4 * Copyright (c) 1991 Regents of the University of California.
7 * This code is derived from software contributed to Berkeley by
8 * The Mach Operating System project at Carnegie-Mellon University.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91
35 * $FreeBSD: src/sys/vm/vm_page.c,v 1.147.2.18 2002/03/10 05:03:19 alc Exp $
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
44 * Permission to use, copy, modify and distribute this software and
45 * its documentation is hereby granted, provided that both the copyright
46 * notice and this permission notice appear in all copies of the
47 * software, derivative works or modified versions, and any portions
48 * thereof, and that both notices appear in supporting documentation.
50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
54 * Carnegie Mellon requests users of this software to return to
56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
57 * School of Computer Science
58 * Carnegie Mellon University
59 * Pittsburgh PA 15213-3890
61 * any improvements or extensions that they make and grant Carnegie the
62 * rights to redistribute these changes.
65 * Resident memory management module. The module manipulates 'VM pages'.
66 * A VM page is the core building block for memory management.
69 #include <sys/param.h>
70 #include <sys/systm.h>
71 #include <sys/malloc.h>
73 #include <sys/vmmeter.h>
74 #include <sys/vnode.h>
75 #include <sys/kernel.h>
76 #include <sys/alist.h>
77 #include <sys/sysctl.h>
80 #include <vm/vm_param.h>
82 #include <vm/vm_kern.h>
84 #include <vm/vm_map.h>
85 #include <vm/vm_object.h>
86 #include <vm/vm_page.h>
87 #include <vm/vm_pageout.h>
88 #include <vm/vm_pager.h>
89 #include <vm/vm_extern.h>
90 #include <vm/swap_pager.h>
92 #include <machine/inttypes.h>
93 #include <machine/md_var.h>
94 #include <machine/specialreg.h>
96 #include <vm/vm_page2.h>
97 #include <sys/spinlock2.h>
99 #define VMACTION_HSIZE 256
100 #define VMACTION_HMASK (VMACTION_HSIZE - 1)
102 static void vm_page_queue_init(void);
103 static void vm_page_free_wakeup(void);
104 static vm_page_t vm_page_select_cache(u_short pg_color);
105 static vm_page_t _vm_page_list_find2(int basequeue, int index);
106 static void _vm_page_deactivate_locked(vm_page_t m, int athead);
109 * Array of tailq lists
111 __cachealign struct vpgqueues vm_page_queues[PQ_COUNT];
113 LIST_HEAD(vm_page_action_list, vm_page_action);
114 struct vm_page_action_list action_list[VMACTION_HSIZE];
115 static volatile int vm_pages_waiting;
117 static struct alist vm_contig_alist;
118 static struct almeta vm_contig_ameta[ALIST_RECORDS_65536];
119 static struct spinlock vm_contig_spin = SPINLOCK_INITIALIZER(&vm_contig_spin, "vm_contig_spin");
121 static u_long vm_dma_reserved = 0;
122 TUNABLE_ULONG("vm.dma_reserved", &vm_dma_reserved);
123 SYSCTL_ULONG(_vm, OID_AUTO, dma_reserved, CTLFLAG_RD, &vm_dma_reserved, 0,
124 "Memory reserved for DMA");
125 SYSCTL_UINT(_vm, OID_AUTO, dma_free_pages, CTLFLAG_RD,
126 &vm_contig_alist.bl_free, 0, "Memory reserved for DMA");
128 static int vm_contig_verbose = 0;
129 TUNABLE_INT("vm.contig_verbose", &vm_contig_verbose);
131 RB_GENERATE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare,
132 vm_pindex_t, pindex);
135 vm_page_queue_init(void)
139 for (i = 0; i < PQ_L2_SIZE; i++)
140 vm_page_queues[PQ_FREE+i].cnt = &vmstats.v_free_count;
141 for (i = 0; i < PQ_L2_SIZE; i++)
142 vm_page_queues[PQ_CACHE+i].cnt = &vmstats.v_cache_count;
143 for (i = 0; i < PQ_L2_SIZE; i++)
144 vm_page_queues[PQ_INACTIVE+i].cnt = &vmstats.v_inactive_count;
145 for (i = 0; i < PQ_L2_SIZE; i++)
146 vm_page_queues[PQ_ACTIVE+i].cnt = &vmstats.v_active_count;
147 for (i = 0; i < PQ_L2_SIZE; i++)
148 vm_page_queues[PQ_HOLD+i].cnt = &vmstats.v_active_count;
149 /* PQ_NONE has no queue */
151 for (i = 0; i < PQ_COUNT; i++) {
152 TAILQ_INIT(&vm_page_queues[i].pl);
153 spin_init(&vm_page_queues[i].spin, "vm_page_queue_init");
156 for (i = 0; i < VMACTION_HSIZE; i++)
157 LIST_INIT(&action_list[i]);
161 * note: place in initialized data section? Is this necessary?
164 int vm_page_array_size = 0;
165 int vm_page_zero_count = 0;
166 vm_page_t vm_page_array = NULL;
167 vm_paddr_t vm_low_phys_reserved;
172 * Sets the page size, perhaps based upon the memory size.
173 * Must be called before any use of page-size dependent functions.
176 vm_set_page_size(void)
178 if (vmstats.v_page_size == 0)
179 vmstats.v_page_size = PAGE_SIZE;
180 if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0)
181 panic("vm_set_page_size: page size not a power of two");
187 * Add a new page to the freelist for use by the system. New pages
188 * are added to both the head and tail of the associated free page
189 * queue in a bottom-up fashion, so both zero'd and non-zero'd page
190 * requests pull 'recent' adds (higher physical addresses) first.
192 * Beware that the page zeroing daemon will also be running soon after
193 * boot, moving pages from the head to the tail of the PQ_FREE queues.
195 * Must be called in a critical section.
198 vm_add_new_page(vm_paddr_t pa)
200 struct vpgqueues *vpq;
203 m = PHYS_TO_VM_PAGE(pa);
206 m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK;
207 m->pat_mode = PAT_WRITE_BACK;
209 * Twist for cpu localization in addition to page coloring, so
210 * different cpus selecting by m->queue get different page colors.
212 m->pc ^= ((pa >> PAGE_SHIFT) / PQ_L2_SIZE) & PQ_L2_MASK;
213 m->pc ^= ((pa >> PAGE_SHIFT) / (PQ_L2_SIZE * PQ_L2_SIZE)) & PQ_L2_MASK;
215 * Reserve a certain number of contiguous low memory pages for
216 * contigmalloc() to use.
218 if (pa < vm_low_phys_reserved) {
219 atomic_add_int(&vmstats.v_page_count, 1);
220 atomic_add_int(&vmstats.v_dma_pages, 1);
223 atomic_add_int(&vmstats.v_wire_count, 1);
224 alist_free(&vm_contig_alist, pa >> PAGE_SHIFT, 1);
231 m->queue = m->pc + PQ_FREE;
232 KKASSERT(m->dirty == 0);
234 atomic_add_int(&vmstats.v_page_count, 1);
235 atomic_add_int(&vmstats.v_free_count, 1);
236 vpq = &vm_page_queues[m->queue];
237 if ((vpq->flipflop & 15) == 0) {
238 pmap_zero_page(VM_PAGE_TO_PHYS(m));
240 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq);
241 atomic_add_int(&vm_page_zero_count, 1);
243 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq);
252 * Initializes the resident memory module.
254 * Preallocates memory for critical VM structures and arrays prior to
255 * kernel_map becoming available.
257 * Memory is allocated from (virtual2_start, virtual2_end) if available,
258 * otherwise memory is allocated from (virtual_start, virtual_end).
260 * On x86-64 (virtual_start, virtual_end) is only 2GB and may not be
261 * large enough to hold vm_page_array & other structures for machines with
262 * large amounts of ram, so we want to use virtual2* when available.
265 vm_page_startup(void)
267 vm_offset_t vaddr = virtual2_start ? virtual2_start : virtual_start;
270 vm_paddr_t page_range;
277 vm_paddr_t biggestone, biggestsize;
284 vaddr = round_page(vaddr);
286 for (i = 0; phys_avail[i + 1]; i += 2) {
287 phys_avail[i] = round_page64(phys_avail[i]);
288 phys_avail[i + 1] = trunc_page64(phys_avail[i + 1]);
291 for (i = 0; phys_avail[i + 1]; i += 2) {
292 vm_paddr_t size = phys_avail[i + 1] - phys_avail[i];
294 if (size > biggestsize) {
302 end = phys_avail[biggestone+1];
303 end = trunc_page(end);
306 * Initialize the queue headers for the free queue, the active queue
307 * and the inactive queue.
309 vm_page_queue_init();
311 #if !defined(_KERNEL_VIRTUAL)
313 * VKERNELs don't support minidumps and as such don't need
316 * Allocate a bitmap to indicate that a random physical page
317 * needs to be included in a minidump.
319 * The amd64 port needs this to indicate which direct map pages
320 * need to be dumped, via calls to dump_add_page()/dump_drop_page().
322 * However, i386 still needs this workspace internally within the
323 * minidump code. In theory, they are not needed on i386, but are
324 * included should the sf_buf code decide to use them.
326 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE;
327 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY);
328 end -= vm_page_dump_size;
329 vm_page_dump = (void *)pmap_map(&vaddr, end, end + vm_page_dump_size,
330 VM_PROT_READ | VM_PROT_WRITE);
331 bzero((void *)vm_page_dump, vm_page_dump_size);
334 * Compute the number of pages of memory that will be available for
335 * use (taking into account the overhead of a page structure per
338 first_page = phys_avail[0] / PAGE_SIZE;
339 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page;
340 npages = (total - (page_range * sizeof(struct vm_page))) / PAGE_SIZE;
342 #ifndef _KERNEL_VIRTUAL
344 * (only applies to real kernels)
346 * Initialize the contiguous reserve map. We initially reserve up
347 * to 1/4 available physical memory or 65536 pages (~256MB), whichever
350 * Once device initialization is complete we return most of the
351 * reserved memory back to the normal page queues but leave some
352 * in reserve for things like usb attachments.
