xref: /netbsd-src/sys/kern/subr_vmem.c (revision deb6f0161a9109e7de9b519dc8dfb9478668dcdd)
1 /*	$NetBSD: subr_vmem.c,v 1.97 2018/02/08 09:05:20 dholland 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 1.97 2018/02/08 09:05:20 dholland 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 boundry 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
198 vmem_kick_pdaemon(void)
199 {
200 #if defined(_KERNEL)
201 	mutex_spin_enter(&uvm_fpageqlock);
202 	uvm_kick_pdaemon();
203 	mutex_spin_exit(&uvm_fpageqlock);
204 #endif
205 }
206 
207 /* ---- boundary tag */
208 
209 static int bt_refill(vmem_t *vm);
210 
211 static void *
212 pool_page_alloc_vmem_meta(struct pool *pp, int flags)
213 {
214 	const vm_flag_t vflags = (flags & PR_WAITOK) ? VM_SLEEP: VM_NOSLEEP;
215 	vmem_addr_t va;
216 	int ret;
217 
218 	ret = vmem_alloc(kmem_meta_arena, pp->pr_alloc->pa_pagesz,
219 	    (vflags & ~VM_FITMASK) | VM_INSTANTFIT | VM_POPULATING, &va);
220 
221 	return ret ? NULL : (void *)va;
222 }
223 
224 static void
225 pool_page_free_vmem_meta(struct pool *pp, void *v)
226 {
227 
228 	vmem_free(kmem_meta_arena, (vmem_addr_t)v, pp->pr_alloc->pa_pagesz);
229 }
230 
231 /* allocator for vmem-pool metadata */
232 struct pool_allocator pool_allocator_vmem_meta = {
233 	.pa_alloc = pool_page_alloc_vmem_meta,
234 	.pa_free = pool_page_free_vmem_meta,
235 	.pa_pagesz = 0
236 };
237 
238 static int
239 bt_refill(vmem_t *vm)
240 {
241 	bt_t *bt;
242 
243 	VMEM_LOCK(vm);
244 	if (vm->vm_nfreetags > BT_MINRESERVE) {
245 		VMEM_UNLOCK(vm);
246 		return 0;
247 	}
248 
249 	mutex_enter(&vmem_btag_lock);
250 	while (!LIST_EMPTY(&vmem_btag_freelist) &&
251 	    vm->vm_nfreetags <= BT_MINRESERVE) {
252 		bt = LIST_FIRST(&vmem_btag_freelist);
253 		LIST_REMOVE(bt, bt_freelist);
254 		LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
255 		vm->vm_nfreetags++;
256 		vmem_btag_freelist_count--;
257 		VMEM_EVCNT_INCR(static_bt_inuse);
258 	}
259 	mutex_exit(&vmem_btag_lock);
260 
261 	while (vm->vm_nfreetags <= BT_MINRESERVE) {
262 		VMEM_UNLOCK(vm);
263 		mutex_enter(&vmem_btag_refill_lock);
264 		bt = pool_get(&vmem_btag_pool, PR_NOWAIT);
265 		mutex_exit(&vmem_btag_refill_lock);
266 		VMEM_LOCK(vm);
267 		if (bt == NULL)
268 			break;
269 		LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
270 		vm->vm_nfreetags++;
271 	}
272 
273 	if (vm->vm_nfreetags <= BT_MINRESERVE) {
274 		VMEM_UNLOCK(vm);
275 		return ENOMEM;
276 	}
277 
278 	VMEM_UNLOCK(vm);
279 
280 	if (kmem_meta_arena != NULL) {
281 		(void)bt_refill(kmem_arena);
282 		(void)bt_refill(kmem_va_meta_arena);
283 		(void)bt_refill(kmem_meta_arena);
284 	}
285 
286 	return 0;
287 }
288 
289 static bt_t *
290 bt_alloc(vmem_t *vm, vm_flag_t flags)
291 {
292 	bt_t *bt;
293 	VMEM_LOCK(vm);
294 	while (vm->vm_nfreetags <= BT_MINRESERVE && (flags & VM_POPULATING) == 0) {
295 		VMEM_UNLOCK(vm);
296 		if (bt_refill(vm)) {
297 			if ((flags & VM_NOSLEEP) != 0) {
298 				return NULL;
299 			}
300 
301 			/*
302 			 * It would be nice to wait for something specific here
303 			 * but there are multiple ways that a retry could
304 			 * succeed and we can't wait for multiple things
305 			 * simultaneously.  So we'll just sleep for an arbitrary
306 			 * short period of time and retry regardless.
307 			 * This should be a very rare case.
308 			 */
309 
310 			vmem_kick_pdaemon();
311 			kpause("btalloc", false, 1, NULL);
312 		}
313 		VMEM_LOCK(vm);
314 	}
315 	bt = LIST_FIRST(&vm->vm_freetags);
316 	LIST_REMOVE(bt, bt_freelist);
317 	vm->vm_nfreetags--;
318 	VMEM_UNLOCK(vm);
319 
320 	return bt;
321 }
322 
323 static void
324 bt_free(vmem_t *vm, bt_t *bt)
325 {
326 
327 	VMEM_LOCK(vm);
328 	LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
329 	vm->vm_nfreetags++;
330 	VMEM_UNLOCK(vm);
331 }
332 
333 static void
334 bt_freetrim(vmem_t *vm, int freelimit)
335 {
336 	bt_t *t;
337 	LIST_HEAD(, vmem_btag) tofree;
338 
339 	LIST_INIT(&tofree);
340 
341 	VMEM_LOCK(vm);
342 	while (vm->vm_nfreetags > freelimit) {
343 		bt_t *bt = LIST_FIRST(&vm->vm_freetags);
344 		LIST_REMOVE(bt, bt_freelist);
345 		vm->vm_nfreetags--;
346 		if (bt >= static_bts
347 		    && bt < &static_bts[STATIC_BT_COUNT]) {
348 			mutex_enter(&vmem_btag_lock);
349 			LIST_INSERT_HEAD(&vmem_btag_freelist, bt, bt_freelist);
350 			vmem_btag_freelist_count++;
351 			mutex_exit(&vmem_btag_lock);
352 			VMEM_EVCNT_DECR(static_bt_inuse);
353 		} else {
354 			LIST_INSERT_HEAD(&tofree, bt, bt_freelist);
355 		}
356 	}
357 
358 	VMEM_UNLOCK(vm);
359 	while (!LIST_EMPTY(&tofree)) {
360 		t = LIST_FIRST(&tofree);
361 		LIST_REMOVE(t, bt_freelist);
362 		pool_put(&vmem_btag_pool, t);
363 	}
364 }
365 #endif	/* defined(_KERNEL) */
366 
367 /*
368  * freelist[0] ... [1, 1]
369  * freelist[1] ... [2, 3]
370  * freelist[2] ... [4, 7]
371  * freelist[3] ... [8, 15]
372  *  :
373  * freelist[n] ... [(1 << n), (1 << (n + 1)) - 1]
374  *  :
375  */
376 
377 static struct vmem_freelist *
378 bt_freehead_tofree(vmem_t *vm, vmem_size_t size)
379 {
380 	const vmem_size_t qsize = size >> vm->vm_quantum_shift;
381 	const int idx = SIZE2ORDER(qsize);
382 
383 	KASSERT(size != 0 && qsize != 0);
384 	KASSERT((size & vm->vm_quantum_mask) == 0);
385 	KASSERT(idx >= 0);
386 	KASSERT(idx < VMEM_MAXORDER);
387 
388 	return &vm->vm_freelist[idx];
389 }
390 
391 /*
392  * bt_freehead_toalloc: return the freelist for the given size and allocation
393  * strategy.
