xref: /freebsd/sys/vm/vm_page.c (revision 1781ad707e1278d05f66038a44652a76a02f8567)
1 /*-
2  * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU)
3  *
4  * Copyright (c) 1991 Regents of the University of California.
5  * All rights reserved.
6  * Copyright (c) 1998 Matthew Dillon.  All Rights Reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * The Mach Operating System project at Carnegie-Mellon University.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	from: @(#)vm_page.c	7.4 (Berkeley) 5/7/91
36  */
37 
38 /*-
39  * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40  * All rights reserved.
41  *
42  * Authors: Avadis Tevanian, Jr., Michael Wayne Young
43  *
44  * Permission to use, copy, modify and distribute this software and
45  * its documentation is hereby granted, provided that both the copyright
46  * notice and this permission notice appear in all copies of the
47  * software, derivative works or modified versions, and any portions
48  * thereof, and that both notices appear in supporting documentation.
49  *
50  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
51  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
52  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
53  *
54  * Carnegie Mellon requests users of this software to return to
55  *
56  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
57  *  School of Computer Science
58  *  Carnegie Mellon University
59  *  Pittsburgh PA 15213-3890
60  *
61  * any improvements or extensions that they make and grant Carnegie the
62  * rights to redistribute these changes.
63  */
64 
65 /*
66  *	Resident memory management module.
67  */
68 
69 #include <sys/cdefs.h>
70 __FBSDID("$FreeBSD$");
71 
72 #include "opt_vm.h"
73 
74 #include <sys/param.h>
75 #include <sys/systm.h>
76 #include <sys/lock.h>
77 #include <sys/domainset.h>
78 #include <sys/kernel.h>
79 #include <sys/limits.h>
80 #include <sys/linker.h>
81 #include <sys/malloc.h>
82 #include <sys/mman.h>
83 #include <sys/msgbuf.h>
84 #include <sys/mutex.h>
85 #include <sys/proc.h>
86 #include <sys/rwlock.h>
87 #include <sys/sleepqueue.h>
88 #include <sys/sbuf.h>
89 #include <sys/sched.h>
90 #include <sys/smp.h>
91 #include <sys/sysctl.h>
92 #include <sys/vmmeter.h>
93 #include <sys/vnode.h>
94 
95 #include <vm/vm.h>
96 #include <vm/pmap.h>
97 #include <vm/vm_param.h>
98 #include <vm/vm_domainset.h>
99 #include <vm/vm_kern.h>
100 #include <vm/vm_map.h>
101 #include <vm/vm_object.h>
102 #include <vm/vm_page.h>
103 #include <vm/vm_pageout.h>
104 #include <vm/vm_phys.h>
105 #include <vm/vm_pagequeue.h>
106 #include <vm/vm_pager.h>
107 #include <vm/vm_radix.h>
108 #include <vm/vm_reserv.h>
109 #include <vm/vm_extern.h>
110 #include <vm/uma.h>
111 #include <vm/uma_int.h>
112 
113 #include <machine/md_var.h>
114 
115 extern int	uma_startup_count(int);
116 extern void	uma_startup(void *, int);
117 extern int	vmem_startup_count(void);
118 
119 struct vm_domain vm_dom[MAXMEMDOM];
120 
121 DPCPU_DEFINE_STATIC(struct vm_batchqueue, pqbatch[MAXMEMDOM][PQ_COUNT]);
122 
123 struct mtx_padalign __exclusive_cache_line pa_lock[PA_LOCK_COUNT];
124 
125 struct mtx_padalign __exclusive_cache_line vm_domainset_lock;
126 /* The following fields are protected by the domainset lock. */
127 domainset_t __exclusive_cache_line vm_min_domains;
128 domainset_t __exclusive_cache_line vm_severe_domains;
129 static int vm_min_waiters;
130 static int vm_severe_waiters;
131 static int vm_pageproc_waiters;
132 
133 /*
134  * bogus page -- for I/O to/from partially complete buffers,
135  * or for paging into sparsely invalid regions.
136  */
137 vm_page_t bogus_page;
138 
139 vm_page_t vm_page_array;
140 long vm_page_array_size;
141 long first_page;
142 
143 static int boot_pages;
144 SYSCTL_INT(_vm, OID_AUTO, boot_pages, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
145     &boot_pages, 0,
146     "number of pages allocated for bootstrapping the VM system");
147 
148 static int pa_tryrelock_restart;
149 SYSCTL_INT(_vm, OID_AUTO, tryrelock_restart, CTLFLAG_RD,
150     &pa_tryrelock_restart, 0, "Number of tryrelock restarts");
151 
152 static TAILQ_HEAD(, vm_page) blacklist_head;
153 static int sysctl_vm_page_blacklist(SYSCTL_HANDLER_ARGS);
154 SYSCTL_PROC(_vm, OID_AUTO, page_blacklist, CTLTYPE_STRING | CTLFLAG_RD |
155     CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_page_blacklist, "A", "Blacklist pages");
156 
157 static uma_zone_t fakepg_zone;
158 
159 static void vm_page_alloc_check(vm_page_t m);
160 static void vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits);
161 static void vm_page_dequeue_complete(vm_page_t m);
162 static void vm_page_enqueue(vm_page_t m, uint8_t queue);
163 static void vm_page_init(void *dummy);
164 static int vm_page_insert_after(vm_page_t m, vm_object_t object,
165     vm_pindex_t pindex, vm_page_t mpred);
166 static void vm_page_insert_radixdone(vm_page_t m, vm_object_t object,
167     vm_page_t mpred);
168 static void vm_page_mvqueue(vm_page_t m, uint8_t queue);
169 static int vm_page_reclaim_run(int req_class, int domain, u_long npages,
170     vm_page_t m_run, vm_paddr_t high);
171 static int vm_domain_alloc_fail(struct vm_domain *vmd, vm_object_t object,
172     int req);
173 static int vm_page_zone_import(void *arg, void **store, int cnt, int domain,
174     int flags);
175 static void vm_page_zone_release(void *arg, void **store, int cnt);
176 
177 SYSINIT(vm_page, SI_SUB_VM, SI_ORDER_SECOND, vm_page_init, NULL);
178 
179 static void
180 vm_page_init(void *dummy)
181 {
182 
183 	fakepg_zone = uma_zcreate("fakepg", sizeof(struct vm_page), NULL, NULL,
184 	    NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE | UMA_ZONE_VM);
185 	bogus_page = vm_page_alloc(NULL, 0, VM_ALLOC_NOOBJ |
186 	    VM_ALLOC_NORMAL | VM_ALLOC_WIRED);
187 }
188 
189 /*
190  * The cache page zone is initialized later since we need to be able to allocate
191  * pages before UMA is fully initialized.
192  */
193 static void
194 vm_page_init_cache_zones(void *dummy __unused)
195 {
196 	struct vm_domain *vmd;
197 	struct vm_pgcache *pgcache;
198 	int domain, pool;
199 
200 	for (domain = 0; domain < vm_ndomains; domain++) {
201 		vmd = VM_DOMAIN(domain);
202 
203 		/*
204 		 * Don't allow the page caches to take up more than .25% of
205 		 * memory.
206 		 */
207 		if (vmd->vmd_page_count / 400 < 256 * mp_ncpus * VM_NFREEPOOL)
208 			continue;
209 		for (pool = 0; pool < VM_NFREEPOOL; pool++) {
210 			pgcache = &vmd->vmd_pgcache[pool];
211 			pgcache->domain = domain;
212 			pgcache->pool = pool;
213 			pgcache->zone = uma_zcache_create("vm pgcache",
214 			    sizeof(struct vm_page), NULL, NULL, NULL, NULL,
215 			    vm_page_zone_import, vm_page_zone_release, pgcache,
216 			    UMA_ZONE_MAXBUCKET | UMA_ZONE_VM);
217 			(void)uma_zone_set_maxcache(pgcache->zone, 0);
218 		}
219 	}
220 }
221 SYSINIT(vm_page2, SI_SUB_VM_CONF, SI_ORDER_ANY, vm_page_init_cache_zones, NULL);
222 
223 /* Make sure that u_long is at least 64 bits when PAGE_SIZE is 32K. */
224 #if PAGE_SIZE == 32768
225 #ifdef CTASSERT
226 CTASSERT(sizeof(u_long) >= 8);
227 #endif
228 #endif
229 
230 /*
231  * Try to acquire a physical address lock while a pmap is locked.  If we
232  * fail to trylock we unlock and lock the pmap directly and cache the
233  * locked pa in *locked.  The caller should then restart their loop in case
234  * the virtual to physical mapping has changed.
235  */
236 int
237 vm_page_pa_tryrelock(pmap_t pmap, vm_paddr_t pa, vm_paddr_t *locked)
238 {
239 	vm_paddr_t lockpa;
240 
241 	lockpa = *locked;
242 	*locked = pa;
243 	if (lockpa) {
244 		PA_LOCK_ASSERT(lockpa, MA_OWNED);
245 		if (PA_LOCKPTR(pa) == PA_LOCKPTR(lockpa))
246 			return (0);
247 		PA_UNLOCK(lockpa);
248 	}
249 	if (PA_TRYLOCK(pa))
250 		return (0);
251 	PMAP_UNLOCK(pmap);
252 	atomic_add_int(&pa_tryrelock_restart, 1);
253 	PA_LOCK(pa);
254 	PMAP_LOCK(pmap);
255 	return (EAGAIN);
256 }
257 
258 /*
259  *	vm_set_page_size:
260  *
261  *	Sets the page size, perhaps based upon the memory
262  *	size.  Must be called before any use of page-size
263  *	dependent functions.
264  */
265 void
266 vm_set_page_size(void)
267 {
268 	if (vm_cnt.v_page_size == 0)
269 		vm_cnt.v_page_size = PAGE_SIZE;
270 	if (((vm_cnt.v_page_size - 1) & vm_cnt.v_page_size) != 0)
271 		panic("vm_set_page_size: page size not a power of two");
272 }
273 
274 /*
275  *	vm_page_blacklist_next:
276  *
277  *	Find the next entry in the provided string of blacklist
278  *	addresses.  Entries are separated by space, comma, or newline.
279  *	If an invalid integer is encountered then the rest of the
280  *	string is skipped.  Updates the list pointer to the next
281  *	character, or NULL if the string is exhausted or invalid.
282  */
283 static vm_paddr_t
284 vm_page_blacklist_next(char **list, char *end)
285 {
286 	vm_paddr_t bad;
287 	char *cp, *pos;
288 
289 	if (list == NULL || *list == NULL)
290 		return (0);
291 	if (**list =='\0') {
292 		*list = NULL;
293 		return (0);
294 	}
295 
296 	/*
297 	 * If there's no end pointer then the buffer is coming from
298 	 * the kenv and we know it's null-terminated.
299 	 */
300 	if (end == NULL)
301 		end = *list + strlen(*list);
302 
303 	/* Ensure that strtoq() won't walk off the end */
304 	if (*end != '\0') {
305 		if (*end == '\n' || *end == ' ' || *end  == ',')
306 			*end = '\0';
307 		else {
308 			printf("Blacklist not terminated, skipping\n");
309 			*list = NULL;
310 			return (0);
311 		}
312 	}
313 
314 	for (pos = *list; *pos != '\0'; pos = cp) {
315 		bad = strtoq(pos, &cp, 0);
316 		if (*cp == '\0' || *cp == ' ' || *cp == ',' || *cp == '\n') {
317 			if (bad == 0) {
318 				if (++cp < end)
319 					continue;
320 				else
321 					break;
322 			}
323 		} else
324 			break;
325 		if (*cp == '\0' || ++cp >= end)
326 			*list = NULL;
327 		else
328 			*list = cp;
329 		return (trunc_page(bad));
330 	}
331 	printf("Garbage in RAM blacklist, skipping\n");
332 	*list = NULL;
333 	return (0);
334 }
335 
336 bool
337 vm_page_blacklist_add(vm_paddr_t pa, bool verbose)
338 {
339 	struct vm_domain *vmd;
340 	vm_page_t m;
341 	int ret;
342 
343 	m = vm_phys_paddr_to_vm_page(pa);
344 	if (m == NULL)
345 		return (true); /* page does not exist, no failure */
346 
347 	vmd = vm_pagequeue_domain(m);
348 	vm_domain_free_lock(vmd);
349 	ret = vm_phys_unfree_page(m);
350 	vm_domain_free_unlock(vmd);
351 	if (ret != 0) {
352 		vm_domain_freecnt_inc(vmd, -1);
353 		TAILQ_INSERT_TAIL(&blacklist_head, m, listq);
354 		if (verbose)
355 			printf("Skipping page with pa 0x%jx\n", (uintmax_t)pa);
356 	}
357 	return (ret);
358 }
359 
360 /*
361  *	vm_page_blacklist_check:
362  *
363  *	Iterate through the provided string of blacklist addresses, pulling
364  *	each entry out of the physical allocator free list and putting it
365  *	onto a list for reporting via the vm.page_blacklist sysctl.
366  */
367 static void
368 vm_page_blacklist_check(char *list, char *end)
369 {
370 	vm_paddr_t pa;
371 	char *next;
372 
373 	next = list;
374 	while (next != NULL) {
375 		if ((pa = vm_page_blacklist_next(&next, end)) == 0)
376 			continue;
377 		vm_page_blacklist_add(pa, bootverbose);
378 	}
379 }
380 
381 /*
382  *	vm_page_blacklist_load:
383  *
384  *	Search for a special module named "ram_blacklist".  It'll be a
385  *	plain text file provided by the user via the loader directive
386  *	of the same name.
387  */
388 static void
389 vm_page_blacklist_load(char **list, char **end)
390 {
391 	void *mod;
392 	u_char *ptr;
393 	u_int len;
394 
395 	mod = NULL;
396 	ptr = NULL;
397 
398 	mod = preload_search_by_type("ram_blacklist");
399 	if (mod != NULL) {
400 		ptr = preload_fetch_addr(mod);
401 		len = preload_fetch_size(mod);
402         }
403 	*list = ptr;
404 	if (ptr != NULL)
405 		*end = ptr + len;
406 	else
407 		*end = NULL;
408 	return;
409 }
410 
411 static int
412 sysctl_vm_page_blacklist(SYSCTL_HANDLER_ARGS)
413 {
414 	vm_page_t m;
415 	struct sbuf sbuf;
416 	int error, first;
417 
418 	first = 1;
419 	error = sysctl_wire_old_buffer(req, 0);
420 	if (error != 0)
421 		return (error);
422 	sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
423 	TAILQ_FOREACH(m, &blacklist_head, listq) {
424 		sbuf_printf(&sbuf, "%s%#jx", first ? "" : ",",
425 		    (uintmax_t)m->phys_addr);
426 		first = 0;
427 	}
428 	error = sbuf_finish(&sbuf);
429 	sbuf_delete(&sbuf);
430 	return (error);
431 }
432 
433 /*
434  * Initialize a dummy page for use in scans of the specified paging queue.
435  * In principle, this function only needs to set the flag PG_MARKER.
436  * Nonetheless, it write busies the page as a safety precaution.
437  */
438 static void
439 vm_page_init_marker(vm_page_t marker, int queue, uint8_t aflags)
440 {
441 
442 	bzero(marker, sizeof(*marker));
443 	marker->flags = PG_MARKER;
444 	marker->aflags = aflags;
445 	marker->busy_lock = VPB_SINGLE_EXCLUSIVER;
446 	marker->queue = queue;
447 }
448 
449 static void
450 vm_page_domain_init(int domain)
451 {
452 	struct vm_domain *vmd;
453 	struct vm_pagequeue *pq;
454 	int i;
455 
456 	vmd = VM_DOMAIN(domain);
457 	bzero(vmd, sizeof(*vmd));
458 	*__DECONST(char **, &vmd->vmd_pagequeues[PQ_INACTIVE].pq_name) =
459 	    "vm inactive pagequeue";
460 	*__DECONST(char **, &vmd->vmd_pagequeues[PQ_ACTIVE].pq_name) =
461 	    "vm active pagequeue";
462 	*__DECONST(char **, &vmd->vmd_pagequeues[PQ_LAUNDRY].pq_name) =
463 	    "vm laundry pagequeue";
464 	*__DECONST(char **, &vmd->vmd_pagequeues[PQ_UNSWAPPABLE].pq_name) =
465 	    "vm unswappable pagequeue";
466 	vmd->vmd_domain = domain;
467 	vmd->vmd_page_count = 0;
468 	vmd->vmd_free_count = 0;
469 	vmd->vmd_segs = 0;
470 	vmd->vmd_oom = FALSE;
471 	for (i = 0; i < PQ_COUNT; i++) {
472 		pq = &vmd->vmd_pagequeues[i];
473 		TAILQ_INIT(&pq->pq_pl);
474 		mtx_init(&pq->pq_mutex, pq->pq_name, "vm pagequeue",
475 		    MTX_DEF | MTX_DUPOK);
476 		pq->pq_pdpages = 0;
477 		vm_page_init_marker(&vmd->vmd_markers[i], i, 0);
478 	}
479 	mtx_init(&vmd->vmd_free_mtx, "vm page free queue", NULL, MTX_DEF);
480 	mtx_init(&vmd->vmd_pageout_mtx, "vm pageout lock", NULL, MTX_DEF);
481 	snprintf(vmd->vmd_name, sizeof(vmd->vmd_name), "%d", domain);
482 
483 	/*
484 	 * inacthead is used to provide FIFO ordering for LRU-bypassing
485 	 * insertions.
486 	 */
487 	vm_page_init_marker(&vmd->vmd_inacthead, PQ_INACTIVE, PGA_ENQUEUED);
488 	TAILQ_INSERT_HEAD(&vmd->vmd_pagequeues[PQ_INACTIVE].pq_pl,
489 	    &vmd->vmd_inacthead, plinks.q);
490 
491 	/*
492 	 * The clock pages are used to implement active queue scanning without
493 	 * requeues.  Scans start at clock[0], which is advanced after the scan
494 	 * ends.  When the two clock hands meet, they are reset and scanning
495 	 * resumes from the head of the queue.
496 	 */
497 	vm_page_init_marker(&vmd->vmd_clock[0], PQ_ACTIVE, PGA_ENQUEUED);
498 	vm_page_init_marker(&vmd->vmd_clock[1], PQ_ACTIVE, PGA_ENQUEUED);
499 	TAILQ_INSERT_HEAD(&vmd->vmd_pagequeues[PQ_ACTIVE].pq_pl,
500 	    &vmd->vmd_clock[0], plinks.q);
501 	TAILQ_INSERT_TAIL(&vmd->vmd_pagequeues[PQ_ACTIVE].pq_pl,
502 	    &vmd->vmd_clock[1], plinks.q);
503 }
504 
505 /*
506  * Initialize a physical page in preparation for adding it to the free
507  * lists.
508  */
509 static void
510 vm_page_init_page(vm_page_t m, vm_paddr_t pa, int segind)
511 {
512 
513 	m->object = NULL;
514 	m->ref_count = 0;
515 	m->busy_lock = VPB_UNBUSIED;
516 	m->flags = m->aflags = 0;
517 	m->phys_addr = pa;
518 	m->queue = PQ_NONE;
519 	m->psind = 0;
520 	m->segind = segind;
521 	m->order = VM_NFREEORDER;
522 	m->pool = VM_FREEPOOL_DEFAULT;
523 	m->valid = m->dirty = 0;
524 	pmap_page_init(m);
525 }
526 
527 #ifndef PMAP_HAS_PAGE_ARRAY
528 static vm_paddr_t
529 vm_page_array_alloc(vm_offset_t *vaddr, vm_paddr_t end, vm_paddr_t page_range)
530 {
531 	vm_paddr_t new_end;
532 
533 	/*
534 	 * Reserve an unmapped guard page to trap access to vm_page_array[-1].
535 	 * However, because this page is allocated from KVM, out-of-bounds
536 	 * accesses using the direct map will not be trapped.
537 	 */
538 	*vaddr += PAGE_SIZE;
539 
540 	/*
541 	 * Allocate physical memory for the page structures, and map it.
542 	 */
543 	new_end = trunc_page(end - page_range * sizeof(struct vm_page));
544 	vm_page_array = (vm_page_t)pmap_map(vaddr, new_end, end,
545 	    VM_PROT_READ | VM_PROT_WRITE);
546 	vm_page_array_size = page_range;
547 
548 	return (new_end);
549 }
550 #endif
551 
552 /*
553  *	vm_page_startup:
554  *
555  *	Initializes the resident memory module.  Allocates physical memory for
556  *	bootstrapping UMA and some data structures that are used to manage
557  *	physical pages.  Initializes these structures, and populates the free
558  *	page queues.
559  */
560 vm_offset_t
561 vm_page_startup(vm_offset_t vaddr)
562 {
563 	struct vm_phys_seg *seg;
564 	vm_page_t m;
565 	char *list, *listend;
566 	vm_offset_t mapped;
567 	vm_paddr_t end, high_avail, low_avail, new_end, page_range, size;
568 	vm_paddr_t last_pa, pa;
569 	u_long pagecount;
570 	int biggestone, i, segind;
571 #ifdef WITNESS
572 	int witness_size;
573 #endif
574 #if defined(__i386__) && defined(VM_PHYSSEG_DENSE)
575 	long ii;
576 #endif
577 
578 	vaddr = round_page(vaddr);
579 
580 	vm_phys_early_startup();
581 	biggestone = vm_phys_avail_largest();
582 	end = phys_avail[biggestone+1];
583 
584 	/*
585 	 * Initialize the page and queue locks.
586 	 */
587 	mtx_init(&vm_domainset_lock, "vm domainset lock", NULL, MTX_DEF);
588 	for (i = 0; i < PA_LOCK_COUNT; i++)
589 		mtx_init(&pa_lock[i], "vm page", NULL, MTX_DEF);
590 	for (i = 0; i < vm_ndomains; i++)
591 		vm_page_domain_init(i);
592 
593 	/*
594 	 * Allocate memory for use when boot strapping the kernel memory
595 	 * allocator.  Tell UMA how many zones we are going to create
596 	 * before going fully functional.  UMA will add its zones.
597 	 *
598 	 * VM startup zones: vmem, vmem_btag, VM OBJECT, RADIX NODE, MAP,
599 	 * KMAP ENTRY, MAP ENTRY, VMSPACE.
600 	 */
601 	boot_pages = uma_startup_count(8);
602 
603 #ifndef UMA_MD_SMALL_ALLOC
604 	/* vmem_startup() calls uma_prealloc(). */
605 	boot_pages += vmem_startup_count();
606 	/* vm_map_startup() calls uma_prealloc(). */
607 	boot_pages += howmany(MAX_KMAP,
608 	    UMA_SLAB_SPACE / sizeof(struct vm_map));
609 
610 	/*
611 	 * Before going fully functional kmem_init() does allocation
612 	 * from "KMAP ENTRY" and vmem_create() does allocation from "vmem".
613 	 */
614 	boot_pages += 2;
615 #endif
616 	/*
617 	 * CTFLAG_RDTUN doesn't work during the early boot process, so we must
618 	 * manually fetch the value.
619 	 */
620 	TUNABLE_INT_FETCH("vm.boot_pages", &boot_pages);
621 	new_end = end - (boot_pages * UMA_SLAB_SIZE);
622 	new_end = trunc_page(new_end);
623 	mapped = pmap_map(&vaddr, new_end, end,
624 	    VM_PROT_READ | VM_PROT_WRITE);
625 	bzero((void *)mapped, end - new_end);
626 	uma_startup((void *)mapped, boot_pages);
627 
628 #ifdef WITNESS
629 	witness_size = round_page(witness_startup_count());
630 	new_end -= witness_size;
631 	mapped = pmap_map(&vaddr, new_end, new_end + witness_size,
632 	    VM_PROT_READ | VM_PROT_WRITE);
633 	bzero((void *)mapped, witness_size);
634 	witness_startup((void *)mapped);
635 #endif
636 
637 #if defined(__aarch64__) || defined(__amd64__) || defined(__arm__) || \
638     defined(__i386__) || defined(__mips__) || defined(__riscv)
639 	/*
640 	 * Allocate a bitmap to indicate that a random physical page
641 	 * needs to be included in a minidump.
