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 * 4. 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>
95 #include <vm/vm_page2.h>
96 #include <sys/spinlock2.h>
98 #define VMACTION_HSIZE 256
99 #define VMACTION_HMASK (VMACTION_HSIZE - 1)
101 static void vm_page_queue_init(void);
102 static void vm_page_free_wakeup(void);
103 static vm_page_t vm_page_select_cache(u_short pg_color);
104 static vm_page_t _vm_page_list_find2(int basequeue, int index);
105 static void _vm_page_deactivate_locked(vm_page_t m, int athead);
108 * Array of tailq lists
110 __cachealign struct vpgqueues vm_page_queues[PQ_COUNT];
112 LIST_HEAD(vm_page_action_list, vm_page_action);
113 struct vm_page_action_list action_list[VMACTION_HSIZE];
114 static volatile int vm_pages_waiting;
116 static struct alist vm_contig_alist;
117 static struct almeta vm_contig_ameta[ALIST_RECORDS_65536];
118 static struct spinlock vm_contig_spin = SPINLOCK_INITIALIZER(&vm_contig_spin);
120 static u_long vm_dma_reserved = 0;
121 TUNABLE_ULONG("vm.dma_reserved", &vm_dma_reserved);
122 SYSCTL_ULONG(_vm, OID_AUTO, dma_reserved, CTLFLAG_RD, &vm_dma_reserved, 0,
123 "Memory reserved for DMA");
124 SYSCTL_UINT(_vm, OID_AUTO, dma_free_pages, CTLFLAG_RD,
125 &vm_contig_alist.bl_free, 0, "Memory reserved for DMA");
127 RB_GENERATE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare,
128 vm_pindex_t, pindex);
131 vm_page_queue_init(void)
135 for (i = 0; i < PQ_L2_SIZE; i++)
136 vm_page_queues[PQ_FREE+i].cnt = &vmstats.v_free_count;
137 for (i = 0; i < PQ_L2_SIZE; i++)
138 vm_page_queues[PQ_CACHE+i].cnt = &vmstats.v_cache_count;
139 for (i = 0; i < PQ_L2_SIZE; i++)
140 vm_page_queues[PQ_INACTIVE+i].cnt = &vmstats.v_inactive_count;
141 for (i = 0; i < PQ_L2_SIZE; i++)
142 vm_page_queues[PQ_ACTIVE+i].cnt = &vmstats.v_active_count;
143 for (i = 0; i < PQ_L2_SIZE; i++)
144 vm_page_queues[PQ_HOLD+i].cnt = &vmstats.v_active_count;
145 /* PQ_NONE has no queue */
147 for (i = 0; i < PQ_COUNT; i++) {
148 TAILQ_INIT(&vm_page_queues[i].pl);
149 spin_init(&vm_page_queues[i].spin);
152 for (i = 0; i < VMACTION_HSIZE; i++)
153 LIST_INIT(&action_list[i]);
157 * note: place in initialized data section? Is this necessary?
160 int vm_page_array_size = 0;
161 int vm_page_zero_count = 0;
162 vm_page_t vm_page_array = NULL;
163 vm_paddr_t vm_low_phys_reserved;
168 * Sets the page size, perhaps based upon the memory size.
169 * Must be called before any use of page-size dependent functions.
172 vm_set_page_size(void)
174 if (vmstats.v_page_size == 0)
175 vmstats.v_page_size = PAGE_SIZE;
176 if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0)
177 panic("vm_set_page_size: page size not a power of two");
183 * Add a new page to the freelist for use by the system. New pages
184 * are added to both the head and tail of the associated free page
185 * queue in a bottom-up fashion, so both zero'd and non-zero'd page
186 * requests pull 'recent' adds (higher physical addresses) first.
188 * Beware that the page zeroing daemon will also be running soon after
189 * boot, moving pages from the head to the tail of the PQ_FREE queues.
191 * Must be called in a critical section.
194 vm_add_new_page(vm_paddr_t pa)
196 struct vpgqueues *vpq;
199 m = PHYS_TO_VM_PAGE(pa);
202 m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK;
205 * Twist for cpu localization in addition to page coloring, so
206 * different cpus selecting by m->queue get different page colors.
208 m->pc ^= ((pa >> PAGE_SHIFT) / PQ_L2_SIZE) & PQ_L2_MASK;
209 m->pc ^= ((pa >> PAGE_SHIFT) / (PQ_L2_SIZE * PQ_L2_SIZE)) & PQ_L2_MASK;
212 * Reserve a certain number of contiguous low memory pages for
213 * contigmalloc() to use.
