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: releng/10.3/sys/kern/subr_vmem.c 295870 2016-02-21 22:34:09Z marius $");
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/sysctl.h>
58#include <sys/taskqueue.h>
59#include <sys/vmem.h>
60
61#include "opt_vm.h"
62
63#include <vm/uma.h>
64#include <vm/vm.h>
65#include <vm/pmap.h>
66#include <vm/vm_map.h>
67#include <vm/vm_object.h>
68#include <vm/vm_kern.h>
69#include <vm/vm_extern.h>
70#include <vm/vm_param.h>
71#include <vm/vm_pageout.h>
72
73#define	VMEM_OPTORDER		5
74#define	VMEM_OPTVALUE		(1 << VMEM_OPTORDER)
75#define	VMEM_MAXORDER						\
76    (VMEM_OPTVALUE - 1 + sizeof(vmem_size_t) * NBBY - VMEM_OPTORDER)
77
78#define	VMEM_HASHSIZE_MIN	16
79#define	VMEM_HASHSIZE_MAX	131072
80
81#define	VMEM_QCACHE_IDX_MAX	16
82
83#define	VMEM_FITMASK	(M_BESTFIT | M_FIRSTFIT)
84
85#define	VMEM_FLAGS						\
86    (M_NOWAIT | M_WAITOK | M_USE_RESERVE | M_NOVM | M_BESTFIT | M_FIRSTFIT)
87
88#define	BT_FLAGS	(M_NOWAIT | M_WAITOK | M_USE_RESERVE | M_NOVM)
89
90#define	QC_NAME_MAX	16
91
92/*
93 * Data structures private to vmem.
94 */
95MALLOC_DEFINE(M_VMEM, "vmem", "vmem internal structures");
96
97typedef struct vmem_btag bt_t;
98
99TAILQ_HEAD(vmem_seglist, vmem_btag);
100LIST_HEAD(vmem_freelist, vmem_btag);
101LIST_HEAD(vmem_hashlist, vmem_btag);
102
103struct qcache {
104	uma_zone_t	qc_cache;
105	vmem_t 		*qc_vmem;
106	vmem_size_t	qc_size;
107	char		qc_name[QC_NAME_MAX];
108};
109typedef struct qcache qcache_t;
110#define	QC_POOL_TO_QCACHE(pool)	((qcache_t *)(pool->pr_qcache))
111
112#define	VMEM_NAME_MAX	16
113
114/* vmem arena */
115struct vmem {
116	struct mtx_padalign	vm_lock;
117	struct cv		vm_cv;
118	char			vm_name[VMEM_NAME_MAX+1];
119	LIST_ENTRY(vmem)	vm_alllist;
120	struct vmem_hashlist	vm_hash0[VMEM_HASHSIZE_MIN];
121	struct vmem_freelist	vm_freelist[VMEM_MAXORDER];
122	struct vmem_seglist	vm_seglist;
123	struct vmem_hashlist	*vm_hashlist;
124	vmem_size_t		vm_hashsize;
125
126	/* Constant after init */
127	vmem_size_t		vm_qcache_max;
128	vmem_size_t		vm_quantum_mask;
129	vmem_size_t		vm_import_quantum;
130	int			vm_quantum_shift;
131
132	/* Written on alloc/free */
133	LIST_HEAD(, vmem_btag)	vm_freetags;
134	int			vm_nfreetags;
135	int			vm_nbusytag;
136	vmem_size_t		vm_inuse;
137	vmem_size_t		vm_size;
138
139	/* Used on import. */
140	vmem_import_t		*vm_importfn;
141	vmem_release_t		*vm_releasefn;
142	void			*vm_arg;
143
144	/* Space exhaustion callback. */
145	vmem_reclaim_t		*vm_reclaimfn;
146
147	/* quantum cache */
148	qcache_t		vm_qcache[VMEM_QCACHE_IDX_MAX];
149};
150
151/* boundary tag */
152struct vmem_btag {
153	TAILQ_ENTRY(vmem_btag) bt_seglist;
154	union {
155		LIST_ENTRY(vmem_btag) u_freelist; /* BT_TYPE_FREE */
156		LIST_ENTRY(vmem_btag) u_hashlist; /* BT_TYPE_BUSY */
157	} bt_u;
158#define	bt_hashlist	bt_u.u_hashlist
159#define	bt_freelist	bt_u.u_freelist
160	vmem_addr_t	bt_start;
161	vmem_size_t	bt_size;
162	int		bt_type;
163};
164
165#define	BT_TYPE_SPAN		1	/* Allocated from importfn */
166#define	BT_TYPE_SPAN_STATIC	2	/* vmem_add() or create. */
167#define	BT_TYPE_FREE		3	/* Available space. */
168#define	BT_TYPE_BUSY		4	/* Used space. */
169#define	BT_ISSPAN_P(bt)	((bt)->bt_type <= BT_TYPE_SPAN_STATIC)
170
171#define	BT_END(bt)	((bt)->bt_start + (bt)->bt_size - 1)
172
173#if defined(DIAGNOSTIC)
174static int enable_vmem_check = 1;
175SYSCTL_INT(_debug, OID_AUTO, vmem_check, CTLFLAG_RWTUN,
176    &enable_vmem_check, 0, "Enable vmem check");
177static void vmem_check(vmem_t *);
178#endif
179
180static struct callout	vmem_periodic_ch;
181static int		vmem_periodic_interval;
182static struct task	vmem_periodic_wk;
183
184static struct mtx_padalign vmem_list_lock;
185static LIST_HEAD(, vmem) vmem_list = LIST_HEAD_INITIALIZER(vmem_list);
186
187/* ---- misc */
188#define	VMEM_CONDVAR_INIT(vm, wchan)	cv_init(&vm->vm_cv, wchan)
189#define	VMEM_CONDVAR_DESTROY(vm)	cv_destroy(&vm->vm_cv)
190#define	VMEM_CONDVAR_WAIT(vm)		cv_wait(&vm->vm_cv, &vm->vm_lock)
191#define	VMEM_CONDVAR_BROADCAST(vm)	cv_broadcast(&vm->vm_cv)
192
193
194#define	VMEM_LOCK(vm)		mtx_lock(&vm->vm_lock)
195#define	VMEM_TRYLOCK(vm)	mtx_trylock(&vm->vm_lock)
196#define	VMEM_UNLOCK(vm)		mtx_unlock(&vm->vm_lock)
197#define	VMEM_LOCK_INIT(vm, name) mtx_init(&vm->vm_lock, (name), NULL, MTX_DEF)
198#define	VMEM_LOCK_DESTROY(vm)	mtx_destroy(&vm->vm_lock)
199#define	VMEM_ASSERT_LOCKED(vm)	mtx_assert(&vm->vm_lock, MA_OWNED);
200
201#define	VMEM_ALIGNUP(addr, align)	(-(-(addr) & -(align)))
202
203#define	VMEM_CROSS_P(addr1, addr2, boundary) \
204	((((addr1) ^ (addr2)) & -(boundary)) != 0)
205
206#define	ORDER2SIZE(order)	((order) < VMEM_OPTVALUE ? ((order) + 1) : \
207    (vmem_size_t)1 << ((order) - (VMEM_OPTVALUE - VMEM_OPTORDER - 1)))
208#define	SIZE2ORDER(size)	((size) <= VMEM_OPTVALUE ? ((size) - 1) : \
209    (flsl(size) + (VMEM_OPTVALUE - VMEM_OPTORDER - 2)))
210
211/*
212 * Maximum number of boundary tags that may be required to satisfy an
213 * allocation.  Two may be required to import.  Another two may be
214 * required to clip edges.
