xref: /netbsd-src/sys/kern/subr_vmem.c (revision e158e0fadbe71d7ff25a8ad75bed404f45658496)
1 /*	$NetBSD: subr_vmem.c,v 1.118 2024/12/06 19:17:59 riastradh Exp $	*/
2 
3 /*-
4  * Copyright (c)2006,2007,2008,2009 YAMAMOTO Takashi,
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 /*
30  * reference:
31  * -	Magazines and Vmem: Extending the Slab Allocator
32  *	to Many CPUs and Arbitrary Resources
33  *	http://www.usenix.org/event/usenix01/bonwick.html
34  *
35  * locking & the boundary tag pool:
36  * - 	A pool(9) is used for vmem boundary tags
37  * - 	During a pool get call the global vmem_btag_refill_lock is taken,
38  *	to serialize access to the allocation reserve, but no other
39  *	vmem arena locks.
40  * -	During pool_put calls no vmem mutexes are locked.
41  * - 	pool_drain doesn't hold the pool's mutex while releasing memory to
42  * 	its backing therefore no interference with any vmem mutexes.
43  * -	The boundary tag pool is forced to put page headers into pool pages
44  *  	(PR_PHINPAGE) and not off page to avoid pool recursion.
45  *  	(due to sizeof(bt_t) it should be the case anyway)
46  */
47 
48 #include <sys/cdefs.h>
49 __KERNEL_RCSID(0, "$NetBSD: subr_vmem.c,v 1.118 2024/12/06 19:17:59 riastradh Exp $");
50 
51 #if defined(_KERNEL) && defined(_KERNEL_OPT)
52 #include "opt_ddb.h"
53 #endif /* defined(_KERNEL) && defined(_KERNEL_OPT) */
54 
55 #include <sys/param.h>
56 #include <sys/types.h>
57 
58 #include <sys/bitops.h>
59 #include <sys/hash.h>
60 #include <sys/queue.h>
61 
62 #if defined(_KERNEL)
63 
64 #include <sys/atomic.h>
65 #include <sys/callout.h>
66 #include <sys/kernel.h>	/* hz */
67 #include <sys/kmem.h>
68 #include <sys/pool.h>
69 #include <sys/sdt.h>
70 #include <sys/systm.h>
71 #include <sys/vmem.h>
72 #include <sys/vmem_impl.h>
73 #include <sys/workqueue.h>
74 
75 #include <uvm/uvm.h>
76 #include <uvm/uvm_extern.h>
77 #include <uvm/uvm_km.h>
78 #include <uvm/uvm_page.h>
79 #include <uvm/uvm_pdaemon.h>
80 
81 #else /* defined(_KERNEL) */
82 
83 #include <assert.h>
84 #include <errno.h>
85 #include <stdio.h>
86 #include <stdlib.h>
87 #include <string.h>
88 
89 #include "../sys/vmem.h"
90 #include "../sys/vmem_impl.h"
91 
92 #define	SET_ERROR(E)	(E)
93 
94 #endif /* defined(_KERNEL) */
95 
96 #if defined(_KERNEL)
97 
98 #include <sys/evcnt.h>
99 
100 #define VMEM_EVCNT_DEFINE(name) \
101 struct evcnt vmem_evcnt_##name = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, \
102     "vmem", #name); \
103 EVCNT_ATTACH_STATIC(vmem_evcnt_##name)
104 #define VMEM_EVCNT_INCR(ev)	(vmem_evcnt_##ev.ev_count++)
105 #define VMEM_EVCNT_DECR(ev)	(vmem_evcnt_##ev.ev_count--)
106 
107 VMEM_EVCNT_DEFINE(static_bt_count);
108 VMEM_EVCNT_DEFINE(static_bt_inuse);
109 
110 #define	VMEM_CONDVAR_INIT(vm, wchan)	cv_init(&vm->vm_cv, wchan)
111 #define	VMEM_CONDVAR_DESTROY(vm)	cv_destroy(&vm->vm_cv)
112 #define	VMEM_CONDVAR_WAIT(vm)		cv_wait(&vm->vm_cv, &vm->vm_lock)
113 #define	VMEM_CONDVAR_BROADCAST(vm)	cv_broadcast(&vm->vm_cv)
114 
115 #else /* defined(_KERNEL) */
116 
117 #define VMEM_EVCNT_INCR(ev)	__nothing
118 #define VMEM_EVCNT_DECR(ev)	__nothing
119 
120 #define	VMEM_CONDVAR_INIT(vm, wchan)	__nothing
121 #define	VMEM_CONDVAR_DESTROY(vm)	__nothing
122 #define	VMEM_CONDVAR_WAIT(vm)		__nothing
123 #define	VMEM_CONDVAR_BROADCAST(vm)	__nothing
124 
125 #define	UNITTEST
126 #define	KASSERT(a)		assert(a)
127 #define	KASSERTMSG(a, m, ...)	assert(a)
128 #define	mutex_init(a, b, c)	__nothing
129 #define	mutex_destroy(a)	__nothing
130 #define	mutex_enter(a)		__nothing
131 #define	mutex_tryenter(a)	true
132 #define	mutex_exit(a)		__nothing
133 #define	mutex_owned(a)		true
134 #define	ASSERT_SLEEPABLE()	__nothing
135 #define	panic(...)		(printf(__VA_ARGS__), abort())
136 
137 #endif /* defined(_KERNEL) */
138 
139 #if defined(VMEM_SANITY)
140 static void vmem_check(vmem_t *);
141 #else /* defined(VMEM_SANITY) */
142 #define vmem_check(vm)	__nothing
143 #endif /* defined(VMEM_SANITY) */
144 
145 #define	VMEM_HASHSIZE_MIN	1	/* XXX */
146 #define	VMEM_HASHSIZE_MAX	65536	/* XXX */
147 #define	VMEM_HASHSIZE_INIT	1
148 
149 #define	VM_FITMASK	(VM_BESTFIT | VM_INSTANTFIT)
150 
151 #if defined(_KERNEL)
152 static bool vmem_bootstrapped = false;
153 static kmutex_t vmem_list_lock;
154 static LIST_HEAD(, vmem) vmem_list = LIST_HEAD_INITIALIZER(vmem_list);
155 #endif /* defined(_KERNEL) */
156 
157 /* ---- misc */
158 
159 #define	VMEM_LOCK(vm)		mutex_enter(&(vm)->vm_lock)
160 #define	VMEM_TRYLOCK(vm)	mutex_tryenter(&(vm)->vm_lock)
161 #define	VMEM_UNLOCK(vm)		mutex_exit(&(vm)->vm_lock)
162 #define	VMEM_LOCK_INIT(vm, ipl)	mutex_init(&(vm)->vm_lock, MUTEX_DEFAULT, (ipl))
163 #define	VMEM_LOCK_DESTROY(vm)	mutex_destroy(&(vm)->vm_lock)
164 #define	VMEM_ASSERT_LOCKED(vm)	KASSERT(mutex_owned(&(vm)->vm_lock))
165 
166 #define	VMEM_ALIGNUP(addr, align) \
167 	(-(-(addr) & -(align)))
168 
169 #define	VMEM_CROSS_P(addr1, addr2, boundary) \
170 	((((addr1) ^ (addr2)) & -(boundary)) != 0)
171 
172 #define	ORDER2SIZE(order)	((vmem_size_t)1 << (order))
173 #define	SIZE2ORDER(size)	((int)ilog2(size))
174 
175 static void
176 vmem_kick_pdaemon(void)
177 {
178 #if defined(_KERNEL)
179 	uvm_kick_pdaemon();
180 #endif
181 }
182 
183 static void vmem_xfree_bt(vmem_t *, bt_t *);
184 
185 #if !defined(_KERNEL)
186 #define	xmalloc(sz, flags)	malloc(sz)
187 #define	xfree(p, sz)		free(p)
188 #define	bt_alloc(vm, flags)	malloc(sizeof(bt_t))
189 #define	bt_free(vm, bt)		free(bt)
190 #define	bt_freetrim(vm, l)	__nothing
191 #else /* defined(_KERNEL) */
192 
193 #define	xmalloc(sz, flags) \
194     kmem_alloc(sz, ((flags) & VM_SLEEP) ? KM_SLEEP : KM_NOSLEEP);
195 #define	xfree(p, sz)		kmem_free(p, sz);
196 
197 /*
198  * BT_RESERVE calculation:
199  * we allocate memory for boundary tags with vmem; therefore we have
200  * to keep a reserve of bts used to allocated memory for bts.
201  * This reserve is 4 for each arena involved in allocating vmems memory.
