FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_unit.c
1 /*-
2 * Copyright (c) 2004 Poul-Henning Kamp
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: releng/6.1/sys/kern/subr_unit.c 158179 2006-04-30 16:44:43Z cvs2svn $
27 *
28 *
29 * Unit number allocation functions.
30 *
31 * These functions implement a mixed run-length/bitmap management of unit
32 * number spaces in a very memory efficient manner.
33 *
34 * Allocation policy is always lowest free number first.
35 *
36 * A return value of -1 signals that no more unit numbers are available.
37 *
38 * There is no cost associated with the range of unitnumbers, so unless
39 * the resource really is finite, specify INT_MAX to new_unrhdr() and
40 * forget about checking the return value.
41 *
42 * If a mutex is not provided when the unit number space is created, a
43 * default global mutex is used. The advantage to passing a mutex in, is
44 * that the the alloc_unrl() function can be called with the mutex already
45 * held (it will not be released by alloc_unrl()).
46 *
47 * The allocation function alloc_unr{l}() never sleeps (but it may block on
48 * the mutex of course).
49 *
50 * Freeing a unit number may require allocating memory, and can therefore
51 * sleep so the free_unr() function does not come in a pre-locked variant.
52 *
53 * A userland test program is included.
54 *
55 * Memory usage is a very complex function of the the exact allocation
56 * pattern, but always very compact:
57 * * For the very typical case where a single unbroken run of unit
58 * numbers are allocated 44 bytes are used on i386.
59 * * For a unit number space of 1000 units and the random pattern
60 * in the usermode test program included, the worst case usage
61 * was 252 bytes on i386 for 500 allocated and 500 free units.
62 * * For a unit number space of 10000 units and the random pattern
63 * in the usermode test program included, the worst case usage
64 * was 798 bytes on i386 for 5000 allocated and 5000 free units.
65 * * The worst case is where every other unit number is allocated and
66 * the the rest are free. In that case 44 + N/4 bytes are used where
67 * N is the number of the highest unit allocated.
68 */
69
70 #include <sys/types.h>
71 #include <sys/queue.h>
72 #include <sys/bitstring.h>
73
74 #ifdef _KERNEL
75
76 #include <sys/param.h>
77 #include <sys/malloc.h>
78 #include <sys/kernel.h>
79 #include <sys/systm.h>
80 #include <sys/limits.h>
81 #include <sys/lock.h>
82 #include <sys/mutex.h>
83
84 /*
85 * In theory it would be smarter to allocate the individual blocks
86 * with the zone allocator, but at this time the expectation is that
87 * there will typically not even be enough allocations to fill a single
88 * page, so we stick with malloc for now.
89 */
90 static MALLOC_DEFINE(M_UNIT, "Unitno", "Unit number allocation");
91
92 #define Malloc(foo) malloc(foo, M_UNIT, M_WAITOK | M_ZERO)
93 #define Free(foo) free(foo, M_UNIT)
94
95 static struct mtx unitmtx;
96
97 MTX_SYSINIT(unit, &unitmtx, "unit# allocation", MTX_DEF);
98
99 #else /* ...USERLAND */
100
101 #include <stdio.h>
102 #include <stdlib.h>
103 #include <string.h>
104
105 #define KASSERT(cond, arg) \
106 do { \
107 if (!(cond)) { \
108 printf arg; \
109 abort(); \
110 } \
111 } while (0)
112
113 static int no_alloc;
114 #define Malloc(foo) _Malloc(foo, __LINE__)
115 static void *
116 _Malloc(size_t foo, int line)
117 {
118
119 KASSERT(no_alloc == 0, ("malloc in wrong place() line %d", line));
120 return (calloc(foo, 1));
121 }
122 #define Free(foo) free(foo)
123
124 struct unrhdr;
125
126
127 struct mtx {
128 int state;
129 } unitmtx;
130
131 static void
132 mtx_lock(struct mtx *mp)
133 {
134 KASSERT(mp->state == 0, ("mutex already locked"));
135 mp->state = 1;
136 }
137
138 static void
139 mtx_unlock(struct mtx *mp)
140 {
141 KASSERT(mp->state == 1, ("mutex not locked"));
142 mp->state = 0;
143 }
144
145 #define MA_OWNED 9
146
147 static void
148 mtx_assert(struct mtx *mp, int flag)
149 {
150 if (flag == MA_OWNED) {
151 KASSERT(mp->state == 1, ("mtx_assert(MA_OWNED) not true"));
152 }
153 }
154
155 #define CTASSERT(foo)
156
157 #endif /* USERLAND */
158
159 /*
160 * This is our basic building block.
