struct axmap_level *al; | |
168 | int i, level = axmap->nr_levels; | |
169 | ||
170 | for (i = axmap->nr_levels - 1; i >= 0; i--) { | |
171 | unsigned long index = ulog64(bit_nr, --level); | |
172 | unsigned long offset = index >> UNIT_SHIFT; | |
173 | unsigned int bit = index & BLOCKS_PER_UNIT_MASK; | |
174 | ||
175 | al = &axmap->levels[i]; | |
176 | ||
177 | if (func(al, offset, bit, data)) | |
178 | return 1; | |
179 | } | |
180 | ||
181 | return 0; | |
182 | } | |
183 | ||
184 | static int axmap_clear_fn(struct axmap_level *al, unsigned long offset, | |
185 | unsigned int bit, void *unused) | |
186 | { | |
187 | if (!(al->map[offset] & (1UL << bit))) | |
188 | return 1; | |
189 | ||
190 | al->map[offset] &= ~(1UL << bit); | |
191 | return 0; | |
192 | } | |
193 | ||
194 | void axmap_clear(struct axmap *axmap, uint64_t bit_nr) | |
195 | { | |
196 | axmap_handler(axmap, bit_nr, axmap_clear_fn, NULL); | |
197 | } | |
198 | ||
199 | struct axmap_set_data { | |
200 | unsigned int nr_bits; | |
201 | unsigned int set_bits; | |
7ebd796f JA |
202 | }; |
203 | ||
204 | static unsigned long bit_masks[] = { | |
205 | 0x0000000000000000, 0x0000000000000001, 0x0000000000000003, 0x0000000000000007, | |
206 | 0x000000000000000f, 0x000000000000001f, 0x000000000000003f, 0x000000000000007f, | |
207 | 0x00000000000000ff, 0x00000000000001ff, 0x00000000000003ff, 0x00000000000007ff, | |
208 | 0x0000000000000fff, 0x0000000000001fff, 0x0000000000003fff, 0x0000000000007fff, | |
209 | 0x000000000000ffff, 0x000000000001ffff, 0x000000000003ffff, 0x000000000007ffff, | |
210 | 0x00000000000fffff, 0x00000000001fffff, 0x00000000003fffff, 0x00000000007fffff, | |
211 | 0x0000000000ffffff, 0x0000000001ffffff, 0x0000000003ffffff, 0x0000000007ffffff, | |
212 | 0x000000000fffffff, 0x000000001fffffff, 0x000000003fffffff, 0x000000007fffffff, | |
213 | 0x00000000ffffffff, | |
214 | #if BITS_PER_LONG == 64 | |
215 | 0x00000001ffffffff, 0x00000003ffffffff, 0x00000007ffffffff, 0x0000000fffffffff, | |
216 | 0x0000001fffffffff, 0x0000003fffffffff, 0x0000007fffffffff, 0x000000ffffffffff, | |
217 | 0x000001ffffffffff, 0x000003ffffffffff, 0x000007ffffffffff, 0x00000fffffffffff, | |
218 | 0x00001fffffffffff, 0x00003fffffffffff, 0x00007fffffffffff, 0x0000ffffffffffff, | |
219 | 0x0001ffffffffffff, 0x0003ffffffffffff, 0x0007ffffffffffff, 0x000fffffffffffff, | |
220 | 0x001fffffffffffff, 0x003fffffffffffff, 0x007fffffffffffff, 0x00ffffffffffffff, | |
221 | 0x01ffffffffffffff, 0x03ffffffffffffff, 0x07ffffffffffffff, 0x0fffffffffffffff, | |
222 | 0x1fffffffffffffff, 0x3fffffffffffffff, 0x7fffffffffffffff, 0xffffffffffffffff | |
223 | #endif | |
224 | }; | |
225 | ||
226 | static int axmap_set_fn(struct axmap_level *al, unsigned long offset, | |
227 | unsigned int bit, void *__data) | |
228 | { | |
229 | struct axmap_set_data *data = __data; | |
230 | unsigned long mask, overlap; | |
231 | unsigned int nr_bits; | |
232 | ||
233 | nr_bits = min(data->nr_bits, BLOCKS_PER_UNIT - bit); | |
234 | ||
235 | mask = bit_masks[nr_bits] << bit; | |
236 | ||
237 | /* | |
238 | * Mask off any potential overlap, only sets contig regions | |
239 | */ | |
240 | overlap = al->map[offset] & mask; | |
09d6bf09 | 241 | if (overlap == mask) |
7ebd796f | 242 | return 1; |
7ebd796f JA |
243 | |
244 | while (overlap) { | |
245 | unsigned long clear_mask = ~(1UL << ffz(~overlap)); | |
246 | ||
247 | mask &= clear_mask; | |
248 | overlap &= clear_mask; | |
249 | nr_bits--; | |