202  * BT_MAXFREE: don't cache excessive counts of bts in arenas
203  */
204 #define STATIC_BT_COUNT 200
205 #define BT_MINRESERVE 4
206 #define BT_MAXFREE 64
207 
208 static struct vmem_btag static_bts[STATIC_BT_COUNT];
209 static int static_bt_count = STATIC_BT_COUNT;
210 
211 static struct vmem kmem_va_meta_arena_store;
212 vmem_t *kmem_va_meta_arena;
213 static struct vmem kmem_meta_arena_store;
214 vmem_t *kmem_meta_arena = NULL;
215 
216 static kmutex_t vmem_btag_refill_lock;
217 static kmutex_t vmem_btag_lock;
218 static LIST_HEAD(, vmem_btag) vmem_btag_freelist;
219 static size_t vmem_btag_freelist_count = 0;
220 static struct pool vmem_btag_pool;
221 static bool vmem_btag_pool_initialized __read_mostly;
222 
223 /* ---- boundary tag */
224 
225 static int bt_refill(vmem_t *vm);
226 static int bt_refill_locked(vmem_t *vm);
227 
228 static void *
229 pool_page_alloc_vmem_meta(struct pool *pp, int flags)
230 {
231 	const vm_flag_t vflags = (flags & PR_WAITOK) ? VM_SLEEP: VM_NOSLEEP;
232 	vmem_addr_t va;
233 	int ret;
234 
235 	ret = vmem_alloc(kmem_meta_arena, pp->pr_alloc->pa_pagesz,
236 	    (vflags & ~VM_FITMASK) | VM_INSTANTFIT | VM_POPULATING, &va);
237 
238 	return ret ? NULL : (void *)va;
239 }
240 
241 static void
242 pool_page_free_vmem_meta(struct pool *pp, void *v)
243 {
244 
245 	vmem_free(kmem_meta_arena, (vmem_addr_t)v, pp->pr_alloc->pa_pagesz);
246 }
247 
248 /* allocator for vmem-pool metadata */
249 struct pool_allocator pool_allocator_vmem_meta = {
250 	.pa_alloc = pool_page_alloc_vmem_meta,
251 	.pa_free = pool_page_free_vmem_meta,
252 	.pa_pagesz = 0
253 };
254 
255 static int
256 bt_refill_locked(vmem_t *vm)
257 {
258 	bt_t *bt;
259 
260 	VMEM_ASSERT_LOCKED(vm);
261 
262 	if (vm->vm_nfreetags > BT_MINRESERVE) {
263 		return 0;
264 	}
265 
266 	mutex_enter(&vmem_btag_lock);
267 	while (!LIST_EMPTY(&vmem_btag_freelist) &&
268 	    vm->vm_nfreetags <= BT_MINRESERVE &&
269 	    (vm->vm_flags & VM_PRIVTAGS) == 0) {
270 		bt = LIST_FIRST(&vmem_btag_freelist);
271 		LIST_REMOVE(bt, bt_freelist);
272 		bt->bt_flags = 0;
273 		LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
274 		vm->vm_nfreetags++;
275 		vmem_btag_freelist_count--;
276 		VMEM_EVCNT_INCR(static_bt_inuse);
277 	}
278 	mutex_exit(&vmem_btag_lock);
279 
280 	while (vm->vm_nfreetags <= BT_MINRESERVE) {
281 		VMEM_UNLOCK(vm);
282 		KASSERT(vmem_btag_pool_initialized);
283 		mutex_enter(&vmem_btag_refill_lock);
284 		bt = pool_get(&vmem_btag_pool, PR_NOWAIT);
285 		mutex_exit(&vmem_btag_refill_lock);
286 		VMEM_LOCK(vm);
287 		if (bt == NULL)
288 			break;
289 		bt->bt_flags = 0;
290 		LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
291 		vm->vm_nfreetags++;
292 	}
293 
294 	if (vm->vm_nfreetags <= BT_MINRESERVE) {
295 		return SET_ERROR(ENOMEM);
296 	}
297 
298 	if (kmem_meta_arena != NULL) {
299 		VMEM_UNLOCK(vm);
300 		(void)bt_refill(kmem_arena);
301 		(void)bt_refill(kmem_va_meta_arena);
302 		(void)bt_refill(kmem_meta_arena);
303 		VMEM_LOCK(vm);
304 	}
305 
306 	return 0;
307 }
308 
309 static int
310 bt_refill(vmem_t *vm)
311 {
312 	int rv;
313 
314 	VMEM_LOCK(vm);
315 	rv = bt_refill_locked(vm);
316 	VMEM_UNLOCK(vm);
317 	return rv;
318 }
319 
320 static bt_t *
321 bt_alloc(vmem_t *vm, vm_flag_t flags)
322 {
323 	bt_t *bt;
324 
325 	VMEM_ASSERT_LOCKED(vm);
326 
327 	while (vm->vm_nfreetags <= BT_MINRESERVE && (flags & VM_POPULATING) == 0) {
328 		if (bt_refill_locked(vm)) {
329 			if ((flags & VM_NOSLEEP) != 0) {
330 				return NULL;
331 			}
332 
333 			/*
334 			 * It would be nice to wait for something specific here
335 			 * but there are multiple ways that a retry could
336 			 * succeed and we can't wait for multiple things
337 			 * simultaneously.  So we'll just sleep for an arbitrary
338 			 * short period of time and retry regardless.
339 			 * This should be a very rare case.
340 			 */
341 
342 			vmem_kick_pdaemon();
343 			kpause("btalloc", false, 1, &vm->vm_lock);
344 		}
345 	}
346 	bt = LIST_FIRST(&vm->vm_freetags);
347 	LIST_REMOVE(bt, bt_freelist);
348 	vm->vm_nfreetags--;
349 
350 	return bt;
351 }
352 
353 static void
354 bt_free(vmem_t *vm, bt_t *bt)
355 {
356 
357 	VMEM_ASSERT_LOCKED(vm);
358 
359 	LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
360 	vm->vm_nfreetags++;
361 }
362 
363 static void
364 bt_freetrim(vmem_t *vm, int freelimit)
365 {
366 	bt_t *bt, *next_bt;
367 	LIST_HEAD(, vmem_btag) tofree;
368 
369 	VMEM_ASSERT_LOCKED(vm);
370 
371 	LIST_INIT(&tofree);
372 
373 	LIST_FOREACH_SAFE(bt, &vm->vm_freetags, bt_freelist, next_bt) {
374 		if (vm->vm_nfreetags <= freelimit) {
375 			break;
376 		}
377 		if (bt->bt_flags & BT_F_PRIVATE) {
378 			continue;
379 		}
380 		LIST_REMOVE(bt, bt_freelist);
381 		vm->vm_nfreetags--;
382 		if (bt >= static_bts
383 		    && bt < &static_bts[STATIC_BT_COUNT]) {
384 			mutex_enter(&vmem_btag_lock);
385 			LIST_INSERT_HEAD(&vmem_btag_freelist, bt, bt_freelist);
386 			vmem_btag_freelist_count++;
387 			mutex_exit(&vmem_btag_lock);
388 			VMEM_EVCNT_DECR(static_bt_inuse);
389 		} else {
390 			LIST_INSERT_HEAD(&tofree, bt, bt_freelist);
391 		}
392 	}
393 
394 	VMEM_UNLOCK(vm);
395 	while (!LIST_EMPTY(&tofree)) {
396 		bt = LIST_FIRST(&tofree);
397 		LIST_REMOVE(bt, bt_freelist);
398 		pool_put(&vmem_btag_pool, bt);
399 	}
400 }
401 
402 /*
403  * Add private boundary tags (statically-allocated by the caller)
404  * to a vmem arena's free tag list.
405  */
406 void
407 vmem_add_bts(vmem_t *vm, struct vmem_btag *bts, unsigned int nbts)
408 {
409 	VMEM_LOCK(vm);
410 	while (nbts != 0) {
411 		bts->bt_flags = BT_F_PRIVATE;
412 		LIST_INSERT_HEAD(&vm->vm_freetags, bts, bt_freelist);
413 		vm->vm_nfreetags++;
414 		bts++;
415 		nbts--;
416 	}
417 	VMEM_UNLOCK(vm);
418 }
419 #endif	/* defined(_KERNEL) */
420 
421 /*
422  * freelist[0] ... [1, 1]
423  * freelist[1] ... [2, 3]
424  * freelist[2] ... [4, 7]
425  * freelist[3] ... [8, 15]
426  *  :
427  * freelist[n] ... [(1 << n), (1 << (n + 1)) - 1]
428  *  :
429  */
430 
431 static struct vmem_freelist *
432 bt_freehead_tofree(vmem_t *vm, vmem_size_t size)
433 {
434 	const vmem_size_t qsize = size >> vm->vm_quantum_shift;
435 	const int idx = SIZE2ORDER(qsize);
436 
437 	KASSERT(size != 0);
438 	KASSERT(qsize != 0);
439 	KASSERT((size & vm->vm_quantum_mask) == 0);
440 	KASSERT(idx >= 0);
441 	KASSERT(idx < VMEM_MAXORDER);
442 
443 	return &vm->vm_freelist[idx];
444 }
445 
446 /*
447  * bt_freehead_toalloc: return the freelist for the given size and allocation
448  * strategy.
449  *
450  * for VM_INSTANTFIT, return the list in which any blocks are large enough
451  * for the requested size.  otherwise, return the list which can have blocks
452  * large enough for the requested size.
