xref: /netbsd-src/sys/kern/subr_vmem.c (revision 53b02e147d4ed531c0d2a5ca9b3e8026ba3e99b5)
1 /*	$NetBSD: subr_vmem.c,v 1.106 2021/08/17 22:00:32 andvar 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 interferance 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 1.106 2021/08/17 22:00:32 andvar 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/hash.h>
57 #include <sys/queue.h>
58 #include <sys/bitops.h>
59 
60 #if defined(_KERNEL)
61 #include <sys/systm.h>
62 #include <sys/kernel.h>	/* hz */
63 #include <sys/callout.h>
64 #include <sys/kmem.h>
65 #include <sys/pool.h>
66 #include <sys/vmem.h>
67 #include <sys/vmem_impl.h>
68 #include <sys/workqueue.h>
69 #include <sys/atomic.h>
70 #include <uvm/uvm.h>
71 #include <uvm/uvm_extern.h>
72 #include <uvm/uvm_km.h>
73 #include <uvm/uvm_page.h>
74 #include <uvm/uvm_pdaemon.h>
75 #else /* defined(_KERNEL) */
76 #include <stdio.h>
77 #include <errno.h>
78 #include <assert.h>
79 #include <stdlib.h>
80 #include <string.h>
81 #include "../sys/vmem.h"
82 #include "../sys/vmem_impl.h"
83 #endif /* defined(_KERNEL) */
84 
85 
86 #if defined(_KERNEL)
87 #include <sys/evcnt.h>
88 #define VMEM_EVCNT_DEFINE(name) \
89 struct evcnt vmem_evcnt_##name = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, \
90     "vmem", #name); \
91 EVCNT_ATTACH_STATIC(vmem_evcnt_##name);
92 #define VMEM_EVCNT_INCR(ev)	vmem_evcnt_##ev.ev_count++
93 #define VMEM_EVCNT_DECR(ev)	vmem_evcnt_##ev.ev_count--
94 
95 VMEM_EVCNT_DEFINE(static_bt_count)
96 VMEM_EVCNT_DEFINE(static_bt_inuse)
97 
98 #define	VMEM_CONDVAR_INIT(vm, wchan)	cv_init(&vm->vm_cv, wchan)
99 #define	VMEM_CONDVAR_DESTROY(vm)	cv_destroy(&vm->vm_cv)
100 #define	VMEM_CONDVAR_WAIT(vm)		cv_wait(&vm->vm_cv, &vm->vm_lock)
101 #define	VMEM_CONDVAR_BROADCAST(vm)	cv_broadcast(&vm->vm_cv)
102 
103 #else /* defined(_KERNEL) */
104 
105 #define VMEM_EVCNT_INCR(ev)	/* nothing */
106 #define VMEM_EVCNT_DECR(ev)	/* nothing */
107 
108 #define	VMEM_CONDVAR_INIT(vm, wchan)	/* nothing */
109 #define	VMEM_CONDVAR_DESTROY(vm)	/* nothing */
110 #define	VMEM_CONDVAR_WAIT(vm)		/* nothing */
111 #define	VMEM_CONDVAR_BROADCAST(vm)	/* nothing */
112 
113 #define	UNITTEST
114 #define	KASSERT(a)		assert(a)
115 #define	mutex_init(a, b, c)	/* nothing */
116 #define	mutex_destroy(a)	/* nothing */
117 #define	mutex_enter(a)		/* nothing */
118 #define	mutex_tryenter(a)	true
119 #define	mutex_exit(a)		/* nothing */
120 #define	mutex_owned(a)		/* nothing */
121 #define	ASSERT_SLEEPABLE()	/* nothing */
122 #define	panic(...)		printf(__VA_ARGS__); abort()
123 #endif /* defined(_KERNEL) */
124 
125 #if defined(VMEM_SANITY)
126 static void vmem_check(vmem_t *);
127 #else /* defined(VMEM_SANITY) */
128 #define vmem_check(vm)	/* nothing */
129 #endif /* defined(VMEM_SANITY) */
130 
131 #define	VMEM_HASHSIZE_MIN	1	/* XXX */
132 #define	VMEM_HASHSIZE_MAX	65536	/* XXX */
133 #define	VMEM_HASHSIZE_INIT	1
134 
135 #define	VM_FITMASK	(VM_BESTFIT | VM_INSTANTFIT)
136 
137 #if defined(_KERNEL)
138 static bool vmem_bootstrapped = false;
139 static kmutex_t vmem_list_lock;
140 static LIST_HEAD(, vmem) vmem_list = LIST_HEAD_INITIALIZER(vmem_list);
141 #endif /* defined(_KERNEL) */
142 
143 /* ---- misc */
144 
145 #define	VMEM_LOCK(vm)		mutex_enter(&vm->vm_lock)
146 #define	VMEM_TRYLOCK(vm)	mutex_tryenter(&vm->vm_lock)
147 #define	VMEM_UNLOCK(vm)		mutex_exit(&vm->vm_lock)
148 #define	VMEM_LOCK_INIT(vm, ipl)	mutex_init(&vm->vm_lock, MUTEX_DEFAULT, ipl)
149 #define	VMEM_LOCK_DESTROY(vm)	mutex_destroy(&vm->vm_lock)
150 #define	VMEM_ASSERT_LOCKED(vm)	KASSERT(mutex_owned(&vm->vm_lock))
151 
152 #define	VMEM_ALIGNUP(addr, align) \
153 	(-(-(addr) & -(align)))
154 
155 #define	VMEM_CROSS_P(addr1, addr2, boundary) \
156 	((((addr1) ^ (addr2)) & -(boundary)) != 0)
157 
158 #define	ORDER2SIZE(order)	((vmem_size_t)1 << (order))
159 #define	SIZE2ORDER(size)	((int)ilog2(size))
160 
161 #if !defined(_KERNEL)
162 #define	xmalloc(sz, flags)	malloc(sz)
163 #define	xfree(p, sz)		free(p)
164 #define	bt_alloc(vm, flags)	malloc(sizeof(bt_t))
165 #define	bt_free(vm, bt)		free(bt)
166 #else /* defined(_KERNEL) */
167 
168 #define	xmalloc(sz, flags) \
169     kmem_alloc(sz, ((flags) & VM_SLEEP) ? KM_SLEEP : KM_NOSLEEP);
170 #define	xfree(p, sz)		kmem_free(p, sz);
171 
172 /*
173  * BT_RESERVE calculation:
174  * we allocate memory for boundary tags with vmem; therefore we have
175  * to keep a reserve of bts used to allocated memory for bts.
176  * This reserve is 4 for each arena involved in allocating vmems memory.