215 */
216#define	BT_MAXALLOC	4
217
218/*
219 * Max free limits the number of locally cached boundary tags.  We
220 * just want to avoid hitting the zone allocator for every call.
221 */
222#define BT_MAXFREE	(BT_MAXALLOC * 8)
223
224/* Allocator for boundary tags. */
225static uma_zone_t vmem_bt_zone;
226
227/* boot time arena storage. */
228static struct vmem kernel_arena_storage;
229static struct vmem kmem_arena_storage;
230static struct vmem buffer_arena_storage;
231static struct vmem transient_arena_storage;
232vmem_t *kernel_arena = &kernel_arena_storage;
233vmem_t *kmem_arena = &kmem_arena_storage;
234vmem_t *buffer_arena = &buffer_arena_storage;
235vmem_t *transient_arena = &transient_arena_storage;
236
237#ifdef DEBUG_MEMGUARD
238static struct vmem memguard_arena_storage;
239vmem_t *memguard_arena = &memguard_arena_storage;
240#endif
241
242/*
243 * Fill the vmem's boundary tag cache.  We guarantee that boundary tag
244 * allocation will not fail once bt_fill() passes.  To do so we cache
245 * at least the maximum possible tag allocations in the arena.
246 */
247static int
248bt_fill(vmem_t *vm, int flags)
249{
250	bt_t *bt;
251
252	VMEM_ASSERT_LOCKED(vm);
253
254	/*
255	 * Only allow the kmem arena to dip into reserve tags.  It is the
256	 * vmem where new tags come from.
257	 */
258	flags &= BT_FLAGS;
259	if (vm != kmem_arena)
260		flags &= ~M_USE_RESERVE;
261
262	/*
263	 * Loop until we meet the reserve.  To minimize the lock shuffle
264	 * and prevent simultaneous fills we first try a NOWAIT regardless
265	 * of the caller's flags.  Specify M_NOVM so we don't recurse while
266	 * holding a vmem lock.
267	 */
268	while (vm->vm_nfreetags < BT_MAXALLOC) {
269		bt = uma_zalloc(vmem_bt_zone,
270		    (flags & M_USE_RESERVE) | M_NOWAIT | M_NOVM);
271		if (bt == NULL) {
272			VMEM_UNLOCK(vm);
273			bt = uma_zalloc(vmem_bt_zone, flags);
274			VMEM_LOCK(vm);
275			if (bt == NULL && (flags & M_NOWAIT) != 0)
276				break;
277		}
278		LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
279		vm->vm_nfreetags++;
280	}
281
282	if (vm->vm_nfreetags < BT_MAXALLOC)
283		return ENOMEM;
284
285	return 0;
286}
287
288/*
289 * Pop a tag off of the freetag stack.
290 */
291static bt_t *
292bt_alloc(vmem_t *vm)
293{
294	bt_t *bt;
295
296	VMEM_ASSERT_LOCKED(vm);
297	bt = LIST_FIRST(&vm->vm_freetags);
298	MPASS(bt != NULL);
299	LIST_REMOVE(bt, bt_freelist);
300	vm->vm_nfreetags--;
301
302	return bt;
303}
304
305/*
306 * Trim the per-vmem free list.  Returns with the lock released to
307 * avoid allocator recursions.
308 */
309static void
310bt_freetrim(vmem_t *vm, int freelimit)
311{
312	LIST_HEAD(, vmem_btag) freetags;
313	bt_t *bt;
314
315	LIST_INIT(&freetags);
316	VMEM_ASSERT_LOCKED(vm);
317	while (vm->vm_nfreetags > freelimit) {
318		bt = LIST_FIRST(&vm->vm_freetags);
319		LIST_REMOVE(bt, bt_freelist);
320		vm->vm_nfreetags--;
321		LIST_INSERT_HEAD(&freetags, bt, bt_freelist);
322	}
323	VMEM_UNLOCK(vm);
324	while ((bt = LIST_FIRST(&freetags)) != NULL) {
325		LIST_REMOVE(bt, bt_freelist);
326		uma_zfree(vmem_bt_zone, bt);
327	}
328}
329
330static inline void
331bt_free(vmem_t *vm, bt_t *bt)
332{
333
334	VMEM_ASSERT_LOCKED(vm);
335	MPASS(LIST_FIRST(&vm->vm_freetags) != bt);
336	LIST_INSERT_HEAD(&vm->vm_freetags, bt, bt_freelist);
337	vm->vm_nfreetags++;
338}
339
340/*
341 * freelist[0] ... [1, 1]
342 * freelist[1] ... [2, 2]
343 *  :
344 * freelist[29] ... [30, 30]
345 * freelist[30] ... [31, 31]
346 * freelist[31] ... [32, 63]
347 * freelist[33] ... [64, 127]
348 *  :
349 * freelist[n] ... [(1 << (n - 26)), (1 << (n - 25)) - 1]
350 *  :
351 */
352
353static struct vmem_freelist *
354bt_freehead_tofree(vmem_t *vm, vmem_size_t size)
355{
356	const vmem_size_t qsize = size >> vm->vm_quantum_shift;
357	const int idx = SIZE2ORDER(qsize);
358
359	MPASS(size != 0 && qsize != 0);
360	MPASS((size & vm->vm_quantum_mask) == 0);
361	MPASS(idx >= 0);
362	MPASS(idx < VMEM_MAXORDER);
363
364	return &vm->vm_freelist[idx];
365}
366
367/*
368 * bt_freehead_toalloc: return the freelist for the given size and allocation
369 * strategy.
370 *
371 * For M_FIRSTFIT, return the list in which any blocks are large enough
372 * for the requested size.  otherwise, return the list which can have blocks
373 * large enough for the requested size.