453  */
454 
455 static struct vmem_freelist *
456 bt_freehead_toalloc(vmem_t *vm, vmem_size_t size, vm_flag_t strat)
457 {
458 	const vmem_size_t qsize = size >> vm->vm_quantum_shift;
459 	int idx = SIZE2ORDER(qsize);
460 
461 	KASSERT(size != 0);
462 	KASSERT(qsize != 0);
463 	KASSERT((size & vm->vm_quantum_mask) == 0);
464 
465 	if (strat == VM_INSTANTFIT && ORDER2SIZE(idx) != qsize) {
466 		idx++;
467 		/* check too large request? */
468 	}
469 	KASSERT(idx >= 0);
470 	KASSERT(idx < VMEM_MAXORDER);
471 
472 	return &vm->vm_freelist[idx];
473 }
474 
475 /* ---- boundary tag hash */
476 
477 static struct vmem_hashlist *
478 bt_hashhead(vmem_t *vm, vmem_addr_t addr)
479 {
480 	struct vmem_hashlist *list;
481 	unsigned int hash;
482 
483 	hash = hash32_buf(&addr, sizeof(addr), HASH32_BUF_INIT);
484 	list = &vm->vm_hashlist[hash & vm->vm_hashmask];
485 
486 	return list;
487 }
488 
489 static bt_t *
490 bt_lookupbusy(vmem_t *vm, vmem_addr_t addr)
491 {
492 	struct vmem_hashlist *list;
493 	bt_t *bt;
494 
495 	list = bt_hashhead(vm, addr);
496 	LIST_FOREACH(bt, list, bt_hashlist) {
497 		if (bt->bt_start == addr) {
498 			break;
499 		}
500 	}
501 
502 	return bt;
503 }
504 
505 static void
506 bt_rembusy(vmem_t *vm, bt_t *bt)
507 {
508 
509 	KASSERT(vm->vm_nbusytag > 0);
510 	vm->vm_inuse -= bt->bt_size;
511 	vm->vm_nbusytag--;
512 	LIST_REMOVE(bt, bt_hashlist);
513 }
514 
515 static void
516 bt_insbusy(vmem_t *vm, bt_t *bt)
517 {
518 	struct vmem_hashlist *list;
519 
520 	KASSERT(bt->bt_type == BT_TYPE_BUSY);
521 
522 	list = bt_hashhead(vm, bt->bt_start);
523 	LIST_INSERT_HEAD(list, bt, bt_hashlist);
524 	if (++vm->vm_nbusytag > vm->vm_maxbusytag) {
525 		vm->vm_maxbusytag = vm->vm_nbusytag;
526 	}
527 	vm->vm_inuse += bt->bt_size;
528 }
529 
530 /* ---- boundary tag list */
531 
532 static void
533 bt_remseg(vmem_t *vm, bt_t *bt)
534 {
535 
536 	TAILQ_REMOVE(&vm->vm_seglist, bt, bt_seglist);
537 }
538 
539 static void
540 bt_insseg(vmem_t *vm, bt_t *bt, bt_t *prev)
541 {
542 
543 	TAILQ_INSERT_AFTER(&vm->vm_seglist, prev, bt, bt_seglist);
544 }
545 
546 static void
547 bt_insseg_tail(vmem_t *vm, bt_t *bt)
548 {
549 
550 	TAILQ_INSERT_TAIL(&vm->vm_seglist, bt, bt_seglist);
551 }
552 
553 static void
554 bt_remfree(vmem_t *vm, bt_t *bt)
555 {
556 
557 	KASSERT(bt->bt_type == BT_TYPE_FREE);
558 
559 	LIST_REMOVE(bt, bt_freelist);
560 }
561 
562 static void
563 bt_insfree(vmem_t *vm, bt_t *bt)
564 {
565 	struct vmem_freelist *list;
566 
567 	list = bt_freehead_tofree(vm, bt->bt_size);
568 	LIST_INSERT_HEAD(list, bt, bt_freelist);
569 }
570 
571 /* ---- vmem internal functions */
572 
573 #if defined(QCACHE)
574 static inline vm_flag_t
575 prf_to_vmf(int prflags)
576 {
577 	vm_flag_t vmflags;
578 
579 	KASSERT((prflags & ~(PR_LIMITFAIL | PR_WAITOK | PR_NOWAIT)) == 0);
580 	if ((prflags & PR_WAITOK) != 0) {
581 		vmflags = VM_SLEEP;
582 	} else {
583 		vmflags = VM_NOSLEEP;
584 	}
585 	return vmflags;
586 }
587 
588 static inline int
589 vmf_to_prf(vm_flag_t vmflags)
590 {
591 	int prflags;
592 
593 	if ((vmflags & VM_SLEEP) != 0) {
594 		prflags = PR_WAITOK;
595 	} else {
596 		prflags = PR_NOWAIT;
597 	}
598 	return prflags;
599 }
600 
601 static size_t
602 qc_poolpage_size(size_t qcache_max)
603 {
604 	int i;
605 
606 	for (i = 0; ORDER2SIZE(i) <= qcache_max * 3; i++) {
607 		/* nothing */
608 	}
609 	return ORDER2SIZE(i);
610 }
611 
612 static void *
613 qc_poolpage_alloc(struct pool *pool, int prflags)
614 {
615 	qcache_t *qc = QC_POOL_TO_QCACHE(pool);
616 	vmem_t *vm = qc->qc_vmem;
617 	vmem_addr_t addr;
618 
619 	if (vmem_alloc(vm, pool->pr_alloc->pa_pagesz,
620 	    prf_to_vmf(prflags) | VM_INSTANTFIT, &addr) != 0)
621 		return NULL;
622 	return (void *)addr;
623 }
624 
625 static void
626 qc_poolpage_free(struct pool *pool, void *addr)
627 {
628 	qcache_t *qc = QC_POOL_TO_QCACHE(pool);
629 	vmem_t *vm = qc->qc_vmem;
630 
631 	vmem_free(vm, (vmem_addr_t)addr, pool->pr_alloc->pa_pagesz);
632 }
633 
634 static void
635 qc_init(vmem_t *vm, size_t qcache_max, int ipl)
636 {
637 	qcache_t *prevqc;
638 	struct pool_allocator *pa;
639 	int qcache_idx_max;
640 	int i;
641 
642 	KASSERT((qcache_max & vm->vm_quantum_mask) == 0);
643 	if (qcache_max > (VMEM_QCACHE_IDX_MAX << vm->vm_quantum_shift)) {
644 		qcache_max = VMEM_QCACHE_IDX_MAX << vm->vm_quantum_shift;
645 	}
646 	vm->vm_qcache_max = qcache_max;
647 	pa = &vm->vm_qcache_allocator;
648 	memset(pa, 0, sizeof(*pa));
649 	pa->pa_alloc = qc_poolpage_alloc;
650 	pa->pa_free = qc_poolpage_free;
651 	pa->pa_pagesz = qc_poolpage_size(qcache_max);
652 
653 	qcache_idx_max = qcache_max >> vm->vm_quantum_shift;
654 	prevqc = NULL;
655 	for (i = qcache_idx_max; i > 0; i--) {
656 		qcache_t *qc = &vm->vm_qcache_store[i - 1];
657 		size_t size = i << vm->vm_quantum_shift;
658 		pool_cache_t pc;
659 
660 		qc->qc_vmem = vm;
661 		snprintf(qc->qc_name, sizeof(qc->qc_name), "%s-%zu",
662 		    vm->vm_name, size);
663 
664 		pc = pool_cache_init(size,
665 		    ORDER2SIZE(vm->vm_quantum_shift), 0,
666 		    PR_NOALIGN | PR_NOTOUCH | PR_RECURSIVE /* XXX */,
667 		    qc->qc_name, pa, ipl, NULL, NULL, NULL);
668 
669 		KASSERT(pc);
670 
671 		qc->qc_cache = pc;
672 		KASSERT(qc->qc_cache != NULL);	/* XXX */
673 		if (prevqc != NULL &&
674 		    qc->qc_cache->pc_pool.pr_itemsperpage ==
675 		    prevqc->qc_cache->pc_pool.pr_itemsperpage) {
676 			pool_cache_destroy(qc->qc_cache);
677 			vm->vm_qcache[i - 1] = prevqc;
678 			continue;
679 		}
680 		qc->qc_cache->pc_pool.pr_qcache = qc;
681 		vm->vm_qcache[i - 1] = qc;
682 		prevqc = qc;
683 	}
684 }
685 
686 static void
687 qc_destroy(vmem_t *vm)
688 {
689 	const qcache_t *prevqc;
690 	int i;
691 	int qcache_idx_max;
692 
693 	qcache_idx_max = vm->vm_qcache_max >> vm->vm_quantum_shift;
694 	prevqc = NULL;
695 	for (i = 0; i < qcache_idx_max; i++) {
696 		qcache_t *qc = vm->vm_qcache[i];
697 
698 		if (prevqc == qc) {
699 			continue;
700 		}
701 		pool_cache_destroy(qc->qc_cache);
702 		prevqc = qc;
703 	}
704 }
705 #endif
706 
707 #if defined(_KERNEL)
708 static void
709 vmem_bootstrap(void)
710 {
711 
712 	mutex_init(&vmem_list_lock, MUTEX_DEFAULT, IPL_NONE);
713 	mutex_init(&vmem_btag_lock, MUTEX_DEFAULT, IPL_VM);
714 	mutex_init(&vmem_btag_refill_lock, MUTEX_DEFAULT, IPL_VM);
715 
716 	while (static_bt_count-- > 0) {
717 		bt_t *bt = &static_bts[static_bt_count];
718 		LIST_INSERT_HEAD(&vmem_btag_freelist, bt, bt_freelist);
719 		VMEM_EVCNT_INCR(static_bt_count);
720 		vmem_btag_freelist_count++;
721 	}
722 	vmem_bootstrapped = TRUE;
723 }
724 
725 void
726 vmem_subsystem_init(vmem_t *vm)
727 {
728 
729 	kmem_va_meta_arena = vmem_init(&kmem_va_meta_arena_store, "vmem-va",
730 	    0, 0, PAGE_SIZE, vmem_alloc, vmem_free, vm,
731 	    0, VM_NOSLEEP | VM_BOOTSTRAP | VM_LARGEIMPORT,
732 	    IPL_VM);
733 
734 	kmem_meta_arena = vmem_init(&kmem_meta_arena_store, "vmem-meta",