354 vm_low_phys_reserved = (vm_paddr_t)65536 << PAGE_SHIFT;
355 if (vm_low_phys_reserved > total / 4)
356 vm_low_phys_reserved = total / 4;
357 if (vm_dma_reserved == 0) {
358 vm_dma_reserved = 16 * 1024 * 1024; /* 16MB */
359 if (vm_dma_reserved > total / 16)
360 vm_dma_reserved = total / 16;
363 alist_init(&vm_contig_alist, 65536, vm_contig_ameta,
364 ALIST_RECORDS_65536);
367 * Initialize the mem entry structures now, and put them in the free
370 new_end = trunc_page(end - page_range * sizeof(struct vm_page));
371 mapped = pmap_map(&vaddr, new_end, end, VM_PROT_READ | VM_PROT_WRITE);
372 vm_page_array = (vm_page_t)mapped;
374 #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL)
376 * since pmap_map on amd64 returns stuff out of a direct-map region,
377 * we have to manually add these pages to the minidump tracking so
378 * that they can be dumped, including the vm_page_array.
380 for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE)
385 * Clear all of the page structures
387 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page));
388 vm_page_array_size = page_range;
391 * Construct the free queue(s) in ascending order (by physical
392 * address) so that the first 16MB of physical memory is allocated
393 * last rather than first. On large-memory machines, this avoids
394 * the exhaustion of low physical memory before isa_dmainit has run.
396 vmstats.v_page_count = 0;
397 vmstats.v_free_count = 0;
398 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) {
403 last_pa = phys_avail[i + 1];
404 while (pa < last_pa && npages-- > 0) {
410 virtual2_start = vaddr;
412 virtual_start = vaddr;
416 * We tended to reserve a ton of memory for contigmalloc(). Now that most
417 * drivers have initialized we want to return most the remaining free
418 * reserve back to the VM page queues so they can be used for normal
421 * We leave vm_dma_reserved bytes worth of free pages in the reserve pool.
424 vm_page_startup_finish(void *dummy __unused)
433 spin_lock(&vm_contig_spin);
435 bfree = alist_free_info(&vm_contig_alist, &blk, &count);
436 if (bfree <= vm_dma_reserved / PAGE_SIZE)
442 * Figure out how much of the initial reserve we have to
443 * free in order to reach our target.
445 bfree -= vm_dma_reserved / PAGE_SIZE;
447 blk += count - bfree;
452 * Calculate the nearest power of 2 <= count.
454 for (xcount = 1; xcount <= count; xcount <<= 1)
457 blk += count - xcount;
461 * Allocate the pages from the alist, then free them to
462 * the normal VM page queues.
464 * Pages allocated from the alist are wired. We have to
465 * busy, unwire, and free them. We must also adjust
466 * vm_low_phys_reserved before freeing any pages to prevent
469 rblk = alist_alloc(&vm_contig_alist, blk, count);
471 kprintf("vm_page_startup_finish: Unable to return "
472 "dma space @0x%08x/%d -> 0x%08x\n",
476 atomic_add_int(&vmstats.v_dma_pages, -count);
477 spin_unlock(&vm_contig_spin);
479 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT);
480 vm_low_phys_reserved = VM_PAGE_TO_PHYS(m);
482 vm_page_busy_wait(m, FALSE, "cpgfr");
483 vm_page_unwire(m, 0);
488 spin_lock(&vm_contig_spin);
490 spin_unlock(&vm_contig_spin);
493 * Print out how much DMA space drivers have already allocated and
494 * how much is left over.
496 kprintf("DMA space used: %jdk, remaining available: %jdk\n",
497 (intmax_t)(vmstats.v_dma_pages - vm_contig_alist.bl_free) *
499 (intmax_t)vm_contig_alist.bl_free * (PAGE_SIZE / 1024));
501 SYSINIT(vm_pgend, SI_SUB_PROC0_POST, SI_ORDER_ANY,
502 vm_page_startup_finish, NULL);
506 * Scan comparison function for Red-Black tree scans. An inclusive
507 * (start,end) is expected. Other fields are not used.
510 rb_vm_page_scancmp(struct vm_page *p, void *data)
512 struct rb_vm_page_scan_info *info = data;
514 if (p->pindex < info->start_pindex)
516 if (p->pindex > info->end_pindex)
522 rb_vm_page_compare(struct vm_page *p1, struct vm_page *p2)
524 if (p1->pindex < p2->pindex)
526 if (p1->pindex > p2->pindex)
532 vm_page_init(vm_page_t m)
534 /* do nothing for now. Called from pmap_page_init() */
538 * Each page queue has its own spin lock, which is fairly optimal for
539 * allocating and freeing pages at least.
541 * The caller must hold the vm_page_spin_lock() before locking a vm_page's
542 * queue spinlock via this function. Also note that m->queue cannot change
543 * unless both the page and queue are locked.
547 _vm_page_queue_spin_lock(vm_page_t m)
552 if (queue != PQ_NONE) {
553 spin_lock(&vm_page_queues[queue].spin);
554 KKASSERT(queue == m->queue);
560 _vm_page_queue_spin_unlock(vm_page_t m)
566 if (queue != PQ_NONE)
567 spin_unlock(&vm_page_queues[queue].spin);
572 _vm_page_queues_spin_lock(u_short queue)
575 if (queue != PQ_NONE)
576 spin_lock(&vm_page_queues[queue].spin);
582 _vm_page_queues_spin_unlock(u_short queue)
585 if (queue != PQ_NONE)
586 spin_unlock(&vm_page_queues[queue].spin);
590 vm_page_queue_spin_lock(vm_page_t m)
592 _vm_page_queue_spin_lock(m);
596 vm_page_queues_spin_lock(u_short queue)
598 _vm_page_queues_spin_lock(queue);
602 vm_page_queue_spin_unlock(vm_page_t m)
604 _vm_page_queue_spin_unlock(m);
608 vm_page_queues_spin_unlock(u_short queue)
610 _vm_page_queues_spin_unlock(queue);
614 * This locks the specified vm_page and its queue in the proper order
615 * (page first, then queue). The queue may change so the caller must
620 _vm_page_and_queue_spin_lock(vm_page_t m)
622 vm_page_spin_lock(m);
623 _vm_page_queue_spin_lock(m);
628 _vm_page_and_queue_spin_unlock(vm_page_t m)
630 _vm_page_queues_spin_unlock(m->queue);
631 vm_page_spin_unlock(m);
635 vm_page_and_queue_spin_unlock(vm_page_t m)
637 _vm_page_and_queue_spin_unlock(m);
641 vm_page_and_queue_spin_lock(vm_page_t m)
643 _vm_page_and_queue_spin_lock(m);
647 * Helper function removes vm_page from its current queue.
648 * Returns the base queue the page used to be on.
650 * The vm_page and the queue must be spinlocked.
651 * This function will unlock the queue but leave the page spinlocked.
653 static __inline u_short
654 _vm_page_rem_queue_spinlocked(vm_page_t m)
656 struct vpgqueues *pq;
660 if (queue != PQ_NONE) {
661 pq = &vm_page_queues[queue];
662 TAILQ_REMOVE(&pq->pl, m, pageq);
663 atomic_add_int(pq->cnt, -1);
666 vm_page_queues_spin_unlock(queue);
667 if ((queue - m->pc) == PQ_FREE && (m->flags & PG_ZERO))
668 atomic_subtract_int(&vm_page_zero_count, 1);
669 if ((queue - m->pc) == PQ_CACHE || (queue - m->pc) == PQ_FREE)
670 return (queue - m->pc);
676 * Helper function places the vm_page on the specified queue.
678 * The vm_page must be spinlocked.
679 * This function will return with both the page and the queue locked.
682 _vm_page_add_queue_spinlocked(vm_page_t m, u_short queue, int athead)
684 struct vpgqueues *pq;
686 KKASSERT(m->queue == PQ_NONE);
688 if (queue != PQ_NONE) {
689 vm_page_queues_spin_lock(queue);
690 pq = &vm_page_queues[queue];
692 atomic_add_int(pq->cnt, 1);
696 * Put zero'd pages on the end ( where we look for zero'd pages
697 * first ) and non-zerod pages at the head.
699 if (queue - m->pc == PQ_FREE) {
700 if (m->flags & PG_ZERO) {
701 TAILQ_INSERT_TAIL(&pq->pl, m, pageq);
702 atomic_add_int(&vm_page_zero_count, 1);
704 TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
707 TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
709 TAILQ_INSERT_TAIL(&pq->pl, m, pageq);
711 /* leave the queue spinlocked */
716 * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE)
717 * m->busy is zero. Returns TRUE if it had to sleep, FALSE if we
718 * did not. Only one sleep call will be made before returning.
720 * This function does NOT busy the page and on return the page is not
721 * guaranteed to be available.
724 vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg)
732 if ((flags & PG_BUSY) == 0 &&
733 (also_m_busy == 0 || (flags & PG_SBUSY) == 0)) {
736 tsleep_interlock(m, 0);
737 if (atomic_cmpset_int(&m->flags, flags,
738 flags | PG_WANTED | PG_REFERENCED)) {
739 tsleep(m, PINTERLOCKED, msg, 0);
746 * Wait until PG_BUSY can be set, then set it. If also_m_busy is TRUE we
747 * also wait for m->busy to become 0 before setting PG_BUSY.
750 VM_PAGE_DEBUG_EXT(vm_page_busy_wait)(vm_page_t m,
751 int also_m_busy, const char *msg
759 if (flags & PG_BUSY) {
760 tsleep_interlock(m, 0);
761 if (atomic_cmpset_int(&m->flags, flags,
762 flags | PG_WANTED | PG_REFERENCED)) {
763 tsleep(m, PINTERLOCKED, msg, 0);
765 } else if (also_m_busy && (flags & PG_SBUSY)) {
766 tsleep_interlock(m, 0);
767 if (atomic_cmpset_int(&m->flags, flags,
768 flags | PG_WANTED | PG_REFERENCED)) {
769 tsleep(m, PINTERLOCKED, msg, 0);
772 if (atomic_cmpset_int(&m->flags, flags,
776 m->busy_line = lineno;
785 * Attempt to set PG_BUSY. If also_m_busy is TRUE we only succeed if m->busy
788 * Returns non-zero on failure.
791 VM_PAGE_DEBUG_EXT(vm_page_busy_try)(vm_page_t m, int also_m_busy
801 if (also_m_busy && (flags & PG_SBUSY))
803 if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) {
806 m->busy_line = lineno;
814 * Clear the PG_BUSY flag and return non-zero to indicate to the caller
815 * that a wakeup() should be performed.