394  *
395  * for VM_INSTANTFIT, return the list in which any blocks are large enough
396  * for the requested size.  otherwise, return the list which can have blocks
397  * large enough for the requested size.
398  */
399 
400 static struct vmem_freelist *
401 bt_freehead_toalloc(vmem_t *vm, vmem_size_t size, vm_flag_t strat)
402 {
403 	const vmem_size_t qsize = size >> vm->vm_quantum_shift;
404 	int idx = SIZE2ORDER(qsize);
405 
406 	KASSERT(size != 0 && qsize != 0);
407 	KASSERT((size & vm->vm_quantum_mask) == 0);
408 
409 	if (strat == VM_INSTANTFIT && ORDER2SIZE(idx) != qsize) {
410 		idx++;
411 		/* check too large request? */
412 	}
413 	KASSERT(idx >= 0);
414 	KASSERT(idx < VMEM_MAXORDER);
415 
416 	return &vm->vm_freelist[idx];
417 }
418 
419 /* ---- boundary tag hash */
420 
421 static struct vmem_hashlist *
422 bt_hashhead(vmem_t *vm, vmem_addr_t addr)
423 {
424 	struct vmem_hashlist *list;
425 	unsigned int hash;
426 
427 	hash = hash32_buf(&addr, sizeof(addr), HASH32_BUF_INIT);
428 	list = &vm->vm_hashlist[hash % vm->vm_hashsize];
429 
430 	return list;
431 }
432 
433 static bt_t *
434 bt_lookupbusy(vmem_t *vm, vmem_addr_t addr)
435 {
436 	struct vmem_hashlist *list;
437 	bt_t *bt;
438 
439 	list = bt_hashhead(vm, addr);
440 	LIST_FOREACH(bt, list, bt_hashlist) {
441 		if (bt->bt_start == addr) {
442 			break;
443 		}
444 	}
445 
446 	return bt;
447 }
448 
449 static void
450 bt_rembusy(vmem_t *vm, bt_t *bt)
451 {
452 
453 	KASSERT(vm->vm_nbusytag > 0);
454 	vm->vm_inuse -= bt->bt_size;
455 	vm->vm_nbusytag--;
456 	LIST_REMOVE(bt, bt_hashlist);
457 }
458 
459 static void
460 bt_insbusy(vmem_t *vm, bt_t *bt)
461 {
462 	struct vmem_hashlist *list;
463 
464 	KASSERT(bt->bt_type == BT_TYPE_BUSY);
465 
466 	list = bt_hashhead(vm, bt->bt_start);
467 	LIST_INSERT_HEAD(list, bt, bt_hashlist);
468 	vm->vm_nbusytag++;
469 	vm->vm_inuse += bt->bt_size;
470 }
471 
472 /* ---- boundary tag list */
473 
474 static void
475 bt_remseg(vmem_t *vm, bt_t *bt)
476 {
477 
478 	TAILQ_REMOVE(&vm->vm_seglist, bt, bt_seglist);
479 }
480 
481 static void
482 bt_insseg(vmem_t *vm, bt_t *bt, bt_t *prev)
483 {
484 
485 	TAILQ_INSERT_AFTER(&vm->vm_seglist, prev, bt, bt_seglist);
486 }
487 
488 static void
489 bt_insseg_tail(vmem_t *vm, bt_t *bt)
490 {
491 
492 	TAILQ_INSERT_TAIL(&vm->vm_seglist, bt, bt_seglist);
493 }
494 
495 static void
496 bt_remfree(vmem_t *vm, bt_t *bt)
497 {
498 
499 	KASSERT(bt->bt_type == BT_TYPE_FREE);
500 
501 	LIST_REMOVE(bt, bt_freelist);
502 }
503 
504 static void
505 bt_insfree(vmem_t *vm, bt_t *bt)
506 {
507 	struct vmem_freelist *list;
508 
509 	list = bt_freehead_tofree(vm, bt->bt_size);
510 	LIST_INSERT_HEAD(list, bt, bt_freelist);
511 }
512 
513 /* ---- vmem internal functions */
514 
515 #if defined(QCACHE)
516 static inline vm_flag_t
517 prf_to_vmf(int prflags)
518 {
519 	vm_flag_t vmflags;
520 
521 	KASSERT((prflags & ~(PR_LIMITFAIL | PR_WAITOK | PR_NOWAIT)) == 0);
522 	if ((prflags & PR_WAITOK) != 0) {
523 		vmflags = VM_SLEEP;
524 	} else {
525 		vmflags = VM_NOSLEEP;
526 	}
527 	return vmflags;
528 }
529 
530 static inline int
531 vmf_to_prf(vm_flag_t vmflags)
532 {
533 	int prflags;
534 
535 	if ((vmflags & VM_SLEEP) != 0) {
536 		prflags = PR_WAITOK;
537 	} else {
538 		prflags = PR_NOWAIT;
539 	}
540 	return prflags;
541 }
542 
543 static size_t
544 qc_poolpage_size(size_t qcache_max)
545 {
546 	int i;
547 
548 	for (i = 0; ORDER2SIZE(i) <= qcache_max * 3; i++) {
549 		/* nothing */
550 	}
551 	return ORDER2SIZE(i);
552 }
553 
554 static void *
555 qc_poolpage_alloc(struct pool *pool, int prflags)
556 {
557 	qcache_t *qc = QC_POOL_TO_QCACHE(pool);
558 	vmem_t *vm = qc->qc_vmem;
559 	vmem_addr_t addr;
560 
561 	if (vmem_alloc(vm, pool->pr_alloc->pa_pagesz,
562 	    prf_to_vmf(prflags) | VM_INSTANTFIT, &addr) != 0)
563 		return NULL;
564 	return (void *)addr;
565 }
566 
567 static void
568 qc_poolpage_free(struct pool *pool, void *addr)
569 {
570 	qcache_t *qc = QC_POOL_TO_QCACHE(pool);
571 	vmem_t *vm = qc->qc_vmem;
572 
573 	vmem_free(vm, (vmem_addr_t)addr, pool->pr_alloc->pa_pagesz);
574 }
575 
576 static void
577 qc_init(vmem_t *vm, size_t qcache_max, int ipl)
578 {
579 	qcache_t *prevqc;
580 	struct pool_allocator *pa;
581 	int qcache_idx_max;
582 	int i;
583 
584 	KASSERT((qcache_max & vm->vm_quantum_mask) == 0);
585 	if (qcache_max > (VMEM_QCACHE_IDX_MAX << vm->vm_quantum_shift)) {
586 		qcache_max = VMEM_QCACHE_IDX_MAX << vm->vm_quantum_shift;
587 	}
588 	vm->vm_qcache_max = qcache_max;
589 	pa = &vm->vm_qcache_allocator;
590 	memset(pa, 0, sizeof(*pa));
591 	pa->pa_alloc = qc_poolpage_alloc;
592 	pa->pa_free = qc_poolpage_free;
593 	pa->pa_pagesz = qc_poolpage_size(qcache_max);
594 
595 	qcache_idx_max = qcache_max >> vm->vm_quantum_shift;
596 	prevqc = NULL;
597 	for (i = qcache_idx_max; i > 0; i--) {
598 		qcache_t *qc = &vm->vm_qcache_store[i - 1];
599 		size_t size = i << vm->vm_quantum_shift;
600 		pool_cache_t pc;
601 
602 		qc->qc_vmem = vm;
603 		snprintf(qc->qc_name, sizeof(qc->qc_name), "%s-%zu",
604 		    vm->vm_name, size);
605 
606 		pc = pool_cache_init(size,
607 		    ORDER2SIZE(vm->vm_quantum_shift), 0,
608 		    PR_NOALIGN | PR_NOTOUCH | PR_RECURSIVE /* XXX */,
609 		    qc->qc_name, pa, ipl, NULL, NULL, NULL);
610 
611 		KASSERT(pc);
612 
613 		qc->qc_cache = pc;
614 		KASSERT(qc->qc_cache != NULL);	/* XXX */
615 		if (prevqc != NULL &&
616 		    qc->qc_cache->pc_pool.pr_itemsperpage ==
617 		    prevqc->qc_cache->pc_pool.pr_itemsperpage) {
618 			pool_cache_destroy(qc->qc_cache);
