xref: /freebsd/sys/vm/vm_page.c (revision 895f86f15fbf6540071feb9328c3c50ed1f027b8)
1 /*-
2  * Copyright (c) 1991 Regents of the University of California.
3  * All rights reserved.
4  * Copyright (c) 1998 Matthew Dillon.  All Rights Reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * The Mach Operating System project at Carnegie-Mellon University.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	from: @(#)vm_page.c	7.4 (Berkeley) 5/7/91
34  */
35 
36 /*-
37  * Copyright (c) 1987, 1990 Carnegie-Mellon University.
38  * All rights reserved.
39  *
40  * Authors: Avadis Tevanian, Jr., Michael Wayne Young
41  *
42  * Permission to use, copy, modify and distribute this software and
43  * its documentation is hereby granted, provided that both the copyright
44  * notice and this permission notice appear in all copies of the
45  * software, derivative works or modified versions, and any portions
46  * thereof, and that both notices appear in supporting documentation.
47  *
48  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
49  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
50  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
51  *
52  * Carnegie Mellon requests users of this software to return to
53  *
54  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
55  *  School of Computer Science
56  *  Carnegie Mellon University
57  *  Pittsburgh PA 15213-3890
58  *
59  * any improvements or extensions that they make and grant Carnegie the
60  * rights to redistribute these changes.
61  */
62 
63 /*
64  *			GENERAL RULES ON VM_PAGE MANIPULATION
65  *
66  *	- A page queue lock is required when adding or removing a page from a
67  *	  page queue regardless of other locks or the busy state of a page.
68  *
69  *		* In general, no thread besides the page daemon can acquire or
70  *		  hold more than one page queue lock at a time.
71  *
72  *		* The page daemon can acquire and hold any pair of page queue
73  *		  locks in any order.
74  *
75  *	- The object lock is required when inserting or removing
76  *	  pages from an object (vm_page_insert() or vm_page_remove()).
77  *
78  */
79 
80 /*
81  *	Resident memory management module.
82  */
83 
84 #include <sys/cdefs.h>
85 __FBSDID("$FreeBSD$");
86 
87 #include "opt_vm.h"
88 
89 #include <sys/param.h>
90 #include <sys/systm.h>
91 #include <sys/lock.h>
92 #include <sys/kernel.h>
93 #include <sys/limits.h>
94 #include <sys/linker.h>
95 #include <sys/malloc.h>
96 #include <sys/mman.h>
97 #include <sys/msgbuf.h>
98 #include <sys/mutex.h>
99 #include <sys/proc.h>
100 #include <sys/rwlock.h>
101 #include <sys/sbuf.h>
102 #include <sys/sysctl.h>
103 #include <sys/vmmeter.h>
104 #include <sys/vnode.h>
105 
106 #include <vm/vm.h>
107 #include <vm/pmap.h>
108 #include <vm/vm_param.h>
109 #include <vm/vm_kern.h>
110 #include <vm/vm_object.h>
111 #include <vm/vm_page.h>
112 #include <vm/vm_pageout.h>
113 #include <vm/vm_pager.h>
114 #include <vm/vm_phys.h>
115 #include <vm/vm_radix.h>
116 #include <vm/vm_reserv.h>
117 #include <vm/vm_extern.h>
118 #include <vm/uma.h>
119 #include <vm/uma_int.h>
120 
121 #include <machine/md_var.h>
122 
123 /*
124  *	Associated with page of user-allocatable memory is a
125  *	page structure.
126  */
127 
128 struct vm_domain vm_dom[MAXMEMDOM];
129 struct mtx_padalign vm_page_queue_free_mtx;
130 
131 struct mtx_padalign pa_lock[PA_LOCK_COUNT];
132 
133 vm_page_t vm_page_array;
134 long vm_page_array_size;
135 long first_page;
136 int vm_page_zero_count;
137 
138 static int boot_pages = UMA_BOOT_PAGES;
139 SYSCTL_INT(_vm, OID_AUTO, boot_pages, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
140     &boot_pages, 0,
141     "number of pages allocated for bootstrapping the VM system");
142 
143 static int pa_tryrelock_restart;
144 SYSCTL_INT(_vm, OID_AUTO, tryrelock_restart, CTLFLAG_RD,
145     &pa_tryrelock_restart, 0, "Number of tryrelock restarts");
146 
147 static TAILQ_HEAD(, vm_page) blacklist_head;
148 static int sysctl_vm_page_blacklist(SYSCTL_HANDLER_ARGS);
149 SYSCTL_PROC(_vm, OID_AUTO, page_blacklist, CTLTYPE_STRING | CTLFLAG_RD |
150     CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_page_blacklist, "A", "Blacklist pages");
151 
152 /* Is the page daemon waiting for free pages? */
153 static int vm_pageout_pages_needed;
154 
155 static uma_zone_t fakepg_zone;
156 
157 static struct vnode *vm_page_alloc_init(vm_page_t m);
158 static void vm_page_cache_turn_free(vm_page_t m);
159 static void vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits);
160 static void vm_page_enqueue(uint8_t queue, vm_page_t m);
161 static void vm_page_init_fakepg(void *dummy);
162 static int vm_page_insert_after(vm_page_t m, vm_object_t object,
163     vm_pindex_t pindex, vm_page_t mpred);
164 static void vm_page_insert_radixdone(vm_page_t m, vm_object_t object,
165     vm_page_t mpred);
166 
167 SYSINIT(vm_page, SI_SUB_VM, SI_ORDER_SECOND, vm_page_init_fakepg, NULL);
168 
169 static void
170 vm_page_init_fakepg(void *dummy)
171 {
172 
173 	fakepg_zone = uma_zcreate("fakepg", sizeof(struct vm_page), NULL, NULL,
174 	    NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE | UMA_ZONE_VM);
175 }
176 
177 /* Make sure that u_long is at least 64 bits when PAGE_SIZE is 32K. */
178 #if PAGE_SIZE == 32768
179 #ifdef CTASSERT
180 CTASSERT(sizeof(u_long) >= 8);
181 #endif
182 #endif
183 
184 /*
185  * Try to acquire a physical address lock while a pmap is locked.  If we
186  * fail to trylock we unlock and lock the pmap directly and cache the
187  * locked pa in *locked.  The caller should then restart their loop in case
188  * the virtual to physical mapping has changed.
189  */
190 int
191 vm_page_pa_tryrelock(pmap_t pmap, vm_paddr_t pa, vm_paddr_t *locked)
192 {
193 	vm_paddr_t lockpa;
194 
195 	lockpa = *locked;
196 	*locked = pa;
197 	if (lockpa) {
198 		PA_LOCK_ASSERT(lockpa, MA_OWNED);
199 		if (PA_LOCKPTR(pa) == PA_LOCKPTR(lockpa))
200 			return (0);
201 		PA_UNLOCK(lockpa);
202 	}
203 	if (PA_TRYLOCK(pa))
204 		return (0);
205 	PMAP_UNLOCK(pmap);
206 	atomic_add_int(&pa_tryrelock_restart, 1);
207 	PA_LOCK(pa);
208 	PMAP_LOCK(pmap);
209 	return (EAGAIN);
210 }
211 
212 /*
213  *	vm_set_page_size:
214  *
215  *	Sets the page size, perhaps based upon the memory
216  *	size.  Must be called before any use of page-size
217  *	dependent functions.
218  */
219 void
220 vm_set_page_size(void)
221 {
222 	if (vm_cnt.v_page_size == 0)
223 		vm_cnt.v_page_size = PAGE_SIZE;
224 	if (((vm_cnt.v_page_size - 1) & vm_cnt.v_page_size) != 0)
225 		panic("vm_set_page_size: page size not a power of two");
226 }
227 
228 /*
229  *	vm_page_blacklist_next:
230  *
231  *	Find the next entry in the provided string of blacklist
232  *	addresses.  Entries are separated by space, comma, or newline.
233  *	If an invalid integer is encountered then the rest of the
234  *	string is skipped.  Updates the list pointer to the next
235  *	character, or NULL if the string is exhausted or invalid.
236  */
237 static vm_paddr_t
238 vm_page_blacklist_next(char **list, char *end)
239 {
240 	vm_paddr_t bad;
241 	char *cp, *pos;
242 
243 	if (list == NULL || *list == NULL)
244 		return (0);
245 	if (**list =='\0') {
246 		*list = NULL;
247 		return (0);
248 	}
249 
250 	/*
251 	 * If there's no end pointer then the buffer is coming from
252 	 * the kenv and we know it's null-terminated.
253 	 */
254 	if (end == NULL)
255 		end = *list + strlen(*list);
256 
257 	/* Ensure that strtoq() won't walk off the end */
258 	if (*end != '\0') {
259 		if (*end == '\n' || *end == ' ' || *end  == ',')
260 			*end = '\0';
261 		else {
262 			printf("Blacklist not terminated, skipping\n");
263 			*list = NULL;
264 			return (0);
265 		}
266 	}
267 
268 	for (pos = *list; *pos != '\0'; pos = cp) {
269 		bad = strtoq(pos, &cp, 0);
270 		if (*cp == '\0' || *cp == ' ' || *cp == ',' || *cp == '\n') {
271 			if (bad == 0) {
272 				if (++cp < end)
273 					continue;
274 				else
275 					break;
276 			}
277 		} else
278 			break;
279 		if (*cp == '\0' || ++cp >= end)
280 			*list = NULL;
281 		else
282 			*list = cp;
283 		return (trunc_page(bad));
284 	}
285 	printf("Garbage in RAM blacklist, skipping\n");
286 	*list = NULL;
287 	return (0);
288 }
289 
290 /*
291  *	vm_page_blacklist_check:
292  *
293  *	Iterate through the provided string of blacklist addresses, pulling
294  *	each entry out of the physical allocator free list and putting it
295  *	onto a list for reporting via the vm.page_blacklist sysctl.
296  */
297 static void
298 vm_page_blacklist_check(char *list, char *end)
299 {
300 	vm_paddr_t pa;
301 	vm_page_t m;
302 	char *next;
303 	int ret;
304 
305 	next = list;
306 	while (next != NULL) {
307 		if ((pa = vm_page_blacklist_next(&next, end)) == 0)
308 			continue;
309 		m = vm_phys_paddr_to_vm_page(pa);
310 		if (m == NULL)
311 			continue;
312 		mtx_lock(&vm_page_queue_free_mtx);
313 		ret = vm_phys_unfree_page(m);
314 		mtx_unlock(&vm_page_queue_free_mtx);
315 		if (ret == TRUE) {
316 			TAILQ_INSERT_TAIL(&blacklist_head, m, listq);
317 			if (bootverbose)
318 				printf("Skipping page with pa 0x%jx\n",
319 				    (uintmax_t)pa);
320 		}
321 	}
322 }
323 
324 /*
325  *	vm_page_blacklist_load:
326  *
327  *	Search for a special module named "ram_blacklist".  It'll be a
328  *	plain text file provided by the user via the loader directive
329  *	of the same name.
330  */
331 static void
332 vm_page_blacklist_load(char **list, char **end)
333 {
334 	void *mod;
335 	u_char *ptr;
336 	u_int len;
337 
338 	mod = NULL;
339 	ptr = NULL;
340 
341 	mod = preload_search_by_type("ram_blacklist");
342 	if (mod != NULL) {
343 		ptr = preload_fetch_addr(mod);
344 		len = preload_fetch_size(mod);
345         }
346 	*list = ptr;
347 	if (ptr != NULL)
348 		*end = ptr + len;
349 	else
350 		*end = NULL;
351 	return;
352 }
353 
354 static int
355 sysctl_vm_page_blacklist(SYSCTL_HANDLER_ARGS)
356 {
357 	vm_page_t m;
358 	struct sbuf sbuf;
359 	int error, first;
360 
361 	first = 1;
362 	error = sysctl_wire_old_buffer(req, 0);
363 	if (error != 0)
364 		return (error);
365 	sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
366 	TAILQ_FOREACH(m, &blacklist_head, listq) {
367 		sbuf_printf(&sbuf, "%s%#jx", first ? "" : ",",
368 		    (uintmax_t)m->phys_addr);
369 		first = 0;
370 	}
371 	error = sbuf_finish(&sbuf);
372 	sbuf_delete(&sbuf);
373 	return (error);
374 }
375 
376 static void
377 vm_page_domain_init(struct vm_domain *vmd)
378 {
379 	struct vm_pagequeue *pq;
380 	int i;
381 
382 	*__DECONST(char **, &vmd->vmd_pagequeues[PQ_INACTIVE].pq_name) =
383 	    "vm inactive pagequeue";
384 	*__DECONST(int **, &vmd->vmd_pagequeues[PQ_INACTIVE].pq_vcnt) =
385 	    &vm_cnt.v_inactive_count;
386 	*__DECONST(char **, &vmd->vmd_pagequeues[PQ_ACTIVE].pq_name) =
387 	    "vm active pagequeue";
388 	*__DECONST(int **, &vmd->vmd_pagequeues[PQ_ACTIVE].pq_vcnt) =
389 	    &vm_cnt.v_active_count;
390 	vmd->vmd_page_count = 0;
391 	vmd->vmd_free_count = 0;
392 	vmd->vmd_segs = 0;
393 	vmd->vmd_oom = FALSE;
394 	vmd->vmd_pass = 0;
395 	for (i = 0; i < PQ_COUNT; i++) {
396 		pq = &vmd->vmd_pagequeues[i];
397 		TAILQ_INIT(&pq->pq_pl);
398 		mtx_init(&pq->pq_mutex, pq->pq_name, "vm pagequeue",
399 		    MTX_DEF | MTX_DUPOK);
400 	}
401 }
402 
403 /*
404  *	vm_page_startup:
405  *
406  *	Initializes the resident memory module.
407  *
408  *	Allocates memory for the page cells, and
409  *	for the object/offset-to-page hash table headers.
410  *	Each page cell is initialized and placed on the free list.
411  */
412 vm_offset_t
413 vm_page_startup(vm_offset_t vaddr)
414 {
415 	vm_offset_t mapped;
416 	vm_paddr_t page_range;
417 	vm_paddr_t new_end;
418 	int i;
419 	vm_paddr_t pa;
420 	vm_paddr_t last_pa;
421 	char *list, *listend;
422 	vm_paddr_t end;
423 	vm_paddr_t biggestsize;
424 	vm_paddr_t low_water, high_water;
425 	int biggestone;
426 
427 	biggestsize = 0;
428 	biggestone = 0;
429 	vaddr = round_page(vaddr);
430 
431 	for (i = 0; phys_avail[i + 1]; i += 2) {
432 		phys_avail[i] = round_page(phys_avail[i]);
433 		phys_avail[i + 1] = trunc_page(phys_avail[i + 1]);
434 	}
435 
436 	low_water = phys_avail[0];
437 	high_water = phys_avail[1];
438 
439 	for (i = 0; i < vm_phys_nsegs; i++) {
440 		if (vm_phys_segs[i].start < low_water)
441 			low_water = vm_phys_segs[i].start;
442 		if (vm_phys_segs[i].end > high_water)
443 			high_water = vm_phys_segs[i].end;
444 	}
445 	for (i = 0; phys_avail[i + 1]; i += 2) {
446 		vm_paddr_t size = phys_avail[i + 1] - phys_avail[i];
447 
448 		if (size > biggestsize) {
449 			biggestone = i;
450 			biggestsize = size;
451 		}
452 		if (phys_avail[i] < low_water)
453 			low_water = phys_avail[i];
454 		if (phys_avail[i + 1] > high_water)
455 			high_water = phys_avail[i + 1];
456 	}
457 
458 	end = phys_avail[biggestone+1];
459 
460 	/*
461 	 * Initialize the page and queue locks.