374 */
375static struct vmem_freelist *
376bt_freehead_toalloc(vmem_t *vm, vmem_size_t size, int strat)
377{
378	const vmem_size_t qsize = size >> vm->vm_quantum_shift;
379	int idx = SIZE2ORDER(qsize);
380
381	MPASS(size != 0 && qsize != 0);
382	MPASS((size & vm->vm_quantum_mask) == 0);
383
384	if (strat == M_FIRSTFIT && ORDER2SIZE(idx) != qsize) {
385		idx++;
386		/* check too large request? */
387	}
388	MPASS(idx >= 0);
389	MPASS(idx < VMEM_MAXORDER);
390
391	return &vm->vm_freelist[idx];
392}
393
394/* ---- boundary tag hash */
395
396static struct vmem_hashlist *
397bt_hashhead(vmem_t *vm, vmem_addr_t addr)
398{
399	struct vmem_hashlist *list;
400	unsigned int hash;
401
402	hash = hash32_buf(&addr, sizeof(addr), 0);
403	list = &vm->vm_hashlist[hash % vm->vm_hashsize];
404
405	return list;
406}
407
408static bt_t *
409bt_lookupbusy(vmem_t *vm, vmem_addr_t addr)
410{
411	struct vmem_hashlist *list;
412	bt_t *bt;
413
414	VMEM_ASSERT_LOCKED(vm);
415	list = bt_hashhead(vm, addr);
416	LIST_FOREACH(bt, list, bt_hashlist) {
417		if (bt->bt_start == addr) {
418			break;
419		}
420	}
421
422	return bt;
423}
424
425static void
426bt_rembusy(vmem_t *vm, bt_t *bt)
427{
428
429	VMEM_ASSERT_LOCKED(vm);
430	MPASS(vm->vm_nbusytag > 0);
431	vm->vm_inuse -= bt->bt_size;
432	vm->vm_nbusytag--;
433	LIST_REMOVE(bt, bt_hashlist);
434}
435
436static void
437bt_insbusy(vmem_t *vm, bt_t *bt)
438{
439	struct vmem_hashlist *list;
440
441	VMEM_ASSERT_LOCKED(vm);
442	MPASS(bt->bt_type == BT_TYPE_BUSY);
443
444	list = bt_hashhead(vm, bt->bt_start);
445	LIST_INSERT_HEAD(list, bt, bt_hashlist);
446	vm->vm_nbusytag++;
447	vm->vm_inuse += bt->bt_size;
448}
449
450/* ---- boundary tag list */
451
452static void
453bt_remseg(vmem_t *vm, bt_t *bt)
454{
455
456	TAILQ_REMOVE(&vm->vm_seglist, bt, bt_seglist);
457	bt_free(vm, bt);
458}
459
460static void
461bt_insseg(vmem_t *vm, bt_t *bt, bt_t *prev)
462{
463
464	TAILQ_INSERT_AFTER(&vm->vm_seglist, prev, bt, bt_seglist);
465}
466
467static void
468bt_insseg_tail(vmem_t *vm, bt_t *bt)
469{
470
471	TAILQ_INSERT_TAIL(&vm->vm_seglist, bt, bt_seglist);
472}
473
474static void
475bt_remfree(vmem_t *vm, bt_t *bt)
476{
477
478	MPASS(bt->bt_type == BT_TYPE_FREE);
479
480	LIST_REMOVE(bt, bt_freelist);
481}
482
483static void
484bt_insfree(vmem_t *vm, bt_t *bt)
485{
486	struct vmem_freelist *list;
487
488	list = bt_freehead_tofree(vm, bt->bt_size);
489	LIST_INSERT_HEAD(list, bt, bt_freelist);
490}
491
492/* ---- vmem internal functions */
493
494/*
495 * Import from the arena into the quantum cache in UMA.
496 */
497static int
498qc_import(void *arg, void **store, int cnt, int flags)
499{
500	qcache_t *qc;
501	vmem_addr_t addr;
502	int i;
503
504	qc = arg;
505	if ((flags & VMEM_FITMASK) == 0)
506		flags |= M_BESTFIT;
507	for (i = 0; i < cnt; i++) {
508		if (vmem_xalloc(qc->qc_vmem, qc->qc_size, 0, 0, 0,
509		    VMEM_ADDR_MIN, VMEM_ADDR_MAX, flags, &addr) != 0)
510			break;
511		store[i] = (void *)addr;
512		/* Only guarantee one allocation. */
513		flags &= ~M_WAITOK;
514		flags |= M_NOWAIT;
515	}
516	return i;
517}
518
519/*
520 * Release memory from the UMA cache to the arena.
521 */
522static void
523qc_release(void *arg, void **store, int cnt)
524{
525	qcache_t *qc;
526	int i;
527
528	qc = arg;
529	for (i = 0; i < cnt; i++)
530		vmem_xfree(qc->qc_vmem, (vmem_addr_t)store[i], qc->qc_size);
531}
532
533static void
534qc_init(vmem_t *vm, vmem_size_t qcache_max)
535{
536	qcache_t *qc;
537	vmem_size_t size;
538	int qcache_idx_max;
539	int i;
540
541	MPASS((qcache_max & vm->vm_quantum_mask) == 0);
542	qcache_idx_max = MIN(qcache_max >> vm->vm_quantum_shift,
543	    VMEM_QCACHE_IDX_MAX);
544	vm->vm_qcache_max = qcache_idx_max << vm->vm_quantum_shift;
545	for (i = 0; i < qcache_idx_max; i++) {
546		qc = &vm->vm_qcache[i];
547		size = (i + 1) << vm->vm_quantum_shift;
548		snprintf(qc->qc_name, sizeof(qc->qc_name), "%s-%zu",
549		    vm->vm_name, size);
550		qc->qc_vmem = vm;
551		qc->qc_size = size;
552		qc->qc_cache = uma_zcache_create(qc->qc_name, size,
553		    NULL, NULL, NULL, NULL, qc_import, qc_release, qc,
554		    UMA_ZONE_VM);
555		MPASS(qc->qc_cache);
556	}
557}
558
559static void
560qc_destroy(vmem_t *vm)
561{
562	int qcache_idx_max;
563	int i;
564
565	qcache_idx_max = vm->vm_qcache_max >> vm->vm_quantum_shift;
566	for (i = 0; i < qcache_idx_max; i++)
567		uma_zdestroy(vm->vm_qcache[i].qc_cache);
568}
569
570static void
571qc_drain(vmem_t *vm)
572{
573	int qcache_idx_max;
574	int i;
575
576	qcache_idx_max = vm->vm_qcache_max >> vm->vm_quantum_shift;
577	for (i = 0; i < qcache_idx_max; i++)
578		zone_drain(vm->vm_qcache[i].qc_cache);
579}
580
581#ifndef UMA_MD_SMALL_ALLOC
582
583static struct mtx_padalign vmem_bt_lock;
584
585/*
586 * vmem_bt_alloc:  Allocate a new page of boundary tags.
587 *
588 * On architectures with uma_small_alloc there is no recursion; no address
589 * space need be allocated to allocate boundary tags.  For the others, we
590 * must handle recursion.  Boundary tags are necessary to allocate new
591 * boundary tags.
592 *
593 * UMA guarantees that enough tags are held in reserve to allocate a new
594 * page of kva.  We dip into this reserve by specifying M_USE_RESERVE only
595 * when allocating the page to hold new boundary tags.  In this way the
596 * reserve is automatically filled by the allocation that uses the reserve.
597 *
598 * We still have to guarantee that the new tags are allocated atomically since
599 * many threads may try concurrently.  The bt_lock provides this guarantee.
600 * We convert WAITOK allocations to NOWAIT and then handle the blocking here
601 * on failure.  It's ok to return NULL for a WAITOK allocation as UMA will
602 * loop again after checking to see if we lost the race to allocate.
603 *
604 * There is a small race between vmem_bt_alloc() returning the page and the
605 * zone lock being acquired to add the page to the zone.  For WAITOK
606 * allocations we just pause briefly.  NOWAIT may experience a transient
607 * failure.  To alleviate this we permit a small number of simultaneous
608 * fills to proceed concurrently so NOWAIT is less likely to fail unless
609 * we are really out of KVA.