161 *
162 * It can be used in three different ways depending on the value of the ptr
163 * element:
164 * If ptr is NULL, it represents a run of free items.
165 * If ptr points to the unrhdr it represents a run of allocated items.
166 * Otherwise it points to an bitstring of allocated items.
167 *
168 * For runs the len field is the length of the run.
169 * For bitmaps the len field represents the number of allocated items.
170 *
171 * The bitmap is the same size as struct unr to optimize memory management.
172 */
173 struct unr {
174 TAILQ_ENTRY(unr) list;
175 u_int len;
176 void *ptr;
177 };
178
179 struct unrb {
180 u_char busy;
181 bitstr_t map[sizeof(struct unr) - 1];
182 };
183
184 CTASSERT(sizeof(struct unr) == sizeof(struct unrb));
185
186 /* Number of bits in the bitmap */
187 #define NBITS ((int)sizeof(((struct unrb *)NULL)->map) * 8)
188
189 /* Header element for a unr number space. */
190
191 struct unrhdr {
192 TAILQ_HEAD(unrhd,unr) head;
193 u_int low; /* Lowest item */
194 u_int high; /* Highest item */
195 u_int busy; /* Count of allocated items */
196 u_int alloc; /* Count of memory allocations */
197 u_int first; /* items in allocated from start */
198 u_int last; /* items free at end */
199 struct mtx *mtx;
200 };
201
202
203 #if defined(DIAGNOSTIC) || !defined(_KERNEL)
204 /*
205 * Consistency check function.
206 *
207 * Checks the internal consistency as well as we can.
208 *
209 * Called at all boundaries of this API.
210 */
211 static void
212 check_unrhdr(struct unrhdr *uh, int line)
213 {
214 struct unr *up;
215 struct unrb *ub;
216 u_int x, y, z, w;
217
218 y = uh->first;
219 z = 0;
220 TAILQ_FOREACH(up, &uh->head, list) {
221 z++;
222 if (up->ptr != uh && up->ptr != NULL) {
223 ub = up->ptr;
224 KASSERT (up->len <= NBITS,
225 ("UNR inconsistency: len %u max %d (line %d)\n",
226 up->len, NBITS, line));
227 z++;
228 w = 0;
229 for (x = 0; x < up->len; x++)
230 if (bit_test(ub->map, x))
231 w++;
232 KASSERT (w == ub->busy,
233 ("UNR inconsistency: busy %u found %u (line %d)\n",
234 ub->busy, w, line));
235 y += w;
236 } else if (up->ptr != NULL)
237 y += up->len;
238 }
239 KASSERT (y == uh->busy,
240 ("UNR inconsistency: items %u found %u (line %d)\n",
241 uh->busy, y, line));
242 KASSERT (z == uh->alloc,
243 ("UNR inconsistency: chunks %u found %u (line %d)\n",
244 uh->alloc, z, line));
245 }
246
247 #else
248
249 static __inline void
250 check_unrhdr(struct unrhdr *uh, int line)
251 {
252
253 }
254
255 #endif
256
257
258 /*
259 * Userland memory management. Just use calloc and keep track of how
260 * many elements we have allocated for check_unrhdr().
261 */
262
263 static __inline void *
264 new_unr(struct unrhdr *uh, void **p1, void **p2)
265 {
266 void *p;
267
268 uh->alloc++;
269 KASSERT(*p1 != NULL || *p2 != NULL, ("Out of cached memory"));
270 if (*p1 != NULL) {
271 p = *p1;
272 *p1 = NULL;
273 return (p);
274 } else {
275 p = *p2;
276 *p2 = NULL;
277 return (p);
278 }
279 }
280
281 static __inline void
282 delete_unr(struct unrhdr *uh, void *ptr)
283 {
284
285 uh->alloc--;
286 Free(ptr);
287 }
288
289 /*
290 * Allocate a new unrheader set.
291 *
292 * Highest and lowest valid values given as paramters.