462 	 */
463 	mtx_init(&vm_page_queue_free_mtx, "vm page free queue", NULL, MTX_DEF);
464 	for (i = 0; i < PA_LOCK_COUNT; i++)
465 		mtx_init(&pa_lock[i], "vm page", NULL, MTX_DEF);
466 	for (i = 0; i < vm_ndomains; i++)
467 		vm_page_domain_init(&vm_dom[i]);
468 
469 	/*
470 	 * Allocate memory for use when boot strapping the kernel memory
471 	 * allocator.
472 	 *
473 	 * CTFLAG_RDTUN doesn't work during the early boot process, so we must
474 	 * manually fetch the value.
475 	 */
476 	TUNABLE_INT_FETCH("vm.boot_pages", &boot_pages);
477 	new_end = end - (boot_pages * UMA_SLAB_SIZE);
478 	new_end = trunc_page(new_end);
479 	mapped = pmap_map(&vaddr, new_end, end,
480 	    VM_PROT_READ | VM_PROT_WRITE);
481 	bzero((void *)mapped, end - new_end);
482 	uma_startup((void *)mapped, boot_pages);
483 
484 #if defined(__aarch64__) || defined(__amd64__) || defined(__arm__) || \
485     defined(__i386__) || defined(__mips__)
486 	/*
487 	 * Allocate a bitmap to indicate that a random physical page
488 	 * needs to be included in a minidump.
489 	 *
490 	 * The amd64 port needs this to indicate which direct map pages
491 	 * need to be dumped, via calls to dump_add_page()/dump_drop_page().
492 	 *
493 	 * However, i386 still needs this workspace internally within the
494 	 * minidump code.  In theory, they are not needed on i386, but are
495 	 * included should the sf_buf code decide to use them.
496 	 */
497 	last_pa = 0;
498 	for (i = 0; dump_avail[i + 1] != 0; i += 2)
499 		if (dump_avail[i + 1] > last_pa)
500 			last_pa = dump_avail[i + 1];
501 	page_range = last_pa / PAGE_SIZE;
502 	vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY);
503 	new_end -= vm_page_dump_size;
504 	vm_page_dump = (void *)(uintptr_t)pmap_map(&vaddr, new_end,
505 	    new_end + vm_page_dump_size, VM_PROT_READ | VM_PROT_WRITE);
506 	bzero((void *)vm_page_dump, vm_page_dump_size);
507 #endif
508 #ifdef __amd64__
509 	/*
510 	 * Request that the physical pages underlying the message buffer be
511 	 * included in a crash dump.  Since the message buffer is accessed
512 	 * through the direct map, they are not automatically included.
513 	 */
514 	pa = DMAP_TO_PHYS((vm_offset_t)msgbufp->msg_ptr);
515 	last_pa = pa + round_page(msgbufsize);
516 	while (pa < last_pa) {
517 		dump_add_page(pa);
518 		pa += PAGE_SIZE;
519 	}
520 #endif
521 	/*
522 	 * Compute the number of pages of memory that will be available for
523 	 * use (taking into account the overhead of a page structure per
524 	 * page).
525 	 */
526 	first_page = low_water / PAGE_SIZE;
527 #ifdef VM_PHYSSEG_SPARSE
528 	page_range = 0;
529 	for (i = 0; i < vm_phys_nsegs; i++) {
530 		page_range += atop(vm_phys_segs[i].end -
531 		    vm_phys_segs[i].start);
532 	}
533 	for (i = 0; phys_avail[i + 1] != 0; i += 2)
534 		page_range += atop(phys_avail[i + 1] - phys_avail[i]);
535 #elif defined(VM_PHYSSEG_DENSE)
536 	page_range = high_water / PAGE_SIZE - first_page;
537 #else
538 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined."
539 #endif
540 	end = new_end;
541 
542 	/*
543 	 * Reserve an unmapped guard page to trap access to vm_page_array[-1].
544 	 */
545 	vaddr += PAGE_SIZE;
546 
547 	/*
548 	 * Initialize the mem entry structures now, and put them in the free
549 	 * queue.
550 	 */
551 	new_end = trunc_page(end - page_range * sizeof(struct vm_page));
552 	mapped = pmap_map(&vaddr, new_end, end,
553 	    VM_PROT_READ | VM_PROT_WRITE);
554 	vm_page_array = (vm_page_t) mapped;
555 #if VM_NRESERVLEVEL > 0
556 	/*
557 	 * Allocate memory for the reservation management system's data
558 	 * structures.
559 	 */
560 	new_end = vm_reserv_startup(&vaddr, new_end, high_water);
561 #endif
562 #if defined(__aarch64__) || defined(__amd64__) || defined(__mips__)
563 	/*
564 	 * pmap_map on arm64, amd64, and mips can come out of the direct-map,
565 	 * not kvm like i386, so the pages must be tracked for a crashdump to
566 	 * include this data.  This includes the vm_page_array and the early
567 	 * UMA bootstrap pages.
568 	 */
569 	for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE)
570 		dump_add_page(pa);
571 #endif
572 	phys_avail[biggestone + 1] = new_end;
573 
574 	/*
575 	 * Add physical memory segments corresponding to the available
576 	 * physical pages.
577 	 */
578 	for (i = 0; phys_avail[i + 1] != 0; i += 2)
579 		vm_phys_add_seg(phys_avail[i], phys_avail[i + 1]);
580 
581 	/*
582 	 * Clear all of the page structures
583 	 */
584 	bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page));
585 	for (i = 0; i < page_range; i++)
586 		vm_page_array[i].order = VM_NFREEORDER;
587 	vm_page_array_size = page_range;
588 
589 	/*
590 	 * Initialize the physical memory allocator.
591 	 */
592 	vm_phys_init();
593 
594 	/*
595 	 * Add every available physical page that is not blacklisted to
596 	 * the free lists.
597 	 */
598 	vm_cnt.v_page_count = 0;
599 	vm_cnt.v_free_count = 0;
600 	for (i = 0; phys_avail[i + 1] != 0; i += 2) {
601 		pa = phys_avail[i];
602 		last_pa = phys_avail[i + 1];
603 		while (pa < last_pa) {
604 			vm_phys_add_page(pa);
605 			pa += PAGE_SIZE;
606 		}
607 	}
608 
609 	TAILQ_INIT(&blacklist_head);
610 	vm_page_blacklist_load(&list, &listend);
611 	vm_page_blacklist_check(list, listend);
612 
613 	list = kern_getenv("vm.blacklist");
614 	vm_page_blacklist_check(list, NULL);
615 
616 	freeenv(list);
617 #if VM_NRESERVLEVEL > 0
618 	/*
619 	 * Initialize the reservation management system.
620 	 */
621 	vm_reserv_init();
622 #endif
623 	return (vaddr);
624 }
625 
626 void
627 vm_page_reference(vm_page_t m)
628 {
629 
630 	vm_page_aflag_set(m, PGA_REFERENCED);
631 }
632 
633 /*
634  *	vm_page_busy_downgrade:
635  *
636  *	Downgrade an exclusive busy page into a single shared busy page.
637  */
638 void
639 vm_page_busy_downgrade(vm_page_t m)
640 {
641 	u_int x;
642 
643 	vm_page_assert_xbusied(m);
644 
645 	for (;;) {
646 		x = m->busy_lock;
647 		x &= VPB_BIT_WAITERS;
648 		if (atomic_cmpset_rel_int(&m->busy_lock,
649 		    VPB_SINGLE_EXCLUSIVER | x, VPB_SHARERS_WORD(1) | x))
650 			break;
651 	}
652 }
653 
654 /*
655  *	vm_page_sbusied:
656  *
657  *	Return a positive value if the page is shared busied, 0 otherwise.
658  */
659 int
660 vm_page_sbusied(vm_page_t m)
661 {
662 	u_int x;
663 
664 	x = m->busy_lock;
665 	return ((x & VPB_BIT_SHARED) != 0 && x != VPB_UNBUSIED);
666 }
667 
668 /*
669  *	vm_page_sunbusy:
670  *
671  *	Shared unbusy a page.
672  */
673 void
674 vm_page_sunbusy(vm_page_t m)
675 {
676 	u_int x;
677 
678 	vm_page_assert_sbusied(m);
679 
680 	for (;;) {
681 		x = m->busy_lock;
682 		if (VPB_SHARERS(x) > 1) {
683 			if (atomic_cmpset_int(&m->busy_lock, x,
684 			    x - VPB_ONE_SHARER))
685 				break;
686 			continue;
687 		}
688 		if ((x & VPB_BIT_WAITERS) == 0) {
689 			KASSERT(x == VPB_SHARERS_WORD(1),
690 			    ("vm_page_sunbusy: invalid lock state"));
691 			if (atomic_cmpset_int(&m->busy_lock,
692 			    VPB_SHARERS_WORD(1), VPB_UNBUSIED))
693 				break;
694 			continue;
695 		}
696 		KASSERT(x == (VPB_SHARERS_WORD(1) | VPB_BIT_WAITERS),
697 		    ("vm_page_sunbusy: invalid lock state for waiters"));
698 
699 		vm_page_lock(m);
700 		if (!atomic_cmpset_int(&m->busy_lock, x, VPB_UNBUSIED)) {
701 			vm_page_unlock(m);
702 			continue;
703 		}
704 		wakeup(m);
705 		vm_page_unlock(m);
706 		break;
707 	}
708 }
709 
710 /*
711  *	vm_page_busy_sleep:
712  *
713  *	Sleep and release the page lock, using the page pointer as wchan.
714  *	This is used to implement the hard-path of busying mechanism.
715  *
716  *	The given page must be locked.
717  */
718 void
719 vm_page_busy_sleep(vm_page_t m, const char *wmesg)
720 {
721 	u_int x;
722 
723 	vm_page_lock_assert(m, MA_OWNED);
724 
725 	x = m->busy_lock;
726 	if (x == VPB_UNBUSIED) {
727 		vm_page_unlock(m);
728 		return;
729 	}
730 	if ((x & VPB_BIT_WAITERS) == 0 &&
731 	    !atomic_cmpset_int(&m->busy_lock, x, x | VPB_BIT_WAITERS)) {
732 		vm_page_unlock(m);
733 		return;
734 	}
735 	msleep(m, vm_page_lockptr(m), PVM | PDROP, wmesg, 0);
736 }
737 
738 /*
739  *	vm_page_trysbusy:
740  *
741  *	Try to shared busy a page.
742  *	If the operation succeeds 1 is returned otherwise 0.
743  *	The operation never sleeps.
744  */
745 int
746 vm_page_trysbusy(vm_page_t m)
747 {
748 	u_int x;
749 
750 	for (;;) {
751 		x = m->busy_lock;
752 		if ((x & VPB_BIT_SHARED) == 0)
753 			return (0);
754 		if (atomic_cmpset_acq_int(&m->busy_lock, x, x + VPB_ONE_SHARER))
755 			return (1);
756 	}
757 }
758 
759 /*
760  *	vm_page_xunbusy_hard:
761  *
762  *	Called after the first try the exclusive unbusy of a page failed.
763  *	It is assumed that the waiters bit is on.
764  */
765 void
766 vm_page_xunbusy_hard(vm_page_t m)
767 {
768 
769 	vm_page_assert_xbusied(m);
770 
771 	vm_page_lock(m);
772 	atomic_store_rel_int(&m->busy_lock, VPB_UNBUSIED);
773 	wakeup(m);
774 	vm_page_unlock(m);
775 }
776 
777 /*
778  *	vm_page_flash:
779  *
780  *	Wakeup anyone waiting for the page.
781  *	The ownership bits do not change.
782  *
783  *	The given page must be locked.
784  */
785 void
786 vm_page_flash(vm_page_t m)
787 {
788 	u_int x;
789 
790 	vm_page_lock_assert(m, MA_OWNED);
791 
792 	for (;;) {
793 		x = m->busy_lock;
794 		if ((x & VPB_BIT_WAITERS) == 0)
795 			return;
796 		if (atomic_cmpset_int(&m->busy_lock, x,
797 		    x & (~VPB_BIT_WAITERS)))
798 			break;
799 	}
800 	wakeup(m);
801 }
802 
803 /*
804  * Keep page from being freed by the page daemon
805  * much of the same effect as wiring, except much lower
806  * overhead and should be used only for *very* temporary
807  * holding ("wiring").
808  */
809 void
810 vm_page_hold(vm_page_t mem)
811 {
812 
813 	vm_page_lock_assert(mem, MA_OWNED);
814         mem->hold_count++;
815 }
816 
817 void
818 vm_page_unhold(vm_page_t mem)
819 {
820 
821 	vm_page_lock_assert(mem, MA_OWNED);
822 	KASSERT(mem->hold_count >= 1, ("vm_page_unhold: hold count < 0!!!"));
823 	--mem->hold_count;
824 	if (mem->hold_count == 0 && (mem->flags & PG_UNHOLDFREE) != 0)
825 		vm_page_free_toq(mem);
826 }
827 
828 /*
829  *	vm_page_unhold_pages:
830  *
831  *	Unhold each of the pages that is referenced by the given array.
832  */
833 void
834 vm_page_unhold_pages(vm_page_t *ma, int count)
835 {
836 	struct mtx *mtx, *new_mtx;
837 
838 	mtx = NULL;
839 	for (; count != 0; count--) {
840 		/*
841 		 * Avoid releasing and reacquiring the same page lock.
842 		 */
843 		new_mtx = vm_page_lockptr(*ma);
844 		if (mtx != new_mtx) {
845 			if (mtx != NULL)
846 				mtx_unlock(mtx);
847 			mtx = new_mtx;
848 			mtx_lock(mtx);
849 		}
850 		vm_page_unhold(*ma);
851 		ma++;
852 	}
853 	if (mtx != NULL)
854 		mtx_unlock(mtx);
855 }
856 
857 vm_page_t
858 PHYS_TO_VM_PAGE(vm_paddr_t pa)
859 {
860 	vm_page_t m;
861 
862 #ifdef VM_PHYSSEG_SPARSE
863 	m = vm_phys_paddr_to_vm_page(pa);
864 	if (m == NULL)
865 		m = vm_phys_fictitious_to_vm_page(pa);
866 	return (m);
867 #elif defined(VM_PHYSSEG_DENSE)
868 	long pi;
869 
870 	pi = atop(pa);
871 	if (pi >= first_page && (pi - first_page) < vm_page_array_size) {
872 		m = &vm_page_array[pi - first_page];
873 		return (m);
874 	}
875 	return (vm_phys_fictitious_to_vm_page(pa));
876 #else
877 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined."
878 #endif
879 }
880 
881 /*
882  *	vm_page_getfake:
883  *
884  *	Create a fictitious page with the specified physical address and
885  *	memory attribute.  The memory attribute is the only the machine-
886  *	dependent aspect of a fictitious page that must be initialized.
887  */
888 vm_page_t
889 vm_page_getfake(vm_paddr_t paddr, vm_memattr_t memattr)
890 {
891 	vm_page_t m;
892 
893 	m = uma_zalloc(fakepg_zone, M_WAITOK | M_ZERO);
894 	vm_page_initfake(m, paddr, memattr);
895 	return (m);
896 }
897 
898 void
899 vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
900 {
901 
902 	if ((m->flags & PG_FICTITIOUS) != 0) {
903 		/*
904 		 * The page's memattr might have changed since the
905 		 * previous initialization.  Update the pmap to the
906 		 * new memattr.
907 		 */
908 		goto memattr;
909 	}
910 	m->phys_addr = paddr;
911 	m->queue = PQ_NONE;
912 	/* Fictitious pages don't use "segind". */
913 	m->flags = PG_FICTITIOUS;
914 	/* Fictitious pages don't use "order" or "pool". */
915 	m->oflags = VPO_UNMANAGED;
916 	m->busy_lock = VPB_SINGLE_EXCLUSIVER;
917 	m->wire_count = 1;
918 	pmap_page_init(m);
919 memattr:
920 	pmap_page_set_memattr(m, memattr);
921 }
922 
923 /*
924  *	vm_page_putfake:
925  *
926  *	Release a fictitious page.
