subr_vmem.c revision 254025
1/*-
2 * Copyright (c)2006,2007,2008,2009 YAMAMOTO Takashi,
3 * Copyright (c) 2013 EMC Corp.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28/*
29 * From:
30 *	$NetBSD: vmem_impl.h,v 1.2 2013/01/29 21:26:24 para Exp $
31 *	$NetBSD: subr_vmem.c,v 1.83 2013/03/06 11:20:10 yamt Exp $
32 */
33
34/*
35 * reference:
36 * -	Magazines and Vmem: Extending the Slab Allocator
37 *	to Many CPUs and Arbitrary Resources
38 *	http://www.usenix.org/event/usenix01/bonwick.html
39 */
40
41#include <sys/cdefs.h>
42__FBSDID("$FreeBSD: head/sys/kern/subr_vmem.c 254025 2013-08-07 06:21:20Z jeff $");
43
44#include "opt_ddb.h"
45
46#include <sys/param.h>
47#include <sys/systm.h>
48#include <sys/kernel.h>
49#include <sys/queue.h>
50#include <sys/callout.h>
51#include <sys/hash.h>
52#include <sys/lock.h>
53#include <sys/malloc.h>
54#include <sys/mutex.h>
55#include <sys/smp.h>
56#include <sys/condvar.h>
57#include <sys/taskqueue.h>
58#include <sys/vmem.h>
59
60#include <vm/uma.h>
61#include <vm/vm.h>
62#include <vm/pmap.h>
63#include <vm/vm_map.h>
64#include <vm/vm_object.h>
65#include <vm/vm_kern.h>
66#include <vm/vm_extern.h>
67#include <vm/vm_param.h>
68#include <vm/vm_pageout.h>
69
70#define	VMEM_MAXORDER		(sizeof(vmem_size_t) * NBBY)
71
72#define	VMEM_HASHSIZE_MIN	16
73#define	VMEM_HASHSIZE_MAX	131072
74
75#define	VMEM_QCACHE_IDX_MAX	16
76
77#define	VMEM_FITMASK	(M_BESTFIT | M_FIRSTFIT)
78
79#define	VMEM_FLAGS						\
80    (M_NOWAIT | M_WAITOK | M_USE_RESERVE | M_NOVM | M_BESTFIT | M_FIRSTFIT)
81
82#define	BT_FLAGS	(M_NOWAIT | M_WAITOK | M_USE_RESERVE | M_NOVM)
83
84#define	QC_NAME_MAX	16
85
86/*
87 * Data structures private to vmem.
88 */
89MALLOC_DEFINE(M_VMEM, "vmem", "vmem internal structures");
90
91typedef struct vmem_btag bt_t;
92
93TAILQ_HEAD(vmem_seglist, vmem_btag);
94LIST_HEAD(vmem_freelist, vmem_btag);
95LIST_HEAD(vmem_hashlist, vmem_btag);
96
97struct qcache {
98	uma_zone_t	qc_cache;
99	vmem_t 		*qc_vmem;
100	vmem_size_t	qc_size;
101	char		qc_name[QC_NAME_MAX];
102};
103typedef struct qcache qcache_t;
104#define	QC_POOL_TO_QCACHE(pool)	((qcache_t *)(pool->pr_qcache))
105
106#define	VMEM_NAME_MAX	16
107
108/* vmem arena */
109struct vmem {
110	struct mtx_padalign	vm_lock;
111	struct cv		vm_cv;
112	char			vm_name[VMEM_NAME_MAX+1];
113	LIST_ENTRY(vmem)	vm_alllist;
114	struct vmem_hashlist	vm_hash0[VMEM_HASHSIZE_MIN];
115	struct vmem_freelist	vm_freelist[VMEM_MAXORDER];
116	struct vmem_seglist	vm_seglist;
117	struct vmem_hashlist	*vm_hashlist;
118	vmem_size_t		vm_hashsize;
119
120	/* Constant after init */
121	vmem_size_t		vm_qcache_max;
122	vmem_size_t		vm_quantum_mask;
123	vmem_size_t		vm_import_quantum;
124	int			vm_quantum_shift;
125
126	/* Written on alloc/free */
127	LIST_HEAD(, vmem_btag)	vm_freetags;
128	int			vm_nfreetags;
129	int			vm_nbusytag;
130	vmem_size_t		vm_inuse;
131	vmem_size_t		vm_size;
132
133	/* Used on import. */
134	vmem_import_t		*vm_importfn;
135	vmem_release_t		*vm_releasefn;
136	void			*vm_arg;
137
138	/* Space exhaustion callback. */
139	vmem_reclaim_t		*vm_reclaimfn;
140
141	/* quantum cache */
142	qcache_t		vm_qcache[VMEM_QCACHE_IDX_MAX];
143};
144
145/* boundary tag */
146struct vmem_btag {
147	TAILQ_ENTRY(vmem_btag) bt_seglist;
148	union {
149		LIST_ENTRY(vmem_btag) u_freelist; /* BT_TYPE_FREE */
150		LIST_ENTRY(vmem_btag) u_hashlist; /* BT_TYPE_BUSY */
151	} bt_u;
152#define	bt_hashlist	bt_u.u_hashlist
153#define	bt_freelist	bt_u.u_freelist
154	vmem_addr_t	bt_start;
155	vmem_size_t	bt_size;
156	int		bt_type;
157};
158
159#define	BT_TYPE_SPAN		1	/* Allocated from importfn */
160#define	BT_TYPE_SPAN_STATIC	2	/* vmem_add() or create. */
161#define	BT_TYPE_FREE		3	/* Available space. */
162#define	BT_TYPE_BUSY		4	/* Used space. */
163#define	BT_ISSPAN_P(bt)	((bt)->bt_type <= BT_TYPE_SPAN_STATIC)
164
165#define	BT_END(bt)	((bt)->bt_start + (bt)->bt_size - 1)
166
167#if defined(DIAGNOSTIC)
168static void vmem_check(vmem_t *);
169#endif
170
171static struct callout	vmem_periodic_ch;
172static int		vmem_periodic_interval;
173static struct task	vmem_periodic_wk;
174
175static struct mtx_padalign vmem_list_lock;
176static LIST_HEAD(, vmem) vmem_list = LIST_HEAD_INITIALIZER(vmem_list);
177
178/* ---- misc */
179#define	VMEM_CONDVAR_INIT(vm, wchan)	cv_init(&vm->vm_cv, wchan)
180#define	VMEM_CONDVAR_DESTROY(vm)	cv_destroy(&vm->vm_cv)
181#define	VMEM_CONDVAR_WAIT(vm)		cv_wait(&vm->vm_cv, &vm->vm_lock)
182#define	VMEM_CONDVAR_BROADCAST(vm)	cv_broadcast(&vm->vm_cv)
183
184
185#define	VMEM_LOCK(vm)		mtx_lock(&vm->vm_lock)
186#define	VMEM_TRYLOCK(vm)	mtx_trylock(&vm->vm_lock)
187#define	VMEM_UNLOCK(vm)		mtx_unlock(&vm->vm_lock)
188#define	VMEM_LOCK_INIT(vm, name) mtx_init(&vm->vm_lock, (name), NULL, MTX_DEF)
189#define	VMEM_LOCK_DESTROY(vm)	mtx_destroy(&vm->vm_lock)
190#define	VMEM_ASSERT_LOCKED(vm)	mtx_assert(&vm->vm_lock, MA_OWNED);
191
192#define	VMEM_ALIGNUP(addr, align)	(-(-(addr) & -(align)))
193
194#define	VMEM_CROSS_P(addr1, addr2, boundary) \
195	((((addr1) ^ (addr2)) & -(boundary)) != 0)
196
197#define	ORDER2SIZE(order)	((vmem_size_t)1 << (order))
198#define	SIZE2ORDER(size)	((int)flsl(size) - 1)
199
200/*
201 * Maximum number of boundary tags that may be required to satisfy an
202 * allocation.  Two may be required to import.  Another two may be
203 * required to clip edges.