642 	 *
643 	 * The amd64 port needs this to indicate which direct map pages
644 	 * need to be dumped, via calls to dump_add_page()/dump_drop_page().
645 	 *
646 	 * However, i386 still needs this workspace internally within the
647 	 * minidump code.  In theory, they are not needed on i386, but are
648 	 * included should the sf_buf code decide to use them.
649 	 */
650 	last_pa = 0;
651 	for (i = 0; dump_avail[i + 1] != 0; i += 2)
652 		if (dump_avail[i + 1] > last_pa)
653 			last_pa = dump_avail[i + 1];
654 	page_range = last_pa / PAGE_SIZE;
655 	vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY);
656 	new_end -= vm_page_dump_size;
657 	vm_page_dump = (void *)(uintptr_t)pmap_map(&vaddr, new_end,
658 	    new_end + vm_page_dump_size, VM_PROT_READ | VM_PROT_WRITE);
659 	bzero((void *)vm_page_dump, vm_page_dump_size);
660 #else
661 	(void)last_pa;
662 #endif
663 #if defined(__aarch64__) || defined(__amd64__) || defined(__mips__) || \
664     defined(__riscv)
665 	/*
666 	 * Include the UMA bootstrap pages, witness pages and vm_page_dump
667 	 * in a crash dump.  When pmap_map() uses the direct map, they are
668 	 * not automatically included.
669 	 */
670 	for (pa = new_end; pa < end; pa += PAGE_SIZE)
671 		dump_add_page(pa);
672 #endif
673 	phys_avail[biggestone + 1] = new_end;
674 #ifdef __amd64__
675 	/*
676 	 * Request that the physical pages underlying the message buffer be
677 	 * included in a crash dump.  Since the message buffer is accessed
678 	 * through the direct map, they are not automatically included.
679 	 */
680 	pa = DMAP_TO_PHYS((vm_offset_t)msgbufp->msg_ptr);
681 	last_pa = pa + round_page(msgbufsize);
682 	while (pa < last_pa) {
683 		dump_add_page(pa);
684 		pa += PAGE_SIZE;
685 	}
686 #endif
687 	/*
688 	 * Compute the number of pages of memory that will be available for
689 	 * use, taking into account the overhead of a page structure per page.
690 	 * In other words, solve
691 	 *	"available physical memory" - round_page(page_range *
692 	 *	    sizeof(struct vm_page)) = page_range * PAGE_SIZE
693 	 * for page_range.
694 	 */
695 	low_avail = phys_avail[0];
696 	high_avail = phys_avail[1];
697 	for (i = 0; i < vm_phys_nsegs; i++) {
698 		if (vm_phys_segs[i].start < low_avail)
699 			low_avail = vm_phys_segs[i].start;
700 		if (vm_phys_segs[i].end > high_avail)
701 			high_avail = vm_phys_segs[i].end;
702 	}
703 	/* Skip the first chunk.  It is already accounted for. */
704 	for (i = 2; phys_avail[i + 1] != 0; i += 2) {
705 		if (phys_avail[i] < low_avail)
706 			low_avail = phys_avail[i];
707 		if (phys_avail[i + 1] > high_avail)
708 			high_avail = phys_avail[i + 1];
709 	}
710 	first_page = low_avail / PAGE_SIZE;
711 #ifdef VM_PHYSSEG_SPARSE
712 	size = 0;
713 	for (i = 0; i < vm_phys_nsegs; i++)
714 		size += vm_phys_segs[i].end - vm_phys_segs[i].start;
715 	for (i = 0; phys_avail[i + 1] != 0; i += 2)
716 		size += phys_avail[i + 1] - phys_avail[i];
717 #elif defined(VM_PHYSSEG_DENSE)
718 	size = high_avail - low_avail;
719 #else
720 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined."
721 #endif
722 
723 #ifdef PMAP_HAS_PAGE_ARRAY
724 	pmap_page_array_startup(size / PAGE_SIZE);
725 	biggestone = vm_phys_avail_largest();
726 	end = new_end = phys_avail[biggestone + 1];
727 #else
728 #ifdef VM_PHYSSEG_DENSE
729 	/*
730 	 * In the VM_PHYSSEG_DENSE case, the number of pages can account for
731 	 * the overhead of a page structure per page only if vm_page_array is
732 	 * allocated from the last physical memory chunk.  Otherwise, we must
733 	 * allocate page structures representing the physical memory
734 	 * underlying vm_page_array, even though they will not be used.
735 	 */
736 	if (new_end != high_avail)
737 		page_range = size / PAGE_SIZE;
738 	else
739 #endif
740 	{
741 		page_range = size / (PAGE_SIZE + sizeof(struct vm_page));
742 
743 		/*
744 		 * If the partial bytes remaining are large enough for
745 		 * a page (PAGE_SIZE) without a corresponding
746 		 * 'struct vm_page', then new_end will contain an
747 		 * extra page after subtracting the length of the VM
748 		 * page array.  Compensate by subtracting an extra
749 		 * page from new_end.
750 		 */
751 		if (size % (PAGE_SIZE + sizeof(struct vm_page)) >= PAGE_SIZE) {
752 			if (new_end == high_avail)
753 				high_avail -= PAGE_SIZE;
754 			new_end -= PAGE_SIZE;
755 		}
756 	}
757 	end = new_end;
758 	new_end = vm_page_array_alloc(&vaddr, end, page_range);
759 #endif
760 
761 #if VM_NRESERVLEVEL > 0
762 	/*
763 	 * Allocate physical memory for the reservation management system's
764 	 * data structures, and map it.
765 	 */
766 	new_end = vm_reserv_startup(&vaddr, new_end);
767 #endif
768 #if defined(__aarch64__) || defined(__amd64__) || defined(__mips__) || \
769     defined(__riscv)
770 	/*
771 	 * Include vm_page_array and vm_reserv_array in a crash dump.
772 	 */
773 	for (pa = new_end; pa < end; pa += PAGE_SIZE)
774 		dump_add_page(pa);
775 #endif
776 	phys_avail[biggestone + 1] = new_end;
777 
778 	/*
779 	 * Add physical memory segments corresponding to the available
780 	 * physical pages.
781 	 */
782 	for (i = 0; phys_avail[i + 1] != 0; i += 2)
783 		if (vm_phys_avail_size(i) != 0)
784 			vm_phys_add_seg(phys_avail[i], phys_avail[i + 1]);
785 
786 	/*
787 	 * Initialize the physical memory allocator.
788 	 */
789 	vm_phys_init();
790 
791 	/*
792 	 * Initialize the page structures and add every available page to the
793 	 * physical memory allocator's free lists.
794 	 */
795 #if defined(__i386__) && defined(VM_PHYSSEG_DENSE)
796 	for (ii = 0; ii < vm_page_array_size; ii++) {
797 		m = &vm_page_array[ii];
798 		vm_page_init_page(m, (first_page + ii) << PAGE_SHIFT, 0);
799 		m->flags = PG_FICTITIOUS;
800 	}
801 #endif
802 	vm_cnt.v_page_count = 0;
803 	for (segind = 0; segind < vm_phys_nsegs; segind++) {
804 		seg = &vm_phys_segs[segind];
805 		for (m = seg->first_page, pa = seg->start; pa < seg->end;
806 		    m++, pa += PAGE_SIZE)
807 			vm_page_init_page(m, pa, segind);
808 
809 		/*
810 		 * Add the segment to the free lists only if it is covered by
811 		 * one of the ranges in phys_avail.  Because we've added the
812 		 * ranges to the vm_phys_segs array, we can assume that each
813 		 * segment is either entirely contained in one of the ranges,
814 		 * or doesn't overlap any of them.
815 		 */
816 		for (i = 0; phys_avail[i + 1] != 0; i += 2) {
817 			struct vm_domain *vmd;
818 
819 			if (seg->start < phys_avail[i] ||
820 			    seg->end > phys_avail[i + 1])
821 				continue;
822 
823 			m = seg->first_page;
824 			pagecount = (u_long)atop(seg->end - seg->start);
825 
826 			vmd = VM_DOMAIN(seg->domain);
827 			vm_domain_free_lock(vmd);
828 			vm_phys_enqueue_contig(m, pagecount);
829 			vm_domain_free_unlock(vmd);
830 			vm_domain_freecnt_inc(vmd, pagecount);
831 			vm_cnt.v_page_count += (u_int)pagecount;
832 
833 			vmd = VM_DOMAIN(seg->domain);
834 			vmd->vmd_page_count += (u_int)pagecount;
835 			vmd->vmd_segs |= 1UL << m->segind;
836 			break;
837 		}
838 	}
839 
840 	/*
841 	 * Remove blacklisted pages from the physical memory allocator.
842 	 */
843 	TAILQ_INIT(&blacklist_head);
844 	vm_page_blacklist_load(&list, &listend);
845 	vm_page_blacklist_check(list, listend);
846 
847 	list = kern_getenv("vm.blacklist");
848 	vm_page_blacklist_check(list, NULL);
849 
850 	freeenv(list);
851 #if VM_NRESERVLEVEL > 0
852 	/*
853 	 * Initialize the reservation management system.
854 	 */
855 	vm_reserv_init();
856 #endif
857 
858 	return (vaddr);
859 }
860 
861 void
862 vm_page_reference(vm_page_t m)
863 {
864 
865 	vm_page_aflag_set(m, PGA_REFERENCED);
866 }
867 
868 /*
869  *	vm_page_busy_acquire:
870  *
871  *	Acquire the busy lock as described by VM_ALLOC_* flags.  Will loop
872  *	and drop the object lock if necessary.
873  */
874 int
875 vm_page_busy_acquire(vm_page_t m, int allocflags)
876 {
877 	vm_object_t obj;
878 	u_int x;
879 	bool locked;
880 
881 	/*
882 	 * The page-specific object must be cached because page
883 	 * identity can change during the sleep, causing the
884 	 * re-lock of a different object.
885 	 * It is assumed that a reference to the object is already
886 	 * held by the callers.
887 	 */
888 	obj = m->object;
889 	for (;;) {
890 		if ((allocflags & VM_ALLOC_SBUSY) == 0) {
891 			if (vm_page_tryxbusy(m))
892 				return (TRUE);
893 		} else {
894 			if (vm_page_trysbusy(m))
895 				return (TRUE);
896 		}
897 		if ((allocflags & VM_ALLOC_NOWAIT) != 0)
898 			return (FALSE);
899 		if (obj != NULL) {
900 			locked = VM_OBJECT_WOWNED(obj);
901 		} else {
902 			MPASS(vm_page_wired(m));
903 			locked = FALSE;
904 		}
905 		sleepq_lock(m);
906 		x = m->busy_lock;
907 		if (x == VPB_UNBUSIED ||
908 		    ((allocflags & VM_ALLOC_SBUSY) != 0 &&
909 		    (x & VPB_BIT_SHARED) != 0) ||
910 		    ((x & VPB_BIT_WAITERS) == 0 &&
911 		    !atomic_cmpset_int(&m->busy_lock, x,
912 		    x | VPB_BIT_WAITERS))) {
913 			sleepq_release(m);
914 			continue;
915 		}
916 		if (locked)
917 			VM_OBJECT_WUNLOCK(obj);
918 		sleepq_add(m, NULL, "vmpba", 0, 0);
919 		sleepq_wait(m, PVM);
920 		if (locked)
921 			VM_OBJECT_WLOCK(obj);
922 		MPASS(m->object == obj || m->object == NULL);
923 		if ((allocflags & VM_ALLOC_WAITFAIL) != 0)
924 			return (FALSE);
925 	}
926 }
927 
928 /*
929  *	vm_page_busy_downgrade:
930  *
931  *	Downgrade an exclusive busy page into a single shared busy page.
932  */
933 void
934 vm_page_busy_downgrade(vm_page_t m)
935 {
936 	u_int x;
937 
938 	vm_page_assert_xbusied(m);
939 
940 	x = m->busy_lock;
941 	for (;;) {
942 		if (atomic_fcmpset_rel_int(&m->busy_lock,
943 		    &x, VPB_SHARERS_WORD(1)))
944 			break;
945 	}
946 	if ((x & VPB_BIT_WAITERS) != 0)
947 		wakeup(m);
948 }
949 
950 /*
951  *	vm_page_sbusied:
952  *
953  *	Return a positive value if the page is shared busied, 0 otherwise.
954  */
955 int
956 vm_page_sbusied(vm_page_t m)
957 {
958 	u_int x;
959 
960 	x = m->busy_lock;
961 	return ((x & VPB_BIT_SHARED) != 0 && x != VPB_UNBUSIED);
962 }
963 
964 /*
965  *	vm_page_sunbusy:
966  *
967  *	Shared unbusy a page.
968  */
969 void
970 vm_page_sunbusy(vm_page_t m)
971 {
972 	u_int x;
973 
974 	vm_page_assert_sbusied(m);
975 
976 	x = m->busy_lock;
977 	for (;;) {
978 		if (VPB_SHARERS(x) > 1) {
979 			if (atomic_fcmpset_int(&m->busy_lock, &x,
980 			    x - VPB_ONE_SHARER))
981 				break;
982 			continue;
983 		}
984 		KASSERT((x & ~VPB_BIT_WAITERS) == VPB_SHARERS_WORD(1),
985 		    ("vm_page_sunbusy: invalid lock state"));
986 		if (!atomic_fcmpset_rel_int(&m->busy_lock, &x, VPB_UNBUSIED))
987 			continue;
988 		if ((x & VPB_BIT_WAITERS) == 0)
989 			break;
990 		wakeup(m);
991 		break;
992 	}
993 }
994 
995 /*
996  *	vm_page_busy_sleep:
997  *
998  *	Sleep if the page is busy, using the page pointer as wchan.
999  *	This is used to implement the hard-path of busying mechanism.
1000  *
1001  *	If nonshared is true, sleep only if the page is xbusy.
1002  *
1003  *	The object lock must be held on entry and will be released on exit.
1004  */
1005 void
1006 vm_page_busy_sleep(vm_page_t m, const char *wmesg, bool nonshared)
1007 {
1008 	vm_object_t obj;
1009 	u_int x;
1010 
1011 	obj = m->object;
1012 	vm_page_lock_assert(m, MA_NOTOWNED);
1013 	VM_OBJECT_ASSERT_LOCKED(obj);
1014 
1015 	sleepq_lock(m);
1016 	x = m->busy_lock;
1017 	if (x == VPB_UNBUSIED || (nonshared && (x & VPB_BIT_SHARED) != 0) ||
1018 	    ((x & VPB_BIT_WAITERS) == 0 &&
1019 	    !atomic_cmpset_int(&m->busy_lock, x, x | VPB_BIT_WAITERS))) {
1020 		VM_OBJECT_DROP(obj);
1021 		sleepq_release(m);
1022 		return;
1023 	}
1024 	VM_OBJECT_DROP(obj);
1025 	sleepq_add(m, NULL, wmesg, 0, 0);
1026 	sleepq_wait(m, PVM);
1027 }
1028 
1029 /*
1030  *	vm_page_trysbusy:
1031  *
1032  *	Try to shared busy a page.
1033  *	If the operation succeeds 1 is returned otherwise 0.
1034  *	The operation never sleeps.
1035  */
1036 int
1037 vm_page_trysbusy(vm_page_t m)
1038 {
1039 	u_int x;
1040 
1041 	x = m->busy_lock;
1042 	for (;;) {
1043 		if ((x & VPB_BIT_SHARED) == 0)
1044 			return (0);
1045 		if (atomic_fcmpset_acq_int(&m->busy_lock, &x,
1046 		    x + VPB_ONE_SHARER))
1047 			return (1);
1048 	}
1049 }
1050 
1051 /*
1052  *	vm_page_xunbusy_hard:
1053  *
1054  *	Called when unbusy has failed because there is a waiter.
1055  */
1056 void
1057 vm_page_xunbusy_hard(vm_page_t m)
1058 {
1059 
1060 	vm_page_assert_xbusied(m);
1061 
1062 	/*
1063 	 * Wake the waiter.
1064 	 */
1065 	atomic_store_rel_int(&m->busy_lock, VPB_UNBUSIED);
1066 	wakeup(m);
1067 }
1068 
1069 /*
1070  * Avoid releasing and reacquiring the same page lock.
1071  */
1072 void
1073 vm_page_change_lock(vm_page_t m, struct mtx **mtx)
1074 {
1075 	struct mtx *mtx1;
1076 
1077 	mtx1 = vm_page_lockptr(m);
1078 	if (*mtx == mtx1)
1079 		return;
1080 	if (*mtx != NULL)
1081 		mtx_unlock(*mtx);
1082 	*mtx = mtx1;
1083 	mtx_lock(mtx1);
1084 }
1085 
1086 /*
1087  *	vm_page_unhold_pages:
1088  *
1089  *	Unhold each of the pages that is referenced by the given array.
1090  */
1091 void
1092 vm_page_unhold_pages(vm_page_t *ma, int count)
1093 {
1094 
1095 	for (; count != 0; count--) {
1096 		vm_page_unwire(*ma, PQ_ACTIVE);
1097 		ma++;
1098 	}
1099 }
1100 
1101 vm_page_t
1102 PHYS_TO_VM_PAGE(vm_paddr_t pa)
1103 {
1104 	vm_page_t m;
1105 
1106 #ifdef VM_PHYSSEG_SPARSE
1107 	m = vm_phys_paddr_to_vm_page(pa);
1108 	if (m == NULL)
1109 		m = vm_phys_fictitious_to_vm_page(pa);
1110 	return (m);
1111 #elif defined(VM_PHYSSEG_DENSE)
1112 	long pi;
1113 
1114 	pi = atop(pa);
1115 	if (pi >= first_page && (pi - first_page) < vm_page_array_size) {
1116 		m = &vm_page_array[pi - first_page];
1117 		return (m);
1118 	}
1119 	return (vm_phys_fictitious_to_vm_page(pa));
1120 #else
1121 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined."
1122 #endif
1123 }
1124 
1125 /*
1126  *	vm_page_getfake:
1127  *
1128  *	Create a fictitious page with the specified physical address and
1129  *	memory attribute.  The memory attribute is the only the machine-
1130  *	dependent aspect of a fictitious page that must be initialized.
1131  */
1132 vm_page_t
1133 vm_page_getfake(vm_paddr_t paddr, vm_memattr_t memattr)
1134 {
1135 	vm_page_t m;
1136 
1137 	m = uma_zalloc(fakepg_zone, M_WAITOK | M_ZERO);
1138 	vm_page_initfake(m, paddr, memattr);
1139 	return (m);
1140 }
1141 
1142 void
1143 vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
1144 {
1145 
1146 	if ((m->flags & PG_FICTITIOUS) != 0) {
1147 		/*
1148 		 * The page's memattr might have changed since the
1149 		 * previous initialization.  Update the pmap to the
1150 		 * new memattr.
1151 		 */
1152 		goto memattr;
1153 	}
1154 	m->phys_addr = paddr;
1155 	m->queue = PQ_NONE;
1156 	/* Fictitious pages don't use "segind". */
1157 	m->flags = PG_FICTITIOUS;
1158 	/* Fictitious pages don't use "order" or "pool". */
1159 	m->oflags = VPO_UNMANAGED;
1160 	m->busy_lock = VPB_SINGLE_EXCLUSIVER;
1161 	/* Fictitious pages are unevictable. */
1162 	m->ref_count = 1;
1163 	pmap_page_init(m);
1164 memattr:
1165 	pmap_page_set_memattr(m, memattr);
1166 }
1167 
1168 /*
1169  *	vm_page_putfake:
1170  *
1171  *	Release a fictitious page.
1172  */
1173 void
1174 vm_page_putfake(vm_page_t m)
1175 {
1176 
1177 	KASSERT((m->oflags & VPO_UNMANAGED) != 0, ("managed %p", m));
1178 	KASSERT((m->flags & PG_FICTITIOUS) != 0,
1179 	    ("vm_page_putfake: bad page %p", m));
1180 	uma_zfree(fakepg_zone, m);
1181 }
1182 
1183 /*
1184  *	vm_page_updatefake:
1185  *
1186  *	Update the given fictitious page to the specified physical address and
1187  *	memory attribute.
1188  */
1189 void
1190 vm_page_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
1191 {
1192 
1193 	KASSERT((m->flags & PG_FICTITIOUS) != 0,
1194 	    ("vm_page_updatefake: bad page %p", m));
1195 	m->phys_addr = paddr;
1196 	pmap_page_set_memattr(m, memattr);
1197 }
1198 
1199 /*
1200  *	vm_page_free:
1201  *
1202  *	Free a page.
1203  */
1204 void
1205 vm_page_free(vm_page_t m)
1206 {
1207 
1208 	m->flags &= ~PG_ZERO;
1209 	vm_page_free_toq(m);
1210 }
1211 
1212 /*
1213  *	vm_page_free_zero:
1214  *
1215  *	Free a page to the zerod-pages queue
1216  */
1217 void
1218 vm_page_free_zero(vm_page_t m)
1219 {
1220 
1221 	m->flags |= PG_ZERO;
1222 	vm_page_free_toq(m);
1223 }
1224 
1225 /*
1226  * Unbusy and handle the page queueing for a page from a getpages request that
1227  * was optionally read ahead or behind.
1228  */
1229 void
1230 vm_page_readahead_finish(vm_page_t m)
1231 {
1232 
1233 	/* We shouldn't put invalid pages on queues. */
1234 	KASSERT(m->valid != 0, ("%s: %p is invalid", __func__, m));
1235 
1236 	/*
1237 	 * Since the page is not the actually needed one, whether it should
1238 	 * be activated or deactivated is not obvious.  Empirical results
1239 	 * have shown that deactivating the page is usually the best choice,
1240 	 * unless the page is wanted by another thread.
1241 	 */
1242 	vm_page_lock(m);
1243 	if ((m->busy_lock & VPB_BIT_WAITERS) != 0)
1244 		vm_page_activate(m);
1245 	else
1246 		vm_page_deactivate(m);
1247 	vm_page_unlock(m);
1248 	vm_page_xunbusy(m);
1249 }
1250 
1251 /*
1252  *	vm_page_sleep_if_busy:
1253  *
1254  *	Sleep and release the object lock if the page is busied.
1255  *	Returns TRUE if the thread slept.
1256  *
1257  *	The given page must be unlocked and object containing it must
1258  *	be locked.
1259  */
1260 int
1261 vm_page_sleep_if_busy(vm_page_t m, const char *msg)
1262 {
1263 	vm_object_t obj;
1264 
1265 	vm_page_lock_assert(m, MA_NOTOWNED);
1266 	VM_OBJECT_ASSERT_WLOCKED(m->object);
1267 
1268 	if (vm_page_busied(m)) {
1269 		/*
1270 		 * The page-specific object must be cached because page
1271 		 * identity can change during the sleep, causing the
1272 		 * re-lock of a different object.
1273 		 * It is assumed that a reference to the object is already
1274 		 * held by the callers.
1275 		 */
1276 		obj = m->object;
1277 		vm_page_busy_sleep(m, msg, false);
1278 		VM_OBJECT_WLOCK(obj);
1279 		return (TRUE);
1280 	}
1281 	return (FALSE);
1282 }
1283 
1284 /*
1285  *	vm_page_sleep_if_xbusy:
1286  *
1287  *	Sleep and release the object lock if the page is xbusied.
1288  *	Returns TRUE if the thread slept.
1289  *
1290  *	The given page must be unlocked and object containing it must
1291  *	be locked.
1292  */
1293 int
1294 vm_page_sleep_if_xbusy(vm_page_t m, const char *msg)
1295 {
1296 	vm_object_t obj;
1297 
1298 	vm_page_lock_assert(m, MA_NOTOWNED);
1299 	VM_OBJECT_ASSERT_WLOCKED(m->object);
1300 
1301 	if (vm_page_xbusied(m)) {
1302 		/*
1303 		 * The page-specific object must be cached because page
1304 		 * identity can change during the sleep, causing the
1305 		 * re-lock of a different object.