610 */
611static void *
612vmem_bt_alloc(uma_zone_t zone, vm_size_t bytes, uint8_t *pflag, int wait)
613{
614	vmem_addr_t addr;
615
616	*pflag = UMA_SLAB_KMEM;
617
618	/*
619	 * Single thread boundary tag allocation so that the address space
620	 * and memory are added in one atomic operation.
621	 */
622	mtx_lock(&vmem_bt_lock);
623	if (vmem_xalloc(kmem_arena, bytes, 0, 0, 0, VMEM_ADDR_MIN,
624	    VMEM_ADDR_MAX, M_NOWAIT | M_NOVM | M_USE_RESERVE | M_BESTFIT,
625	    &addr) == 0) {
626		if (kmem_back(kmem_object, addr, bytes,
627		    M_NOWAIT | M_USE_RESERVE) == 0) {
628			mtx_unlock(&vmem_bt_lock);
629			return ((void *)addr);
630		}
631		vmem_xfree(kmem_arena, addr, bytes);
632		mtx_unlock(&vmem_bt_lock);
633		/*
634		 * Out of memory, not address space.  This may not even be
635		 * possible due to M_USE_RESERVE page allocation.
636		 */
637		if (wait & M_WAITOK)
638			VM_WAIT;
639		return (NULL);
640	}
641	mtx_unlock(&vmem_bt_lock);
642	/*
643	 * We're either out of address space or lost a fill race.
644	 */
645	if (wait & M_WAITOK)
646		pause("btalloc", 1);
647
648	return (NULL);
649}
650#endif
651
652void
653vmem_startup(void)
654{
655
656	mtx_init(&vmem_list_lock, "vmem list lock", NULL, MTX_DEF);
657	vmem_bt_zone = uma_zcreate("vmem btag",
658	    sizeof(struct vmem_btag), NULL, NULL, NULL, NULL,
659	    UMA_ALIGN_PTR, UMA_ZONE_VM);
660#ifndef UMA_MD_SMALL_ALLOC
661	mtx_init(&vmem_bt_lock, "btag lock", NULL, MTX_DEF);
662	uma_prealloc(vmem_bt_zone, BT_MAXALLOC);
663	/*
664	 * Reserve enough tags to allocate new tags.  We allow multiple
665	 * CPUs to attempt to allocate new tags concurrently to limit
666	 * false restarts in UMA.
667	 */
668	uma_zone_reserve(vmem_bt_zone, BT_MAXALLOC * (mp_ncpus + 1) / 2);
669	uma_zone_set_allocf(vmem_bt_zone, vmem_bt_alloc);
670#endif
671}
672
673/* ---- rehash */
674
675static int
676vmem_rehash(vmem_t *vm, vmem_size_t newhashsize)
677{
678	bt_t *bt;
679	int i;
680	struct vmem_hashlist *newhashlist;
681	struct vmem_hashlist *oldhashlist;
682	vmem_size_t oldhashsize;
683
684	MPASS(newhashsize > 0);
685
686	newhashlist = malloc(sizeof(struct vmem_hashlist) * newhashsize,
687	    M_VMEM, M_NOWAIT);
688	if (newhashlist == NULL)
689		return ENOMEM;
690	for (i = 0; i < newhashsize; i++) {
691		LIST_INIT(&newhashlist[i]);
692	}
693
694	VMEM_LOCK(vm);
695	oldhashlist = vm->vm_hashlist;
696	oldhashsize = vm->vm_hashsize;
697	vm->vm_hashlist = newhashlist;
698	vm->vm_hashsize = newhashsize;
699	if (oldhashlist == NULL) {
700		VMEM_UNLOCK(vm);
701		return 0;
702	}
703	for (i = 0; i < oldhashsize; i++) {
704		while ((bt = LIST_FIRST(&oldhashlist[i])) != NULL) {
705			bt_rembusy(vm, bt);
706			bt_insbusy(vm, bt);
707		}
708	}
709	VMEM_UNLOCK(vm);
710
711	if (oldhashlist != vm->vm_hash0) {
712		free(oldhashlist, M_VMEM);
713	}
714
715	return 0;
716}
717
718static void
719vmem_periodic_kick(void *dummy)
720{
721
722	taskqueue_enqueue(taskqueue_thread, &vmem_periodic_wk);
723}
724
725static void
726vmem_periodic(void *unused, int pending)
727{
728	vmem_t *vm;
729	vmem_size_t desired;
730	vmem_size_t current;
731
732	mtx_lock(&vmem_list_lock);
733	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
734#ifdef DIAGNOSTIC
735		/* Convenient time to verify vmem state. */
736		if (enable_vmem_check == 1) {
737			VMEM_LOCK(vm);
738			vmem_check(vm);
739			VMEM_UNLOCK(vm);
740		}
741#endif
742		desired = 1 << flsl(vm->vm_nbusytag);
743		desired = MIN(MAX(desired, VMEM_HASHSIZE_MIN),
744		    VMEM_HASHSIZE_MAX);
745		current = vm->vm_hashsize;
746
747		/* Grow in powers of two.  Shrink less aggressively. */
748		if (desired >= current * 2 || desired * 4 <= current)
749			vmem_rehash(vm, desired);
750
751		/*
752		 * Periodically wake up threads waiting for resources,
753		 * so they could ask for reclamation again.
754		 */
755		VMEM_CONDVAR_BROADCAST(vm);
756	}
757	mtx_unlock(&vmem_list_lock);
758
759	callout_reset(&vmem_periodic_ch, vmem_periodic_interval,
760	    vmem_periodic_kick, NULL);
761}
762
763static void
764vmem_start_callout(void *unused)
765{
766
767	TASK_INIT(&vmem_periodic_wk, 0, vmem_periodic, NULL);
768	vmem_periodic_interval = hz * 10;
769	callout_init(&vmem_periodic_ch, CALLOUT_MPSAFE);
770	callout_reset(&vmem_periodic_ch, vmem_periodic_interval,
771	    vmem_periodic_kick, NULL);
772}
773SYSINIT(vfs, SI_SUB_CONFIGURE, SI_ORDER_ANY, vmem_start_callout, NULL);
774
775static void
776vmem_add1(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, int type)
777{
778	bt_t *btspan;
779	bt_t *btfree;
780
781	MPASS(type == BT_TYPE_SPAN || type == BT_TYPE_SPAN_STATIC);
782	MPASS((size & vm->vm_quantum_mask) == 0);
783
784	btspan = bt_alloc(vm);
785	btspan->bt_type = type;
786	btspan->bt_start = addr;
787	btspan->bt_size = size;
788	bt_insseg_tail(vm, btspan);
789
790	btfree = bt_alloc(vm);
791	btfree->bt_type = BT_TYPE_FREE;
792	btfree->bt_start = addr;
793	btfree->bt_size = size;
794	bt_insseg(vm, btfree, btspan);
795	bt_insfree(vm, btfree);
796
797	vm->vm_size += size;
798}
799
800static void
801vmem_destroy1(vmem_t *vm)
802{
803	bt_t *bt;
804
805	/*
806	 * Drain per-cpu quantum caches.
807	 */
808	qc_destroy(vm);
809
810	/*
811	 * The vmem should now only contain empty segments.