927  */
928 void
929 vm_page_putfake(vm_page_t m)
930 {
931 
932 	KASSERT((m->oflags & VPO_UNMANAGED) != 0, ("managed %p", m));
933 	KASSERT((m->flags & PG_FICTITIOUS) != 0,
934 	    ("vm_page_putfake: bad page %p", m));
935 	uma_zfree(fakepg_zone, m);
936 }
937 
938 /*
939  *	vm_page_updatefake:
940  *
941  *	Update the given fictitious page to the specified physical address and
942  *	memory attribute.
943  */
944 void
945 vm_page_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
946 {
947 
948 	KASSERT((m->flags & PG_FICTITIOUS) != 0,
949 	    ("vm_page_updatefake: bad page %p", m));
950 	m->phys_addr = paddr;
951 	pmap_page_set_memattr(m, memattr);
952 }
953 
954 /*
955  *	vm_page_free:
956  *
957  *	Free a page.
958  */
959 void
960 vm_page_free(vm_page_t m)
961 {
962 
963 	m->flags &= ~PG_ZERO;
964 	vm_page_free_toq(m);
965 }
966 
967 /*
968  *	vm_page_free_zero:
969  *
970  *	Free a page to the zerod-pages queue
971  */
972 void
973 vm_page_free_zero(vm_page_t m)
974 {
975 
976 	m->flags |= PG_ZERO;
977 	vm_page_free_toq(m);
978 }
979 
980 /*
981  * Unbusy and handle the page queueing for a page from the VOP_GETPAGES()
982  * array which is not the request page.
983  */
984 void
985 vm_page_readahead_finish(vm_page_t m)
986 {
987 
988 	if (m->valid != 0) {
989 		/*
990 		 * Since the page is not the requested page, whether
991 		 * it should be activated or deactivated is not
992 		 * obvious.  Empirical results have shown that
993 		 * deactivating the page is usually the best choice,
994 		 * unless the page is wanted by another thread.
995 		 */
996 		vm_page_lock(m);
997 		if ((m->busy_lock & VPB_BIT_WAITERS) != 0)
998 			vm_page_activate(m);
999 		else
1000 			vm_page_deactivate(m);
1001 		vm_page_unlock(m);
1002 		vm_page_xunbusy(m);
1003 	} else {
1004 		/*
1005 		 * Free the completely invalid page.  Such page state
1006 		 * occurs due to the short read operation which did
1007 		 * not covered our page at all, or in case when a read
1008 		 * error happens.
1009 		 */
1010 		vm_page_lock(m);
1011 		vm_page_free(m);
1012 		vm_page_unlock(m);
1013 	}
1014 }
1015 
1016 /*
1017  *	vm_page_sleep_if_busy:
1018  *
1019  *	Sleep and release the page queues lock if the page is busied.
1020  *	Returns TRUE if the thread slept.
1021  *
1022  *	The given page must be unlocked and object containing it must
1023  *	be locked.
1024  */
1025 int
1026 vm_page_sleep_if_busy(vm_page_t m, const char *msg)
1027 {
1028 	vm_object_t obj;
1029 
1030 	vm_page_lock_assert(m, MA_NOTOWNED);
1031 	VM_OBJECT_ASSERT_WLOCKED(m->object);
1032 
1033 	if (vm_page_busied(m)) {
1034 		/*
1035 		 * The page-specific object must be cached because page
1036 		 * identity can change during the sleep, causing the
1037 		 * re-lock of a different object.
1038 		 * It is assumed that a reference to the object is already
1039 		 * held by the callers.
1040 		 */
1041 		obj = m->object;
1042 		vm_page_lock(m);
1043 		VM_OBJECT_WUNLOCK(obj);
1044 		vm_page_busy_sleep(m, msg);
1045 		VM_OBJECT_WLOCK(obj);
1046 		return (TRUE);
1047 	}
1048 	return (FALSE);
1049 }
1050 
1051 /*
1052  *	vm_page_dirty_KBI:		[ internal use only ]
1053  *
1054  *	Set all bits in the page's dirty field.
1055  *
1056  *	The object containing the specified page must be locked if the
1057  *	call is made from the machine-independent layer.
1058  *
1059  *	See vm_page_clear_dirty_mask().
1060  *
1061  *	This function should only be called by vm_page_dirty().
1062  */
1063 void
1064 vm_page_dirty_KBI(vm_page_t m)
1065 {
1066 
1067 	/* These assertions refer to this operation by its public name. */
1068 	KASSERT((m->flags & PG_CACHED) == 0,
1069 	    ("vm_page_dirty: page in cache!"));
1070 	KASSERT(m->valid == VM_PAGE_BITS_ALL,
1071 	    ("vm_page_dirty: page is invalid!"));
1072 	m->dirty = VM_PAGE_BITS_ALL;
1073 }
1074 
1075 /*
1076  *	vm_page_insert:		[ internal use only ]
1077  *
1078  *	Inserts the given mem entry into the object and object list.
1079  *
1080  *	The object must be locked.
1081  */
1082 int
1083 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
1084 {
1085 	vm_page_t mpred;
1086 
1087 	VM_OBJECT_ASSERT_WLOCKED(object);
1088 	mpred = vm_radix_lookup_le(&object->rtree, pindex);
1089 	return (vm_page_insert_after(m, object, pindex, mpred));
1090 }
1091 
1092 /*
1093  *	vm_page_insert_after:
1094  *
1095  *	Inserts the page "m" into the specified object at offset "pindex".
1096  *
1097  *	The page "mpred" must immediately precede the offset "pindex" within
1098  *	the specified object.
1099  *
1100  *	The object must be locked.
1101  */
1102 static int
1103 vm_page_insert_after(vm_page_t m, vm_object_t object, vm_pindex_t pindex,
1104     vm_page_t mpred)
1105 {
1106 	vm_pindex_t sidx;
1107 	vm_object_t sobj;
1108 	vm_page_t msucc;
1109 
1110 	VM_OBJECT_ASSERT_WLOCKED(object);
1111 	KASSERT(m->object == NULL,
1112 	    ("vm_page_insert_after: page already inserted"));
1113 	if (mpred != NULL) {
1114 		KASSERT(mpred->object == object,
1115 		    ("vm_page_insert_after: object doesn't contain mpred"));
1116 		KASSERT(mpred->pindex < pindex,
1117 		    ("vm_page_insert_after: mpred doesn't precede pindex"));
1118 		msucc = TAILQ_NEXT(mpred, listq);
1119 	} else
1120 		msucc = TAILQ_FIRST(&object->memq);
1121 	if (msucc != NULL)
1122 		KASSERT(msucc->pindex > pindex,
1123 		    ("vm_page_insert_after: msucc doesn't succeed pindex"));
1124 
1125 	/*
1126 	 * Record the object/offset pair in this page
1127 	 */
1128 	sobj = m->object;
1129 	sidx = m->pindex;
1130 	m->object = object;
1131 	m->pindex = pindex;
1132 
1133 	/*
1134 	 * Now link into the object's ordered list of backed pages.
1135 	 */
1136 	if (vm_radix_insert(&object->rtree, m)) {
1137 		m->object = sobj;
1138 		m->pindex = sidx;
1139 		return (1);
1140 	}
1141 	vm_page_insert_radixdone(m, object, mpred);
1142 	return (0);
1143 }
1144 
1145 /*
1146  *	vm_page_insert_radixdone:
1147  *
1148  *	Complete page "m" insertion into the specified object after the
1149  *	radix trie hooking.
1150  *
1151  *	The page "mpred" must precede the offset "m->pindex" within the
1152  *	specified object.
1153  *
1154  *	The object must be locked.
1155  */
1156 static void
1157 vm_page_insert_radixdone(vm_page_t m, vm_object_t object, vm_page_t mpred)
1158 {
1159 
1160 	VM_OBJECT_ASSERT_WLOCKED(object);
1161 	KASSERT(object != NULL && m->object == object,
1162 	    ("vm_page_insert_radixdone: page %p has inconsistent object", m));
1163 	if (mpred != NULL) {
1164 		KASSERT(mpred->object == object,
1165 		    ("vm_page_insert_after: object doesn't contain mpred"));
1166 		KASSERT(mpred->pindex < m->pindex,
1167 		    ("vm_page_insert_after: mpred doesn't precede pindex"));
1168 	}
1169 
1170 	if (mpred != NULL)
1171 		TAILQ_INSERT_AFTER(&object->memq, mpred, m, listq);
1172 	else
1173 		TAILQ_INSERT_HEAD(&object->memq, m, listq);
1174 
1175 	/*
1176 	 * Show that the object has one more resident page.
1177 	 */
1178 	object->resident_page_count++;
1179 
1180 	/*
1181 	 * Hold the vnode until the last page is released.
1182 	 */
1183 	if (object->resident_page_count == 1 && object->type == OBJT_VNODE)
1184 		vhold(object->handle);
1185 
1186 	/*
1187 	 * Since we are inserting a new and possibly dirty page,
1188 	 * update the object's OBJ_MIGHTBEDIRTY flag.
1189 	 */
1190 	if (pmap_page_is_write_mapped(m))
1191 		vm_object_set_writeable_dirty(object);
1192 }
1193 
1194 /*
1195  *	vm_page_remove:
1196  *
1197  *	Removes the given mem entry from the object/offset-page
1198  *	table and the object page list, but do not invalidate/terminate
1199  *	the backing store.
1200  *
1201  *	The object must be locked.  The page must be locked if it is managed.
1202  */
1203 void
1204 vm_page_remove(vm_page_t m)
1205 {
1206 	vm_object_t object;
1207 	boolean_t lockacq;
1208 
1209 	if ((m->oflags & VPO_UNMANAGED) == 0)
1210 		vm_page_lock_assert(m, MA_OWNED);
1211 	if ((object = m->object) == NULL)
1212 		return;
1213 	VM_OBJECT_ASSERT_WLOCKED(object);
1214 	if (vm_page_xbusied(m)) {
1215 		lockacq = FALSE;
1216 		if ((m->oflags & VPO_UNMANAGED) != 0 &&
1217 		    !mtx_owned(vm_page_lockptr(m))) {
1218 			lockacq = TRUE;
1219 			vm_page_lock(m);
1220 		}
1221 		vm_page_flash(m);
1222 		atomic_store_rel_int(&m->busy_lock, VPB_UNBUSIED);
1223 		if (lockacq)
1224 			vm_page_unlock(m);
1225 	}
1226 
1227 	/*
1228 	 * Now remove from the object's list of backed pages.
1229 	 */
1230 	vm_radix_remove(&object->rtree, m->pindex);
1231 	TAILQ_REMOVE(&object->memq, m, listq);
1232 
1233 	/*
1234 	 * And show that the object has one fewer resident page.
1235 	 */
1236 	object->resident_page_count--;
1237 
1238 	/*
1239 	 * The vnode may now be recycled.
1240 	 */
1241 	if (object->resident_page_count == 0 && object->type == OBJT_VNODE)
1242 		vdrop(object->handle);
1243 
1244 	m->object = NULL;
1245 }
1246 
1247 /*
1248  *	vm_page_lookup:
1249  *
1250  *	Returns the page associated with the object/offset
1251  *	pair specified; if none is found, NULL is returned.
1252  *
1253  *	The object must be locked.
1254  */
1255 vm_page_t
1256 vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
1257 {
1258 
1259 	VM_OBJECT_ASSERT_LOCKED(object);
1260 	return (vm_radix_lookup(&object->rtree, pindex));
1261 }
1262 
1263 /*
1264  *	vm_page_find_least:
1265  *
1266  *	Returns the page associated with the object with least pindex
1267  *	greater than or equal to the parameter pindex, or NULL.
1268  *
1269  *	The object must be locked.
1270  */
1271 vm_page_t
1272 vm_page_find_least(vm_object_t object, vm_pindex_t pindex)
1273 {
1274 	vm_page_t m;
1275 
1276 	VM_OBJECT_ASSERT_LOCKED(object);
1277 	if ((m = TAILQ_FIRST(&object->memq)) != NULL && m->pindex < pindex)
1278 		m = vm_radix_lookup_ge(&object->rtree, pindex);
1279 	return (m);
1280 }
1281 
1282 /*
1283  * Returns the given page's successor (by pindex) within the object if it is
1284  * resident; if none is found, NULL is returned.
1285  *
1286  * The object must be locked.
1287  */
1288 vm_page_t
1289 vm_page_next(vm_page_t m)
1290 {
1291 	vm_page_t next;
1292 
1293 	VM_OBJECT_ASSERT_WLOCKED(m->object);
1294 	if ((next = TAILQ_NEXT(m, listq)) != NULL &&
1295 	    next->pindex != m->pindex + 1)
1296 		next = NULL;
1297 	return (next);
1298 }
1299 
1300 /*
1301  * Returns the given page's predecessor (by pindex) within the object if it is
1302  * resident; if none is found, NULL is returned.
1303  *
1304  * The object must be locked.
1305  */
1306 vm_page_t
1307 vm_page_prev(vm_page_t m)
1308 {
1309 	vm_page_t prev;
1310 
1311 	VM_OBJECT_ASSERT_WLOCKED(m->object);
1312 	if ((prev = TAILQ_PREV(m, pglist, listq)) != NULL &&
1313 	    prev->pindex != m->pindex - 1)
1314 		prev = NULL;
1315 	return (prev);
1316 }
1317 
1318 /*
1319  * Uses the page mnew as a replacement for an existing page at index
1320  * pindex which must be already present in the object.
1321  *
1322  * The existing page must not be on a paging queue.
1323  */
1324 vm_page_t
1325 vm_page_replace(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex)
1326 {
1327 	vm_page_t mold, mpred;
1328 
1329 	VM_OBJECT_ASSERT_WLOCKED(object);
1330 
1331 	/*
1332 	 * This function mostly follows vm_page_insert() and
1333 	 * vm_page_remove() without the radix, object count and vnode
1334 	 * dance.  Double check such functions for more comments.
1335 	 */
1336 	mpred = vm_radix_lookup(&object->rtree, pindex);
1337 	KASSERT(mpred != NULL,
1338 	    ("vm_page_replace: replacing page not present with pindex"));
1339 	mpred = TAILQ_PREV(mpred, respgs, listq);
1340 	if (mpred != NULL)
1341 		KASSERT(mpred->pindex < pindex,
1342 		    ("vm_page_insert_after: mpred doesn't precede pindex"));
1343 
1344 	mnew->object = object;
1345 	mnew->pindex = pindex;
1346 	mold = vm_radix_replace(&object->rtree, mnew);
1347 	KASSERT(mold->queue == PQ_NONE,
1348 	    ("vm_page_replace: mold is on a paging queue"));
1349 
1350 	/* Detach the old page from the resident tailq. */
1351 	TAILQ_REMOVE(&object->memq, mold, listq);
1352 
1353 	mold->object = NULL;
1354 	vm_page_xunbusy(mold);
1355 
1356 	/* Insert the new page in the resident tailq. */
1357 	if (mpred != NULL)
1358 		TAILQ_INSERT_AFTER(&object->memq, mpred, mnew, listq);
1359 	else
1360 		TAILQ_INSERT_HEAD(&object->memq, mnew, listq);
1361 	if (pmap_page_is_write_mapped(mnew))
1362 		vm_object_set_writeable_dirty(object);
1363 	return (mold);
1364 }
1365 
1366 /*
1367  *	vm_page_rename:
1368  *
1369  *	Move the given memory entry from its
1370  *	current object to the specified target object/offset.
1371  *
1372  *	Note: swap associated with the page must be invalidated by the move.  We
1373  *	      have to do this for several reasons:  (1) we aren't freeing the
1374  *	      page, (2) we are dirtying the page, (3) the VM system is probably
1375  *	      moving the page from object A to B, and will then later move
1376  *	      the backing store from A to B and we can't have a conflict.
1377  *
1378  *	Note: we *always* dirty the page.  It is necessary both for the
1379  *	      fact that we moved it, and because we may be invalidating
1380  *	      swap.  If the page is on the cache, we have to deactivate it
1381  *	      or vm_page_dirty() will panic.  Dirty pages are not allowed
1382  *	      on the cache.