215 if (pa < vm_low_phys_reserved) {
216 atomic_add_int(&vmstats.v_page_count, 1);
217 atomic_add_int(&vmstats.v_dma_pages, 1);
220 atomic_add_int(&vmstats.v_wire_count, 1);
221 alist_free(&vm_contig_alist, pa >> PAGE_SHIFT, 1);
228 m->queue = m->pc + PQ_FREE;
229 KKASSERT(m->dirty == 0);
231 atomic_add_int(&vmstats.v_page_count, 1);
232 atomic_add_int(&vmstats.v_free_count, 1);
233 vpq = &vm_page_queues[m->queue];
234 if ((vpq->flipflop & 15) == 0) {
235 pmap_zero_page(VM_PAGE_TO_PHYS(m));
237 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq);
238 atomic_add_int(&vm_page_zero_count, 1);
240 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq);
249 * Initializes the resident memory module.
251 * Preallocates memory for critical VM structures and arrays prior to
252 * kernel_map becoming available.
254 * Memory is allocated from (virtual2_start, virtual2_end) if available,
255 * otherwise memory is allocated from (virtual_start, virtual_end).
257 * On x86-64 (virtual_start, virtual_end) is only 2GB and may not be
258 * large enough to hold vm_page_array & other structures for machines with
259 * large amounts of ram, so we want to use virtual2* when available.
262 vm_page_startup(void)
264 vm_offset_t vaddr = virtual2_start ? virtual2_start : virtual_start;
267 vm_paddr_t page_range;
274 vm_paddr_t biggestone, biggestsize;
281 vaddr = round_page(vaddr);
283 for (i = 0; phys_avail[i + 1]; i += 2) {
284 phys_avail[i] = round_page64(phys_avail[i]);
285 phys_avail[i + 1] = trunc_page64(phys_avail[i + 1]);
288 for (i = 0; phys_avail[i + 1]; i += 2) {
289 vm_paddr_t size = phys_avail[i + 1] - phys_avail[i];
291 if (size > biggestsize) {
299 end = phys_avail[biggestone+1];
300 end = trunc_page(end);
303 * Initialize the queue headers for the free queue, the active queue
304 * and the inactive queue.
306 vm_page_queue_init();
308 #if !defined(_KERNEL_VIRTUAL)
310 * VKERNELs don't support minidumps and as such don't need
313 * Allocate a bitmap to indicate that a random physical page
314 * needs to be included in a minidump.
316 * The amd64 port needs this to indicate which direct map pages
317 * need to be dumped, via calls to dump_add_page()/dump_drop_page().
319 * However, i386 still needs this workspace internally within the
320 * minidump code. In theory, they are not needed on i386, but are
321 * included should the sf_buf code decide to use them.
323 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE;
324 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY);
325 end -= vm_page_dump_size;
326 vm_page_dump = (void *)pmap_map(&vaddr, end, end + vm_page_dump_size,
327 VM_PROT_READ | VM_PROT_WRITE);
328 bzero((void *)vm_page_dump, vm_page_dump_size);
331 * Compute the number of pages of memory that will be available for
332 * use (taking into account the overhead of a page structure per
335 first_page = phys_avail[0] / PAGE_SIZE;
336 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page;
337 npages = (total - (page_range * sizeof(struct vm_page))) / PAGE_SIZE;
339 #ifndef _KERNEL_VIRTUAL
341 * (only applies to real kernels)
343 * Initialize the contiguous reserve map. We initially reserve up
344 * to 1/4 available physical memory or 65536 pages (~256MB), whichever
347 * Once device initialization is complete we return most of the
348 * reserved memory back to the normal page queues but leave some
349 * in reserve for things like usb attachments.
351 vm_low_phys_reserved = (vm_paddr_t)65536 << PAGE_SHIFT;
352 if (vm_low_phys_reserved > total / 4)
353 vm_low_phys_reserved = total / 4;
354 if (vm_dma_reserved == 0) {
355 vm_dma_reserved = 16 * 1024 * 1024; /* 16MB */
356 if (vm_dma_reserved > total / 16)
357 vm_dma_reserved = total / 16;
360 alist_init(&vm_contig_alist, 65536, vm_contig_ameta,
361 ALIST_RECORDS_65536);
364 * Initialize the mem entry structures now, and put them in the free
367 new_end = trunc_page(end - page_range * sizeof(struct vm_page));
368 mapped = pmap_map(&vaddr, new_end, end, VM_PROT_READ | VM_PROT_WRITE);
369 vm_page_array = (vm_page_t)mapped;
371 #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL)
373 * since pmap_map on amd64 returns stuff out of a direct-map region,
374 * we have to manually add these pages to the minidump tracking so
375 * that they can be dumped, including the vm_page_array.