293 */
294
295 struct unrhdr *
296 new_unrhdr(int low, int high, struct mtx *mutex)
297 {
298 struct unrhdr *uh;
299
300 KASSERT(low <= high,
301 ("UNR: use error: new_unrhdr(%u, %u)", low, high));
302 uh = Malloc(sizeof *uh);
303 if (mutex != NULL)
304 uh->mtx = mutex;
305 else
306 uh->mtx = &unitmtx;
307 TAILQ_INIT(&uh->head);
308 uh->low = low;
309 uh->high = high;
310 uh->first = 0;
311 uh->last = 1 + (high - low);
312 check_unrhdr(uh, __LINE__);
313 return (uh);
314 }
315
316 void
317 delete_unrhdr(struct unrhdr *uh)
318 {
319
320 check_unrhdr(uh, __LINE__);
321 KASSERT(uh->busy == 0, ("unrhdr has %u allocations", uh->busy));
322 KASSERT(uh->alloc == 0, ("UNR memory leak in delete_unrhdr"));
323 Free(uh);
324 }
325
326 static __inline int
327 is_bitmap(struct unrhdr *uh, struct unr *up)
328 {
329 return (up->ptr != uh && up->ptr != NULL);
330 }
331
332 /*
333 * Look for sequence of items which can be combined into a bitmap, if
334 * multiple are present, take the one which saves most memory.
335 *
336 * Return (1) if a sequence was found to indicate that another call
337 * might be able to do more. Return (0) if we found no suitable sequence.
338 *
339 * NB: called from alloc_unr(), no new memory allocation allowed.
340 */
341 static int
342 optimize_unr(struct unrhdr *uh)
343 {
344 struct unr *up, *uf, *us;
345 struct unrb *ub, *ubf;
346 u_int a, l, ba;
347
348 /*
349 * Look for the run of items (if any) which when collapsed into
350 * a bitmap would save most memory.
351 */
352 us = NULL;
353 ba = 0;
354 TAILQ_FOREACH(uf, &uh->head, list) {
355 if (uf->len >= NBITS)
356 continue;
357 a = 1;
358 if (is_bitmap(uh, uf))
359 a++;
360 l = uf->len;
361 up = uf;
362 while (1) {
363 up = TAILQ_NEXT(up, list);
364 if (up == NULL)
365 break;
366 if ((up->len + l) > NBITS)
367 break;
368 a++;
369 if (is_bitmap(uh, up))
370 a++;
371 l += up->len;
372 }
373 if (a > ba) {
374 ba = a;
375 us = uf;
376 }
377 }
378 if (ba < 3)
379 return (0);
380
381 /*
382 * If the first element is not a bitmap, make it one.
383 * Trying to do so without allocating more memory complicates things
384 * a bit
385 */
386 if (!is_bitmap(uh, us)) {
387 uf = TAILQ_NEXT(us, list);
388 TAILQ_REMOVE(&uh->head, us, list);
389 a = us->len;
390 l = us->ptr == uh ? 1 : 0;
391 ub = (void *)us;
392 ub->busy = 0;
393 if (l) {
394 bit_nset(ub->map, 0, a);
395 ub->busy += a;
396 } else {
397 bit_nclear(ub->map, 0, a);
398 }
399 if (!is_bitmap(uh, uf)) {
400 if (uf->ptr == NULL) {
401 bit_nclear(ub->map, a, a + uf->len - 1);
402 } else {
403 bit_nset(ub->map, a, a + uf->len - 1);
404 ub->busy += uf->len;
405 }
406 uf->ptr = ub;
407 uf->len += a;
408 us = uf;
409 } else {
410 ubf = uf->ptr;
411 for (l = 0; l < uf->len; l++, a++) {
412 if (bit_test(ubf->map, l)) {
413 bit_set(ub->map, a);
414 ub->busy++;
415 } else {
416 bit_clear(ub->map, a);
417 }
418 }
419 uf->len = a;
420 delete_unr(uh, uf->ptr);
421 uf->ptr = ub;
422 us = uf;
423 }
424 }
425 ub = us->ptr;
426 while (1) {
427 uf = TAILQ_NEXT(us, list);
428 if (uf == NULL)
429 return (1);
430 if (uf->len + us->len > NBITS)
431 return (1);
432 if (uf->ptr == NULL) {
433 bit_nclear(ub->map, us->len, us->len + uf->len - 1);
434 us->len += uf->len;
435 TAILQ_REMOVE(&uh->head, uf, list);
436 delete_unr(uh, uf);
437 } else if (uf->ptr == uh) {
438 bit_nset(ub->map, us->len, us->len + uf->len - 1);
439 ub->busy += uf->len;
440 us->len += uf->len;
441 TAILQ_REMOVE(&uh->head, uf, list);
442 delete_unr(uh, uf);
443 } else {
444 ubf = uf->ptr;
445 for (l = 0; l < uf->len; l++, us->len++) {
446 if (bit_test(ubf->map, l)) {
447 bit_set(ub->map, us->len);
448 ub->busy++;
449 } else {
450 bit_clear(ub->map, us->len);
451 }
452 }
453 TAILQ_REMOVE(&uh->head, uf, list);
454 delete_unr(uh, ubf);
455 delete_unr(uh, uf);
456 }
457 }
458 }
459
460 /*
461 * See if a given unr should be collapsed with a neighbor.