812	 */
813	VMEM_LOCK(vm);
814	MPASS(vm->vm_nbusytag == 0);
815
816	while ((bt = TAILQ_FIRST(&vm->vm_seglist)) != NULL)
817		bt_remseg(vm, bt);
818
819	if (vm->vm_hashlist != NULL && vm->vm_hashlist != vm->vm_hash0)
820		free(vm->vm_hashlist, M_VMEM);
821
822	bt_freetrim(vm, 0);
823
824	VMEM_CONDVAR_DESTROY(vm);
825	VMEM_LOCK_DESTROY(vm);
826	free(vm, M_VMEM);
827}
828
829static int
830vmem_import(vmem_t *vm, vmem_size_t size, vmem_size_t align, int flags)
831{
832	vmem_addr_t addr;
833	int error;
834
835	if (vm->vm_importfn == NULL)
836		return EINVAL;
837
838	/*
839	 * To make sure we get a span that meets the alignment we double it
840	 * and add the size to the tail.  This slightly overestimates.
841	 */
842	if (align != vm->vm_quantum_mask + 1)
843		size = (align * 2) + size;
844	size = roundup(size, vm->vm_import_quantum);
845
846	/*
847	 * Hide MAXALLOC tags so we're guaranteed to be able to add this
848	 * span and the tag we want to allocate from it.
849	 */
850	MPASS(vm->vm_nfreetags >= BT_MAXALLOC);
851	vm->vm_nfreetags -= BT_MAXALLOC;
852	VMEM_UNLOCK(vm);
853	error = (vm->vm_importfn)(vm->vm_arg, size, flags, &addr);
854	VMEM_LOCK(vm);
855	vm->vm_nfreetags += BT_MAXALLOC;
856	if (error)
857		return ENOMEM;
858
859	vmem_add1(vm, addr, size, BT_TYPE_SPAN);
860
861	return 0;
862}
863
864/*
865 * vmem_fit: check if a bt can satisfy the given restrictions.
866 *
867 * it's a caller's responsibility to ensure the region is big enough
868 * before calling us.
869 */
870static int
871vmem_fit(const bt_t *bt, vmem_size_t size, vmem_size_t align,
872    vmem_size_t phase, vmem_size_t nocross, vmem_addr_t minaddr,
873    vmem_addr_t maxaddr, vmem_addr_t *addrp)
874{
875	vmem_addr_t start;
876	vmem_addr_t end;
877
878	MPASS(size > 0);
879	MPASS(bt->bt_size >= size); /* caller's responsibility */
880
881	/*
882	 * XXX assumption: vmem_addr_t and vmem_size_t are
883	 * unsigned integer of the same size.
884	 */
885
886	start = bt->bt_start;
887	if (start < minaddr) {
888		start = minaddr;
889	}
890	end = BT_END(bt);
891	if (end > maxaddr)
892		end = maxaddr;
893	if (start > end)
894		return (ENOMEM);
895
896	start = VMEM_ALIGNUP(start - phase, align) + phase;
897	if (start < bt->bt_start)
898		start += align;
899	if (VMEM_CROSS_P(start, start + size - 1, nocross)) {
900		MPASS(align < nocross);
901		start = VMEM_ALIGNUP(start - phase, nocross) + phase;
902	}
903	if (start <= end && end - start >= size - 1) {
904		MPASS((start & (align - 1)) == phase);
905		MPASS(!VMEM_CROSS_P(start, start + size - 1, nocross));
906		MPASS(minaddr <= start);
907		MPASS(maxaddr == 0 || start + size - 1 <= maxaddr);
908		MPASS(bt->bt_start <= start);
909		MPASS(BT_END(bt) - start >= size - 1);
910		*addrp = start;
911
912		return (0);
913	}
914	return (ENOMEM);
915}
916
917/*
918 * vmem_clip:  Trim the boundary tag edges to the requested start and size.
919 */
920static void
921vmem_clip(vmem_t *vm, bt_t *bt, vmem_addr_t start, vmem_size_t size)
922{
923	bt_t *btnew;
924	bt_t *btprev;
925
926	VMEM_ASSERT_LOCKED(vm);
927	MPASS(bt->bt_type == BT_TYPE_FREE);
928	MPASS(bt->bt_size >= size);
929	bt_remfree(vm, bt);
930	if (bt->bt_start != start) {
931		btprev = bt_alloc(vm);
932		btprev->bt_type = BT_TYPE_FREE;
933		btprev->bt_start = bt->bt_start;
934		btprev->bt_size = start - bt->bt_start;
935		bt->bt_start = start;
936		bt->bt_size -= btprev->bt_size;
937		bt_insfree(vm, btprev);
938		bt_insseg(vm, btprev,
939		    TAILQ_PREV(bt, vmem_seglist, bt_seglist));
940	}
941	MPASS(bt->bt_start == start);
942	if (bt->bt_size != size && bt->bt_size - size > vm->vm_quantum_mask) {
943		/* split */
944		btnew = bt_alloc(vm);
945		btnew->bt_type = BT_TYPE_BUSY;
946		btnew->bt_start = bt->bt_start;
947		btnew->bt_size = size;
948		bt->bt_start = bt->bt_start + size;
949		bt->bt_size -= size;
950		bt_insfree(vm, bt);
951		bt_insseg(vm, btnew,
952		    TAILQ_PREV(bt, vmem_seglist, bt_seglist));
953		bt_insbusy(vm, btnew);
954		bt = btnew;
955	} else {
956		bt->bt_type = BT_TYPE_BUSY;
957		bt_insbusy(vm, bt);
958	}
959	MPASS(bt->bt_size >= size);
960	bt->bt_type = BT_TYPE_BUSY;
961}
962
963/* ---- vmem API */
964
965void
966vmem_set_import(vmem_t *vm, vmem_import_t *importfn,
967     vmem_release_t *releasefn, void *arg, vmem_size_t import_quantum)
968{
969
970	VMEM_LOCK(vm);
971	vm->vm_importfn = importfn;
972	vm->vm_releasefn = releasefn;
973	vm->vm_arg = arg;
974	vm->vm_import_quantum = import_quantum;
975	VMEM_UNLOCK(vm);
976}
977
978void
979vmem_set_reclaim(vmem_t *vm, vmem_reclaim_t *reclaimfn)
980{
981
982	VMEM_LOCK(vm);
983	vm->vm_reclaimfn = reclaimfn;
984	VMEM_UNLOCK(vm);
985}
986
987/*
988 * vmem_init: Initializes vmem arena.