1306 		 * It is assumed that a reference to the object is already
1307 		 * held by the callers.
1308 		 */
1309 		obj = m->object;
1310 		vm_page_busy_sleep(m, msg, true);
1311 		VM_OBJECT_WLOCK(obj);
1312 		return (TRUE);
1313 	}
1314 	return (FALSE);
1315 }
1316 
1317 /*
1318  *	vm_page_dirty_KBI:		[ internal use only ]
1319  *
1320  *	Set all bits in the page's dirty field.
1321  *
1322  *	The object containing the specified page must be locked if the
1323  *	call is made from the machine-independent layer.
1324  *
1325  *	See vm_page_clear_dirty_mask().
1326  *
1327  *	This function should only be called by vm_page_dirty().
1328  */
1329 void
1330 vm_page_dirty_KBI(vm_page_t m)
1331 {
1332 
1333 	/* Refer to this operation by its public name. */
1334 	KASSERT(m->valid == VM_PAGE_BITS_ALL,
1335 	    ("vm_page_dirty: page is invalid!"));
1336 	m->dirty = VM_PAGE_BITS_ALL;
1337 }
1338 
1339 /*
1340  *	vm_page_insert:		[ internal use only ]
1341  *
1342  *	Inserts the given mem entry into the object and object list.
1343  *
1344  *	The object must be locked.
1345  */
1346 int
1347 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
1348 {
1349 	vm_page_t mpred;
1350 
1351 	VM_OBJECT_ASSERT_WLOCKED(object);
1352 	mpred = vm_radix_lookup_le(&object->rtree, pindex);
1353 	return (vm_page_insert_after(m, object, pindex, mpred));
1354 }
1355 
1356 /*
1357  *	vm_page_insert_after:
1358  *
1359  *	Inserts the page "m" into the specified object at offset "pindex".
1360  *
1361  *	The page "mpred" must immediately precede the offset "pindex" within
1362  *	the specified object.
1363  *
1364  *	The object must be locked.
1365  */
1366 static int
1367 vm_page_insert_after(vm_page_t m, vm_object_t object, vm_pindex_t pindex,
1368     vm_page_t mpred)
1369 {
1370 	vm_page_t msucc;
1371 
1372 	VM_OBJECT_ASSERT_WLOCKED(object);
1373 	KASSERT(m->object == NULL,
1374 	    ("vm_page_insert_after: page already inserted"));
1375 	if (mpred != NULL) {
1376 		KASSERT(mpred->object == object,
1377 		    ("vm_page_insert_after: object doesn't contain mpred"));
1378 		KASSERT(mpred->pindex < pindex,
1379 		    ("vm_page_insert_after: mpred doesn't precede pindex"));
1380 		msucc = TAILQ_NEXT(mpred, listq);
1381 	} else
1382 		msucc = TAILQ_FIRST(&object->memq);
1383 	if (msucc != NULL)
1384 		KASSERT(msucc->pindex > pindex,
1385 		    ("vm_page_insert_after: msucc doesn't succeed pindex"));
1386 
1387 	/*
1388 	 * Record the object/offset pair in this page.
1389 	 */
1390 	m->object = object;
1391 	m->pindex = pindex;
1392 	m->ref_count |= VPRC_OBJREF;
1393 
1394 	/*
1395 	 * Now link into the object's ordered list of backed pages.
1396 	 */
1397 	if (vm_radix_insert(&object->rtree, m)) {
1398 		m->object = NULL;
1399 		m->pindex = 0;
1400 		m->ref_count &= ~VPRC_OBJREF;
1401 		return (1);
1402 	}
1403 	vm_page_insert_radixdone(m, object, mpred);
1404 	return (0);
1405 }
1406 
1407 /*
1408  *	vm_page_insert_radixdone:
1409  *
1410  *	Complete page "m" insertion into the specified object after the
1411  *	radix trie hooking.
1412  *
1413  *	The page "mpred" must precede the offset "m->pindex" within the
1414  *	specified object.
1415  *
1416  *	The object must be locked.
1417  */
1418 static void
1419 vm_page_insert_radixdone(vm_page_t m, vm_object_t object, vm_page_t mpred)
1420 {
1421 
1422 	VM_OBJECT_ASSERT_WLOCKED(object);
1423 	KASSERT(object != NULL && m->object == object,
1424 	    ("vm_page_insert_radixdone: page %p has inconsistent object", m));
1425 	KASSERT((m->ref_count & VPRC_OBJREF) != 0,
1426 	    ("vm_page_insert_radixdone: page %p is missing object ref", m));
1427 	if (mpred != NULL) {
1428 		KASSERT(mpred->object == object,
1429 		    ("vm_page_insert_radixdone: object doesn't contain mpred"));
1430 		KASSERT(mpred->pindex < m->pindex,
1431 		    ("vm_page_insert_radixdone: mpred doesn't precede pindex"));
1432 	}
1433 
1434 	if (mpred != NULL)
1435 		TAILQ_INSERT_AFTER(&object->memq, mpred, m, listq);
1436 	else
1437 		TAILQ_INSERT_HEAD(&object->memq, m, listq);
1438 
1439 	/*
1440 	 * Show that the object has one more resident page.
1441 	 */
1442 	object->resident_page_count++;
1443 
1444 	/*
1445 	 * Hold the vnode until the last page is released.
1446 	 */
1447 	if (object->resident_page_count == 1 && object->type == OBJT_VNODE)
1448 		vhold(object->handle);
1449 
1450 	/*
1451 	 * Since we are inserting a new and possibly dirty page,
1452 	 * update the object's OBJ_MIGHTBEDIRTY flag.
1453 	 */
1454 	if (pmap_page_is_write_mapped(m))
1455 		vm_object_set_writeable_dirty(object);
1456 }
1457 
1458 /*
1459  * Do the work to remove a page from its object.  The caller is responsible for
1460  * updating the page's fields to reflect this removal.
1461  */
1462 static void
1463 vm_page_object_remove(vm_page_t m)
1464 {
1465 	vm_object_t object;
1466 	vm_page_t mrem;
1467 
1468 	object = m->object;
1469 	VM_OBJECT_ASSERT_WLOCKED(object);
1470 	KASSERT((m->ref_count & VPRC_OBJREF) != 0,
1471 	    ("page %p is missing its object ref", m));
1472 	if (vm_page_xbusied(m))
1473 		vm_page_xunbusy(m);
1474 	mrem = vm_radix_remove(&object->rtree, m->pindex);
1475 	KASSERT(mrem == m, ("removed page %p, expected page %p", mrem, m));
1476 
1477 	/*
1478 	 * Now remove from the object's list of backed pages.
1479 	 */
1480 	TAILQ_REMOVE(&object->memq, m, listq);
1481 
1482 	/*
1483 	 * And show that the object has one fewer resident page.
1484 	 */
1485 	object->resident_page_count--;
1486 
1487 	/*
1488 	 * The vnode may now be recycled.
1489 	 */
1490 	if (object->resident_page_count == 0 && object->type == OBJT_VNODE)
1491 		vdrop(object->handle);
1492 }
1493 
1494 /*
1495  *	vm_page_remove:
1496  *
1497  *	Removes the specified page from its containing object, but does not
1498  *	invalidate any backing storage.  Returns true if the object's reference
1499  *	was the last reference to the page, and false otherwise.
1500  *
1501  *	The object must be locked.
1502  */
1503 bool
1504 vm_page_remove(vm_page_t m)
1505 {
1506 
1507 	vm_page_object_remove(m);
1508 	m->object = NULL;
1509 	return (vm_page_drop(m, VPRC_OBJREF) == VPRC_OBJREF);
1510 }
1511 
1512 /*
1513  *	vm_page_lookup:
1514  *
1515  *	Returns the page associated with the object/offset
1516  *	pair specified; if none is found, NULL is returned.
1517  *
1518  *	The object must be locked.
1519  */
1520 vm_page_t
1521 vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
1522 {
1523 
1524 	VM_OBJECT_ASSERT_LOCKED(object);
1525 	return (vm_radix_lookup(&object->rtree, pindex));
1526 }
1527 
1528 /*
1529  *	vm_page_find_least:
1530  *
1531  *	Returns the page associated with the object with least pindex
1532  *	greater than or equal to the parameter pindex, or NULL.
1533  *
1534  *	The object must be locked.
1535  */
1536 vm_page_t
1537 vm_page_find_least(vm_object_t object, vm_pindex_t pindex)
1538 {
1539 	vm_page_t m;
1540 
1541 	VM_OBJECT_ASSERT_LOCKED(object);
1542 	if ((m = TAILQ_FIRST(&object->memq)) != NULL && m->pindex < pindex)
1543 		m = vm_radix_lookup_ge(&object->rtree, pindex);
1544 	return (m);
1545 }
1546 
1547 /*
1548  * Returns the given page's successor (by pindex) within the object if it is
1549  * resident; if none is found, NULL is returned.
1550  *
1551  * The object must be locked.
1552  */
1553 vm_page_t
1554 vm_page_next(vm_page_t m)
1555 {
1556 	vm_page_t next;
1557 
1558 	VM_OBJECT_ASSERT_LOCKED(m->object);
1559 	if ((next = TAILQ_NEXT(m, listq)) != NULL) {
1560 		MPASS(next->object == m->object);
1561 		if (next->pindex != m->pindex + 1)
1562 			next = NULL;
1563 	}
1564 	return (next);
1565 }
1566 
1567 /*
1568  * Returns the given page's predecessor (by pindex) within the object if it is
1569  * resident; if none is found, NULL is returned.
1570  *
1571  * The object must be locked.
1572  */
1573 vm_page_t
1574 vm_page_prev(vm_page_t m)
1575 {
1576 	vm_page_t prev;
1577 
1578 	VM_OBJECT_ASSERT_LOCKED(m->object);
1579 	if ((prev = TAILQ_PREV(m, pglist, listq)) != NULL) {
1580 		MPASS(prev->object == m->object);
1581 		if (prev->pindex != m->pindex - 1)
1582 			prev = NULL;
1583 	}
1584 	return (prev);
1585 }
1586 
1587 /*
1588  * Uses the page mnew as a replacement for an existing page at index
1589  * pindex which must be already present in the object.
1590  */
1591 vm_page_t
1592 vm_page_replace(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex)
1593 {
1594 	vm_page_t mold;
1595 
1596 	VM_OBJECT_ASSERT_WLOCKED(object);
1597 	KASSERT(mnew->object == NULL && (mnew->ref_count & VPRC_OBJREF) == 0,
1598 	    ("vm_page_replace: page %p already in object", mnew));
1599 
1600 	/*
1601 	 * This function mostly follows vm_page_insert() and
1602 	 * vm_page_remove() without the radix, object count and vnode
1603 	 * dance.  Double check such functions for more comments.
1604 	 */
1605 
1606 	mnew->object = object;
1607 	mnew->pindex = pindex;
1608 	atomic_set_int(&mnew->ref_count, VPRC_OBJREF);
1609 	mold = vm_radix_replace(&object->rtree, mnew);
1610 	KASSERT(mold->queue == PQ_NONE,
1611 	    ("vm_page_replace: old page %p is on a paging queue", mold));
1612 
1613 	/* Keep the resident page list in sorted order. */
1614 	TAILQ_INSERT_AFTER(&object->memq, mold, mnew, listq);
1615 	TAILQ_REMOVE(&object->memq, mold, listq);
1616 
1617 	mold->object = NULL;
1618 	atomic_clear_int(&mold->ref_count, VPRC_OBJREF);
1619 	vm_page_xunbusy(mold);
1620 
1621 	/*
1622 	 * The object's resident_page_count does not change because we have
1623 	 * swapped one page for another, but OBJ_MIGHTBEDIRTY.
1624 	 */
1625 	if (pmap_page_is_write_mapped(mnew))
1626 		vm_object_set_writeable_dirty(object);
1627 	return (mold);
1628 }
1629 
1630 /*
1631  *	vm_page_rename:
1632  *
1633  *	Move the given memory entry from its
1634  *	current object to the specified target object/offset.
1635  *
1636  *	Note: swap associated with the page must be invalidated by the move.  We
1637  *	      have to do this for several reasons:  (1) we aren't freeing the
1638  *	      page, (2) we are dirtying the page, (3) the VM system is probably
1639  *	      moving the page from object A to B, and will then later move
1640  *	      the backing store from A to B and we can't have a conflict.
1641  *
1642  *	Note: we *always* dirty the page.  It is necessary both for the
1643  *	      fact that we moved it, and because we may be invalidating
1644  *	      swap.
1645  *
1646  *	The objects must be locked.
1647  */
1648 int
1649 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
1650 {
1651 	vm_page_t mpred;
1652 	vm_pindex_t opidx;
1653 
1654 	VM_OBJECT_ASSERT_WLOCKED(new_object);
1655 
1656 	KASSERT(m->ref_count != 0, ("vm_page_rename: page %p has no refs", m));
1657 	mpred = vm_radix_lookup_le(&new_object->rtree, new_pindex);
1658 	KASSERT(mpred == NULL || mpred->pindex != new_pindex,
1659 	    ("vm_page_rename: pindex already renamed"));
1660 
1661 	/*
1662 	 * Create a custom version of vm_page_insert() which does not depend
1663 	 * by m_prev and can cheat on the implementation aspects of the
1664 	 * function.
1665 	 */
1666 	opidx = m->pindex;
1667 	m->pindex = new_pindex;
1668 	if (vm_radix_insert(&new_object->rtree, m)) {
1669 		m->pindex = opidx;
1670 		return (1);
1671 	}
1672 
1673 	/*
1674 	 * The operation cannot fail anymore.  The removal must happen before
1675 	 * the listq iterator is tainted.
1676 	 */
1677 	m->pindex = opidx;
1678 	vm_page_object_remove(m);
1679 
1680 	/* Return back to the new pindex to complete vm_page_insert(). */
1681 	m->pindex = new_pindex;
1682 	m->object = new_object;
1683 
1684 	vm_page_insert_radixdone(m, new_object, mpred);
1685 	vm_page_dirty(m);
1686 	return (0);
1687 }
1688 
1689 /*
1690  *	vm_page_alloc:
1691  *
1692  *	Allocate and return a page that is associated with the specified
1693  *	object and offset pair.  By default, this page is exclusive busied.
1694  *
1695  *	The caller must always specify an allocation class.
1696  *
1697  *	allocation classes:
1698  *	VM_ALLOC_NORMAL		normal process request
1699  *	VM_ALLOC_SYSTEM		system *really* needs a page
1700  *	VM_ALLOC_INTERRUPT	interrupt time request
1701  *
1702  *	optional allocation flags:
1703  *	VM_ALLOC_COUNT(number)	the number of additional pages that the caller
1704  *				intends to allocate
1705  *	VM_ALLOC_NOBUSY		do not exclusive busy the page
1706  *	VM_ALLOC_NODUMP		do not include the page in a kernel core dump
1707  *	VM_ALLOC_NOOBJ		page is not associated with an object and
1708  *				should not be exclusive busy
1709  *	VM_ALLOC_SBUSY		shared busy the allocated page
1710  *	VM_ALLOC_WIRED		wire the allocated page
1711  *	VM_ALLOC_ZERO		prefer a zeroed page
1712  */
1713 vm_page_t
1714 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req)
1715 {
1716 
1717 	return (vm_page_alloc_after(object, pindex, req, object != NULL ?
1718 	    vm_radix_lookup_le(&object->rtree, pindex) : NULL));
1719 }
1720 
1721 vm_page_t
1722 vm_page_alloc_domain(vm_object_t object, vm_pindex_t pindex, int domain,
1723     int req)
1724 {
1725 
1726 	return (vm_page_alloc_domain_after(object, pindex, domain, req,
1727 	    object != NULL ? vm_radix_lookup_le(&object->rtree, pindex) :
1728 	    NULL));
1729 }
1730 
1731 /*
1732  * Allocate a page in the specified object with the given page index.  To
1733  * optimize insertion of the page into the object, the caller must also specifiy
1734  * the resident page in the object with largest index smaller than the given
1735  * page index, or NULL if no such page exists.
1736  */
1737 vm_page_t
1738 vm_page_alloc_after(vm_object_t object, vm_pindex_t pindex,
1739     int req, vm_page_t mpred)
1740 {
1741 	struct vm_domainset_iter di;
1742 	vm_page_t m;
1743 	int domain;
1744 
1745 	vm_domainset_iter_page_init(&di, object, pindex, &domain, &req);
1746 	do {
1747 		m = vm_page_alloc_domain_after(object, pindex, domain, req,
1748 		    mpred);
1749 		if (m != NULL)
1750 			break;
1751 	} while (vm_domainset_iter_page(&di, object, &domain) == 0);
1752 
1753 	return (m);
1754 }
1755 
1756 /*
1757  * Returns true if the number of free pages exceeds the minimum
1758  * for the request class and false otherwise.
1759  */
1760 int
1761 vm_domain_allocate(struct vm_domain *vmd, int req, int npages)
1762 {
1763 	u_int limit, old, new;
1764 
1765 	req = req & VM_ALLOC_CLASS_MASK;
1766 
1767 	/*
1768 	 * The page daemon is allowed to dig deeper into the free page list.
1769 	 */
1770 	if (curproc == pageproc && req != VM_ALLOC_INTERRUPT)
1771 		req = VM_ALLOC_SYSTEM;
1772 	if (req == VM_ALLOC_INTERRUPT)
1773 		limit = 0;
1774 	else if (req == VM_ALLOC_SYSTEM)
1775 		limit = vmd->vmd_interrupt_free_min;
1776 	else
1777 		limit = vmd->vmd_free_reserved;
1778 
1779 	/*
1780 	 * Attempt to reserve the pages.  Fail if we're below the limit.
1781 	 */
1782 	limit += npages;
1783 	old = vmd->vmd_free_count;
1784 	do {
1785 		if (old < limit)
1786 			return (0);
1787 		new = old - npages;
1788 	} while (atomic_fcmpset_int(&vmd->vmd_free_count, &old, new) == 0);
1789 
1790 	/* Wake the page daemon if we've crossed the threshold. */
1791 	if (vm_paging_needed(vmd, new) && !vm_paging_needed(vmd, old))
1792 		pagedaemon_wakeup(vmd->vmd_domain);
1793 
1794 	/* Only update bitsets on transitions. */
1795 	if ((old >= vmd->vmd_free_min && new < vmd->vmd_free_min) ||
1796 	    (old >= vmd->vmd_free_severe && new < vmd->vmd_free_severe))
1797 		vm_domain_set(vmd);
1798 
1799 	return (1);
1800 }
1801 
1802 vm_page_t
1803 vm_page_alloc_domain_after(vm_object_t object, vm_pindex_t pindex, int domain,
1804     int req, vm_page_t mpred)
1805 {
1806 	struct vm_domain *vmd;
1807 	vm_page_t m;
1808 	int flags, pool;
1809 
1810 	KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0) &&
1811 	    (object != NULL || (req & VM_ALLOC_SBUSY) == 0) &&
1812 	    ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) !=
1813 	    (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)),
1814 	    ("inconsistent object(%p)/req(%x)", object, req));
1815 	KASSERT(object == NULL || (req & VM_ALLOC_WAITOK) == 0,
1816 	    ("Can't sleep and retry object insertion."));
1817 	KASSERT(mpred == NULL || mpred->pindex < pindex,
1818 	    ("mpred %p doesn't precede pindex 0x%jx", mpred,
1819 	    (uintmax_t)pindex));
1820 	if (object != NULL)
1821 		VM_OBJECT_ASSERT_WLOCKED(object);
1822 
1823 	flags = 0;
1824 	m = NULL;
1825 	pool = object != NULL ? VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT;
1826 again:
1827 #if VM_NRESERVLEVEL > 0
1828 	/*
1829 	 * Can we allocate the page from a reservation?
1830 	 */
1831 	if (vm_object_reserv(object) &&
1832 	    (m = vm_reserv_alloc_page(object, pindex, domain, req, mpred)) !=
1833 	    NULL) {
1834 		domain = vm_phys_domain(m);
1835 		vmd = VM_DOMAIN(domain);
1836 		goto found;
1837 	}
1838 #endif
1839 	vmd = VM_DOMAIN(domain);
1840 	if (vmd->vmd_pgcache[pool].zone != NULL) {
1841 		m = uma_zalloc(vmd->vmd_pgcache[pool].zone, M_NOWAIT);
1842 		if (m != NULL) {
1843 			flags |= PG_PCPU_CACHE;
1844 			goto found;
1845 		}
1846 	}
1847 	if (vm_domain_allocate(vmd, req, 1)) {
1848 		/*
1849 		 * If not, allocate it from the free page queues.
1850 		 */
1851 		vm_domain_free_lock(vmd);
1852 		m = vm_phys_alloc_pages(domain, pool, 0);
1853 		vm_domain_free_unlock(vmd);
1854 		if (m == NULL) {
1855 			vm_domain_freecnt_inc(vmd, 1);
1856 #if VM_NRESERVLEVEL > 0
1857 			if (vm_reserv_reclaim_inactive(domain))
1858 				goto again;
1859 #endif
1860 		}
1861 	}
1862 	if (m == NULL) {
1863 		/*
1864 		 * Not allocatable, give up.
1865 		 */
1866 		if (vm_domain_alloc_fail(vmd, object, req))
1867 			goto again;
1868 		return (NULL);
1869 	}
1870 
1871 	/*
1872 	 * At this point we had better have found a good page.
1873 	 */
1874 found:
1875 	vm_page_dequeue(m);
1876 	vm_page_alloc_check(m);
1877 
1878 	/*
1879 	 * Initialize the page.  Only the PG_ZERO flag is inherited.
1880 	 */
1881 	if ((req & VM_ALLOC_ZERO) != 0)
1882 		flags |= (m->flags & PG_ZERO);
1883 	if ((req & VM_ALLOC_NODUMP) != 0)
1884 		flags |= PG_NODUMP;
1885 	m->flags = flags;
1886 	m->aflags = 0;
1887 	m->oflags = object == NULL || (object->flags & OBJ_UNMANAGED) != 0 ?
1888 	    VPO_UNMANAGED : 0;
1889 	m->busy_lock = VPB_UNBUSIED;
1890 	if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ | VM_ALLOC_SBUSY)) == 0)
1891 		m->busy_lock = VPB_SINGLE_EXCLUSIVER;
1892 	if ((req & VM_ALLOC_SBUSY) != 0)
1893 		m->busy_lock = VPB_SHARERS_WORD(1);
1894 	if (req & VM_ALLOC_WIRED) {
1895 		/*
1896 		 * The page lock is not required for wiring a page until that
1897 		 * page is inserted into the object.
1898 		 */
1899 		vm_wire_add(1);
1900 		m->ref_count = 1;
1901 	}
1902 	m->act_count = 0;
1903 
1904 	if (object != NULL) {
1905 		if (vm_page_insert_after(m, object, pindex, mpred)) {
1906 			if (req & VM_ALLOC_WIRED) {
1907 				vm_wire_sub(1);
1908 				m->ref_count = 0;
1909 			}
1910 			KASSERT(m->object == NULL, ("page %p has object", m));
1911 			m->oflags = VPO_UNMANAGED;
1912 			m->busy_lock = VPB_UNBUSIED;
1913 			/* Don't change PG_ZERO. */
1914 			vm_page_free_toq(m);
1915 			if (req & VM_ALLOC_WAITFAIL) {
1916 				VM_OBJECT_WUNLOCK(object);
1917 				vm_radix_wait();
1918 				VM_OBJECT_WLOCK(object);
1919 			}
1920 			return (NULL);
1921 		}
1922 
1923 		/* Ignore device objects; the pager sets "memattr" for them. */
1924 		if (object->memattr != VM_MEMATTR_DEFAULT &&
1925 		    (object->flags & OBJ_FICTITIOUS) == 0)
1926 			pmap_page_set_memattr(m, object->memattr);
1927 	} else
1928 		m->pindex = pindex;
1929 
1930 	return (m);
1931 }
1932 
1933 /*
1934  *	vm_page_alloc_contig:
1935  *
1936  *	Allocate a contiguous set of physical pages of the given size "npages"
1937  *	from the free lists.  All of the physical pages must be at or above
1938  *	the given physical address "low" and below the given physical address
1939  *	"high".  The given value "alignment" determines the alignment of the
1940  *	first physical page in the set.  If the given value "boundary" is
1941  *	non-zero, then the set of physical pages cannot cross any physical
1942  *	address boundary that is a multiple of that value.  Both "alignment"
1943  *	and "boundary" must be a power of two.