204 */
205#define	BT_MAXALLOC	4
206
207/*
208 * Max free limits the number of locally cached boundary tags.  We
209 * just want to avoid hitting the zone allocator for every call.
210 */
211#define BT_MAXFREE	(BT_MAXALLOC * 8)
212
213/* Allocator for boundary tags. */
214static uma_zone_t vmem_bt_zone;
215
216/* boot time arena storage. */
217static struct vmem kernel_arena_storage;
218static struct vmem kmem_arena_storage;
219static struct vmem buffer_arena_storage;
220static struct vmem transient_arena_storage;
221vmem_t *kernel_arena = &kernel_arena_storage;
222vmem_t *kmem_arena = &kmem_arena_storage;
223vmem_t *buffer_arena = &buffer_arena_storage;
224vmem_t *transient_arena = &transient_arena_storage;
225
226/*
227 * Fill the vmem's boundary tag cache.  We guarantee that boundary tag
228 * allocation will not fail once bt_fill() passes.  To do so we cache
229 * at least the maximum possible tag allocations in the arena.
230 */
231static int
232bt_fill(vmem_t *vm, int flags)
233{
234	bt_t *bt;
235
236	VMEM_ASSERT_LOCKED(vm);
237
238	/*
239	 * Only allow the kmem arena to dip into reserve tags.  It is the
240	 * vmem where new tags come from.
241	 */
242	flags &= BT_FLAGS;
243	if (vm != kmem_arena)
244		flags &= ~M_USE_RESERVE;
245
246	/*
247	 * Loop until we meet the reserve.  To minimize the lock shuffle
248	 * and prevent simultaneous fills we first try a NOWAIT regardless
249	 * of the caller's flags.  Specify M_NOVM so we don't recurse while
250	 * holding a vmem lock.
251	 */
252	while (vm->vm_nfreetags < BT_MAXALLOC) {
253		bt = uma_zalloc(vmem_bt_zone,
254		    (flags & M_USE_RESERVE) | M_NOWAIT | M_NOVM);
255		if (bt == NULL) {
256			VMEM_UNLOCK(vm);
257			bt = uma_zalloc(vmem_bt_zone, flags);
258			VMEM_LOCK(vm);
259			if (bt == NULL && (flags & M_NOWAIT) != 0)
260				break;
261		}
262		LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
263		vm->vm_nfreetags++;
264	}
265
266	if (vm->vm_nfreetags < BT_MAXALLOC)
267		return ENOMEM;
268
269	return 0;
270}
271
272/*
273 * Pop a tag off of the freetag stack.
274 */
275static bt_t *
276bt_alloc(vmem_t *vm)
277{
278	bt_t *bt;
279
280	VMEM_ASSERT_LOCKED(vm);
281	bt = LIST_FIRST(&vm->vm_freetags);
282	MPASS(bt != NULL);
283	LIST_REMOVE(bt, bt_freelist);
284	vm->vm_nfreetags--;
285
286	return bt;
287}
288
289/*
290 * Trim the per-vmem free list.  Returns with the lock released to
291 * avoid allocator recursions.
292 */
293static void
294bt_freetrim(vmem_t *vm, int freelimit)
295{
296	LIST_HEAD(, vmem_btag) freetags;
297	bt_t *bt;
298
299	LIST_INIT(&freetags);
300	VMEM_ASSERT_LOCKED(vm);
301	while (vm->vm_nfreetags > freelimit) {
302		bt = LIST_FIRST(&vm->vm_freetags);
303		LIST_REMOVE(bt, bt_freelist);
304		vm->vm_nfreetags--;
305		LIST_INSERT_HEAD(&freetags, bt, bt_freelist);
306	}
307	VMEM_UNLOCK(vm);
308	while ((bt = LIST_FIRST(&freetags)) != NULL) {
309		LIST_REMOVE(bt, bt_freelist);
310		uma_zfree(vmem_bt_zone, bt);
311	}
312}
313
314static inline void
315bt_free(vmem_t *vm, bt_t *bt)
316{
317
318	VMEM_ASSERT_LOCKED(vm);
319	MPASS(LIST_FIRST(&vm->vm_freetags) != bt);
320	LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
321	vm->vm_nfreetags++;
322}
323
324/*
325 * freelist[0] ... [1, 1]
326 * freelist[1] ... [2, 3]
327 * freelist[2] ... [4, 7]
328 * freelist[3] ... [8, 15]
329 *  :
330 * freelist[n] ... [(1 << n), (1 << (n + 1)) - 1]
331 *  :
332 */
333
334static struct vmem_freelist *
335bt_freehead_tofree(vmem_t *vm, vmem_size_t size)
336{
337	const vmem_size_t qsize = size >> vm->vm_quantum_shift;
338	const int idx = SIZE2ORDER(qsize);
339
340	MPASS(size != 0 && qsize != 0);
341	MPASS((size & vm->vm_quantum_mask) == 0);
342	MPASS(idx >= 0);
343	MPASS(idx < VMEM_MAXORDER);
344
345	return &vm->vm_freelist[idx];
346}
347
348/*
349 * bt_freehead_toalloc: return the freelist for the given size and allocation
350 * strategy.
351 *
352 * For M_FIRSTFIT, return the list in which any blocks are large enough
353 * for the requested size.  otherwise, return the list which can have blocks
354 * large enough for the requested size.