735 	    0, 0, PAGE_SIZE,
736 	    uvm_km_kmem_alloc, uvm_km_kmem_free, kmem_va_meta_arena,
737 	    0, VM_NOSLEEP | VM_BOOTSTRAP, IPL_VM);
738 
739 	pool_init(&vmem_btag_pool, sizeof(bt_t), coherency_unit, 0,
740 	    PR_PHINPAGE, "vmembt", &pool_allocator_vmem_meta, IPL_VM);
741 	vmem_btag_pool_initialized = true;
742 }
743 #endif /* defined(_KERNEL) */
744 
745 static int
746 vmem_add1(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, vm_flag_t flags,
747     int spanbttype)
748 {
749 	bt_t *btspan;
750 	bt_t *btfree;
751 
752 	VMEM_ASSERT_LOCKED(vm);
753 	KASSERT((flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
754 	KASSERT((~flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
755 	KASSERT(spanbttype == BT_TYPE_SPAN ||
756 	    spanbttype == BT_TYPE_SPAN_STATIC);
757 
758 	btspan = bt_alloc(vm, flags);
759 	if (btspan == NULL) {
760 		return SET_ERROR(ENOMEM);
761 	}
762 	btfree = bt_alloc(vm, flags);
763 	if (btfree == NULL) {
764 		bt_free(vm, btspan);
765 		return SET_ERROR(ENOMEM);
766 	}
767 
768 	btspan->bt_type = spanbttype;
769 	btspan->bt_start = addr;
770 	btspan->bt_size = size;
771 
772 	btfree->bt_type = BT_TYPE_FREE;
773 	btfree->bt_start = addr;
774 	btfree->bt_size = size;
775 
776 	bt_insseg_tail(vm, btspan);
777 	bt_insseg(vm, btfree, btspan);
778 	bt_insfree(vm, btfree);
779 	vm->vm_size += size;
780 
781 	return 0;
782 }
783 
784 static void
785 vmem_destroy1(vmem_t *vm)
786 {
787 
788 #if defined(QCACHE)
789 	qc_destroy(vm);
790 #endif /* defined(QCACHE) */
791 	VMEM_LOCK(vm);
792 
793 	for (int i = 0; i < vm->vm_hashsize; i++) {
794 		bt_t *bt;
795 
796 		while ((bt = LIST_FIRST(&vm->vm_hashlist[i])) != NULL) {
797 			KASSERT(bt->bt_type == BT_TYPE_SPAN_STATIC);
798 			LIST_REMOVE(bt, bt_hashlist);
799 			bt_free(vm, bt);
800 		}
801 	}
802 
803 	/* bt_freetrim() drops the lock. */
804 	bt_freetrim(vm, 0);
805 	if (vm->vm_hashlist != &vm->vm_hash0) {
806 		xfree(vm->vm_hashlist,
807 		    sizeof(struct vmem_hashlist) * vm->vm_hashsize);
808 	}
809 
810 	VMEM_CONDVAR_DESTROY(vm);
811 	VMEM_LOCK_DESTROY(vm);
812 	xfree(vm, sizeof(*vm));
813 }
814 
815 static int
816 vmem_import(vmem_t *vm, vmem_size_t size, vm_flag_t flags)
817 {
818 	vmem_addr_t addr;
819 	int rc;
820 
821 	VMEM_ASSERT_LOCKED(vm);
822 
823 	if (vm->vm_importfn == NULL) {
824 		return SET_ERROR(EINVAL);
825 	}
826 
827 	if (vm->vm_flags & VM_LARGEIMPORT) {
828 		size *= 16;
829 	}
830 
831 	VMEM_UNLOCK(vm);
832 	if (vm->vm_flags & VM_XIMPORT) {
833 		rc = __FPTRCAST(vmem_ximport_t *, vm->vm_importfn)(vm->vm_arg,
834 		    size, &size, flags, &addr);
835 	} else {
836 		rc = (vm->vm_importfn)(vm->vm_arg, size, flags, &addr);
837 	}
838 	VMEM_LOCK(vm);
839 
840 	if (rc) {
841 		return SET_ERROR(ENOMEM);
842 	}
843 
844 	if (vmem_add1(vm, addr, size, flags, BT_TYPE_SPAN) != 0) {
845 		VMEM_UNLOCK(vm);
846 		(*vm->vm_releasefn)(vm->vm_arg, addr, size);
847 		VMEM_LOCK(vm);
848 		return SET_ERROR(ENOMEM);
849 	}
850 
851 	return 0;
852 }
853 
854 #if defined(_KERNEL)
855 static int
856 vmem_rehash(vmem_t *vm, size_t newhashsize, vm_flag_t flags)
857 {
858 	bt_t *bt;
859 	int i;
860 	struct vmem_hashlist *newhashlist;
861 	struct vmem_hashlist *oldhashlist;
862 	size_t oldhashsize;
863 
864 	KASSERT(newhashsize > 0);
865 
866 	/* Round hash size up to a power of 2. */
867 	newhashsize = 1 << (ilog2(newhashsize) + 1);
868 
869 	newhashlist =
870 	    xmalloc(sizeof(struct vmem_hashlist) * newhashsize, flags);
871 	if (newhashlist == NULL) {
872 		return SET_ERROR(ENOMEM);
873 	}
874 	for (i = 0; i < newhashsize; i++) {
875 		LIST_INIT(&newhashlist[i]);
876 	}
877 
878 	VMEM_LOCK(vm);
879 	/* Decay back to a small hash slowly. */
880 	if (vm->vm_maxbusytag >= 2) {
881 		vm->vm_maxbusytag = vm->vm_maxbusytag / 2 - 1;
882 		if (vm->vm_nbusytag > vm->vm_maxbusytag) {
883 			vm->vm_maxbusytag = vm->vm_nbusytag;
884 		}
885 	} else {
886 		vm->vm_maxbusytag = vm->vm_nbusytag;
887 	}
888 	oldhashlist = vm->vm_hashlist;
889 	oldhashsize = vm->vm_hashsize;
890 	vm->vm_hashlist = newhashlist;
891 	vm->vm_hashsize = newhashsize;
892 	vm->vm_hashmask = newhashsize - 1;
893 	if (oldhashlist == NULL) {
894 		VMEM_UNLOCK(vm);
895 		return 0;
896 	}
897 	for (i = 0; i < oldhashsize; i++) {
898 		while ((bt = LIST_FIRST(&oldhashlist[i])) != NULL) {
899 			bt_rembusy(vm, bt); /* XXX */
900 			bt_insbusy(vm, bt);
901 		}
902 	}
903 	VMEM_UNLOCK(vm);
904 
905 	if (oldhashlist != &vm->vm_hash0) {
906 		xfree(oldhashlist,
907 		    sizeof(struct vmem_hashlist) * oldhashsize);
908 	}
909 
910 	return 0;
911 }
912 #endif /* _KERNEL */
913 
914 /*
915  * vmem_fit: check if a bt can satisfy the given restrictions.
916  *
917  * it's a caller's responsibility to ensure the region is big enough
918  * before calling us.
919  */
920 
921 static int
922 vmem_fit(const bt_t *bt, vmem_size_t size, vmem_size_t align,
923     vmem_size_t phase, vmem_size_t nocross,
924     vmem_addr_t minaddr, vmem_addr_t maxaddr, vmem_addr_t *addrp)
925 {
926 	vmem_addr_t start;
927 	vmem_addr_t end;
928 
929 	KASSERT(size > 0);
930 	KASSERT(bt->bt_size >= size); /* caller's responsibility */
931 
932 	/*
933 	 * XXX assumption: vmem_addr_t and vmem_size_t are
934 	 * unsigned integer of the same size.
935 	 */
936 
937 	start = bt->bt_start;
938 	if (start < minaddr) {
939 		start = minaddr;
940 	}
941 	end = BT_END(bt);
942 	if (end > maxaddr) {
943 		end = maxaddr;
944 	}
945 	if (start > end) {
946 		return SET_ERROR(ENOMEM);
947 	}
948 
949 	start = VMEM_ALIGNUP(start - phase, align) + phase;
950 	if (start < bt->bt_start) {
951 		start += align;
952 	}
953 	if (VMEM_CROSS_P(start, start + size - 1, nocross)) {
954 		KASSERT(align < nocross);
955 		start = VMEM_ALIGNUP(start - phase, nocross) + phase;
956 	}
957 	if (start <= end && end - start >= size - 1) {
958 		KASSERT((start & (align - 1)) == phase);
959 		KASSERT(!VMEM_CROSS_P(start, start + size - 1, nocross));
960 		KASSERT(minaddr <= start);
961 		KASSERT(maxaddr == 0 || start + size - 1 <= maxaddr);
962 		KASSERT(bt->bt_start <= start);
963 		KASSERT(BT_END(bt) - start >= size - 1);
964 		*addrp = start;
965 		return 0;
966 	}
967 	return SET_ERROR(ENOMEM);
968 }
969 
970 /* ---- vmem API */
971 
972 /*
973  * vmem_init: creates a vmem arena.
974  */
975 
976 vmem_t *
977 vmem_init(vmem_t *vm, const char *name,
978     vmem_addr_t base, vmem_size_t size, vmem_size_t quantum,
979     vmem_import_t *importfn, vmem_release_t *releasefn,
980     vmem_t *arg, vmem_size_t qcache_max, vm_flag_t flags, int ipl)
981 {
982 	int i;
983 
984 	KASSERT((flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
985 	KASSERT((~flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
986 	KASSERT(quantum > 0);
987 	KASSERT(powerof2(quantum));
988 
989 	/*
990 	 * If private tags are going to be used, they must
991 	 * be added to the arena before the first span is
992 	 * added.