1944  *
1945  *	If the specified memory attribute, "memattr", is VM_MEMATTR_DEFAULT,
1946  *	then the memory attribute setting for the physical pages is configured
1947  *	to the object's memory attribute setting.  Otherwise, the memory
1948  *	attribute setting for the physical pages is configured to "memattr",
1949  *	overriding the object's memory attribute setting.  However, if the
1950  *	object's memory attribute setting is not VM_MEMATTR_DEFAULT, then the
1951  *	memory attribute setting for the physical pages cannot be configured
1952  *	to VM_MEMATTR_DEFAULT.
1953  *
1954  *	The specified object may not contain fictitious pages.
1955  *
1956  *	The caller must always specify an allocation class.
1957  *
1958  *	allocation classes:
1959  *	VM_ALLOC_NORMAL		normal process request
1960  *	VM_ALLOC_SYSTEM		system *really* needs a page
1961  *	VM_ALLOC_INTERRUPT	interrupt time request
1962  *
1963  *	optional allocation flags:
1964  *	VM_ALLOC_NOBUSY		do not exclusive busy the page
1965  *	VM_ALLOC_NODUMP		do not include the page in a kernel core dump
1966  *	VM_ALLOC_NOOBJ		page is not associated with an object and
1967  *				should not be exclusive busy
1968  *	VM_ALLOC_SBUSY		shared busy the allocated page
1969  *	VM_ALLOC_WIRED		wire the allocated page
1970  *	VM_ALLOC_ZERO		prefer a zeroed page
1971  */
1972 vm_page_t
1973 vm_page_alloc_contig(vm_object_t object, vm_pindex_t pindex, int req,
1974     u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment,
1975     vm_paddr_t boundary, vm_memattr_t memattr)
1976 {
1977 	struct vm_domainset_iter di;
1978 	vm_page_t m;
1979 	int domain;
1980 
1981 	vm_domainset_iter_page_init(&di, object, pindex, &domain, &req);
1982 	do {
1983 		m = vm_page_alloc_contig_domain(object, pindex, domain, req,
1984 		    npages, low, high, alignment, boundary, memattr);
1985 		if (m != NULL)
1986 			break;
1987 	} while (vm_domainset_iter_page(&di, object, &domain) == 0);
1988 
1989 	return (m);
1990 }
1991 
1992 vm_page_t
1993 vm_page_alloc_contig_domain(vm_object_t object, vm_pindex_t pindex, int domain,
1994     int req, u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment,
1995     vm_paddr_t boundary, vm_memattr_t memattr)
1996 {
1997 	struct vm_domain *vmd;
1998 	vm_page_t m, m_ret, mpred;
1999 	u_int busy_lock, flags, oflags;
2000 
2001 	mpred = NULL;	/* XXX: pacify gcc */
2002 	KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0) &&
2003 	    (object != NULL || (req & VM_ALLOC_SBUSY) == 0) &&
2004 	    ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) !=
2005 	    (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)),
2006 	    ("vm_page_alloc_contig: inconsistent object(%p)/req(%x)", object,
2007 	    req));
2008 	KASSERT(object == NULL || (req & VM_ALLOC_WAITOK) == 0,
2009 	    ("Can't sleep and retry object insertion."));
2010 	if (object != NULL) {
2011 		VM_OBJECT_ASSERT_WLOCKED(object);
2012 		KASSERT((object->flags & OBJ_FICTITIOUS) == 0,
2013 		    ("vm_page_alloc_contig: object %p has fictitious pages",
2014 		    object));
2015 	}
2016 	KASSERT(npages > 0, ("vm_page_alloc_contig: npages is zero"));
2017 
2018 	if (object != NULL) {
2019 		mpred = vm_radix_lookup_le(&object->rtree, pindex);
2020 		KASSERT(mpred == NULL || mpred->pindex != pindex,
2021 		    ("vm_page_alloc_contig: pindex already allocated"));
2022 	}
2023 
2024 	/*
2025 	 * Can we allocate the pages without the number of free pages falling
2026 	 * below the lower bound for the allocation class?
2027 	 */
2028 	m_ret = NULL;
2029 again:
2030 #if VM_NRESERVLEVEL > 0
2031 	/*
2032 	 * Can we allocate the pages from a reservation?
2033 	 */
2034 	if (vm_object_reserv(object) &&
2035 	    (m_ret = vm_reserv_alloc_contig(object, pindex, domain, req,
2036 	    mpred, npages, low, high, alignment, boundary)) != NULL) {
2037 		domain = vm_phys_domain(m_ret);
2038 		vmd = VM_DOMAIN(domain);
2039 		goto found;
2040 	}
2041 #endif
2042 	vmd = VM_DOMAIN(domain);
2043 	if (vm_domain_allocate(vmd, req, npages)) {
2044 		/*
2045 		 * allocate them from the free page queues.
2046 		 */
2047 		vm_domain_free_lock(vmd);
2048 		m_ret = vm_phys_alloc_contig(domain, npages, low, high,
2049 		    alignment, boundary);
2050 		vm_domain_free_unlock(vmd);
2051 		if (m_ret == NULL) {
2052 			vm_domain_freecnt_inc(vmd, npages);
2053 #if VM_NRESERVLEVEL > 0
2054 			if (vm_reserv_reclaim_contig(domain, npages, low,
2055 			    high, alignment, boundary))
2056 				goto again;
2057 #endif
2058 		}
2059 	}
2060 	if (m_ret == NULL) {
2061 		if (vm_domain_alloc_fail(vmd, object, req))
2062 			goto again;
2063 		return (NULL);
2064 	}
2065 #if VM_NRESERVLEVEL > 0
2066 found:
2067 #endif
2068 	for (m = m_ret; m < &m_ret[npages]; m++) {
2069 		vm_page_dequeue(m);
2070 		vm_page_alloc_check(m);
2071 	}
2072 
2073 	/*
2074 	 * Initialize the pages.  Only the PG_ZERO flag is inherited.
2075 	 */
2076 	flags = 0;
2077 	if ((req & VM_ALLOC_ZERO) != 0)
2078 		flags = PG_ZERO;
2079 	if ((req & VM_ALLOC_NODUMP) != 0)
2080 		flags |= PG_NODUMP;
2081 	oflags = object == NULL || (object->flags & OBJ_UNMANAGED) != 0 ?
2082 	    VPO_UNMANAGED : 0;
2083 	busy_lock = VPB_UNBUSIED;
2084 	if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ | VM_ALLOC_SBUSY)) == 0)
2085 		busy_lock = VPB_SINGLE_EXCLUSIVER;
2086 	if ((req & VM_ALLOC_SBUSY) != 0)
2087 		busy_lock = VPB_SHARERS_WORD(1);
2088 	if ((req & VM_ALLOC_WIRED) != 0)
2089 		vm_wire_add(npages);
2090 	if (object != NULL) {
2091 		if (object->memattr != VM_MEMATTR_DEFAULT &&
2092 		    memattr == VM_MEMATTR_DEFAULT)
2093 			memattr = object->memattr;
2094 	}
2095 	for (m = m_ret; m < &m_ret[npages]; m++) {
2096 		m->aflags = 0;
2097 		m->flags = (m->flags | PG_NODUMP) & flags;
2098 		m->busy_lock = busy_lock;
2099 		if ((req & VM_ALLOC_WIRED) != 0)
2100 			m->ref_count = 1;
2101 		m->act_count = 0;
2102 		m->oflags = oflags;
2103 		if (object != NULL) {
2104 			if (vm_page_insert_after(m, object, pindex, mpred)) {
2105 				if ((req & VM_ALLOC_WIRED) != 0)
2106 					vm_wire_sub(npages);
2107 				KASSERT(m->object == NULL,
2108 				    ("page %p has object", m));
2109 				mpred = m;
2110 				for (m = m_ret; m < &m_ret[npages]; m++) {
2111 					if (m <= mpred &&
2112 					    (req & VM_ALLOC_WIRED) != 0)
2113 						m->ref_count = 0;
2114 					m->oflags = VPO_UNMANAGED;
2115 					m->busy_lock = VPB_UNBUSIED;
2116 					/* Don't change PG_ZERO. */
2117 					vm_page_free_toq(m);
2118 				}
2119 				if (req & VM_ALLOC_WAITFAIL) {
2120 					VM_OBJECT_WUNLOCK(object);
2121 					vm_radix_wait();
2122 					VM_OBJECT_WLOCK(object);
2123 				}
2124 				return (NULL);
2125 			}
2126 			mpred = m;
2127 		} else
2128 			m->pindex = pindex;
2129 		if (memattr != VM_MEMATTR_DEFAULT)
2130 			pmap_page_set_memattr(m, memattr);
2131 		pindex++;
2132 	}
2133 	return (m_ret);
2134 }
2135 
2136 /*
2137  * Check a page that has been freshly dequeued from a freelist.
2138  */
2139 static void
2140 vm_page_alloc_check(vm_page_t m)
2141 {
2142 
2143 	KASSERT(m->object == NULL, ("page %p has object", m));
2144 	KASSERT(m->queue == PQ_NONE && (m->aflags & PGA_QUEUE_STATE_MASK) == 0,
2145 	    ("page %p has unexpected queue %d, flags %#x",
2146 	    m, m->queue, (m->aflags & PGA_QUEUE_STATE_MASK)));
2147 	KASSERT(m->ref_count == 0, ("page %p has references", m));
2148 	KASSERT(!vm_page_busied(m), ("page %p is busy", m));
2149 	KASSERT(m->dirty == 0, ("page %p is dirty", m));
2150 	KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT,
2151 	    ("page %p has unexpected memattr %d",
2152 	    m, pmap_page_get_memattr(m)));
2153 	KASSERT(m->valid == 0, ("free page %p is valid", m));
2154 }
2155 
2156 /*
2157  * 	vm_page_alloc_freelist:
2158  *
2159  *	Allocate a physical page from the specified free page list.
2160  *
2161  *	The caller must always specify an allocation class.
2162  *
2163  *	allocation classes:
2164  *	VM_ALLOC_NORMAL		normal process request
2165  *	VM_ALLOC_SYSTEM		system *really* needs a page
2166  *	VM_ALLOC_INTERRUPT	interrupt time request
2167  *
2168  *	optional allocation flags:
2169  *	VM_ALLOC_COUNT(number)	the number of additional pages that the caller
2170  *				intends to allocate
2171  *	VM_ALLOC_WIRED		wire the allocated page
2172  *	VM_ALLOC_ZERO		prefer a zeroed page
2173  */
2174 vm_page_t
2175 vm_page_alloc_freelist(int freelist, int req)
2176 {
2177 	struct vm_domainset_iter di;
2178 	vm_page_t m;
2179 	int domain;
2180 
2181 	vm_domainset_iter_page_init(&di, NULL, 0, &domain, &req);
2182 	do {
2183 		m = vm_page_alloc_freelist_domain(domain, freelist, req);
2184 		if (m != NULL)
2185 			break;
2186 	} while (vm_domainset_iter_page(&di, NULL, &domain) == 0);
2187 
2188 	return (m);
2189 }
2190 
2191 vm_page_t
2192 vm_page_alloc_freelist_domain(int domain, int freelist, int req)
2193 {
2194 	struct vm_domain *vmd;
2195 	vm_page_t m;
2196 	u_int flags;
2197 
2198 	m = NULL;
2199 	vmd = VM_DOMAIN(domain);
2200 again:
2201 	if (vm_domain_allocate(vmd, req, 1)) {
2202 		vm_domain_free_lock(vmd);
2203 		m = vm_phys_alloc_freelist_pages(domain, freelist,
2204 		    VM_FREEPOOL_DIRECT, 0);
2205 		vm_domain_free_unlock(vmd);
2206 		if (m == NULL)
2207 			vm_domain_freecnt_inc(vmd, 1);
2208 	}
2209 	if (m == NULL) {
2210 		if (vm_domain_alloc_fail(vmd, NULL, req))
2211 			goto again;
2212 		return (NULL);
2213 	}
2214 	vm_page_dequeue(m);
2215 	vm_page_alloc_check(m);
2216 
2217 	/*
2218 	 * Initialize the page.  Only the PG_ZERO flag is inherited.
2219 	 */
2220 	m->aflags = 0;
2221 	flags = 0;
2222 	if ((req & VM_ALLOC_ZERO) != 0)
2223 		flags = PG_ZERO;
2224 	m->flags &= flags;
2225 	if ((req & VM_ALLOC_WIRED) != 0) {
2226 		/*
2227 		 * The page lock is not required for wiring a page that does
2228 		 * not belong to an object.
2229 		 */
2230 		vm_wire_add(1);
2231 		m->ref_count = 1;
2232 	}
2233 	/* Unmanaged pages don't use "act_count". */
2234 	m->oflags = VPO_UNMANAGED;
2235 	return (m);
2236 }
2237 
2238 static int
2239 vm_page_zone_import(void *arg, void **store, int cnt, int domain, int flags)
2240 {
2241 	struct vm_domain *vmd;
2242 	struct vm_pgcache *pgcache;
2243 	int i;
2244 
2245 	pgcache = arg;
2246 	vmd = VM_DOMAIN(pgcache->domain);
2247 	/* Only import if we can bring in a full bucket. */
2248 	if (cnt == 1 || !vm_domain_allocate(vmd, VM_ALLOC_NORMAL, cnt))
2249 		return (0);
2250 	domain = vmd->vmd_domain;
2251 	vm_domain_free_lock(vmd);
2252 	i = vm_phys_alloc_npages(domain, pgcache->pool, cnt,
2253 	    (vm_page_t *)store);
2254 	vm_domain_free_unlock(vmd);
2255 	if (cnt != i)
2256 		vm_domain_freecnt_inc(vmd, cnt - i);
2257 
2258 	return (i);
2259 }
2260 
2261 static void
2262 vm_page_zone_release(void *arg, void **store, int cnt)
2263 {
2264 	struct vm_domain *vmd;
2265 	struct vm_pgcache *pgcache;
2266 	vm_page_t m;
2267 	int i;
2268 
2269 	pgcache = arg;
2270 	vmd = VM_DOMAIN(pgcache->domain);
2271 	vm_domain_free_lock(vmd);
2272 	for (i = 0; i < cnt; i++) {
2273 		m = (vm_page_t)store[i];
2274 		vm_phys_free_pages(m, 0);
2275 	}
2276 	vm_domain_free_unlock(vmd);
2277 	vm_domain_freecnt_inc(vmd, cnt);
2278 }
2279 
2280 #define	VPSC_ANY	0	/* No restrictions. */
2281 #define	VPSC_NORESERV	1	/* Skip reservations; implies VPSC_NOSUPER. */
2282 #define	VPSC_NOSUPER	2	/* Skip superpages. */
2283 
2284 /*
2285  *	vm_page_scan_contig:
2286  *
2287  *	Scan vm_page_array[] between the specified entries "m_start" and
2288  *	"m_end" for a run of contiguous physical pages that satisfy the
2289  *	specified conditions, and return the lowest page in the run.  The
2290  *	specified "alignment" determines the alignment of the lowest physical
2291  *	page in the run.  If the specified "boundary" is non-zero, then the
2292  *	run of physical pages cannot span a physical address that is a
2293  *	multiple of "boundary".
2294  *
2295  *	"m_end" is never dereferenced, so it need not point to a vm_page
2296  *	structure within vm_page_array[].
2297  *
2298  *	"npages" must be greater than zero.  "m_start" and "m_end" must not
2299  *	span a hole (or discontiguity) in the physical address space.  Both
2300  *	"alignment" and "boundary" must be a power of two.
2301  */
2302 vm_page_t
2303 vm_page_scan_contig(u_long npages, vm_page_t m_start, vm_page_t m_end,
2304     u_long alignment, vm_paddr_t boundary, int options)
2305 {
2306 	struct mtx *m_mtx;
2307 	vm_object_t object;
2308 	vm_paddr_t pa;
2309 	vm_page_t m, m_run;
2310 #if VM_NRESERVLEVEL > 0
2311 	int level;
2312 #endif
2313 	int m_inc, order, run_ext, run_len;
2314 
2315 	KASSERT(npages > 0, ("npages is 0"));
2316 	KASSERT(powerof2(alignment), ("alignment is not a power of 2"));
2317 	KASSERT(powerof2(boundary), ("boundary is not a power of 2"));
2318 	m_run = NULL;
2319 	run_len = 0;
2320 	m_mtx = NULL;
2321 	for (m = m_start; m < m_end && run_len < npages; m += m_inc) {
2322 		KASSERT((m->flags & PG_MARKER) == 0,
2323 		    ("page %p is PG_MARKER", m));
2324 		KASSERT((m->flags & PG_FICTITIOUS) == 0 || m->ref_count >= 1,
2325 		    ("fictitious page %p has invalid ref count", m));
2326 
2327 		/*
2328 		 * If the current page would be the start of a run, check its
2329 		 * physical address against the end, alignment, and boundary
2330 		 * conditions.  If it doesn't satisfy these conditions, either
2331 		 * terminate the scan or advance to the next page that
2332 		 * satisfies the failed condition.
2333 		 */
2334 		if (run_len == 0) {
2335 			KASSERT(m_run == NULL, ("m_run != NULL"));
2336 			if (m + npages > m_end)
2337 				break;
2338 			pa = VM_PAGE_TO_PHYS(m);
2339 			if ((pa & (alignment - 1)) != 0) {
2340 				m_inc = atop(roundup2(pa, alignment) - pa);
2341 				continue;
2342 			}
2343 			if (rounddown2(pa ^ (pa + ptoa(npages) - 1),
2344 			    boundary) != 0) {
2345 				m_inc = atop(roundup2(pa, boundary) - pa);
2346 				continue;
2347 			}
2348 		} else
2349 			KASSERT(m_run != NULL, ("m_run == NULL"));
2350 
2351 		vm_page_change_lock(m, &m_mtx);
2352 		m_inc = 1;
2353 retry:
2354 		if (vm_page_wired(m))
2355 			run_ext = 0;
2356 #if VM_NRESERVLEVEL > 0
2357 		else if ((level = vm_reserv_level(m)) >= 0 &&
2358 		    (options & VPSC_NORESERV) != 0) {
2359 			run_ext = 0;
2360 			/* Advance to the end of the reservation. */
2361 			pa = VM_PAGE_TO_PHYS(m);
2362 			m_inc = atop(roundup2(pa + 1, vm_reserv_size(level)) -
2363 			    pa);
2364 		}
2365 #endif
2366 		else if ((object = m->object) != NULL) {
2367 			/*
2368 			 * The page is considered eligible for relocation if
2369 			 * and only if it could be laundered or reclaimed by
2370 			 * the page daemon.
2371 			 */
2372 			if (!VM_OBJECT_TRYRLOCK(object)) {
2373 				mtx_unlock(m_mtx);
2374 				VM_OBJECT_RLOCK(object);
2375 				mtx_lock(m_mtx);
2376 				if (m->object != object) {
2377 					/*
2378 					 * The page may have been freed.
2379 					 */
2380 					VM_OBJECT_RUNLOCK(object);
2381 					goto retry;
2382 				}
2383 			}
2384 			/* Don't care: PG_NODUMP, PG_ZERO. */
2385 			if (object->type != OBJT_DEFAULT &&
2386 			    object->type != OBJT_SWAP &&
2387 			    object->type != OBJT_VNODE) {
2388 				run_ext = 0;
2389 #if VM_NRESERVLEVEL > 0
2390 			} else if ((options & VPSC_NOSUPER) != 0 &&
2391 			    (level = vm_reserv_level_iffullpop(m)) >= 0) {
2392 				run_ext = 0;
2393 				/* Advance to the end of the superpage. */
2394 				pa = VM_PAGE_TO_PHYS(m);
2395 				m_inc = atop(roundup2(pa + 1,
2396 				    vm_reserv_size(level)) - pa);
2397 #endif
2398 			} else if (object->memattr == VM_MEMATTR_DEFAULT &&
2399 			    vm_page_queue(m) != PQ_NONE && !vm_page_busied(m) &&
2400 			    !vm_page_wired(m)) {
2401 				/*
2402 				 * The page is allocated but eligible for
2403 				 * relocation.  Extend the current run by one
2404 				 * page.
2405 				 */
2406 				KASSERT(pmap_page_get_memattr(m) ==
2407 				    VM_MEMATTR_DEFAULT,
2408 				    ("page %p has an unexpected memattr", m));
2409 				KASSERT((m->oflags & (VPO_SWAPINPROG |
2410 				    VPO_SWAPSLEEP | VPO_UNMANAGED)) == 0,
2411 				    ("page %p has unexpected oflags", m));
2412 				/* Don't care: VPO_NOSYNC. */
2413 				run_ext = 1;
2414 			} else
2415 				run_ext = 0;
2416 			VM_OBJECT_RUNLOCK(object);
2417 #if VM_NRESERVLEVEL > 0
2418 		} else if (level >= 0) {
2419 			/*
2420 			 * The page is reserved but not yet allocated.  In
2421 			 * other words, it is still free.  Extend the current
2422 			 * run by one page.
2423 			 */
2424 			run_ext = 1;
2425 #endif
2426 		} else if ((order = m->order) < VM_NFREEORDER) {
2427 			/*
2428 			 * The page is enqueued in the physical memory
2429 			 * allocator's free page queues.  Moreover, it is the
2430 			 * first page in a power-of-two-sized run of
2431 			 * contiguous free pages.  Add these pages to the end
2432 			 * of the current run, and jump ahead.
2433 			 */
2434 			run_ext = 1 << order;
2435 			m_inc = 1 << order;
2436 		} else {
2437 			/*
2438 			 * Skip the page for one of the following reasons: (1)
2439 			 * It is enqueued in the physical memory allocator's
2440 			 * free page queues.  However, it is not the first
2441 			 * page in a run of contiguous free pages.  (This case
2442 			 * rarely occurs because the scan is performed in
2443 			 * ascending order.) (2) It is not reserved, and it is
2444 			 * transitioning from free to allocated.  (Conversely,
2445 			 * the transition from allocated to free for managed
2446 			 * pages is blocked by the page lock.) (3) It is
2447 			 * allocated but not contained by an object and not
2448 			 * wired, e.g., allocated by Xen's balloon driver.
2449 			 */
2450 			run_ext = 0;
2451 		}
2452 
2453 		/*
2454 		 * Extend or reset the current run of pages.
2455 		 */
2456 		if (run_ext > 0) {
2457 			if (run_len == 0)
2458 				m_run = m;
2459 			run_len += run_ext;
2460 		} else {
2461 			if (run_len > 0) {
2462 				m_run = NULL;
2463 				run_len = 0;
2464 			}
2465 		}
2466 	}
2467 	if (m_mtx != NULL)
2468 		mtx_unlock(m_mtx);
2469 	if (run_len >= npages)
2470 		return (m_run);
2471 	return (NULL);
2472 }
2473 
2474 /*
2475  *	vm_page_reclaim_run:
2476  *
2477  *	Try to relocate each of the allocated virtual pages within the
2478  *	specified run of physical pages to a new physical address.  Free the
2479  *	physical pages underlying the relocated virtual pages.  A virtual page
2480  *	is relocatable if and only if it could be laundered or reclaimed by
2481  *	the page daemon.  Whenever possible, a virtual page is relocated to a
2482  *	physical address above "high".
2483  *
2484  *	Returns 0 if every physical page within the run was already free or
2485  *	just freed by a successful relocation.  Otherwise, returns a non-zero
2486  *	value indicating why the last attempt to relocate a virtual page was
2487  *	unsuccessful.
2488  *
2489  *	"req_class" must be an allocation class.