177  * BT_MAXFREE: don't cache excessive counts of bts in arenas
178  */
179 #define STATIC_BT_COUNT 200
180 #define BT_MINRESERVE 4
181 #define BT_MAXFREE 64
182 
183 static struct vmem_btag static_bts[STATIC_BT_COUNT];
184 static int static_bt_count = STATIC_BT_COUNT;
185 
186 static struct vmem kmem_va_meta_arena_store;
187 vmem_t *kmem_va_meta_arena;
188 static struct vmem kmem_meta_arena_store;
189 vmem_t *kmem_meta_arena = NULL;
190 
191 static kmutex_t vmem_btag_refill_lock;
192 static kmutex_t vmem_btag_lock;
193 static LIST_HEAD(, vmem_btag) vmem_btag_freelist;
194 static size_t vmem_btag_freelist_count = 0;
195 static struct pool vmem_btag_pool;
196 
197 static void vmem_xfree_bt(vmem_t *, bt_t *);
198 
199 static void
200 vmem_kick_pdaemon(void)
201 {
202 #if defined(_KERNEL)
203 	uvm_kick_pdaemon();
204 #endif
205 }
206 
207 /* ---- boundary tag */
208 
209 static int bt_refill(vmem_t *vm);
210 static int bt_refill_locked(vmem_t *vm);
211 
212 static void *
213 pool_page_alloc_vmem_meta(struct pool *pp, int flags)
214 {
215 	const vm_flag_t vflags = (flags & PR_WAITOK) ? VM_SLEEP: VM_NOSLEEP;
216 	vmem_addr_t va;
217 	int ret;
218 
219 	ret = vmem_alloc(kmem_meta_arena, pp->pr_alloc->pa_pagesz,
220 	    (vflags & ~VM_FITMASK) | VM_INSTANTFIT | VM_POPULATING, &va);
221 
222 	return ret ? NULL : (void *)va;
223 }
224 
225 static void
226 pool_page_free_vmem_meta(struct pool *pp, void *v)
227 {
228 
229 	vmem_free(kmem_meta_arena, (vmem_addr_t)v, pp->pr_alloc->pa_pagesz);
230 }
231 
232 /* allocator for vmem-pool metadata */
233 struct pool_allocator pool_allocator_vmem_meta = {
234 	.pa_alloc = pool_page_alloc_vmem_meta,
235 	.pa_free = pool_page_free_vmem_meta,
236 	.pa_pagesz = 0
237 };
238 
239 static int
240 bt_refill_locked(vmem_t *vm)
241 {
242 	bt_t *bt;
243 
244 	VMEM_ASSERT_LOCKED(vm);
245 
246 	if (vm->vm_nfreetags > BT_MINRESERVE) {
247 		return 0;
248 	}
249 
250 	mutex_enter(&vmem_btag_lock);
251 	while (!LIST_EMPTY(&vmem_btag_freelist) &&
252 	    vm->vm_nfreetags <= BT_MINRESERVE) {
253 		bt = LIST_FIRST(&vmem_btag_freelist);
254 		LIST_REMOVE(bt, bt_freelist);
255 		LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
256 		vm->vm_nfreetags++;
257 		vmem_btag_freelist_count--;
258 		VMEM_EVCNT_INCR(static_bt_inuse);
259 	}
260 	mutex_exit(&vmem_btag_lock);
261 
262 	while (vm->vm_nfreetags <= BT_MINRESERVE) {
263 		VMEM_UNLOCK(vm);
264 		mutex_enter(&vmem_btag_refill_lock);
265 		bt = pool_get(&vmem_btag_pool, PR_NOWAIT);
266 		mutex_exit(&vmem_btag_refill_lock);
267 		VMEM_LOCK(vm);
268 		if (bt == NULL)
269 			break;
270 		LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
271 		vm->vm_nfreetags++;
272 	}
273 
274 	if (vm->vm_nfreetags <= BT_MINRESERVE) {
275 		return ENOMEM;
276 	}
277 
278 	if (kmem_meta_arena != NULL) {
279 		VMEM_UNLOCK(vm);
280 		(void)bt_refill(kmem_arena);
281 		(void)bt_refill(kmem_va_meta_arena);
282 		(void)bt_refill(kmem_meta_arena);
283 		VMEM_LOCK(vm);
284 	}
285 
286 	return 0;
287 }
288 
289 static int
290 bt_refill(vmem_t *vm)
291 {
292 	int rv;
293 
294 	VMEM_LOCK(vm);
295 	rv = bt_refill_locked(vm);
296 	VMEM_UNLOCK(vm);
297 	return rv;
298 }
299 
300 static bt_t *
301 bt_alloc(vmem_t *vm, vm_flag_t flags)
302 {
303 	bt_t *bt;
304 
305 	VMEM_ASSERT_LOCKED(vm);
306 
307 	while (vm->vm_nfreetags <= BT_MINRESERVE && (flags & VM_POPULATING) == 0) {
308 		if (bt_refill_locked(vm)) {
309 			if ((flags & VM_NOSLEEP) != 0) {
310 				return NULL;
311 			}
312 
313 			/*
314 			 * It would be nice to wait for something specific here
315 			 * but there are multiple ways that a retry could
316 			 * succeed and we can't wait for multiple things
317 			 * simultaneously.  So we'll just sleep for an arbitrary
318 			 * short period of time and retry regardless.
319 			 * This should be a very rare case.
320 			 */
321 
322 			vmem_kick_pdaemon();
323 			kpause("btalloc", false, 1, &vm->vm_lock);
324 		}
325 	}
326 	bt = LIST_FIRST(&vm->vm_freetags);
327 	LIST_REMOVE(bt, bt_freelist);
328 	vm->vm_nfreetags--;
329 
330 	return bt;
331 }
332 
333 static void
334 bt_free(vmem_t *vm, bt_t *bt)
335 {
336 
337 	VMEM_ASSERT_LOCKED(vm);
338 
339 	LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
340 	vm->vm_nfreetags++;
341 }
342 
343 static void
344 bt_freetrim(vmem_t *vm, int freelimit)
345 {
346 	bt_t *t;
347 	LIST_HEAD(, vmem_btag) tofree;
348 
349 	VMEM_ASSERT_LOCKED(vm);
350 
351 	LIST_INIT(&tofree);
352 
353 	while (vm->vm_nfreetags > freelimit) {
354 		bt_t *bt = LIST_FIRST(&vm->vm_freetags);
355 		LIST_REMOVE(bt, bt_freelist);
356 		vm->vm_nfreetags--;
357 		if (bt >= static_bts
358 		    && bt < &static_bts[STATIC_BT_COUNT]) {
359 			mutex_enter(&vmem_btag_lock);
360 			LIST_INSERT_HEAD(&vmem_btag_freelist, bt, bt_freelist);
361 			vmem_btag_freelist_count++;
362 			mutex_exit(&vmem_btag_lock);
363 			VMEM_EVCNT_DECR(static_bt_inuse);
364 		} else {
365 			LIST_INSERT_HEAD(&tofree, bt, bt_freelist);
366 		}
367 	}
368 
369 	VMEM_UNLOCK(vm);
370 	while (!LIST_EMPTY(&tofree)) {
371 		t = LIST_FIRST(&tofree);
372 		LIST_REMOVE(t, bt_freelist);
373 		pool_put(&vmem_btag_pool, t);
374 	}
375 }
376 #endif	/* defined(_KERNEL) */
377 
378 /*
379  * freelist[0] ... [1, 1]
380  * freelist[1] ... [2, 3]
381  * freelist[2] ... [4, 7]
382  * freelist[3] ... [8, 15]
383  *  :
384  * freelist[n] ... [(1 << n), (1 << (n + 1)) - 1]
385  *  :
386  */
387 
388 static struct vmem_freelist *
389 bt_freehead_tofree(vmem_t *vm, vmem_size_t size)
390 {
391 	const vmem_size_t qsize = size >> vm->vm_quantum_shift;
392 	const int idx = SIZE2ORDER(qsize);
393 
394 	KASSERT(size != 0 && qsize != 0);
395 	KASSERT((size & vm->vm_quantum_mask) == 0);
396 	KASSERT(idx >= 0);
397 	KASSERT(idx < VMEM_MAXORDER);
398 
399 	return &vm->vm_freelist[idx];
400 }
401 
402 /*
403  * bt_freehead_toalloc: return the freelist for the given size and allocation
404  * strategy.
405  *
406  * for VM_INSTANTFIT, return the list in which any blocks are large enough
407  * for the requested size.  otherwise, return the list which can have blocks
408  * large enough for the requested size.