619 			vm->vm_qcache[i - 1] = prevqc;
620 			continue;
621 		}
622 		qc->qc_cache->pc_pool.pr_qcache = qc;
623 		vm->vm_qcache[i - 1] = qc;
624 		prevqc = qc;
625 	}
626 }
627 
628 static void
629 qc_destroy(vmem_t *vm)
630 {
631 	const qcache_t *prevqc;
632 	int i;
633 	int qcache_idx_max;
634 
635 	qcache_idx_max = vm->vm_qcache_max >> vm->vm_quantum_shift;
636 	prevqc = NULL;
637 	for (i = 0; i < qcache_idx_max; i++) {
638 		qcache_t *qc = vm->vm_qcache[i];
639 
640 		if (prevqc == qc) {
641 			continue;
642 		}
643 		pool_cache_destroy(qc->qc_cache);
644 		prevqc = qc;
645 	}
646 }
647 #endif
648 
649 #if defined(_KERNEL)
650 static void
651 vmem_bootstrap(void)
652 {
653 
654 	mutex_init(&vmem_list_lock, MUTEX_DEFAULT, IPL_VM);
655 	mutex_init(&vmem_btag_lock, MUTEX_DEFAULT, IPL_VM);
656 	mutex_init(&vmem_btag_refill_lock, MUTEX_DEFAULT, IPL_VM);
657 
658 	while (static_bt_count-- > 0) {
659 		bt_t *bt = &static_bts[static_bt_count];
660 		LIST_INSERT_HEAD(&vmem_btag_freelist, bt, bt_freelist);
661 		VMEM_EVCNT_INCR(static_bt_count);
662 		vmem_btag_freelist_count++;
663 	}
664 	vmem_bootstrapped = TRUE;
665 }
666 
667 void
668 vmem_subsystem_init(vmem_t *vm)
669 {
670 
671 	kmem_va_meta_arena = vmem_init(&kmem_va_meta_arena_store, "vmem-va",
672 	    0, 0, PAGE_SIZE, vmem_alloc, vmem_free, vm,
673 	    0, VM_NOSLEEP | VM_BOOTSTRAP | VM_LARGEIMPORT,
674 	    IPL_VM);
675 
676 	kmem_meta_arena = vmem_init(&kmem_meta_arena_store, "vmem-meta",
677 	    0, 0, PAGE_SIZE,
678 	    uvm_km_kmem_alloc, uvm_km_kmem_free, kmem_va_meta_arena,
679 	    0, VM_NOSLEEP | VM_BOOTSTRAP, IPL_VM);
680 
681 	pool_init(&vmem_btag_pool, sizeof(bt_t), 0, 0, PR_PHINPAGE,
682 		    "vmembt", &pool_allocator_vmem_meta, IPL_VM);
683 }
684 #endif /* defined(_KERNEL) */
685 
686 static int
687 vmem_add1(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, vm_flag_t flags,
688     int spanbttype)
689 {
690 	bt_t *btspan;
691 	bt_t *btfree;
692 
693 	KASSERT((flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
694 	KASSERT((~flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
695 	KASSERT(spanbttype == BT_TYPE_SPAN ||
696 	    spanbttype == BT_TYPE_SPAN_STATIC);
697 
698 	btspan = bt_alloc(vm, flags);
699 	if (btspan == NULL) {
700 		return ENOMEM;
701 	}
702 	btfree = bt_alloc(vm, flags);
703 	if (btfree == NULL) {
704 		bt_free(vm, btspan);
705 		return ENOMEM;
706 	}
707 
708 	btspan->bt_type = spanbttype;
709 	btspan->bt_start = addr;
710 	btspan->bt_size = size;
711 
712 	btfree->bt_type = BT_TYPE_FREE;
713 	btfree->bt_start = addr;
714 	btfree->bt_size = size;
715 
716 	VMEM_LOCK(vm);
717 	bt_insseg_tail(vm, btspan);
718 	bt_insseg(vm, btfree, btspan);
719 	bt_insfree(vm, btfree);
720 	vm->vm_size += size;
721 	VMEM_UNLOCK(vm);
722 
723 	return 0;
724 }
725 
726 static void
727 vmem_destroy1(vmem_t *vm)
728 {
729 
730 #if defined(QCACHE)
731 	qc_destroy(vm);
732 #endif /* defined(QCACHE) */
733 	if (vm->vm_hashlist != NULL) {
734 		int i;
735 
736 		for (i = 0; i < vm->vm_hashsize; i++) {
737 			bt_t *bt;
738 
739 			while ((bt = LIST_FIRST(&vm->vm_hashlist[i])) != NULL) {
740 				KASSERT(bt->bt_type == BT_TYPE_SPAN_STATIC);
741 				bt_free(vm, bt);
742 			}
743 		}
744 		if (vm->vm_hashlist != &vm->vm_hash0) {
745 			xfree(vm->vm_hashlist,
746 			    sizeof(struct vmem_hashlist *) * vm->vm_hashsize);
747 		}
748 	}
749 
750 	bt_freetrim(vm, 0);
751 
752 	VMEM_CONDVAR_DESTROY(vm);
753 	VMEM_LOCK_DESTROY(vm);
754 	xfree(vm, sizeof(*vm));
755 }
756 
757 static int
758 vmem_import(vmem_t *vm, vmem_size_t size, vm_flag_t flags)
759 {
760 	vmem_addr_t addr;
761 	int rc;
762 
763 	if (vm->vm_importfn == NULL) {
764 		return EINVAL;
765 	}
766 
767 	if (vm->vm_flags & VM_LARGEIMPORT) {
768 		size *= 16;
769 	}
770 
771 	if (vm->vm_flags & VM_XIMPORT) {
772 		rc = ((vmem_ximport_t *)vm->vm_importfn)(vm->vm_arg, size,
773 		    &size, flags, &addr);
774 	} else {
775 		rc = (vm->vm_importfn)(vm->vm_arg, size, flags, &addr);
776 	}
777 	if (rc) {
778 		return ENOMEM;
779 	}
780 
781 	if (vmem_add1(vm, addr, size, flags, BT_TYPE_SPAN) != 0) {
782 		(*vm->vm_releasefn)(vm->vm_arg, addr, size);
783 		return ENOMEM;
784 	}
785 
786 	return 0;
787 }
788 
789 static int
790 vmem_rehash(vmem_t *vm, size_t newhashsize, vm_flag_t flags)
791 {
792 	bt_t *bt;
793 	int i;
794 	struct vmem_hashlist *newhashlist;
795 	struct vmem_hashlist *oldhashlist;
796 	size_t oldhashsize;
797 
798 	KASSERT(newhashsize > 0);
799 
800 	newhashlist =
801 	    xmalloc(sizeof(struct vmem_hashlist *) * newhashsize, flags);
802 	if (newhashlist == NULL) {
803 		return ENOMEM;
804 	}
805 	for (i = 0; i < newhashsize; i++) {
806 		LIST_INIT(&newhashlist[i]);
807 	}
808 
809 	if (!VMEM_TRYLOCK(vm)) {
810 		xfree(newhashlist,
811 		    sizeof(struct vmem_hashlist *) * newhashsize);
812 		return EBUSY;
813 	}
814 	oldhashlist = vm->vm_hashlist;
815 	oldhashsize = vm->vm_hashsize;
816 	vm->vm_hashlist = newhashlist;
817 	vm->vm_hashsize = newhashsize;
818 	if (oldhashlist == NULL) {
819 		VMEM_UNLOCK(vm);
820 		return 0;
821 	}
822 	for (i = 0; i < oldhashsize; i++) {
823 		while ((bt = LIST_FIRST(&oldhashlist[i])) != NULL) {
824 			bt_rembusy(vm, bt); /* XXX */
825 			bt_insbusy(vm, bt);
826 		}
827 	}
828 	VMEM_UNLOCK(vm);
829 
830 	if (oldhashlist != &vm->vm_hash0) {
831 		xfree(oldhashlist,
832 		    sizeof(struct vmem_hashlist *) * oldhashsize);
833 	}
834 
835 	return 0;
836 }
837 
838 /*
839  * vmem_fit: check if a bt can satisfy the given restrictions.