250 | } | |
251 | ||
252 | assert(mask); | |
253 | assert(!(al->map[offset] & mask)); | |
254 | ||
255 | al->map[offset] |= mask; | |
256 | ||
257 | if (!al->level) | |
258 | data->set_bits = nr_bits; | |
259 | ||
260 | data->nr_bits = 1; | |
261 | return al->map[offset] != -1UL; | |
262 | } | |
263 | ||
264 | static void __axmap_set(struct axmap *axmap, uint64_t bit_nr, | |
265 | struct axmap_set_data *data) | |
266 | { | |
267 | unsigned int set_bits, nr_bits = data->nr_bits; | |
268 | ||
269 | if (axmap->first_free >= bit_nr && | |
270 | axmap->first_free < bit_nr + data->nr_bits) | |
271 | axmap->first_free = -1ULL; | |
272 | ||
47d94b0b JA |
273 | if (bit_nr > axmap->nr_bits) |
274 | return; | |
275 | else if (bit_nr + nr_bits > axmap->nr_bits) | |
276 | nr_bits = axmap->nr_bits - bit_nr; | |
277 | ||
7ebd796f JA |
278 | set_bits = 0; |
279 | while (nr_bits) { | |
280 | axmap_handler(axmap, bit_nr, axmap_set_fn, data); | |
281 | set_bits += data->set_bits; | |
282 | ||
0bfdf9f1 JA |
283 | if (!data->set_bits || |
284 | data->set_bits != (BLOCKS_PER_UNIT - nr_bits)) | |
7ebd796f JA |
285 | break; |
286 | ||
287 | nr_bits -= data->set_bits; | |
288 | bit_nr += data->set_bits; | |
289 | ||
290 | data->nr_bits = nr_bits; | |
7ebd796f JA |
291 | } |
292 | ||
293 | data->set_bits = set_bits; | |
294 | } | |
295 | ||
296 | void axmap_set(struct axmap *axmap, uint64_t bit_nr) | |
297 | { | |
298 | struct axmap_set_data data = { .nr_bits = 1, }; | |
299 | ||
12bde369 | 300 | fio_mutex_down(&axmap->lock); |
7ebd796f | 301 | __axmap_set(axmap, bit_nr, &data); |
12bde369 | 302 | fio_mutex_up(&axmap->lock); |
7ebd796f JA |
303 | } |
304 | ||
305 | unsigned int axmap_set_nr(struct axmap *axmap, uint64_t bit_nr, unsigned int nr_bits) | |
306 | { | |
0bfdf9f1 JA |
307 | unsigned int set_bits = 0; |
308 | ||
309 | do { | |
09d6bf09 | 310 | struct axmap_set_data data = { .nr_bits = nr_bits, }; |
0bfdf9f1 JA |
311 | unsigned int max_bits, this_set; |
312 | ||
313 | max_bits = BLOCKS_PER_UNIT - (bit_nr & BLOCKS_PER_UNIT_MASK); | |
314 | if (max_bits < nr_bits) | |
315 | data.nr_bits = max_bits; | |
316 | ||
317 | this_set = data.nr_bits; | |
318 | __axmap_set(axmap, bit_nr, &data); | |
319 | set_bits += data.set_bits; | |
320 | if (data.set_bits != this_set) | |
321 | break; | |
7ebd796f | 322 | |
0bfdf9f1 JA |
323 | nr_bits -= data.set_bits; |
324 | bit_nr += data.set_bits; | |
325 | } while (nr_bits); | |
326 | ||
327 | return set_bits; | |
7ebd796f JA |
328 | } |
329 | ||
330 | static int axmap_isset_fn(struct axmap_level *al, unsigned long offset, | |
331 | unsigned int bit, void *unused) | |
332 | { | |
333 | return (al->map[offset] & (1UL << bit)) != 0; | |
334 | } | |
335 | ||
336 | int axmap_isset(struct axmap *axmap, uint64_t bit_nr) | |
337 | { | |
12bde369 JA |
338 | if (bit_nr <= axmap->nr_bits) { |
339 | int ret; | |
340 | ||
341 | fio_mutex_down(&axmap->lock); | |
342 | ret = axmap_handler_topdown(axmap, bit_nr, axmap_isset_fn, NULL); | |
343 | fio_mutex_up(&axmap->lock); | |
344 | return ret; | |
345 | } | |
47d94b0b JA |
346 | |
347 | return 0; | |
7ebd796f JA |
348 | } |
349 | ||
350 | static uint64_t axmap_find_first_free(struct axmap *axmap, unsigned int level, | |
351 | uint64_t index) | |
352 | { | |
731ef4c7 | 353 | uint64_t ret = -1ULL; |
7ebd796f | 354 | unsigned long j; |
731ef4c7 | 355 | int i; |
7ebd796f JA |
356 | |
357 | /* | |
358 | * Start at the bottom, then converge towards first free bit at the top | |