462 *
463 * NB: called from alloc_unr(), no new memory allocation allowed.
464 */
465 static void
466 collapse_unr(struct unrhdr *uh, struct unr *up)
467 {
468 struct unr *upp;
469 struct unrb *ub;
470
471 /* If bitmap is all set or clear, change it to runlength */
472 if (is_bitmap(uh, up)) {
473 ub = up->ptr;
474 if (ub->busy == up->len) {
475 delete_unr(uh, up->ptr);
476 up->ptr = uh;
477 } else if (ub->busy == 0) {
478 delete_unr(uh, up->ptr);
479 up->ptr = NULL;
480 }
481 }
482
483 /* If nothing left in runlength, delete it */
484 if (up->len == 0) {
485 upp = TAILQ_PREV(up, unrhd, list);
486 if (upp == NULL)
487 upp = TAILQ_NEXT(up, list);
488 TAILQ_REMOVE(&uh->head, up, list);
489 delete_unr(uh, up);
490 up = upp;
491 }
492
493 /* If we have "hot-spot" still, merge with neighbor if possible */
494 if (up != NULL) {
495 upp = TAILQ_PREV(up, unrhd, list);
496 if (upp != NULL && up->ptr == upp->ptr) {
497 up->len += upp->len;
498 TAILQ_REMOVE(&uh->head, upp, list);
499 delete_unr(uh, upp);
500 }
501 upp = TAILQ_NEXT(up, list);
502 if (upp != NULL && up->ptr == upp->ptr) {
503 up->len += upp->len;
504 TAILQ_REMOVE(&uh->head, upp, list);
505 delete_unr(uh, upp);
506 }
507 }
508
509 /* Merge into ->first if possible */
510 upp = TAILQ_FIRST(&uh->head);
511 if (upp != NULL && upp->ptr == uh) {
512 uh->first += upp->len;
513 TAILQ_REMOVE(&uh->head, upp, list);
514 delete_unr(uh, upp);
515 if (up == upp)
516 up = NULL;
517 }
518
519 /* Merge into ->last if possible */
520 upp = TAILQ_LAST(&uh->head, unrhd);
521 if (upp != NULL && upp->ptr == NULL) {
522 uh->last += upp->len;
523 TAILQ_REMOVE(&uh->head, upp, list);
524 delete_unr(uh, upp);
525 if (up == upp)
526 up = NULL;
527 }
528
529 /* Try to make bitmaps */
530 while (optimize_unr(uh))
531 continue;
532 }
533
534 /*
535 * Allocate a free unr.
536 */
537 int
538 alloc_unrl(struct unrhdr *uh)
539 {
540 struct unr *up;
541 struct unrb *ub;
542 u_int x;
543 int y;
544
545 mtx_assert(uh->mtx, MA_OWNED);
546 check_unrhdr(uh, __LINE__);
547 x = uh->low + uh->first;
548
549 up = TAILQ_FIRST(&uh->head);
550
551 /*
552 * If we have an ideal split, just adjust the first+last
553 */
554 if (up == NULL && uh->last > 0) {
555 uh->first++;
556 uh->last--;
557 uh->busy++;
558 return (x);
559 }
560
561 /*
562 * We can always allocate from the first list element, so if we have
563 * nothing on the list, we must have run out of unit numbers.