840  *
841  * it's a caller's responsibility to ensure the region is big enough
842  * before calling us.
843  */
844 
845 static int
846 vmem_fit(const bt_t *bt, vmem_size_t size, vmem_size_t align,
847     vmem_size_t phase, vmem_size_t nocross,
848     vmem_addr_t minaddr, vmem_addr_t maxaddr, vmem_addr_t *addrp)
849 {
850 	vmem_addr_t start;
851 	vmem_addr_t end;
852 
853 	KASSERT(size > 0);
854 	KASSERT(bt->bt_size >= size); /* caller's responsibility */
855 
856 	/*
857 	 * XXX assumption: vmem_addr_t and vmem_size_t are
858 	 * unsigned integer of the same size.
859 	 */
860 
861 	start = bt->bt_start;
862 	if (start < minaddr) {
863 		start = minaddr;
864 	}
865 	end = BT_END(bt);
866 	if (end > maxaddr) {
867 		end = maxaddr;
868 	}
869 	if (start > end) {
870 		return ENOMEM;
871 	}
872 
873 	start = VMEM_ALIGNUP(start - phase, align) + phase;
874 	if (start < bt->bt_start) {
875 		start += align;
876 	}
877 	if (VMEM_CROSS_P(start, start + size - 1, nocross)) {
878 		KASSERT(align < nocross);
879 		start = VMEM_ALIGNUP(start - phase, nocross) + phase;
880 	}
881 	if (start <= end && end - start >= size - 1) {
882 		KASSERT((start & (align - 1)) == phase);
883 		KASSERT(!VMEM_CROSS_P(start, start + size - 1, nocross));
884 		KASSERT(minaddr <= start);
885 		KASSERT(maxaddr == 0 || start + size - 1 <= maxaddr);
886 		KASSERT(bt->bt_start <= start);
887 		KASSERT(BT_END(bt) - start >= size - 1);
888 		*addrp = start;
889 		return 0;
890 	}
891 	return ENOMEM;
892 }
893 
894 /* ---- vmem API */
895 
896 /*
897  * vmem_create_internal: creates a vmem arena.
898  */
899 
900 vmem_t *
901 vmem_init(vmem_t *vm, const char *name,
902     vmem_addr_t base, vmem_size_t size, vmem_size_t quantum,
903     vmem_import_t *importfn, vmem_release_t *releasefn,
904     vmem_t *arg, vmem_size_t qcache_max, vm_flag_t flags, int ipl)
905 {
906 	int i;
907 
908 	KASSERT((flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
909 	KASSERT((~flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
910 	KASSERT(quantum > 0);
911 
912 #if defined(_KERNEL)
913 	/* XXX: SMP, we get called early... */
914 	if (!vmem_bootstrapped) {
915 		vmem_bootstrap();
916 	}
917 #endif /* defined(_KERNEL) */
918 
919 	if (vm == NULL) {
920 		vm = xmalloc(sizeof(*vm), flags);
921 	}
922 	if (vm == NULL) {
923 		return NULL;
924 	}
925 
926 	VMEM_CONDVAR_INIT(vm, "vmem");
927 	VMEM_LOCK_INIT(vm, ipl);
928 	vm->vm_flags = flags;
929 	vm->vm_nfreetags = 0;
930 	LIST_INIT(&vm->vm_freetags);
931 	strlcpy(vm->vm_name, name, sizeof(vm->vm_name));
932 	vm->vm_quantum_mask = quantum - 1;
933 	vm->vm_quantum_shift = SIZE2ORDER(quantum);
934 	KASSERT(ORDER2SIZE(vm->vm_quantum_shift) == quantum);
935 	vm->vm_importfn = importfn;
936 	vm->vm_releasefn = releasefn;
937 	vm->vm_arg = arg;
938 	vm->vm_nbusytag = 0;
939 	vm->vm_size = 0;
940 	vm->vm_inuse = 0;
941 #if defined(QCACHE)
942 	qc_init(vm, qcache_max, ipl);
943 #endif /* defined(QCACHE) */
944 
945 	TAILQ_INIT(&vm->vm_seglist);
946 	for (i = 0; i < VMEM_MAXORDER; i++) {
947 		LIST_INIT(&vm->vm_freelist[i]);
948 	}
949 	memset(&vm->vm_hash0, 0, sizeof(struct vmem_hashlist));
950 	vm->vm_hashsize = 1;
951 	vm->vm_hashlist = &vm->vm_hash0;
952 
953 	if (size != 0) {
954 		if (vmem_add(vm, base, size, flags) != 0) {
955 			vmem_destroy1(vm);
956 			return NULL;
957 		}
958 	}
959 
960 #if defined(_KERNEL)
961 	if (flags & VM_BOOTSTRAP) {
962 		bt_refill(vm);
963 	}
964 
965 	mutex_enter(&vmem_list_lock);
966 	LIST_INSERT_HEAD(&vmem_list, vm, vm_alllist);
967 	mutex_exit(&vmem_list_lock);
968 #endif /* defined(_KERNEL) */
969 
970 	return vm;
971 }
972 
973 
974 
975 /*
976  * vmem_create: create an arena.
977  *
978  * => must not be called from interrupt context.
979  */
980 
981 vmem_t *
982 vmem_create(const char *name, vmem_addr_t base, vmem_size_t size,
983     vmem_size_t quantum, vmem_import_t *importfn, vmem_release_t *releasefn,
984     vmem_t *source, vmem_size_t qcache_max, vm_flag_t flags, int ipl)
985 {
986 
987 	KASSERT((flags & (VM_XIMPORT)) == 0);
988 
989 	return vmem_init(NULL, name, base, size, quantum,
990 	    importfn, releasefn, source, qcache_max, flags, ipl);
991 }
992 
993 /*
994  * vmem_xcreate: create an arena takes alternative import func.
995  *
996  * => must not be called from interrupt context.
997  */
998 
999 vmem_t *
1000 vmem_xcreate(const char *name, vmem_addr_t base, vmem_size_t size,
1001     vmem_size_t quantum, vmem_ximport_t *importfn, vmem_release_t *releasefn,
1002     vmem_t *source, vmem_size_t qcache_max, vm_flag_t flags, int ipl)
1003 {
1004 
1005 	KASSERT((flags & (VM_XIMPORT)) == 0);
1006 
1007 	return vmem_init(NULL, name, base, size, quantum,
1008 	    (vmem_import_t *)importfn, releasefn, source,
1009 	    qcache_max, flags | VM_XIMPORT, ipl);
1010 }
1011 
1012 void
1013 vmem_destroy(vmem_t *vm)
1014 {
1015 
1016 #if defined(_KERNEL)
1017 	mutex_enter(&vmem_list_lock);
1018 	LIST_REMOVE(vm, vm_alllist);
1019 	mutex_exit(&vmem_list_lock);
1020 #endif /* defined(_KERNEL) */
1021 
1022 	vmem_destroy1(vm);
1023 }
1024 
1025 vmem_size_t
1026 vmem_roundup_size(vmem_t *vm, vmem_size_t size)
1027 {
1028 
1029 	return (size + vm->vm_quantum_mask) & ~vm->vm_quantum_mask;
1030 }
1031 
1032 /*
1033  * vmem_alloc: allocate resource from the arena.