993 	 */
994 	KASSERT((flags & VM_PRIVTAGS) == 0 || size == 0);
995 
996 #if defined(_KERNEL)
997 	/* XXX: SMP, we get called early... */
998 	if (!vmem_bootstrapped) {
999 		vmem_bootstrap();
1000 	}
1001 #endif /* defined(_KERNEL) */
1002 
1003 	if (vm == NULL) {
1004 		vm = xmalloc(sizeof(*vm), flags);
1005 	}
1006 	if (vm == NULL) {
1007 		return NULL;
1008 	}
1009 
1010 	VMEM_CONDVAR_INIT(vm, "vmem");
1011 	VMEM_LOCK_INIT(vm, ipl);
1012 	vm->vm_flags = flags;
1013 	vm->vm_nfreetags = 0;
1014 	LIST_INIT(&vm->vm_freetags);
1015 	strlcpy(vm->vm_name, name, sizeof(vm->vm_name));
1016 	vm->vm_quantum_mask = quantum - 1;
1017 	vm->vm_quantum_shift = SIZE2ORDER(quantum);
1018 	KASSERT(ORDER2SIZE(vm->vm_quantum_shift) == quantum);
1019 	vm->vm_importfn = importfn;
1020 	vm->vm_releasefn = releasefn;
1021 	vm->vm_arg = arg;
1022 	vm->vm_nbusytag = 0;
1023 	vm->vm_maxbusytag = 0;
1024 	vm->vm_size = 0;
1025 	vm->vm_inuse = 0;
1026 #if defined(QCACHE)
1027 	qc_init(vm, qcache_max, ipl);
1028 #endif /* defined(QCACHE) */
1029 
1030 	TAILQ_INIT(&vm->vm_seglist);
1031 	for (i = 0; i < VMEM_MAXORDER; i++) {
1032 		LIST_INIT(&vm->vm_freelist[i]);
1033 	}
1034 	memset(&vm->vm_hash0, 0, sizeof(vm->vm_hash0));
1035 	vm->vm_hashsize = 1;
1036 	vm->vm_hashmask = vm->vm_hashsize - 1;
1037 	vm->vm_hashlist = &vm->vm_hash0;
1038 
1039 	if (size != 0) {
1040 		if (vmem_add(vm, base, size, flags) != 0) {
1041 			vmem_destroy1(vm);
1042 			return NULL;
1043 		}
1044 	}
1045 
1046 #if defined(_KERNEL)
1047 	if (flags & VM_BOOTSTRAP) {
1048 		bt_refill(vm);
1049 	}
1050 
1051 	mutex_enter(&vmem_list_lock);
1052 	LIST_INSERT_HEAD(&vmem_list, vm, vm_alllist);
1053 	mutex_exit(&vmem_list_lock);
1054 #endif /* defined(_KERNEL) */
1055 
1056 	return vm;
1057 }
1058 
1059 
1060 
1061 /*
1062  * vmem_create: create an arena.
1063  *
1064  * => must not be called from interrupt context.
1065  */
1066 
1067 vmem_t *
1068 vmem_create(const char *name, vmem_addr_t base, vmem_size_t size,
1069     vmem_size_t quantum, vmem_import_t *importfn, vmem_release_t *releasefn,
1070     vmem_t *source, vmem_size_t qcache_max, vm_flag_t flags, int ipl)
1071 {
1072 
1073 	KASSERT((flags & (VM_XIMPORT)) == 0);
1074 
1075 	return vmem_init(NULL, name, base, size, quantum,
1076 	    importfn, releasefn, source, qcache_max, flags, ipl);
1077 }
1078 
1079 /*
1080  * vmem_xcreate: create an arena takes alternative import func.
1081  *
1082  * => must not be called from interrupt context.
1083  */
1084 
1085 vmem_t *
1086 vmem_xcreate(const char *name, vmem_addr_t base, vmem_size_t size,
1087     vmem_size_t quantum, vmem_ximport_t *importfn, vmem_release_t *releasefn,
1088     vmem_t *source, vmem_size_t qcache_max, vm_flag_t flags, int ipl)
1089 {
1090 
1091 	KASSERT((flags & (VM_XIMPORT)) == 0);
1092 
1093 	return vmem_init(NULL, name, base, size, quantum,
1094 	    __FPTRCAST(vmem_import_t *, importfn), releasefn, source,
1095 	    qcache_max, flags | VM_XIMPORT, ipl);
1096 }
1097 
1098 void
1099 vmem_destroy(vmem_t *vm)
1100 {
1101 
1102 #if defined(_KERNEL)
1103 	mutex_enter(&vmem_list_lock);
1104 	LIST_REMOVE(vm, vm_alllist);
1105 	mutex_exit(&vmem_list_lock);
1106 #endif /* defined(_KERNEL) */
1107 
1108 	vmem_destroy1(vm);
1109 }
1110 
1111 vmem_size_t
1112 vmem_roundup_size(vmem_t *vm, vmem_size_t size)
1113 {
1114 
1115 	return (size + vm->vm_quantum_mask) & ~vm->vm_quantum_mask;
1116 }
1117 
1118 /*
1119  * vmem_alloc: allocate resource from the arena.
1120  */
1121 
1122 int
1123 vmem_alloc(vmem_t *vm, vmem_size_t size, vm_flag_t flags, vmem_addr_t *addrp)
1124 {
1125 	const vm_flag_t strat __diagused = flags & VM_FITMASK;
1126 	int error;
1127 
1128 	KASSERT((flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
1129 	KASSERT((~flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
1130 
1131 	KASSERT(size > 0);
1132 	KASSERT(strat == VM_BESTFIT || strat == VM_INSTANTFIT);
1133 	if ((flags & VM_SLEEP) != 0) {
1134 		ASSERT_SLEEPABLE();
1135 	}
1136 
1137 #if defined(QCACHE)
1138 	if (size <= vm->vm_qcache_max) {
1139 		void *p;
1140 		int qidx = (size + vm->vm_quantum_mask) >> vm->vm_quantum_shift;
1141 		qcache_t *qc = vm->vm_qcache[qidx - 1];
1142 
1143 		p = pool_cache_get(qc->qc_cache, vmf_to_prf(flags));
1144 		if (addrp != NULL)
1145 			*addrp = (vmem_addr_t)p;
1146 		error = (p == NULL) ? SET_ERROR(ENOMEM) : 0;
1147 		goto out;
1148 	}
1149 #endif /* defined(QCACHE) */
1150 
1151 	error = vmem_xalloc(vm, size, 0, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX,
1152 	    flags, addrp);
1153 #if defined(QCACHE)
1154  out:
1155 #endif /* defined(QCACHE) */
1156 	KASSERTMSG(error || addrp == NULL ||
1157 	    (*addrp & vm->vm_quantum_mask) == 0,
1158 	    "vmem %s mask=0x%jx addr=0x%jx",
1159 	    vm->vm_name, (uintmax_t)vm->vm_quantum_mask, (uintmax_t)*addrp);
1160 	KASSERT(error == 0 || (flags & VM_SLEEP) == 0);
1161 	return error;
1162 }
1163 
1164 int
1165 vmem_xalloc_addr(vmem_t *vm, const vmem_addr_t addr, const vmem_size_t size,
1166     vm_flag_t flags)
1167 {
1168 	vmem_addr_t result;
1169 	int error;
1170 
1171 	KASSERT((addr & vm->vm_quantum_mask) == 0);
1172 	KASSERT(size != 0);
1173 
1174 	flags = (flags & ~VM_INSTANTFIT) | VM_BESTFIT;
1175 
1176 	error = vmem_xalloc(vm, size, 0, 0, 0, addr, addr + size - 1,
1177 	    flags, &result);
1178 
1179 	KASSERT(error || result == addr);
1180 	KASSERT(error == 0 || (flags & VM_SLEEP) == 0);
1181 	return error;
1182 }
1183 
1184 int
1185 vmem_xalloc(vmem_t *vm, const vmem_size_t size0, vmem_size_t align,
1186     const vmem_size_t phase, const vmem_size_t nocross,
1187     const vmem_addr_t minaddr, const vmem_addr_t maxaddr, const vm_flag_t flags,
1188     vmem_addr_t *addrp)
1189 {
1190 	struct vmem_freelist *list;
1191 	struct vmem_freelist *first;
1192 	struct vmem_freelist *end;
1193 	bt_t *bt;
1194 	bt_t *btnew;
1195 	bt_t *btnew2;
1196 	const vmem_size_t size = vmem_roundup_size(vm, size0);
1197 	vm_flag_t strat = flags & VM_FITMASK;
1198 	vmem_addr_t start;
1199 	int rc;
1200 
1201 	KASSERT(size0 > 0);
1202 	KASSERT(size > 0);
1203 	KASSERT(strat == VM_BESTFIT || strat == VM_INSTANTFIT);
1204 	if ((flags & VM_SLEEP) != 0) {
1205 		ASSERT_SLEEPABLE();
1206 	}
1207 	KASSERT((align & vm->vm_quantum_mask) == 0);
1208 	KASSERT((align & (align - 1)) == 0);
1209 	KASSERT((phase & vm->vm_quantum_mask) == 0);
1210 	KASSERT((nocross & vm->vm_quantum_mask) == 0);
1211 	KASSERT((nocross & (nocross - 1)) == 0);
1212 	KASSERT(align == 0 || phase < align);
1213 	KASSERT(phase == 0 || phase < align);
1214 	KASSERT(nocross == 0 || nocross >= size);
1215 	KASSERT(minaddr <= maxaddr);
1216 	KASSERT(!VMEM_CROSS_P(phase, phase + size - 1, nocross));
1217 
1218 	if (align == 0) {
1219 		align = vm->vm_quantum_mask + 1;
1220 	}
1221 
1222 	/*
1223 	 * allocate boundary tags before acquiring the vmem lock.