564 */
565 if (up == NULL)
566 return (-1);
567
568 KASSERT(up->ptr != uh, ("UNR first element is allocated"));
569
570 if (up->ptr == NULL) { /* free run */
571 uh->first++;
572 up->len--;
573 } else { /* bitmap */
574 ub = up->ptr;
575 KASSERT(ub->busy < up->len, ("UNR bitmap confusion"));
576 bit_ffc(ub->map, up->len, &y);
577 KASSERT(y != -1, ("UNR corruption: No clear bit in bitmap."));
578 bit_set(ub->map, y);
579 ub->busy++;
580 x += y;
581 }
582 uh->busy++;
583 collapse_unr(uh, up);
584 return (x);
585 }
586
587 int
588 alloc_unr(struct unrhdr *uh)
589 {
590 int i;
591
592 mtx_lock(uh->mtx);
593 i = alloc_unrl(uh);
594 mtx_unlock(uh->mtx);
595 return (i);
596 }
597
598 /*
599 * Free a unr.
600 *
601 * If we can save unrs by using a bitmap, do so.
602 */
603 static void
604 free_unrl(struct unrhdr *uh, u_int item, void **p1, void **p2)
605 {
606 struct unr *up, *upp, *upn;
607 struct unrb *ub;
608 u_int pl;
609
610 KASSERT(item >= uh->low && item <= uh->high,
611 ("UNR: free_unr(%u) out of range [%u...%u]",
612 item, uh->low, uh->high));
613 check_unrhdr(uh, __LINE__);
614 item -= uh->low;
615 upp = TAILQ_FIRST(&uh->head);
616 /*
617 * Freeing in the ideal split case
618 */
619 if (item + 1 == uh->first && upp == NULL) {
620 uh->last++;
621 uh->first--;
622 uh->busy--;
623 check_unrhdr(uh, __LINE__);
624 return;
625 }
626 /*
627 * Freeing in the ->first section. Create a run starting at the
628 * freed item. The code below will subdivide it.
629 */
630 if (item < uh->first) {
631 up = new_unr(uh, p1, p2);
632 up->ptr = uh;
633 up->len = uh->first - item;
634 TAILQ_INSERT_HEAD(&uh->head, up, list);
635 uh->first -= up->len;
636 }
637
638 item -= uh->first;
639
640 /* Find the item which contains the unit we want to free */
641 TAILQ_FOREACH(up, &uh->head, list) {
642 if (up->len > item)
643 break;
644 item -= up->len;
645 }
646
647 /* Handle bitmap items */
648 if (is_bitmap(uh, up)) {
649 ub = up->ptr;
650
651 KASSERT(bit_test(ub->map, item) != 0,
652 ("UNR: Freeing free item %d (bitmap)\n", item));
653 bit_clear(ub->map, item);
654 uh->busy--;
655 ub->busy--;
656 collapse_unr(uh, up);
657 return;
658 }
659
660 KASSERT(up->ptr == uh, ("UNR Freeing free item %d (run))\n", item));
661
662 /* Just this one left, reap it */
663 if (up->len == 1) {
664 up->ptr = NULL;
665 uh->busy--;
666 collapse_unr(uh, up);
667 return;
668 }
669
670 /* Check if we can shift the item into the previous 'free' run */
671 upp = TAILQ_PREV(up, unrhd, list);
672 if (item == 0 && upp != NULL && upp->ptr == NULL) {
673 upp->len++;
674 up->len--;
675 uh->busy--;
676 collapse_unr(uh, up);
677 return;
678 }
679
680 /* Check if we can shift the item to the next 'free' run */
681 upn = TAILQ_NEXT(up, list);
682 if (item == up->len - 1 && upn != NULL && upn->ptr == NULL) {
683 upn->len++;
684 up->len--;
685 uh->busy--;
686 collapse_unr(uh, up);
687 return;
688 }
689
690 /* Split off the tail end, if any. */
691 pl = up->len - (1 + item);
692 if (pl > 0) {
693 upp = new_unr(uh, p1, p2);
694 upp->ptr = uh;