2490  */
2491 static int
2492 vm_page_reclaim_run(int req_class, int domain, u_long npages, vm_page_t m_run,
2493     vm_paddr_t high)
2494 {
2495 	struct vm_domain *vmd;
2496 	struct mtx *m_mtx;
2497 	struct spglist free;
2498 	vm_object_t object;
2499 	vm_paddr_t pa;
2500 	vm_page_t m, m_end, m_new;
2501 	int error, order, req;
2502 
2503 	KASSERT((req_class & VM_ALLOC_CLASS_MASK) == req_class,
2504 	    ("req_class is not an allocation class"));
2505 	SLIST_INIT(&free);
2506 	error = 0;
2507 	m = m_run;
2508 	m_end = m_run + npages;
2509 	m_mtx = NULL;
2510 	for (; error == 0 && m < m_end; m++) {
2511 		KASSERT((m->flags & (PG_FICTITIOUS | PG_MARKER)) == 0,
2512 		    ("page %p is PG_FICTITIOUS or PG_MARKER", m));
2513 
2514 		/*
2515 		 * Avoid releasing and reacquiring the same page lock.
2516 		 */
2517 		vm_page_change_lock(m, &m_mtx);
2518 retry:
2519 		/*
2520 		 * Racily check for wirings.  Races are handled below.
2521 		 */
2522 		if (vm_page_wired(m))
2523 			error = EBUSY;
2524 		else if ((object = m->object) != NULL) {
2525 			/*
2526 			 * The page is relocated if and only if it could be
2527 			 * laundered or reclaimed by the page daemon.
2528 			 */
2529 			if (!VM_OBJECT_TRYWLOCK(object)) {
2530 				mtx_unlock(m_mtx);
2531 				VM_OBJECT_WLOCK(object);
2532 				mtx_lock(m_mtx);
2533 				if (m->object != object) {
2534 					/*
2535 					 * The page may have been freed.
2536 					 */
2537 					VM_OBJECT_WUNLOCK(object);
2538 					goto retry;
2539 				}
2540 			}
2541 			/* Don't care: PG_NODUMP, PG_ZERO. */
2542 			if (object->type != OBJT_DEFAULT &&
2543 			    object->type != OBJT_SWAP &&
2544 			    object->type != OBJT_VNODE)
2545 				error = EINVAL;
2546 			else if (object->memattr != VM_MEMATTR_DEFAULT)
2547 				error = EINVAL;
2548 			else if (vm_page_queue(m) != PQ_NONE &&
2549 			    !vm_page_busied(m) && !vm_page_wired(m)) {
2550 				KASSERT(pmap_page_get_memattr(m) ==
2551 				    VM_MEMATTR_DEFAULT,
2552 				    ("page %p has an unexpected memattr", m));
2553 				KASSERT((m->oflags & (VPO_SWAPINPROG |
2554 				    VPO_SWAPSLEEP | VPO_UNMANAGED)) == 0,
2555 				    ("page %p has unexpected oflags", m));
2556 				/* Don't care: VPO_NOSYNC. */
2557 				if (m->valid != 0) {
2558 					/*
2559 					 * First, try to allocate a new page
2560 					 * that is above "high".  Failing
2561 					 * that, try to allocate a new page
2562 					 * that is below "m_run".  Allocate
2563 					 * the new page between the end of
2564 					 * "m_run" and "high" only as a last
2565 					 * resort.
2566 					 */
2567 					req = req_class | VM_ALLOC_NOOBJ;
2568 					if ((m->flags & PG_NODUMP) != 0)
2569 						req |= VM_ALLOC_NODUMP;
2570 					if (trunc_page(high) !=
2571 					    ~(vm_paddr_t)PAGE_MASK) {
2572 						m_new = vm_page_alloc_contig(
2573 						    NULL, 0, req, 1,
2574 						    round_page(high),
2575 						    ~(vm_paddr_t)0,
2576 						    PAGE_SIZE, 0,
2577 						    VM_MEMATTR_DEFAULT);
2578 					} else
2579 						m_new = NULL;
2580 					if (m_new == NULL) {
2581 						pa = VM_PAGE_TO_PHYS(m_run);
2582 						m_new = vm_page_alloc_contig(
2583 						    NULL, 0, req, 1,
2584 						    0, pa - 1, PAGE_SIZE, 0,
2585 						    VM_MEMATTR_DEFAULT);
2586 					}
2587 					if (m_new == NULL) {
2588 						pa += ptoa(npages);
2589 						m_new = vm_page_alloc_contig(
2590 						    NULL, 0, req, 1,
2591 						    pa, high, PAGE_SIZE, 0,
2592 						    VM_MEMATTR_DEFAULT);
2593 					}
2594 					if (m_new == NULL) {
2595 						error = ENOMEM;
2596 						goto unlock;
2597 					}
2598 
2599 					/*
2600 					 * Unmap the page and check for new
2601 					 * wirings that may have been acquired
2602 					 * through a pmap lookup.
2603 					 */
2604 					if (object->ref_count != 0 &&
2605 					    !vm_page_try_remove_all(m)) {
2606 						vm_page_free(m_new);
2607 						error = EBUSY;
2608 						goto unlock;
2609 					}
2610 
2611 					/*
2612 					 * Replace "m" with the new page.  For
2613 					 * vm_page_replace(), "m" must be busy
2614 					 * and dequeued.  Finally, change "m"
2615 					 * as if vm_page_free() was called.
2616 					 */
2617 					m_new->aflags = m->aflags &
2618 					    ~PGA_QUEUE_STATE_MASK;
2619 					KASSERT(m_new->oflags == VPO_UNMANAGED,
2620 					    ("page %p is managed", m_new));
2621 					m_new->oflags = m->oflags & VPO_NOSYNC;
2622 					pmap_copy_page(m, m_new);
2623 					m_new->valid = m->valid;
2624 					m_new->dirty = m->dirty;
2625 					m->flags &= ~PG_ZERO;
2626 					vm_page_xbusy(m);
2627 					vm_page_dequeue(m);
2628 					vm_page_replace_checked(m_new, object,
2629 					    m->pindex, m);
2630 					if (vm_page_free_prep(m))
2631 						SLIST_INSERT_HEAD(&free, m,
2632 						    plinks.s.ss);
2633 
2634 					/*
2635 					 * The new page must be deactivated
2636 					 * before the object is unlocked.
2637 					 */
2638 					vm_page_change_lock(m_new, &m_mtx);
2639 					vm_page_deactivate(m_new);
2640 				} else {
2641 					m->flags &= ~PG_ZERO;
2642 					vm_page_dequeue(m);
2643 					if (vm_page_free_prep(m))
2644 						SLIST_INSERT_HEAD(&free, m,
2645 						    plinks.s.ss);
2646 					KASSERT(m->dirty == 0,
2647 					    ("page %p is dirty", m));
2648 				}
2649 			} else
2650 				error = EBUSY;
2651 unlock:
2652 			VM_OBJECT_WUNLOCK(object);
2653 		} else {
2654 			MPASS(vm_phys_domain(m) == domain);
2655 			vmd = VM_DOMAIN(domain);
2656 			vm_domain_free_lock(vmd);
2657 			order = m->order;
2658 			if (order < VM_NFREEORDER) {
2659 				/*
2660 				 * The page is enqueued in the physical memory
2661 				 * allocator's free page queues.  Moreover, it
2662 				 * is the first page in a power-of-two-sized
2663 				 * run of contiguous free pages.  Jump ahead
2664 				 * to the last page within that run, and
2665 				 * continue from there.
2666 				 */
2667 				m += (1 << order) - 1;
2668 			}
2669 #if VM_NRESERVLEVEL > 0
2670 			else if (vm_reserv_is_page_free(m))
2671 				order = 0;
2672 #endif
2673 			vm_domain_free_unlock(vmd);
2674 			if (order == VM_NFREEORDER)
2675 				error = EINVAL;
2676 		}
2677 	}
2678 	if (m_mtx != NULL)
2679 		mtx_unlock(m_mtx);
2680 	if ((m = SLIST_FIRST(&free)) != NULL) {
2681 		int cnt;
2682 
2683 		vmd = VM_DOMAIN(domain);
2684 		cnt = 0;
2685 		vm_domain_free_lock(vmd);
2686 		do {
2687 			MPASS(vm_phys_domain(m) == domain);
2688 			SLIST_REMOVE_HEAD(&free, plinks.s.ss);
2689 			vm_phys_free_pages(m, 0);
2690 			cnt++;
2691 		} while ((m = SLIST_FIRST(&free)) != NULL);
2692 		vm_domain_free_unlock(vmd);
2693 		vm_domain_freecnt_inc(vmd, cnt);
2694 	}
2695 	return (error);
2696 }
2697 
2698 #define	NRUNS	16
2699 
2700 CTASSERT(powerof2(NRUNS));
2701 
2702 #define	RUN_INDEX(count)	((count) & (NRUNS - 1))
2703 
2704 #define	MIN_RECLAIM	8
2705 
2706 /*
2707  *	vm_page_reclaim_contig:
2708  *
2709  *	Reclaim allocated, contiguous physical memory satisfying the specified
2710  *	conditions by relocating the virtual pages using that physical memory.
2711  *	Returns true if reclamation is successful and false otherwise.  Since
2712  *	relocation requires the allocation of physical pages, reclamation may
2713  *	fail due to a shortage of free pages.  When reclamation fails, callers
2714  *	are expected to perform vm_wait() before retrying a failed allocation
2715  *	operation, e.g., vm_page_alloc_contig().
2716  *
2717  *	The caller must always specify an allocation class through "req".
2718  *
2719  *	allocation classes:
2720  *	VM_ALLOC_NORMAL		normal process request
2721  *	VM_ALLOC_SYSTEM		system *really* needs a page
2722  *	VM_ALLOC_INTERRUPT	interrupt time request
2723  *
2724  *	The optional allocation flags are ignored.
2725  *
2726  *	"npages" must be greater than zero.  Both "alignment" and "boundary"
2727  *	must be a power of two.
2728  */
2729 bool
2730 vm_page_reclaim_contig_domain(int domain, int req, u_long npages,
2731     vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
2732 {
2733 	struct vm_domain *vmd;
2734 	vm_paddr_t curr_low;
2735 	vm_page_t m_run, m_runs[NRUNS];
2736 	u_long count, reclaimed;
2737 	int error, i, options, req_class;
2738 
2739 	KASSERT(npages > 0, ("npages is 0"));
2740 	KASSERT(powerof2(alignment), ("alignment is not a power of 2"));
2741 	KASSERT(powerof2(boundary), ("boundary is not a power of 2"));
2742 	req_class = req & VM_ALLOC_CLASS_MASK;
2743 
2744 	/*
2745 	 * The page daemon is allowed to dig deeper into the free page list.
2746 	 */
2747 	if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT)
2748 		req_class = VM_ALLOC_SYSTEM;
2749 
2750 	/*
2751 	 * Return if the number of free pages cannot satisfy the requested
2752 	 * allocation.
2753 	 */
2754 	vmd = VM_DOMAIN(domain);
2755 	count = vmd->vmd_free_count;
2756 	if (count < npages + vmd->vmd_free_reserved || (count < npages +
2757 	    vmd->vmd_interrupt_free_min && req_class == VM_ALLOC_SYSTEM) ||
2758 	    (count < npages && req_class == VM_ALLOC_INTERRUPT))
2759 		return (false);
2760 
2761 	/*
2762 	 * Scan up to three times, relaxing the restrictions ("options") on
2763 	 * the reclamation of reservations and superpages each time.
2764 	 */
2765 	for (options = VPSC_NORESERV;;) {
2766 		/*
2767 		 * Find the highest runs that satisfy the given constraints
2768 		 * and restrictions, and record them in "m_runs".
2769 		 */
2770 		curr_low = low;
2771 		count = 0;
2772 		for (;;) {
2773 			m_run = vm_phys_scan_contig(domain, npages, curr_low,
2774 			    high, alignment, boundary, options);
2775 			if (m_run == NULL)
2776 				break;
2777 			curr_low = VM_PAGE_TO_PHYS(m_run) + ptoa(npages);
2778 			m_runs[RUN_INDEX(count)] = m_run;
2779 			count++;
2780 		}
2781 
2782 		/*
2783 		 * Reclaim the highest runs in LIFO (descending) order until
2784 		 * the number of reclaimed pages, "reclaimed", is at least
2785 		 * MIN_RECLAIM.  Reset "reclaimed" each time because each
2786 		 * reclamation is idempotent, and runs will (likely) recur
2787 		 * from one scan to the next as restrictions are relaxed.
2788 		 */
2789 		reclaimed = 0;
2790 		for (i = 0; count > 0 && i < NRUNS; i++) {
2791 			count--;
2792 			m_run = m_runs[RUN_INDEX(count)];
2793 			error = vm_page_reclaim_run(req_class, domain, npages,
2794 			    m_run, high);
2795 			if (error == 0) {
2796 				reclaimed += npages;
2797 				if (reclaimed >= MIN_RECLAIM)
2798 					return (true);
2799 			}
2800 		}
2801 
2802 		/*
2803 		 * Either relax the restrictions on the next scan or return if
2804 		 * the last scan had no restrictions.
2805 		 */
2806 		if (options == VPSC_NORESERV)
2807 			options = VPSC_NOSUPER;
2808 		else if (options == VPSC_NOSUPER)
2809 			options = VPSC_ANY;
2810 		else if (options == VPSC_ANY)
2811 			return (reclaimed != 0);
2812 	}
2813 }
2814 
2815 bool
2816 vm_page_reclaim_contig(int req, u_long npages, vm_paddr_t low, vm_paddr_t high,
2817     u_long alignment, vm_paddr_t boundary)
2818 {
2819 	struct vm_domainset_iter di;
2820 	int domain;
2821 	bool ret;
2822 
2823 	vm_domainset_iter_page_init(&di, NULL, 0, &domain, &req);
2824 	do {
2825 		ret = vm_page_reclaim_contig_domain(domain, req, npages, low,
2826 		    high, alignment, boundary);
2827 		if (ret)
2828 			break;
2829 	} while (vm_domainset_iter_page(&di, NULL, &domain) == 0);
2830 
2831 	return (ret);
2832 }
2833 
2834 /*
2835  * Set the domain in the appropriate page level domainset.
2836  */
2837 void
2838 vm_domain_set(struct vm_domain *vmd)
2839 {
2840 
2841 	mtx_lock(&vm_domainset_lock);
2842 	if (!vmd->vmd_minset && vm_paging_min(vmd)) {
2843 		vmd->vmd_minset = 1;
2844 		DOMAINSET_SET(vmd->vmd_domain, &vm_min_domains);
2845 	}
2846 	if (!vmd->vmd_severeset && vm_paging_severe(vmd)) {
2847 		vmd->vmd_severeset = 1;
2848 		DOMAINSET_SET(vmd->vmd_domain, &vm_severe_domains);
2849 	}
2850 	mtx_unlock(&vm_domainset_lock);
2851 }
2852 
2853 /*
2854  * Clear the domain from the appropriate page level domainset.
2855  */
2856 void
2857 vm_domain_clear(struct vm_domain *vmd)
2858 {
2859 
2860 	mtx_lock(&vm_domainset_lock);
2861 	if (vmd->vmd_minset && !vm_paging_min(vmd)) {
2862 		vmd->vmd_minset = 0;
2863 		DOMAINSET_CLR(vmd->vmd_domain, &vm_min_domains);
2864 		if (vm_min_waiters != 0) {
2865 			vm_min_waiters = 0;
2866 			wakeup(&vm_min_domains);
2867 		}
2868 	}
2869 	if (vmd->vmd_severeset && !vm_paging_severe(vmd)) {
2870 		vmd->vmd_severeset = 0;
2871 		DOMAINSET_CLR(vmd->vmd_domain, &vm_severe_domains);
2872 		if (vm_severe_waiters != 0) {
2873 			vm_severe_waiters = 0;
2874 			wakeup(&vm_severe_domains);
2875 		}
2876 	}
2877 
2878 	/*
2879 	 * If pageout daemon needs pages, then tell it that there are
2880 	 * some free.
2881 	 */
2882 	if (vmd->vmd_pageout_pages_needed &&
2883 	    vmd->vmd_free_count >= vmd->vmd_pageout_free_min) {
2884 		wakeup(&vmd->vmd_pageout_pages_needed);
2885 		vmd->vmd_pageout_pages_needed = 0;
2886 	}
2887 
2888 	/* See comments in vm_wait_doms(). */
2889 	if (vm_pageproc_waiters) {
2890 		vm_pageproc_waiters = 0;
2891 		wakeup(&vm_pageproc_waiters);
2892 	}
2893 	mtx_unlock(&vm_domainset_lock);
2894 }
2895 
2896 /*
2897  * Wait for free pages to exceed the min threshold globally.
2898  */
2899 void
2900 vm_wait_min(void)
2901 {
2902 
2903 	mtx_lock(&vm_domainset_lock);
2904 	while (vm_page_count_min()) {
2905 		vm_min_waiters++;
2906 		msleep(&vm_min_domains, &vm_domainset_lock, PVM, "vmwait", 0);
2907 	}
2908 	mtx_unlock(&vm_domainset_lock);
2909 }
2910 
2911 /*
2912  * Wait for free pages to exceed the severe threshold globally.
2913  */
2914 void
2915 vm_wait_severe(void)
2916 {
2917 
2918 	mtx_lock(&vm_domainset_lock);
2919 	while (vm_page_count_severe()) {
2920 		vm_severe_waiters++;
2921 		msleep(&vm_severe_domains, &vm_domainset_lock, PVM,
2922 		    "vmwait", 0);
2923 	}
2924 	mtx_unlock(&vm_domainset_lock);
2925 }
2926 
2927 u_int
2928 vm_wait_count(void)
2929 {
2930 
2931 	return (vm_severe_waiters + vm_min_waiters + vm_pageproc_waiters);
2932 }
2933 
2934 void
2935 vm_wait_doms(const domainset_t *wdoms)
2936 {
2937 
2938 	/*
2939 	 * We use racey wakeup synchronization to avoid expensive global
2940 	 * locking for the pageproc when sleeping with a non-specific vm_wait.
2941 	 * To handle this, we only sleep for one tick in this instance.  It
2942 	 * is expected that most allocations for the pageproc will come from
2943 	 * kmem or vm_page_grab* which will use the more specific and
2944 	 * race-free vm_wait_domain().
2945 	 */
2946 	if (curproc == pageproc) {
2947 		mtx_lock(&vm_domainset_lock);
2948 		vm_pageproc_waiters++;
2949 		msleep(&vm_pageproc_waiters, &vm_domainset_lock, PVM | PDROP,
2950 		    "pageprocwait", 1);
2951 	} else {
2952 		/*
2953 		 * XXX Ideally we would wait only until the allocation could
2954 		 * be satisfied.  This condition can cause new allocators to
2955 		 * consume all freed pages while old allocators wait.
2956 		 */
2957 		mtx_lock(&vm_domainset_lock);
2958 		if (vm_page_count_min_set(wdoms)) {
2959 			vm_min_waiters++;
2960 			msleep(&vm_min_domains, &vm_domainset_lock,
2961 			    PVM | PDROP, "vmwait", 0);
2962 		} else
2963 			mtx_unlock(&vm_domainset_lock);
2964 	}
2965 }
2966 
2967 /*
2968  *	vm_wait_domain:
2969  *
2970  *	Sleep until free pages are available for allocation.
2971  *	- Called in various places after failed memory allocations.
2972  */
2973 void
2974 vm_wait_domain(int domain)
2975 {
2976 	struct vm_domain *vmd;
2977 	domainset_t wdom;
2978 
2979 	vmd = VM_DOMAIN(domain);
2980 	vm_domain_free_assert_unlocked(vmd);
2981 
2982 	if (curproc == pageproc) {
2983 		mtx_lock(&vm_domainset_lock);
2984 		if (vmd->vmd_free_count < vmd->vmd_pageout_free_min) {
2985 			vmd->vmd_pageout_pages_needed = 1;
2986 			msleep(&vmd->vmd_pageout_pages_needed,
2987 			    &vm_domainset_lock, PDROP | PSWP, "VMWait", 0);
2988 		} else
2989 			mtx_unlock(&vm_domainset_lock);
2990 	} else {
2991 		if (pageproc == NULL)
2992 			panic("vm_wait in early boot");
2993 		DOMAINSET_ZERO(&wdom);
2994 		DOMAINSET_SET(vmd->vmd_domain, &wdom);
2995 		vm_wait_doms(&wdom);
2996 	}
2997 }
2998 
2999 /*
3000  *	vm_wait:
3001  *
3002  *	Sleep until free pages are available for allocation in the
3003  *	affinity domains of the obj.  If obj is NULL, the domain set
3004  *	for the calling thread is used.
3005  *	Called in various places after failed memory allocations.
3006  */
3007 void
3008 vm_wait(vm_object_t obj)
3009 {
3010 	struct domainset *d;
3011 
3012 	d = NULL;
3013 
3014 	/*
3015 	 * Carefully fetch pointers only once: the struct domainset
3016 	 * itself is ummutable but the pointer might change.
3017 	 */
3018 	if (obj != NULL)
3019 		d = obj->domain.dr_policy;
3020 	if (d == NULL)
3021 		d = curthread->td_domain.dr_policy;
3022 
3023 	vm_wait_doms(&d->ds_mask);
3024 }
3025 
3026 /*
3027  *	vm_domain_alloc_fail:
3028  *
3029  *	Called when a page allocation function fails.  Informs the
3030  *	pagedaemon and performs the requested wait.  Requires the
3031  *	domain_free and object lock on entry.  Returns with the
3032  *	object lock held and free lock released.  Returns an error when
3033  *	retry is necessary.
3034  *
3035  */
3036 static int
3037 vm_domain_alloc_fail(struct vm_domain *vmd, vm_object_t object, int req)
3038 {
3039 
3040 	vm_domain_free_assert_unlocked(vmd);
3041 
3042 	atomic_add_int(&vmd->vmd_pageout_deficit,
3043 	    max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1));
3044 	if (req & (VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL)) {
3045 		if (object != NULL)
3046 			VM_OBJECT_WUNLOCK(object);
3047 		vm_wait_domain(vmd->vmd_domain);
3048 		if (object != NULL)
3049 			VM_OBJECT_WLOCK(object);
3050 		if (req & VM_ALLOC_WAITOK)
3051 			return (EAGAIN);
3052 	}
3053 
3054 	return (0);
3055 }
3056 
3057 /*
3058  *	vm_waitpfault:
3059  *
3060  *	Sleep until free pages are available for allocation.
3061  *	- Called only in vm_fault so that processes page faulting
3062  *	  can be easily tracked.
3063  *	- Sleeps at a lower priority than vm_wait() so that vm_wait()ing
3064  *	  processes will be able to grab memory first.  Do not change
3065  *	  this balance without careful testing first.
3066  */
3067 void
3068 vm_waitpfault(struct domainset *dset, int timo)
3069 {
3070 
3071 	/*
3072 	 * XXX Ideally we would wait only until the allocation could
3073 	 * be satisfied.  This condition can cause new allocators to
3074 	 * consume all freed pages while old allocators wait.
3075 	 */
3076 	mtx_lock(&vm_domainset_lock);
3077 	if (vm_page_count_min_set(&dset->ds_mask)) {
3078 		vm_min_waiters++;
3079 		msleep(&vm_min_domains, &vm_domainset_lock, PUSER | PDROP,
3080 		    "pfault", timo);
3081 	} else
3082 		mtx_unlock(&vm_domainset_lock);
3083 }
3084 
3085 static struct vm_pagequeue *
3086 vm_page_pagequeue(vm_page_t m)
3087 {
3088 
3089 	uint8_t queue;
3090 
3091 	if ((queue = atomic_load_8(&m->queue)) == PQ_NONE)
3092 		return (NULL);
3093 	return (&vm_pagequeue_domain(m)->vmd_pagequeues[queue]);
3094 }
3095 
3096 static inline void
3097 vm_pqbatch_process_page(struct vm_pagequeue *pq, vm_page_t m)
3098 {
3099 	struct vm_domain *vmd;
3100 	uint8_t qflags;
3101 
3102 	CRITICAL_ASSERT(curthread);
3103 	vm_pagequeue_assert_locked(pq);
3104 
3105 	/*
3106 	 * The page daemon is allowed to set m->queue = PQ_NONE without
3107 	 * the page queue lock held.  In this case it is about to free the page,
3108 	 * which must not have any queue state.