1034  */
1035 
1036 int
1037 vmem_alloc(vmem_t *vm, vmem_size_t size, vm_flag_t flags, vmem_addr_t *addrp)
1038 {
1039 	const vm_flag_t strat __diagused = flags & VM_FITMASK;
1040 	int error;
1041 
1042 	KASSERT((flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
1043 	KASSERT((~flags & (VM_SLEEP|VM_NOSLEEP)) != 0);
1044 
1045 	KASSERT(size > 0);
1046 	KASSERT(strat == VM_BESTFIT || strat == VM_INSTANTFIT);
1047 	if ((flags & VM_SLEEP) != 0) {
1048 		ASSERT_SLEEPABLE();
1049 	}
1050 
1051 #if defined(QCACHE)
1052 	if (size <= vm->vm_qcache_max) {
1053 		void *p;
1054 		int qidx = (size + vm->vm_quantum_mask) >> vm->vm_quantum_shift;
1055 		qcache_t *qc = vm->vm_qcache[qidx - 1];
1056 
1057 		p = pool_cache_get(qc->qc_cache, vmf_to_prf(flags));
1058 		if (addrp != NULL)
1059 			*addrp = (vmem_addr_t)p;
1060 		error = (p == NULL) ? ENOMEM : 0;
1061 		goto out;
1062 	}
1063 #endif /* defined(QCACHE) */
1064 
1065 	error = vmem_xalloc(vm, size, 0, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX,
1066 	    flags, addrp);
1067 out:
1068 	KASSERT(error == 0 || (flags & VM_SLEEP) == 0);
1069 	return error;
1070 }
1071 
1072 int
1073 vmem_xalloc(vmem_t *vm, const vmem_size_t size0, vmem_size_t align,
1074     const vmem_size_t phase, const vmem_size_t nocross,
1075     const vmem_addr_t minaddr, const vmem_addr_t maxaddr, const vm_flag_t flags,
1076     vmem_addr_t *addrp)
1077 {
1078 	struct vmem_freelist *list;
1079 	struct vmem_freelist *first;
1080 	struct vmem_freelist *end;
1081 	bt_t *bt;
1082 	bt_t *btnew;
1083 	bt_t *btnew2;
1084 	const vmem_size_t size = vmem_roundup_size(vm, size0);
1085 	vm_flag_t strat = flags & VM_FITMASK;
1086 	vmem_addr_t start;
1087 	int rc;
1088 
1089 	KASSERT(size0 > 0);
1090 	KASSERT(size > 0);
1091 	KASSERT(strat == VM_BESTFIT || strat == VM_INSTANTFIT);
1092 	if ((flags & VM_SLEEP) != 0) {
1093 		ASSERT_SLEEPABLE();
1094 	}
1095 	KASSERT((align & vm->vm_quantum_mask) == 0);
1096 	KASSERT((align & (align - 1)) == 0);
1097 	KASSERT((phase & vm->vm_quantum_mask) == 0);
1098 	KASSERT((nocross & vm->vm_quantum_mask) == 0);
1099 	KASSERT((nocross & (nocross - 1)) == 0);
1100 	KASSERT((align == 0 && phase == 0) || phase < align);
1101 	KASSERT(nocross == 0 || nocross >= size);
1102 	KASSERT(minaddr <= maxaddr);
1103 	KASSERT(!VMEM_CROSS_P(phase, phase + size - 1, nocross));
1104 
1105 	if (align == 0) {
1106 		align = vm->vm_quantum_mask + 1;
1107 	}
1108 
1109 	/*
1110 	 * allocate boundary tags before acquiring the vmem lock.
1111 	 */
1112 	btnew = bt_alloc(vm, flags);
1113 	if (btnew == NULL) {
1114 		return ENOMEM;
1115 	}
1116 	btnew2 = bt_alloc(vm, flags); /* XXX not necessary if no restrictions */
1117 	if (btnew2 == NULL) {
1118 		bt_free(vm, btnew);
1119 		return ENOMEM;
1120 	}
1121 
1122 	/*
1123 	 * choose a free block from which we allocate.
1124 	 */
1125 retry_strat:
1126 	first = bt_freehead_toalloc(vm, size, strat);
1127 	end = &vm->vm_freelist[VMEM_MAXORDER];
1128 retry:
1129 	bt = NULL;
1130 	VMEM_LOCK(vm);
1131 	vmem_check(vm);
1132 	if (strat == VM_INSTANTFIT) {
1133 		/*
1134 		 * just choose the first block which satisfies our restrictions.
1135 		 *
1136 		 * note that we don't need to check the size of the blocks
1137 		 * because any blocks found on these list should be larger than
1138 		 * the given size.
1139 		 */
1140 		for (list = first; list < end; list++) {
1141 			bt = LIST_FIRST(list);
1142 			if (bt != NULL) {
1143 				rc = vmem_fit(bt, size, align, phase,
1144 				    nocross, minaddr, maxaddr, &start);
1145 				if (rc == 0) {
1146 					goto gotit;
1147 				}
1148 				/*
1149 				 * don't bother to follow the bt_freelist link
1150 				 * here.  the list can be very long and we are
1151 				 * told to run fast.  blocks from the later free
1152 				 * lists are larger and have better chances to
1153 				 * satisfy our restrictions.
1154 				 */
1155 			}
1156 		}
1157 	} else { /* VM_BESTFIT */
1158 		/*
1159 		 * we assume that, for space efficiency, it's better to
1160 		 * allocate from a smaller block.  thus we will start searching
1161 		 * from the lower-order list than VM_INSTANTFIT.
1162 		 * however, don't bother to find the smallest block in a free
1163 		 * list because the list can be very long.  we can revisit it
1164 		 * if/when it turns out to be a problem.
1165 		 *
1166 		 * note that the 'first' list can contain blocks smaller than
1167 		 * the requested size.  thus we need to check bt_size.
1168 		 */
1169 		for (list = first; list < end; list++) {
1170 			LIST_FOREACH(bt, list, bt_freelist) {
1171 				if (bt->bt_size >= size) {
1172 					rc = vmem_fit(bt, size, align, phase,
1173 					    nocross, minaddr, maxaddr, &start);
1174 					if (rc == 0) {
1175 						goto gotit;
1176 					}
1177 				}
1178 			}
1179 		}
1180 	}
1181 	VMEM_UNLOCK(vm);
1182 #if 1
1183 	if (strat == VM_INSTANTFIT) {
1184 		strat = VM_BESTFIT;
1185 		goto retry_strat;
1186 	}
1187 #endif
1188 	if (align != vm->vm_quantum_mask + 1 || phase != 0 || nocross != 0) {
1189 
1190 		/*
1191 		 * XXX should try to import a region large enough to
1192 		 * satisfy restrictions?