355 */
356static struct vmem_freelist *
357bt_freehead_toalloc(vmem_t *vm, vmem_size_t size, int strat)
358{
359	const vmem_size_t qsize = size >> vm->vm_quantum_shift;
360	int idx = SIZE2ORDER(qsize);
361
362	MPASS(size != 0 && qsize != 0);
363	MPASS((size & vm->vm_quantum_mask) == 0);
364
365	if (strat == M_FIRSTFIT && ORDER2SIZE(idx) != qsize) {
366		idx++;
367		/* check too large request? */
368	}
369	MPASS(idx >= 0);
370	MPASS(idx < VMEM_MAXORDER);
371
372	return &vm->vm_freelist[idx];
373}
374
375/* ---- boundary tag hash */
376
377static struct vmem_hashlist *
378bt_hashhead(vmem_t *vm, vmem_addr_t addr)
379{
380	struct vmem_hashlist *list;
381	unsigned int hash;
382
383	hash = hash32_buf(&addr, sizeof(addr), 0);
384	list = &vm->vm_hashlist[hash % vm->vm_hashsize];
385
386	return list;
387}
388
389static bt_t *
390bt_lookupbusy(vmem_t *vm, vmem_addr_t addr)
391{
392	struct vmem_hashlist *list;
393	bt_t *bt;
394
395	VMEM_ASSERT_LOCKED(vm);
396	list = bt_hashhead(vm, addr);
397	LIST_FOREACH(bt, list, bt_hashlist) {
398		if (bt->bt_start == addr) {
399			break;
400		}
401	}
402
403	return bt;
404}
405
406static void
407bt_rembusy(vmem_t *vm, bt_t *bt)
408{
409
410	VMEM_ASSERT_LOCKED(vm);
411	MPASS(vm->vm_nbusytag > 0);
412	vm->vm_inuse -= bt->bt_size;
413	vm->vm_nbusytag--;
414	LIST_REMOVE(bt, bt_hashlist);
415}
416
417static void
418bt_insbusy(vmem_t *vm, bt_t *bt)
419{
420	struct vmem_hashlist *list;
421
422	VMEM_ASSERT_LOCKED(vm);
423	MPASS(bt->bt_type == BT_TYPE_BUSY);
424
425	list = bt_hashhead(vm, bt->bt_start);
426	LIST_INSERT_HEAD(list, bt, bt_hashlist);
427	vm->vm_nbusytag++;
428	vm->vm_inuse += bt->bt_size;
429}
430
431/* ---- boundary tag list */
432
433static void
434bt_remseg(vmem_t *vm, bt_t *bt)
435{
436
437	TAILQ_REMOVE(&vm->vm_seglist, bt, bt_seglist);
438	bt_free(vm, bt);
439}
440
441static void
442bt_insseg(vmem_t *vm, bt_t *bt, bt_t *prev)
443{
444
445	TAILQ_INSERT_AFTER(&vm->vm_seglist, prev, bt, bt_seglist);
446}
447
448static void
449bt_insseg_tail(vmem_t *vm, bt_t *bt)
450{
451
452	TAILQ_INSERT_TAIL(&vm->vm_seglist, bt, bt_seglist);
453}
454
455static void
456bt_remfree(vmem_t *vm, bt_t *bt)
457{
458
459	MPASS(bt->bt_type == BT_TYPE_FREE);
460
461	LIST_REMOVE(bt, bt_freelist);
462}
463
464static void
465bt_insfree(vmem_t *vm, bt_t *bt)
466{
467	struct vmem_freelist *list;
468
469	list = bt_freehead_tofree(vm, bt->bt_size);
470	LIST_INSERT_HEAD(list, bt, bt_freelist);
471}
472
473/* ---- vmem internal functions */
474
475/*
476 * Import from the arena into the quantum cache in UMA.
477 */
478static int
479qc_import(void *arg, void **store, int cnt, int flags)
480{
481	qcache_t *qc;
482	vmem_addr_t addr;
483	int i;
484
485	qc = arg;
486	flags |= M_BESTFIT;
487	for (i = 0; i < cnt; i++) {
488		if (vmem_xalloc(qc->qc_vmem, qc->qc_size, 0, 0, 0,
489		    VMEM_ADDR_MIN, VMEM_ADDR_MAX, flags, &addr) != 0)
490			break;
491		store[i] = (void *)addr;
492		/* Only guarantee one allocation. */
493		flags &= ~M_WAITOK;
494		flags |= M_NOWAIT;
495	}
496	return i;
497}
498
499/*
500 * Release memory from the UMA cache to the arena.
501 */
502static void
503qc_release(void *arg, void **store, int cnt)
504{
505	qcache_t *qc;
506	int i;
507
508	qc = arg;
509	for (i = 0; i < cnt; i++)
510		vmem_xfree(qc->qc_vmem, (vmem_addr_t)store[i], qc->qc_size);
511}
512
513static void
514qc_init(vmem_t *vm, vmem_size_t qcache_max)
515{
516	qcache_t *qc;
517	vmem_size_t size;
518	int qcache_idx_max;
519	int i;
520
521	MPASS((qcache_max & vm->vm_quantum_mask) == 0);
522	qcache_idx_max = MIN(qcache_max >> vm->vm_quantum_shift,
523	    VMEM_QCACHE_IDX_MAX);
524	vm->vm_qcache_max = qcache_idx_max << vm->vm_quantum_shift;
525	for (i = 0; i < qcache_idx_max; i++) {
526		qc = &vm->vm_qcache[i];
527		size = (i + 1) << vm->vm_quantum_shift;
528		snprintf(qc->qc_name, sizeof(qc->qc_name), "%s-%zu",
529		    vm->vm_name, size);
530		qc->qc_vmem = vm;
531		qc->qc_size = size;
532		qc->qc_cache = uma_zcache_create(qc->qc_name, size,
533		    NULL, NULL, NULL, NULL, qc_import, qc_release, qc,
534		    UMA_ZONE_VM);
535		MPASS(qc->qc_cache);
536	}
537}
538
539static void
540qc_destroy(vmem_t *vm)
541{
542	int qcache_idx_max;
543	int i;
544
545	qcache_idx_max = vm->vm_qcache_max >> vm->vm_quantum_shift;
546	for (i = 0; i < qcache_idx_max; i++)
547		uma_zdestroy(vm->vm_qcache[i].qc_cache);
548}
549
550static void
551qc_drain(vmem_t *vm)
552{
553	int qcache_idx_max;
554	int i;
555
556	qcache_idx_max = vm->vm_qcache_max >> vm->vm_quantum_shift;
557	for (i = 0; i < qcache_idx_max; i++)
558		zone_drain(vm->vm_qcache[i].qc_cache);
559}
560
561#ifndef UMA_MD_SMALL_ALLOC
562
563static struct mtx_padalign vmem_bt_lock;
564
565/*
566 * vmem_bt_alloc:  Allocate a new page of boundary tags.