409  */
410 
411 static struct vmem_freelist *
412 bt_freehead_toalloc(vmem_t *vm, vmem_size_t size, vm_flag_t strat)
413 {
414 	const vmem_size_t qsize = size >> vm->vm_quantum_shift;
415 	int idx = SIZE2ORDER(qsize);
416 
417 	KASSERT(size != 0 && qsize != 0);
418 	KASSERT((size & vm->vm_quantum_mask) == 0);
419 
420 	if (strat == VM_INSTANTFIT && ORDER2SIZE(idx) != qsize) {
421 		idx++;
422 		/* check too large request? */
423 	}
424 	KASSERT(idx >= 0);
425 	KASSERT(idx < VMEM_MAXORDER);
426 
427 	return &vm->vm_freelist[idx];
428 }
429 
430 /* ---- boundary tag hash */
431 
432 static struct vmem_hashlist *
433 bt_hashhead(vmem_t *vm, vmem_addr_t addr)
434 {
435 	struct vmem_hashlist *list;
436 	unsigned int hash;
437 
438 	hash = hash32_buf(&addr, sizeof(addr), HASH32_BUF_INIT);
439 	list = &vm->vm_hashlist[hash & vm->vm_hashmask];
440 
441 	return list;
442 }
443 
444 static bt_t *
445 bt_lookupbusy(vmem_t *vm, vmem_addr_t addr)
446 {
447 	struct vmem_hashlist *list;
448 	bt_t *bt;
449 
450 	list = bt_hashhead(vm, addr);
451 	LIST_FOREACH(bt, list, bt_hashlist) {
452 		if (bt->bt_start == addr) {
453 			break;
454 		}
455 	}
456 
457 	return bt;
458 }
459 
460 static void
461 bt_rembusy(vmem_t *vm, bt_t *bt)
462 {
463 
464 	KASSERT(vm->vm_nbusytag > 0);
465 	vm->vm_inuse -= bt->bt_size;
466 	vm->vm_nbusytag--;
467 	LIST_REMOVE(bt, bt_hashlist);
468 }
469 
470 static void
471 bt_insbusy(vmem_t *vm, bt_t *bt)
472 {
473 	struct vmem_hashlist *list;
474 
475 	KASSERT(bt->bt_type == BT_TYPE_BUSY);
476 
477 	list = bt_hashhead(vm, bt->bt_start);
478 	LIST_INSERT_HEAD(list, bt, bt_hashlist);
479 	if (++vm->vm_nbusytag > vm->vm_maxbusytag) {
480 		vm->vm_maxbusytag = vm->vm_nbusytag;
481 	}
482 	vm->vm_inuse += bt->bt_size;
483 }
484 
485 /* ---- boundary tag list */
486 
487 static void
488 bt_remseg(vmem_t *vm, bt_t *bt)
489 {
490 
491 	TAILQ_REMOVE(&vm->vm_seglist, bt, bt_seglist);
492 }
493 
494 static void
495 bt_insseg(vmem_t *vm, bt_t *bt, bt_t *prev)
496 {
497 
498 	TAILQ_INSERT_AFTER(&vm->vm_seglist, prev, bt, bt_seglist);
499 }
500 
501 static void
502 bt_insseg_tail(vmem_t *vm, bt_t *bt)
503 {
504 
505 	TAILQ_INSERT_TAIL(&vm->vm_seglist, bt, bt_seglist);
506 }
507 
508 static void
509 bt_remfree(vmem_t *vm, bt_t *bt)
510 {
511 
512 	KASSERT(bt->bt_type == BT_TYPE_FREE);
513 
514 	LIST_REMOVE(bt, bt_freelist);
515 }
516 
517 static void
518 bt_insfree(vmem_t *vm, bt_t *bt)
519 {
520 	struct vmem_freelist *list;
521 
522 	list = bt_freehead_tofree(vm, bt->bt_size);
523 	LIST_INSERT_HEAD(list, bt, bt_freelist);
524 }
525 
526 /* ---- vmem internal functions */
527 
528 #if defined(QCACHE)
529 static inline vm_flag_t
530 prf_to_vmf(int prflags)
531 {
532 	vm_flag_t vmflags;
533 
534 	KASSERT((prflags & ~(PR_LIMITFAIL | PR_WAITOK | PR_NOWAIT)) == 0);
535 	if ((prflags & PR_WAITOK) != 0) {
536 		vmflags = VM_SLEEP;
537 	} else {
538 		vmflags = VM_NOSLEEP;
539 	}
540 	return vmflags;
541 }
542 
543 static inline int
544 vmf_to_prf(vm_flag_t vmflags)
545 {
546 	int prflags;
547 
548 	if ((vmflags & VM_SLEEP) != 0) {
549 		prflags = PR_WAITOK;
550 	} else {
551 		prflags = PR_NOWAIT;
552 	}
553 	return prflags;
554 }
555 
556 static size_t
557 qc_poolpage_size(size_t qcache_max)
558 {
559 	int i;
560 
561 	for (i = 0; ORDER2SIZE(i) <= qcache_max * 3; i++) {
562 		/* nothing */
563 	}
564 	return ORDER2SIZE(i);
565 }
566 
567 static void *
568 qc_poolpage_alloc(struct pool *pool, int prflags)
569 {
570 	qcache_t *qc = QC_POOL_TO_QCACHE(pool);
571 	vmem_t *vm = qc->qc_vmem;
572 	vmem_addr_t addr;
573 
574 	if (vmem_alloc(vm, pool->pr_alloc->pa_pagesz,
575 	    prf_to_vmf(prflags) | VM_INSTANTFIT, &addr) != 0)
576 		return NULL;
577 	return (void *)addr;
578 }
579 
580 static void
581 qc_poolpage_free(struct pool *pool, void *addr)
582 {
583 	qcache_t *qc = QC_POOL_TO_QCACHE(pool);
584 	vmem_t *vm = qc->qc_vmem;
585 
586 	vmem_free(vm, (vmem_addr_t)addr, pool->pr_alloc->pa_pagesz);
587 }
588 
589 static void
590 qc_init(vmem_t *vm, size_t qcache_max, int ipl)
591 {
592 	qcache_t *prevqc;
593 	struct pool_allocator *pa;
594 	int qcache_idx_max;
595 	int i;
596 
597 	KASSERT((qcache_max & vm->vm_quantum_mask) == 0);
598 	if (qcache_max > (VMEM_QCACHE_IDX_MAX << vm->vm_quantum_shift)) {
599 		qcache_max = VMEM_QCACHE_IDX_MAX << vm->vm_quantum_shift;
600 	}
601 	vm->vm_qcache_max = qcache_max;
602 	pa = &vm->vm_qcache_allocator;
603 	memset(pa, 0, sizeof(*pa));
604 	pa->pa_alloc = qc_poolpage_alloc;
605 	pa->pa_free = qc_poolpage_free;
606 	pa->pa_pagesz = qc_poolpage_size(qcache_max);
607 
608 	qcache_idx_max = qcache_max >> vm->vm_quantum_shift;
609 	prevqc = NULL;
610 	for (i = qcache_idx_max; i > 0; i--) {
611 		qcache_t *qc = &vm->vm_qcache_store[i - 1];
612 		size_t size = i << vm->vm_quantum_shift;
613 		pool_cache_t pc;
614 
615 		qc->qc_vmem = vm;
616 		snprintf(qc->qc_name, sizeof(qc->qc_name), "%s-%zu",
617 		    vm->vm_name, size);
618 
619 		pc = pool_cache_init(size,
620 		    ORDER2SIZE(vm->vm_quantum_shift), 0,
621 		    PR_NOALIGN | PR_NOTOUCH | PR_RECURSIVE /* XXX */,
622 		    qc->qc_name, pa, ipl, NULL, NULL, NULL);
623 
624 		KASSERT(pc);
625 
626 		qc->qc_cache = pc;
627 		KASSERT(qc->qc_cache != NULL);	/* XXX */
628 		if (prevqc != NULL &&
629 		    qc->qc_cache->pc_pool.pr_itemsperpage ==
630 		    prevqc->qc_cache->pc_pool.pr_itemsperpage) {
631 			pool_cache_destroy(qc->qc_cache);
632 			vm->vm_qcache[i - 1] = prevqc;
633 			continue;
634 		}
635 		qc->qc_cache->pc_pool.pr_qcache = qc;
636 		vm->vm_qcache[i - 1] = qc;
637 		prevqc = qc;
638 	}
639 }
640 
641 static void
642 qc_destroy(vmem_t *vm)
643 {
644 	const qcache_t *prevqc;
645 	int i;
646 	int qcache_idx_max;
647 
648 	qcache_idx_max = vm->vm_qcache_max >> vm->vm_quantum_shift;
649 	prevqc = NULL;
650 	for (i = 0; i < qcache_idx_max; i++) {
651 		qcache_t *qc = vm->vm_qcache[i];
652 
653 		if (prevqc == qc) {
654 			continue;
655 		}
656 		pool_cache_destroy(qc->qc_cache);
657 		prevqc = qc;
658 	}
659 }
660 #endif
661 
662 #if defined(_KERNEL)
663 static void
664 vmem_bootstrap(void)
665 {
666 
667 	mutex_init(&vmem_list_lock, MUTEX_DEFAULT, IPL_NONE);
668 	mutex_init(&vmem_btag_lock, MUTEX_DEFAULT, IPL_VM);
669 	mutex_init(&vmem_btag_refill_lock, MUTEX_DEFAULT, IPL_VM);
670 
671 	while (static_bt_count-- > 0) {
672 		bt_t *bt = &static_bts[static_bt_count];
673 		LIST_INSERT_HEAD(&vmem_btag_freelist, bt, bt_freelist);
674 		VMEM_EVCNT_INCR(static_bt_count);
675 		vmem_btag_freelist_count++;