1193 		 */
1194 
1195 		goto fail;
1196 	}
1197 	/* XXX eeek, minaddr & maxaddr not respected */
1198 	if (vmem_import(vm, size, flags) == 0) {
1199 		goto retry;
1200 	}
1201 	/* XXX */
1202 
1203 	if ((flags & VM_SLEEP) != 0) {
1204 		vmem_kick_pdaemon();
1205 		VMEM_LOCK(vm);
1206 		VMEM_CONDVAR_WAIT(vm);
1207 		VMEM_UNLOCK(vm);
1208 		goto retry;
1209 	}
1210 fail:
1211 	bt_free(vm, btnew);
1212 	bt_free(vm, btnew2);
1213 	return ENOMEM;
1214 
1215 gotit:
1216 	KASSERT(bt->bt_type == BT_TYPE_FREE);
1217 	KASSERT(bt->bt_size >= size);
1218 	bt_remfree(vm, bt);
1219 	vmem_check(vm);
1220 	if (bt->bt_start != start) {
1221 		btnew2->bt_type = BT_TYPE_FREE;
1222 		btnew2->bt_start = bt->bt_start;
1223 		btnew2->bt_size = start - bt->bt_start;
1224 		bt->bt_start = start;
1225 		bt->bt_size -= btnew2->bt_size;
1226 		bt_insfree(vm, btnew2);
1227 		bt_insseg(vm, btnew2, TAILQ_PREV(bt, vmem_seglist, bt_seglist));
1228 		btnew2 = NULL;
1229 		vmem_check(vm);
1230 	}
1231 	KASSERT(bt->bt_start == start);
1232 	if (bt->bt_size != size && bt->bt_size - size > vm->vm_quantum_mask) {
1233 		/* split */
1234 		btnew->bt_type = BT_TYPE_BUSY;
1235 		btnew->bt_start = bt->bt_start;
1236 		btnew->bt_size = size;
1237 		bt->bt_start = bt->bt_start + size;
1238 		bt->bt_size -= size;
1239 		bt_insfree(vm, bt);
1240 		bt_insseg(vm, btnew, TAILQ_PREV(bt, vmem_seglist, bt_seglist));
1241 		bt_insbusy(vm, btnew);
1242 		vmem_check(vm);
1243 		VMEM_UNLOCK(vm);
1244 	} else {
1245 		bt->bt_type = BT_TYPE_BUSY;
1246 		bt_insbusy(vm, bt);
1247 		vmem_check(vm);
1248 		VMEM_UNLOCK(vm);
1249 		bt_free(vm, btnew);
1250 		btnew = bt;
1251 	}
1252 	if (btnew2 != NULL) {
1253 		bt_free(vm, btnew2);
1254 	}
1255 	KASSERT(btnew->bt_size >= size);
1256 	btnew->bt_type = BT_TYPE_BUSY;
1257 
1258 	if (addrp != NULL)
1259 		*addrp = btnew->bt_start;
1260 	return 0;
1261 }
1262 
1263 /*
1264  * vmem_free: free the resource to the arena.
1265  */
1266 
1267 void
1268 vmem_free(vmem_t *vm, vmem_addr_t addr, vmem_size_t size)
1269 {
1270 
1271 	KASSERT(size > 0);
1272 
1273 #if defined(QCACHE)
1274 	if (size <= vm->vm_qcache_max) {
1275 		int qidx = (size + vm->vm_quantum_mask) >> vm->vm_quantum_shift;
1276 		qcache_t *qc = vm->vm_qcache[qidx - 1];
1277 
1278 		pool_cache_put(qc->qc_cache, (void *)addr);
1279 		return;
1280 	}
1281 #endif /* defined(QCACHE) */
1282 
1283 	vmem_xfree(vm, addr, size);
1284 }
1285 
1286 void
1287 vmem_xfree(vmem_t *vm, vmem_addr_t addr, vmem_size_t size)
1288 {
1289 	bt_t *bt;
1290 	bt_t *t;
1291 	LIST_HEAD(, vmem_btag) tofree;
1292 
1293 	LIST_INIT(&tofree);
1294 
1295 	KASSERT(size > 0);
1296 
1297 	VMEM_LOCK(vm);
1298 
1299 	bt = bt_lookupbusy(vm, addr);
1300 	KASSERT(bt != NULL);
1301 	KASSERT(bt->bt_start == addr);
1302 	KASSERT(bt->bt_size == vmem_roundup_size(vm, size) ||
1303 	    bt->bt_size - vmem_roundup_size(vm, size) <= vm->vm_quantum_mask);
1304 	KASSERT(bt->bt_type == BT_TYPE_BUSY);
1305 	bt_rembusy(vm, bt);
1306 	bt->bt_type = BT_TYPE_FREE;
1307 
1308 	/* coalesce */
1309 	t = TAILQ_NEXT(bt, bt_seglist);
1310 	if (t != NULL && t->bt_type == BT_TYPE_FREE) {
1311 		KASSERT(BT_END(bt) < t->bt_start);	/* YYY */
1312 		bt_remfree(vm, t);
1313 		bt_remseg(vm, t);
1314 		bt->bt_size += t->bt_size;
1315 		LIST_INSERT_HEAD(&tofree, t, bt_freelist);
1316 	}
1317 	t = TAILQ_PREV(bt, vmem_seglist, bt_seglist);
1318 	if (t != NULL && t->bt_type == BT_TYPE_FREE) {
1319 		KASSERT(BT_END(t) < bt->bt_start);	/* YYY */
1320 		bt_remfree(vm, t);
1321 		bt_remseg(vm, t);
1322 		bt->bt_size += t->bt_size;
1323 		bt->bt_start = t->bt_start;
1324 		LIST_INSERT_HEAD(&tofree, t, bt_freelist);
1325 	}
1326 
1327 	t = TAILQ_PREV(bt, vmem_seglist, bt_seglist);
1328 	KASSERT(t != NULL);
1329 	KASSERT(BT_ISSPAN_P(t) || t->bt_type == BT_TYPE_BUSY);
1330 	if (vm->vm_releasefn != NULL && t->bt_type == BT_TYPE_SPAN &&
1331 	    t->bt_size == bt->bt_size) {
1332 		vmem_addr_t spanaddr;
1333 		vmem_size_t spansize;
1334 
1335 		KASSERT(t->bt_start == bt->bt_start);
1336 		spanaddr = bt->bt_start;
1337 		spansize = bt->bt_size;
1338 		bt_remseg(vm, bt);
1339 		LIST_INSERT_HEAD(&tofree, bt, bt_freelist);
1340 		bt_remseg(vm, t);
1341 		LIST_INSERT_HEAD(&tofree, t, bt_freelist);
1342 		vm->vm_size -= spansize;
1343 		VMEM_CONDVAR_BROADCAST(vm);
1344 		VMEM_UNLOCK(vm);
1345 		(*vm->vm_releasefn)(vm->vm_arg, spanaddr, spansize);
1346 	} else {
1347 		bt_insfree(vm, bt);
1348 		VMEM_CONDVAR_BROADCAST(vm);
1349 		VMEM_UNLOCK(vm);
1350 	}
1351 
1352 	while (!LIST_EMPTY(&tofree)) {
1353 		t = LIST_FIRST(&tofree);
1354 		LIST_REMOVE(t, bt_freelist);
1355 		bt_free(vm, t);
1356 	}
1357 
1358 	bt_freetrim(vm, BT_MAXFREE);
1359 }
1360 
1361 /*
1362  * vmem_add:
1363  *
1364  * => caller must ensure appropriate spl,
1365  *    if the arena can be accessed from interrupt context.