567 *
568 * On architectures with uma_small_alloc there is no recursion; no address
569 * space need be allocated to allocate boundary tags.  For the others, we
570 * must handle recursion.  Boundary tags are necessary to allocate new
571 * boundary tags.
572 *
573 * UMA guarantees that enough tags are held in reserve to allocate a new
574 * page of kva.  We dip into this reserve by specifying M_USE_RESERVE only
575 * when allocating the page to hold new boundary tags.  In this way the
576 * reserve is automatically filled by the allocation that uses the reserve.
577 *
578 * We still have to guarantee that the new tags are allocated atomically since
579 * many threads may try concurrently.  The bt_lock provides this guarantee.
580 * We convert WAITOK allocations to NOWAIT and then handle the blocking here
581 * on failure.  It's ok to return NULL for a WAITOK allocation as UMA will
582 * loop again after checking to see if we lost the race to allocate.
583 *
584 * There is a small race between vmem_bt_alloc() returning the page and the
585 * zone lock being acquired to add the page to the zone.  For WAITOK
586 * allocations we just pause briefly.  NOWAIT may experience a transient
587 * failure.  To alleviate this we permit a small number of simultaneous
588 * fills to proceed concurrently so NOWAIT is less likely to fail unless
589 * we are really out of KVA.
590 */
591static void *
592vmem_bt_alloc(uma_zone_t zone, int bytes, uint8_t *pflag, int wait)
593{
594	vmem_addr_t addr;
595
596	*pflag = UMA_SLAB_KMEM;
597
598	/*
599	 * Single thread boundary tag allocation so that the address space
600	 * and memory are added in one atomic operation.
601	 */
602	mtx_lock(&vmem_bt_lock);
603	if (vmem_xalloc(kmem_arena, bytes, 0, 0, 0, VMEM_ADDR_MIN,
604	    VMEM_ADDR_MAX, M_NOWAIT | M_NOVM | M_USE_RESERVE | M_BESTFIT,
605	    &addr) == 0) {
606		if (kmem_back(kmem_object, addr, bytes,
607		    M_NOWAIT | M_USE_RESERVE) == 0) {
608			mtx_unlock(&vmem_bt_lock);
609			return ((void *)addr);
610		}
611		vmem_xfree(kmem_arena, addr, bytes);
612		mtx_unlock(&vmem_bt_lock);
613		/*
614		 * Out of memory, not address space.  This may not even be
615		 * possible due to M_USE_RESERVE page allocation.
616		 */
617		if (wait & M_WAITOK)
618			VM_WAIT;
619		return (NULL);
620	}
621	mtx_unlock(&vmem_bt_lock);
622	/*
623	 * We're either out of address space or lost a fill race.
624	 */
625	if (wait & M_WAITOK)
626		pause("btalloc", 1);
627
628	return (NULL);
629}
630#endif
631
632void
633vmem_startup(void)
634{
635
636	mtx_init(&vmem_list_lock, "vmem list lock", NULL, MTX_DEF);
637	vmem_bt_zone = uma_zcreate("vmem btag",
638	    sizeof(struct vmem_btag), NULL, NULL, NULL, NULL,
639	    UMA_ALIGN_PTR, UMA_ZONE_VM);
640#ifndef UMA_MD_SMALL_ALLOC
641	mtx_init(&vmem_bt_lock, "btag lock", NULL, MTX_DEF);
642	uma_prealloc(vmem_bt_zone, BT_MAXALLOC);
643	/*
644	 * Reserve enough tags to allocate new tags.  We allow multiple
645	 * CPUs to attempt to allocate new tags concurrently to limit
646	 * false restarts in UMA.
647	 */
648	uma_zone_reserve(vmem_bt_zone, BT_MAXALLOC * (mp_ncpus + 1) / 2);
649	uma_zone_set_allocf(vmem_bt_zone, vmem_bt_alloc);
650#endif
651}
652
653/* ---- rehash */
654
655static int
656vmem_rehash(vmem_t *vm, vmem_size_t newhashsize)
657{
658	bt_t *bt;
659	int i;
660	struct vmem_hashlist *newhashlist;
661	struct vmem_hashlist *oldhashlist;
662	vmem_size_t oldhashsize;
663
664	MPASS(newhashsize > 0);
665
666	newhashlist = malloc(sizeof(struct vmem_hashlist) * newhashsize,
667	    M_VMEM, M_NOWAIT);
668	if (newhashlist == NULL)
669		return ENOMEM;
670	for (i = 0; i < newhashsize; i++) {
671		LIST_INIT(&newhashlist[i]);
672	}
673
674	VMEM_LOCK(vm);
675	oldhashlist = vm->vm_hashlist;
676	oldhashsize = vm->vm_hashsize;
677	vm->vm_hashlist = newhashlist;
678	vm->vm_hashsize = newhashsize;
679	if (oldhashlist == NULL) {
680		VMEM_UNLOCK(vm);
681		return 0;
682	}
683	for (i = 0; i < oldhashsize; i++) {
684		while ((bt = LIST_FIRST(&oldhashlist[i])) != NULL) {
685			bt_rembusy(vm, bt);
686			bt_insbusy(vm, bt);
687		}
688	}
689	VMEM_UNLOCK(vm);
690
691	if (oldhashlist != vm->vm_hash0) {
692		free(oldhashlist, M_VMEM);
693	}
694
695	return 0;
696}
697
698static void
699vmem_periodic_kick(void *dummy)
700{
701
702	taskqueue_enqueue(taskqueue_thread, &vmem_periodic_wk);
703}
704
705static void
706vmem_periodic(void *unused, int pending)
707{
708	vmem_t *vm;
709	vmem_size_t desired;
710	vmem_size_t current;
711
712	mtx_lock(&vmem_list_lock);
713	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
714#ifdef DIAGNOSTIC
715		/* Convenient time to verify vmem state. */
716		VMEM_LOCK(vm);
717		vmem_check(vm);
718		VMEM_UNLOCK(vm);
719#endif
720		desired = 1 << flsl(vm->vm_nbusytag);
721		desired = MIN(MAX(desired, VMEM_HASHSIZE_MIN),
722		    VMEM_HASHSIZE_MAX);
723		current = vm->vm_hashsize;
724
725		/* Grow in powers of two.  Shrink less aggressively. */
726		if (desired >= current * 2 || desired * 4 <= current)
727			vmem_rehash(vm, desired);
728	}
729	mtx_unlock(&vmem_list_lock);
730
731	callout_reset(&vmem_periodic_ch, vmem_periodic_interval,
732	    vmem_periodic_kick, NULL);
733}
734
735static void
736vmem_start_callout(void *unused)
737{
738
739	TASK_INIT(&vmem_periodic_wk, 0, vmem_periodic, NULL);
740	vmem_periodic_interval = hz * 10;
741	callout_init(&vmem_periodic_ch, CALLOUT_MPSAFE);
742	callout_reset(&vmem_periodic_ch, vmem_periodic_interval,
743	    vmem_periodic_kick, NULL);
744}
745SYSINIT(vfs, SI_SUB_CONFIGURE, SI_ORDER_ANY, vmem_start_callout, NULL);
746
747static void
748vmem_add1(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, int type)
749{
750	bt_t *btspan;
751	bt_t *btfree;
752
753	MPASS(type == BT_TYPE_SPAN || type == BT_TYPE_SPAN_STATIC);
754
755	btspan = bt_alloc(vm);
756	btspan->bt_type = type;
757	btspan->bt_start = addr;
758	btspan->bt_size = size;
759	bt_insseg_tail(vm, btspan);
760
761	btfree = bt_alloc(vm);
762	btfree->bt_type = BT_TYPE_FREE;
763	btfree->bt_start = addr;
764	btfree->bt_size = size;
765	bt_insseg(vm, btfree, btspan);
766	bt_insfree(vm, btfree);
767
768	vm->vm_size += size;
769}
770
771static void
772vmem_destroy1(vmem_t *vm)
773{
774	bt_t *bt;
775
776	/*
777	 * Drain per-cpu quantum caches.