676 	}
677 	vmem_bootstrapped = TRUE;
678 }
679 
680 void
681 vmem_subsystem_init(vmem_t *vm)
682 {
683 
684 	kmem_va_meta_arena = vmem_init(&kmem_va_meta_arena_store, "vmem-va",
685 	    0, 0, PAGE_SIZE, vmem_alloc, vmem_free, vm,
686 	    0, VM_NOSLEEP | VM_BOOTSTRAP | VM_LARGEIMPORT,
687 	    IPL_VM);
688 
689 	kmem_meta_arena = vmem_init(&kmem_meta_arena_store, "vmem-meta",
690 	    0, 0, PAGE_SIZE,
691 	    uvm_km_kmem_alloc, uvm_km_kmem_free, kmem_va_meta_arena,
692 	    0, VM_NOSLEEP | VM_BOOTSTRAP, IPL_VM);
693 
694 	pool_init(&vmem_btag_pool, sizeof(bt_t), coherency_unit, 0,
695 	    PR_PHINPAGE, "vmembt", &pool_allocator_vmem_meta, IPL_VM);
696 }
697 #endif /* defined(_KERNEL) */
698 
699 static int
700 vmem_add1(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, vm_flag_t flags,
701     int spanbttype)
702 {
703 	bt_t *btspan;
704 	bt_t *btfree;
705 
706 	VMEM_ASSERT_LOCKED(vm);
707 	KASSERT((flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
708 	KASSERT((~flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
709 	KASSERT(spanbttype == BT_TYPE_SPAN ||
710 	    spanbttype == BT_TYPE_SPAN_STATIC);
711 
712 	btspan = bt_alloc(vm, flags);
713 	if (btspan == NULL) {
714 		return ENOMEM;
715 	}
716 	btfree = bt_alloc(vm, flags);
717 	if (btfree == NULL) {
718 		bt_free(vm, btspan);
719 		return ENOMEM;
720 	}
721 
722 	btspan->bt_type = spanbttype;
723 	btspan->bt_start = addr;
724 	btspan->bt_size = size;
725 
726 	btfree->bt_type = BT_TYPE_FREE;
727 	btfree->bt_start = addr;
728 	btfree->bt_size = size;
729 
730 	bt_insseg_tail(vm, btspan);
731 	bt_insseg(vm, btfree, btspan);
732 	bt_insfree(vm, btfree);
733 	vm->vm_size += size;
734 
735 	return 0;
736 }
737 
738 static void
739 vmem_destroy1(vmem_t *vm)
740 {
741 
742 #if defined(QCACHE)
743 	qc_destroy(vm);
744 #endif /* defined(QCACHE) */
745 	VMEM_LOCK(vm);
746 
747 	for (int i = 0; i < vm->vm_hashsize; i++) {
748 		bt_t *bt;
749 
750 		while ((bt = LIST_FIRST(&vm->vm_hashlist[i])) != NULL) {
751 			KASSERT(bt->bt_type == BT_TYPE_SPAN_STATIC);
752 			LIST_REMOVE(bt, bt_hashlist);
753 			bt_free(vm, bt);
754 		}
755 	}
756 
757 	/* bt_freetrim() drops the lock. */
758 	bt_freetrim(vm, 0);
759 	if (vm->vm_hashlist != &vm->vm_hash0) {
760 		xfree(vm->vm_hashlist,
761 		    sizeof(struct vmem_hashlist) * vm->vm_hashsize);
762 	}
763 
764 	VMEM_CONDVAR_DESTROY(vm);
765 	VMEM_LOCK_DESTROY(vm);
766 	xfree(vm, sizeof(*vm));
767 }
768 
769 static int
770 vmem_import(vmem_t *vm, vmem_size_t size, vm_flag_t flags)
771 {
772 	vmem_addr_t addr;
773 	int rc;
774 
775 	VMEM_ASSERT_LOCKED(vm);
776 
777 	if (vm->vm_importfn == NULL) {
778 		return EINVAL;
779 	}
780 
781 	if (vm->vm_flags & VM_LARGEIMPORT) {
782 		size *= 16;
783 	}
784 
785 	VMEM_UNLOCK(vm);
786 	if (vm->vm_flags & VM_XIMPORT) {
787 		rc = __FPTRCAST(vmem_ximport_t *, vm->vm_importfn)(vm->vm_arg,
788 		    size, &size, flags, &addr);
789 	} else {
790 		rc = (vm->vm_importfn)(vm->vm_arg, size, flags, &addr);
791 	}
792 	VMEM_LOCK(vm);
793 
794 	if (rc) {
795 		return ENOMEM;
796 	}
797 
798 	if (vmem_add1(vm, addr, size, flags, BT_TYPE_SPAN) != 0) {
799 		VMEM_UNLOCK(vm);
800 		(*vm->vm_releasefn)(vm->vm_arg, addr, size);
801 		VMEM_LOCK(vm);
802 		return ENOMEM;
803 	}
804 
805 	return 0;
806 }
807 
808 static int
809 vmem_rehash(vmem_t *vm, size_t newhashsize, vm_flag_t flags)
810 {
811 	bt_t *bt;
812 	int i;
813 	struct vmem_hashlist *newhashlist;
814 	struct vmem_hashlist *oldhashlist;
815 	size_t oldhashsize;
816 
817 	KASSERT(newhashsize > 0);
818 
819 	/* Round hash size up to a power of 2. */
820 	newhashsize = 1 << (ilog2(newhashsize) + 1);
821 
822 	newhashlist =
823 	    xmalloc(sizeof(struct vmem_hashlist) * newhashsize, flags);
824 	if (newhashlist == NULL) {
825 		return ENOMEM;
826 	}
827 	for (i = 0; i < newhashsize; i++) {
828 		LIST_INIT(&newhashlist[i]);
829 	}
830 
831 	VMEM_LOCK(vm);
832 	/* Decay back to a small hash slowly. */
833 	if (vm->vm_maxbusytag >= 2) {
834 		vm->vm_maxbusytag = vm->vm_maxbusytag / 2 - 1;
835 		if (vm->vm_nbusytag > vm->vm_maxbusytag) {
836 			vm->vm_maxbusytag = vm->vm_nbusytag;
837 		}
838 	} else {
839 		vm->vm_maxbusytag = vm->vm_nbusytag;
840 	}
841 	oldhashlist = vm->vm_hashlist;
842 	oldhashsize = vm->vm_hashsize;
843 	vm->vm_hashlist = newhashlist;
844 	vm->vm_hashsize = newhashsize;
845 	vm->vm_hashmask = newhashsize - 1;
846 	if (oldhashlist == NULL) {
847 		VMEM_UNLOCK(vm);
848 		return 0;
849 	}
850 	for (i = 0; i < oldhashsize; i++) {
851 		while ((bt = LIST_FIRST(&oldhashlist[i])) != NULL) {
852 			bt_rembusy(vm, bt); /* XXX */
853 			bt_insbusy(vm, bt);
854 		}
855 	}
856 	VMEM_UNLOCK(vm);
857 
858 	if (oldhashlist != &vm->vm_hash0) {
859 		xfree(oldhashlist,
860 		    sizeof(struct vmem_hashlist) * oldhashsize);
861 	}
862 
863 	return 0;
864 }
865 
866 /*
867  * vmem_fit: check if a bt can satisfy the given restrictions.
868  *
869  * it's a caller's responsibility to ensure the region is big enough
870  * before calling us.
871  */
872 
873 static int
874 vmem_fit(const bt_t *bt, vmem_size_t size, vmem_size_t align,
875     vmem_size_t phase, vmem_size_t nocross,
876     vmem_addr_t minaddr, vmem_addr_t maxaddr, vmem_addr_t *addrp)
877 {
878 	vmem_addr_t start;
879 	vmem_addr_t end;
880 
881 	KASSERT(size > 0);
882 	KASSERT(bt->bt_size >= size); /* caller's responsibility */
883 
884 	/*
885 	 * XXX assumption: vmem_addr_t and vmem_size_t are
886 	 * unsigned integer of the same size.
887 	 */
888 
889 	start = bt->bt_start;
890 	if (start < minaddr) {
891 		start = minaddr;
892 	}
893 	end = BT_END(bt);
894 	if (end > maxaddr) {
895 		end = maxaddr;
896 	}
897 	if (start > end) {
898 		return ENOMEM;
899 	}
900 
901 	start = VMEM_ALIGNUP(start - phase, align) + phase;
902 	if (start < bt->bt_start) {
903 		start += align;
904 	}
905 	if (VMEM_CROSS_P(start, start + size - 1, nocross)) {
906 		KASSERT(align < nocross);
907 		start = VMEM_ALIGNUP(start - phase, nocross) + phase;
908 	}
909 	if (start <= end && end - start >= size - 1) {
910 		KASSERT((start & (align - 1)) == phase);
911 		KASSERT(!VMEM_CROSS_P(start, start + size - 1, nocross));
912 		KASSERT(minaddr <= start);
913 		KASSERT(maxaddr == 0 || start + size - 1 <= maxaddr);
914 		KASSERT(bt->bt_start <= start);
915 		KASSERT(BT_END(bt) - start >= size - 1);
916 		*addrp = start;
917 		return 0;
918 	}
919 	return ENOMEM;
920 }
921 
922 /* ---- vmem API */
923 
924 /*
925  * vmem_init: creates a vmem arena.