3109 	 */
3110 	qflags = atomic_load_8(&m->aflags);
3111 	KASSERT(pq == vm_page_pagequeue(m) ||
3112 	    (qflags & PGA_QUEUE_STATE_MASK) == 0,
3113 	    ("page %p doesn't belong to queue %p but has aflags %#x",
3114 	    m, pq, qflags));
3115 
3116 	if ((qflags & PGA_DEQUEUE) != 0) {
3117 		if (__predict_true((qflags & PGA_ENQUEUED) != 0))
3118 			vm_pagequeue_remove(pq, m);
3119 		vm_page_dequeue_complete(m);
3120 	} else if ((qflags & (PGA_REQUEUE | PGA_REQUEUE_HEAD)) != 0) {
3121 		if ((qflags & PGA_ENQUEUED) != 0)
3122 			TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
3123 		else {
3124 			vm_pagequeue_cnt_inc(pq);
3125 			vm_page_aflag_set(m, PGA_ENQUEUED);
3126 		}
3127 
3128 		/*
3129 		 * Give PGA_REQUEUE_HEAD precedence over PGA_REQUEUE.
3130 		 * In particular, if both flags are set in close succession,
3131 		 * only PGA_REQUEUE_HEAD will be applied, even if it was set
3132 		 * first.
3133 		 */
3134 		if ((qflags & PGA_REQUEUE_HEAD) != 0) {
3135 			KASSERT(m->queue == PQ_INACTIVE,
3136 			    ("head enqueue not supported for page %p", m));
3137 			vmd = vm_pagequeue_domain(m);
3138 			TAILQ_INSERT_BEFORE(&vmd->vmd_inacthead, m, plinks.q);
3139 		} else
3140 			TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
3141 
3142 		vm_page_aflag_clear(m, qflags & (PGA_REQUEUE |
3143 		    PGA_REQUEUE_HEAD));
3144 	}
3145 }
3146 
3147 static void
3148 vm_pqbatch_process(struct vm_pagequeue *pq, struct vm_batchqueue *bq,
3149     uint8_t queue)
3150 {
3151 	vm_page_t m;
3152 	int i;
3153 
3154 	for (i = 0; i < bq->bq_cnt; i++) {
3155 		m = bq->bq_pa[i];
3156 		if (__predict_false(m->queue != queue))
3157 			continue;
3158 		vm_pqbatch_process_page(pq, m);
3159 	}
3160 	vm_batchqueue_init(bq);
3161 }
3162 
3163 /*
3164  *	vm_page_pqbatch_submit:		[ internal use only ]
3165  *
3166  *	Enqueue a page in the specified page queue's batched work queue.
3167  *	The caller must have encoded the requested operation in the page
3168  *	structure's aflags field.
3169  */
3170 void
3171 vm_page_pqbatch_submit(vm_page_t m, uint8_t queue)
3172 {
3173 	struct vm_batchqueue *bq;
3174 	struct vm_pagequeue *pq;
3175 	int domain;
3176 
3177 	KASSERT((m->oflags & VPO_UNMANAGED) == 0,
3178 	    ("page %p is unmanaged", m));
3179 	KASSERT(mtx_owned(vm_page_lockptr(m)) || m->object == NULL,
3180 	    ("missing synchronization for page %p", m));
3181 	KASSERT(queue < PQ_COUNT, ("invalid queue %d", queue));
3182 
3183 	domain = vm_phys_domain(m);
3184 	pq = &vm_pagequeue_domain(m)->vmd_pagequeues[queue];
3185 
3186 	critical_enter();
3187 	bq = DPCPU_PTR(pqbatch[domain][queue]);
3188 	if (vm_batchqueue_insert(bq, m)) {
3189 		critical_exit();
3190 		return;
3191 	}
3192 	if (!vm_pagequeue_trylock(pq)) {
3193 		critical_exit();
3194 		vm_pagequeue_lock(pq);
3195 		critical_enter();
3196 		bq = DPCPU_PTR(pqbatch[domain][queue]);
3197 	}
3198 	vm_pqbatch_process(pq, bq, queue);
3199 
3200 	/*
3201 	 * The page may have been logically dequeued before we acquired the
3202 	 * page queue lock.  In this case, since we either hold the page lock
3203 	 * or the page is being freed, a different thread cannot be concurrently
3204 	 * enqueuing the page.
3205 	 */
3206 	if (__predict_true(m->queue == queue))
3207 		vm_pqbatch_process_page(pq, m);
3208 	else {
3209 		KASSERT(m->queue == PQ_NONE,
3210 		    ("invalid queue transition for page %p", m));
3211 		KASSERT((m->aflags & PGA_ENQUEUED) == 0,
3212 		    ("page %p is enqueued with invalid queue index", m));
3213 	}
3214 	vm_pagequeue_unlock(pq);
3215 	critical_exit();
3216 }
3217 
3218 /*
3219  *	vm_page_pqbatch_drain:		[ internal use only ]
3220  *
3221  *	Force all per-CPU page queue batch queues to be drained.  This is
3222  *	intended for use in severe memory shortages, to ensure that pages
3223  *	do not remain stuck in the batch queues.
3224  */
3225 void
3226 vm_page_pqbatch_drain(void)
3227 {
3228 	struct thread *td;
3229 	struct vm_domain *vmd;
3230 	struct vm_pagequeue *pq;
3231 	int cpu, domain, queue;
3232 
3233 	td = curthread;
3234 	CPU_FOREACH(cpu) {
3235 		thread_lock(td);
3236 		sched_bind(td, cpu);
3237 		thread_unlock(td);
3238 
3239 		for (domain = 0; domain < vm_ndomains; domain++) {
3240 			vmd = VM_DOMAIN(domain);
3241 			for (queue = 0; queue < PQ_COUNT; queue++) {
3242 				pq = &vmd->vmd_pagequeues[queue];
3243 				vm_pagequeue_lock(pq);
3244 				critical_enter();
3245 				vm_pqbatch_process(pq,
3246 				    DPCPU_PTR(pqbatch[domain][queue]), queue);
3247 				critical_exit();
3248 				vm_pagequeue_unlock(pq);
3249 			}
3250 		}
3251 	}
3252 	thread_lock(td);
3253 	sched_unbind(td);
3254 	thread_unlock(td);
3255 }
3256 
3257 /*
3258  * Complete the logical removal of a page from a page queue.  We must be
3259  * careful to synchronize with the page daemon, which may be concurrently
3260  * examining the page with only the page lock held.  The page must not be
3261  * in a state where it appears to be logically enqueued.
3262  */
3263 static void
3264 vm_page_dequeue_complete(vm_page_t m)
3265 {
3266 
3267 	m->queue = PQ_NONE;
3268 	atomic_thread_fence_rel();
3269 	vm_page_aflag_clear(m, PGA_QUEUE_STATE_MASK);
3270 }
3271 
3272 /*
3273  *	vm_page_dequeue_deferred:	[ internal use only ]
3274  *
3275  *	Request removal of the given page from its current page
3276  *	queue.  Physical removal from the queue may be deferred
3277  *	indefinitely.
3278  *
3279  *	The page must be locked.
3280  */
3281 void
3282 vm_page_dequeue_deferred(vm_page_t m)
3283 {
3284 	uint8_t queue;
3285 
3286 	vm_page_assert_locked(m);
3287 
3288 	if ((queue = vm_page_queue(m)) == PQ_NONE)
3289 		return;
3290 
3291 	/*
3292 	 * Set PGA_DEQUEUE if it is not already set to handle a concurrent call
3293 	 * to vm_page_dequeue_deferred_free().  In particular, avoid modifying
3294 	 * the page's queue state once vm_page_dequeue_deferred_free() has been
3295 	 * called.  In the event of a race, two batch queue entries for the page
3296 	 * will be created, but the second will have no effect.
3297 	 */
3298 	if (vm_page_pqstate_cmpset(m, queue, queue, PGA_DEQUEUE, PGA_DEQUEUE))
3299 		vm_page_pqbatch_submit(m, queue);
3300 }
3301 
3302 /*
3303  * A variant of vm_page_dequeue_deferred() that does not assert the page
3304  * lock and is only to be called from vm_page_free_prep().  Because the
3305  * page is being freed, we can assume that nothing other than the page
3306  * daemon is scheduling queue operations on this page, so we get for
3307  * free the mutual exclusion that is otherwise provided by the page lock.
3308  * To handle races, the page daemon must take care to atomically check
3309  * for PGA_DEQUEUE when updating queue state.
3310  */
3311 static void
3312 vm_page_dequeue_deferred_free(vm_page_t m)
3313 {
3314 	uint8_t queue;
3315 
3316 	KASSERT(m->ref_count == 0, ("page %p has references", m));
3317 
3318 	for (;;) {
3319 		if ((m->aflags & PGA_DEQUEUE) != 0)
3320 			return;
3321 		atomic_thread_fence_acq();
3322 		if ((queue = atomic_load_8(&m->queue)) == PQ_NONE)
3323 			return;
3324 		if (vm_page_pqstate_cmpset(m, queue, queue, PGA_DEQUEUE,
3325 		    PGA_DEQUEUE)) {
3326 			vm_page_pqbatch_submit(m, queue);
3327 			break;
3328 		}
3329 	}
3330 }
3331 
3332 /*
3333  *	vm_page_dequeue:
3334  *
3335  *	Remove the page from whichever page queue it's in, if any.
3336  *	The page must either be locked or unallocated.  This constraint
3337  *	ensures that the queue state of the page will remain consistent
3338  *	after this function returns.
3339  */
3340 void
3341 vm_page_dequeue(vm_page_t m)
3342 {
3343 	struct vm_pagequeue *pq, *pq1;
3344 	uint8_t aflags;
3345 
3346 	KASSERT(mtx_owned(vm_page_lockptr(m)) || m->object == NULL,
3347 	    ("page %p is allocated and unlocked", m));
3348 
3349 	for (pq = vm_page_pagequeue(m);; pq = pq1) {
3350 		if (pq == NULL) {
3351 			/*
3352 			 * A thread may be concurrently executing
3353 			 * vm_page_dequeue_complete().  Ensure that all queue
3354 			 * state is cleared before we return.
3355 			 */
3356 			aflags = atomic_load_8(&m->aflags);
3357 			if ((aflags & PGA_QUEUE_STATE_MASK) == 0)
3358 				return;
3359 			KASSERT((aflags & PGA_DEQUEUE) != 0,
3360 			    ("page %p has unexpected queue state flags %#x",
3361 			    m, aflags));
3362 
3363 			/*
3364 			 * Busy wait until the thread updating queue state is
3365 			 * finished.  Such a thread must be executing in a
3366 			 * critical section.
3367 			 */
3368 			cpu_spinwait();
3369 			pq1 = vm_page_pagequeue(m);
3370 			continue;
3371 		}
3372 		vm_pagequeue_lock(pq);
3373 		if ((pq1 = vm_page_pagequeue(m)) == pq)
3374 			break;
3375 		vm_pagequeue_unlock(pq);
3376 	}
3377 	KASSERT(pq == vm_page_pagequeue(m),
3378 	    ("%s: page %p migrated directly between queues", __func__, m));
3379 	KASSERT((m->aflags & PGA_DEQUEUE) != 0 ||
3380 	    mtx_owned(vm_page_lockptr(m)),
3381 	    ("%s: queued unlocked page %p", __func__, m));
3382 
3383 	if ((m->aflags & PGA_ENQUEUED) != 0)
3384 		vm_pagequeue_remove(pq, m);
3385 	vm_page_dequeue_complete(m);
3386 	vm_pagequeue_unlock(pq);
3387 }
3388 
3389 /*
3390  * Schedule the given page for insertion into the specified page queue.
3391  * Physical insertion of the page may be deferred indefinitely.
3392  */
3393 static void
3394 vm_page_enqueue(vm_page_t m, uint8_t queue)
3395 {
3396 
3397 	vm_page_assert_locked(m);
3398 	KASSERT(m->queue == PQ_NONE && (m->aflags & PGA_QUEUE_STATE_MASK) == 0,
3399 	    ("%s: page %p is already enqueued", __func__, m));
3400 
3401 	m->queue = queue;
3402 	if ((m->aflags & PGA_REQUEUE) == 0)
3403 		vm_page_aflag_set(m, PGA_REQUEUE);
3404 	vm_page_pqbatch_submit(m, queue);
3405 }
3406 
3407 /*
3408  *	vm_page_requeue:		[ internal use only ]
3409  *
3410  *	Schedule a requeue of the given page.
3411  *
3412  *	The page must be locked.
3413  */
3414 void
3415 vm_page_requeue(vm_page_t m)
3416 {
3417 
3418 	vm_page_assert_locked(m);
3419 	KASSERT(vm_page_queue(m) != PQ_NONE,
3420 	    ("%s: page %p is not logically enqueued", __func__, m));
3421 
3422 	if ((m->aflags & PGA_REQUEUE) == 0)
3423 		vm_page_aflag_set(m, PGA_REQUEUE);
3424 	vm_page_pqbatch_submit(m, atomic_load_8(&m->queue));
3425 }
3426 
3427 /*
3428  *	vm_page_swapqueue:		[ internal use only ]
3429  *
3430  *	Move the page from one queue to another, or to the tail of its
3431  *	current queue, in the face of a possible concurrent call to
3432  *	vm_page_dequeue_deferred_free().
3433  */
3434 void
3435 vm_page_swapqueue(vm_page_t m, uint8_t oldq, uint8_t newq)
3436 {
3437 	struct vm_pagequeue *pq;
3438 
3439 	KASSERT(oldq < PQ_COUNT && newq < PQ_COUNT && oldq != newq,
3440 	    ("vm_page_swapqueue: invalid queues (%d, %d)", oldq, newq));
3441 	KASSERT((m->oflags & VPO_UNMANAGED) == 0,
3442 	    ("vm_page_swapqueue: page %p is unmanaged", m));
3443 	vm_page_assert_locked(m);
3444 
3445 	/*
3446 	 * Atomically update the queue field and set PGA_REQUEUE while
3447 	 * ensuring that PGA_DEQUEUE has not been set.
3448 	 */
3449 	pq = &vm_pagequeue_domain(m)->vmd_pagequeues[oldq];
3450 	vm_pagequeue_lock(pq);
3451 	if (!vm_page_pqstate_cmpset(m, oldq, newq, PGA_DEQUEUE, PGA_REQUEUE)) {
3452 		vm_pagequeue_unlock(pq);
3453 		return;
3454 	}
3455 	if ((m->aflags & PGA_ENQUEUED) != 0) {
3456 		vm_pagequeue_remove(pq, m);
3457 		vm_page_aflag_clear(m, PGA_ENQUEUED);
3458 	}
3459 	vm_pagequeue_unlock(pq);
3460 	vm_page_pqbatch_submit(m, newq);
3461 }
3462 
3463 /*
3464  *	vm_page_free_prep:
3465  *
3466  *	Prepares the given page to be put on the free list,
3467  *	disassociating it from any VM object. The caller may return
3468  *	the page to the free list only if this function returns true.
3469  *
3470  *	The object must be locked.  The page must be locked if it is
3471  *	managed.
3472  */
3473 bool
3474 vm_page_free_prep(vm_page_t m)
3475 {
3476 
3477 	/*
3478 	 * Synchronize with threads that have dropped a reference to this
3479 	 * page.
3480 	 */
3481 	atomic_thread_fence_acq();
3482 
3483 #if defined(DIAGNOSTIC) && defined(PHYS_TO_DMAP)
3484 	if (PMAP_HAS_DMAP && (m->flags & PG_ZERO) != 0) {
3485 		uint64_t *p;
3486 		int i;
3487 		p = (uint64_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m));
3488 		for (i = 0; i < PAGE_SIZE / sizeof(uint64_t); i++, p++)
3489 			KASSERT(*p == 0, ("vm_page_free_prep %p PG_ZERO %d %jx",
3490 			    m, i, (uintmax_t)*p));
3491 	}
3492 #endif
3493 	if ((m->oflags & VPO_UNMANAGED) == 0)
3494 		KASSERT(!pmap_page_is_mapped(m),
3495 		    ("vm_page_free_prep: freeing mapped page %p", m));
3496 	else
3497 		KASSERT(m->queue == PQ_NONE,
3498 		    ("vm_page_free_prep: unmanaged page %p is queued", m));
3499 	VM_CNT_INC(v_tfree);
3500 
3501 	if (vm_page_sbusied(m))
3502 		panic("vm_page_free_prep: freeing busy page %p", m);
3503 
3504 	if (m->object != NULL) {
3505 		vm_page_object_remove(m);
3506 
3507 		/*
3508 		 * The object reference can be released without an atomic
3509 		 * operation.
3510 		 */
3511 		KASSERT((m->flags & PG_FICTITIOUS) != 0 ||
3512 		    m->ref_count == VPRC_OBJREF,
3513 		    ("vm_page_free_prep: page %p has unexpected ref_count %u",
3514 		    m, m->ref_count));
3515 		m->object = NULL;
3516 		m->ref_count -= VPRC_OBJREF;
3517 	}
3518 
3519 	/*
3520 	 * If fictitious remove object association and
3521 	 * return.
3522 	 */
3523 	if ((m->flags & PG_FICTITIOUS) != 0) {
3524 		KASSERT(m->ref_count == 1,
3525 		    ("fictitious page %p is referenced", m));
3526 		KASSERT(m->queue == PQ_NONE,
3527 		    ("fictitious page %p is queued", m));
3528 		return (false);
3529 	}
3530 
3531 	/*
3532 	 * Pages need not be dequeued before they are returned to the physical
3533 	 * memory allocator, but they must at least be marked for a deferred
3534 	 * dequeue.
3535 	 */
3536 	if ((m->oflags & VPO_UNMANAGED) == 0)
3537 		vm_page_dequeue_deferred_free(m);
3538 
3539 	m->valid = 0;
3540 	vm_page_undirty(m);
3541 
3542 	if (m->ref_count != 0)
3543 		panic("vm_page_free_prep: page %p has references", m);
3544 
3545 	/*
3546 	 * Restore the default memory attribute to the page.
3547 	 */
3548 	if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT)
3549 		pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT);
3550 
3551 #if VM_NRESERVLEVEL > 0
3552 	/*
3553 	 * Determine whether the page belongs to a reservation.  If the page was
3554 	 * allocated from a per-CPU cache, it cannot belong to a reservation, so
3555 	 * as an optimization, we avoid the check in that case.
3556 	 */
3557 	if ((m->flags & PG_PCPU_CACHE) == 0 && vm_reserv_free_page(m))
3558 		return (false);
3559 #endif
3560 
3561 	return (true);
3562 }
3563 
3564 /*
3565  *	vm_page_free_toq:
3566  *
3567  *	Returns the given page to the free list, disassociating it
3568  *	from any VM object.
3569  *
3570  *	The object must be locked.  The page must be locked if it is
3571  *	managed.
3572  */
3573 void
3574 vm_page_free_toq(vm_page_t m)
3575 {
3576 	struct vm_domain *vmd;
3577 	uma_zone_t zone;
3578 
3579 	if (!vm_page_free_prep(m))
3580 		return;
3581 
3582 	vmd = vm_pagequeue_domain(m);
3583 	zone = vmd->vmd_pgcache[m->pool].zone;
3584 	if ((m->flags & PG_PCPU_CACHE) != 0 && zone != NULL) {
3585 		uma_zfree(zone, m);
3586 		return;
3587 	}
3588 	vm_domain_free_lock(vmd);
3589 	vm_phys_free_pages(m, 0);
3590 	vm_domain_free_unlock(vmd);
3591 	vm_domain_freecnt_inc(vmd, 1);
3592 }
3593 
3594 /*
3595  *	vm_page_free_pages_toq:
3596  *
3597  *	Returns a list of pages to the free list, disassociating it
3598  *	from any VM object.  In other words, this is equivalent to
3599  *	calling vm_page_free_toq() for each page of a list of VM objects.
3600  *
3601  *	The objects must be locked.  The pages must be locked if it is
3602  *	managed.
3603  */
3604 void
3605 vm_page_free_pages_toq(struct spglist *free, bool update_wire_count)
3606 {
3607 	vm_page_t m;
3608 	int count;
3609 
3610 	if (SLIST_EMPTY(free))
3611 		return;
3612 
3613 	count = 0;
3614 	while ((m = SLIST_FIRST(free)) != NULL) {
3615 		count++;
3616 		SLIST_REMOVE_HEAD(free, plinks.s.ss);
3617 		vm_page_free_toq(m);
3618 	}
3619 
3620 	if (update_wire_count)
3621 		vm_wire_sub(count);
3622 }
3623 
3624 /*
3625  * Mark this page as wired down, preventing reclamation by the page daemon
3626  * or when the containing object is destroyed.
3627  */
3628 void
3629 vm_page_wire(vm_page_t m)
3630 {
3631 	u_int old;
3632 
3633 	KASSERT(m->object != NULL,
3634 	    ("vm_page_wire: page %p does not belong to an object", m));
3635 	if (!vm_page_busied(m))
3636 		VM_OBJECT_ASSERT_LOCKED(m->object);
3637 	KASSERT((m->flags & PG_FICTITIOUS) == 0 ||
3638 	    VPRC_WIRE_COUNT(m->ref_count) >= 1,
3639 	    ("vm_page_wire: fictitious page %p has zero wirings", m));
3640 
3641 	old = atomic_fetchadd_int(&m->ref_count, 1);
3642 	KASSERT(VPRC_WIRE_COUNT(old) != VPRC_WIRE_COUNT_MAX,
3643 	    ("vm_page_wire: counter overflow for page %p", m));
3644 	if (VPRC_WIRE_COUNT(old) == 0)
3645 		vm_wire_add(1);
3646 }
3647 
3648 /*
3649  * Attempt to wire a mapped page following a pmap lookup of that page.
3650  * This may fail if a thread is concurrently tearing down mappings of the page.
3651  */
3652 bool
3653 vm_page_wire_mapped(vm_page_t m)
3654 {
3655 	u_int old;
3656 
3657 	old = m->ref_count;
3658 	do {
3659 		KASSERT(old > 0,
3660 		    ("vm_page_wire_mapped: wiring unreferenced page %p", m));
3661 		if ((old & VPRC_BLOCKED) != 0)
3662 			return (false);
3663 	} while (!atomic_fcmpset_int(&m->ref_count, &old, old + 1));
3664 
3665 	if (VPRC_WIRE_COUNT(old) == 0)
3666 		vm_wire_add(1);
3667 	return (true);
3668 }
3669 
3670 /*
3671  * Release one wiring of the specified page, potentially allowing it to be
3672  * paged out.
3673  *
3674  * Only managed pages belonging to an object can be paged out.  If the number
3675  * of wirings transitions to zero and the page is eligible for page out, then
3676  * the page is added to the specified paging queue.  If the released wiring
3677  * represented the last reference to the page, the page is freed.
3678  *
3679  * A managed page must be locked.
3680  */
3681 void
3682 vm_page_unwire(vm_page_t m, uint8_t queue)
3683 {
3684 	u_int old;
3685 	bool locked;
3686 
3687 	KASSERT(queue < PQ_COUNT,
3688 	    ("vm_page_unwire: invalid queue %u request for page %p", queue, m));
3689 
3690 	if ((m->oflags & VPO_UNMANAGED) != 0) {
3691 		if (vm_page_unwire_noq(m) && m->ref_count == 0)
3692 			vm_page_free(m);
3693 		return;
3694 	}
3695 
3696 	/*
3697 	 * Update LRU state before releasing the wiring reference.
3698 	 * We only need to do this once since we hold the page lock.
3699 	 * Use a release store when updating the reference count to
3700 	 * synchronize with vm_page_free_prep().