778	 */
779	qc_destroy(vm);
780
781	/*
782	 * The vmem should now only contain empty segments.
783	 */
784	VMEM_LOCK(vm);
785	MPASS(vm->vm_nbusytag == 0);
786
787	while ((bt = TAILQ_FIRST(&vm->vm_seglist)) != NULL)
788		bt_remseg(vm, bt);
789
790	if (vm->vm_hashlist != NULL && vm->vm_hashlist != vm->vm_hash0)
791		free(vm->vm_hashlist, M_VMEM);
792
793	bt_freetrim(vm, 0);
794
795	VMEM_CONDVAR_DESTROY(vm);
796	VMEM_LOCK_DESTROY(vm);
797	free(vm, M_VMEM);
798}
799
800static int
801vmem_import(vmem_t *vm, vmem_size_t size, int flags)
802{
803	vmem_addr_t addr;
804	int error;
805
806	if (vm->vm_importfn == NULL)
807		return EINVAL;
808
809	size = roundup(size, vm->vm_import_quantum);
810
811	/*
812	 * Hide MAXALLOC tags so we're guaranteed to be able to add this
813	 * span and the tag we want to allocate from it.
814	 */
815	MPASS(vm->vm_nfreetags >= BT_MAXALLOC);
816	vm->vm_nfreetags -= BT_MAXALLOC;
817	VMEM_UNLOCK(vm);
818	error = (vm->vm_importfn)(vm->vm_arg, size, flags, &addr);
819	VMEM_LOCK(vm);
820	vm->vm_nfreetags += BT_MAXALLOC;
821	if (error)
822		return ENOMEM;
823
824	vmem_add1(vm, addr, size, BT_TYPE_SPAN);
825
826	return 0;
827}
828
829/*
830 * vmem_fit: check if a bt can satisfy the given restrictions.
831 *
832 * it's a caller's responsibility to ensure the region is big enough
833 * before calling us.
834 */
835static int
836vmem_fit(const bt_t *bt, vmem_size_t size, vmem_size_t align,
837    vmem_size_t phase, vmem_size_t nocross, vmem_addr_t minaddr,
838    vmem_addr_t maxaddr, vmem_addr_t *addrp)
839{
840	vmem_addr_t start;
841	vmem_addr_t end;
842
843	MPASS(size > 0);
844	MPASS(bt->bt_size >= size); /* caller's responsibility */
845
846	/*
847	 * XXX assumption: vmem_addr_t and vmem_size_t are
848	 * unsigned integer of the same size.
849	 */
850
851	start = bt->bt_start;
852	if (start < minaddr) {
853		start = minaddr;
854	}
855	end = BT_END(bt);
856	if (end > maxaddr)
857		end = maxaddr;
858	if (start > end)
859		return (ENOMEM);
860
861	start = VMEM_ALIGNUP(start - phase, align) + phase;
862	if (start < bt->bt_start)
863		start += align;
864	if (VMEM_CROSS_P(start, start + size - 1, nocross)) {
865		MPASS(align < nocross);
866		start = VMEM_ALIGNUP(start - phase, nocross) + phase;
867	}
868	if (start <= end && end - start >= size - 1) {
869		MPASS((start & (align - 1)) == phase);
870		MPASS(!VMEM_CROSS_P(start, start + size - 1, nocross));
871		MPASS(minaddr <= start);
872		MPASS(maxaddr == 0 || start + size - 1 <= maxaddr);
873		MPASS(bt->bt_start <= start);
874		MPASS(BT_END(bt) - start >= size - 1);
875		*addrp = start;
876
877		return (0);
878	}
879	return (ENOMEM);
880}
881
882/*
883 * vmem_clip:  Trim the boundary tag edges to the requested start and size.