1224 	 */
1225 	VMEM_LOCK(vm);
1226 	btnew = bt_alloc(vm, flags);
1227 	if (btnew == NULL) {
1228 		VMEM_UNLOCK(vm);
1229 		return SET_ERROR(ENOMEM);
1230 	}
1231 	btnew2 = bt_alloc(vm, flags); /* XXX not necessary if no restrictions */
1232 	if (btnew2 == NULL) {
1233 		bt_free(vm, btnew);
1234 		VMEM_UNLOCK(vm);
1235 		return SET_ERROR(ENOMEM);
1236 	}
1237 
1238 	/*
1239 	 * choose a free block from which we allocate.
1240 	 */
1241 retry_strat:
1242 	first = bt_freehead_toalloc(vm, size, strat);
1243 	end = &vm->vm_freelist[VMEM_MAXORDER];
1244 retry:
1245 	bt = NULL;
1246 	vmem_check(vm);
1247 	if (strat == VM_INSTANTFIT) {
1248 		/*
1249 		 * just choose the first block which satisfies our restrictions.
1250 		 *
1251 		 * note that we don't need to check the size of the blocks
1252 		 * because any blocks found on these list should be larger than
1253 		 * the given size.
1254 		 */
1255 		for (list = first; list < end; list++) {
1256 			bt = LIST_FIRST(list);
1257 			if (bt != NULL) {
1258 				rc = vmem_fit(bt, size, align, phase,
1259 				    nocross, minaddr, maxaddr, &start);
1260 				if (rc == 0) {
1261 					goto gotit;
1262 				}
1263 				/*
1264 				 * don't bother to follow the bt_freelist link
1265 				 * here.  the list can be very long and we are
1266 				 * told to run fast.  blocks from the later free
1267 				 * lists are larger and have better chances to
1268 				 * satisfy our restrictions.
1269 				 */
1270 			}
1271 		}
1272 	} else { /* VM_BESTFIT */
1273 		/*
1274 		 * we assume that, for space efficiency, it's better to
1275 		 * allocate from a smaller block.  thus we will start searching
1276 		 * from the lower-order list than VM_INSTANTFIT.
1277 		 * however, don't bother to find the smallest block in a free
1278 		 * list because the list can be very long.  we can revisit it
1279 		 * if/when it turns out to be a problem.
1280 		 *
1281 		 * note that the 'first' list can contain blocks smaller than
1282 		 * the requested size.  thus we need to check bt_size.
1283 		 */
1284 		for (list = first; list < end; list++) {
1285 			LIST_FOREACH(bt, list, bt_freelist) {
1286 				if (bt->bt_size >= size) {
1287 					rc = vmem_fit(bt, size, align, phase,
1288 					    nocross, minaddr, maxaddr, &start);
1289 					if (rc == 0) {
1290 						goto gotit;
1291 					}
1292 				}
1293 			}
1294 		}
1295 	}
1296 #if 1
1297 	if (strat == VM_INSTANTFIT) {
1298 		strat = VM_BESTFIT;
1299 		goto retry_strat;
1300 	}
1301 #endif
1302 	if (align != vm->vm_quantum_mask + 1 || phase != 0 || nocross != 0) {
1303 
1304 		/*
1305 		 * XXX should try to import a region large enough to
1306 		 * satisfy restrictions?
1307 		 */
1308 
1309 		goto fail;
1310 	}
1311 	/* XXX eeek, minaddr & maxaddr not respected */
1312 	if (vmem_import(vm, size, flags) == 0) {
1313 		goto retry;
1314 	}
1315 	/* XXX */
1316 
1317 	if ((flags & VM_SLEEP) != 0) {
1318 		vmem_kick_pdaemon();
1319 		VMEM_CONDVAR_WAIT(vm);
1320 		goto retry;
1321 	}
1322 fail:
1323 	bt_free(vm, btnew);
1324 	bt_free(vm, btnew2);
1325 	VMEM_UNLOCK(vm);
1326 	return SET_ERROR(ENOMEM);
1327 
1328 gotit:
1329 	KASSERT(bt->bt_type == BT_TYPE_FREE);
1330 	KASSERT(bt->bt_size >= size);
1331 	bt_remfree(vm, bt);
1332 	vmem_check(vm);
1333 	if (bt->bt_start != start) {
1334 		btnew2->bt_type = BT_TYPE_FREE;
1335 		btnew2->bt_start = bt->bt_start;
1336 		btnew2->bt_size = start - bt->bt_start;
1337 		bt->bt_start = start;
1338 		bt->bt_size -= btnew2->bt_size;
1339 		bt_insfree(vm, btnew2);
1340 		bt_insseg(vm, btnew2, TAILQ_PREV(bt, vmem_seglist, bt_seglist));
1341 		btnew2 = NULL;
1342 		vmem_check(vm);
1343 	}
1344 	KASSERT(bt->bt_start == start);
1345 	if (bt->bt_size != size && bt->bt_size - size > vm->vm_quantum_mask) {
1346 		/* split */
1347 		btnew->bt_type = BT_TYPE_BUSY;
1348 		btnew->bt_start = bt->bt_start;
1349 		btnew->bt_size = size;
1350 		bt->bt_start = bt->bt_start + size;
1351 		bt->bt_size -= size;
1352 		bt_insfree(vm, bt);
1353 		bt_insseg(vm, btnew, TAILQ_PREV(bt, vmem_seglist, bt_seglist));
1354 		bt_insbusy(vm, btnew);
1355 		vmem_check(vm);
1356 	} else {
1357 		bt->bt_type = BT_TYPE_BUSY;
1358 		bt_insbusy(vm, bt);
1359 		vmem_check(vm);
1360 		bt_free(vm, btnew);
1361 		btnew = bt;
1362 	}
1363 	if (btnew2 != NULL) {
1364 		bt_free(vm, btnew2);
1365 	}
1366 	KASSERT(btnew->bt_size >= size);
1367 	btnew->bt_type = BT_TYPE_BUSY;
1368 	if (addrp != NULL)
1369 		*addrp = btnew->bt_start;
1370 	VMEM_UNLOCK(vm);
1371 	KASSERTMSG(addrp == NULL ||
1372 	    (*addrp & vm->vm_quantum_mask) == 0,
1373 	    "vmem %s mask=0x%jx addr=0x%jx",
1374 	    vm->vm_name, (uintmax_t)vm->vm_quantum_mask, (uintmax_t)*addrp);
1375 	return 0;
1376 }
1377 
1378 /*
1379  * vmem_free: free the resource to the arena.