359 | */ | |
360 | for (i = level; i >= 0; i--) { | |
361 | struct axmap_level *al = &axmap->levels[i]; | |
362 | ||
731ef4c7 JA |
363 | /* |
364 | * Clear 'ret', this is a bug condition. | |
365 | */ | |
7ebd796f | 366 | if (index >= al->map_size) { |
731ef4c7 | 367 | ret = -1ULL; |
7ebd796f JA |
368 | break; |
369 | } | |
370 | ||
371 | for (j = index; j < al->map_size; j++) { | |
372 | if (al->map[j] == -1UL) | |
373 | continue; | |
374 | ||
375 | /* | |
376 | * First free bit here is our index into the first | |
377 | * free bit at the next higher level | |
378 | */ | |
731ef4c7 | 379 | ret = index = (j << UNIT_SHIFT) + ffz(al->map[j]); |
7ebd796f JA |
380 | break; |
381 | } | |
382 | } | |
383 | ||
47d94b0b JA |
384 | if (ret < axmap->nr_bits) |
385 | return ret; | |
386 | ||
387 | return (uint64_t) -1ULL; | |
7ebd796f JA |
388 | } |
389 | ||
d555a23d | 390 | static uint64_t axmap_first_free(struct axmap *axmap) |
7ebd796f | 391 | { |
12bde369 JA |
392 | uint64_t ret; |
393 | ||
7ebd796f JA |
394 | if (firstfree_valid(axmap)) |
395 | return axmap->first_free; | |
396 | ||
12bde369 JA |
397 | ret = axmap_find_first_free(axmap, axmap->nr_levels - 1, 0); |
398 | axmap->first_free = ret; | |
12bde369 JA |
399 | |
400 | return ret; | |
7ebd796f JA |
401 | } |
402 | ||
403 | struct axmap_next_free_data { | |
404 | unsigned int level; | |
405 | unsigned long offset; | |
406 | uint64_t bit; | |
407 | }; | |
408 | ||
409 | static int axmap_next_free_fn(struct axmap_level *al, unsigned long offset, | |
410 | unsigned int bit, void *__data) | |
411 | { | |
412 | struct axmap_next_free_data *data = __data; | |
53737ae0 | 413 | uint64_t mask = ~bit_masks[(data->bit + 1) & BLOCKS_PER_UNIT_MASK]; |
7ebd796f | 414 | |
53737ae0 | 415 | if (!(mask & ~al->map[offset])) |
7ebd796f JA |
416 | return 0; |
417 | ||
418 | if (al->map[offset] != -1UL) { | |
419 | data->level = al->level; | |
420 | data->offset = offset; | |
421 | return 1; | |
422 | } | |
423 | ||
424 | data->bit = (data->bit + BLOCKS_PER_UNIT - 1) / BLOCKS_PER_UNIT; | |
425 | return 0; | |
426 | } | |
427 | ||
428 | /* | |
429 | * 'bit_nr' is already set. Find the next free bit after this one. | |
430 | */ | |
431 | uint64_t axmap_next_free(struct axmap *axmap, uint64_t bit_nr) | |
432 | { | |
433 | struct axmap_next_free_data data = { .level = -1U, .bit = bit_nr, }; | |
53737ae0 | 434 | uint64_t ret; |
7ebd796f | 435 | |
12bde369 | 436 | fio_mutex_down(&axmap->lock); |
7ebd796f | 437 | |
12bde369 JA |
438 | if (firstfree_valid(axmap) && bit_nr < axmap->first_free) { |
439 | ret = axmap->first_free; | |
440 | goto done; | |
441 | } | |
442 | ||
443 | if (!axmap_handler(axmap, bit_nr, axmap_next_free_fn, &data)) { | |
444 | ret = axmap_first_free(axmap); | |
445 | goto done; | |
446 | } | |
7ebd796f JA |
447 | |
448 | assert(data.level != -1U); | |
449 | ||
53737ae0 JA |
450 | /* |
451 | * In the rare case that the map is unaligned, we might end up | |
452 | * finding an offset that's beyond the valid end. For that case, | |
453 | * find the first free one, the map is practically full. | |
454 | */ | |
455 | ret = axmap_find_first_free(axmap, data.level, data.offset); | |
12bde369 JA |
456 | if (ret != -1ULL) { |
457 | done: | |
458 | fio_mutex_up(&axmap->lock); | |
53737ae0 | 459 | return ret; |
12bde369 | 460 | } |
53737ae0 | 461 | |
12bde369 JA |
462 | ret = axmap_first_free(axmap); |
463 | goto done; | |
7ebd796f | 464 | } |