884 */
885static void
886vmem_clip(vmem_t *vm, bt_t *bt, vmem_addr_t start, vmem_size_t size)
887{
888	bt_t *btnew;
889	bt_t *btprev;
890
891	VMEM_ASSERT_LOCKED(vm);
892	MPASS(bt->bt_type == BT_TYPE_FREE);
893	MPASS(bt->bt_size >= size);
894	bt_remfree(vm, bt);
895	if (bt->bt_start != start) {
896		btprev = bt_alloc(vm);
897		btprev->bt_type = BT_TYPE_FREE;
898		btprev->bt_start = bt->bt_start;
899		btprev->bt_size = start - bt->bt_start;
900		bt->bt_start = start;
901		bt->bt_size -= btprev->bt_size;
902		bt_insfree(vm, btprev);
903		bt_insseg(vm, btprev,
904		    TAILQ_PREV(bt, vmem_seglist, bt_seglist));
905	}
906	MPASS(bt->bt_start == start);
907	if (bt->bt_size != size && bt->bt_size - size > vm->vm_quantum_mask) {
908		/* split */
909		btnew = bt_alloc(vm);
910		btnew->bt_type = BT_TYPE_BUSY;
911		btnew->bt_start = bt->bt_start;
912		btnew->bt_size = size;
913		bt->bt_start = bt->bt_start + size;
914		bt->bt_size -= size;
915		bt_insfree(vm, bt);
916		bt_insseg(vm, btnew,
917		    TAILQ_PREV(bt, vmem_seglist, bt_seglist));
918		bt_insbusy(vm, btnew);
919		bt = btnew;
920	} else {
921		bt->bt_type = BT_TYPE_BUSY;
922		bt_insbusy(vm, bt);
923	}
924	MPASS(bt->bt_size >= size);
925	bt->bt_type = BT_TYPE_BUSY;
926}
927
928/* ---- vmem API */
929
930void
931vmem_set_import(vmem_t *vm, vmem_import_t *importfn,
932     vmem_release_t *releasefn, void *arg, vmem_size_t import_quantum)
933{
934
935	VMEM_LOCK(vm);
936	vm->vm_importfn = importfn;
937	vm->vm_releasefn = releasefn;
938	vm->vm_arg = arg;
939	vm->vm_import_quantum = import_quantum;
940	VMEM_UNLOCK(vm);
941}
942
943void
944vmem_set_reclaim(vmem_t *vm, vmem_reclaim_t *reclaimfn)
945{
946
947	VMEM_LOCK(vm);
948	vm->vm_reclaimfn = reclaimfn;
949	VMEM_UNLOCK(vm);
950}
951
952/*
953 * vmem_init: Initializes vmem arena.
954 */
955vmem_t *
956vmem_init(vmem_t *vm, const char *name, vmem_addr_t base, vmem_size_t size,
957    vmem_size_t quantum, vmem_size_t qcache_max, int flags)
958{
959	int i;
960
961	MPASS(quantum > 0);
962
963	bzero(vm, sizeof(*vm));
964
965	VMEM_CONDVAR_INIT(vm, name);
966	VMEM_LOCK_INIT(vm, name);
967	vm->vm_nfreetags = 0;
968	LIST_INIT(&vm->vm_freetags);
969	strlcpy(vm->vm_name, name, sizeof(vm->vm_name));
970	vm->vm_quantum_mask = quantum - 1;
971	vm->vm_quantum_shift = SIZE2ORDER(quantum);
972	MPASS(ORDER2SIZE(vm->vm_quantum_shift) == quantum);
973	vm->vm_nbusytag = 0;
974	vm->vm_size = 0;
975	vm->vm_inuse = 0;
976	qc_init(vm, qcache_max);
977
978	TAILQ_INIT(&vm->vm_seglist);
979	for (i = 0; i < VMEM_MAXORDER; i++) {
980		LIST_INIT(&vm->vm_freelist[i]);
981	}
982	memset(&vm->vm_hash0, 0, sizeof(vm->vm_hash0));
983	vm->vm_hashsize = VMEM_HASHSIZE_MIN;
984	vm->vm_hashlist = vm->vm_hash0;
985
986	if (size != 0) {
987		if (vmem_add(vm, base, size, flags) != 0) {
988			vmem_destroy1(vm);
989			return NULL;
990		}
991	}
992
993	mtx_lock(&vmem_list_lock);
994	LIST_INSERT_HEAD(&vmem_list, vm, vm_alllist);
995	mtx_unlock(&vmem_list_lock);
996
997	return vm;
998}
999
1000/*
1001 * vmem_create: create an arena.
1002 */
1003vmem_t *
1004vmem_create(const char *name, vmem_addr_t base, vmem_size_t size,
1005    vmem_size_t quantum, vmem_size_t qcache_max, int flags)
1006{
1007
1008	vmem_t *vm;
1009
1010	vm = malloc(sizeof(*vm), M_VMEM, flags & (M_WAITOK|M_NOWAIT));
1011	if (vm == NULL)
1012		return (NULL);
1013	if (vmem_init(vm, name, base, size, quantum, qcache_max,
1014	    flags) == NULL) {
1015		free(vm, M_VMEM);
1016		return (NULL);
1017	}
1018	return (vm);
1019}
1020
1021void
1022vmem_destroy(vmem_t *vm)
1023{
1024
1025	mtx_lock(&vmem_list_lock);
1026	LIST_REMOVE(vm, vm_alllist);
1027	mtx_unlock(&vmem_list_lock);
1028
1029	vmem_destroy1(vm);
1030}
1031
1032vmem_size_t
1033vmem_roundup_size(vmem_t *vm, vmem_size_t size)
1034{
1035
1036	return (size + vm->vm_quantum_mask) & ~vm->vm_quantum_mask;
1037}
1038
1039/*
1040 * vmem_alloc: allocate resource from the arena.
1041 */
1042int
1043vmem_alloc(vmem_t *vm, vmem_size_t size, int flags, vmem_addr_t *addrp)
1044{
1045	const int strat __unused = flags & VMEM_FITMASK;
1046	qcache_t *qc;
1047
1048	flags &= VMEM_FLAGS;
1049	MPASS(size > 0);
1050	MPASS(strat == M_BESTFIT || strat == M_FIRSTFIT);
1051	if ((flags & M_NOWAIT) == 0)
1052		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "vmem_alloc");
1053
1054	if (size <= vm->vm_qcache_max) {
1055		qc = &vm->vm_qcache[(size - 1) >> vm->vm_quantum_shift];
1056		*addrp = (vmem_addr_t)uma_zalloc(qc->qc_cache, flags);
1057		if (*addrp == 0)
1058			return (ENOMEM);
1059		return (0);
1060	}
1061
1062	return vmem_xalloc(vm, size, 0, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX,
1063	    flags, addrp);
1064}
1065
1066int
1067vmem_xalloc(vmem_t *vm, const vmem_size_t size0, vmem_size_t align,
1068    const vmem_size_t phase, const vmem_size_t nocross,
1069    const vmem_addr_t minaddr, const vmem_addr_t maxaddr, int flags,
1070    vmem_addr_t *addrp)
1071{
1072	const vmem_size_t size = vmem_roundup_size(vm, size0);
1073	struct vmem_freelist *list;
1074	struct vmem_freelist *first;
1075	struct vmem_freelist *end;
1076	vmem_size_t avail;
1077	bt_t *bt;
1078	int error;
1079	int strat;
1080
1081	flags &= VMEM_FLAGS;
1082	strat = flags & VMEM_FITMASK;
1083	MPASS(size0 > 0);
1084	MPASS(size > 0);
1085	MPASS(strat == M_BESTFIT || strat == M_FIRSTFIT);
1086	MPASS((flags & (M_NOWAIT|M_WAITOK)) != (M_NOWAIT|M_WAITOK));
1087	if ((flags & M_NOWAIT) == 0)
1088		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "vmem_xalloc");
1089	MPASS((align & vm->vm_quantum_mask) == 0);
1090	MPASS((align & (align - 1)) == 0);
1091	MPASS((phase & vm->vm_quantum_mask) == 0);
1092	MPASS((nocross & vm->vm_quantum_mask) == 0);
1093	MPASS((nocross & (nocross - 1)) == 0);
1094	MPASS((align == 0 && phase == 0) || phase < align);
1095	MPASS(nocross == 0 || nocross >= size);
1096	MPASS(minaddr <= maxaddr);
1097	MPASS(!VMEM_CROSS_P(phase, phase + size - 1, nocross));
1098
1099	if (align == 0)
1100		align = vm->vm_quantum_mask + 1;
1101
1102	*addrp = 0;
1103	end = &vm->vm_freelist[VMEM_MAXORDER];
1104	/*
1105	 * choose a free block from which we allocate.