989 */
990vmem_t *
991vmem_init(vmem_t *vm, const char *name, vmem_addr_t base, vmem_size_t size,
992    vmem_size_t quantum, vmem_size_t qcache_max, int flags)
993{
994	int i;
995
996	MPASS(quantum > 0);
997	MPASS((quantum & (quantum - 1)) == 0);
998
999	bzero(vm, sizeof(*vm));
1000
1001	VMEM_CONDVAR_INIT(vm, name);
1002	VMEM_LOCK_INIT(vm, name);
1003	vm->vm_nfreetags = 0;
1004	LIST_INIT(&vm->vm_freetags);
1005	strlcpy(vm->vm_name, name, sizeof(vm->vm_name));
1006	vm->vm_quantum_mask = quantum - 1;
1007	vm->vm_quantum_shift = flsl(quantum) - 1;
1008	vm->vm_nbusytag = 0;
1009	vm->vm_size = 0;
1010	vm->vm_inuse = 0;
1011	qc_init(vm, qcache_max);
1012
1013	TAILQ_INIT(&vm->vm_seglist);
1014	for (i = 0; i < VMEM_MAXORDER; i++) {
1015		LIST_INIT(&vm->vm_freelist[i]);
1016	}
1017	memset(&vm->vm_hash0, 0, sizeof(vm->vm_hash0));
1018	vm->vm_hashsize = VMEM_HASHSIZE_MIN;
1019	vm->vm_hashlist = vm->vm_hash0;
1020
1021	if (size != 0) {
1022		if (vmem_add(vm, base, size, flags) != 0) {
1023			vmem_destroy1(vm);
1024			return NULL;
1025		}
1026	}
1027
1028	mtx_lock(&vmem_list_lock);
1029	LIST_INSERT_HEAD(&vmem_list, vm, vm_alllist);
1030	mtx_unlock(&vmem_list_lock);
1031
1032	return vm;
1033}
1034
1035/*
1036 * vmem_create: create an arena.
1037 */
1038vmem_t *
1039vmem_create(const char *name, vmem_addr_t base, vmem_size_t size,
1040    vmem_size_t quantum, vmem_size_t qcache_max, int flags)
1041{
1042
1043	vmem_t *vm;
1044
1045	vm = malloc(sizeof(*vm), M_VMEM, flags & (M_WAITOK|M_NOWAIT));
1046	if (vm == NULL)
1047		return (NULL);
1048	if (vmem_init(vm, name, base, size, quantum, qcache_max,
1049	    flags) == NULL) {
1050		free(vm, M_VMEM);
1051		return (NULL);
1052	}
1053	return (vm);
1054}
1055
1056void
1057vmem_destroy(vmem_t *vm)
1058{
1059
1060	mtx_lock(&vmem_list_lock);
1061	LIST_REMOVE(vm, vm_alllist);
1062	mtx_unlock(&vmem_list_lock);
1063
1064	vmem_destroy1(vm);
1065}
1066
1067vmem_size_t
1068vmem_roundup_size(vmem_t *vm, vmem_size_t size)
1069{
1070
1071	return (size + vm->vm_quantum_mask) & ~vm->vm_quantum_mask;
1072}
1073
1074/*
1075 * vmem_alloc: allocate resource from the arena.
1076 */
1077int
1078vmem_alloc(vmem_t *vm, vmem_size_t size, int flags, vmem_addr_t *addrp)
1079{
1080	const int strat __unused = flags & VMEM_FITMASK;
1081	qcache_t *qc;
1082
1083	flags &= VMEM_FLAGS;
1084	MPASS(size > 0);
1085	MPASS(strat == M_BESTFIT || strat == M_FIRSTFIT);
1086	if ((flags & M_NOWAIT) == 0)
1087		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "vmem_alloc");
1088
1089	if (size <= vm->vm_qcache_max) {
1090		qc = &vm->vm_qcache[(size - 1) >> vm->vm_quantum_shift];
1091		*addrp = (vmem_addr_t)uma_zalloc(qc->qc_cache, flags);
1092		if (*addrp == 0)
1093			return (ENOMEM);
1094		return (0);
1095	}
1096
1097	return vmem_xalloc(vm, size, 0, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX,
1098	    flags, addrp);
1099}
1100
1101int
1102vmem_xalloc(vmem_t *vm, const vmem_size_t size0, vmem_size_t align,
1103    const vmem_size_t phase, const vmem_size_t nocross,
1104    const vmem_addr_t minaddr, const vmem_addr_t maxaddr, int flags,
1105    vmem_addr_t *addrp)
1106{
1107	const vmem_size_t size = vmem_roundup_size(vm, size0);
1108	struct vmem_freelist *list;
1109	struct vmem_freelist *first;
1110	struct vmem_freelist *end;
1111	vmem_size_t avail;
1112	bt_t *bt;
1113	int error;
1114	int strat;
1115
1116	flags &= VMEM_FLAGS;
1117	strat = flags & VMEM_FITMASK;
1118	MPASS(size0 > 0);
1119	MPASS(size > 0);
1120	MPASS(strat == M_BESTFIT || strat == M_FIRSTFIT);
1121	MPASS((flags & (M_NOWAIT|M_WAITOK)) != (M_NOWAIT|M_WAITOK));
1122	if ((flags & M_NOWAIT) == 0)
1123		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "vmem_xalloc");
1124	MPASS((align & vm->vm_quantum_mask) == 0);
1125	MPASS((align & (align - 1)) == 0);
1126	MPASS((phase & vm->vm_quantum_mask) == 0);
1127	MPASS((nocross & vm->vm_quantum_mask) == 0);
1128	MPASS((nocross & (nocross - 1)) == 0);
1129	MPASS((align == 0 && phase == 0) || phase < align);
1130	MPASS(nocross == 0 || nocross >= size);
1131	MPASS(minaddr <= maxaddr);
1132	MPASS(!VMEM_CROSS_P(phase, phase + size - 1, nocross));
1133
1134	if (align == 0)
1135		align = vm->vm_quantum_mask + 1;
1136
1137	*addrp = 0;
1138	end = &vm->vm_freelist[VMEM_MAXORDER];
1139	/*
1140	 * choose a free block from which we allocate.
1141	 */
1142	first = bt_freehead_toalloc(vm, size, strat);
1143	VMEM_LOCK(vm);
1144	for (;;) {
1145		/*
1146		 * Make sure we have enough tags to complete the
1147		 * operation.
1148		 */
1149		if (vm->vm_nfreetags < BT_MAXALLOC &&
1150		    bt_fill(vm, flags) != 0) {
1151			error = ENOMEM;
1152			break;
1153		}
1154		/*
1155	 	 * Scan freelists looking for a tag that satisfies the
1156		 * allocation.  If we're doing BESTFIT we may encounter
1157		 * sizes below the request.  If we're doing FIRSTFIT we
1158		 * inspect only the first element from each list.
1159		 */
1160		for (list = first; list < end; list++) {
1161			LIST_FOREACH(bt, list, bt_freelist) {
1162				if (bt->bt_size >= size) {
1163					error = vmem_fit(bt, size, align, phase,
1164					    nocross, minaddr, maxaddr, addrp);
1165					if (error == 0) {
1166						vmem_clip(vm, bt, *addrp, size);
1167						goto out;
1168					}
1169				}
1170				/* FIRST skips to the next list. */
1171				if (strat == M_FIRSTFIT)
1172					break;
1173			}
1174		}
1175		/*
1176		 * Retry if the fast algorithm failed.
1177		 */
1178		if (strat == M_FIRSTFIT) {
1179			strat = M_BESTFIT;
1180			first = bt_freehead_toalloc(vm, size, strat);
1181			continue;
1182		}
1183		/*
1184		 * XXX it is possible to fail to meet restrictions with the
1185		 * imported region.  It is up to the user to specify the
1186		 * import quantum such that it can satisfy any allocation.
1187		 */
1188		if (vmem_import(vm, size, align, flags) == 0)
1189			continue;
1190
1191		/*
1192		 * Try to free some space from the quantum cache or reclaim
1193		 * functions if available.