926  */
927 
928 vmem_t *
929 vmem_init(vmem_t *vm, const char *name,
930     vmem_addr_t base, vmem_size_t size, vmem_size_t quantum,
931     vmem_import_t *importfn, vmem_release_t *releasefn,
932     vmem_t *arg, vmem_size_t qcache_max, vm_flag_t flags, int ipl)
933 {
934 	int i;
935 
936 	KASSERT((flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
937 	KASSERT((~flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
938 	KASSERT(quantum > 0);
939 
940 #if defined(_KERNEL)
941 	/* XXX: SMP, we get called early... */
942 	if (!vmem_bootstrapped) {
943 		vmem_bootstrap();
944 	}
945 #endif /* defined(_KERNEL) */
946 
947 	if (vm == NULL) {
948 		vm = xmalloc(sizeof(*vm), flags);
949 	}
950 	if (vm == NULL) {
951 		return NULL;
952 	}
953 
954 	VMEM_CONDVAR_INIT(vm, "vmem");
955 	VMEM_LOCK_INIT(vm, ipl);
956 	vm->vm_flags = flags;
957 	vm->vm_nfreetags = 0;
958 	LIST_INIT(&vm->vm_freetags);
959 	strlcpy(vm->vm_name, name, sizeof(vm->vm_name));
960 	vm->vm_quantum_mask = quantum - 1;
961 	vm->vm_quantum_shift = SIZE2ORDER(quantum);
962 	KASSERT(ORDER2SIZE(vm->vm_quantum_shift) == quantum);
963 	vm->vm_importfn = importfn;
964 	vm->vm_releasefn = releasefn;
965 	vm->vm_arg = arg;
966 	vm->vm_nbusytag = 0;
967 	vm->vm_maxbusytag = 0;
968 	vm->vm_size = 0;
969 	vm->vm_inuse = 0;
970 #if defined(QCACHE)
971 	qc_init(vm, qcache_max, ipl);
972 #endif /* defined(QCACHE) */
973 
974 	TAILQ_INIT(&vm->vm_seglist);
975 	for (i = 0; i < VMEM_MAXORDER; i++) {
976 		LIST_INIT(&vm->vm_freelist[i]);
977 	}
978 	memset(&vm->vm_hash0, 0, sizeof(vm->vm_hash0));
979 	vm->vm_hashsize = 1;
980 	vm->vm_hashmask = vm->vm_hashsize - 1;
981 	vm->vm_hashlist = &vm->vm_hash0;
982 
983 	if (size != 0) {
984 		if (vmem_add(vm, base, size, flags) != 0) {
985 			vmem_destroy1(vm);
986 			return NULL;
987 		}
988 	}
989 
990 #if defined(_KERNEL)
991 	if (flags & VM_BOOTSTRAP) {
992 		bt_refill(vm);
993 	}
994 
995 	mutex_enter(&vmem_list_lock);
996 	LIST_INSERT_HEAD(&vmem_list, vm, vm_alllist);
997 	mutex_exit(&vmem_list_lock);
998 #endif /* defined(_KERNEL) */
999 
1000 	return vm;
1001 }
1002 
1003 
1004 
1005 /*
1006  * vmem_create: create an arena.
1007  *
1008  * => must not be called from interrupt context.
1009  */
1010 
1011 vmem_t *
1012 vmem_create(const char *name, vmem_addr_t base, vmem_size_t size,
1013     vmem_size_t quantum, vmem_import_t *importfn, vmem_release_t *releasefn,
1014     vmem_t *source, vmem_size_t qcache_max, vm_flag_t flags, int ipl)
1015 {
1016 
1017 	KASSERT((flags & (VM_XIMPORT)) == 0);
1018 
1019 	return vmem_init(NULL, name, base, size, quantum,
1020 	    importfn, releasefn, source, qcache_max, flags, ipl);
1021 }
1022 
1023 /*
1024  * vmem_xcreate: create an arena takes alternative import func.
1025  *
1026  * => must not be called from interrupt context.
1027  */
1028 
1029 vmem_t *
1030 vmem_xcreate(const char *name, vmem_addr_t base, vmem_size_t size,
1031     vmem_size_t quantum, vmem_ximport_t *importfn, vmem_release_t *releasefn,
1032     vmem_t *source, vmem_size_t qcache_max, vm_flag_t flags, int ipl)
1033 {
1034 
1035 	KASSERT((flags & (VM_XIMPORT)) == 0);
1036 
1037 	return vmem_init(NULL, name, base, size, quantum,
1038 	    __FPTRCAST(vmem_import_t *, importfn), releasefn, source,
1039 	    qcache_max, flags | VM_XIMPORT, ipl);
1040 }
1041 
1042 void
1043 vmem_destroy(vmem_t *vm)
1044 {
1045 
1046 #if defined(_KERNEL)
1047 	mutex_enter(&vmem_list_lock);
1048 	LIST_REMOVE(vm, vm_alllist);
1049 	mutex_exit(&vmem_list_lock);
1050 #endif /* defined(_KERNEL) */
1051 
1052 	vmem_destroy1(vm);
1053 }
1054 
1055 vmem_size_t
1056 vmem_roundup_size(vmem_t *vm, vmem_size_t size)
1057 {
1058 
1059 	return (size + vm->vm_quantum_mask) & ~vm->vm_quantum_mask;
1060 }
1061 
1062 /*
1063  * vmem_alloc: allocate resource from the arena.
1064  */
1065 
1066 int
1067 vmem_alloc(vmem_t *vm, vmem_size_t size, vm_flag_t flags, vmem_addr_t *addrp)
1068 {
1069 	const vm_flag_t strat __diagused = flags & VM_FITMASK;
1070 	int error;
1071 
1072 	KASSERT((flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
1073 	KASSERT((~flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
1074 
1075 	KASSERT(size > 0);
1076 	KASSERT(strat == VM_BESTFIT || strat == VM_INSTANTFIT);
1077 	if ((flags & VM_SLEEP) != 0) {
1078 		ASSERT_SLEEPABLE();
1079 	}
1080 
1081 #if defined(QCACHE)
1082 	if (size <= vm->vm_qcache_max) {
1083 		void *p;
1084 		int qidx = (size + vm->vm_quantum_mask) >> vm->vm_quantum_shift;
1085 		qcache_t *qc = vm->vm_qcache[qidx - 1];
1086 
1087 		p = pool_cache_get(qc->qc_cache, vmf_to_prf(flags));
1088 		if (addrp != NULL)
1089 			*addrp = (vmem_addr_t)p;
1090 		error = (p == NULL) ? ENOMEM : 0;
1091 		goto out;
1092 	}
1093 #endif /* defined(QCACHE) */
1094 
1095 	error = vmem_xalloc(vm, size, 0, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX,
1096 	    flags, addrp);
1097 out:
1098 	KASSERT(error == 0 || (flags & VM_SLEEP) == 0);
1099 	return error;
1100 }
1101 
1102 int
1103 vmem_xalloc(vmem_t *vm, const vmem_size_t size0, vmem_size_t align,
1104     const vmem_size_t phase, const vmem_size_t nocross,
1105     const vmem_addr_t minaddr, const vmem_addr_t maxaddr, const vm_flag_t flags,
1106     vmem_addr_t *addrp)
1107 {
1108 	struct vmem_freelist *list;
1109 	struct vmem_freelist *first;
1110 	struct vmem_freelist *end;
1111 	bt_t *bt;
1112 	bt_t *btnew;
1113 	bt_t *btnew2;
1114 	const vmem_size_t size = vmem_roundup_size(vm, size0);
1115 	vm_flag_t strat = flags & VM_FITMASK;
1116 	vmem_addr_t start;
1117 	int rc;
1118 
1119 	KASSERT(size0 > 0);
1120 	KASSERT(size > 0);
1121 	KASSERT(strat == VM_BESTFIT || strat == VM_INSTANTFIT);
1122 	if ((flags & VM_SLEEP) != 0) {
1123 		ASSERT_SLEEPABLE();
1124 	}
1125 	KASSERT((align & vm->vm_quantum_mask) == 0);
1126 	KASSERT((align & (align - 1)) == 0);
1127 	KASSERT((phase & vm->vm_quantum_mask) == 0);
1128 	KASSERT((nocross & vm->vm_quantum_mask) == 0);
1129 	KASSERT((nocross & (nocross - 1)) == 0);
1130 	KASSERT((align == 0 && phase == 0) || phase < align);
1131 	KASSERT(nocross == 0 || nocross >= size);
1132 	KASSERT(minaddr <= maxaddr);
1133 	KASSERT(!VMEM_CROSS_P(phase, phase + size - 1, nocross));
1134 
1135 	if (align == 0) {
1136 		align = vm->vm_quantum_mask + 1;
1137 	}
1138 
1139 	/*
1140 	 * allocate boundary tags before acquiring the vmem lock.
1141 	 */
1142 	VMEM_LOCK(vm);
1143 	btnew = bt_alloc(vm, flags);
1144 	if (btnew == NULL) {
1145 		VMEM_UNLOCK(vm);
1146 		return ENOMEM;
1147 	}
1148 	btnew2 = bt_alloc(vm, flags); /* XXX not necessary if no restrictions */
1149 	if (btnew2 == NULL) {
1150 		bt_free(vm, btnew);
1151 		VMEM_UNLOCK(vm);
1152 		return ENOMEM;
1153 	}
1154 
1155 	/*
1156 	 * choose a free block from which we allocate.
1157 	 */
1158 retry_strat:
1159 	first = bt_freehead_toalloc(vm, size, strat);
1160 	end = &vm->vm_freelist[VMEM_MAXORDER];
1161 retry:
1162 	bt = NULL;
1163 	vmem_check(vm);
1164 	if (strat == VM_INSTANTFIT) {
1165 		/*
1166 		 * just choose the first block which satisfies our restrictions.