377 for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE)
382 * Clear all of the page structures
384 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page));
385 vm_page_array_size = page_range;
388 * Construct the free queue(s) in ascending order (by physical
389 * address) so that the first 16MB of physical memory is allocated
390 * last rather than first. On large-memory machines, this avoids
391 * the exhaustion of low physical memory before isa_dmainit has run.
393 vmstats.v_page_count = 0;
394 vmstats.v_free_count = 0;
395 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) {
400 last_pa = phys_avail[i + 1];
401 while (pa < last_pa && npages-- > 0) {
407 virtual2_start = vaddr;
409 virtual_start = vaddr;
413 * We tended to reserve a ton of memory for contigmalloc(). Now that most
414 * drivers have initialized we want to return most the remaining free
415 * reserve back to the VM page queues so they can be used for normal
418 * We leave vm_dma_reserved bytes worth of free pages in the reserve pool.
421 vm_page_startup_finish(void *dummy __unused)
430 spin_lock(&vm_contig_spin);
432 bfree = alist_free_info(&vm_contig_alist, &blk, &count);
433 if (bfree <= vm_dma_reserved / PAGE_SIZE)
439 * Figure out how much of the initial reserve we have to
440 * free in order to reach our target.
442 bfree -= vm_dma_reserved / PAGE_SIZE;
444 blk += count - bfree;
449 * Calculate the nearest power of 2 <= count.
451 for (xcount = 1; xcount <= count; xcount <<= 1)
454 blk += count - xcount;
458 * Allocate the pages from the alist, then free them to
459 * the normal VM page queues.
461 * Pages allocated from the alist are wired. We have to
462 * busy, unwire, and free them. We must also adjust
463 * vm_low_phys_reserved before freeing any pages to prevent
466 rblk = alist_alloc(&vm_contig_alist, blk, count);
468 kprintf("vm_page_startup_finish: Unable to return "
469 "dma space @0x%08x/%d -> 0x%08x\n",
473 atomic_add_int(&vmstats.v_dma_pages, -count);
474 spin_unlock(&vm_contig_spin);
476 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT);
477 vm_low_phys_reserved = VM_PAGE_TO_PHYS(m);
479 vm_page_busy_wait(m, FALSE, "cpgfr");
480 vm_page_unwire(m, 0);
485 spin_lock(&vm_contig_spin);
487 spin_unlock(&vm_contig_spin);
490 * Print out how much DMA space drivers have already allocated and
491 * how much is left over.
493 kprintf("DMA space used: %jdk, remaining available: %jdk\n",
494 (intmax_t)(vmstats.v_dma_pages - vm_contig_alist.bl_free) *
496 (intmax_t)vm_contig_alist.bl_free * (PAGE_SIZE / 1024));
498 SYSINIT(vm_pgend, SI_SUB_PROC0_POST, SI_ORDER_ANY,
499 vm_page_startup_finish, NULL)
503 * Scan comparison function for Red-Black tree scans. An inclusive
504 * (start,end) is expected. Other fields are not used.
507 rb_vm_page_scancmp(struct vm_page *p, void *data)
509 struct rb_vm_page_scan_info *info = data;
511 if (p->pindex < info->start_pindex)
513 if (p->pindex > info->end_pindex)
519 rb_vm_page_compare(struct vm_page *p1, struct vm_page *p2)
521 if (p1->pindex < p2->pindex)
523 if (p1->pindex > p2->pindex)
529 * Each page queue has its own spin lock, which is fairly optimal for
530 * allocating and freeing pages at least.
532 * The caller must hold the vm_page_spin_lock() before locking a vm_page's
533 * queue spinlock via this function. Also note that m->queue cannot change
534 * unless both the page and queue are locked.
538 _vm_page_queue_spin_lock(vm_page_t m)
543 if (queue != PQ_NONE) {
544 spin_lock(&vm_page_queues[queue].spin);
545 KKASSERT(queue == m->queue);
551 _vm_page_queue_spin_unlock(vm_page_t m)
557 if (queue != PQ_NONE)
558 spin_unlock(&vm_page_queues[queue].spin);
563 _vm_page_queues_spin_lock(u_short queue)
566 if (queue != PQ_NONE)
567 spin_lock(&vm_page_queues[queue].spin);
573 _vm_page_queues_spin_unlock(u_short queue)
576 if (queue != PQ_NONE)
577 spin_unlock(&vm_page_queues[queue].spin);
581 vm_page_queue_spin_lock(vm_page_t m)
583 _vm_page_queue_spin_lock(m);
587 vm_page_queues_spin_lock(u_short queue)
589 _vm_page_queues_spin_lock(queue);
593 vm_page_queue_spin_unlock(vm_page_t m)
595 _vm_page_queue_spin_unlock(m);
599 vm_page_queues_spin_unlock(u_short queue)
601 _vm_page_queues_spin_unlock(queue);
605 * This locks the specified vm_page and its queue in the proper order
606 * (page first, then queue). The queue may change so the caller must
611 _vm_page_and_queue_spin_lock(vm_page_t m)
613 vm_page_spin_lock(m);
614 _vm_page_queue_spin_lock(m);
619 _vm_page_and_queue_spin_unlock(vm_page_t m)
621 _vm_page_queues_spin_unlock(m->queue);
622 vm_page_spin_unlock(m);
626 vm_page_and_queue_spin_unlock(vm_page_t m)
628 _vm_page_and_queue_spin_unlock(m);
632 vm_page_and_queue_spin_lock(vm_page_t m)
634 _vm_page_and_queue_spin_lock(m);
638 * Helper function removes vm_page from its current queue.