1383  *
1384  *	The objects must be locked.
1385  */
1386 int
1387 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
1388 {
1389 	vm_page_t mpred;
1390 	vm_pindex_t opidx;
1391 
1392 	VM_OBJECT_ASSERT_WLOCKED(new_object);
1393 
1394 	mpred = vm_radix_lookup_le(&new_object->rtree, new_pindex);
1395 	KASSERT(mpred == NULL || mpred->pindex != new_pindex,
1396 	    ("vm_page_rename: pindex already renamed"));
1397 
1398 	/*
1399 	 * Create a custom version of vm_page_insert() which does not depend
1400 	 * by m_prev and can cheat on the implementation aspects of the
1401 	 * function.
1402 	 */
1403 	opidx = m->pindex;
1404 	m->pindex = new_pindex;
1405 	if (vm_radix_insert(&new_object->rtree, m)) {
1406 		m->pindex = opidx;
1407 		return (1);
1408 	}
1409 
1410 	/*
1411 	 * The operation cannot fail anymore.  The removal must happen before
1412 	 * the listq iterator is tainted.
1413 	 */
1414 	m->pindex = opidx;
1415 	vm_page_lock(m);
1416 	vm_page_remove(m);
1417 
1418 	/* Return back to the new pindex to complete vm_page_insert(). */
1419 	m->pindex = new_pindex;
1420 	m->object = new_object;
1421 	vm_page_unlock(m);
1422 	vm_page_insert_radixdone(m, new_object, mpred);
1423 	vm_page_dirty(m);
1424 	return (0);
1425 }
1426 
1427 /*
1428  *	Convert all of the given object's cached pages that have a
1429  *	pindex within the given range into free pages.  If the value
1430  *	zero is given for "end", then the range's upper bound is
1431  *	infinity.  If the given object is backed by a vnode and it
1432  *	transitions from having one or more cached pages to none, the
1433  *	vnode's hold count is reduced.
1434  */
1435 void
1436 vm_page_cache_free(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
1437 {
1438 	vm_page_t m;
1439 	boolean_t empty;
1440 
1441 	mtx_lock(&vm_page_queue_free_mtx);
1442 	if (__predict_false(vm_radix_is_empty(&object->cache))) {
1443 		mtx_unlock(&vm_page_queue_free_mtx);
1444 		return;
1445 	}
1446 	while ((m = vm_radix_lookup_ge(&object->cache, start)) != NULL) {
1447 		if (end != 0 && m->pindex >= end)
1448 			break;
1449 		vm_radix_remove(&object->cache, m->pindex);
1450 		vm_page_cache_turn_free(m);
1451 	}
1452 	empty = vm_radix_is_empty(&object->cache);
1453 	mtx_unlock(&vm_page_queue_free_mtx);
1454 	if (object->type == OBJT_VNODE && empty)
1455 		vdrop(object->handle);
1456 }
1457 
1458 /*
1459  *	Returns the cached page that is associated with the given
1460  *	object and offset.  If, however, none exists, returns NULL.
1461  *
1462  *	The free page queue must be locked.
1463  */
1464 static inline vm_page_t
1465 vm_page_cache_lookup(vm_object_t object, vm_pindex_t pindex)
1466 {
1467 
1468 	mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
1469 	return (vm_radix_lookup(&object->cache, pindex));
1470 }
1471 
1472 /*
1473  *	Remove the given cached page from its containing object's
1474  *	collection of cached pages.
1475  *
1476  *	The free page queue must be locked.
1477  */
1478 static void
1479 vm_page_cache_remove(vm_page_t m)
1480 {
1481 
1482 	mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
1483 	KASSERT((m->flags & PG_CACHED) != 0,
1484 	    ("vm_page_cache_remove: page %p is not cached", m));
1485 	vm_radix_remove(&m->object->cache, m->pindex);
1486 	m->object = NULL;
1487 	vm_cnt.v_cache_count--;
1488 }
1489 
1490 /*
1491  *	Transfer all of the cached pages with offset greater than or
1492  *	equal to 'offidxstart' from the original object's cache to the
1493  *	new object's cache.  However, any cached pages with offset
1494  *	greater than or equal to the new object's size are kept in the
1495  *	original object.  Initially, the new object's cache must be
1496  *	empty.  Offset 'offidxstart' in the original object must
1497  *	correspond to offset zero in the new object.
1498  *
1499  *	The new object must be locked.
1500  */
1501 void
1502 vm_page_cache_transfer(vm_object_t orig_object, vm_pindex_t offidxstart,
1503     vm_object_t new_object)
1504 {
1505 	vm_page_t m;
1506 
1507 	/*
1508 	 * Insertion into an object's collection of cached pages
1509 	 * requires the object to be locked.  In contrast, removal does
1510 	 * not.
1511 	 */
1512 	VM_OBJECT_ASSERT_WLOCKED(new_object);
1513 	KASSERT(vm_radix_is_empty(&new_object->cache),
1514 	    ("vm_page_cache_transfer: object %p has cached pages",
1515 	    new_object));
1516 	mtx_lock(&vm_page_queue_free_mtx);
1517 	while ((m = vm_radix_lookup_ge(&orig_object->cache,
1518 	    offidxstart)) != NULL) {
1519 		/*
1520 		 * Transfer all of the pages with offset greater than or
1521 		 * equal to 'offidxstart' from the original object's
1522 		 * cache to the new object's cache.
1523 		 */
1524 		if ((m->pindex - offidxstart) >= new_object->size)
1525 			break;
1526 		vm_radix_remove(&orig_object->cache, m->pindex);
1527 		/* Update the page's object and offset. */
1528 		m->object = new_object;
1529 		m->pindex -= offidxstart;
1530 		if (vm_radix_insert(&new_object->cache, m))
1531 			vm_page_cache_turn_free(m);
1532 	}
1533 	mtx_unlock(&vm_page_queue_free_mtx);
1534 }
1535 
1536 /*
1537  *	Returns TRUE if a cached page is associated with the given object and
1538  *	offset, and FALSE otherwise.
1539  *
1540  *	The object must be locked.
1541  */
1542 boolean_t
1543 vm_page_is_cached(vm_object_t object, vm_pindex_t pindex)
1544 {
1545 	vm_page_t m;
1546 
1547 	/*
1548 	 * Insertion into an object's collection of cached pages requires the
1549 	 * object to be locked.  Therefore, if the object is locked and the
1550 	 * object's collection is empty, there is no need to acquire the free
1551 	 * page queues lock in order to prove that the specified page doesn't
1552 	 * exist.
1553 	 */
1554 	VM_OBJECT_ASSERT_WLOCKED(object);
1555 	if (__predict_true(vm_object_cache_is_empty(object)))
1556 		return (FALSE);
1557 	mtx_lock(&vm_page_queue_free_mtx);
1558 	m = vm_page_cache_lookup(object, pindex);
1559 	mtx_unlock(&vm_page_queue_free_mtx);
1560 	return (m != NULL);
1561 }
1562 
1563 /*
1564  *	vm_page_alloc:
1565  *
1566  *	Allocate and return a page that is associated with the specified
1567  *	object and offset pair.  By default, this page is exclusive busied.
1568  *
1569  *	The caller must always specify an allocation class.
1570  *
1571  *	allocation classes:
1572  *	VM_ALLOC_NORMAL		normal process request
1573  *	VM_ALLOC_SYSTEM		system *really* needs a page
1574  *	VM_ALLOC_INTERRUPT	interrupt time request
1575  *
1576  *	optional allocation flags:
1577  *	VM_ALLOC_COUNT(number)	the number of additional pages that the caller
1578  *				intends to allocate
1579  *	VM_ALLOC_IFCACHED	return page only if it is cached
1580  *	VM_ALLOC_IFNOTCACHED	return NULL, do not reactivate if the page
1581  *				is cached
1582  *	VM_ALLOC_NOBUSY		do not exclusive busy the page
1583  *	VM_ALLOC_NODUMP		do not include the page in a kernel core dump
1584  *	VM_ALLOC_NOOBJ		page is not associated with an object and
1585  *				should not be exclusive busy
1586  *	VM_ALLOC_SBUSY		shared busy the allocated page
1587  *	VM_ALLOC_WIRED		wire the allocated page
1588  *	VM_ALLOC_ZERO		prefer a zeroed page
1589  *
1590  *	This routine may not sleep.
1591  */
1592 vm_page_t
1593 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req)
1594 {
1595 	struct vnode *vp = NULL;
1596 	vm_object_t m_object;
1597 	vm_page_t m, mpred;
1598 	int flags, req_class;
1599 
1600 	mpred = 0;	/* XXX: pacify gcc */
1601 	KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0) &&
1602 	    (object != NULL || (req & VM_ALLOC_SBUSY) == 0) &&
1603 	    ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) !=
1604 	    (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)),
1605 	    ("vm_page_alloc: inconsistent object(%p)/req(%x)", (void *)object,
1606 	    req));
1607 	if (object != NULL)
1608 		VM_OBJECT_ASSERT_WLOCKED(object);
1609 
1610 	req_class = req & VM_ALLOC_CLASS_MASK;
1611 
1612 	/*
1613 	 * The page daemon is allowed to dig deeper into the free page list.
1614 	 */
1615 	if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT)
1616 		req_class = VM_ALLOC_SYSTEM;
1617 
1618 	if (object != NULL) {
1619 		mpred = vm_radix_lookup_le(&object->rtree, pindex);
1620 		KASSERT(mpred == NULL || mpred->pindex != pindex,
1621 		   ("vm_page_alloc: pindex already allocated"));
1622 	}
1623 
1624 	/*
1625 	 * The page allocation request can came from consumers which already
1626 	 * hold the free page queue mutex, like vm_page_insert() in
1627 	 * vm_page_cache().
1628 	 */
1629 	mtx_lock_flags(&vm_page_queue_free_mtx, MTX_RECURSE);
1630 	if (vm_cnt.v_free_count + vm_cnt.v_cache_count > vm_cnt.v_free_reserved ||
1631 	    (req_class == VM_ALLOC_SYSTEM &&
1632 	    vm_cnt.v_free_count + vm_cnt.v_cache_count > vm_cnt.v_interrupt_free_min) ||
1633 	    (req_class == VM_ALLOC_INTERRUPT &&
1634 	    vm_cnt.v_free_count + vm_cnt.v_cache_count > 0)) {
1635 		/*
1636 		 * Allocate from the free queue if the number of free pages
1637 		 * exceeds the minimum for the request class.
1638 		 */
1639 		if (object != NULL &&
1640 		    (m = vm_page_cache_lookup(object, pindex)) != NULL) {
1641 			if ((req & VM_ALLOC_IFNOTCACHED) != 0) {
1642 				mtx_unlock(&vm_page_queue_free_mtx);
1643 				return (NULL);
1644 			}
1645 			if (vm_phys_unfree_page(m))
1646 				vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m, 0);
1647 #if VM_NRESERVLEVEL > 0
1648 			else if (!vm_reserv_reactivate_page(m))
1649 #else
1650 			else
1651 #endif
1652 				panic("vm_page_alloc: cache page %p is missing"
1653 				    " from the free queue", m);
1654 		} else if ((req & VM_ALLOC_IFCACHED) != 0) {
1655 			mtx_unlock(&vm_page_queue_free_mtx);
1656 			return (NULL);
1657 #if VM_NRESERVLEVEL > 0
1658 		} else if (object == NULL || (object->flags & (OBJ_COLORED |
1659 		    OBJ_FICTITIOUS)) != OBJ_COLORED || (m =
1660 		    vm_reserv_alloc_page(object, pindex, mpred)) == NULL) {
1661 #else
1662 		} else {
1663 #endif
1664 			m = vm_phys_alloc_pages(object != NULL ?
1665 			    VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 0);
1666 #if VM_NRESERVLEVEL > 0
1667 			if (m == NULL && vm_reserv_reclaim_inactive()) {
1668 				m = vm_phys_alloc_pages(object != NULL ?
1669 				    VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT,
1670 				    0);
1671 			}
1672 #endif
1673 		}
1674 	} else {
1675 		/*
1676 		 * Not allocatable, give up.
1677 		 */
1678 		mtx_unlock(&vm_page_queue_free_mtx);
1679 		atomic_add_int(&vm_pageout_deficit,
1680 		    max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1));
1681 		pagedaemon_wakeup();
1682 		return (NULL);
1683 	}
1684 
1685 	/*
1686 	 *  At this point we had better have found a good page.
1687 	 */
1688 	KASSERT(m != NULL, ("vm_page_alloc: missing page"));
1689 	KASSERT(m->queue == PQ_NONE,
1690 	    ("vm_page_alloc: page %p has unexpected queue %d", m, m->queue));
1691 	KASSERT(m->wire_count == 0, ("vm_page_alloc: page %p is wired", m));
1692 	KASSERT(m->hold_count == 0, ("vm_page_alloc: page %p is held", m));
1693 	KASSERT(!vm_page_sbusied(m),
1694 	    ("vm_page_alloc: page %p is busy", m));
1695 	KASSERT(m->dirty == 0, ("vm_page_alloc: page %p is dirty", m));
1696 	KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT,
1697 	    ("vm_page_alloc: page %p has unexpected memattr %d", m,
1698 	    pmap_page_get_memattr(m)));
1699 	if ((m->flags & PG_CACHED) != 0) {
1700 		KASSERT((m->flags & PG_ZERO) == 0,
1701 		    ("vm_page_alloc: cached page %p is PG_ZERO", m));
1702 		KASSERT(m->valid != 0,
1703 		    ("vm_page_alloc: cached page %p is invalid", m));
1704 		if (m->object == object && m->pindex == pindex)
1705 			vm_cnt.v_reactivated++;
1706 		else
1707 			m->valid = 0;
1708 		m_object = m->object;
1709 		vm_page_cache_remove(m);
1710 		if (m_object->type == OBJT_VNODE &&
1711 		    vm_object_cache_is_empty(m_object))
1712 			vp = m_object->handle;
1713 	} else {
1714 		KASSERT(m->valid == 0,
1715 		    ("vm_page_alloc: free page %p is valid", m));
1716 		vm_phys_freecnt_adj(m, -1);
1717 		if ((m->flags & PG_ZERO) != 0)
1718 			vm_page_zero_count--;
1719 	}
1720 	mtx_unlock(&vm_page_queue_free_mtx);
1721 
1722 	/*
1723 	 * Initialize the page.  Only the PG_ZERO flag is inherited.
1724 	 */
1725 	flags = 0;
1726 	if ((req & VM_ALLOC_ZERO) != 0)
1727 		flags = PG_ZERO;
1728 	flags &= m->flags;
1729 	if ((req & VM_ALLOC_NODUMP) != 0)
1730 		flags |= PG_NODUMP;
1731 	m->flags = flags;
1732 	m->aflags = 0;
1733 	m->oflags = object == NULL || (object->flags & OBJ_UNMANAGED) != 0 ?
1734 	    VPO_UNMANAGED : 0;
1735 	m->busy_lock = VPB_UNBUSIED;
1736 	if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ | VM_ALLOC_SBUSY)) == 0)
1737 		m->busy_lock = VPB_SINGLE_EXCLUSIVER;
1738 	if ((req & VM_ALLOC_SBUSY) != 0)
1739 		m->busy_lock = VPB_SHARERS_WORD(1);
1740 	if (req & VM_ALLOC_WIRED) {
1741 		/*
1742 		 * The page lock is not required for wiring a page until that
1743 		 * page is inserted into the object.