1366  */
1367 
1368 int
1369 vmem_add(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, vm_flag_t flags)
1370 {
1371 
1372 	return vmem_add1(vm, addr, size, flags, BT_TYPE_SPAN_STATIC);
1373 }
1374 
1375 /*
1376  * vmem_size: information about arenas size
1377  *
1378  * => return free/allocated size in arena
1379  */
1380 vmem_size_t
1381 vmem_size(vmem_t *vm, int typemask)
1382 {
1383 
1384 	switch (typemask) {
1385 	case VMEM_ALLOC:
1386 		return vm->vm_inuse;
1387 	case VMEM_FREE:
1388 		return vm->vm_size - vm->vm_inuse;
1389 	case VMEM_FREE|VMEM_ALLOC:
1390 		return vm->vm_size;
1391 	default:
1392 		panic("vmem_size");
1393 	}
1394 }
1395 
1396 /* ---- rehash */
1397 
1398 #if defined(_KERNEL)
1399 static struct callout vmem_rehash_ch;
1400 static int vmem_rehash_interval;
1401 static struct workqueue *vmem_rehash_wq;
1402 static struct work vmem_rehash_wk;
1403 
1404 static void
1405 vmem_rehash_all(struct work *wk, void *dummy)
1406 {
1407 	vmem_t *vm;
1408 
1409 	KASSERT(wk == &vmem_rehash_wk);
1410 	mutex_enter(&vmem_list_lock);
1411 	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1412 		size_t desired;
1413 		size_t current;
1414 
1415 		if (!VMEM_TRYLOCK(vm)) {
1416 			continue;
1417 		}
1418 		desired = vm->vm_nbusytag;
1419 		current = vm->vm_hashsize;
1420 		VMEM_UNLOCK(vm);
1421 
1422 		if (desired > VMEM_HASHSIZE_MAX) {
1423 			desired = VMEM_HASHSIZE_MAX;
1424 		} else if (desired < VMEM_HASHSIZE_MIN) {
1425 			desired = VMEM_HASHSIZE_MIN;
1426 		}
1427 		if (desired > current * 2 || desired * 2 < current) {
1428 			vmem_rehash(vm, desired, VM_NOSLEEP);
1429 		}
1430 	}
1431 	mutex_exit(&vmem_list_lock);
1432 
1433 	callout_schedule(&vmem_rehash_ch, vmem_rehash_interval);
1434 }
1435 
1436 static void
1437 vmem_rehash_all_kick(void *dummy)
1438 {
1439 
1440 	workqueue_enqueue(vmem_rehash_wq, &vmem_rehash_wk, NULL);
1441 }
1442 
1443 void
1444 vmem_rehash_start(void)
1445 {
1446 	int error;
1447 
1448 	error = workqueue_create(&vmem_rehash_wq, "vmem_rehash",
1449 	    vmem_rehash_all, NULL, PRI_VM, IPL_SOFTCLOCK, WQ_MPSAFE);
1450 	if (error) {
1451 		panic("%s: workqueue_create %d\n", __func__, error);
1452 	}
1453 	callout_init(&vmem_rehash_ch, CALLOUT_MPSAFE);
1454 	callout_setfunc(&vmem_rehash_ch, vmem_rehash_all_kick, NULL);
1455 
1456 	vmem_rehash_interval = hz * 10;
1457 	callout_schedule(&vmem_rehash_ch, vmem_rehash_interval);
1458 }
1459 #endif /* defined(_KERNEL) */
1460 
1461 /* ---- debug */
1462 
1463 #if defined(DDB) || defined(UNITTEST) || defined(VMEM_SANITY)
1464 
1465 static void bt_dump(const bt_t *, void (*)(const char *, ...)
1466     __printflike(1, 2));
1467 
1468 static const char *
1469 bt_type_string(int type)
1470 {
1471 	static const char * const table[] = {
1472 		[BT_TYPE_BUSY] = "busy",
1473 		[BT_TYPE_FREE] = "free",
1474 		[BT_TYPE_SPAN] = "span",
1475 		[BT_TYPE_SPAN_STATIC] = "static span",
1476 	};
1477 
1478 	if (type >= __arraycount(table)) {
1479 		return "BOGUS";
1480 	}
1481 	return table[type];
1482 }
1483 
1484 static void
1485 bt_dump(const bt_t *bt, void (*pr)(const char *, ...))
1486 {
1487 
1488 	(*pr)("\t%p: %" PRIu64 ", %" PRIu64 ", %d(%s)\n",
1489 	    bt, (uint64_t)bt->bt_start, (uint64_t)bt->bt_size,
1490 	    bt->bt_type, bt_type_string(bt->bt_type));
1491 }
1492 
1493 static void
1494 vmem_dump(const vmem_t *vm , void (*pr)(const char *, ...) __printflike(1, 2))
1495 {
1496 	const bt_t *bt;
1497 	int i;
1498 
1499 	(*pr)("vmem %p '%s'\n", vm, vm->vm_name);
1500 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1501 		bt_dump(bt, pr);
1502 	}
1503 
1504 	for (i = 0; i < VMEM_MAXORDER; i++) {
1505 		const struct vmem_freelist *fl = &vm->vm_freelist[i];
1506 
1507 		if (LIST_EMPTY(fl)) {
1508 			continue;
1509 		}
1510 
1511 		(*pr)("freelist[%d]\n", i);
1512 		LIST_FOREACH(bt, fl, bt_freelist) {
1513 			bt_dump(bt, pr);
1514 		}
1515 	}
1516 }
1517 
1518 #endif /* defined(DDB) || defined(UNITTEST) || defined(VMEM_SANITY) */
1519 
1520 #if defined(DDB)
1521 static bt_t *
1522 vmem_whatis_lookup(vmem_t *vm, uintptr_t addr)
1523 {
1524 	bt_t *bt;
1525 
1526 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1527 		if (BT_ISSPAN_P(bt)) {
1528 			continue;
1529 		}
1530 		if (bt->bt_start <= addr && addr <= BT_END(bt)) {
1531 			return bt;
1532 		}
1533 	}
1534 
1535 	return NULL;
1536 }
1537 
1538 void
1539 vmem_whatis(uintptr_t addr, void (*pr)(const char *, ...))
1540 {
1541 	vmem_t *vm;
1542 
1543 	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1544 		bt_t *bt;
1545 
1546 		bt = vmem_whatis_lookup(vm, addr);
1547 		if (bt == NULL) {
1548 			continue;
1549 		}
1550 		(*pr)("%p is %p+%zu in VMEM '%s' (%s)\n",
1551 		    (void *)addr, (void *)bt->bt_start,
1552 		    (size_t)(addr - bt->bt_start), vm->vm_name,
1553 		    (bt->bt_type == BT_TYPE_BUSY) ? "allocated" : "free");
1554 	}
1555 }
1556 
1557 void
1558 vmem_printall(const char *modif, void (*pr)(const char *, ...))
1559 {
1560 	const vmem_t *vm;
1561 
1562 	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1563 		vmem_dump(vm, pr);
1564 	}
1565 }
1566 
1567 void
1568 vmem_print(uintptr_t addr, const char *modif, void (*pr)(const char *, ...))
1569 {
1570 	const vmem_t *vm = (const void *)addr;
1571 
1572 	vmem_dump(vm, pr);
1573 }
1574 #endif /* defined(DDB) */
1575 
1576 #if defined(_KERNEL)
1577 #define vmem_printf printf
1578 #else
1579 #include <stdio.h>
1580 #include <stdarg.h>
1581 
1582 static void
1583 vmem_printf(const char *fmt, ...)