817 * The vm_page must be spinlocked and will remain spinlocked on return.
818 * The related queue must NOT be spinlocked (which could deadlock us).
824 _vm_page_wakeup(vm_page_t m)
831 if (atomic_cmpset_int(&m->flags, flags,
832 flags & ~(PG_BUSY | PG_WANTED))) {
836 return(flags & PG_WANTED);
840 * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This
841 * is typically the last call you make on a page before moving onto
845 vm_page_wakeup(vm_page_t m)
847 KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!"));
848 vm_page_spin_lock(m);
849 if (_vm_page_wakeup(m)) {
850 vm_page_spin_unlock(m);
853 vm_page_spin_unlock(m);
858 * Holding a page keeps it from being reused. Other parts of the system
859 * can still disassociate the page from its current object and free it, or
860 * perform read or write I/O on it and/or otherwise manipulate the page,
861 * but if the page is held the VM system will leave the page and its data
862 * intact and not reuse the page for other purposes until the last hold
863 * reference is released. (see vm_page_wire() if you want to prevent the
864 * page from being disassociated from its object too).
866 * The caller must still validate the contents of the page and, if necessary,
867 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete
868 * before manipulating the page.
870 * XXX get vm_page_spin_lock() here and move FREE->HOLD if necessary
873 vm_page_hold(vm_page_t m)
875 vm_page_spin_lock(m);
876 atomic_add_int(&m->hold_count, 1);
877 if (m->queue - m->pc == PQ_FREE) {
878 _vm_page_queue_spin_lock(m);
879 _vm_page_rem_queue_spinlocked(m);
880 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0);
881 _vm_page_queue_spin_unlock(m);
883 vm_page_spin_unlock(m);
887 * The opposite of vm_page_hold(). If the page is on the HOLD queue
888 * it was freed while held and must be moved back to the FREE queue.
891 vm_page_unhold(vm_page_t m)
893 KASSERT(m->hold_count > 0 && m->queue - m->pc != PQ_FREE,
894 ("vm_page_unhold: pg %p illegal hold_count (%d) or on FREE queue (%d)",
895 m, m->hold_count, m->queue - m->pc));
896 vm_page_spin_lock(m);
897 atomic_add_int(&m->hold_count, -1);
898 if (m->hold_count == 0 && m->queue - m->pc == PQ_HOLD) {
899 _vm_page_queue_spin_lock(m);
900 _vm_page_rem_queue_spinlocked(m);
901 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0);
902 _vm_page_queue_spin_unlock(m);
904 vm_page_spin_unlock(m);
910 * Create a fictitious page with the specified physical address and
911 * memory attribute. The memory attribute is the only the machine-
912 * dependent aspect of a fictitious page that must be initialized.
916 vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
919 if ((m->flags & PG_FICTITIOUS) != 0) {
921 * The page's memattr might have changed since the
922 * previous initialization. Update the pmap to the
927 m->phys_addr = paddr;
929 /* Fictitious pages don't use "segind". */
930 /* Fictitious pages don't use "order" or "pool". */
931 m->flags = PG_FICTITIOUS | PG_UNMANAGED | PG_BUSY;
935 pmap_page_set_memattr(m, memattr);
939 * Inserts the given vm_page into the object and object list.
941 * The pagetables are not updated but will presumably fault the page
942 * in if necessary, or if a kernel page the caller will at some point
943 * enter the page into the kernel's pmap. We are not allowed to block
944 * here so we *can't* do this anyway.
946 * This routine may not block.
947 * This routine must be called with the vm_object held.
948 * This routine must be called with a critical section held.
950 * This routine returns TRUE if the page was inserted into the object
951 * successfully, and FALSE if the page already exists in the object.
954 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
956 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(object));
957 if (m->object != NULL)
958 panic("vm_page_insert: already inserted");
960 object->generation++;
963 * Record the object/offset pair in this page and add the
964 * pv_list_count of the page to the object.
966 * The vm_page spin lock is required for interactions with the pmap.
968 vm_page_spin_lock(m);
971 if (vm_page_rb_tree_RB_INSERT(&object->rb_memq, m)) {
974 vm_page_spin_unlock(m);
977 ++object->resident_page_count;
978 ++mycpu->gd_vmtotal.t_rm;
979 /* atomic_add_int(&object->agg_pv_list_count, m->md.pv_list_count); */
980 vm_page_spin_unlock(m);
983 * Since we are inserting a new and possibly dirty page,
984 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags.
986 if ((m->valid & m->dirty) ||
987 (m->flags & (PG_WRITEABLE | PG_NEED_COMMIT)))
988 vm_object_set_writeable_dirty(object);
991 * Checks for a swap assignment and sets PG_SWAPPED if appropriate.
993 swap_pager_page_inserted(m);
998 * Removes the given vm_page_t from the (object,index) table
1000 * The underlying pmap entry (if any) is NOT removed here.
1001 * This routine may not block.
1003 * The page must be BUSY and will remain BUSY on return.
1004 * No other requirements.
1006 * NOTE: FreeBSD side effect was to unbusy the page on return. We leave
1010 vm_page_remove(vm_page_t m)
1014 if (m->object == NULL) {
1018 if ((m->flags & PG_BUSY) == 0)
1019 panic("vm_page_remove: page not busy");
1023 vm_object_hold(object);
1026 * Remove the page from the object and update the object.
1028 * The vm_page spin lock is required for interactions with the pmap.
1030 vm_page_spin_lock(m);
1031 vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m);
1032 --object->resident_page_count;
1033 --mycpu->gd_vmtotal.t_rm;
1034 /* atomic_add_int(&object->agg_pv_list_count, -m->md.pv_list_count); */
1036 vm_page_spin_unlock(m);
1038 object->generation++;
1040 vm_object_drop(object);
1044 * Locate and return the page at (object, pindex), or NULL if the
1045 * page could not be found.
1047 * The caller must hold the vm_object token.
1050 vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
1055 * Search the hash table for this object/offset pair
1057 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
1058 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
1059 KKASSERT(m == NULL || (m->object == object && m->pindex == pindex));
1064 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait)(struct vm_object *object,
1066 int also_m_busy, const char *msg
1072 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
1073 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
1075 KKASSERT(m->object == object && m->pindex == pindex);
1078 if (flags & PG_BUSY) {
1079 tsleep_interlock(m, 0);
1080 if (atomic_cmpset_int(&m->flags, flags,
1081 flags | PG_WANTED | PG_REFERENCED)) {
1082 tsleep(m, PINTERLOCKED, msg, 0);
1083 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq,
1086 } else if (also_m_busy && (flags & PG_SBUSY)) {
1087 tsleep_interlock(m, 0);
1088 if (atomic_cmpset_int(&m->flags, flags,
1089 flags | PG_WANTED | PG_REFERENCED)) {
1090 tsleep(m, PINTERLOCKED, msg, 0);
1091 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq,
1094 } else if (atomic_cmpset_int(&m->flags, flags,
1096 #ifdef VM_PAGE_DEBUG
1097 m->busy_func = func;
1098 m->busy_line = lineno;
1107 * Attempt to lookup and busy a page.
1109 * Returns NULL if the page could not be found
1111 * Returns a vm_page and error == TRUE if the page exists but could not
1114 * Returns a vm_page and error == FALSE on success.
1117 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try)(struct vm_object *object,
1119 int also_m_busy, int *errorp
1125 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
1126 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
1129 KKASSERT(m->object == object && m->pindex == pindex);
1132 if (flags & PG_BUSY) {
1136 if (also_m_busy && (flags & PG_SBUSY)) {
1140 if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) {
1141 #ifdef VM_PAGE_DEBUG
1142 m->busy_func = func;
1143 m->busy_line = lineno;
1152 * Caller must hold the related vm_object
1155 vm_page_next(vm_page_t m)
1159 next = vm_page_rb_tree_RB_NEXT(m);
1160 if (next && next->pindex != m->pindex + 1)
1168 * Move the given vm_page from its current object to the specified
1169 * target object/offset. The page must be busy and will remain so
1172 * new_object must be held.
1173 * This routine might block. XXX ?
1175 * NOTE: Swap associated with the page must be invalidated by the move. We
1176 * have to do this for several reasons: (1) we aren't freeing the
1177 * page, (2) we are dirtying the page, (3) the VM system is probably
1178 * moving the page from object A to B, and will then later move
1179 * the backing store from A to B and we can't have a conflict.
1181 * NOTE: We *always* dirty the page. It is necessary both for the
1182 * fact that we moved it, and because we may be invalidating
1183 * swap. If the page is on the cache, we have to deactivate it
1184 * or vm_page_dirty() will panic. Dirty pages are not allowed
1188 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
1190 KKASSERT(m->flags & PG_BUSY);
1191 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(new_object));
1193 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(m->object));
1196 if (vm_page_insert(m, new_object, new_pindex) == FALSE) {
1197 panic("vm_page_rename: target exists (%p,%"PRIu64")",
1198 new_object, new_pindex);
1200 if (m->queue - m->pc == PQ_CACHE)
1201 vm_page_deactivate(m);
1206 * vm_page_unqueue() without any wakeup. This routine is used when a page
1207 * is to remain BUSYied by the caller.
1209 * This routine may not block.
1212 vm_page_unqueue_nowakeup(vm_page_t m)
1214 vm_page_and_queue_spin_lock(m);
1215 (void)_vm_page_rem_queue_spinlocked(m);
1216 vm_page_spin_unlock(m);
1220 * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon
1223 * This routine may not block.
1226 vm_page_unqueue(vm_page_t m)
1230 vm_page_and_queue_spin_lock(m);
1231 queue = _vm_page_rem_queue_spinlocked(m);
1232 if (queue == PQ_FREE || queue == PQ_CACHE) {
1233 vm_page_spin_unlock(m);
1234 pagedaemon_wakeup();
1236 vm_page_spin_unlock(m);
1241 * vm_page_list_find()
1243 * Find a page on the specified queue with color optimization.
1245 * The page coloring optimization attempts to locate a page that does
1246 * not overload other nearby pages in the object in the cpu's L1 or L2
1247 * caches. We need this optimization because cpu caches tend to be
1248 * physical caches, while object spaces tend to be virtual.