1744 		 */
1745 		atomic_add_int(&vm_cnt.v_wire_count, 1);
1746 		m->wire_count = 1;
1747 	}
1748 	m->act_count = 0;
1749 
1750 	if (object != NULL) {
1751 		if (vm_page_insert_after(m, object, pindex, mpred)) {
1752 			/* See the comment below about hold count. */
1753 			if (vp != NULL)
1754 				vdrop(vp);
1755 			pagedaemon_wakeup();
1756 			if (req & VM_ALLOC_WIRED) {
1757 				atomic_subtract_int(&vm_cnt.v_wire_count, 1);
1758 				m->wire_count = 0;
1759 			}
1760 			m->object = NULL;
1761 			m->oflags = VPO_UNMANAGED;
1762 			vm_page_free(m);
1763 			return (NULL);
1764 		}
1765 
1766 		/* Ignore device objects; the pager sets "memattr" for them. */
1767 		if (object->memattr != VM_MEMATTR_DEFAULT &&
1768 		    (object->flags & OBJ_FICTITIOUS) == 0)
1769 			pmap_page_set_memattr(m, object->memattr);
1770 	} else
1771 		m->pindex = pindex;
1772 
1773 	/*
1774 	 * The following call to vdrop() must come after the above call
1775 	 * to vm_page_insert() in case both affect the same object and
1776 	 * vnode.  Otherwise, the affected vnode's hold count could
1777 	 * temporarily become zero.
1778 	 */
1779 	if (vp != NULL)
1780 		vdrop(vp);
1781 
1782 	/*
1783 	 * Don't wakeup too often - wakeup the pageout daemon when
1784 	 * we would be nearly out of memory.
1785 	 */
1786 	if (vm_paging_needed())
1787 		pagedaemon_wakeup();
1788 
1789 	return (m);
1790 }
1791 
1792 static void
1793 vm_page_alloc_contig_vdrop(struct spglist *lst)
1794 {
1795 
1796 	while (!SLIST_EMPTY(lst)) {
1797 		vdrop((struct vnode *)SLIST_FIRST(lst)-> plinks.s.pv);
1798 		SLIST_REMOVE_HEAD(lst, plinks.s.ss);
1799 	}
1800 }
1801 
1802 /*
1803  *	vm_page_alloc_contig:
1804  *
1805  *	Allocate a contiguous set of physical pages of the given size "npages"
1806  *	from the free lists.  All of the physical pages must be at or above
1807  *	the given physical address "low" and below the given physical address
1808  *	"high".  The given value "alignment" determines the alignment of the
1809  *	first physical page in the set.  If the given value "boundary" is
1810  *	non-zero, then the set of physical pages cannot cross any physical
1811  *	address boundary that is a multiple of that value.  Both "alignment"
1812  *	and "boundary" must be a power of two.
1813  *
1814  *	If the specified memory attribute, "memattr", is VM_MEMATTR_DEFAULT,
1815  *	then the memory attribute setting for the physical pages is configured
1816  *	to the object's memory attribute setting.  Otherwise, the memory
1817  *	attribute setting for the physical pages is configured to "memattr",
1818  *	overriding the object's memory attribute setting.  However, if the
1819  *	object's memory attribute setting is not VM_MEMATTR_DEFAULT, then the
1820  *	memory attribute setting for the physical pages cannot be configured
1821  *	to VM_MEMATTR_DEFAULT.
1822  *
1823  *	The caller must always specify an allocation class.
1824  *
1825  *	allocation classes:
1826  *	VM_ALLOC_NORMAL		normal process request
1827  *	VM_ALLOC_SYSTEM		system *really* needs a page
1828  *	VM_ALLOC_INTERRUPT	interrupt time request
1829  *
1830  *	optional allocation flags:
1831  *	VM_ALLOC_NOBUSY		do not exclusive busy the page
1832  *	VM_ALLOC_NODUMP		do not include the page in a kernel core dump
1833  *	VM_ALLOC_NOOBJ		page is not associated with an object and
1834  *				should not be exclusive busy
1835  *	VM_ALLOC_SBUSY		shared busy the allocated page
1836  *	VM_ALLOC_WIRED		wire the allocated page
1837  *	VM_ALLOC_ZERO		prefer a zeroed page
1838  *
1839  *	This routine may not sleep.
1840  */
1841 vm_page_t
1842 vm_page_alloc_contig(vm_object_t object, vm_pindex_t pindex, int req,
1843     u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment,
1844     vm_paddr_t boundary, vm_memattr_t memattr)
1845 {
1846 	struct vnode *drop;
1847 	struct spglist deferred_vdrop_list;
1848 	vm_page_t m, m_tmp, m_ret;
1849 	u_int flags;
1850 	int req_class;
1851 
1852 	KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0) &&
1853 	    (object != NULL || (req & VM_ALLOC_SBUSY) == 0) &&
1854 	    ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) !=
1855 	    (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)),
1856 	    ("vm_page_alloc: inconsistent object(%p)/req(%x)", (void *)object,
1857 	    req));
1858 	if (object != NULL) {
1859 		VM_OBJECT_ASSERT_WLOCKED(object);
1860 		KASSERT(object->type == OBJT_PHYS,
1861 		    ("vm_page_alloc_contig: object %p isn't OBJT_PHYS",
1862 		    object));
1863 	}
1864 	KASSERT(npages > 0, ("vm_page_alloc_contig: npages is zero"));
1865 	req_class = req & VM_ALLOC_CLASS_MASK;
1866 
1867 	/*
1868 	 * The page daemon is allowed to dig deeper into the free page list.
1869 	 */
1870 	if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT)
1871 		req_class = VM_ALLOC_SYSTEM;
1872 
1873 	SLIST_INIT(&deferred_vdrop_list);
1874 	mtx_lock(&vm_page_queue_free_mtx);
1875 	if (vm_cnt.v_free_count + vm_cnt.v_cache_count >= npages +
1876 	    vm_cnt.v_free_reserved || (req_class == VM_ALLOC_SYSTEM &&
1877 	    vm_cnt.v_free_count + vm_cnt.v_cache_count >= npages +
1878 	    vm_cnt.v_interrupt_free_min) || (req_class == VM_ALLOC_INTERRUPT &&
1879 	    vm_cnt.v_free_count + vm_cnt.v_cache_count >= npages)) {
1880 #if VM_NRESERVLEVEL > 0
1881 retry:
1882 		if (object == NULL || (object->flags & OBJ_COLORED) == 0 ||
1883 		    (m_ret = vm_reserv_alloc_contig(object, pindex, npages,
1884 		    low, high, alignment, boundary)) == NULL)
1885 #endif
1886 			m_ret = vm_phys_alloc_contig(npages, low, high,
1887 			    alignment, boundary);
1888 	} else {
1889 		mtx_unlock(&vm_page_queue_free_mtx);
1890 		atomic_add_int(&vm_pageout_deficit, npages);
1891 		pagedaemon_wakeup();
1892 		return (NULL);
1893 	}
1894 	if (m_ret != NULL)
1895 		for (m = m_ret; m < &m_ret[npages]; m++) {
1896 			drop = vm_page_alloc_init(m);
1897 			if (drop != NULL) {
1898 				/*
1899 				 * Enqueue the vnode for deferred vdrop().
1900 				 */
1901 				m->plinks.s.pv = drop;
1902 				SLIST_INSERT_HEAD(&deferred_vdrop_list, m,
1903 				    plinks.s.ss);
1904 			}
1905 		}
1906 	else {
1907 #if VM_NRESERVLEVEL > 0
1908 		if (vm_reserv_reclaim_contig(npages, low, high, alignment,
1909 		    boundary))
1910 			goto retry;
1911 #endif
1912 	}
1913 	mtx_unlock(&vm_page_queue_free_mtx);
1914 	if (m_ret == NULL)
1915 		return (NULL);
1916 
1917 	/*
1918 	 * Initialize the pages.  Only the PG_ZERO flag is inherited.
1919 	 */
1920 	flags = 0;
1921 	if ((req & VM_ALLOC_ZERO) != 0)
1922 		flags = PG_ZERO;
1923 	if ((req & VM_ALLOC_NODUMP) != 0)
1924 		flags |= PG_NODUMP;
1925 	if ((req & VM_ALLOC_WIRED) != 0)
1926 		atomic_add_int(&vm_cnt.v_wire_count, npages);
1927 	if (object != NULL) {
1928 		if (object->memattr != VM_MEMATTR_DEFAULT &&
1929 		    memattr == VM_MEMATTR_DEFAULT)
1930 			memattr = object->memattr;
1931 	}
1932 	for (m = m_ret; m < &m_ret[npages]; m++) {
1933 		m->aflags = 0;
1934 		m->flags = (m->flags | PG_NODUMP) & flags;
1935 		m->busy_lock = VPB_UNBUSIED;
1936 		if (object != NULL) {
1937 			if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) == 0)
1938 				m->busy_lock = VPB_SINGLE_EXCLUSIVER;
1939 			if ((req & VM_ALLOC_SBUSY) != 0)
1940 				m->busy_lock = VPB_SHARERS_WORD(1);
1941 		}
1942 		if ((req & VM_ALLOC_WIRED) != 0)
1943 			m->wire_count = 1;
1944 		/* Unmanaged pages don't use "act_count". */
1945 		m->oflags = VPO_UNMANAGED;
1946 		if (object != NULL) {
1947 			if (vm_page_insert(m, object, pindex)) {
1948 				vm_page_alloc_contig_vdrop(
1949 				    &deferred_vdrop_list);
1950 				if (vm_paging_needed())
1951 					pagedaemon_wakeup();
1952 				if ((req & VM_ALLOC_WIRED) != 0)
1953 					atomic_subtract_int(&vm_cnt.v_wire_count,
1954 					    npages);
1955 				for (m_tmp = m, m = m_ret;
1956 				    m < &m_ret[npages]; m++) {
1957 					if ((req & VM_ALLOC_WIRED) != 0)
1958 						m->wire_count = 0;
1959 					if (m >= m_tmp)
1960 						m->object = NULL;
1961 					vm_page_free(m);
1962 				}
1963 				return (NULL);
1964 			}
1965 		} else
1966 			m->pindex = pindex;
1967 		if (memattr != VM_MEMATTR_DEFAULT)
1968 			pmap_page_set_memattr(m, memattr);
1969 		pindex++;
1970 	}
1971 	vm_page_alloc_contig_vdrop(&deferred_vdrop_list);
1972 	if (vm_paging_needed())
1973 		pagedaemon_wakeup();
1974 	return (m_ret);
1975 }
1976 
1977 /*
1978  * Initialize a page that has been freshly dequeued from a freelist.
1979  * The caller has to drop the vnode returned, if it is not NULL.
1980  *
1981  * This function may only be used to initialize unmanaged pages.
1982  *
1983  * To be called with vm_page_queue_free_mtx held.
1984  */
1985 static struct vnode *
1986 vm_page_alloc_init(vm_page_t m)
1987 {
1988 	struct vnode *drop;
1989 	vm_object_t m_object;
1990 
1991 	KASSERT(m->queue == PQ_NONE,
1992 	    ("vm_page_alloc_init: page %p has unexpected queue %d",
1993 	    m, m->queue));
1994 	KASSERT(m->wire_count == 0,
1995 	    ("vm_page_alloc_init: page %p is wired", m));
1996 	KASSERT(m->hold_count == 0,
1997 	    ("vm_page_alloc_init: page %p is held", m));
1998 	KASSERT(!vm_page_sbusied(m),
1999 	    ("vm_page_alloc_init: page %p is busy", m));
2000 	KASSERT(m->dirty == 0,
2001 	    ("vm_page_alloc_init: page %p is dirty", m));
2002 	KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT,
2003 	    ("vm_page_alloc_init: page %p has unexpected memattr %d",
2004 	    m, pmap_page_get_memattr(m)));
2005 	mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
2006 	drop = NULL;
2007 	if ((m->flags & PG_CACHED) != 0) {
2008 		KASSERT((m->flags & PG_ZERO) == 0,
2009 		    ("vm_page_alloc_init: cached page %p is PG_ZERO", m));
2010 		m->valid = 0;
2011 		m_object = m->object;
2012 		vm_page_cache_remove(m);
2013 		if (m_object->type == OBJT_VNODE &&
2014 		    vm_object_cache_is_empty(m_object))
2015 			drop = m_object->handle;
2016 	} else {
2017 		KASSERT(m->valid == 0,
2018 		    ("vm_page_alloc_init: free page %p is valid", m));
2019 		vm_phys_freecnt_adj(m, -1);
2020 		if ((m->flags & PG_ZERO) != 0)
2021 			vm_page_zero_count--;
2022 	}
2023 	return (drop);
2024 }
2025 
2026 /*
2027  * 	vm_page_alloc_freelist:
2028  *
2029  *	Allocate a physical page from the specified free page list.
2030  *
2031  *	The caller must always specify an allocation class.
2032  *
2033  *	allocation classes:
2034  *	VM_ALLOC_NORMAL		normal process request
2035  *	VM_ALLOC_SYSTEM		system *really* needs a page
2036  *	VM_ALLOC_INTERRUPT	interrupt time request
2037  *
2038  *	optional allocation flags:
2039  *	VM_ALLOC_COUNT(number)	the number of additional pages that the caller
2040  *				intends to allocate
2041  *	VM_ALLOC_WIRED		wire the allocated page
2042  *	VM_ALLOC_ZERO		prefer a zeroed page
2043  *
2044  *	This routine may not sleep.
2045  */
2046 vm_page_t
2047 vm_page_alloc_freelist(int flind, int req)
2048 {
2049 	struct vnode *drop;
2050 	vm_page_t m;
2051 	u_int flags;
2052 	int req_class;
2053 
2054 	req_class = req & VM_ALLOC_CLASS_MASK;
2055 
2056 	/*
2057 	 * The page daemon is allowed to dig deeper into the free page list.
2058 	 */
2059 	if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT)
2060 		req_class = VM_ALLOC_SYSTEM;
2061 
2062 	/*
2063 	 * Do not allocate reserved pages unless the req has asked for it.
2064 	 */
2065 	mtx_lock_flags(&vm_page_queue_free_mtx, MTX_RECURSE);
2066 	if (vm_cnt.v_free_count + vm_cnt.v_cache_count > vm_cnt.v_free_reserved ||
2067 	    (req_class == VM_ALLOC_SYSTEM &&
2068 	    vm_cnt.v_free_count + vm_cnt.v_cache_count > vm_cnt.v_interrupt_free_min) ||
2069 	    (req_class == VM_ALLOC_INTERRUPT &&
2070 	    vm_cnt.v_free_count + vm_cnt.v_cache_count > 0))
2071 		m = vm_phys_alloc_freelist_pages(flind, VM_FREEPOOL_DIRECT, 0);
2072 	else {
2073 		mtx_unlock(&vm_page_queue_free_mtx);
2074 		atomic_add_int(&vm_pageout_deficit,
2075 		    max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1));
2076 		pagedaemon_wakeup();
2077 		return (NULL);
2078 	}
2079 	if (m == NULL) {
2080 		mtx_unlock(&vm_page_queue_free_mtx);
2081 		return (NULL);
2082 	}
2083 	drop = vm_page_alloc_init(m);
2084 	mtx_unlock(&vm_page_queue_free_mtx);
2085 
2086 	/*
2087 	 * Initialize the page.  Only the PG_ZERO flag is inherited.
2088 	 */
2089 	m->aflags = 0;
2090 	flags = 0;
2091 	if ((req & VM_ALLOC_ZERO) != 0)
2092 		flags = PG_ZERO;
2093 	m->flags &= flags;
2094 	if ((req & VM_ALLOC_WIRED) != 0) {
2095 		/*
2096 		 * The page lock is not required for wiring a page that does
2097 		 * not belong to an object.
2098 		 */
2099 		atomic_add_int(&vm_cnt.v_wire_count, 1);
2100 		m->wire_count = 1;
2101 	}
2102 	/* Unmanaged pages don't use "act_count". */
2103 	m->oflags = VPO_UNMANAGED;
2104 	if (drop != NULL)
2105 		vdrop(drop);
2106 	if (vm_paging_needed())
2107 		pagedaemon_wakeup();
2108 	return (m);
2109 }
2110 
2111 /*
2112  *	vm_wait:	(also see VM_WAIT macro)
2113  *
2114  *	Sleep until free pages are available for allocation.