1167 		 *
1168 		 * note that we don't need to check the size of the blocks
1169 		 * because any blocks found on these list should be larger than
1170 		 * the given size.
1171 		 */
1172 		for (list = first; list < end; list++) {
1173 			bt = LIST_FIRST(list);
1174 			if (bt != NULL) {
1175 				rc = vmem_fit(bt, size, align, phase,
1176 				    nocross, minaddr, maxaddr, &start);
1177 				if (rc == 0) {
1178 					goto gotit;
1179 				}
1180 				/*
1181 				 * don't bother to follow the bt_freelist link
1182 				 * here.  the list can be very long and we are
1183 				 * told to run fast.  blocks from the later free
1184 				 * lists are larger and have better chances to
1185 				 * satisfy our restrictions.
1186 				 */
1187 			}
1188 		}
1189 	} else { /* VM_BESTFIT */
1190 		/*
1191 		 * we assume that, for space efficiency, it's better to
1192 		 * allocate from a smaller block.  thus we will start searching
1193 		 * from the lower-order list than VM_INSTANTFIT.
1194 		 * however, don't bother to find the smallest block in a free
1195 		 * list because the list can be very long.  we can revisit it
1196 		 * if/when it turns out to be a problem.
1197 		 *
1198 		 * note that the 'first' list can contain blocks smaller than
1199 		 * the requested size.  thus we need to check bt_size.
1200 		 */
1201 		for (list = first; list < end; list++) {
1202 			LIST_FOREACH(bt, list, bt_freelist) {
1203 				if (bt->bt_size >= size) {
1204 					rc = vmem_fit(bt, size, align, phase,
1205 					    nocross, minaddr, maxaddr, &start);
1206 					if (rc == 0) {
1207 						goto gotit;
1208 					}
1209 				}
1210 			}
1211 		}
1212 	}
1213 #if 1
1214 	if (strat == VM_INSTANTFIT) {
1215 		strat = VM_BESTFIT;
1216 		goto retry_strat;
1217 	}
1218 #endif
1219 	if (align != vm->vm_quantum_mask + 1 || phase != 0 || nocross != 0) {
1220 
1221 		/*
1222 		 * XXX should try to import a region large enough to
1223 		 * satisfy restrictions?
1224 		 */
1225 
1226 		goto fail;
1227 	}
1228 	/* XXX eeek, minaddr & maxaddr not respected */
1229 	if (vmem_import(vm, size, flags) == 0) {
1230 		goto retry;
1231 	}
1232 	/* XXX */
1233 
1234 	if ((flags & VM_SLEEP) != 0) {
1235 		vmem_kick_pdaemon();
1236 		VMEM_CONDVAR_WAIT(vm);
1237 		goto retry;
1238 	}
1239 fail:
1240 	bt_free(vm, btnew);
1241 	bt_free(vm, btnew2);
1242 	VMEM_UNLOCK(vm);
1243 	return ENOMEM;
1244 
1245 gotit:
1246 	KASSERT(bt->bt_type == BT_TYPE_FREE);
1247 	KASSERT(bt->bt_size >= size);
1248 	bt_remfree(vm, bt);
1249 	vmem_check(vm);
1250 	if (bt->bt_start != start) {
1251 		btnew2->bt_type = BT_TYPE_FREE;
1252 		btnew2->bt_start = bt->bt_start;
1253 		btnew2->bt_size = start - bt->bt_start;
1254 		bt->bt_start = start;
1255 		bt->bt_size -= btnew2->bt_size;
1256 		bt_insfree(vm, btnew2);
1257 		bt_insseg(vm, btnew2, TAILQ_PREV(bt, vmem_seglist, bt_seglist));
1258 		btnew2 = NULL;
1259 		vmem_check(vm);
1260 	}
1261 	KASSERT(bt->bt_start == start);
1262 	if (bt->bt_size != size && bt->bt_size - size > vm->vm_quantum_mask) {
1263 		/* split */
1264 		btnew->bt_type = BT_TYPE_BUSY;
1265 		btnew->bt_start = bt->bt_start;
1266 		btnew->bt_size = size;
1267 		bt->bt_start = bt->bt_start + size;
1268 		bt->bt_size -= size;
1269 		bt_insfree(vm, bt);
1270 		bt_insseg(vm, btnew, TAILQ_PREV(bt, vmem_seglist, bt_seglist));
1271 		bt_insbusy(vm, btnew);
1272 		vmem_check(vm);
1273 	} else {
1274 		bt->bt_type = BT_TYPE_BUSY;
1275 		bt_insbusy(vm, bt);
1276 		vmem_check(vm);
1277 		bt_free(vm, btnew);
1278 		btnew = bt;
1279 	}
1280 	if (btnew2 != NULL) {
1281 		bt_free(vm, btnew2);
1282 	}
1283 	KASSERT(btnew->bt_size >= size);
1284 	btnew->bt_type = BT_TYPE_BUSY;
1285 	if (addrp != NULL)
1286 		*addrp = btnew->bt_start;
1287 	VMEM_UNLOCK(vm);
1288 	return 0;
1289 }
1290 
1291 /*
1292  * vmem_free: free the resource to the arena.
1293  */
1294 
1295 void
1296 vmem_free(vmem_t *vm, vmem_addr_t addr, vmem_size_t size)
1297 {
1298 
1299 	KASSERT(size > 0);
1300 
1301 #if defined(QCACHE)
1302 	if (size <= vm->vm_qcache_max) {
1303 		int qidx = (size + vm->vm_quantum_mask) >> vm->vm_quantum_shift;
1304 		qcache_t *qc = vm->vm_qcache[qidx - 1];
1305 
1306 		pool_cache_put(qc->qc_cache, (void *)addr);
1307 		return;
1308 	}
1309 #endif /* defined(QCACHE) */
1310 
1311 	vmem_xfree(vm, addr, size);
1312 }
1313 
1314 void
1315 vmem_xfree(vmem_t *vm, vmem_addr_t addr, vmem_size_t size)
1316 {
1317 	bt_t *bt;
1318 
1319 	KASSERT(size > 0);
1320 
1321 	VMEM_LOCK(vm);
1322 
1323 	bt = bt_lookupbusy(vm, addr);
1324 	KASSERT(bt != NULL);
1325 	KASSERT(bt->bt_start == addr);
1326 	KASSERT(bt->bt_size == vmem_roundup_size(vm, size) ||
1327 	    bt->bt_size - vmem_roundup_size(vm, size) <= vm->vm_quantum_mask);
1328 
1329 	/* vmem_xfree_bt() drops the lock. */
1330 	vmem_xfree_bt(vm, bt);
1331 }
1332 
1333 void
1334 vmem_xfreeall(vmem_t *vm)
1335 {
1336 	bt_t *bt;
1337 
1338 	/* This can't be used if the arena has a quantum cache. */
1339 	KASSERT(vm->vm_qcache_max == 0);
1340 
1341 	for (;;) {
1342 		VMEM_LOCK(vm);
1343 		TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1344 			if (bt->bt_type == BT_TYPE_BUSY)
1345 				break;
1346 		}
1347 		if (bt != NULL) {
1348 			/* vmem_xfree_bt() drops the lock. */
1349 			vmem_xfree_bt(vm, bt);
1350 		} else {
1351 			VMEM_UNLOCK(vm);
1352 			return;
1353 		}
1354 	}
1355 }
1356 
1357 static void
1358 vmem_xfree_bt(vmem_t *vm, bt_t *bt)
1359 {
1360 	bt_t *t;
1361 
1362 	VMEM_ASSERT_LOCKED(vm);
1363 
1364 	KASSERT(bt->bt_type == BT_TYPE_BUSY);
1365 	bt_rembusy(vm, bt);
1366 	bt->bt_type = BT_TYPE_FREE;
1367 
1368 	/* coalesce */
1369 	t = TAILQ_NEXT(bt, bt_seglist);
1370 	if (t != NULL && t->bt_type == BT_TYPE_FREE) {
1371 		KASSERT(BT_END(bt) < t->bt_start);	/* YYY */
1372 		bt_remfree(vm, t);
1373 		bt_remseg(vm, t);
1374 		bt->bt_size += t->bt_size;
1375 		bt_free(vm, t);
1376 	}
1377 	t = TAILQ_PREV(bt, vmem_seglist, bt_seglist);
1378 	if (t != NULL && t->bt_type == BT_TYPE_FREE) {
1379 		KASSERT(BT_END(t) < bt->bt_start);	/* YYY */
1380 		bt_remfree(vm, t);
1381 		bt_remseg(vm, t);
1382 		bt->bt_size += t->bt_size;
1383 		bt->bt_start = t->bt_start;
1384 		bt_free(vm, t);
1385 	}
1386 
1387 	t = TAILQ_PREV(bt, vmem_seglist, bt_seglist);
1388 	KASSERT(t != NULL);
1389 	KASSERT(BT_ISSPAN_P(t) || t->bt_type == BT_TYPE_BUSY);
1390 	if (vm->vm_releasefn != NULL && t->bt_type == BT_TYPE_SPAN &&
1391 	    t->bt_size == bt->bt_size) {
1392 		vmem_addr_t spanaddr;
1393 		vmem_size_t spansize;
1394 
1395 		KASSERT(t->bt_start == bt->bt_start);
1396 		spanaddr = bt->bt_start;
1397 		spansize = bt->bt_size;
1398 		bt_remseg(vm, bt);
1399 		bt_free(vm, bt);
1400 		bt_remseg(vm, t);
1401 		bt_free(vm, t);
1402 		vm->vm_size -= spansize;
1403 		VMEM_CONDVAR_BROADCAST(vm);
1404 		/* bt_freetrim() drops the lock. */
1405 		bt_freetrim(vm, BT_MAXFREE);
1406 		(*vm->vm_releasefn)(vm->vm_arg, spanaddr, spansize);
1407 	} else {
1408 		bt_insfree(vm, bt);
1409 		VMEM_CONDVAR_BROADCAST(vm);
1410 		/* bt_freetrim() drops the lock. */
1411 		bt_freetrim(vm, BT_MAXFREE);
1412 	}
1413 }
1414 
1415 /*
1416  * vmem_add:
1417  *
1418  * => caller must ensure appropriate spl,
1419  *    if the arena can be accessed from interrupt context.