1250 * On MP systems each PQ_FREE and PQ_CACHE color queue has its own spinlock
1251 * and the algorithm is adjusted to localize allocations on a per-core basis.
1252 * This is done by 'twisting' the colors.
1254 * The page is returned spinlocked and removed from its queue (it will
1255 * be on PQ_NONE), or NULL. The page is not PG_BUSY'd. The caller
1256 * is responsible for dealing with the busy-page case (usually by
1257 * deactivating the page and looping).
1259 * NOTE: This routine is carefully inlined. A non-inlined version
1260 * is available for outside callers but the only critical path is
1261 * from within this source file.
1263 * NOTE: This routine assumes that the vm_pages found in PQ_CACHE and PQ_FREE
1264 * represent stable storage, allowing us to order our locks vm_page
1265 * first, then queue.
1269 _vm_page_list_find(int basequeue, int index, boolean_t prefer_zero)
1275 m = TAILQ_LAST(&vm_page_queues[basequeue+index].pl, pglist);
1277 m = TAILQ_FIRST(&vm_page_queues[basequeue+index].pl);
1279 m = _vm_page_list_find2(basequeue, index);
1282 vm_page_and_queue_spin_lock(m);
1283 if (m->queue == basequeue + index) {
1284 _vm_page_rem_queue_spinlocked(m);
1285 /* vm_page_t spin held, no queue spin */
1288 vm_page_and_queue_spin_unlock(m);
1294 _vm_page_list_find2(int basequeue, int index)
1298 struct vpgqueues *pq;
1300 pq = &vm_page_queues[basequeue];
1303 * Note that for the first loop, index+i and index-i wind up at the
1304 * same place. Even though this is not totally optimal, we've already
1305 * blown it by missing the cache case so we do not care.
1307 for (i = PQ_L2_SIZE / 2; i > 0; --i) {
1309 m = TAILQ_FIRST(&pq[(index + i) & PQ_L2_MASK].pl);
1311 _vm_page_and_queue_spin_lock(m);
1313 basequeue + ((index + i) & PQ_L2_MASK)) {
1314 _vm_page_rem_queue_spinlocked(m);
1317 _vm_page_and_queue_spin_unlock(m);
1320 m = TAILQ_FIRST(&pq[(index - i) & PQ_L2_MASK].pl);
1322 _vm_page_and_queue_spin_lock(m);
1324 basequeue + ((index - i) & PQ_L2_MASK)) {
1325 _vm_page_rem_queue_spinlocked(m);
1328 _vm_page_and_queue_spin_unlock(m);
1338 * Returns a vm_page candidate for allocation. The page is not busied so
1339 * it can move around. The caller must busy the page (and typically
1340 * deactivate it if it cannot be busied!)
1342 * Returns a spinlocked vm_page that has been removed from its queue.
1345 vm_page_list_find(int basequeue, int index, boolean_t prefer_zero)
1347 return(_vm_page_list_find(basequeue, index, prefer_zero));
1351 * Find a page on the cache queue with color optimization, remove it
1352 * from the queue, and busy it. The returned page will not be spinlocked.
1354 * A candidate failure will be deactivated. Candidates can fail due to
1355 * being busied by someone else, in which case they will be deactivated.
1357 * This routine may not block.
1361 vm_page_select_cache(u_short pg_color)
1366 m = _vm_page_list_find(PQ_CACHE, pg_color & PQ_L2_MASK, FALSE);
1370 * (m) has been removed from its queue and spinlocked
1372 if (vm_page_busy_try(m, TRUE)) {
1373 _vm_page_deactivate_locked(m, 0);
1374 vm_page_spin_unlock(m);
1377 * We successfully busied the page
1379 if ((m->flags & (PG_UNMANAGED | PG_NEED_COMMIT)) == 0 &&
1380 m->hold_count == 0 &&
1381 m->wire_count == 0 &&
1382 (m->dirty & m->valid) == 0) {
1383 vm_page_spin_unlock(m);
1384 pagedaemon_wakeup();
1389 * The page cannot be recycled, deactivate it.
1391 _vm_page_deactivate_locked(m, 0);
1392 if (_vm_page_wakeup(m)) {
1393 vm_page_spin_unlock(m);
1396 vm_page_spin_unlock(m);
1404 * Find a free or zero page, with specified preference. We attempt to
1405 * inline the nominal case and fall back to _vm_page_select_free()
1406 * otherwise. A busied page is removed from the queue and returned.
1408 * This routine may not block.
1410 static __inline vm_page_t
1411 vm_page_select_free(u_short pg_color, boolean_t prefer_zero)
1416 m = _vm_page_list_find(PQ_FREE, pg_color & PQ_L2_MASK,
1420 if (vm_page_busy_try(m, TRUE)) {
1422 * Various mechanisms such as a pmap_collect can
1423 * result in a busy page on the free queue. We
1424 * have to move the page out of the way so we can
1425 * retry the allocation. If the other thread is not
1426 * allocating the page then m->valid will remain 0 and
1427 * the pageout daemon will free the page later on.
1429 * Since we could not busy the page, however, we
1430 * cannot make assumptions as to whether the page
1431 * will be allocated by the other thread or not,
1432 * so all we can do is deactivate it to move it out
1433 * of the way. In particular, if the other thread
1434 * wires the page it may wind up on the inactive
1435 * queue and the pageout daemon will have to deal
1436 * with that case too.
1438 _vm_page_deactivate_locked(m, 0);
1439 vm_page_spin_unlock(m);
1442 * Theoretically if we are able to busy the page
1443 * atomic with the queue removal (using the vm_page
1444 * lock) nobody else should be able to mess with the
1447 KKASSERT((m->flags & (PG_UNMANAGED |
1448 PG_NEED_COMMIT)) == 0);
1449 KASSERT(m->hold_count == 0, ("m->hold_count is not zero "
1450 "pg %p q=%d flags=%08x hold=%d wire=%d",
1451 m, m->queue, m->flags, m->hold_count, m->wire_count));
1452 KKASSERT(m->wire_count == 0);
1453 vm_page_spin_unlock(m);
1454 pagedaemon_wakeup();
1456 /* return busied and removed page */
1464 * This implements a per-cpu cache of free, zero'd, ready-to-go pages.
1465 * The idea is to populate this cache prior to acquiring any locks so
1466 * we don't wind up potentially zeroing VM pages (under heavy loads) while
1467 * holding potentialy contending locks.
1469 * Note that we allocate the page uninserted into anything and use a pindex
1470 * of 0, the vm_page_alloc() will effectively add gd_cpuid so these
1471 * allocations should wind up being uncontended. However, we still want
1472 * to rove across PQ_L2_SIZE.
1475 vm_page_pcpu_cache(void)
1478 globaldata_t gd = mycpu;
1481 if (gd->gd_vmpg_count < GD_MINVMPG) {
1483 while (gd->gd_vmpg_count < GD_MAXVMPG) {
1484 m = vm_page_alloc(NULL, ticks & ~ncpus2_mask,
1485 VM_ALLOC_NULL_OK | VM_ALLOC_NORMAL |
1486 VM_ALLOC_NULL_OK | VM_ALLOC_ZERO);
1487 if (gd->gd_vmpg_count < GD_MAXVMPG) {
1488 if ((m->flags & PG_ZERO) == 0) {
1489 pmap_zero_page(VM_PAGE_TO_PHYS(m));
1490 vm_page_flag_set(m, PG_ZERO);
1492 gd->gd_vmpg_array[gd->gd_vmpg_count++] = m;
1505 * Allocate and return a memory cell associated with this VM object/offset
1506 * pair. If object is NULL an unassociated page will be allocated.
1508 * The returned page will be busied and removed from its queues. This
1509 * routine can block and may return NULL if a race occurs and the page
1510 * is found to already exist at the specified (object, pindex).
1512 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain
1513 * VM_ALLOC_QUICK like normal but cannot use cache
1514 * VM_ALLOC_SYSTEM greater free drain
1515 * VM_ALLOC_INTERRUPT allow free list to be completely drained
1516 * VM_ALLOC_ZERO advisory request for pre-zero'd page only
1517 * VM_ALLOC_FORCE_ZERO advisory request for pre-zero'd page only
1518 * VM_ALLOC_NULL_OK ok to return NULL on insertion collision
1519 * (see vm_page_grab())
1520 * VM_ALLOC_USE_GD ok to use per-gd cache
1522 * The object must be held if not NULL
1523 * This routine may not block
1525 * Additional special handling is required when called from an interrupt
1526 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache
1530 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req)
1532 globaldata_t gd = mycpu;
1539 * Special per-cpu free VM page cache. The pages are pre-busied
1540 * and pre-zerod for us.
1542 if (gd->gd_vmpg_count && (page_req & VM_ALLOC_USE_GD)) {
1544 if (gd->gd_vmpg_count) {
1545 m = gd->gd_vmpg_array[--gd->gd_vmpg_count];
1555 * Cpu twist - cpu localization algorithm
1558 pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask) +
1559 (object->pg_color & ~ncpus_fit_mask);
1561 pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask);
1564 (VM_ALLOC_NORMAL|VM_ALLOC_QUICK|
1565 VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
1568 * Certain system threads (pageout daemon, buf_daemon's) are
1569 * allowed to eat deeper into the free page list.
1571 if (curthread->td_flags & TDF_SYSTHREAD)
1572 page_req |= VM_ALLOC_SYSTEM;
1575 if (vmstats.v_free_count > vmstats.v_free_reserved ||
1576 ((page_req & VM_ALLOC_INTERRUPT) && vmstats.v_free_count > 0) ||
1577 ((page_req & VM_ALLOC_SYSTEM) && vmstats.v_cache_count == 0 &&
1578 vmstats.v_free_count > vmstats.v_interrupt_free_min)
1581 * The free queue has sufficient free pages to take one out.
1583 if (page_req & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO))
1584 m = vm_page_select_free(pg_color, TRUE);
1586 m = vm_page_select_free(pg_color, FALSE);
1587 } else if (page_req & VM_ALLOC_NORMAL) {
1589 * Allocatable from the cache (non-interrupt only). On
1590 * success, we must free the page and try again, thus
1591 * ensuring that vmstats.v_*_free_min counters are replenished.