2115  *	- Called in various places before memory allocations.
2116  */
2117 void
2118 vm_wait(void)
2119 {
2120 
2121 	mtx_lock(&vm_page_queue_free_mtx);
2122 	if (curproc == pageproc) {
2123 		vm_pageout_pages_needed = 1;
2124 		msleep(&vm_pageout_pages_needed, &vm_page_queue_free_mtx,
2125 		    PDROP | PSWP, "VMWait", 0);
2126 	} else {
2127 		if (!vm_pages_needed) {
2128 			vm_pages_needed = 1;
2129 			wakeup(&vm_pages_needed);
2130 		}
2131 		msleep(&vm_cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PVM,
2132 		    "vmwait", 0);
2133 	}
2134 }
2135 
2136 /*
2137  *	vm_waitpfault:	(also see VM_WAITPFAULT macro)
2138  *
2139  *	Sleep until free pages are available for allocation.
2140  *	- Called only in vm_fault so that processes page faulting
2141  *	  can be easily tracked.
2142  *	- Sleeps at a lower priority than vm_wait() so that vm_wait()ing
2143  *	  processes will be able to grab memory first.  Do not change
2144  *	  this balance without careful testing first.
2145  */
2146 void
2147 vm_waitpfault(void)
2148 {
2149 
2150 	mtx_lock(&vm_page_queue_free_mtx);
2151 	if (!vm_pages_needed) {
2152 		vm_pages_needed = 1;
2153 		wakeup(&vm_pages_needed);
2154 	}
2155 	msleep(&vm_cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PUSER,
2156 	    "pfault", 0);
2157 }
2158 
2159 struct vm_pagequeue *
2160 vm_page_pagequeue(vm_page_t m)
2161 {
2162 
2163 	return (&vm_phys_domain(m)->vmd_pagequeues[m->queue]);
2164 }
2165 
2166 /*
2167  *	vm_page_dequeue:
2168  *
2169  *	Remove the given page from its current page queue.
2170  *
2171  *	The page must be locked.
2172  */
2173 void
2174 vm_page_dequeue(vm_page_t m)
2175 {
2176 	struct vm_pagequeue *pq;
2177 
2178 	vm_page_assert_locked(m);
2179 	KASSERT(m->queue < PQ_COUNT, ("vm_page_dequeue: page %p is not queued",
2180 	    m));
2181 	pq = vm_page_pagequeue(m);
2182 	vm_pagequeue_lock(pq);
2183 	m->queue = PQ_NONE;
2184 	TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
2185 	vm_pagequeue_cnt_dec(pq);
2186 	vm_pagequeue_unlock(pq);
2187 }
2188 
2189 /*
2190  *	vm_page_dequeue_locked:
2191  *
2192  *	Remove the given page from its current page queue.
2193  *
2194  *	The page and page queue must be locked.
2195  */
2196 void
2197 vm_page_dequeue_locked(vm_page_t m)
2198 {
2199 	struct vm_pagequeue *pq;
2200 
2201 	vm_page_lock_assert(m, MA_OWNED);
2202 	pq = vm_page_pagequeue(m);
2203 	vm_pagequeue_assert_locked(pq);
2204 	m->queue = PQ_NONE;
2205 	TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
2206 	vm_pagequeue_cnt_dec(pq);
2207 }
2208 
2209 /*
2210  *	vm_page_enqueue:
2211  *
2212  *	Add the given page to the specified page queue.
2213  *
2214  *	The page must be locked.
2215  */
2216 static void
2217 vm_page_enqueue(uint8_t queue, vm_page_t m)
2218 {
2219 	struct vm_pagequeue *pq;
2220 
2221 	vm_page_lock_assert(m, MA_OWNED);
2222 	KASSERT(queue < PQ_COUNT,
2223 	    ("vm_page_enqueue: invalid queue %u request for page %p",
2224 	    queue, m));
2225 	pq = &vm_phys_domain(m)->vmd_pagequeues[queue];
2226 	vm_pagequeue_lock(pq);
2227 	m->queue = queue;
2228 	TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
2229 	vm_pagequeue_cnt_inc(pq);
2230 	vm_pagequeue_unlock(pq);
2231 }
2232 
2233 /*
2234  *	vm_page_requeue:
2235  *
2236  *	Move the given page to the tail of its current page queue.
2237  *
2238  *	The page must be locked.
2239  */
2240 void
2241 vm_page_requeue(vm_page_t m)
2242 {
2243 	struct vm_pagequeue *pq;
2244 
2245 	vm_page_lock_assert(m, MA_OWNED);
2246 	KASSERT(m->queue != PQ_NONE,
2247 	    ("vm_page_requeue: page %p is not queued", m));
2248 	pq = vm_page_pagequeue(m);
2249 	vm_pagequeue_lock(pq);
2250 	TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
2251 	TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
2252 	vm_pagequeue_unlock(pq);
2253 }
2254 
2255 /*
2256  *	vm_page_requeue_locked:
2257  *
2258  *	Move the given page to the tail of its current page queue.
2259  *
2260  *	The page queue must be locked.
2261  */
2262 void
2263 vm_page_requeue_locked(vm_page_t m)
2264 {
2265 	struct vm_pagequeue *pq;
2266 
2267 	KASSERT(m->queue != PQ_NONE,
2268 	    ("vm_page_requeue_locked: page %p is not queued", m));
2269 	pq = vm_page_pagequeue(m);
2270 	vm_pagequeue_assert_locked(pq);
2271 	TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
2272 	TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
2273 }
2274 
2275 /*
2276  *	vm_page_activate:
2277  *
2278  *	Put the specified page on the active list (if appropriate).
2279  *	Ensure that act_count is at least ACT_INIT but do not otherwise
2280  *	mess with it.
2281  *
2282  *	The page must be locked.
2283  */
2284 void
2285 vm_page_activate(vm_page_t m)
2286 {
2287 	int queue;
2288 
2289 	vm_page_lock_assert(m, MA_OWNED);
2290 	if ((queue = m->queue) != PQ_ACTIVE) {
2291 		if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) {
2292 			if (m->act_count < ACT_INIT)
2293 				m->act_count = ACT_INIT;
2294 			if (queue != PQ_NONE)
2295 				vm_page_dequeue(m);
2296 			vm_page_enqueue(PQ_ACTIVE, m);
2297 		} else
2298 			KASSERT(queue == PQ_NONE,
2299 			    ("vm_page_activate: wired page %p is queued", m));
2300 	} else {
2301 		if (m->act_count < ACT_INIT)
2302 			m->act_count = ACT_INIT;
2303 	}
2304 }
2305 
2306 /*
2307  *	vm_page_free_wakeup:
2308  *
2309  *	Helper routine for vm_page_free_toq() and vm_page_cache().  This
2310  *	routine is called when a page has been added to the cache or free
2311  *	queues.
2312  *
2313  *	The page queues must be locked.
2314  */
2315 static inline void
2316 vm_page_free_wakeup(void)
2317 {
2318 
2319 	mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
2320 	/*
2321 	 * if pageout daemon needs pages, then tell it that there are
2322 	 * some free.
2323 	 */
2324 	if (vm_pageout_pages_needed &&
2325 	    vm_cnt.v_cache_count + vm_cnt.v_free_count >= vm_cnt.v_pageout_free_min) {
2326 		wakeup(&vm_pageout_pages_needed);
2327 		vm_pageout_pages_needed = 0;
2328 	}
2329 	/*
2330 	 * wakeup processes that are waiting on memory if we hit a
2331 	 * high water mark. And wakeup scheduler process if we have
2332 	 * lots of memory. this process will swapin processes.
2333 	 */
2334 	if (vm_pages_needed && !vm_page_count_min()) {
2335 		vm_pages_needed = 0;
2336 		wakeup(&vm_cnt.v_free_count);
2337 	}
2338 }
2339 
2340 /*
2341  *	Turn a cached page into a free page, by changing its attributes.
2342  *	Keep the statistics up-to-date.
2343  *
2344  *	The free page queue must be locked.
2345  */
2346 static void
2347 vm_page_cache_turn_free(vm_page_t m)
2348 {
2349 
2350 	mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
2351 
2352 	m->object = NULL;
2353 	m->valid = 0;
2354 	KASSERT((m->flags & PG_CACHED) != 0,
2355 	    ("vm_page_cache_turn_free: page %p is not cached", m));
2356 	m->flags &= ~PG_CACHED;
2357 	vm_cnt.v_cache_count--;
2358 	vm_phys_freecnt_adj(m, 1);
2359 }
2360 
2361 /*
2362  *	vm_page_free_toq:
2363  *
2364  *	Returns the given page to the free list,
2365  *	disassociating it with any VM object.
2366  *
2367  *	The object must be locked.  The page must be locked if it is managed.
2368  */
2369 void
2370 vm_page_free_toq(vm_page_t m)
2371 {
2372 
2373 	if ((m->oflags & VPO_UNMANAGED) == 0) {
2374 		vm_page_lock_assert(m, MA_OWNED);
2375 		KASSERT(!pmap_page_is_mapped(m),
2376 		    ("vm_page_free_toq: freeing mapped page %p", m));
2377 	} else
2378 		KASSERT(m->queue == PQ_NONE,
2379 		    ("vm_page_free_toq: unmanaged page %p is queued", m));
2380 	PCPU_INC(cnt.v_tfree);
2381 
2382 	if (vm_page_sbusied(m))
2383 		panic("vm_page_free: freeing busy page %p", m);
2384 
2385 	/*
2386 	 * Unqueue, then remove page.  Note that we cannot destroy
2387 	 * the page here because we do not want to call the pager's
2388 	 * callback routine until after we've put the page on the
2389 	 * appropriate free queue.
2390 	 */
2391 	vm_page_remque(m);
2392 	vm_page_remove(m);
2393 
2394 	/*
2395 	 * If fictitious remove object association and
2396 	 * return, otherwise delay object association removal.
2397 	 */
2398 	if ((m->flags & PG_FICTITIOUS) != 0) {
2399 		return;
2400 	}
2401 
2402 	m->valid = 0;
2403 	vm_page_undirty(m);
2404 
2405 	if (m->wire_count != 0)
2406 		panic("vm_page_free: freeing wired page %p", m);
2407 	if (m->hold_count != 0) {
2408 		m->flags &= ~PG_ZERO;
2409 		KASSERT((m->flags & PG_UNHOLDFREE) == 0,
2410 		    ("vm_page_free: freeing PG_UNHOLDFREE page %p", m));
2411 		m->flags |= PG_UNHOLDFREE;
2412 	} else {
2413 		/*
2414 		 * Restore the default memory attribute to the page.
2415 		 */
2416 		if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT)
2417 			pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT);
2418 
2419 		/*
2420 		 * Insert the page into the physical memory allocator's
2421 		 * cache/free page queues.
2422 		 */
2423 		mtx_lock(&vm_page_queue_free_mtx);
2424 		vm_phys_freecnt_adj(m, 1);
2425 #if VM_NRESERVLEVEL > 0
2426 		if (!vm_reserv_free_page(m))
2427 #else
2428 		if (TRUE)
2429 #endif
2430 			vm_phys_free_pages(m, 0);
2431 		if ((m->flags & PG_ZERO) != 0)
2432 			++vm_page_zero_count;
2433 		else
2434 			vm_page_zero_idle_wakeup();
2435 		vm_page_free_wakeup();
2436 		mtx_unlock(&vm_page_queue_free_mtx);
2437 	}
2438 }
2439 
2440 /*
2441  *	vm_page_wire:
2442  *
2443  *	Mark this page as wired down by yet
2444  *	another map, removing it from paging queues
2445  *	as necessary.
2446  *
2447  *	If the page is fictitious, then its wire count must remain one.
2448  *
2449  *	The page must be locked.
2450  */
2451 void
2452 vm_page_wire(vm_page_t m)
2453 {
2454 
2455 	/*
2456 	 * Only bump the wire statistics if the page is not already wired,
2457 	 * and only unqueue the page if it is on some queue (if it is unmanaged
2458 	 * it is already off the queues).
2459 	 */
2460 	vm_page_lock_assert(m, MA_OWNED);
2461 	if ((m->flags & PG_FICTITIOUS) != 0) {
2462 		KASSERT(m->wire_count == 1,
2463 		    ("vm_page_wire: fictitious page %p's wire count isn't one",
2464 		    m));
2465 		return;
2466 	}
2467 	if (m->wire_count == 0) {
2468 		KASSERT((m->oflags & VPO_UNMANAGED) == 0 ||
2469 		    m->queue == PQ_NONE,
2470 		    ("vm_page_wire: unmanaged page %p is queued", m));
2471 		vm_page_remque(m);
2472 		atomic_add_int(&vm_cnt.v_wire_count, 1);
2473 	}
2474 	m->wire_count++;
2475 	KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m));
2476 }
2477 
2478 /*
2479  * vm_page_unwire:
2480  *
2481  * Release one wiring of the specified page, potentially allowing it to be
2482  * paged out.  Returns TRUE if the number of wirings transitions to zero and
2483  * FALSE otherwise.
2484  *
2485  * Only managed pages belonging to an object can be paged out.  If the number
2486  * of wirings transitions to zero and the page is eligible for page out, then
2487  * the page is added to the specified paging queue (unless PQ_NONE is
2488  * specified).
2489  *
2490  * If a page is fictitious, then its wire count must always be one.
2491  *
2492  * A managed page must be locked.
2493  */
2494 boolean_t
2495 vm_page_unwire(vm_page_t m, uint8_t queue)
2496 {
2497 
2498 	KASSERT(queue < PQ_COUNT || queue == PQ_NONE,
2499 	    ("vm_page_unwire: invalid queue %u request for page %p",
2500 	    queue, m));
2501 	if ((m->oflags & VPO_UNMANAGED) == 0)
2502 		vm_page_assert_locked(m);
2503 	if ((m->flags & PG_FICTITIOUS) != 0) {
2504 		KASSERT(m->wire_count == 1,
2505 	    ("vm_page_unwire: fictitious page %p's wire count isn't one", m));
2506 		return (FALSE);
2507 	}
2508 	if (m->wire_count > 0) {
2509 		m->wire_count--;
2510 		if (m->wire_count == 0) {
2511 			atomic_subtract_int(&vm_cnt.v_wire_count, 1);
2512 			if ((m->oflags & VPO_UNMANAGED) == 0 &&
2513 			    m->object != NULL && queue != PQ_NONE) {
2514 				if (queue == PQ_INACTIVE)
2515 					m->flags &= ~PG_WINATCFLS;
2516 				vm_page_enqueue(queue, m);
2517 			}
2518 			return (TRUE);
2519 		} else
2520 			return (FALSE);
2521 	} else
2522 		panic("vm_page_unwire: page %p's wire count is zero", m);
2523 }
2524 
2525 /*
2526  * Move the specified page to the inactive queue.
2527  *
2528  * Many pages placed on the inactive queue should actually go
2529  * into the cache, but it is difficult to figure out which.  What
2530  * we do instead, if the inactive target is well met, is to put
2531  * clean pages at the head of the inactive queue instead of the tail.
2532  * This will cause them to be moved to the cache more quickly and
2533  * if not actively re-referenced, reclaimed more quickly.  If we just
2534  * stick these pages at the end of the inactive queue, heavy filesystem
2535  * meta-data accesses can cause an unnecessary paging load on memory bound
2536  * processes.  This optimization causes one-time-use metadata to be
2537  * reused more quickly.
2538  *
2539  * Normally noreuse is FALSE, resulting in LRU operation.  noreuse is set
2540  * to TRUE if we want this page to be 'as if it were placed in the cache',
2541  * except without unmapping it from the process address space.  In
2542  * practice this is implemented by inserting the page at the head of the
2543  * queue, using a marker page to guide FIFO insertion ordering.
2544  *
2545  * The page must be locked.