695 upp->len = pl;
696 TAILQ_INSERT_AFTER(&uh->head, up, upp, list);
697 }
698
699 /* Split off head end, if any */
700 if (item > 0) {
701 upp = new_unr(uh, p1, p2);
702 upp->len = item;
703 upp->ptr = uh;
704 TAILQ_INSERT_BEFORE(up, upp, list);
705 }
706 up->len = 1;
707 up->ptr = NULL;
708 uh->busy--;
709 collapse_unr(uh, up);
710 }
711
712 void
713 free_unr(struct unrhdr *uh, u_int item)
714 {
715 void *p1, *p2;
716
717 p1 = Malloc(sizeof(struct unr));
718 p2 = Malloc(sizeof(struct unr));
719 mtx_lock(uh->mtx);
720 free_unrl(uh, item, &p1, &p2);
721 mtx_unlock(uh->mtx);
722 if (p1 != NULL)
723 Free(p1);
724 if (p2 != NULL)
725 Free(p2);
726 }
727
728 #ifndef _KERNEL /* USERLAND test driver */
729
730 /*
731 * Simple stochastic test driver for the above functions
732 */
733
734 static void
735 print_unr(struct unrhdr *uh, struct unr *up)
736 {
737 u_int x;
738 struct unrb *ub;
739
740 printf(" %p len = %5u ", up, up->len);
741 if (up->ptr == NULL)
742 printf("free\n");
743 else if (up->ptr == uh)
744 printf("alloc\n");
745 else {
746 ub = up->ptr;
747 printf("bitmap(%d) [", ub->busy);
748 for (x = 0; x < up->len; x++) {
749 if (bit_test(ub->map, x))
750 printf("#");
751 else
752 printf(" ");
753 }
754 printf("]\n");
755 }
756 }
757
758 static void
759 print_unrhdr(struct unrhdr *uh)
760 {
761 struct unr *up;
762 u_int x;
763
764 printf(
765 "%p low = %u high = %u first = %u last = %u busy %u chunks = %u\n",
766 uh, uh->low, uh->high, uh->first, uh->last, uh->busy, uh->alloc);
767 x = uh->low + uh->first;
768 TAILQ_FOREACH(up, &uh->head, list) {
769 printf(" from = %5u", x);
770 print_unr(uh, up);
771 if (up->ptr == NULL || up->ptr == uh)
772 x += up->len;
773 else
774 x += NBITS;
775 }
776 }
777
778 /* Number of unrs to test */
779 #define NN 10000
780
781 int
782 main(int argc __unused, const char **argv __unused)
783 {
784 struct unrhdr *uh;
785 u_int i, x, m, j;
786 char a[NN];
787
788 setbuf(stdout, NULL);
789 uh = new_unrhdr(0, NN - 1, NULL);
790 print_unrhdr(uh);
791
792 memset(a, 0, sizeof a);
793
794 fprintf(stderr, "sizeof(struct unr) %d\n", sizeof (struct unr));
795 fprintf(stderr, "sizeof(struct unrb) %d\n", sizeof (struct unrb));
796 fprintf(stderr, "sizeof(struct unrhdr) %d\n", sizeof (struct unrhdr));
797 fprintf(stderr, "NBITS %d\n", NBITS);
798 x = 1;
799 for (m = 0; m < NN * 100; m++) {
800 j = random();
801 i = (j >> 1) % NN;
802 #if 0
803 if (a[i] && (j & 1))
804 continue;
805 #endif
806 if (a[i]) {
807 printf("F %u\n", i);
808 free_unr(uh, i);
809 a[i] = 0;
810 } else {
811 no_alloc = 1;
812 i = alloc_unr(uh);
813 if (i != -1) {
814 a[i] = 1;
815 printf("A %u\n", i);
816 }
817 no_alloc = 0;
818 }
819 if (1) /* XXX: change this for detailed debug printout */
820 print_unrhdr(uh);
821 check_unrhdr(uh, __LINE__);
822 }
823 for (i = 0; i < NN; i++) {
824 if (a[i]) {
825 printf("C %u\n", i);
826 free_unr(uh, i);
827 print_unrhdr(uh);
828 }
829 }
830 print_unrhdr(uh);
831 delete_unrhdr(uh);
832 return (0);
833 }
834 #endif
Cache object: 59d8165f747aff2c2dfbe49f9a5d8e0d
|