1194		 */
1195		if (vm->vm_qcache_max != 0 || vm->vm_reclaimfn != NULL) {
1196			avail = vm->vm_size - vm->vm_inuse;
1197			VMEM_UNLOCK(vm);
1198			if (vm->vm_qcache_max != 0)
1199				qc_drain(vm);
1200			if (vm->vm_reclaimfn != NULL)
1201				vm->vm_reclaimfn(vm, flags);
1202			VMEM_LOCK(vm);
1203			/* If we were successful retry even NOWAIT. */
1204			if (vm->vm_size - vm->vm_inuse > avail)
1205				continue;
1206		}
1207		if ((flags & M_NOWAIT) != 0) {
1208			error = ENOMEM;
1209			break;
1210		}
1211		VMEM_CONDVAR_WAIT(vm);
1212	}
1213out:
1214	VMEM_UNLOCK(vm);
1215	if (error != 0 && (flags & M_NOWAIT) == 0)
1216		panic("failed to allocate waiting allocation\n");
1217
1218	return (error);
1219}
1220
1221/*
1222 * vmem_free: free the resource to the arena.
1223 */
1224void
1225vmem_free(vmem_t *vm, vmem_addr_t addr, vmem_size_t size)
1226{
1227	qcache_t *qc;
1228	MPASS(size > 0);
1229
1230	if (size <= vm->vm_qcache_max) {
1231		qc = &vm->vm_qcache[(size - 1) >> vm->vm_quantum_shift];
1232		uma_zfree(qc->qc_cache, (void *)addr);
1233	} else
1234		vmem_xfree(vm, addr, size);
1235}
1236
1237void
1238vmem_xfree(vmem_t *vm, vmem_addr_t addr, vmem_size_t size)
1239{
1240	bt_t *bt;
1241	bt_t *t;
1242
1243	MPASS(size > 0);
1244
1245	VMEM_LOCK(vm);
1246	bt = bt_lookupbusy(vm, addr);
1247	MPASS(bt != NULL);
1248	MPASS(bt->bt_start == addr);
1249	MPASS(bt->bt_size == vmem_roundup_size(vm, size) ||
1250	    bt->bt_size - vmem_roundup_size(vm, size) <= vm->vm_quantum_mask);
1251	MPASS(bt->bt_type == BT_TYPE_BUSY);
1252	bt_rembusy(vm, bt);
1253	bt->bt_type = BT_TYPE_FREE;
1254
1255	/* coalesce */
1256	t = TAILQ_NEXT(bt, bt_seglist);
1257	if (t != NULL && t->bt_type == BT_TYPE_FREE) {
1258		MPASS(BT_END(bt) < t->bt_start);	/* YYY */
1259		bt->bt_size += t->bt_size;
1260		bt_remfree(vm, t);
1261		bt_remseg(vm, t);
1262	}
1263	t = TAILQ_PREV(bt, vmem_seglist, bt_seglist);
1264	if (t != NULL && t->bt_type == BT_TYPE_FREE) {
1265		MPASS(BT_END(t) < bt->bt_start);	/* YYY */
1266		bt->bt_size += t->bt_size;
1267		bt->bt_start = t->bt_start;
1268		bt_remfree(vm, t);
1269		bt_remseg(vm, t);
1270	}
1271
1272	t = TAILQ_PREV(bt, vmem_seglist, bt_seglist);
1273	MPASS(t != NULL);
1274	MPASS(BT_ISSPAN_P(t) || t->bt_type == BT_TYPE_BUSY);
1275	if (vm->vm_releasefn != NULL && t->bt_type == BT_TYPE_SPAN &&
1276	    t->bt_size == bt->bt_size) {
1277		vmem_addr_t spanaddr;
1278		vmem_size_t spansize;
1279
1280		MPASS(t->bt_start == bt->bt_start);
1281		spanaddr = bt->bt_start;
1282		spansize = bt->bt_size;
1283		bt_remseg(vm, bt);
1284		bt_remseg(vm, t);
1285		vm->vm_size -= spansize;
1286		VMEM_CONDVAR_BROADCAST(vm);
1287		bt_freetrim(vm, BT_MAXFREE);
1288		(*vm->vm_releasefn)(vm->vm_arg, spanaddr, spansize);
1289	} else {
1290		bt_insfree(vm, bt);
1291		VMEM_CONDVAR_BROADCAST(vm);
1292		bt_freetrim(vm, BT_MAXFREE);
1293	}
1294}
1295
1296/*
1297 * vmem_add:
1298 *
1299 */
1300int
1301vmem_add(vmem_t *vm, vmem_addr_t addr, vmem_size_t size, int flags)
1302{
1303	int error;
1304
1305	error = 0;
1306	flags &= VMEM_FLAGS;
1307	VMEM_LOCK(vm);
1308	if (vm->vm_nfreetags >= BT_MAXALLOC || bt_fill(vm, flags) == 0)
1309		vmem_add1(vm, addr, size, BT_TYPE_SPAN_STATIC);
1310	else
1311		error = ENOMEM;
1312	VMEM_UNLOCK(vm);
1313
1314	return (error);
1315}
1316
1317/*
1318 * vmem_size: information about arenas size
1319 */
1320vmem_size_t
1321vmem_size(vmem_t *vm, int typemask)
1322{
1323	int i;
1324
1325	switch (typemask) {
1326	case VMEM_ALLOC:
1327		return vm->vm_inuse;
1328	case VMEM_FREE:
1329		return vm->vm_size - vm->vm_inuse;
1330	case VMEM_FREE|VMEM_ALLOC:
1331		return vm->vm_size;
1332	case VMEM_MAXFREE:
1333		VMEM_LOCK(vm);
1334		for (i = VMEM_MAXORDER - 1; i >= 0; i--) {
1335			if (LIST_EMPTY(&vm->vm_freelist[i]))
1336				continue;
1337			VMEM_UNLOCK(vm);
1338			return ((vmem_size_t)ORDER2SIZE(i) <<
1339			    vm->vm_quantum_shift);
1340		}
1341		VMEM_UNLOCK(vm);
1342		return (0);
1343	default:
1344		panic("vmem_size");
1345	}
1346}
1347
1348/* ---- debug */
1349
1350#if defined(DDB) || defined(DIAGNOSTIC)
1351
1352static void bt_dump(const bt_t *, int (*)(const char *, ...)
1353    __printflike(1, 2));
1354
1355static const char *
1356bt_type_string(int type)
1357{
1358
1359	switch (type) {
1360	case BT_TYPE_BUSY:
1361		return "busy";
1362	case BT_TYPE_FREE:
1363		return "free";
1364	case BT_TYPE_SPAN:
1365		return "span";
1366	case BT_TYPE_SPAN_STATIC:
1367		return "static span";
1368	default:
1369		break;
1370	}
1371	return "BOGUS";
1372}
1373
1374static void
1375bt_dump(const bt_t *bt, int (*pr)(const char *, ...))