1380  */
1381 
1382 void
1383 vmem_free(vmem_t *vm, vmem_addr_t addr, vmem_size_t size)
1384 {
1385 
1386 	KASSERT(size > 0);
1387 	KASSERTMSG((addr & vm->vm_quantum_mask) == 0,
1388 	    "vmem %s mask=0x%jx addr=0x%jx",
1389 	    vm->vm_name, (uintmax_t)vm->vm_quantum_mask, (uintmax_t)addr);
1390 
1391 #if defined(QCACHE)
1392 	if (size <= vm->vm_qcache_max) {
1393 		int qidx = (size + vm->vm_quantum_mask) >> vm->vm_quantum_shift;
1394 		qcache_t *qc = vm->vm_qcache[qidx - 1];
1395 
1396 		pool_cache_put(qc->qc_cache, (void *)addr);
1397 		return;
1398 	}
1399 #endif /* defined(QCACHE) */
1400 
1401 	vmem_xfree(vm, addr, size);
1402 }
1403 
1404 void
1405 vmem_xfree(vmem_t *vm, vmem_addr_t addr, vmem_size_t size)
1406 {
1407 	bt_t *bt;
1408 
1409 	KASSERT(size > 0);
1410 	KASSERTMSG((addr & vm->vm_quantum_mask) == 0,
1411 	    "vmem %s mask=0x%jx addr=0x%jx",
1412 	    vm->vm_name, (uintmax_t)vm->vm_quantum_mask, (uintmax_t)addr);
1413 
1414 	VMEM_LOCK(vm);
1415 
1416 	bt = bt_lookupbusy(vm, addr);
1417 	KASSERTMSG(bt != NULL, "vmem %s addr 0x%jx size 0x%jx",
1418 	    vm->vm_name, (uintmax_t)addr, (uintmax_t)size);
1419 	KASSERT(bt->bt_start == addr);
1420 	KASSERT(bt->bt_size == vmem_roundup_size(vm, size) ||
1421 	    bt->bt_size - vmem_roundup_size(vm, size) <= vm->vm_quantum_mask);
1422 
1423 	/* vmem_xfree_bt() drops the lock. */
1424 	vmem_xfree_bt(vm, bt);
1425 }
1426 
1427 void
1428 vmem_xfreeall(vmem_t *vm)
1429 {
1430 	bt_t *bt;
1431 
1432 #if defined(QCACHE)
1433 	/* This can't be used if the arena has a quantum cache. */
1434 	KASSERT(vm->vm_qcache_max == 0);
1435 #endif /* defined(QCACHE) */
1436 
1437 	for (;;) {
1438 		VMEM_LOCK(vm);
1439 		TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1440 			if (bt->bt_type == BT_TYPE_BUSY)
1441 				break;
1442 		}
1443 		if (bt != NULL) {
1444 			/* vmem_xfree_bt() drops the lock. */
1445 			vmem_xfree_bt(vm, bt);
1446 		} else {
1447 			VMEM_UNLOCK(vm);
1448 			return;
1449 		}
1450 	}
1451 }
1452 
1453 static void
1454 vmem_xfree_bt(vmem_t *vm, bt_t *bt)
1455 {
1456 	bt_t *t;
1457 
1458 	VMEM_ASSERT_LOCKED(vm);
1459 
1460 	KASSERT(bt->bt_type == BT_TYPE_BUSY);
1461 	bt_rembusy(vm, bt);
1462 	bt->bt_type = BT_TYPE_FREE;
1463 
1464 	/* coalesce */
1465 	t = TAILQ_NEXT(bt, bt_seglist);
1466 	if (t != NULL && t->bt_type == BT_TYPE_FREE) {
1467 		KASSERT(BT_END(bt) < t->bt_start);	/* YYY */
1468 		bt_remfree(vm, t);
1469 		bt_remseg(vm, t);
1470 		bt->bt_size += t->bt_size;
1471 		bt_free(vm, t);
1472 	}
1473 	t = TAILQ_PREV(bt, vmem_seglist, bt_seglist);
1474 	if (t != NULL && t->bt_type == BT_TYPE_FREE) {
1475 		KASSERT(BT_END(t) < bt->bt_start);	/* YYY */
1476 		bt_remfree(vm, t);
1477 		bt_remseg(vm, t);
1478 		bt->bt_size += t->bt_size;
1479 		bt->bt_start = t->bt_start;
1480 		bt_free(vm, t);
1481 	}
1482 
1483 	t = TAILQ_PREV(bt, vmem_seglist, bt_seglist);
1484 	KASSERT(t != NULL);
1485 	KASSERT(BT_ISSPAN_P(t) || t->bt_type == BT_TYPE_BUSY);
1486 	if (vm->vm_releasefn != NULL && t->bt_type == BT_TYPE_SPAN &&
1487 	    t->bt_size == bt->bt_size) {
1488 		vmem_addr_t spanaddr;
1489 		vmem_size_t spansize;
1490 
1491 		KASSERT(t->bt_start == bt->bt_start);
1492 		spanaddr = bt->bt_start;
1493 		spansize = bt->bt_size;
1494 		bt_remseg(vm, bt);
1495 		bt_free(vm, bt);
1496 		bt_remseg(vm, t);
1497 		bt_free(vm, t);
1498 		vm->vm_size -= spansize;
1499 		VMEM_CONDVAR_BROADCAST(vm);
1500 		/* bt_freetrim() drops the lock. */
1501 		bt_freetrim(vm, BT_MAXFREE);
1502 		(*vm->vm_releasefn)(vm->vm_arg, spanaddr, spansize);
1503 	} else {
1504 		bt_insfree(vm, bt);
1505 		VMEM_CONDVAR_BROADCAST(vm);
1506 		/* bt_freetrim() drops the lock. */
1507 		bt_freetrim(vm, BT_MAXFREE);
1508 	}
1509 }
1510 
1511 /*
1512  * vmem_add:
1513  *
1514  * => caller must ensure appropriate spl,
1515  *    if the arena can be accessed from interrupt context.
1516  */
1517 
1518 int
1519 vmem_add(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, vm_flag_t flags)
1520 {
1521 	int rv;
1522 
1523 	VMEM_LOCK(vm);
1524 	rv = vmem_add1(vm, addr, size, flags, BT_TYPE_SPAN_STATIC);
1525 	VMEM_UNLOCK(vm);
1526 
1527 	return rv;
1528 }
1529 
1530 /*
1531  * vmem_size: information about arenas size
1532  *
1533  * => return free/allocated size in arena
1534  */
1535 vmem_size_t
1536 vmem_size(vmem_t *vm, int typemask)
1537 {
1538 
1539 	switch (typemask) {
1540 	case VMEM_ALLOC:
1541 		return vm->vm_inuse;
1542 	case VMEM_FREE:
1543 		return vm->vm_size - vm->vm_inuse;
1544 	case VMEM_FREE|VMEM_ALLOC:
1545 		return vm->vm_size;
1546 	default:
1547 		panic("vmem_size");
1548 	}
1549 }
1550 
1551 /* ---- rehash */
1552 
1553 #if defined(_KERNEL)
1554 static struct callout vmem_rehash_ch;
1555 static int vmem_rehash_interval;
1556 static struct workqueue *vmem_rehash_wq;
1557 static struct work vmem_rehash_wk;
1558 
1559 static void
1560 vmem_rehash_all(struct work *wk, void *dummy)
1561 {
1562 	vmem_t *vm;
1563 
1564 	KASSERT(wk == &vmem_rehash_wk);
1565 	mutex_enter(&vmem_list_lock);
1566 	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1567 		size_t desired;
1568 		size_t current;
1569 
1570 		desired = atomic_load_relaxed(&vm->vm_maxbusytag);
1571 		current = atomic_load_relaxed(&vm->vm_hashsize);
1572 
1573 		if (desired > VMEM_HASHSIZE_MAX) {
1574 			desired = VMEM_HASHSIZE_MAX;
1575 		} else if (desired < VMEM_HASHSIZE_MIN) {
1576 			desired = VMEM_HASHSIZE_MIN;
1577 		}
1578 		if (desired > current * 2 || desired * 2 < current) {
1579 			vmem_rehash(vm, desired, VM_NOSLEEP);
1580 		}
1581 	}
1582 	mutex_exit(&vmem_list_lock);
1583 
1584 	callout_schedule(&vmem_rehash_ch, vmem_rehash_interval);
1585 }
1586 
1587 static void
1588 vmem_rehash_all_kick(void *dummy)
1589 {
1590 
1591 	workqueue_enqueue(vmem_rehash_wq, &vmem_rehash_wk, NULL);
1592 }
1593 
1594 void
1595 vmem_rehash_start(void)
1596 {
1597 	int error;
1598 
1599 	error = workqueue_create(&vmem_rehash_wq, "vmem_rehash",
1600 	    vmem_rehash_all, NULL, PRI_VM, IPL_SOFTCLOCK, WQ_MPSAFE);
1601 	if (error) {
1602 		panic("%s: workqueue_create %d\n", __func__, error);
1603 	}
1604 	callout_init(&vmem_rehash_ch, CALLOUT_MPSAFE);
1605 	callout_setfunc(&vmem_rehash_ch, vmem_rehash_all_kick, NULL);
1606 
1607 	vmem_rehash_interval = hz * 10;
1608 	callout_schedule(&vmem_rehash_ch, vmem_rehash_interval);
1609 }
1610 #endif /* defined(_KERNEL) */
1611 
1612 /* ---- debug */
1613 
1614 #if defined(DDB) || defined(UNITTEST) || defined(VMEM_SANITY)
1615 
1616 static void bt_dump(const bt_t *, void (*)(const char *, ...)
1617     __printflike(1, 2));
1618 
1619 static const char *
1620 bt_type_string(int type)
1621 {
1622 	static const char * const table[] = {
1623 		[BT_TYPE_BUSY] = "busy",
1624 		[BT_TYPE_FREE] = "free",
1625 		[BT_TYPE_SPAN] = "span",
1626 		[BT_TYPE_SPAN_STATIC] = "static span",
1627 	};
1628 
1629 	if (type >= __arraycount(table)) {
1630 		return "BOGUS";
1631 	}
1632 	return table[type];
1633 }
1634 
1635 static void
1636 bt_dump(const bt_t *bt, void (*pr)(const char *, ...))
1637 {
1638 
1639 	(*pr)("\t%p: %" PRIu64 ", %" PRIu64 ", %d(%s)\n",
1640 	    bt, (uint64_t)bt->bt_start, (uint64_t)bt->bt_size,
1641 	    bt->bt_type, bt_type_string(bt->bt_type));
1642 }
1643 
1644 static void
1645 vmem_dump(const vmem_t *vm , void (*pr)(const char *, ...) __printflike(1, 2))
1646 {
1647 	const bt_t *bt;
1648 	int i;
1649 
1650 	(*pr)("vmem %p '%s'\n", vm, vm->vm_name);
1651 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1652 		bt_dump(bt, pr);
1653 	}
1654 
1655 	for (i = 0; i < VMEM_MAXORDER; i++) {
1656 		const struct vmem_freelist *fl = &vm->vm_freelist[i];
1657 
1658 		if (LIST_EMPTY(fl)) {
1659 			continue;
1660 		}
1661 
1662 		(*pr)("freelist[%d]\n", i);
1663 		LIST_FOREACH(bt, fl, bt_freelist) {
1664 			bt_dump(bt, pr);
1665 		}
1666 	}
1667 }
1668 
1669 #endif /* defined(DDB) || defined(UNITTEST) || defined(VMEM_SANITY) */
1670 
1671 #if defined(DDB)
1672 static bt_t *
1673 vmem_whatis_lookup(vmem_t *vm, uintptr_t addr)
1674 {
1675 	bt_t *bt;
1676 
1677 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1678 		if (BT_ISSPAN_P(bt)) {
1679 			continue;
1680 		}
1681 		if (bt->bt_start <= addr && addr <= BT_END(bt)) {
1682 			return bt;
1683 		}
1684 	}
1685 
1686 	return NULL;
1687 }
1688 
1689 void
1690 vmem_whatis(uintptr_t addr, void (*pr)(const char *, ...))