1420  */
1421 
1422 int
1423 vmem_add(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, vm_flag_t flags)
1424 {
1425 	int rv;
1426 
1427 	VMEM_LOCK(vm);
1428 	rv = vmem_add1(vm, addr, size, flags, BT_TYPE_SPAN_STATIC);
1429 	VMEM_UNLOCK(vm);
1430 
1431 	return rv;
1432 }
1433 
1434 /*
1435  * vmem_size: information about arenas size
1436  *
1437  * => return free/allocated size in arena
1438  */
1439 vmem_size_t
1440 vmem_size(vmem_t *vm, int typemask)
1441 {
1442 
1443 	switch (typemask) {
1444 	case VMEM_ALLOC:
1445 		return vm->vm_inuse;
1446 	case VMEM_FREE:
1447 		return vm->vm_size - vm->vm_inuse;
1448 	case VMEM_FREE|VMEM_ALLOC:
1449 		return vm->vm_size;
1450 	default:
1451 		panic("vmem_size");
1452 	}
1453 }
1454 
1455 /* ---- rehash */
1456 
1457 #if defined(_KERNEL)
1458 static struct callout vmem_rehash_ch;
1459 static int vmem_rehash_interval;
1460 static struct workqueue *vmem_rehash_wq;
1461 static struct work vmem_rehash_wk;
1462 
1463 static void
1464 vmem_rehash_all(struct work *wk, void *dummy)
1465 {
1466 	vmem_t *vm;
1467 
1468 	KASSERT(wk == &vmem_rehash_wk);
1469 	mutex_enter(&vmem_list_lock);
1470 	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1471 		size_t desired;
1472 		size_t current;
1473 
1474 		desired = atomic_load_relaxed(&vm->vm_maxbusytag);
1475 		current = atomic_load_relaxed(&vm->vm_hashsize);
1476 
1477 		if (desired > VMEM_HASHSIZE_MAX) {
1478 			desired = VMEM_HASHSIZE_MAX;
1479 		} else if (desired < VMEM_HASHSIZE_MIN) {
1480 			desired = VMEM_HASHSIZE_MIN;
1481 		}
1482 		if (desired > current * 2 || desired * 2 < current) {
1483 			vmem_rehash(vm, desired, VM_NOSLEEP);
1484 		}
1485 	}
1486 	mutex_exit(&vmem_list_lock);
1487 
1488 	callout_schedule(&vmem_rehash_ch, vmem_rehash_interval);
1489 }
1490 
1491 static void
1492 vmem_rehash_all_kick(void *dummy)
1493 {
1494 
1495 	workqueue_enqueue(vmem_rehash_wq, &vmem_rehash_wk, NULL);
1496 }
1497 
1498 void
1499 vmem_rehash_start(void)
1500 {
1501 	int error;
1502 
1503 	error = workqueue_create(&vmem_rehash_wq, "vmem_rehash",
1504 	    vmem_rehash_all, NULL, PRI_VM, IPL_SOFTCLOCK, WQ_MPSAFE);
1505 	if (error) {
1506 		panic("%s: workqueue_create %d\n", __func__, error);
1507 	}
1508 	callout_init(&vmem_rehash_ch, CALLOUT_MPSAFE);
1509 	callout_setfunc(&vmem_rehash_ch, vmem_rehash_all_kick, NULL);
1510 
1511 	vmem_rehash_interval = hz * 10;
1512 	callout_schedule(&vmem_rehash_ch, vmem_rehash_interval);
1513 }
1514 #endif /* defined(_KERNEL) */
1515 
1516 /* ---- debug */
1517 
1518 #if defined(DDB) || defined(UNITTEST) || defined(VMEM_SANITY)
1519 
1520 static void bt_dump(const bt_t *, void (*)(const char *, ...)
1521     __printflike(1, 2));
1522 
1523 static const char *
1524 bt_type_string(int type)
1525 {
1526 	static const char * const table[] = {
1527 		[BT_TYPE_BUSY] = "busy",
1528 		[BT_TYPE_FREE] = "free",
1529 		[BT_TYPE_SPAN] = "span",
1530 		[BT_TYPE_SPAN_STATIC] = "static span",
1531 	};
1532 
1533 	if (type >= __arraycount(table)) {
1534 		return "BOGUS";
1535 	}
1536 	return table[type];
1537 }
1538 
1539 static void
1540 bt_dump(const bt_t *bt, void (*pr)(const char *, ...))
1541 {
1542 
1543 	(*pr)("\t%p: %" PRIu64 ", %" PRIu64 ", %d(%s)\n",
1544 	    bt, (uint64_t)bt->bt_start, (uint64_t)bt->bt_size,
1545 	    bt->bt_type, bt_type_string(bt->bt_type));
1546 }
1547 
1548 static void
1549 vmem_dump(const vmem_t *vm , void (*pr)(const char *, ...) __printflike(1, 2))
1550 {
1551 	const bt_t *bt;
1552 	int i;
1553 
1554 	(*pr)("vmem %p '%s'\n", vm, vm->vm_name);
1555 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1556 		bt_dump(bt, pr);
1557 	}
1558 
1559 	for (i = 0; i < VMEM_MAXORDER; i++) {
1560 		const struct vmem_freelist *fl = &vm->vm_freelist[i];
1561 
1562 		if (LIST_EMPTY(fl)) {
1563 			continue;
1564 		}
1565 
1566 		(*pr)("freelist[%d]\n", i);
1567 		LIST_FOREACH(bt, fl, bt_freelist) {
1568 			bt_dump(bt, pr);
1569 		}
1570 	}
1571 }
1572 
1573 #endif /* defined(DDB) || defined(UNITTEST) || defined(VMEM_SANITY) */
1574 
1575 #if defined(DDB)
1576 static bt_t *
1577 vmem_whatis_lookup(vmem_t *vm, uintptr_t addr)
1578 {
1579 	bt_t *bt;
1580 
1581 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1582 		if (BT_ISSPAN_P(bt)) {
1583 			continue;
1584 		}
1585 		if (bt->bt_start <= addr && addr <= BT_END(bt)) {
1586 			return bt;
1587 		}
1588 	}
1589 
1590 	return NULL;
1591 }
1592 
1593 void
1594 vmem_whatis(uintptr_t addr, void (*pr)(const char *, ...))
1595 {
1596 	vmem_t *vm;
1597 
1598 	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1599 		bt_t *bt;
1600 
1601 		bt = vmem_whatis_lookup(vm, addr);
1602 		if (bt == NULL) {
1603 			continue;
1604 		}
1605 		(*pr)("%p is %p+%zu in VMEM '%s' (%s)\n",
1606 		    (void *)addr, (void *)bt->bt_start,
1607 		    (size_t)(addr - bt->bt_start), vm->vm_name,
1608 		    (bt->bt_type == BT_TYPE_BUSY) ? "allocated" : "free");
1609 	}
1610 }
1611 
1612 void
1613 vmem_printall(const char *modif, void (*pr)(const char *, ...))
1614 {
1615 	const vmem_t *vm;
1616 
1617 	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1618 		vmem_dump(vm, pr);
1619 	}
1620 }
1621 
1622 void
1623 vmem_print(uintptr_t addr, const char *modif, void (*pr)(const char *, ...))