1106	 */
1107	first = bt_freehead_toalloc(vm, size, strat);
1108	VMEM_LOCK(vm);
1109	for (;;) {
1110		/*
1111		 * Make sure we have enough tags to complete the
1112		 * operation.
1113		 */
1114		if (vm->vm_nfreetags < BT_MAXALLOC &&
1115		    bt_fill(vm, flags) != 0) {
1116			error = ENOMEM;
1117			break;
1118		}
1119		/*
1120	 	 * Scan freelists looking for a tag that satisfies the
1121		 * allocation.  If we're doing BESTFIT we may encounter
1122		 * sizes below the request.  If we're doing FIRSTFIT we
1123		 * inspect only the first element from each list.
1124		 */
1125		for (list = first; list < end; list++) {
1126			LIST_FOREACH(bt, list, bt_freelist) {
1127				if (bt->bt_size >= size) {
1128					error = vmem_fit(bt, size, align, phase,
1129					    nocross, minaddr, maxaddr, addrp);
1130					if (error == 0) {
1131						vmem_clip(vm, bt, *addrp, size);
1132						goto out;
1133					}
1134				}
1135				/* FIRST skips to the next list. */
1136				if (strat == M_FIRSTFIT)
1137					break;
1138			}
1139		}
1140		/*
1141		 * Retry if the fast algorithm failed.
1142		 */
1143		if (strat == M_FIRSTFIT) {
1144			strat = M_BESTFIT;
1145			first = bt_freehead_toalloc(vm, size, strat);
1146			continue;
1147		}
1148		/*
1149		 * XXX it is possible to fail to meet restrictions with the
1150		 * imported region.  It is up to the user to specify the
1151		 * import quantum such that it can satisfy any allocation.
1152		 */
1153		if (vmem_import(vm, size, flags) == 0)
1154			continue;
1155
1156		/*
1157		 * Try to free some space from the quantum cache or reclaim
1158		 * functions if available.
1159		 */
1160		if (vm->vm_qcache_max != 0 || vm->vm_reclaimfn != NULL) {
1161			avail = vm->vm_size - vm->vm_inuse;
1162			VMEM_UNLOCK(vm);
1163			if (vm->vm_qcache_max != 0)
1164				qc_drain(vm);
1165			if (vm->vm_reclaimfn != NULL)
1166				vm->vm_reclaimfn(vm, flags);
1167			VMEM_LOCK(vm);
1168			/* If we were successful retry even NOWAIT. */
1169			if (vm->vm_size - vm->vm_inuse > avail)
1170				continue;
1171		}
1172		if ((flags & M_NOWAIT) != 0) {
1173			error = ENOMEM;
1174			break;
1175		}
1176		VMEM_CONDVAR_WAIT(vm);
1177	}
1178out:
1179	VMEM_UNLOCK(vm);
1180	if (error != 0 && (flags & M_NOWAIT) == 0)
1181		panic("failed to allocate waiting allocation\n");
1182
1183	return (error);
1184}
1185
1186/*
1187 * vmem_free: free the resource to the arena.
1188 */
1189void
1190vmem_free(vmem_t *vm, vmem_addr_t addr, vmem_size_t size)
1191{
1192	qcache_t *qc;
1193	MPASS(size > 0);
1194
1195	if (size <= vm->vm_qcache_max) {
1196		qc = &vm->vm_qcache[(size - 1) >> vm->vm_quantum_shift];
1197		uma_zfree(qc->qc_cache, (void *)addr);
1198	} else
1199		vmem_xfree(vm, addr, size);
1200}
1201
1202void
1203vmem_xfree(vmem_t *vm, vmem_addr_t addr, vmem_size_t size)
1204{
1205	bt_t *bt;
1206	bt_t *t;
1207
1208	MPASS(size > 0);
1209
1210	VMEM_LOCK(vm);
1211	bt = bt_lookupbusy(vm, addr);
1212	MPASS(bt != NULL);
1213	MPASS(bt->bt_start == addr);
1214	MPASS(bt->bt_size == vmem_roundup_size(vm, size) ||
1215	    bt->bt_size - vmem_roundup_size(vm, size) <= vm->vm_quantum_mask);
1216	MPASS(bt->bt_type == BT_TYPE_BUSY);
1217	bt_rembusy(vm, bt);
1218	bt->bt_type = BT_TYPE_FREE;
1219
1220	/* coalesce */
1221	t = TAILQ_NEXT(bt, bt_seglist);
1222	if (t != NULL && t->bt_type == BT_TYPE_FREE) {
1223		MPASS(BT_END(bt) < t->bt_start);	/* YYY */
1224		bt->bt_size += t->bt_size;
1225		bt_remfree(vm, t);
1226		bt_remseg(vm, t);
1227	}
1228	t = TAILQ_PREV(bt, vmem_seglist, bt_seglist);
1229	if (t != NULL && t->bt_type == BT_TYPE_FREE) {
1230		MPASS(BT_END(t) < bt->bt_start);	/* YYY */
1231		bt->bt_size += t->bt_size;
1232		bt->bt_start = t->bt_start;
1233		bt_remfree(vm, t);
1234		bt_remseg(vm, t);
1235	}
1236
1237	t = TAILQ_PREV(bt, vmem_seglist, bt_seglist);
1238	MPASS(t != NULL);
1239	MPASS(BT_ISSPAN_P(t) || t->bt_type == BT_TYPE_BUSY);
1240	if (vm->vm_releasefn != NULL && t->bt_type == BT_TYPE_SPAN &&
1241	    t->bt_size == bt->bt_size) {
1242		vmem_addr_t spanaddr;
1243		vmem_size_t spansize;
1244
1245		MPASS(t->bt_start == bt->bt_start);
1246		spanaddr = bt->bt_start;
1247		spansize = bt->bt_size;
1248		bt_remseg(vm, bt);
1249		bt_remseg(vm, t);
1250		vm->vm_size -= spansize;
1251		VMEM_CONDVAR_BROADCAST(vm);
1252		bt_freetrim(vm, BT_MAXFREE);
1253		(*vm->vm_releasefn)(vm->vm_arg, spanaddr, spansize);
1254	} else {
1255		bt_insfree(vm, bt);
1256		VMEM_CONDVAR_BROADCAST(vm);
1257		bt_freetrim(vm, BT_MAXFREE);
1258	}
1259}
1260
1261/*
1262 * vmem_add:
1263 *
1264 */
1265int
1266vmem_add(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, int flags)
1267{
1268	int error;
1269
1270	error = 0;
1271	flags &= VMEM_FLAGS;
1272	VMEM_LOCK(vm);
1273	if (vm->vm_nfreetags >= BT_MAXALLOC || bt_fill(vm, flags) == 0)
1274		vmem_add1(vm, addr, size, BT_TYPE_SPAN_STATIC);
1275	else
1276		error = ENOMEM;
1277	VMEM_UNLOCK(vm);
1278
1279	return (error);
1280}
1281
1282/*
1283 * vmem_size: information about arenas size
1284 */
1285vmem_size_t
1286vmem_size(vmem_t *vm, int typemask)
1287{
1288
1289	switch (typemask) {
1290	case VMEM_ALLOC:
1291		return vm->vm_inuse;
1292	case VMEM_FREE:
1293		return vm->vm_size - vm->vm_inuse;
1294	case VMEM_FREE|VMEM_ALLOC:
1295		return vm->vm_size;
1296	default:
1297		panic("vmem_size");
1298	}
1299}
1300
1301/* ---- debug */
1302
1303#if defined(DDB) || defined(DIAGNOSTIC)
1304
1305static void bt_dump(const bt_t *, int (*)(const char *, ...)