1376{
1377
1378	(*pr)("\t%p: %jx %jx, %d(%s)\n",
1379	    bt, (intmax_t)bt->bt_start, (intmax_t)bt->bt_size,
1380	    bt->bt_type, bt_type_string(bt->bt_type));
1381}
1382
1383static void
1384vmem_dump(const vmem_t *vm , int (*pr)(const char *, ...) __printflike(1, 2))
1385{
1386	const bt_t *bt;
1387	int i;
1388
1389	(*pr)("vmem %p '%s'\n", vm, vm->vm_name);
1390	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1391		bt_dump(bt, pr);
1392	}
1393
1394	for (i = 0; i < VMEM_MAXORDER; i++) {
1395		const struct vmem_freelist *fl = &vm->vm_freelist[i];
1396
1397		if (LIST_EMPTY(fl)) {
1398			continue;
1399		}
1400
1401		(*pr)("freelist[%d]\n", i);
1402		LIST_FOREACH(bt, fl, bt_freelist) {
1403			bt_dump(bt, pr);
1404		}
1405	}
1406}
1407
1408#endif /* defined(DDB) || defined(DIAGNOSTIC) */
1409
1410#if defined(DDB)
1411#include <ddb/ddb.h>
1412
1413static bt_t *
1414vmem_whatis_lookup(vmem_t *vm, vmem_addr_t addr)
1415{
1416	bt_t *bt;
1417
1418	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1419		if (BT_ISSPAN_P(bt)) {
1420			continue;
1421		}
1422		if (bt->bt_start <= addr && addr <= BT_END(bt)) {
1423			return bt;
1424		}
1425	}
1426
1427	return NULL;
1428}
1429
1430void
1431vmem_whatis(vmem_addr_t addr, int (*pr)(const char *, ...))
1432{
1433	vmem_t *vm;
1434
1435	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1436		bt_t *bt;
1437
1438		bt = vmem_whatis_lookup(vm, addr);
1439		if (bt == NULL) {
1440			continue;
1441		}
1442		(*pr)("%p is %p+%zu in VMEM '%s' (%s)\n",
1443		    (void *)addr, (void *)bt->bt_start,
1444		    (vmem_size_t)(addr - bt->bt_start), vm->vm_name,
1445		    (bt->bt_type == BT_TYPE_BUSY) ? "allocated" : "free");
1446	}
1447}
1448
1449void
1450vmem_printall(const char *modif, int (*pr)(const char *, ...))
1451{
1452	const vmem_t *vm;
1453
1454	LIST_FOREACH(vm, &vmem_list, vm_alllist) {
1455		vmem_dump(vm, pr);
1456	}
1457}
1458
1459void
1460vmem_print(vmem_addr_t addr, const char *modif, int (*pr)(const char *, ...))
1461{
1462	const vmem_t *vm = (const void *)addr;
1463
1464	vmem_dump(vm, pr);
1465}
1466
1467DB_SHOW_COMMAND(vmemdump, vmemdump)
1468{
1469
1470	if (!have_addr) {
1471		db_printf("usage: show vmemdump <addr>\n");
1472		return;
1473	}
1474
1475	vmem_dump((const vmem_t *)addr, db_printf);
1476}
1477
1478DB_SHOW_ALL_COMMAND(vmemdump, vmemdumpall)
1479{
1480	const vmem_t *vm;
1481
1482	LIST_FOREACH(vm, &vmem_list, vm_alllist)
1483		vmem_dump(vm, db_printf);
1484}
1485
1486DB_SHOW_COMMAND(vmem, vmem_summ)
1487{
1488	const vmem_t *vm = (const void *)addr;
1489	const bt_t *bt;
1490	size_t ft[VMEM_MAXORDER], ut[VMEM_MAXORDER];
1491	size_t fs[VMEM_MAXORDER], us[VMEM_MAXORDER];
1492	int ord;
1493
1494	if (!have_addr) {
1495		db_printf("usage: show vmem <addr>\n");
1496		return;
1497	}
1498
1499	db_printf("vmem %p '%s'\n", vm, vm->vm_name);
1500	db_printf("\tquantum:\t%zu\n", vm->vm_quantum_mask + 1);
1501	db_printf("\tsize:\t%zu\n", vm->vm_size);
1502	db_printf("\tinuse:\t%zu\n", vm->vm_inuse);
1503	db_printf("\tfree:\t%zu\n", vm->vm_size - vm->vm_inuse);
1504	db_printf("\tbusy tags:\t%d\n", vm->vm_nbusytag);
1505	db_printf("\tfree tags:\t%d\n", vm->vm_nfreetags);
1506
1507	memset(&ft, 0, sizeof(ft));
1508	memset(&ut, 0, sizeof(ut));
1509	memset(&fs, 0, sizeof(fs));
1510	memset(&us, 0, sizeof(us));
1511	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1512		ord = SIZE2ORDER(bt->bt_size >> vm->vm_quantum_shift);
1513		if (bt->bt_type == BT_TYPE_BUSY) {
1514			ut[ord]++;
1515			us[ord] += bt->bt_size;
1516		} else if (bt->bt_type == BT_TYPE_FREE) {
1517			ft[ord]++;
1518			fs[ord] += bt->bt_size;
1519		}
1520	}
1521	db_printf("\t\t\tinuse\tsize\t\tfree\tsize\n");
1522	for (ord = 0; ord < VMEM_MAXORDER; ord++) {
1523		if (ut[ord] == 0 && ft[ord] == 0)
1524			continue;
1525		db_printf("\t%-15zu %zu\t%-15zu %zu\t%-16zu\n",
1526		    ORDER2SIZE(ord) << vm->vm_quantum_shift,
1527		    ut[ord], us[ord], ft[ord], fs[ord]);
1528	}
1529}
1530
1531DB_SHOW_ALL_COMMAND(vmem, vmem_summall)
1532{
1533	const vmem_t *vm;
1534
1535	LIST_FOREACH(vm, &vmem_list, vm_alllist)
1536		vmem_summ((db_expr_t)vm, TRUE, count, modif);
1537}
1538#endif /* defined(DDB) */
1539
1540#define vmem_printf printf
1541
1542#if defined(DIAGNOSTIC)
1543
1544static bool
1545vmem_check_sanity(vmem_t *vm)
1546{
1547	const bt_t *bt, *bt2;
1548
1549	MPASS(vm != NULL);
1550
1551	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1552		if (bt->bt_start > BT_END(bt)) {
1553			printf("corrupted tag\n");
1554			bt_dump(bt, vmem_printf);
1555			return false;
1556		}
1557	}
1558	TAILQ_FOREACH(bt, &vm->vm_seglist, bt_seglist) {
1559		TAILQ_FOREACH(bt2, &vm->vm_seglist, bt_seglist) {
1560			if (bt == bt2) {
1561				continue;
1562			}
1563			if (BT_ISSPAN_P(bt) != BT_ISSPAN_P(bt2)) {
1564				continue;
1565			}
1566			if (bt->bt_start <= BT_END(bt2) &&
1567			    bt2->bt_start <= BT_END(bt)) {
1568				printf("overwrapped tags\n");
1569				bt_dump(bt, vmem_printf);
1570				bt_dump(bt2, vmem_printf);
1571				return false;
1572			}
1573		}
1574	}
1575
1576	return true;
1577}
1578
1579static void
1580vmem_check(vmem_t *vm)
1581{
1582
1583	if (!vmem_check_sanity(vm)) {
1584		panic("insanity vmem %p", vm);
1585	}
1586}
1587
1588#endif /* defined(DIAGNOSTIC) */
1589