2546  */
2547 static inline void
2548 _vm_page_deactivate(vm_page_t m, boolean_t noreuse)
2549 {
2550 	struct vm_pagequeue *pq;
2551 	int queue;
2552 
2553 	vm_page_assert_locked(m);
2554 
2555 	/*
2556 	 * Ignore if the page is already inactive, unless it is unlikely to be
2557 	 * reactivated.
2558 	 */
2559 	if ((queue = m->queue) == PQ_INACTIVE && !noreuse)
2560 		return;
2561 	if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) {
2562 		pq = &vm_phys_domain(m)->vmd_pagequeues[PQ_INACTIVE];
2563 		/* Avoid multiple acquisitions of the inactive queue lock. */
2564 		if (queue == PQ_INACTIVE) {
2565 			vm_pagequeue_lock(pq);
2566 			vm_page_dequeue_locked(m);
2567 		} else {
2568 			if (queue != PQ_NONE)
2569 				vm_page_dequeue(m);
2570 			m->flags &= ~PG_WINATCFLS;
2571 			vm_pagequeue_lock(pq);
2572 		}
2573 		m->queue = PQ_INACTIVE;
2574 		if (noreuse)
2575 			TAILQ_INSERT_BEFORE(&vm_phys_domain(m)->vmd_inacthead,
2576 			    m, plinks.q);
2577 		else
2578 			TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
2579 		vm_pagequeue_cnt_inc(pq);
2580 		vm_pagequeue_unlock(pq);
2581 	}
2582 }
2583 
2584 /*
2585  * Move the specified page to the inactive queue.
2586  *
2587  * The page must be locked.
2588  */
2589 void
2590 vm_page_deactivate(vm_page_t m)
2591 {
2592 
2593 	_vm_page_deactivate(m, FALSE);
2594 }
2595 
2596 /*
2597  * Move the specified page to the inactive queue with the expectation
2598  * that it is unlikely to be reused.
2599  *
2600  * The page must be locked.
2601  */
2602 void
2603 vm_page_deactivate_noreuse(vm_page_t m)
2604 {
2605 
2606 	_vm_page_deactivate(m, TRUE);
2607 }
2608 
2609 /*
2610  * vm_page_try_to_cache:
2611  *
2612  * Returns 0 on failure, 1 on success
2613  */
2614 int
2615 vm_page_try_to_cache(vm_page_t m)
2616 {
2617 
2618 	vm_page_lock_assert(m, MA_OWNED);
2619 	VM_OBJECT_ASSERT_WLOCKED(m->object);
2620 	if (m->dirty || m->hold_count || m->wire_count ||
2621 	    (m->oflags & VPO_UNMANAGED) != 0 || vm_page_busied(m))
2622 		return (0);
2623 	pmap_remove_all(m);
2624 	if (m->dirty)
2625 		return (0);
2626 	vm_page_cache(m);
2627 	return (1);
2628 }
2629 
2630 /*
2631  * vm_page_try_to_free()
2632  *
2633  *	Attempt to free the page.  If we cannot free it, we do nothing.
2634  *	1 is returned on success, 0 on failure.
2635  */
2636 int
2637 vm_page_try_to_free(vm_page_t m)
2638 {
2639 
2640 	vm_page_lock_assert(m, MA_OWNED);
2641 	if (m->object != NULL)
2642 		VM_OBJECT_ASSERT_WLOCKED(m->object);
2643 	if (m->dirty || m->hold_count || m->wire_count ||
2644 	    (m->oflags & VPO_UNMANAGED) != 0 || vm_page_busied(m))
2645 		return (0);
2646 	pmap_remove_all(m);
2647 	if (m->dirty)
2648 		return (0);
2649 	vm_page_free(m);
2650 	return (1);
2651 }
2652 
2653 /*
2654  * vm_page_cache
2655  *
2656  * Put the specified page onto the page cache queue (if appropriate).
2657  *
2658  * The object and page must be locked.
2659  */
2660 void
2661 vm_page_cache(vm_page_t m)
2662 {
2663 	vm_object_t object;
2664 	boolean_t cache_was_empty;
2665 
2666 	vm_page_lock_assert(m, MA_OWNED);
2667 	object = m->object;
2668 	VM_OBJECT_ASSERT_WLOCKED(object);
2669 	if (vm_page_busied(m) || (m->oflags & VPO_UNMANAGED) ||
2670 	    m->hold_count || m->wire_count)
2671 		panic("vm_page_cache: attempting to cache busy page");
2672 	KASSERT(!pmap_page_is_mapped(m),
2673 	    ("vm_page_cache: page %p is mapped", m));
2674 	KASSERT(m->dirty == 0, ("vm_page_cache: page %p is dirty", m));
2675 	if (m->valid == 0 || object->type == OBJT_DEFAULT ||
2676 	    (object->type == OBJT_SWAP &&
2677 	    !vm_pager_has_page(object, m->pindex, NULL, NULL))) {
2678 		/*
2679 		 * Hypothesis: A cache-eligible page belonging to a
2680 		 * default object or swap object but without a backing
2681 		 * store must be zero filled.
2682 		 */
2683 		vm_page_free(m);
2684 		return;
2685 	}
2686 	KASSERT((m->flags & PG_CACHED) == 0,
2687 	    ("vm_page_cache: page %p is already cached", m));
2688 
2689 	/*
2690 	 * Remove the page from the paging queues.
2691 	 */
2692 	vm_page_remque(m);
2693 
2694 	/*
2695 	 * Remove the page from the object's collection of resident
2696 	 * pages.
2697 	 */
2698 	vm_radix_remove(&object->rtree, m->pindex);
2699 	TAILQ_REMOVE(&object->memq, m, listq);
2700 	object->resident_page_count--;
2701 
2702 	/*
2703 	 * Restore the default memory attribute to the page.
2704 	 */
2705 	if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT)
2706 		pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT);
2707 
2708 	/*
2709 	 * Insert the page into the object's collection of cached pages
2710 	 * and the physical memory allocator's cache/free page queues.
2711 	 */
2712 	m->flags &= ~PG_ZERO;
2713 	mtx_lock(&vm_page_queue_free_mtx);
2714 	cache_was_empty = vm_radix_is_empty(&object->cache);
2715 	if (vm_radix_insert(&object->cache, m)) {
2716 		mtx_unlock(&vm_page_queue_free_mtx);
2717 		if (object->resident_page_count == 0)
2718 			vdrop(object->handle);
2719 		m->object = NULL;
2720 		vm_page_free(m);
2721 		return;
2722 	}
2723 
2724 	/*
2725 	 * The above call to vm_radix_insert() could reclaim the one pre-
2726 	 * existing cached page from this object, resulting in a call to
2727 	 * vdrop().
2728 	 */
2729 	if (!cache_was_empty)
2730 		cache_was_empty = vm_radix_is_singleton(&object->cache);
2731 
2732 	m->flags |= PG_CACHED;
2733 	vm_cnt.v_cache_count++;
2734 	PCPU_INC(cnt.v_tcached);
2735 #if VM_NRESERVLEVEL > 0
2736 	if (!vm_reserv_free_page(m)) {
2737 #else
2738 	if (TRUE) {
2739 #endif
2740 		vm_phys_free_pages(m, 0);
2741 	}
2742 	vm_page_free_wakeup();
2743 	mtx_unlock(&vm_page_queue_free_mtx);
2744 
2745 	/*
2746 	 * Increment the vnode's hold count if this is the object's only
2747 	 * cached page.  Decrement the vnode's hold count if this was
2748 	 * the object's only resident page.
2749 	 */
2750 	if (object->type == OBJT_VNODE) {
2751 		if (cache_was_empty && object->resident_page_count != 0)
2752 			vhold(object->handle);
2753 		else if (!cache_was_empty && object->resident_page_count == 0)
2754 			vdrop(object->handle);
2755 	}
2756 }
2757 
2758 /*
2759  * vm_page_advise
2760  *
2761  * 	Deactivate or do nothing, as appropriate.
2762  *
2763  *	The object and page must be locked.
2764  */
2765 void
2766 vm_page_advise(vm_page_t m, int advice)
2767 {
2768 
2769 	vm_page_assert_locked(m);
2770 	VM_OBJECT_ASSERT_WLOCKED(m->object);
2771 	if (advice == MADV_FREE)
2772 		/*
2773 		 * Mark the page clean.  This will allow the page to be freed
2774 		 * up by the system.  However, such pages are often reused
2775 		 * quickly by malloc() so we do not do anything that would
2776 		 * cause a page fault if we can help it.
2777 		 *
2778 		 * Specifically, we do not try to actually free the page now
2779 		 * nor do we try to put it in the cache (which would cause a
2780 		 * page fault on reuse).
2781 		 *
2782 		 * But we do make the page as freeable as we can without
2783 		 * actually taking the step of unmapping it.
2784 		 */
2785 		m->dirty = 0;
2786 	else if (advice != MADV_DONTNEED)
2787 		return;
2788 
2789 	/*
2790 	 * Clear any references to the page.  Otherwise, the page daemon will
2791 	 * immediately reactivate the page.
2792 	 */
2793 	vm_page_aflag_clear(m, PGA_REFERENCED);
2794 
2795 	if (advice != MADV_FREE && m->dirty == 0 && pmap_is_modified(m))
2796 		vm_page_dirty(m);
2797 
2798 	/*
2799 	 * Place clean pages at the head of the inactive queue rather than the
2800 	 * tail, thus defeating the queue's LRU operation and ensuring that the
2801 	 * page will be reused quickly.
2802 	 */
2803 	_vm_page_deactivate(m, m->dirty == 0);
2804 }
2805 
2806 /*
2807  * Grab a page, waiting until we are waken up due to the page
2808  * changing state.  We keep on waiting, if the page continues
2809  * to be in the object.  If the page doesn't exist, first allocate it
2810  * and then conditionally zero it.
2811  *
2812  * This routine may sleep.
2813  *
2814  * The object must be locked on entry.  The lock will, however, be released
2815  * and reacquired if the routine sleeps.
2816  */
2817 vm_page_t
2818 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
2819 {
2820 	vm_page_t m;
2821 	int sleep;
2822 
2823 	VM_OBJECT_ASSERT_WLOCKED(object);
2824 	KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
2825 	    (allocflags & VM_ALLOC_IGN_SBUSY) != 0,
2826 	    ("vm_page_grab: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY mismatch"));
2827 retrylookup:
2828 	if ((m = vm_page_lookup(object, pindex)) != NULL) {
2829 		sleep = (allocflags & VM_ALLOC_IGN_SBUSY) != 0 ?
2830 		    vm_page_xbusied(m) : vm_page_busied(m);
2831 		if (sleep) {
2832 			if ((allocflags & VM_ALLOC_NOWAIT) != 0)
2833 				return (NULL);
2834 			/*
2835 			 * Reference the page before unlocking and
2836 			 * sleeping so that the page daemon is less
2837 			 * likely to reclaim it.
2838 			 */
2839 			vm_page_aflag_set(m, PGA_REFERENCED);
2840 			vm_page_lock(m);
2841 			VM_OBJECT_WUNLOCK(object);
2842 			vm_page_busy_sleep(m, "pgrbwt");
2843 			VM_OBJECT_WLOCK(object);
2844 			goto retrylookup;
2845 		} else {
2846 			if ((allocflags & VM_ALLOC_WIRED) != 0) {
2847 				vm_page_lock(m);
2848 				vm_page_wire(m);
2849 				vm_page_unlock(m);
2850 			}
2851 			if ((allocflags &
2852 			    (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) == 0)
2853 				vm_page_xbusy(m);
2854 			if ((allocflags & VM_ALLOC_SBUSY) != 0)
2855 				vm_page_sbusy(m);
2856 			return (m);
2857 		}
2858 	}
2859 	m = vm_page_alloc(object, pindex, allocflags);
2860 	if (m == NULL) {
2861 		if ((allocflags & VM_ALLOC_NOWAIT) != 0)
2862 			return (NULL);
2863 		VM_OBJECT_WUNLOCK(object);
2864 		VM_WAIT;
2865 		VM_OBJECT_WLOCK(object);
2866 		goto retrylookup;
2867 	} else if (m->valid != 0)
2868 		return (m);
2869 	if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0)
2870 		pmap_zero_page(m);
2871 	return (m);
2872 }
2873 
2874 /*
2875  * Mapping function for valid or dirty bits in a page.
2876  *
2877  * Inputs are required to range within a page.
2878  */
2879 vm_page_bits_t
2880 vm_page_bits(int base, int size)
2881 {
2882 	int first_bit;
2883 	int last_bit;
2884 
2885 	KASSERT(
2886 	    base + size <= PAGE_SIZE,
2887 	    ("vm_page_bits: illegal base/size %d/%d", base, size)
2888 	);
2889 
2890 	if (size == 0)		/* handle degenerate case */
2891 		return (0);
2892 
2893 	first_bit = base >> DEV_BSHIFT;
2894 	last_bit = (base + size - 1) >> DEV_BSHIFT;
2895 
2896 	return (((vm_page_bits_t)2 << last_bit) -
2897 	    ((vm_page_bits_t)1 << first_bit));
2898 }
2899 
2900 /*
2901  *	vm_page_set_valid_range:
2902  *
2903  *	Sets portions of a page valid.  The arguments are expected
2904  *	to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
2905  *	of any partial chunks touched by the range.  The invalid portion of
2906  *	such chunks will be zeroed.
2907  *
2908  *	(base + size) must be less then or equal to PAGE_SIZE.
2909  */
2910 void
2911 vm_page_set_valid_range(vm_page_t m, int base, int size)
2912 {
2913 	int endoff, frag;
2914 
2915 	VM_OBJECT_ASSERT_WLOCKED(m->object);
2916 	if (size == 0)	/* handle degenerate case */
2917 		return;
2918 
2919 	/*
2920 	 * If the base is not DEV_BSIZE aligned and the valid
2921 	 * bit is clear, we have to zero out a portion of the
2922 	 * first block.
2923 	 */
2924 	if ((frag = base & ~(DEV_BSIZE - 1)) != base &&
2925 	    (m->valid & (1 << (base >> DEV_BSHIFT))) == 0)
2926 		pmap_zero_page_area(m, frag, base - frag);
2927 
2928 	/*
2929 	 * If the ending offset is not DEV_BSIZE aligned and the
2930 	 * valid bit is clear, we have to zero out a portion of
2931 	 * the last block.
2932 	 */
2933 	endoff = base + size;
2934 	if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff &&
2935 	    (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0)
2936 		pmap_zero_page_area(m, endoff,
2937 		    DEV_BSIZE - (endoff & (DEV_BSIZE - 1)));
2938 
2939 	/*
2940 	 * Assert that no previously invalid block that is now being validated
2941 	 * is already dirty.
2942 	 */
2943 	KASSERT((~m->valid & vm_page_bits(base, size) & m->dirty) == 0,
2944 	    ("vm_page_set_valid_range: page %p is dirty", m));
2945 
2946 	/*
2947 	 * Set valid bits inclusive of any overlap.
2948 	 */
2949 	m->valid |= vm_page_bits(base, size);
2950 }
2951 
2952 /*
2953  * Clear the given bits from the specified page's dirty field.
2954  */
2955 static __inline void
2956 vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits)
2957 {
2958 	uintptr_t addr;
2959 #if PAGE_SIZE < 16384
2960 	int shift;
2961 #endif
2962 
2963 	/*
2964 	 * If the object is locked and the page is neither exclusive busy nor
2965 	 * write mapped, then the page's dirty field cannot possibly be
2966 	 * set by a concurrent pmap operation.
2967 	 */
2968 	VM_OBJECT_ASSERT_WLOCKED(m->object);
2969 	if (!vm_page_xbusied(m) && !pmap_page_is_write_mapped(m))
2970 		m->dirty &= ~pagebits;
2971 	else {
2972 		/*
2973 		 * The pmap layer can call vm_page_dirty() without
2974 		 * holding a distinguished lock.  The combination of
2975 		 * the object's lock and an atomic operation suffice
2976 		 * to guarantee consistency of the page dirty field.