3701 	 */
3702 	old = m->ref_count;
3703 	locked = false;
3704 	do {
3705 		KASSERT(VPRC_WIRE_COUNT(old) > 0,
3706 		    ("vm_page_unwire: wire count underflow for page %p", m));
3707 		if (!locked && VPRC_WIRE_COUNT(old) == 1) {
3708 			vm_page_lock(m);
3709 			locked = true;
3710 			if (queue == PQ_ACTIVE && vm_page_queue(m) == PQ_ACTIVE)
3711 				vm_page_reference(m);
3712 			else
3713 				vm_page_mvqueue(m, queue);
3714 		}
3715 	} while (!atomic_fcmpset_rel_int(&m->ref_count, &old, old - 1));
3716 
3717 	/*
3718 	 * Release the lock only after the wiring is released, to ensure that
3719 	 * the page daemon does not encounter and dequeue the page while it is
3720 	 * still wired.
3721 	 */
3722 	if (locked)
3723 		vm_page_unlock(m);
3724 
3725 	if (VPRC_WIRE_COUNT(old) == 1) {
3726 		vm_wire_sub(1);
3727 		if (old == 1)
3728 			vm_page_free(m);
3729 	}
3730 }
3731 
3732 /*
3733  * Unwire a page without (re-)inserting it into a page queue.  It is up
3734  * to the caller to enqueue, requeue, or free the page as appropriate.
3735  * In most cases involving managed pages, vm_page_unwire() should be used
3736  * instead.
3737  */
3738 bool
3739 vm_page_unwire_noq(vm_page_t m)
3740 {
3741 	u_int old;
3742 
3743 	old = vm_page_drop(m, 1);
3744 	KASSERT(VPRC_WIRE_COUNT(old) != 0,
3745 	    ("vm_page_unref: counter underflow for page %p", m));
3746 	KASSERT((m->flags & PG_FICTITIOUS) == 0 || VPRC_WIRE_COUNT(old) > 1,
3747 	    ("vm_page_unref: missing ref on fictitious page %p", m));
3748 
3749 	if (VPRC_WIRE_COUNT(old) > 1)
3750 		return (false);
3751 	vm_wire_sub(1);
3752 	return (true);
3753 }
3754 
3755 /*
3756  * Ensure that the page is in the specified page queue.  If the page is
3757  * active or being moved to the active queue, ensure that its act_count is
3758  * at least ACT_INIT but do not otherwise mess with it.  Otherwise, ensure that
3759  * the page is at the tail of its page queue.
3760  *
3761  * The page may be wired.  The caller should release its wiring reference
3762  * before releasing the page lock, otherwise the page daemon may immediately
3763  * dequeue the page.
3764  *
3765  * A managed page must be locked.
3766  */
3767 static __always_inline void
3768 vm_page_mvqueue(vm_page_t m, const uint8_t nqueue)
3769 {
3770 
3771 	vm_page_assert_locked(m);
3772 	KASSERT((m->oflags & VPO_UNMANAGED) == 0,
3773 	    ("vm_page_mvqueue: page %p is unmanaged", m));
3774 
3775 	if (vm_page_queue(m) != nqueue) {
3776 		vm_page_dequeue(m);
3777 		vm_page_enqueue(m, nqueue);
3778 	} else if (nqueue != PQ_ACTIVE) {
3779 		vm_page_requeue(m);
3780 	}
3781 
3782 	if (nqueue == PQ_ACTIVE && m->act_count < ACT_INIT)
3783 		m->act_count = ACT_INIT;
3784 }
3785 
3786 /*
3787  * Put the specified page on the active list (if appropriate).
3788  */
3789 void
3790 vm_page_activate(vm_page_t m)
3791 {
3792 
3793 	if ((m->oflags & VPO_UNMANAGED) != 0 || vm_page_wired(m))
3794 		return;
3795 	vm_page_mvqueue(m, PQ_ACTIVE);
3796 }
3797 
3798 /*
3799  * Move the specified page to the tail of the inactive queue, or requeue
3800  * the page if it is already in the inactive queue.
3801  */
3802 void
3803 vm_page_deactivate(vm_page_t m)
3804 {
3805 
3806 	if ((m->oflags & VPO_UNMANAGED) != 0 || vm_page_wired(m))
3807 		return;
3808 	vm_page_mvqueue(m, PQ_INACTIVE);
3809 }
3810 
3811 /*
3812  * Move the specified page close to the head of the inactive queue,
3813  * bypassing LRU.  A marker page is used to maintain FIFO ordering.
3814  * As with regular enqueues, we use a per-CPU batch queue to reduce
3815  * contention on the page queue lock.
3816  */
3817 static void
3818 _vm_page_deactivate_noreuse(vm_page_t m)
3819 {
3820 
3821 	vm_page_assert_locked(m);
3822 
3823 	if (!vm_page_inactive(m)) {
3824 		vm_page_dequeue(m);
3825 		m->queue = PQ_INACTIVE;
3826 	}
3827 	if ((m->aflags & PGA_REQUEUE_HEAD) == 0)
3828 		vm_page_aflag_set(m, PGA_REQUEUE_HEAD);
3829 	vm_page_pqbatch_submit(m, PQ_INACTIVE);
3830 }
3831 
3832 void
3833 vm_page_deactivate_noreuse(vm_page_t m)
3834 {
3835 
3836 	KASSERT(m->object != NULL,
3837 	    ("vm_page_deactivate_noreuse: page %p has no object", m));
3838 
3839 	if ((m->oflags & VPO_UNMANAGED) == 0 && !vm_page_wired(m))
3840 		_vm_page_deactivate_noreuse(m);
3841 }
3842 
3843 /*
3844  * Put a page in the laundry, or requeue it if it is already there.
3845  */
3846 void
3847 vm_page_launder(vm_page_t m)
3848 {
3849 
3850 	if ((m->oflags & VPO_UNMANAGED) != 0 || vm_page_wired(m))
3851 		return;
3852 	vm_page_mvqueue(m, PQ_LAUNDRY);
3853 }
3854 
3855 /*
3856  * Put a page in the PQ_UNSWAPPABLE holding queue.
3857  */
3858 void
3859 vm_page_unswappable(vm_page_t m)
3860 {
3861 
3862 	vm_page_assert_locked(m);
3863 	KASSERT(!vm_page_wired(m) && (m->oflags & VPO_UNMANAGED) == 0,
3864 	    ("page %p already unswappable", m));
3865 
3866 	vm_page_dequeue(m);
3867 	vm_page_enqueue(m, PQ_UNSWAPPABLE);
3868 }
3869 
3870 static void
3871 vm_page_release_toq(vm_page_t m, int flags)
3872 {
3873 
3874 	vm_page_assert_locked(m);
3875 
3876 	/*
3877 	 * Use a check of the valid bits to determine whether we should
3878 	 * accelerate reclamation of the page.  The object lock might not be
3879 	 * held here, in which case the check is racy.  At worst we will either
3880 	 * accelerate reclamation of a valid page and violate LRU, or
3881 	 * unnecessarily defer reclamation of an invalid page.
3882 	 *
3883 	 * If we were asked to not cache the page, place it near the head of the
3884 	 * inactive queue so that is reclaimed sooner.
3885 	 */
3886 	if ((flags & (VPR_TRYFREE | VPR_NOREUSE)) != 0 || m->valid == 0)
3887 		_vm_page_deactivate_noreuse(m);
3888 	else if (vm_page_active(m))
3889 		vm_page_reference(m);
3890 	else
3891 		vm_page_mvqueue(m, PQ_INACTIVE);
3892 }
3893 
3894 /*
3895  * Unwire a page and either attempt to free it or re-add it to the page queues.
3896  */
3897 void
3898 vm_page_release(vm_page_t m, int flags)
3899 {
3900 	vm_object_t object;
3901 	u_int old;
3902 	bool locked;
3903 
3904 	KASSERT((m->oflags & VPO_UNMANAGED) == 0,
3905 	    ("vm_page_release: page %p is unmanaged", m));
3906 
3907 	if ((flags & VPR_TRYFREE) != 0) {
3908 		for (;;) {
3909 			object = (vm_object_t)atomic_load_ptr(&m->object);
3910 			if (object == NULL)
3911 				break;
3912 			/* Depends on type-stability. */
3913 			if (vm_page_busied(m) || !VM_OBJECT_TRYWLOCK(object)) {
3914 				object = NULL;
3915 				break;
3916 			}
3917 			if (object == m->object)
3918 				break;
3919 			VM_OBJECT_WUNLOCK(object);
3920 		}
3921 		if (__predict_true(object != NULL)) {
3922 			vm_page_release_locked(m, flags);
3923 			VM_OBJECT_WUNLOCK(object);
3924 			return;
3925 		}
3926 	}
3927 
3928 	/*
3929 	 * Update LRU state before releasing the wiring reference.
3930 	 * Use a release store when updating the reference count to
3931 	 * synchronize with vm_page_free_prep().
3932 	 */
3933 	old = m->ref_count;
3934 	locked = false;
3935 	do {
3936 		KASSERT(VPRC_WIRE_COUNT(old) > 0,
3937 		    ("vm_page_unwire: wire count underflow for page %p", m));
3938 		if (!locked && VPRC_WIRE_COUNT(old) == 1) {
3939 			vm_page_lock(m);
3940 			locked = true;
3941 			vm_page_release_toq(m, flags);
3942 		}
3943 	} while (!atomic_fcmpset_rel_int(&m->ref_count, &old, old - 1));
3944 
3945 	/*
3946 	 * Release the lock only after the wiring is released, to ensure that
3947 	 * the page daemon does not encounter and dequeue the page while it is
3948 	 * still wired.
3949 	 */
3950 	if (locked)
3951 		vm_page_unlock(m);
3952 
3953 	if (VPRC_WIRE_COUNT(old) == 1) {
3954 		vm_wire_sub(1);
3955 		if (old == 1)
3956 			vm_page_free(m);
3957 	}
3958 }
3959 
3960 /* See vm_page_release(). */
3961 void
3962 vm_page_release_locked(vm_page_t m, int flags)
3963 {
3964 
3965 	VM_OBJECT_ASSERT_WLOCKED(m->object);
3966 	KASSERT((m->oflags & VPO_UNMANAGED) == 0,
3967 	    ("vm_page_release_locked: page %p is unmanaged", m));
3968 
3969 	if (vm_page_unwire_noq(m)) {
3970 		if ((flags & VPR_TRYFREE) != 0 &&
3971 		    (m->object->ref_count == 0 || !pmap_page_is_mapped(m)) &&
3972 		    m->dirty == 0 && !vm_page_busied(m)) {
3973 			vm_page_free(m);
3974 		} else {
3975 			vm_page_lock(m);
3976 			vm_page_release_toq(m, flags);
3977 			vm_page_unlock(m);
3978 		}
3979 	}
3980 }
3981 
3982 static bool
3983 vm_page_try_blocked_op(vm_page_t m, void (*op)(vm_page_t))
3984 {
3985 	u_int old;
3986 
3987 	KASSERT(m->object != NULL && (m->oflags & VPO_UNMANAGED) == 0,
3988 	    ("vm_page_try_blocked_op: page %p has no object", m));
3989 	KASSERT(!vm_page_busied(m),
3990 	    ("vm_page_try_blocked_op: page %p is busy", m));
3991 	VM_OBJECT_ASSERT_LOCKED(m->object);
3992 
3993 	old = m->ref_count;
3994 	do {
3995 		KASSERT(old != 0,
3996 		    ("vm_page_try_blocked_op: page %p has no references", m));
3997 		if (VPRC_WIRE_COUNT(old) != 0)
3998 			return (false);
3999 	} while (!atomic_fcmpset_int(&m->ref_count, &old, old | VPRC_BLOCKED));
4000 
4001 	(op)(m);
4002 
4003 	/*
4004 	 * If the object is read-locked, new wirings may be created via an
4005 	 * object lookup.
4006 	 */
4007 	old = vm_page_drop(m, VPRC_BLOCKED);
4008 	KASSERT(!VM_OBJECT_WOWNED(m->object) ||
4009 	    old == (VPRC_BLOCKED | VPRC_OBJREF),
4010 	    ("vm_page_try_blocked_op: unexpected refcount value %u for %p",
4011 	    old, m));
4012 	return (true);
4013 }
4014 
4015 /*
4016  * Atomically check for wirings and remove all mappings of the page.
4017  */
4018 bool
4019 vm_page_try_remove_all(vm_page_t m)
4020 {
4021 
4022 	return (vm_page_try_blocked_op(m, pmap_remove_all));
4023 }
4024 
4025 /*
4026  * Atomically check for wirings and remove all writeable mappings of the page.
4027  */
4028 bool
4029 vm_page_try_remove_write(vm_page_t m)
4030 {
4031 
4032 	return (vm_page_try_blocked_op(m, pmap_remove_write));
4033 }
4034 
4035 /*
4036  * vm_page_advise
4037  *
4038  * 	Apply the specified advice to the given page.
4039  *
4040  *	The object and page must be locked.
4041  */
4042 void
4043 vm_page_advise(vm_page_t m, int advice)
4044 {
4045 
4046 	vm_page_assert_locked(m);
4047 	VM_OBJECT_ASSERT_WLOCKED(m->object);
4048 	if (advice == MADV_FREE)
4049 		/*
4050 		 * Mark the page clean.  This will allow the page to be freed
4051 		 * without first paging it out.  MADV_FREE pages are often
4052 		 * quickly reused by malloc(3), so we do not do anything that
4053 		 * would result in a page fault on a later access.
4054 		 */
4055 		vm_page_undirty(m);
4056 	else if (advice != MADV_DONTNEED) {
4057 		if (advice == MADV_WILLNEED)
4058 			vm_page_activate(m);
4059 		return;
4060 	}
4061 
4062 	/*
4063 	 * Clear any references to the page.  Otherwise, the page daemon will
4064 	 * immediately reactivate the page.
4065 	 */
4066 	vm_page_aflag_clear(m, PGA_REFERENCED);
4067 
4068 	if (advice != MADV_FREE && m->dirty == 0 && pmap_is_modified(m))
4069 		vm_page_dirty(m);
4070 
4071 	/*
4072 	 * Place clean pages near the head of the inactive queue rather than
4073 	 * the tail, thus defeating the queue's LRU operation and ensuring that
4074 	 * the page will be reused quickly.  Dirty pages not already in the
4075 	 * laundry are moved there.
4076 	 */
4077 	if (m->dirty == 0)
4078 		vm_page_deactivate_noreuse(m);
4079 	else if (!vm_page_in_laundry(m))
4080 		vm_page_launder(m);
4081 }
4082 
4083 /*
4084  * Grab a page, waiting until we are waken up due to the page
4085  * changing state.  We keep on waiting, if the page continues
4086  * to be in the object.  If the page doesn't exist, first allocate it
4087  * and then conditionally zero it.
4088  *
4089  * This routine may sleep.
4090  *
4091  * The object must be locked on entry.  The lock will, however, be released
4092  * and reacquired if the routine sleeps.
4093  */
4094 vm_page_t
4095 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
4096 {
4097 	vm_page_t m;
4098 	int sleep;
4099 	int pflags;
4100 
4101 	VM_OBJECT_ASSERT_WLOCKED(object);
4102 	KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
4103 	    (allocflags & VM_ALLOC_IGN_SBUSY) != 0,
4104 	    ("vm_page_grab: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY mismatch"));
4105 	pflags = allocflags &
4106 	    ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL);
4107 	if ((allocflags & VM_ALLOC_NOWAIT) == 0)
4108 		pflags |= VM_ALLOC_WAITFAIL;
4109 retrylookup:
4110 	if ((m = vm_page_lookup(object, pindex)) != NULL) {
4111 		sleep = (allocflags & VM_ALLOC_IGN_SBUSY) != 0 ?
4112 		    vm_page_xbusied(m) : vm_page_busied(m);
4113 		if (sleep) {
4114 			if ((allocflags & VM_ALLOC_NOWAIT) != 0)
4115 				return (NULL);
4116 			/*
4117 			 * Reference the page before unlocking and
4118 			 * sleeping so that the page daemon is less
4119 			 * likely to reclaim it.
4120 			 */
4121 			if ((allocflags & VM_ALLOC_NOCREAT) == 0)
4122 				vm_page_aflag_set(m, PGA_REFERENCED);
4123 			vm_page_busy_sleep(m, "pgrbwt", (allocflags &
4124 			    VM_ALLOC_IGN_SBUSY) != 0);
4125 			VM_OBJECT_WLOCK(object);
4126 			if ((allocflags & VM_ALLOC_WAITFAIL) != 0)
4127 				return (NULL);
4128 			goto retrylookup;
4129 		} else {
4130 			if ((allocflags & VM_ALLOC_WIRED) != 0)
4131 				vm_page_wire(m);
4132 			if ((allocflags &
4133 			    (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) == 0)
4134 				vm_page_xbusy(m);
4135 			else if ((allocflags & VM_ALLOC_SBUSY) != 0)
4136 				vm_page_sbusy(m);
4137 			return (m);
4138 		}
4139 	}
4140 	if ((allocflags & VM_ALLOC_NOCREAT) != 0)
4141 		return (NULL);
4142 	m = vm_page_alloc(object, pindex, pflags);
4143 	if (m == NULL) {
4144 		if ((allocflags & VM_ALLOC_NOWAIT) != 0)
4145 			return (NULL);
4146 		goto retrylookup;
4147 	}
4148 	if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0)
4149 		pmap_zero_page(m);
4150 	return (m);
4151 }
4152 
4153 /*
4154  * Grab a page and make it valid, paging in if necessary.  Pages missing from
4155  * their pager are zero filled and validated.
4156  */
4157 int
4158 vm_page_grab_valid(vm_page_t *mp, vm_object_t object, vm_pindex_t pindex, int allocflags)
4159 {
4160 	vm_page_t m;
4161 	bool sleep, xbusy;
4162 	int pflags;
4163 	int rv;
4164 
4165 	KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
4166 	    (allocflags & VM_ALLOC_IGN_SBUSY) != 0,
4167 	    ("vm_page_grab_valid: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY mismatch"));
4168 	KASSERT((allocflags &
4169 	    (VM_ALLOC_NOWAIT | VM_ALLOC_WAITFAIL | VM_ALLOC_ZERO)) == 0,
4170 	    ("vm_page_grab_valid: Invalid flags 0x%X", allocflags));
4171 	VM_OBJECT_ASSERT_WLOCKED(object);
4172 	pflags = allocflags & ~(VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY);
4173 	pflags |= VM_ALLOC_WAITFAIL;
4174 
4175 retrylookup:
4176 	xbusy = false;
4177 	if ((m = vm_page_lookup(object, pindex)) != NULL) {
4178 		/*
4179 		 * If the page is fully valid it can only become invalid
4180 		 * with the object lock held.  If it is not valid it can
4181 		 * become valid with the busy lock held.  Therefore, we
4182 		 * may unnecessarily lock the exclusive busy here if we
4183 		 * race with I/O completion not using the object lock.
4184 		 * However, we will not end up with an invalid page and a
4185 		 * shared lock.
4186 		 */
4187 		if (m->valid != VM_PAGE_BITS_ALL ||
4188 		    (allocflags & (VM_ALLOC_IGN_SBUSY | VM_ALLOC_SBUSY)) == 0) {
4189 			sleep = !vm_page_tryxbusy(m);
4190 			xbusy = true;
4191 		} else
4192 			sleep = !vm_page_trysbusy(m);
4193 		if (sleep) {
4194 			/*
4195 			 * Reference the page before unlocking and
4196 			 * sleeping so that the page daemon is less
4197 			 * likely to reclaim it.
4198 			 */
4199 			if ((allocflags & VM_ALLOC_NOCREAT) == 0)
4200 				vm_page_aflag_set(m, PGA_REFERENCED);
4201 			vm_page_busy_sleep(m, "pgrbwt", (allocflags &
4202 			    VM_ALLOC_IGN_SBUSY) != 0);
4203 			VM_OBJECT_WLOCK(object);
4204 			goto retrylookup;
4205 		}
4206 		if ((allocflags & VM_ALLOC_NOCREAT) != 0 &&
4207 		   m->valid != VM_PAGE_BITS_ALL) {
4208 			if (xbusy)
4209 				vm_page_xunbusy(m);
4210 			else
4211 				vm_page_sunbusy(m);
4212 			*mp = NULL;
4213 			return (VM_PAGER_FAIL);
4214 		}
4215 		if ((allocflags & VM_ALLOC_WIRED) != 0)
4216 			vm_page_wire(m);
4217 		if (m->valid == VM_PAGE_BITS_ALL)
4218 			goto out;
4219 	} else if ((allocflags & VM_ALLOC_NOCREAT) != 0) {
4220 		*mp = NULL;
4221 		return (VM_PAGER_FAIL);
4222 	} else if ((m = vm_page_alloc(object, pindex, pflags)) != NULL) {
4223 		xbusy = true;
4224 	} else {
4225 		goto retrylookup;
4226 	}
4227 
4228 	vm_page_assert_xbusied(m);
4229 	MPASS(xbusy);
4230 	if (vm_pager_has_page(object, pindex, NULL, NULL)) {
4231 		rv = vm_pager_get_pages(object, &m, 1, NULL, NULL);
4232 		if (rv != VM_PAGER_OK) {
4233 			if (allocflags & VM_ALLOC_WIRED)
4234 				vm_page_unwire_noq(m);
4235 			vm_page_free(m);
4236 			*mp = NULL;
4237 			return (rv);
4238 		}
4239 		MPASS(m->valid == VM_PAGE_BITS_ALL);
4240 	} else {
4241 		vm_page_zero_invalid(m, TRUE);
4242 	}
4243 out:
4244 	if ((allocflags & VM_ALLOC_NOBUSY) != 0) {
4245 		if (xbusy)
4246 			vm_page_xunbusy(m);
4247 		else
4248 			vm_page_sunbusy(m);
4249 	}
4250 	if ((allocflags & VM_ALLOC_SBUSY) != 0 && xbusy)
4251 		vm_page_busy_downgrade(m);
4252 	*mp = m;
4253 	return (VM_PAGER_OK);
4254 }
4255 
4256 /*
4257  * Return the specified range of pages from the given object.  For each
4258  * page offset within the range, if a page already exists within the object
4259  * at that offset and it is busy, then wait for it to change state.  If,
4260  * instead, the page doesn't exist, then allocate it.
4261  *
4262  * The caller must always specify an allocation class.
4263  *
4264  * allocation classes:
4265  *	VM_ALLOC_NORMAL		normal process request
4266  *	VM_ALLOC_SYSTEM		system *really* needs the pages
4267  *
4268  * The caller must always specify that the pages are to be busied and/or
4269  * wired.
4270  *
4271  * optional allocation flags:
4272  *	VM_ALLOC_IGN_SBUSY	do not sleep on soft busy pages
4273  *	VM_ALLOC_NOBUSY		do not exclusive busy the page
4274  *	VM_ALLOC_NOWAIT		do not sleep
4275  *	VM_ALLOC_SBUSY		set page to sbusy state
4276  *	VM_ALLOC_WIRED		wire the pages
4277  *	VM_ALLOC_ZERO		zero and validate any invalid pages
4278  *
4279  * If VM_ALLOC_NOWAIT is not specified, this routine may sleep.  Otherwise, it
4280  * may return a partial prefix of the requested range.