1594 if (curthread->td_preempted) {
1595 kprintf("vm_page_alloc(): warning, attempt to allocate"
1596 " cache page from preempting interrupt\n");
1599 m = vm_page_select_cache(pg_color);
1602 m = vm_page_select_cache(pg_color);
1605 * On success move the page into the free queue and loop.
1607 * Only do this if we can safely acquire the vm_object lock,
1608 * because this is effectively a random page and the caller
1609 * might be holding the lock shared, we don't want to
1613 KASSERT(m->dirty == 0,
1614 ("Found dirty cache page %p", m));
1615 if ((obj = m->object) != NULL) {
1616 if (vm_object_hold_try(obj)) {
1617 vm_page_protect(m, VM_PROT_NONE);
1619 /* m->object NULL here */
1620 vm_object_drop(obj);
1622 vm_page_deactivate(m);
1626 vm_page_protect(m, VM_PROT_NONE);
1633 * On failure return NULL
1635 #if defined(DIAGNOSTIC)
1636 if (vmstats.v_cache_count > 0)
1637 kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats.v_cache_count);
1639 vm_pageout_deficit++;
1640 pagedaemon_wakeup();
1644 * No pages available, wakeup the pageout daemon and give up.
1646 vm_pageout_deficit++;
1647 pagedaemon_wakeup();
1652 * v_free_count can race so loop if we don't find the expected
1659 * Good page found. The page has already been busied for us and
1660 * removed from its queues.
1662 KASSERT(m->dirty == 0,
1663 ("vm_page_alloc: free/cache page %p was dirty", m));
1664 KKASSERT(m->queue == PQ_NONE);
1670 * Initialize the structure, inheriting some flags but clearing
1671 * all the rest. The page has already been busied for us.
1673 vm_page_flag_clear(m, ~(PG_ZERO | PG_BUSY | PG_SBUSY));
1674 KKASSERT(m->wire_count == 0);
1675 KKASSERT(m->busy == 0);
1680 * Caller must be holding the object lock (asserted by
1681 * vm_page_insert()).
1683 * NOTE: Inserting a page here does not insert it into any pmaps
1684 * (which could cause us to block allocating memory).
1686 * NOTE: If no object an unassociated page is allocated, m->pindex
1687 * can be used by the caller for any purpose.
1690 if (vm_page_insert(m, object, pindex) == FALSE) {
1692 if ((page_req & VM_ALLOC_NULL_OK) == 0)
1693 panic("PAGE RACE %p[%ld]/%p",
1694 object, (long)pindex, m);
1702 * Don't wakeup too often - wakeup the pageout daemon when
1703 * we would be nearly out of memory.
1705 pagedaemon_wakeup();
1708 * A PG_BUSY page is returned.
1714 * Returns number of pages available in our DMA memory reserve
1715 * (adjusted with vm.dma_reserved=<value>m in /boot/loader.conf)
1718 vm_contig_avail_pages(void)
1723 spin_lock(&vm_contig_spin);
1724 bfree = alist_free_info(&vm_contig_alist, &blk, &count);
1725 spin_unlock(&vm_contig_spin);
1731 * Attempt to allocate contiguous physical memory with the specified
1735 vm_page_alloc_contig(vm_paddr_t low, vm_paddr_t high,
1736 unsigned long alignment, unsigned long boundary,
1737 unsigned long size, vm_memattr_t memattr)
1743 alignment >>= PAGE_SHIFT;
1746 boundary >>= PAGE_SHIFT;
1749 size = (size + PAGE_MASK) >> PAGE_SHIFT;
1751 spin_lock(&vm_contig_spin);
1752 blk = alist_alloc(&vm_contig_alist, 0, size);
1753 if (blk == ALIST_BLOCK_NONE) {
1754 spin_unlock(&vm_contig_spin);
1756 kprintf("vm_page_alloc_contig: %ldk nospace\n",
1757 (size + PAGE_MASK) * (PAGE_SIZE / 1024));
1761 if (high && ((vm_paddr_t)(blk + size) << PAGE_SHIFT) > high) {
1762 alist_free(&vm_contig_alist, blk, size);
1763 spin_unlock(&vm_contig_spin);
1765 kprintf("vm_page_alloc_contig: %ldk high "
1767 (size + PAGE_MASK) * (PAGE_SIZE / 1024),
1772 spin_unlock(&vm_contig_spin);
1773 if (vm_contig_verbose) {
1774 kprintf("vm_page_alloc_contig: %016jx/%ldk\n",
1775 (intmax_t)(vm_paddr_t)blk << PAGE_SHIFT,
1776 (size + PAGE_MASK) * (PAGE_SIZE / 1024));
1779 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT);
1780 if (memattr != VM_MEMATTR_DEFAULT)
1781 for (i = 0;i < size;i++)
1782 pmap_page_set_memattr(&m[i], memattr);
1787 * Free contiguously allocated pages. The pages will be wired but not busy.
1788 * When freeing to the alist we leave them wired and not busy.
1791 vm_page_free_contig(vm_page_t m, unsigned long size)
1793 vm_paddr_t pa = VM_PAGE_TO_PHYS(m);
1794 vm_pindex_t start = pa >> PAGE_SHIFT;
1795 vm_pindex_t pages = (size + PAGE_MASK) >> PAGE_SHIFT;
1797 if (vm_contig_verbose) {
1798 kprintf("vm_page_free_contig: %016jx/%ldk\n",
1799 (intmax_t)pa, size / 1024);
1801 if (pa < vm_low_phys_reserved) {
1802 KKASSERT(pa + size <= vm_low_phys_reserved);
1803 spin_lock(&vm_contig_spin);
1804 alist_free(&vm_contig_alist, start, pages);
1805 spin_unlock(&vm_contig_spin);
1808 vm_page_busy_wait(m, FALSE, "cpgfr");
1809 vm_page_unwire(m, 0);
1820 * Wait for sufficient free memory for nominal heavy memory use kernel
1823 * WARNING! Be sure never to call this in any vm_pageout code path, which
1824 * will trivially deadlock the system.
1827 vm_wait_nominal(void)
1829 while (vm_page_count_min(0))
1834 * Test if vm_wait_nominal() would block.
1837 vm_test_nominal(void)
1839 if (vm_page_count_min(0))
1845 * Block until free pages are available for allocation, called in various
1846 * places before memory allocations.
1848 * The caller may loop if vm_page_count_min() == FALSE so we cannot be
1849 * more generous then that.
1855 * never wait forever
1859 lwkt_gettoken(&vm_token);
1861 if (curthread == pagethread) {
1863 * The pageout daemon itself needs pages, this is bad.
1865 if (vm_page_count_min(0)) {
1866 vm_pageout_pages_needed = 1;
1867 tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo);
1871 * Wakeup the pageout daemon if necessary and wait.
1873 * Do not wait indefinitely for the target to be reached,
1874 * as load might prevent it from being reached any time soon.
1875 * But wait a little to try to slow down page allocations
1876 * and to give more important threads (the pagedaemon)
1877 * allocation priority.
1879 if (vm_page_count_target()) {
1880 if (vm_pages_needed == 0) {
1881 vm_pages_needed = 1;
1882 wakeup(&vm_pages_needed);
1884 ++vm_pages_waiting; /* SMP race ok */
1885 tsleep(&vmstats.v_free_count, 0, "vmwait", timo);
1888 lwkt_reltoken(&vm_token);
1892 * Block until free pages are available for allocation
1894 * Called only from vm_fault so that processes page faulting can be
1898 vm_wait_pfault(void)
1901 * Wakeup the pageout daemon if necessary and wait.
1903 * Do not wait indefinitely for the target to be reached,
1904 * as load might prevent it from being reached any time soon.
1905 * But wait a little to try to slow down page allocations
1906 * and to give more important threads (the pagedaemon)
1907 * allocation priority.
1909 if (vm_page_count_min(0)) {
1910 lwkt_gettoken(&vm_token);
1911 while (vm_page_count_severe()) {
1912 if (vm_page_count_target()) {
1913 if (vm_pages_needed == 0) {
1914 vm_pages_needed = 1;
1915 wakeup(&vm_pages_needed);
1917 ++vm_pages_waiting; /* SMP race ok */
1918 tsleep(&vmstats.v_free_count, 0, "pfault", hz);
1921 lwkt_reltoken(&vm_token);
1926 * Put the specified page on the active list (if appropriate). Ensure
1927 * that act_count is at least ACT_INIT but do not otherwise mess with it.
1929 * The caller should be holding the page busied ? XXX
1930 * This routine may not block.
1933 vm_page_activate(vm_page_t m)
1937 vm_page_spin_lock(m);
1938 if (m->queue - m->pc != PQ_ACTIVE) {
1939 _vm_page_queue_spin_lock(m);
1940 oqueue = _vm_page_rem_queue_spinlocked(m);
1941 /* page is left spinlocked, queue is unlocked */
1943 if (oqueue == PQ_CACHE)
1944 mycpu->gd_cnt.v_reactivated++;
1945 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
1946 if (m->act_count < ACT_INIT)
1947 m->act_count = ACT_INIT;
1948 _vm_page_add_queue_spinlocked(m, PQ_ACTIVE + m->pc, 0);
1950 _vm_page_and_queue_spin_unlock(m);
1951 if (oqueue == PQ_CACHE || oqueue == PQ_FREE)
1952 pagedaemon_wakeup();
1954 if (m->act_count < ACT_INIT)
1955 m->act_count = ACT_INIT;
1956 vm_page_spin_unlock(m);
1961 * Helper routine for vm_page_free_toq() and vm_page_cache(). This
1962 * routine is called when a page has been added to the cache or free
1965 * This routine may not block.
1967 static __inline void
1968 vm_page_free_wakeup(void)
1971 * If the pageout daemon itself needs pages, then tell it that
1972 * there are some free.
1974 if (vm_pageout_pages_needed &&
1975 vmstats.v_cache_count + vmstats.v_free_count >=
1976 vmstats.v_pageout_free_min
1978 vm_pageout_pages_needed = 0;
1979 wakeup(&vm_pageout_pages_needed);
1983 * Wakeup processes that are waiting on memory.