2977 		 *
2978 		 * For PAGE_SIZE == 32768 case, compiler already
2979 		 * properly aligns the dirty field, so no forcible
2980 		 * alignment is needed. Only require existence of
2981 		 * atomic_clear_64 when page size is 32768.
2982 		 */
2983 		addr = (uintptr_t)&m->dirty;
2984 #if PAGE_SIZE == 32768
2985 		atomic_clear_64((uint64_t *)addr, pagebits);
2986 #elif PAGE_SIZE == 16384
2987 		atomic_clear_32((uint32_t *)addr, pagebits);
2988 #else		/* PAGE_SIZE <= 8192 */
2989 		/*
2990 		 * Use a trick to perform a 32-bit atomic on the
2991 		 * containing aligned word, to not depend on the existence
2992 		 * of atomic_clear_{8, 16}.
2993 		 */
2994 		shift = addr & (sizeof(uint32_t) - 1);
2995 #if BYTE_ORDER == BIG_ENDIAN
2996 		shift = (sizeof(uint32_t) - sizeof(m->dirty) - shift) * NBBY;
2997 #else
2998 		shift *= NBBY;
2999 #endif
3000 		addr &= ~(sizeof(uint32_t) - 1);
3001 		atomic_clear_32((uint32_t *)addr, pagebits << shift);
3002 #endif		/* PAGE_SIZE */
3003 	}
3004 }
3005 
3006 /*
3007  *	vm_page_set_validclean:
3008  *
3009  *	Sets portions of a page valid and clean.  The arguments are expected
3010  *	to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
3011  *	of any partial chunks touched by the range.  The invalid portion of
3012  *	such chunks will be zero'd.
3013  *
3014  *	(base + size) must be less then or equal to PAGE_SIZE.
3015  */
3016 void
3017 vm_page_set_validclean(vm_page_t m, int base, int size)
3018 {
3019 	vm_page_bits_t oldvalid, pagebits;
3020 	int endoff, frag;
3021 
3022 	VM_OBJECT_ASSERT_WLOCKED(m->object);
3023 	if (size == 0)	/* handle degenerate case */
3024 		return;
3025 
3026 	/*
3027 	 * If the base is not DEV_BSIZE aligned and the valid
3028 	 * bit is clear, we have to zero out a portion of the
3029 	 * first block.
3030 	 */
3031 	if ((frag = base & ~(DEV_BSIZE - 1)) != base &&
3032 	    (m->valid & ((vm_page_bits_t)1 << (base >> DEV_BSHIFT))) == 0)
3033 		pmap_zero_page_area(m, frag, base - frag);
3034 
3035 	/*
3036 	 * If the ending offset is not DEV_BSIZE aligned and the
3037 	 * valid bit is clear, we have to zero out a portion of
3038 	 * the last block.
3039 	 */
3040 	endoff = base + size;
3041 	if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff &&
3042 	    (m->valid & ((vm_page_bits_t)1 << (endoff >> DEV_BSHIFT))) == 0)
3043 		pmap_zero_page_area(m, endoff,
3044 		    DEV_BSIZE - (endoff & (DEV_BSIZE - 1)));
3045 
3046 	/*
3047 	 * Set valid, clear dirty bits.  If validating the entire
3048 	 * page we can safely clear the pmap modify bit.  We also
3049 	 * use this opportunity to clear the VPO_NOSYNC flag.  If a process
3050 	 * takes a write fault on a MAP_NOSYNC memory area the flag will
3051 	 * be set again.
3052 	 *
3053 	 * We set valid bits inclusive of any overlap, but we can only
3054 	 * clear dirty bits for DEV_BSIZE chunks that are fully within
3055 	 * the range.
3056 	 */
3057 	oldvalid = m->valid;
3058 	pagebits = vm_page_bits(base, size);
3059 	m->valid |= pagebits;
3060 #if 0	/* NOT YET */
3061 	if ((frag = base & (DEV_BSIZE - 1)) != 0) {
3062 		frag = DEV_BSIZE - frag;
3063 		base += frag;
3064 		size -= frag;
3065 		if (size < 0)
3066 			size = 0;
3067 	}
3068 	pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1));
3069 #endif
3070 	if (base == 0 && size == PAGE_SIZE) {
3071 		/*
3072 		 * The page can only be modified within the pmap if it is
3073 		 * mapped, and it can only be mapped if it was previously
3074 		 * fully valid.
3075 		 */
3076 		if (oldvalid == VM_PAGE_BITS_ALL)
3077 			/*
3078 			 * Perform the pmap_clear_modify() first.  Otherwise,
3079 			 * a concurrent pmap operation, such as
3080 			 * pmap_protect(), could clear a modification in the
3081 			 * pmap and set the dirty field on the page before
3082 			 * pmap_clear_modify() had begun and after the dirty
3083 			 * field was cleared here.
3084 			 */
3085 			pmap_clear_modify(m);
3086 		m->dirty = 0;
3087 		m->oflags &= ~VPO_NOSYNC;
3088 	} else if (oldvalid != VM_PAGE_BITS_ALL)
3089 		m->dirty &= ~pagebits;
3090 	else
3091 		vm_page_clear_dirty_mask(m, pagebits);
3092 }
3093 
3094 void
3095 vm_page_clear_dirty(vm_page_t m, int base, int size)
3096 {
3097 
3098 	vm_page_clear_dirty_mask(m, vm_page_bits(base, size));
3099 }
3100 
3101 /*
3102  *	vm_page_set_invalid:
3103  *
3104  *	Invalidates DEV_BSIZE'd chunks within a page.  Both the
3105  *	valid and dirty bits for the effected areas are cleared.
3106  */
3107 void
3108 vm_page_set_invalid(vm_page_t m, int base, int size)
3109 {
3110 	vm_page_bits_t bits;
3111 	vm_object_t object;
3112 
3113 	object = m->object;
3114 	VM_OBJECT_ASSERT_WLOCKED(object);
3115 	if (object->type == OBJT_VNODE && base == 0 && IDX_TO_OFF(m->pindex) +
3116 	    size >= object->un_pager.vnp.vnp_size)
3117 		bits = VM_PAGE_BITS_ALL;
3118 	else
3119 		bits = vm_page_bits(base, size);
3120 	if (object->ref_count != 0 && m->valid == VM_PAGE_BITS_ALL &&
3121 	    bits != 0)
3122 		pmap_remove_all(m);
3123 	KASSERT((bits == 0 && m->valid == VM_PAGE_BITS_ALL) ||
3124 	    !pmap_page_is_mapped(m),
3125 	    ("vm_page_set_invalid: page %p is mapped", m));
3126 	m->valid &= ~bits;
3127 	m->dirty &= ~bits;
3128 }
3129 
3130 /*
3131  * vm_page_zero_invalid()
3132  *
3133  *	The kernel assumes that the invalid portions of a page contain
3134  *	garbage, but such pages can be mapped into memory by user code.
3135  *	When this occurs, we must zero out the non-valid portions of the
3136  *	page so user code sees what it expects.
3137  *
3138  *	Pages are most often semi-valid when the end of a file is mapped
3139  *	into memory and the file's size is not page aligned.
3140  */
3141 void
3142 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
3143 {
3144 	int b;
3145 	int i;
3146 
3147 	VM_OBJECT_ASSERT_WLOCKED(m->object);
3148 	/*
3149 	 * Scan the valid bits looking for invalid sections that
3150 	 * must be zeroed.  Invalid sub-DEV_BSIZE'd areas ( where the
3151 	 * valid bit may be set ) have already been zeroed by
3152 	 * vm_page_set_validclean().
3153 	 */
3154 	for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
3155 		if (i == (PAGE_SIZE / DEV_BSIZE) ||
3156 		    (m->valid & ((vm_page_bits_t)1 << i))) {
3157 			if (i > b) {
3158 				pmap_zero_page_area(m,
3159 				    b << DEV_BSHIFT, (i - b) << DEV_BSHIFT);
3160 			}
3161 			b = i + 1;
3162 		}
3163 	}
3164 
3165 	/*
3166 	 * setvalid is TRUE when we can safely set the zero'd areas
3167 	 * as being valid.  We can do this if there are no cache consistancy
3168 	 * issues.  e.g. it is ok to do with UFS, but not ok to do with NFS.
3169 	 */
3170 	if (setvalid)
3171 		m->valid = VM_PAGE_BITS_ALL;
3172 }
3173 
3174 /*
3175  *	vm_page_is_valid:
3176  *
3177  *	Is (partial) page valid?  Note that the case where size == 0
3178  *	will return FALSE in the degenerate case where the page is
3179  *	entirely invalid, and TRUE otherwise.
3180  */
3181 int
3182 vm_page_is_valid(vm_page_t m, int base, int size)
3183 {
3184 	vm_page_bits_t bits;
3185 
3186 	VM_OBJECT_ASSERT_LOCKED(m->object);
3187 	bits = vm_page_bits(base, size);
3188 	return (m->valid != 0 && (m->valid & bits) == bits);
3189 }
3190 
3191 /*
3192  *	vm_page_ps_is_valid:
3193  *
3194  *	Returns TRUE if the entire (super)page is valid and FALSE otherwise.
3195  */
3196 boolean_t
3197 vm_page_ps_is_valid(vm_page_t m)
3198 {
3199 	int i, npages;
3200 
3201 	VM_OBJECT_ASSERT_LOCKED(m->object);
3202 	npages = atop(pagesizes[m->psind]);
3203 
3204 	/*
3205 	 * The physically contiguous pages that make up a superpage, i.e., a
3206 	 * page with a page size index ("psind") greater than zero, will
3207 	 * occupy adjacent entries in vm_page_array[].
3208 	 */
3209 	for (i = 0; i < npages; i++) {
3210 		if (m[i].valid != VM_PAGE_BITS_ALL)
3211 			return (FALSE);
3212 	}
3213 	return (TRUE);
3214 }
3215 
3216 /*
3217  * Set the page's dirty bits if the page is modified.
3218  */
3219 void
3220 vm_page_test_dirty(vm_page_t m)
3221 {
3222 
3223 	VM_OBJECT_ASSERT_WLOCKED(m->object);
3224 	if (m->dirty != VM_PAGE_BITS_ALL && pmap_is_modified(m))
3225 		vm_page_dirty(m);
3226 }
3227 
3228 void
3229 vm_page_lock_KBI(vm_page_t m, const char *file, int line)
3230 {
3231 
3232 	mtx_lock_flags_(vm_page_lockptr(m), 0, file, line);
3233 }
3234 
3235 void
3236 vm_page_unlock_KBI(vm_page_t m, const char *file, int line)
3237 {
3238 
3239 	mtx_unlock_flags_(vm_page_lockptr(m), 0, file, line);
3240 }
3241 
3242 int
3243 vm_page_trylock_KBI(vm_page_t m, const char *file, int line)
3244 {
3245 
3246 	return (mtx_trylock_flags_(vm_page_lockptr(m), 0, file, line));
3247 }
3248 
3249 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
3250 void
3251 vm_page_assert_locked_KBI(vm_page_t m, const char *file, int line)
3252 {
3253 
3254 	vm_page_lock_assert_KBI(m, MA_OWNED, file, line);
3255 }
3256 
3257 void
3258 vm_page_lock_assert_KBI(vm_page_t m, int a, const char *file, int line)
3259 {
3260 
3261 	mtx_assert_(vm_page_lockptr(m), a, file, line);
3262 }
3263 #endif
3264 
3265 #ifdef INVARIANTS
3266 void
3267 vm_page_object_lock_assert(vm_page_t m)
3268 {
3269 
3270 	/*
3271 	 * Certain of the page's fields may only be modified by the
3272 	 * holder of the containing object's lock or the exclusive busy.
3273 	 * holder.  Unfortunately, the holder of the write busy is
3274 	 * not recorded, and thus cannot be checked here.
3275 	 */
3276 	if (m->object != NULL && !vm_page_xbusied(m))
3277 		VM_OBJECT_ASSERT_WLOCKED(m->object);
3278 }
3279 
3280 void
3281 vm_page_assert_pga_writeable(vm_page_t m, uint8_t bits)
3282 {
3283 
3284 	if ((bits & PGA_WRITEABLE) == 0)
3285 		return;
3286 
3287 	/*
3288 	 * The PGA_WRITEABLE flag can only be set if the page is
3289 	 * managed, is exclusively busied or the object is locked.
3290 	 * Currently, this flag is only set by pmap_enter().
3291 	 */
3292 	KASSERT((m->oflags & VPO_UNMANAGED) == 0,
3293 	    ("PGA_WRITEABLE on unmanaged page"));
3294 	if (!vm_page_xbusied(m))
3295 		VM_OBJECT_ASSERT_LOCKED(m->object);
3296 }
3297 #endif
3298 
3299 #include "opt_ddb.h"
3300 #ifdef DDB
3301 #include <sys/kernel.h>
3302 
3303 #include <ddb/ddb.h>
3304 
3305 DB_SHOW_COMMAND(page, vm_page_print_page_info)
3306 {
3307 	db_printf("vm_cnt.v_free_count: %d\n", vm_cnt.v_free_count);
3308 	db_printf("vm_cnt.v_cache_count: %d\n", vm_cnt.v_cache_count);
3309 	db_printf("vm_cnt.v_inactive_count: %d\n", vm_cnt.v_inactive_count);
3310 	db_printf("vm_cnt.v_active_count: %d\n", vm_cnt.v_active_count);
3311 	db_printf("vm_cnt.v_wire_count: %d\n", vm_cnt.v_wire_count);
3312 	db_printf("vm_cnt.v_free_reserved: %d\n", vm_cnt.v_free_reserved);
3313 	db_printf("vm_cnt.v_free_min: %d\n", vm_cnt.v_free_min);
3314 	db_printf("vm_cnt.v_free_target: %d\n", vm_cnt.v_free_target);
3315 	db_printf("vm_cnt.v_inactive_target: %d\n", vm_cnt.v_inactive_target);
3316 }
3317 
3318 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
3319 {
3320 	int dom;
3321 
3322 	db_printf("pq_free %d pq_cache %d\n",
3323 	    vm_cnt.v_free_count, vm_cnt.v_cache_count);
3324 	for (dom = 0; dom < vm_ndomains; dom++) {
3325 		db_printf(
3326 	"dom %d page_cnt %d free %d pq_act %d pq_inact %d pass %d\n",
3327 		    dom,
3328 		    vm_dom[dom].vmd_page_count,
3329 		    vm_dom[dom].vmd_free_count,
3330 		    vm_dom[dom].vmd_pagequeues[PQ_ACTIVE].pq_cnt,
3331 		    vm_dom[dom].vmd_pagequeues[PQ_INACTIVE].pq_cnt,
3332 		    vm_dom[dom].vmd_pass);
3333 	}
3334 }
3335 
3336 DB_SHOW_COMMAND(pginfo, vm_page_print_pginfo)
3337 {
3338 	vm_page_t m;
3339 	boolean_t phys;
3340 
3341 	if (!have_addr) {
3342 		db_printf("show pginfo addr\n");
3343 		return;
3344 	}
3345 
3346 	phys = strchr(modif, 'p') != NULL;
3347 	if (phys)
3348 		m = PHYS_TO_VM_PAGE(addr);
3349 	else
3350 		m = (vm_page_t)addr;
3351 	db_printf(
3352     "page %p obj %p pidx 0x%jx phys 0x%jx q %d hold %d wire %d\n"
3353     "  af 0x%x of 0x%x f 0x%x act %d busy %x valid 0x%x dirty 0x%x\n",
3354 	    m, m->object, (uintmax_t)m->pindex, (uintmax_t)m->phys_addr,
3355 	    m->queue, m->hold_count, m->wire_count, m->aflags, m->oflags,
3356 	    m->flags, m->act_count, m->busy_lock, m->valid, m->dirty);
3357 }
3358 #endif /* DDB */
3359