1306    __printflike(1, 2));
1307
1308static const char *
1309bt_type_string(int type)
1310{
1311
1312	switch (type) {
1313	case BT_TYPE_BUSY:
1314		return "busy";
1315	case BT_TYPE_FREE:
1316		return "free";
1317	case BT_TYPE_SPAN:
1318		return "span";
1319	case BT_TYPE_SPAN_STATIC:
1320		return "static span";
1321	default:
1322		break;
1323	}
1324	return "BOGUS";
1325}
1326
1327static void
1328bt_dump(const bt_t *bt, int (*pr)(const char *, ...))
1329{
1330
1331	(*pr)("\t%p: %jx %jx, %d(%s)\n",
1332	    bt, (intmax_t)bt->bt_start, (intmax_t)bt->bt_size,
1333	    bt->bt_type, bt_type_string(bt->bt_type));
1334}
1335
1336static void
1337vmem_dump(const vmem_t *vm , int (*pr)(const char *, ...) __printflike(1, 2))
1338{
1339	const bt_t *bt;
1340	int i;
1341
1342	(*pr)("vmem %p '%s'\n", vm, vm->vm_name);
1343	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1344		bt_dump(bt, pr);
1345	}
1346
1347	for (i = 0; i < VMEM_MAXORDER; i++) {
1348		const struct vmem_freelist *fl = &vm->vm_freelist[i];
1349
1350		if (LIST_EMPTY(fl)) {
1351			continue;
1352		}
1353
1354		(*pr)("freelist[%d]\n", i);
1355		LIST_FOREACH(bt, fl, bt_freelist) {
1356			bt_dump(bt, pr);
1357		}
1358	}
1359}
1360
1361#endif /* defined(DDB) || defined(DIAGNOSTIC) */
1362
1363#if defined(DDB)
1364static bt_t *
1365vmem_whatis_lookup(vmem_t *vm, vmem_addr_t addr)
1366{
1367	bt_t *bt;
1368
1369	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1370		if (BT_ISSPAN_P(bt)) {
1371			continue;
1372		}
1373		if (bt->bt_start <= addr && addr <= BT_END(bt)) {
1374			return bt;
1375		}
1376	}
1377
1378	return NULL;
1379}
1380
1381void
1382vmem_whatis(vmem_addr_t addr, int (*pr)(const char *, ...))
1383{
1384	vmem_t *vm;
1385
1386	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1387		bt_t *bt;
1388
1389		bt = vmem_whatis_lookup(vm, addr);
1390		if (bt == NULL) {
1391			continue;
1392		}
1393		(*pr)("%p is %p+%zu in VMEM '%s' (%s)\n",
1394		    (void *)addr, (void *)bt->bt_start,
1395		    (vmem_size_t)(addr - bt->bt_start), vm->vm_name,
1396		    (bt->bt_type == BT_TYPE_BUSY) ? "allocated" : "free");
1397	}
1398}
1399
1400void
1401vmem_printall(const char *modif, int (*pr)(const char *, ...))
1402{
1403	const vmem_t *vm;
1404
1405	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1406		vmem_dump(vm, pr);
1407	}
1408}
1409
1410void
1411vmem_print(vmem_addr_t addr, const char *modif, int (*pr)(const char *, ...))
1412{
1413	const vmem_t *vm = (const void *)addr;
1414
1415	vmem_dump(vm, pr);
1416}
1417#endif /* defined(DDB) */
1418
1419#define vmem_printf printf
1420
1421#if defined(DIAGNOSTIC)
1422
1423static bool
1424vmem_check_sanity(vmem_t *vm)
1425{
1426	const bt_t *bt, *bt2;
1427
1428	MPASS(vm != NULL);
1429
1430	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1431		if (bt->bt_start > BT_END(bt)) {
1432			printf("corrupted tag\n");
1433			bt_dump(bt, vmem_printf);
1434			return false;
1435		}
1436	}
1437	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1438		TAILQ_FOREACH(bt2, &vm->vm_seglist, bt_seglist) {
1439			if (bt == bt2) {
1440				continue;
1441			}
1442			if (BT_ISSPAN_P(bt) != BT_ISSPAN_P(bt2)) {
1443				continue;
1444			}
1445			if (bt->bt_start <= BT_END(bt2) &&
1446			    bt2->bt_start <= BT_END(bt)) {
1447				printf("overwrapped tags\n");
1448				bt_dump(bt, vmem_printf);
1449				bt_dump(bt2, vmem_printf);
1450				return false;
1451			}
1452		}
1453	}
1454
1455	return true;
1456}
1457
1458static void
1459vmem_check(vmem_t *vm)
1460{
1461
1462	if (!vmem_check_sanity(vm)) {
1463		panic("insanity vmem %p", vm);
1464	}
1465}
1466
1467#endif /* defined(DIAGNOSTIC) */
1468