1985 * Generally speaking we want to wakeup stuck processes as soon as
1986 * possible. !vm_page_count_min(0) is the absolute minimum point
1987 * where we can do this. Wait a bit longer to reduce degenerate
1988 * re-blocking (vm_page_free_hysteresis). The target check is just
1989 * to make sure the min-check w/hysteresis does not exceed the
1992 if (vm_pages_waiting) {
1993 if (!vm_page_count_min(vm_page_free_hysteresis) ||
1994 !vm_page_count_target()) {
1995 vm_pages_waiting = 0;
1996 wakeup(&vmstats.v_free_count);
1997 ++mycpu->gd_cnt.v_ppwakeups;
2000 if (!vm_page_count_target()) {
2002 * Plenty of pages are free, wakeup everyone.
2004 vm_pages_waiting = 0;
2005 wakeup(&vmstats.v_free_count);
2006 ++mycpu->gd_cnt.v_ppwakeups;
2007 } else if (!vm_page_count_min(0)) {
2009 * Some pages are free, wakeup someone.
2011 int wcount = vm_pages_waiting;
2014 vm_pages_waiting = wcount;
2015 wakeup_one(&vmstats.v_free_count);
2016 ++mycpu->gd_cnt.v_ppwakeups;
2023 * Returns the given page to the PQ_FREE or PQ_HOLD list and disassociates
2024 * it from its VM object.
2026 * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on
2027 * return (the page will have been freed).
2030 vm_page_free_toq(vm_page_t m)
2032 mycpu->gd_cnt.v_tfree++;
2033 KKASSERT((m->flags & PG_MAPPED) == 0);
2034 KKASSERT(m->flags & PG_BUSY);
2036 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) {
2037 kprintf("vm_page_free: pindex(%lu), busy(%d), "
2038 "PG_BUSY(%d), hold(%d)\n",
2039 (u_long)m->pindex, m->busy,
2040 ((m->flags & PG_BUSY) ? 1 : 0), m->hold_count);
2041 if ((m->queue - m->pc) == PQ_FREE)
2042 panic("vm_page_free: freeing free page");
2044 panic("vm_page_free: freeing busy page");
2048 * Remove from object, spinlock the page and its queues and
2049 * remove from any queue. No queue spinlock will be held
2050 * after this section (because the page was removed from any
2054 vm_page_and_queue_spin_lock(m);
2055 _vm_page_rem_queue_spinlocked(m);
2058 * No further management of fictitious pages occurs beyond object
2059 * and queue removal.
2061 if ((m->flags & PG_FICTITIOUS) != 0) {
2062 vm_page_spin_unlock(m);
2070 if (m->wire_count != 0) {
2071 if (m->wire_count > 1) {
2073 "vm_page_free: invalid wire count (%d), pindex: 0x%lx",
2074 m->wire_count, (long)m->pindex);
2076 panic("vm_page_free: freeing wired page");
2080 * Clear the UNMANAGED flag when freeing an unmanaged page.
2081 * Clear the NEED_COMMIT flag
2083 if (m->flags & PG_UNMANAGED)
2084 vm_page_flag_clear(m, PG_UNMANAGED);
2085 if (m->flags & PG_NEED_COMMIT)
2086 vm_page_flag_clear(m, PG_NEED_COMMIT);
2088 if (m->hold_count != 0) {
2089 vm_page_flag_clear(m, PG_ZERO);
2090 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0);
2092 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0);
2096 * This sequence allows us to clear PG_BUSY while still holding
2097 * its spin lock, which reduces contention vs allocators. We
2098 * must not leave the queue locked or _vm_page_wakeup() may
2101 _vm_page_queue_spin_unlock(m);
2102 if (_vm_page_wakeup(m)) {
2103 vm_page_spin_unlock(m);
2106 vm_page_spin_unlock(m);
2108 vm_page_free_wakeup();
2112 * vm_page_free_fromq_fast()
2114 * Remove a non-zero page from one of the free queues; the page is removed for
2115 * zeroing, so do not issue a wakeup.
2118 vm_page_free_fromq_fast(void)
2124 for (i = 0; i < PQ_L2_SIZE; ++i) {
2125 m = vm_page_list_find(PQ_FREE, qi, FALSE);
2126 /* page is returned spinlocked and removed from its queue */
2128 if (vm_page_busy_try(m, TRUE)) {
2130 * We were unable to busy the page, deactivate
2133 _vm_page_deactivate_locked(m, 0);
2134 vm_page_spin_unlock(m);
2135 } else if (m->flags & PG_ZERO) {
2137 * The page is already PG_ZERO, requeue it and loop
2139 _vm_page_add_queue_spinlocked(m,
2142 vm_page_queue_spin_unlock(m);
2143 if (_vm_page_wakeup(m)) {
2144 vm_page_spin_unlock(m);
2147 vm_page_spin_unlock(m);
2151 * The page is not PG_ZERO'd so return it.
2153 KKASSERT((m->flags & (PG_UNMANAGED |
2154 PG_NEED_COMMIT)) == 0);
2155 KKASSERT(m->hold_count == 0);
2156 KKASSERT(m->wire_count == 0);
2157 vm_page_spin_unlock(m);
2162 qi = (qi + PQ_PRIME2) & PQ_L2_MASK;
2168 * vm_page_unmanage()
2170 * Prevent PV management from being done on the page. The page is
2171 * removed from the paging queues as if it were wired, and as a
2172 * consequence of no longer being managed the pageout daemon will not
2173 * touch it (since there is no way to locate the pte mappings for the
2174 * page). madvise() calls that mess with the pmap will also no longer
2175 * operate on the page.
2177 * Beyond that the page is still reasonably 'normal'. Freeing the page
2178 * will clear the flag.
2180 * This routine is used by OBJT_PHYS objects - objects using unswappable
2181 * physical memory as backing store rather then swap-backed memory and
2182 * will eventually be extended to support 4MB unmanaged physical
2185 * Caller must be holding the page busy.
2188 vm_page_unmanage(vm_page_t m)
2190 KKASSERT(m->flags & PG_BUSY);
2191 if ((m->flags & PG_UNMANAGED) == 0) {
2192 if (m->wire_count == 0)
2195 vm_page_flag_set(m, PG_UNMANAGED);
2199 * Mark this page as wired down by yet another map, removing it from
2200 * paging queues as necessary.
2202 * Caller must be holding the page busy.
2205 vm_page_wire(vm_page_t m)
2208 * Only bump the wire statistics if the page is not already wired,
2209 * and only unqueue the page if it is on some queue (if it is unmanaged
2210 * it is already off the queues). Don't do anything with fictitious
2211 * pages because they are always wired.
2213 KKASSERT(m->flags & PG_BUSY);
2214 if ((m->flags & PG_FICTITIOUS) == 0) {
2215 if (atomic_fetchadd_int(&m->wire_count, 1) == 0) {
2216 if ((m->flags & PG_UNMANAGED) == 0)
2218 atomic_add_int(&vmstats.v_wire_count, 1);
2220 KASSERT(m->wire_count != 0,
2221 ("vm_page_wire: wire_count overflow m=%p", m));
2226 * Release one wiring of this page, potentially enabling it to be paged again.
2228 * Many pages placed on the inactive queue should actually go
2229 * into the cache, but it is difficult to figure out which. What
2230 * we do instead, if the inactive target is well met, is to put
2231 * clean pages at the head of the inactive queue instead of the tail.
2232 * This will cause them to be moved to the cache more quickly and
2233 * if not actively re-referenced, freed more quickly. If we just
2234 * stick these pages at the end of the inactive queue, heavy filesystem
2235 * meta-data accesses can cause an unnecessary paging load on memory bound
2236 * processes. This optimization causes one-time-use metadata to be
2237 * reused more quickly.
2239 * Pages marked PG_NEED_COMMIT are always activated and never placed on
2240 * the inactive queue. This helps the pageout daemon determine memory
2241 * pressure and act on out-of-memory situations more quickly.
2243 * BUT, if we are in a low-memory situation we have no choice but to
2244 * put clean pages on the cache queue.
2246 * A number of routines use vm_page_unwire() to guarantee that the page
2247 * will go into either the inactive or active queues, and will NEVER
2248 * be placed in the cache - for example, just after dirtying a page.
2249 * dirty pages in the cache are not allowed.
2251 * This routine may not block.
2254 vm_page_unwire(vm_page_t m, int activate)
2256 KKASSERT(m->flags & PG_BUSY);
2257 if (m->flags & PG_FICTITIOUS) {
2259 } else if (m->wire_count <= 0) {
2260 panic("vm_page_unwire: invalid wire count: %d", m->wire_count);
2262 if (atomic_fetchadd_int(&m->wire_count, -1) == 1) {
2263 atomic_add_int(&vmstats.v_wire_count, -1);
2264 if (m->flags & PG_UNMANAGED) {
2266 } else if (activate || (m->flags & PG_NEED_COMMIT)) {
2267 vm_page_spin_lock(m);
2268 _vm_page_add_queue_spinlocked(m,
2269 PQ_ACTIVE + m->pc, 0);
2270 _vm_page_and_queue_spin_unlock(m);
2272 vm_page_spin_lock(m);
2273 vm_page_flag_clear(m, PG_WINATCFLS);
2274 _vm_page_add_queue_spinlocked(m,
2275 PQ_INACTIVE + m->pc, 0);
2276 ++vm_swapcache_inactive_heuristic;
2277 _vm_page_and_queue_spin_unlock(m);
2284 * Move the specified page to the inactive queue. If the page has
2285 * any associated swap, the swap is deallocated.
2287 * Normally athead is 0 resulting in LRU operation. athead is set
2288 * to 1 if we want this page to be 'as if it were placed in the cache',
2289 * except without unmapping it from the process address space.
2291 * vm_page's spinlock must be held on entry and will remain held on return.
2292 * This routine may not block.
2295 _vm_page_deactivate_locked(vm_page_t m, int athead)
2300 * Ignore if already inactive.
2302 if (m->queue - m->pc == PQ_INACTIVE)
2304 _vm_page_queue_spin_lock(m);
2305 oqueue = _vm_page_rem_queue_spinlocked(m);
2307 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
2308 if (oqueue == PQ_CACHE)
2309 mycpu->gd_cnt.v_reactivated++;
2310 vm_page_flag_clear(m, PG_WINATCFLS);
2311 _vm_page_add_queue_spinlocked(m, PQ_INACTIVE + m->pc, athead);
2313 ++vm_swapcache_inactive_heuristic;
2315 /* NOTE: PQ_NONE if condition not taken */
2316 _vm_page_queue_spin_unlock(m);
2317 /* leaves vm_page spinlocked */
2321 * Attempt to deactivate a page.