1691 {
1692 	vmem_t *vm;
1693 
1694 	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1695 		bt_t *bt;
1696 
1697 		bt = vmem_whatis_lookup(vm, addr);
1698 		if (bt == NULL) {
1699 			continue;
1700 		}
1701 		(*pr)("%p is %p+%zu in VMEM '%s' (%s)\n",
1702 		    (void *)addr, (void *)bt->bt_start,
1703 		    (size_t)(addr - bt->bt_start), vm->vm_name,
1704 		    (bt->bt_type == BT_TYPE_BUSY) ? "allocated" : "free");
1705 	}
1706 }
1707 
1708 void
1709 vmem_printall(const char *modif, void (*pr)(const char *, ...))
1710 {
1711 	const vmem_t *vm;
1712 
1713 	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1714 		vmem_dump(vm, pr);
1715 	}
1716 }
1717 
1718 void
1719 vmem_print(uintptr_t addr, const char *modif, void (*pr)(const char *, ...))
1720 {
1721 	const vmem_t *vm = (const void *)addr;
1722 
1723 	vmem_dump(vm, pr);
1724 }
1725 #endif /* defined(DDB) */
1726 
1727 #if defined(_KERNEL)
1728 #define vmem_printf printf
1729 #else
1730 #include <stdio.h>
1731 #include <stdarg.h>
1732 
1733 static void
1734 vmem_printf(const char *fmt, ...)
1735 {
1736 	va_list ap;
1737 	va_start(ap, fmt);
1738 	vprintf(fmt, ap);
1739 	va_end(ap);
1740 }
1741 #endif
1742 
1743 #if defined(VMEM_SANITY)
1744 
1745 static bool
1746 vmem_check_sanity(vmem_t *vm)
1747 {
1748 	const bt_t *bt, *bt2;
1749 
1750 	KASSERT(vm != NULL);
1751 
1752 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1753 		if (bt->bt_start > BT_END(bt)) {
1754 			printf("corrupted tag\n");
1755 			bt_dump(bt, vmem_printf);
1756 			return false;
1757 		}
1758 	}
1759 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1760 		TAILQ_FOREACH(bt2, &vm->vm_seglist, bt_seglist) {
1761 			if (bt == bt2) {
1762 				continue;
1763 			}
1764 			if (BT_ISSPAN_P(bt) != BT_ISSPAN_P(bt2)) {
1765 				continue;
1766 			}
1767 			if (bt->bt_start <= BT_END(bt2) &&
1768 			    bt2->bt_start <= BT_END(bt)) {
1769 				printf("overwrapped tags\n");
1770 				bt_dump(bt, vmem_printf);
1771 				bt_dump(bt2, vmem_printf);
1772 				return false;
1773 			}
1774 		}
1775 	}
1776 
1777 	return true;
1778 }
1779 
1780 static void
1781 vmem_check(vmem_t *vm)
1782 {
1783 
1784 	if (!vmem_check_sanity(vm)) {
1785 		panic("insanity vmem %p", vm);
1786 	}
1787 }
1788 
1789 #endif /* defined(VMEM_SANITY) */
1790 
1791 #if defined(UNITTEST)
1792 int
1793 main(void)
1794 {
1795 	int rc;
1796 	vmem_t *vm;
1797 	vmem_addr_t p;
1798 	struct reg {
1799 		vmem_addr_t p;
1800 		vmem_size_t sz;
1801 		bool x;
1802 	} *reg = NULL;
1803 	int nreg = 0;
1804 	int nalloc = 0;
1805 	int nfree = 0;
1806 	vmem_size_t total = 0;
1807 #if 1
1808 	vm_flag_t strat = VM_INSTANTFIT;
1809 #else
1810 	vm_flag_t strat = VM_BESTFIT;
1811 #endif
1812 
1813 	vm = vmem_create("test", 0, 0, 1, NULL, NULL, NULL, 0, VM_SLEEP,
1814 #ifdef _KERNEL
1815 	    IPL_NONE
1816 #else
1817 	    0
1818 #endif
1819 	    );
1820 	if (vm == NULL) {
1821 		printf("vmem_create\n");
1822 		exit(EXIT_FAILURE);
1823 	}
1824 	vmem_dump(vm, vmem_printf);
1825 
1826 	rc = vmem_add(vm, 0, 50, VM_SLEEP);
1827 	assert(rc == 0);
1828 	rc = vmem_add(vm, 100, 200, VM_SLEEP);
1829 	assert(rc == 0);
1830 	rc = vmem_add(vm, 2000, 1, VM_SLEEP);
1831 	assert(rc == 0);
1832 	rc = vmem_add(vm, 40000, 65536, VM_SLEEP);
1833 	assert(rc == 0);
1834 	rc = vmem_add(vm, 10000, 10000, VM_SLEEP);
1835 	assert(rc == 0);
1836 	rc = vmem_add(vm, 500, 1000, VM_SLEEP);
1837 	assert(rc == 0);
1838 	rc = vmem_add(vm, 0xffffff00, 0x100, VM_SLEEP);
1839 	assert(rc == 0);
1840 	rc = vmem_xalloc(vm, 0x101, 0, 0, 0,
1841 	    0xffffff00, 0xffffffff, strat|VM_SLEEP, &p);
1842 	assert(rc != 0);
1843 	rc = vmem_xalloc(vm, 50, 0, 0, 0, 0, 49, strat|VM_SLEEP, &p);
1844 	assert(rc == 0 && p == 0);
1845 	vmem_xfree(vm, p, 50);
1846 	rc = vmem_xalloc(vm, 25, 0, 0, 0, 0, 24, strat|VM_SLEEP, &p);
1847 	assert(rc == 0 && p == 0);
1848 	rc = vmem_xalloc(vm, 0x100, 0, 0, 0,
1849 	    0xffffff01, 0xffffffff, strat|VM_SLEEP, &p);
1850 	assert(rc != 0);
1851 	rc = vmem_xalloc(vm, 0x100, 0, 0, 0,
1852 	    0xffffff00, 0xfffffffe, strat|VM_SLEEP, &p);
1853 	assert(rc != 0);
1854 	rc = vmem_xalloc(vm, 0x100, 0, 0, 0,
1855 	    0xffffff00, 0xffffffff, strat|VM_SLEEP, &p);
1856 	assert(rc == 0);
1857 	vmem_dump(vm, vmem_printf);
1858 	for (;;) {
1859 		struct reg *r;
1860 		int t = rand() % 100;
1861 
1862 		if (t > 45) {
1863 			/* alloc */
1864 			vmem_size_t sz = rand() % 500 + 1;
1865 			bool x;
1866 			vmem_size_t align, phase, nocross;
1867 			vmem_addr_t minaddr, maxaddr;
1868 
1869 			if (t > 70) {
1870 				x = true;
1871 				/* XXX */
1872 				align = 1 << (rand() % 15);
1873 				phase = rand() % 65536;
1874 				nocross = 1 << (rand() % 15);
1875 				if (align <= phase) {
1876 					phase = 0;
1877 				}
1878 				if (VMEM_CROSS_P(phase, phase + sz - 1,
1879 				    nocross)) {
1880 					nocross = 0;
1881 				}
1882 				do {
1883 					minaddr = rand() % 50000;
1884 					maxaddr = rand() % 70000;
1885 				} while (minaddr > maxaddr);
1886 				printf("=== xalloc %" PRIu64
1887 				    " align=%" PRIu64 ", phase=%" PRIu64
1888 				    ", nocross=%" PRIu64 ", min=%" PRIu64
1889 				    ", max=%" PRIu64 "\n",
1890 				    (uint64_t)sz,
1891 				    (uint64_t)align,
1892 				    (uint64_t)phase,
1893 				    (uint64_t)nocross,
1894 				    (uint64_t)minaddr,
1895 				    (uint64_t)maxaddr);
1896 				rc = vmem_xalloc(vm, sz, align, phase, nocross,
1897 				    minaddr, maxaddr, strat|VM_SLEEP, &p);
1898 			} else {
1899 				x = false;
1900 				printf("=== alloc %" PRIu64 "\n", (uint64_t)sz);
1901 				rc = vmem_alloc(vm, sz, strat|VM_SLEEP, &p);
1902 			}
1903 			printf("-> %" PRIu64 "\n", (uint64_t)p);
1904 			vmem_dump(vm, vmem_printf);
1905 			if (rc != 0) {
1906 				if (x) {
1907 					continue;
1908 				}
1909 				break;
1910 			}
1911 			nreg++;
1912 			reg = realloc(reg, sizeof(*reg) * nreg);
1913 			r = &reg[nreg - 1];
1914 			r->p = p;
1915 			r->sz = sz;
1916 			r->x = x;
1917 			total += sz;
1918 			nalloc++;
1919 		} else if (nreg != 0) {
1920 			/* free */
1921 			r = &reg[rand() % nreg];
1922 			printf("=== free %" PRIu64 ", %" PRIu64 "\n",
1923 			    (uint64_t)r->p, (uint64_t)r->sz);
1924 			if (r->x) {
1925 				vmem_xfree(vm, r->p, r->sz);
1926 			} else {
1927 				vmem_free(vm, r->p, r->sz);
1928 			}
1929 			total -= r->sz;
1930 			vmem_dump(vm, vmem_printf);
1931 			*r = reg[nreg - 1];
1932 			nreg--;
1933 			nfree++;
1934 		}
1935 		printf("total=%" PRIu64 "\n", (uint64_t)total);
1936 	}
1937 	fprintf(stderr, "total=%" PRIu64 ", nalloc=%d, nfree=%d\n",
1938 	    (uint64_t)total, nalloc, nfree);
1939 	exit(EXIT_SUCCESS);
1940 }
1941 #endif /* defined(UNITTEST) */
1942