4281  */
4282 int
4283 vm_page_grab_pages(vm_object_t object, vm_pindex_t pindex, int allocflags,
4284     vm_page_t *ma, int count)
4285 {
4286 	vm_page_t m, mpred;
4287 	int pflags;
4288 	int i;
4289 	bool sleep;
4290 
4291 	VM_OBJECT_ASSERT_WLOCKED(object);
4292 	KASSERT(((u_int)allocflags >> VM_ALLOC_COUNT_SHIFT) == 0,
4293 	    ("vm_page_grap_pages: VM_ALLOC_COUNT() is not allowed"));
4294 	KASSERT((allocflags & VM_ALLOC_NOBUSY) == 0 ||
4295 	    (allocflags & VM_ALLOC_WIRED) != 0,
4296 	    ("vm_page_grab_pages: the pages must be busied or wired"));
4297 	KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
4298 	    (allocflags & VM_ALLOC_IGN_SBUSY) != 0,
4299 	    ("vm_page_grab_pages: VM_ALLOC_SBUSY/IGN_SBUSY mismatch"));
4300 	if (count == 0)
4301 		return (0);
4302 	pflags = allocflags & ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK |
4303 	    VM_ALLOC_WAITFAIL | VM_ALLOC_IGN_SBUSY);
4304 	if ((allocflags & VM_ALLOC_NOWAIT) == 0)
4305 		pflags |= VM_ALLOC_WAITFAIL;
4306 	i = 0;
4307 retrylookup:
4308 	m = vm_radix_lookup_le(&object->rtree, pindex + i);
4309 	if (m == NULL || m->pindex != pindex + i) {
4310 		mpred = m;
4311 		m = NULL;
4312 	} else
4313 		mpred = TAILQ_PREV(m, pglist, listq);
4314 	for (; i < count; i++) {
4315 		if (m != NULL) {
4316 			sleep = (allocflags & VM_ALLOC_IGN_SBUSY) != 0 ?
4317 			    vm_page_xbusied(m) : vm_page_busied(m);
4318 			if (sleep) {
4319 				if ((allocflags & VM_ALLOC_NOWAIT) != 0)
4320 					break;
4321 				/*
4322 				 * Reference the page before unlocking and
4323 				 * sleeping so that the page daemon is less
4324 				 * likely to reclaim it.
4325 				 */
4326 				if ((allocflags & VM_ALLOC_NOCREAT) == 0)
4327 					vm_page_aflag_set(m, PGA_REFERENCED);
4328 				vm_page_busy_sleep(m, "grbmaw", (allocflags &
4329 				    VM_ALLOC_IGN_SBUSY) != 0);
4330 				VM_OBJECT_WLOCK(object);
4331 				goto retrylookup;
4332 			}
4333 			if ((allocflags & VM_ALLOC_WIRED) != 0)
4334 				vm_page_wire(m);
4335 			if ((allocflags & (VM_ALLOC_NOBUSY |
4336 			    VM_ALLOC_SBUSY)) == 0)
4337 				vm_page_xbusy(m);
4338 			if ((allocflags & VM_ALLOC_SBUSY) != 0)
4339 				vm_page_sbusy(m);
4340 		} else {
4341 			if ((allocflags & VM_ALLOC_NOCREAT) != 0)
4342 				break;
4343 			m = vm_page_alloc_after(object, pindex + i,
4344 			    pflags | VM_ALLOC_COUNT(count - i), mpred);
4345 			if (m == NULL) {
4346 				if ((allocflags & VM_ALLOC_NOWAIT) != 0)
4347 					break;
4348 				goto retrylookup;
4349 			}
4350 		}
4351 		if (m->valid == 0 && (allocflags & VM_ALLOC_ZERO) != 0) {
4352 			if ((m->flags & PG_ZERO) == 0)
4353 				pmap_zero_page(m);
4354 			m->valid = VM_PAGE_BITS_ALL;
4355 		}
4356 		ma[i] = mpred = m;
4357 		m = vm_page_next(m);
4358 	}
4359 	return (i);
4360 }
4361 
4362 /*
4363  * Mapping function for valid or dirty bits in a page.
4364  *
4365  * Inputs are required to range within a page.
4366  */
4367 vm_page_bits_t
4368 vm_page_bits(int base, int size)
4369 {
4370 	int first_bit;
4371 	int last_bit;
4372 
4373 	KASSERT(
4374 	    base + size <= PAGE_SIZE,
4375 	    ("vm_page_bits: illegal base/size %d/%d", base, size)
4376 	);
4377 
4378 	if (size == 0)		/* handle degenerate case */
4379 		return (0);
4380 
4381 	first_bit = base >> DEV_BSHIFT;
4382 	last_bit = (base + size - 1) >> DEV_BSHIFT;
4383 
4384 	return (((vm_page_bits_t)2 << last_bit) -
4385 	    ((vm_page_bits_t)1 << first_bit));
4386 }
4387 
4388 /*
4389  *	vm_page_set_valid_range:
4390  *
4391  *	Sets portions of a page valid.  The arguments are expected
4392  *	to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
4393  *	of any partial chunks touched by the range.  The invalid portion of
4394  *	such chunks will be zeroed.
4395  *
4396  *	(base + size) must be less then or equal to PAGE_SIZE.
4397  */
4398 void
4399 vm_page_set_valid_range(vm_page_t m, int base, int size)
4400 {
4401 	int endoff, frag;
4402 
4403 	VM_OBJECT_ASSERT_WLOCKED(m->object);
4404 	if (size == 0)	/* handle degenerate case */
4405 		return;
4406 
4407 	/*
4408 	 * If the base is not DEV_BSIZE aligned and the valid
4409 	 * bit is clear, we have to zero out a portion of the
4410 	 * first block.
4411 	 */
4412 	if ((frag = rounddown2(base, DEV_BSIZE)) != base &&
4413 	    (m->valid & (1 << (base >> DEV_BSHIFT))) == 0)
4414 		pmap_zero_page_area(m, frag, base - frag);
4415 
4416 	/*
4417 	 * If the ending offset is not DEV_BSIZE aligned and the
4418 	 * valid bit is clear, we have to zero out a portion of
4419 	 * the last block.
4420 	 */
4421 	endoff = base + size;
4422 	if ((frag = rounddown2(endoff, DEV_BSIZE)) != endoff &&
4423 	    (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0)
4424 		pmap_zero_page_area(m, endoff,
4425 		    DEV_BSIZE - (endoff & (DEV_BSIZE - 1)));
4426 
4427 	/*
4428 	 * Assert that no previously invalid block that is now being validated
4429 	 * is already dirty.
4430 	 */
4431 	KASSERT((~m->valid & vm_page_bits(base, size) & m->dirty) == 0,
4432 	    ("vm_page_set_valid_range: page %p is dirty", m));
4433 
4434 	/*
4435 	 * Set valid bits inclusive of any overlap.
4436 	 */
4437 	m->valid |= vm_page_bits(base, size);
4438 }
4439 
4440 /*
4441  * Clear the given bits from the specified page's dirty field.
4442  */
4443 static __inline void
4444 vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits)
4445 {
4446 	uintptr_t addr;
4447 #if PAGE_SIZE < 16384
4448 	int shift;
4449 #endif
4450 
4451 	/*
4452 	 * If the object is locked and the page is neither exclusive busy nor
4453 	 * write mapped, then the page's dirty field cannot possibly be
4454 	 * set by a concurrent pmap operation.
4455 	 */
4456 	VM_OBJECT_ASSERT_WLOCKED(m->object);
4457 	if (!vm_page_xbusied(m) && !pmap_page_is_write_mapped(m))
4458 		m->dirty &= ~pagebits;
4459 	else {
4460 		/*
4461 		 * The pmap layer can call vm_page_dirty() without
4462 		 * holding a distinguished lock.  The combination of
4463 		 * the object's lock and an atomic operation suffice
4464 		 * to guarantee consistency of the page dirty field.
4465 		 *
4466 		 * For PAGE_SIZE == 32768 case, compiler already
4467 		 * properly aligns the dirty field, so no forcible
4468 		 * alignment is needed. Only require existence of
4469 		 * atomic_clear_64 when page size is 32768.
4470 		 */
4471 		addr = (uintptr_t)&m->dirty;
4472 #if PAGE_SIZE == 32768
4473 		atomic_clear_64((uint64_t *)addr, pagebits);
4474 #elif PAGE_SIZE == 16384
4475 		atomic_clear_32((uint32_t *)addr, pagebits);
4476 #else		/* PAGE_SIZE <= 8192 */
4477 		/*
4478 		 * Use a trick to perform a 32-bit atomic on the
4479 		 * containing aligned word, to not depend on the existence
4480 		 * of atomic_clear_{8, 16}.
4481 		 */
4482 		shift = addr & (sizeof(uint32_t) - 1);
4483 #if BYTE_ORDER == BIG_ENDIAN
4484 		shift = (sizeof(uint32_t) - sizeof(m->dirty) - shift) * NBBY;
4485 #else
4486 		shift *= NBBY;
4487 #endif
4488 		addr &= ~(sizeof(uint32_t) - 1);
4489 		atomic_clear_32((uint32_t *)addr, pagebits << shift);
4490 #endif		/* PAGE_SIZE */
4491 	}
4492 }
4493 
4494 /*
4495  *	vm_page_set_validclean:
4496  *
4497  *	Sets portions of a page valid and clean.  The arguments are expected
4498  *	to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
4499  *	of any partial chunks touched by the range.  The invalid portion of
4500  *	such chunks will be zero'd.
4501  *
4502  *	(base + size) must be less then or equal to PAGE_SIZE.
4503  */
4504 void
4505 vm_page_set_validclean(vm_page_t m, int base, int size)
4506 {
4507 	vm_page_bits_t oldvalid, pagebits;
4508 	int endoff, frag;
4509 
4510 	VM_OBJECT_ASSERT_WLOCKED(m->object);
4511 	if (size == 0)	/* handle degenerate case */
4512 		return;
4513 
4514 	/*
4515 	 * If the base is not DEV_BSIZE aligned and the valid
4516 	 * bit is clear, we have to zero out a portion of the
4517 	 * first block.
4518 	 */
4519 	if ((frag = rounddown2(base, DEV_BSIZE)) != base &&
4520 	    (m->valid & ((vm_page_bits_t)1 << (base >> DEV_BSHIFT))) == 0)
4521 		pmap_zero_page_area(m, frag, base - frag);
4522 
4523 	/*
4524 	 * If the ending offset is not DEV_BSIZE aligned and the
4525 	 * valid bit is clear, we have to zero out a portion of
4526 	 * the last block.
4527 	 */
4528 	endoff = base + size;
4529 	if ((frag = rounddown2(endoff, DEV_BSIZE)) != endoff &&
4530 	    (m->valid & ((vm_page_bits_t)1 << (endoff >> DEV_BSHIFT))) == 0)
4531 		pmap_zero_page_area(m, endoff,
4532 		    DEV_BSIZE - (endoff & (DEV_BSIZE - 1)));
4533 
4534 	/*
4535 	 * Set valid, clear dirty bits.  If validating the entire
4536 	 * page we can safely clear the pmap modify bit.  We also
4537 	 * use this opportunity to clear the VPO_NOSYNC flag.  If a process
4538 	 * takes a write fault on a MAP_NOSYNC memory area the flag will
4539 	 * be set again.
4540 	 *
4541 	 * We set valid bits inclusive of any overlap, but we can only
4542 	 * clear dirty bits for DEV_BSIZE chunks that are fully within
4543 	 * the range.
4544 	 */
4545 	oldvalid = m->valid;
4546 	pagebits = vm_page_bits(base, size);
4547 	m->valid |= pagebits;
4548 #if 0	/* NOT YET */
4549 	if ((frag = base & (DEV_BSIZE - 1)) != 0) {
4550 		frag = DEV_BSIZE - frag;
4551 		base += frag;
4552 		size -= frag;
4553 		if (size < 0)
4554 			size = 0;
4555 	}
4556 	pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1));
4557 #endif
4558 	if (base == 0 && size == PAGE_SIZE) {
4559 		/*
4560 		 * The page can only be modified within the pmap if it is
4561 		 * mapped, and it can only be mapped if it was previously
4562 		 * fully valid.
4563 		 */
4564 		if (oldvalid == VM_PAGE_BITS_ALL)
4565 			/*
4566 			 * Perform the pmap_clear_modify() first.  Otherwise,
4567 			 * a concurrent pmap operation, such as
4568 			 * pmap_protect(), could clear a modification in the
4569 			 * pmap and set the dirty field on the page before
4570 			 * pmap_clear_modify() had begun and after the dirty
4571 			 * field was cleared here.
4572 			 */
4573 			pmap_clear_modify(m);
4574 		m->dirty = 0;
4575 		m->oflags &= ~VPO_NOSYNC;
4576 	} else if (oldvalid != VM_PAGE_BITS_ALL)
4577 		m->dirty &= ~pagebits;
4578 	else
4579 		vm_page_clear_dirty_mask(m, pagebits);
4580 }
4581 
4582 void
4583 vm_page_clear_dirty(vm_page_t m, int base, int size)
4584 {
4585 
4586 	vm_page_clear_dirty_mask(m, vm_page_bits(base, size));
4587 }
4588 
4589 /*
4590  *	vm_page_set_invalid:
4591  *
4592  *	Invalidates DEV_BSIZE'd chunks within a page.  Both the
4593  *	valid and dirty bits for the effected areas are cleared.
4594  */
4595 void
4596 vm_page_set_invalid(vm_page_t m, int base, int size)
4597 {
4598 	vm_page_bits_t bits;
4599 	vm_object_t object;
4600 
4601 	object = m->object;
4602 	VM_OBJECT_ASSERT_WLOCKED(object);
4603 	if (object->type == OBJT_VNODE && base == 0 && IDX_TO_OFF(m->pindex) +
4604 	    size >= object->un_pager.vnp.vnp_size)
4605 		bits = VM_PAGE_BITS_ALL;
4606 	else
4607 		bits = vm_page_bits(base, size);
4608 	if (object->ref_count != 0 && m->valid == VM_PAGE_BITS_ALL &&
4609 	    bits != 0)
4610 		pmap_remove_all(m);
4611 	KASSERT((bits == 0 && m->valid == VM_PAGE_BITS_ALL) ||
4612 	    !pmap_page_is_mapped(m),
4613 	    ("vm_page_set_invalid: page %p is mapped", m));
4614 	m->valid &= ~bits;
4615 	m->dirty &= ~bits;
4616 }
4617 
4618 /*
4619  * vm_page_zero_invalid()
4620  *
4621  *	The kernel assumes that the invalid portions of a page contain
4622  *	garbage, but such pages can be mapped into memory by user code.
4623  *	When this occurs, we must zero out the non-valid portions of the
4624  *	page so user code sees what it expects.
4625  *
4626  *	Pages are most often semi-valid when the end of a file is mapped
4627  *	into memory and the file's size is not page aligned.
4628  */
4629 void
4630 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
4631 {
4632 	int b;
4633 	int i;
4634 
4635 	VM_OBJECT_ASSERT_WLOCKED(m->object);
4636 	/*
4637 	 * Scan the valid bits looking for invalid sections that
4638 	 * must be zeroed.  Invalid sub-DEV_BSIZE'd areas ( where the
4639 	 * valid bit may be set ) have already been zeroed by
4640 	 * vm_page_set_validclean().
4641 	 */
4642 	for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
4643 		if (i == (PAGE_SIZE / DEV_BSIZE) ||
4644 		    (m->valid & ((vm_page_bits_t)1 << i))) {
4645 			if (i > b) {
4646 				pmap_zero_page_area(m,
4647 				    b << DEV_BSHIFT, (i - b) << DEV_BSHIFT);
4648 			}
4649 			b = i + 1;
4650 		}
4651 	}
4652 
4653 	/*
4654 	 * setvalid is TRUE when we can safely set the zero'd areas
4655 	 * as being valid.  We can do this if there are no cache consistancy
4656 	 * issues.  e.g. it is ok to do with UFS, but not ok to do with NFS.
4657 	 */
4658 	if (setvalid)
4659 		m->valid = VM_PAGE_BITS_ALL;
4660 }
4661 
4662 /*
4663  *	vm_page_is_valid:
4664  *
4665  *	Is (partial) page valid?  Note that the case where size == 0
4666  *	will return FALSE in the degenerate case where the page is
4667  *	entirely invalid, and TRUE otherwise.
4668  */
4669 int
4670 vm_page_is_valid(vm_page_t m, int base, int size)
4671 {
4672 	vm_page_bits_t bits;
4673 
4674 	VM_OBJECT_ASSERT_LOCKED(m->object);
4675 	bits = vm_page_bits(base, size);
4676 	return (m->valid != 0 && (m->valid & bits) == bits);
4677 }
4678 
4679 /*
4680  * Returns true if all of the specified predicates are true for the entire
4681  * (super)page and false otherwise.
4682  */
4683 bool
4684 vm_page_ps_test(vm_page_t m, int flags, vm_page_t skip_m)
4685 {
4686 	vm_object_t object;
4687 	int i, npages;
4688 
4689 	object = m->object;
4690 	if (skip_m != NULL && skip_m->object != object)
4691 		return (false);
4692 	VM_OBJECT_ASSERT_LOCKED(object);
4693 	npages = atop(pagesizes[m->psind]);
4694 
4695 	/*
4696 	 * The physically contiguous pages that make up a superpage, i.e., a
4697 	 * page with a page size index ("psind") greater than zero, will
4698 	 * occupy adjacent entries in vm_page_array[].
4699 	 */
4700 	for (i = 0; i < npages; i++) {
4701 		/* Always test object consistency, including "skip_m". */
4702 		if (m[i].object != object)
4703 			return (false);
4704 		if (&m[i] == skip_m)
4705 			continue;
4706 		if ((flags & PS_NONE_BUSY) != 0 && vm_page_busied(&m[i]))
4707 			return (false);
4708 		if ((flags & PS_ALL_DIRTY) != 0) {
4709 			/*
4710 			 * Calling vm_page_test_dirty() or pmap_is_modified()
4711 			 * might stop this case from spuriously returning
4712 			 * "false".  However, that would require a write lock
4713 			 * on the object containing "m[i]".
4714 			 */
4715 			if (m[i].dirty != VM_PAGE_BITS_ALL)
4716 				return (false);
4717 		}
4718 		if ((flags & PS_ALL_VALID) != 0 &&
4719 		    m[i].valid != VM_PAGE_BITS_ALL)
4720 			return (false);
4721 	}
4722 	return (true);
4723 }
4724 
4725 /*
4726  * Set the page's dirty bits if the page is modified.
4727  */
4728 void
4729 vm_page_test_dirty(vm_page_t m)
4730 {
4731 
4732 	VM_OBJECT_ASSERT_WLOCKED(m->object);
4733 	if (m->dirty != VM_PAGE_BITS_ALL && pmap_is_modified(m))
4734 		vm_page_dirty(m);
4735 }
4736 
4737 void
4738 vm_page_lock_KBI(vm_page_t m, const char *file, int line)
4739 {
4740 
4741 	mtx_lock_flags_(vm_page_lockptr(m), 0, file, line);
4742 }
4743 
4744 void
4745 vm_page_unlock_KBI(vm_page_t m, const char *file, int line)
4746 {
4747 
4748 	mtx_unlock_flags_(vm_page_lockptr(m), 0, file, line);
4749 }
4750 
4751 int
4752 vm_page_trylock_KBI(vm_page_t m, const char *file, int line)
4753 {
4754 
4755 	return (mtx_trylock_flags_(vm_page_lockptr(m), 0, file, line));
4756 }
4757 
4758 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
4759 void
4760 vm_page_assert_locked_KBI(vm_page_t m, const char *file, int line)
4761 {
4762 
4763 	vm_page_lock_assert_KBI(m, MA_OWNED, file, line);
4764 }
4765 
4766 void
4767 vm_page_lock_assert_KBI(vm_page_t m, int a, const char *file, int line)
4768 {
4769 
4770 	mtx_assert_(vm_page_lockptr(m), a, file, line);
4771 }
4772 #endif
4773 
4774 #ifdef INVARIANTS
4775 void
4776 vm_page_object_lock_assert(vm_page_t m)
4777 {
4778 
4779 	/*
4780 	 * Certain of the page's fields may only be modified by the
4781 	 * holder of the containing object's lock or the exclusive busy.
4782 	 * holder.  Unfortunately, the holder of the write busy is
4783 	 * not recorded, and thus cannot be checked here.
4784 	 */
4785 	if (m->object != NULL && !vm_page_xbusied(m))
4786 		VM_OBJECT_ASSERT_WLOCKED(m->object);
4787 }
4788 
4789 void
4790 vm_page_assert_pga_writeable(vm_page_t m, uint8_t bits)
4791 {
4792 
4793 	if ((bits & PGA_WRITEABLE) == 0)
4794 		return;
4795 
4796 	/*
4797 	 * The PGA_WRITEABLE flag can only be set if the page is
4798 	 * managed, is exclusively busied or the object is locked.
4799 	 * Currently, this flag is only set by pmap_enter().
4800 	 */
4801 	KASSERT((m->oflags & VPO_UNMANAGED) == 0,
4802 	    ("PGA_WRITEABLE on unmanaged page"));
4803 	if (!vm_page_xbusied(m))
4804 		VM_OBJECT_ASSERT_LOCKED(m->object);
4805 }
4806 #endif
4807 
4808 #include "opt_ddb.h"
4809 #ifdef DDB
4810 #include <sys/kernel.h>
4811 
4812 #include <ddb/ddb.h>
4813 
4814 DB_SHOW_COMMAND(page, vm_page_print_page_info)
4815 {
4816 
4817 	db_printf("vm_cnt.v_free_count: %d\n", vm_free_count());
4818 	db_printf("vm_cnt.v_inactive_count: %d\n", vm_inactive_count());
4819 	db_printf("vm_cnt.v_active_count: %d\n", vm_active_count());
4820 	db_printf("vm_cnt.v_laundry_count: %d\n", vm_laundry_count());
4821 	db_printf("vm_cnt.v_wire_count: %d\n", vm_wire_count());
4822 	db_printf("vm_cnt.v_free_reserved: %d\n", vm_cnt.v_free_reserved);
4823 	db_printf("vm_cnt.v_free_min: %d\n", vm_cnt.v_free_min);
4824 	db_printf("vm_cnt.v_free_target: %d\n", vm_cnt.v_free_target);
4825 	db_printf("vm_cnt.v_inactive_target: %d\n", vm_cnt.v_inactive_target);
4826 }
4827 
4828 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
4829 {
4830 	int dom;
4831 
4832 	db_printf("pq_free %d\n", vm_free_count());
4833 	for (dom = 0; dom < vm_ndomains; dom++) {
4834 		db_printf(
4835     "dom %d page_cnt %d free %d pq_act %d pq_inact %d pq_laund %d pq_unsw %d\n",
4836 		    dom,
4837 		    vm_dom[dom].vmd_page_count,
4838 		    vm_dom[dom].vmd_free_count,
4839 		    vm_dom[dom].vmd_pagequeues[PQ_ACTIVE].pq_cnt,
4840 		    vm_dom[dom].vmd_pagequeues[PQ_INACTIVE].pq_cnt,
4841 		    vm_dom[dom].vmd_pagequeues[PQ_LAUNDRY].pq_cnt,
4842 		    vm_dom[dom].vmd_pagequeues[PQ_UNSWAPPABLE].pq_cnt);
4843 	}
4844 }
4845 
4846 DB_SHOW_COMMAND(pginfo, vm_page_print_pginfo)
4847 {
4848 	vm_page_t m;
4849 	boolean_t phys, virt;
4850 
4851 	if (!have_addr) {
4852 		db_printf("show pginfo addr\n");
4853 		return;
4854 	}
4855 
4856 	phys = strchr(modif, 'p') != NULL;
4857 	virt = strchr(modif, 'v') != NULL;
4858 	if (virt)
4859 		m = PHYS_TO_VM_PAGE(pmap_kextract(addr));
4860 	else if (phys)
4861 		m = PHYS_TO_VM_PAGE(addr);
4862 	else
4863 		m = (vm_page_t)addr;
4864 	db_printf(
4865     "page %p obj %p pidx 0x%jx phys 0x%jx q %d ref %u\n"
4866     "  af 0x%x of 0x%x f 0x%x act %d busy %x valid 0x%x dirty 0x%x\n",
4867 	    m, m->object, (uintmax_t)m->pindex, (uintmax_t)m->phys_addr,
4868 	    m->queue, m->ref_count, m->aflags, m->oflags,
4869 	    m->flags, m->act_count, m->busy_lock, m->valid, m->dirty);
4870 }
4871 #endif /* DDB */
4872