1624 {
1625 	const vmem_t *vm = (const void *)addr;
1626 
1627 	vmem_dump(vm, pr);
1628 }
1629 #endif /* defined(DDB) */
1630 
1631 #if defined(_KERNEL)
1632 #define vmem_printf printf
1633 #else
1634 #include <stdio.h>
1635 #include <stdarg.h>
1636 
1637 static void
1638 vmem_printf(const char *fmt, ...)
1639 {
1640 	va_list ap;
1641 	va_start(ap, fmt);
1642 	vprintf(fmt, ap);
1643 	va_end(ap);
1644 }
1645 #endif
1646 
1647 #if defined(VMEM_SANITY)
1648 
1649 static bool
1650 vmem_check_sanity(vmem_t *vm)
1651 {
1652 	const bt_t *bt, *bt2;
1653 
1654 	KASSERT(vm != NULL);
1655 
1656 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1657 		if (bt->bt_start > BT_END(bt)) {
1658 			printf("corrupted tag\n");
1659 			bt_dump(bt, vmem_printf);
1660 			return false;
1661 		}
1662 	}
1663 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1664 		TAILQ_FOREACH(bt2, &vm->vm_seglist, bt_seglist) {
1665 			if (bt == bt2) {
1666 				continue;
1667 			}
1668 			if (BT_ISSPAN_P(bt) != BT_ISSPAN_P(bt2)) {
1669 				continue;
1670 			}
1671 			if (bt->bt_start <= BT_END(bt2) &&
1672 			    bt2->bt_start <= BT_END(bt)) {
1673 				printf("overwrapped tags\n");
1674 				bt_dump(bt, vmem_printf);
1675 				bt_dump(bt2, vmem_printf);
1676 				return false;
1677 			}
1678 		}
1679 	}
1680 
1681 	return true;
1682 }
1683 
1684 static void
1685 vmem_check(vmem_t *vm)
1686 {
1687 
1688 	if (!vmem_check_sanity(vm)) {
1689 		panic("insanity vmem %p", vm);
1690 	}
1691 }
1692 
1693 #endif /* defined(VMEM_SANITY) */
1694 
1695 #if defined(UNITTEST)
1696 int
1697 main(void)
1698 {
1699 	int rc;
1700 	vmem_t *vm;
1701 	vmem_addr_t p;
1702 	struct reg {
1703 		vmem_addr_t p;
1704 		vmem_size_t sz;
1705 		bool x;
1706 	} *reg = NULL;
1707 	int nreg = 0;
1708 	int nalloc = 0;
1709 	int nfree = 0;
1710 	vmem_size_t total = 0;
1711 #if 1
1712 	vm_flag_t strat = VM_INSTANTFIT;
1713 #else
1714 	vm_flag_t strat = VM_BESTFIT;
1715 #endif
1716 
1717 	vm = vmem_create("test", 0, 0, 1, NULL, NULL, NULL, 0, VM_SLEEP,
1718 #ifdef _KERNEL
1719 	    IPL_NONE
1720 #else
1721 	    0
1722 #endif
1723 	    );
1724 	if (vm == NULL) {
1725 		printf("vmem_create\n");
1726 		exit(EXIT_FAILURE);
1727 	}
1728 	vmem_dump(vm, vmem_printf);
1729 
1730 	rc = vmem_add(vm, 0, 50, VM_SLEEP);
1731 	assert(rc == 0);
1732 	rc = vmem_add(vm, 100, 200, VM_SLEEP);
1733 	assert(rc == 0);
1734 	rc = vmem_add(vm, 2000, 1, VM_SLEEP);
1735 	assert(rc == 0);
1736 	rc = vmem_add(vm, 40000, 65536, VM_SLEEP);
1737 	assert(rc == 0);
1738 	rc = vmem_add(vm, 10000, 10000, VM_SLEEP);
1739 	assert(rc == 0);
1740 	rc = vmem_add(vm, 500, 1000, VM_SLEEP);
1741 	assert(rc == 0);
1742 	rc = vmem_add(vm, 0xffffff00, 0x100, VM_SLEEP);
1743 	assert(rc == 0);
1744 	rc = vmem_xalloc(vm, 0x101, 0, 0, 0,
1745 	    0xffffff00, 0xffffffff, strat|VM_SLEEP, &p);
1746 	assert(rc != 0);
1747 	rc = vmem_xalloc(vm, 50, 0, 0, 0, 0, 49, strat|VM_SLEEP, &p);
1748 	assert(rc == 0 && p == 0);
1749 	vmem_xfree(vm, p, 50);
1750 	rc = vmem_xalloc(vm, 25, 0, 0, 0, 0, 24, strat|VM_SLEEP, &p);
1751 	assert(rc == 0 && p == 0);
1752 	rc = vmem_xalloc(vm, 0x100, 0, 0, 0,
1753 	    0xffffff01, 0xffffffff, strat|VM_SLEEP, &p);
1754 	assert(rc != 0);
1755 	rc = vmem_xalloc(vm, 0x100, 0, 0, 0,
1756 	    0xffffff00, 0xfffffffe, strat|VM_SLEEP, &p);
1757 	assert(rc != 0);
1758 	rc = vmem_xalloc(vm, 0x100, 0, 0, 0,
1759 	    0xffffff00, 0xffffffff, strat|VM_SLEEP, &p);
1760 	assert(rc == 0);
1761 	vmem_dump(vm, vmem_printf);
1762 	for (;;) {
1763 		struct reg *r;
1764 		int t = rand() % 100;
1765 
1766 		if (t > 45) {
1767 			/* alloc */
1768 			vmem_size_t sz = rand() % 500 + 1;
1769 			bool x;
1770 			vmem_size_t align, phase, nocross;
1771 			vmem_addr_t minaddr, maxaddr;
1772 
1773 			if (t > 70) {
1774 				x = true;
1775 				/* XXX */
1776 				align = 1 << (rand() % 15);
1777 				phase = rand() % 65536;
1778 				nocross = 1 << (rand() % 15);
1779 				if (align <= phase) {
1780 					phase = 0;
1781 				}
1782 				if (VMEM_CROSS_P(phase, phase + sz - 1,
1783 				    nocross)) {
1784 					nocross = 0;
1785 				}
1786 				do {
1787 					minaddr = rand() % 50000;
1788 					maxaddr = rand() % 70000;
1789 				} while (minaddr > maxaddr);
1790 				printf("=== xalloc %" PRIu64
1791 				    " align=%" PRIu64 ", phase=%" PRIu64
1792 				    ", nocross=%" PRIu64 ", min=%" PRIu64
1793 				    ", max=%" PRIu64 "\n",
1794 				    (uint64_t)sz,
1795 				    (uint64_t)align,
1796 				    (uint64_t)phase,
1797 				    (uint64_t)nocross,
1798 				    (uint64_t)minaddr,
1799 				    (uint64_t)maxaddr);
1800 				rc = vmem_xalloc(vm, sz, align, phase, nocross,
1801 				    minaddr, maxaddr, strat|VM_SLEEP, &p);
1802 			} else {
1803 				x = false;
1804 				printf("=== alloc %" PRIu64 "\n", (uint64_t)sz);
1805 				rc = vmem_alloc(vm, sz, strat|VM_SLEEP, &p);
1806 			}
1807 			printf("-> %" PRIu64 "\n", (uint64_t)p);
1808 			vmem_dump(vm, vmem_printf);
1809 			if (rc != 0) {
1810 				if (x) {
1811 					continue;
1812 				}
1813 				break;
1814 			}
1815 			nreg++;
1816 			reg = realloc(reg, sizeof(*reg) * nreg);
1817 			r = &reg[nreg - 1];
1818 			r->p = p;
1819 			r->sz = sz;
1820 			r->x = x;
1821 			total += sz;
1822 			nalloc++;
1823 		} else if (nreg != 0) {
1824 			/* free */
1825 			r = &reg[rand() % nreg];
1826 			printf("=== free %" PRIu64 ", %" PRIu64 "\n",
1827 			    (uint64_t)r->p, (uint64_t)r->sz);
1828 			if (r->x) {
1829 				vmem_xfree(vm, r->p, r->sz);
1830 			} else {
1831 				vmem_free(vm, r->p, r->sz);
1832 			}
1833 			total -= r->sz;
1834 			vmem_dump(vm, vmem_printf);
1835 			*r = reg[nreg - 1];
1836 			nreg--;
1837 			nfree++;
1838 		}
1839 		printf("total=%" PRIu64 "\n", (uint64_t)total);
1840 	}
1841 	fprintf(stderr, "total=%" PRIu64 ", nalloc=%d, nfree=%d\n",
1842 	    (uint64_t)total, nalloc, nfree);
1843 	exit(EXIT_SUCCESS);
1844 }
1845 #endif /* defined(UNITTEST) */
1846