1584 {
1585 	va_list ap;
1586 	va_start(ap, fmt);
1587 	vprintf(fmt, ap);
1588 	va_end(ap);
1589 }
1590 #endif
1591 
1592 #if defined(VMEM_SANITY)
1593 
1594 static bool
1595 vmem_check_sanity(vmem_t *vm)
1596 {
1597 	const bt_t *bt, *bt2;
1598 
1599 	KASSERT(vm != NULL);
1600 
1601 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1602 		if (bt->bt_start > BT_END(bt)) {
1603 			printf("corrupted tag\n");
1604 			bt_dump(bt, vmem_printf);
1605 			return false;
1606 		}
1607 	}
1608 	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1609 		TAILQ_FOREACH(bt2, &vm->vm_seglist, bt_seglist) {
1610 			if (bt == bt2) {
1611 				continue;
1612 			}
1613 			if (BT_ISSPAN_P(bt) != BT_ISSPAN_P(bt2)) {
1614 				continue;
1615 			}
1616 			if (bt->bt_start <= BT_END(bt2) &&
1617 			    bt2->bt_start <= BT_END(bt)) {
1618 				printf("overwrapped tags\n");
1619 				bt_dump(bt, vmem_printf);
1620 				bt_dump(bt2, vmem_printf);
1621 				return false;
1622 			}
1623 		}
1624 	}
1625 
1626 	return true;
1627 }
1628 
1629 static void
1630 vmem_check(vmem_t *vm)
1631 {
1632 
1633 	if (!vmem_check_sanity(vm)) {
1634 		panic("insanity vmem %p", vm);
1635 	}
1636 }
1637 
1638 #endif /* defined(VMEM_SANITY) */
1639 
1640 #if defined(UNITTEST)
1641 int
1642 main(void)
1643 {
1644 	int rc;
1645 	vmem_t *vm;
1646 	vmem_addr_t p;
1647 	struct reg {
1648 		vmem_addr_t p;
1649 		vmem_size_t sz;
1650 		bool x;
1651 	} *reg = NULL;
1652 	int nreg = 0;
1653 	int nalloc = 0;
1654 	int nfree = 0;
1655 	vmem_size_t total = 0;
1656 #if 1
1657 	vm_flag_t strat = VM_INSTANTFIT;
1658 #else
1659 	vm_flag_t strat = VM_BESTFIT;
1660 #endif
1661 
1662 	vm = vmem_create("test", 0, 0, 1, NULL, NULL, NULL, 0, VM_SLEEP,
1663 #ifdef _KERNEL
1664 	    IPL_NONE
1665 #else
1666 	    0
1667 #endif
1668 	    );
1669 	if (vm == NULL) {
1670 		printf("vmem_create\n");
1671 		exit(EXIT_FAILURE);
1672 	}
1673 	vmem_dump(vm, vmem_printf);
1674 
1675 	rc = vmem_add(vm, 0, 50, VM_SLEEP);
1676 	assert(rc == 0);
1677 	rc = vmem_add(vm, 100, 200, VM_SLEEP);
1678 	assert(rc == 0);
1679 	rc = vmem_add(vm, 2000, 1, VM_SLEEP);
1680 	assert(rc == 0);
1681 	rc = vmem_add(vm, 40000, 65536, VM_SLEEP);
1682 	assert(rc == 0);
1683 	rc = vmem_add(vm, 10000, 10000, VM_SLEEP);
1684 	assert(rc == 0);
1685 	rc = vmem_add(vm, 500, 1000, VM_SLEEP);
1686 	assert(rc == 0);
1687 	rc = vmem_add(vm, 0xffffff00, 0x100, VM_SLEEP);
1688 	assert(rc == 0);
1689 	rc = vmem_xalloc(vm, 0x101, 0, 0, 0,
1690 	    0xffffff00, 0xffffffff, strat|VM_SLEEP, &p);
1691 	assert(rc != 0);
1692 	rc = vmem_xalloc(vm, 50, 0, 0, 0, 0, 49, strat|VM_SLEEP, &p);
1693 	assert(rc == 0 && p == 0);
1694 	vmem_xfree(vm, p, 50);
1695 	rc = vmem_xalloc(vm, 25, 0, 0, 0, 0, 24, strat|VM_SLEEP, &p);
1696 	assert(rc == 0 && p == 0);
1697 	rc = vmem_xalloc(vm, 0x100, 0, 0, 0,
1698 	    0xffffff01, 0xffffffff, strat|VM_SLEEP, &p);
1699 	assert(rc != 0);
1700 	rc = vmem_xalloc(vm, 0x100, 0, 0, 0,
1701 	    0xffffff00, 0xfffffffe, strat|VM_SLEEP, &p);
1702 	assert(rc != 0);
1703 	rc = vmem_xalloc(vm, 0x100, 0, 0, 0,
1704 	    0xffffff00, 0xffffffff, strat|VM_SLEEP, &p);
1705 	assert(rc == 0);
1706 	vmem_dump(vm, vmem_printf);
1707 	for (;;) {
1708 		struct reg *r;
1709 		int t = rand() % 100;
1710 
1711 		if (t > 45) {
1712 			/* alloc */
1713 			vmem_size_t sz = rand() % 500 + 1;
1714 			bool x;
1715 			vmem_size_t align, phase, nocross;
1716 			vmem_addr_t minaddr, maxaddr;
1717 
1718 			if (t > 70) {
1719 				x = true;
1720 				/* XXX */
1721 				align = 1 << (rand() % 15);
1722 				phase = rand() % 65536;
1723 				nocross = 1 << (rand() % 15);
1724 				if (align <= phase) {
1725 					phase = 0;
1726 				}
1727 				if (VMEM_CROSS_P(phase, phase + sz - 1,
1728 				    nocross)) {
1729 					nocross = 0;
1730 				}
1731 				do {
1732 					minaddr = rand() % 50000;
1733 					maxaddr = rand() % 70000;
1734 				} while (minaddr > maxaddr);
1735 				printf("=== xalloc %" PRIu64
1736 				    " align=%" PRIu64 ", phase=%" PRIu64
1737 				    ", nocross=%" PRIu64 ", min=%" PRIu64
1738 				    ", max=%" PRIu64 "\n",
1739 				    (uint64_t)sz,
1740 				    (uint64_t)align,
1741 				    (uint64_t)phase,
1742 				    (uint64_t)nocross,
1743 				    (uint64_t)minaddr,
1744 				    (uint64_t)maxaddr);
1745 				rc = vmem_xalloc(vm, sz, align, phase, nocross,
1746 				    minaddr, maxaddr, strat|VM_SLEEP, &p);
1747 			} else {
1748 				x = false;
1749 				printf("=== alloc %" PRIu64 "\n", (uint64_t)sz);
1750 				rc = vmem_alloc(vm, sz, strat|VM_SLEEP, &p);
1751 			}
1752 			printf("-> %" PRIu64 "\n", (uint64_t)p);
1753 			vmem_dump(vm, vmem_printf);
1754 			if (rc != 0) {
1755 				if (x) {
1756 					continue;
1757 				}
1758 				break;
1759 			}
1760 			nreg++;
1761 			reg = realloc(reg, sizeof(*reg) * nreg);
1762 			r = &reg[nreg - 1];
1763 			r->p = p;
1764 			r->sz = sz;
1765 			r->x = x;
1766 			total += sz;
1767 			nalloc++;
1768 		} else if (nreg != 0) {
1769 			/* free */
1770 			r = &reg[rand() % nreg];
1771 			printf("=== free %" PRIu64 ", %" PRIu64 "\n",
1772 			    (uint64_t)r->p, (uint64_t)r->sz);
1773 			if (r->x) {
1774 				vmem_xfree(vm, r->p, r->sz);
1775 			} else {
1776 				vmem_free(vm, r->p, r->sz);
1777 			}
1778 			total -= r->sz;
1779 			vmem_dump(vm, vmem_printf);
1780 			*r = reg[nreg - 1];
1781 			nreg--;
1782 			nfree++;
1783 		}
1784 		printf("total=%" PRIu64 "\n", (uint64_t)total);
1785 	}
1786 	fprintf(stderr, "total=%" PRIu64 ", nalloc=%d, nfree=%d\n",
1787 	    (uint64_t)total, nalloc, nfree);
1788 	exit(EXIT_SUCCESS);
1789 }
1790 #endif /* defined(UNITTEST) */
1791