2326 vm_page_deactivate(vm_page_t m)
2328 vm_page_spin_lock(m);
2329 _vm_page_deactivate_locked(m, 0);
2330 vm_page_spin_unlock(m);
2334 vm_page_deactivate_locked(vm_page_t m)
2336 _vm_page_deactivate_locked(m, 0);
2340 * Attempt to move a page to PQ_CACHE.
2342 * Returns 0 on failure, 1 on success
2344 * The page should NOT be busied by the caller. This function will validate
2345 * whether the page can be safely moved to the cache.
2348 vm_page_try_to_cache(vm_page_t m)
2350 vm_page_spin_lock(m);
2351 if (vm_page_busy_try(m, TRUE)) {
2352 vm_page_spin_unlock(m);
2355 if (m->dirty || m->hold_count || m->wire_count ||
2356 (m->flags & (PG_UNMANAGED | PG_NEED_COMMIT))) {
2357 if (_vm_page_wakeup(m)) {
2358 vm_page_spin_unlock(m);
2361 vm_page_spin_unlock(m);
2365 vm_page_spin_unlock(m);
2368 * Page busied by us and no longer spinlocked. Dirty pages cannot
2369 * be moved to the cache.
2371 vm_page_test_dirty(m);
2372 if (m->dirty || (m->flags & PG_NEED_COMMIT)) {
2381 * Attempt to free the page. If we cannot free it, we do nothing.
2382 * 1 is returned on success, 0 on failure.
2387 vm_page_try_to_free(vm_page_t m)
2389 vm_page_spin_lock(m);
2390 if (vm_page_busy_try(m, TRUE)) {
2391 vm_page_spin_unlock(m);
2396 * The page can be in any state, including already being on the free
2397 * queue. Check to see if it really can be freed.
2399 if (m->dirty || /* can't free if it is dirty */
2400 m->hold_count || /* or held (XXX may be wrong) */
2401 m->wire_count || /* or wired */
2402 (m->flags & (PG_UNMANAGED | /* or unmanaged */
2403 PG_NEED_COMMIT)) || /* or needs a commit */
2404 m->queue - m->pc == PQ_FREE || /* already on PQ_FREE */
2405 m->queue - m->pc == PQ_HOLD) { /* already on PQ_HOLD */
2406 if (_vm_page_wakeup(m)) {
2407 vm_page_spin_unlock(m);
2410 vm_page_spin_unlock(m);
2414 vm_page_spin_unlock(m);
2417 * We can probably free the page.
2419 * Page busied by us and no longer spinlocked. Dirty pages will
2420 * not be freed by this function. We have to re-test the
2421 * dirty bit after cleaning out the pmaps.
2423 vm_page_test_dirty(m);
2424 if (m->dirty || (m->flags & PG_NEED_COMMIT)) {
2428 vm_page_protect(m, VM_PROT_NONE);
2429 if (m->dirty || (m->flags & PG_NEED_COMMIT)) {
2440 * Put the specified page onto the page cache queue (if appropriate).
2442 * The page must be busy, and this routine will release the busy and
2443 * possibly even free the page.
2446 vm_page_cache(vm_page_t m)
2448 if ((m->flags & (PG_UNMANAGED | PG_NEED_COMMIT)) ||
2449 m->busy || m->wire_count || m->hold_count) {
2450 kprintf("vm_page_cache: attempting to cache busy/held page\n");
2456 * Already in the cache (and thus not mapped)
2458 if ((m->queue - m->pc) == PQ_CACHE) {
2459 KKASSERT((m->flags & PG_MAPPED) == 0);
2465 * Caller is required to test m->dirty, but note that the act of
2466 * removing the page from its maps can cause it to become dirty
2467 * on an SMP system due to another cpu running in usermode.
2470 panic("vm_page_cache: caching a dirty page, pindex: %ld",
2475 * Remove all pmaps and indicate that the page is not
2476 * writeable or mapped. Our vm_page_protect() call may
2477 * have blocked (especially w/ VM_PROT_NONE), so recheck
2480 vm_page_protect(m, VM_PROT_NONE);
2481 if ((m->flags & (PG_UNMANAGED | PG_MAPPED)) ||
2482 m->busy || m->wire_count || m->hold_count) {
2484 } else if (m->dirty || (m->flags & PG_NEED_COMMIT)) {
2485 vm_page_deactivate(m);
2488 _vm_page_and_queue_spin_lock(m);
2489 _vm_page_rem_queue_spinlocked(m);
2490 _vm_page_add_queue_spinlocked(m, PQ_CACHE + m->pc, 0);
2491 _vm_page_queue_spin_unlock(m);
2492 if (_vm_page_wakeup(m)) {
2493 vm_page_spin_unlock(m);
2496 vm_page_spin_unlock(m);
2498 vm_page_free_wakeup();
2503 * vm_page_dontneed()
2505 * Cache, deactivate, or do nothing as appropriate. This routine
2506 * is typically used by madvise() MADV_DONTNEED.
2508 * Generally speaking we want to move the page into the cache so
2509 * it gets reused quickly. However, this can result in a silly syndrome
2510 * due to the page recycling too quickly. Small objects will not be
2511 * fully cached. On the otherhand, if we move the page to the inactive
2512 * queue we wind up with a problem whereby very large objects
2513 * unnecessarily blow away our inactive and cache queues.
2515 * The solution is to move the pages based on a fixed weighting. We
2516 * either leave them alone, deactivate them, or move them to the cache,
2517 * where moving them to the cache has the highest weighting.
2518 * By forcing some pages into other queues we eventually force the
2519 * system to balance the queues, potentially recovering other unrelated
2520 * space from active. The idea is to not force this to happen too
2523 * The page must be busied.
2526 vm_page_dontneed(vm_page_t m)
2528 static int dnweight;
2535 * occassionally leave the page alone
2537 if ((dnw & 0x01F0) == 0 ||
2538 m->queue - m->pc == PQ_INACTIVE ||
2539 m->queue - m->pc == PQ_CACHE
2541 if (m->act_count >= ACT_INIT)
2547 * If vm_page_dontneed() is inactivating a page, it must clear
2548 * the referenced flag; otherwise the pagedaemon will see references
2549 * on the page in the inactive queue and reactivate it. Until the
2550 * page can move to the cache queue, madvise's job is not done.
2552 vm_page_flag_clear(m, PG_REFERENCED);
2553 pmap_clear_reference(m);
2556 vm_page_test_dirty(m);
2558 if (m->dirty || (dnw & 0x0070) == 0) {
2560 * Deactivate the page 3 times out of 32.
2565 * Cache the page 28 times out of every 32. Note that
2566 * the page is deactivated instead of cached, but placed
2567 * at the head of the queue instead of the tail.
2571 vm_page_spin_lock(m);
2572 _vm_page_deactivate_locked(m, head);
2573 vm_page_spin_unlock(m);
2577 * These routines manipulate the 'soft busy' count for a page. A soft busy
2578 * is almost like PG_BUSY except that it allows certain compatible operations
2579 * to occur on the page while it is busy. For example, a page undergoing a
2580 * write can still be mapped read-only.
2582 * Because vm_pages can overlap buffers m->busy can be > 1. m->busy is only
2583 * adjusted while the vm_page is PG_BUSY so the flash will occur when the
2584 * busy bit is cleared.
2587 vm_page_io_start(vm_page_t m)
2589 KASSERT(m->flags & PG_BUSY, ("vm_page_io_start: page not busy!!!"));
2590 atomic_add_char(&m->busy, 1);
2591 vm_page_flag_set(m, PG_SBUSY);
2595 vm_page_io_finish(vm_page_t m)
2597 KASSERT(m->flags & PG_BUSY, ("vm_page_io_finish: page not busy!!!"));
2598 atomic_subtract_char(&m->busy, 1);
2600 vm_page_flag_clear(m, PG_SBUSY);
2604 * Indicate that a clean VM page requires a filesystem commit and cannot
2605 * be reused. Used by tmpfs.
2608 vm_page_need_commit(vm_page_t m)
2610 vm_page_flag_set(m, PG_NEED_COMMIT);
2611 vm_object_set_writeable_dirty(m->object);
2615 vm_page_clear_commit(vm_page_t m)
2617 vm_page_flag_clear(m, PG_NEED_COMMIT);
2621 * Grab a page, blocking if it is busy and allocating a page if necessary.
2622 * A busy page is returned or NULL. The page may or may not be valid and
2623 * might not be on a queue (the caller is responsible for the disposition of
2626 * If VM_ALLOC_ZERO is specified and the grab must allocate a new page, the
2627 * page will be zero'd and marked valid.
2629 * If VM_ALLOC_FORCE_ZERO is specified the page will be zero'd and marked
2630 * valid even if it already exists.
2632 * If VM_ALLOC_RETRY is specified this routine will never return NULL. Also
2633 * note that VM_ALLOC_NORMAL must be specified if VM_ALLOC_RETRY is specified.
2634 * VM_ALLOC_NULL_OK is implied when VM_ALLOC_RETRY is specified.
2636 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is
2637 * always returned if we had blocked.
2639 * This routine may not be called from an interrupt.
2641 * PG_ZERO is *ALWAYS* cleared by this routine.
2643 * No other requirements.
2646 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
2652 KKASSERT(allocflags &
2653 (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
2654 vm_object_hold_shared(object);
2656 m = vm_page_lookup_busy_try(object, pindex, TRUE, &error);
2658 vm_page_sleep_busy(m, TRUE, "pgrbwt");
2659 if ((allocflags & VM_ALLOC_RETRY) == 0) {
2664 } else if (m == NULL) {
2666 vm_object_upgrade(object);
2669 if (allocflags & VM_ALLOC_RETRY)
2670 allocflags |= VM_ALLOC_NULL_OK;
2671 m = vm_page_alloc(object, pindex,
2672 allocflags & ~VM_ALLOC_RETRY);
2676 if ((allocflags & VM_ALLOC_RETRY) == 0)
2685 * If VM_ALLOC_ZERO an invalid page will be zero'd and set valid.
2687 * If VM_ALLOC_FORCE_ZERO the page is unconditionally zero'd and set
2688 * valid even if already valid.
2690 if (m->valid == 0) {
2691 if (allocflags & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) {
2692 if ((m->flags & PG_ZERO) == 0)
2693 pmap_zero_page(VM_PAGE_TO_PHYS(m));
2694 m->valid = VM_PAGE_BITS_ALL;
2696 } else if (allocflags & VM_ALLOC_FORCE_ZERO) {
2697 pmap_zero_page(VM_PAGE_TO_PHYS(m));
2698 m->valid = VM_PAGE_BITS_ALL;
2700 vm_page_flag_clear(m, PG_ZERO);
2702 vm_object_drop(object);
2707 * Mapping function for valid bits or for dirty bits in
2708 * a page. May not block.
2710 * Inputs are required to range within a page.
2716 vm_page_bits(int base, int size)
2722 base + size <= PAGE_SIZE,
2723 ("vm_page_bits: illegal base/size %d/%d", base, size)
2726 if (size == 0) /* handle degenerate case */
2729 first_bit = base >> DEV_BSHIFT;
2730 last_bit = (base + size - 1) >> DEV_BSHIFT;
2732 return ((2 << last_bit) - (1 << first_bit));
2736 * Sets portions of a page valid and clean. The arguments are expected
2737 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
2738 * of any partial chunks touched by the range. The invalid portion of
2739 * such chunks will be zero'd.
2741 * NOTE: When truncating a buffer vnode_pager_setsize() will automatically
2742 * align base to DEV_BSIZE so as not to mark clean a partially
2743 * truncated device block. Otherwise the dirty page status might be
2746 * This routine may not block.
2748 * (base + size) must be less then or equal to PAGE_SIZE.
2751 _vm_page_zero_valid(vm_page_t m, int base, int size)
2756 if (size == 0) /* handle degenerate case */
2760 * If the base is not DEV_BSIZE aligned and the valid
2761 * bit is clear, we have to zero out a portion of the
2765 if ((frag = base & ~(DEV_BSIZE - 1)) != base &&
2766 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0
2768 pmap_zero_page_area(
2776 * If the ending offset is not DEV_BSIZE aligned and the
2777 * valid bit is clear, we have to zero out a portion of
2781 endoff = base + size;
2783 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff &&
2784 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0
2786 pmap_zero_page_area(
2789 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))
2795 * Set valid, clear dirty bits. If validating the entire
2796 * page we can safely clear the pmap modify bit. We also
2797 * use this opportunity to clear the PG_NOSYNC flag. If a process
2798 * takes a write fault on a MAP_NOSYNC memory area the flag will
2801 * We set valid bits inclusive of any overlap, but we can only
2802 * clear dirty bits for DEV_BSIZE chunks that are fully within
2805 * Page must be busied?
2806 * No other requirements.
2809 vm_page_set_valid(vm_page_t m, int base, int size)
2811 _vm_page_zero_valid(m, base, size);
2812 m->valid |= vm_page_bits(base, size);
2817 * Set valid bits and clear dirty bits.
2819 * NOTE: This function does not clear the pmap modified bit.
2820 * Also note that e.g. NFS may use a byte-granular base
2823 * WARNING: Page must be busied? But vfs_clean_one_page() will call
2824 * this without necessarily busying the page (via bdwrite()).
2825 * So for now vm_token must also be held.
2827 * No other requirements.
2830 vm_page_set_validclean(vm_page_t m, int base, int size)
2834 _vm_page_zero_valid(m, base, size);
2835 pagebits = vm_page_bits(base, size);
2836 m->valid |= pagebits;
2837 m->dirty &= ~pagebits;
2838 if (base == 0 && size == PAGE_SIZE) {
2839 /*pmap_clear_modify(m);*/
2840 vm_page_flag_clear(m, PG_NOSYNC);
2845 * Set valid & dirty. Used by buwrite()
2847 * WARNING: Page must be busied? But vfs_dirty_one_page() will
2848 * call this function in buwrite() so for now vm_token must
2851 * No other requirements.
2854 vm_page_set_validdirty(vm_page_t m, int base, int size)
2858 pagebits = vm_page_bits(base, size);
2859 m->valid |= pagebits;
2860 m->dirty |= pagebits;
2862 vm_object_set_writeable_dirty(m->object);
2868 * NOTE: This function does not clear the pmap modified bit.
2869 * Also note that e.g. NFS may use a byte-granular base
2872 * Page must be busied?
2873 * No other requirements.
2876 vm_page_clear_dirty(vm_page_t m, int base, int size)
2878 m->dirty &= ~vm_page_bits(base, size);
2879 if (base == 0 && size == PAGE_SIZE) {
2880 /*pmap_clear_modify(m);*/
2881 vm_page_flag_clear(m, PG_NOSYNC);
2886 * Make the page all-dirty.
2888 * Also make sure the related object and vnode reflect the fact that the
2889 * object may now contain a dirty page.
2891 * Page must be busied?
2892 * No other requirements.
2895 vm_page_dirty(vm_page_t m)
2898 int pqtype = m->queue - m->pc;
2900 KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE,
2901 ("vm_page_dirty: page in free/cache queue!"));
2902 if (m->dirty != VM_PAGE_BITS_ALL) {
2903 m->dirty = VM_PAGE_BITS_ALL;
2905 vm_object_set_writeable_dirty(m->object);
2910 * Invalidates DEV_BSIZE'd chunks within a page. Both the
2911 * valid and dirty bits for the effected areas are cleared.
2913 * Page must be busied?
2915 * No other requirements.
2918 vm_page_set_invalid(vm_page_t m, int base, int size)
2922 bits = vm_page_bits(base, size);
2925 m->object->generation++;
2929 * The kernel assumes that the invalid portions of a page contain
2930 * garbage, but such pages can be mapped into memory by user code.
2931 * When this occurs, we must zero out the non-valid portions of the
2932 * page so user code sees what it expects.
2934 * Pages are most often semi-valid when the end of a file is mapped
2935 * into memory and the file's size is not page aligned.
2937 * Page must be busied?
2938 * No other requirements.
2941 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
2947 * Scan the valid bits looking for invalid sections that
2948 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the
2949 * valid bit may be set ) have already been zerod by
2950 * vm_page_set_validclean().
2952 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
2953 if (i == (PAGE_SIZE / DEV_BSIZE) ||
2954 (m->valid & (1 << i))
2957 pmap_zero_page_area(
2960 (i - b) << DEV_BSHIFT
2968 * setvalid is TRUE when we can safely set the zero'd areas
2969 * as being valid. We can do this if there are no cache consistency
2970 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS.
2973 m->valid = VM_PAGE_BITS_ALL;
2977 * Is a (partial) page valid? Note that the case where size == 0
2978 * will return FALSE in the degenerate case where the page is entirely
2979 * invalid, and TRUE otherwise.
2982 * No other requirements.
2985 vm_page_is_valid(vm_page_t m, int base, int size)
2987 int bits = vm_page_bits(base, size);
2989 if (m->valid && ((m->valid & bits) == bits))
2996 * update dirty bits from pmap/mmu. May not block.
2998 * Caller must hold the page busy
3001 vm_page_test_dirty(vm_page_t m)
3003 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) {
3009 * Register an action, associating it with its vm_page
3012 vm_page_register_action(vm_page_action_t action, vm_page_event_t event)
3014 struct vm_page_action_list *list;
3017 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK;
3018 list = &action_list[hv];
3020 lwkt_gettoken(&vm_token);
3021 vm_page_flag_set(action->m, PG_ACTIONLIST);
3022 action->event = event;
3023 LIST_INSERT_HEAD(list, action, entry);
3024 lwkt_reltoken(&vm_token);
3028 * Unregister an action, disassociating it from its related vm_page
3031 vm_page_unregister_action(vm_page_action_t action)
3033 struct vm_page_action_list *list;
3036 lwkt_gettoken(&vm_token);
3037 if (action->event != VMEVENT_NONE) {
3038 action->event = VMEVENT_NONE;
3039 LIST_REMOVE(action, entry);
3041 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK;
3042 list = &action_list[hv];
3043 if (LIST_EMPTY(list))
3044 vm_page_flag_clear(action->m, PG_ACTIONLIST);
3046 lwkt_reltoken(&vm_token);
3050 * Issue an event on a VM page. Corresponding action structures are
3051 * removed from the page's list and called.
3053 * If the vm_page has no more pending action events we clear its
3054 * PG_ACTIONLIST flag.
3057 vm_page_event_internal(vm_page_t m, vm_page_event_t event)
3059 struct vm_page_action_list *list;
3060 struct vm_page_action *scan;
3061 struct vm_page_action *next;
3065 hv = (int)((intptr_t)m >> 8) & VMACTION_HMASK;
3066 list = &action_list[hv];
3069 lwkt_gettoken(&vm_token);
3070 LIST_FOREACH_MUTABLE(scan, list, entry, next) {
3072 if (scan->event == event) {
3073 scan->event = VMEVENT_NONE;
3074 LIST_REMOVE(scan, entry);
3075 scan->func(m, scan);
3083 vm_page_flag_clear(m, PG_ACTIONLIST);
3084 lwkt_reltoken(&vm_token);
3087 #include "opt_ddb.h"
3089 #include <sys/kernel.h>
3091 #include <ddb/ddb.h>
3093 DB_SHOW_COMMAND(page, vm_page_print_page_info)
3095 db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count);
3096 db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count);
3097 db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count);
3098 db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count);
3099 db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count);
3100 db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved);
3101 db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min);
3102 db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target);
3103 db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min);
3104 db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target);
3107 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
3110 db_printf("PQ_FREE:");
3111 for(i=0;i<PQ_L2_SIZE;i++) {
3112 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt);
3116 db_printf("PQ_CACHE:");
3117 for(i=0;i<PQ_L2_SIZE;i++) {
3118 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt);
3122 db_printf("PQ_ACTIVE:");
3123 for(i=0;i<PQ_L2_SIZE;i++) {
3124 db_printf(" %d", vm_page_queues[PQ_ACTIVE + i].lcnt);
3128 db_printf("PQ_INACTIVE:");
3129 for(i=0;i<PQ_L2_SIZE;i++) {
3130 db_printf(" %d", vm_page_queues[PQ_INACTIVE + i].lcnt);