639 * Returns the base queue the page used to be on.
641 * The vm_page and the queue must be spinlocked.
642 * This function will unlock the queue but leave the page spinlocked.
644 static __inline u_short
645 _vm_page_rem_queue_spinlocked(vm_page_t m)
647 struct vpgqueues *pq;
651 if (queue != PQ_NONE) {
652 pq = &vm_page_queues[queue];
653 TAILQ_REMOVE(&pq->pl, m, pageq);
654 atomic_add_int(pq->cnt, -1);
657 vm_page_queues_spin_unlock(queue);
658 if ((queue - m->pc) == PQ_FREE && (m->flags & PG_ZERO))
659 atomic_subtract_int(&vm_page_zero_count, 1);
660 if ((queue - m->pc) == PQ_CACHE || (queue - m->pc) == PQ_FREE)
661 return (queue - m->pc);
667 * Helper function places the vm_page on the specified queue.
669 * The vm_page must be spinlocked.
670 * This function will return with both the page and the queue locked.
673 _vm_page_add_queue_spinlocked(vm_page_t m, u_short queue, int athead)
675 struct vpgqueues *pq;
677 KKASSERT(m->queue == PQ_NONE);
679 if (queue != PQ_NONE) {
680 vm_page_queues_spin_lock(queue);
681 pq = &vm_page_queues[queue];
683 atomic_add_int(pq->cnt, 1);
687 * Put zero'd pages on the end ( where we look for zero'd pages
688 * first ) and non-zerod pages at the head.
690 if (queue - m->pc == PQ_FREE) {
691 if (m->flags & PG_ZERO) {
692 TAILQ_INSERT_TAIL(&pq->pl, m, pageq);
693 atomic_add_int(&vm_page_zero_count, 1);
695 TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
698 TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
700 TAILQ_INSERT_TAIL(&pq->pl, m, pageq);
702 /* leave the queue spinlocked */
707 * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE)
708 * m->busy is zero. Returns TRUE if it had to sleep, FALSE if we
709 * did not. Only one sleep call will be made before returning.
711 * This function does NOT busy the page and on return the page is not
712 * guaranteed to be available.
715 vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg)
723 if ((flags & PG_BUSY) == 0 &&
724 (also_m_busy == 0 || (flags & PG_SBUSY) == 0)) {
727 tsleep_interlock(m, 0);
728 if (atomic_cmpset_int(&m->flags, flags,
729 flags | PG_WANTED | PG_REFERENCED)) {
730 tsleep(m, PINTERLOCKED, msg, 0);
737 * Wait until PG_BUSY can be set, then set it. If also_m_busy is TRUE we
738 * also wait for m->busy to become 0 before setting PG_BUSY.
741 VM_PAGE_DEBUG_EXT(vm_page_busy_wait)(vm_page_t m,
742 int also_m_busy, const char *msg
750 if (flags & PG_BUSY) {
751 tsleep_interlock(m, 0);
752 if (atomic_cmpset_int(&m->flags, flags,
753 flags | PG_WANTED | PG_REFERENCED)) {
754 tsleep(m, PINTERLOCKED, msg, 0);
756 } else if (also_m_busy && (flags & PG_SBUSY)) {
757 tsleep_interlock(m, 0);
758 if (atomic_cmpset_int(&m->flags, flags,
759 flags | PG_WANTED | PG_REFERENCED)) {
760 tsleep(m, PINTERLOCKED, msg, 0);
763 if (atomic_cmpset_int(&m->flags, flags,
767 m->busy_line = lineno;
776 * Attempt to set PG_BUSY. If also_m_busy is TRUE we only succeed if m->busy
779 * Returns non-zero on failure.
782 VM_PAGE_DEBUG_EXT(vm_page_busy_try)(vm_page_t m, int also_m_busy
792 if (also_m_busy && (flags & PG_SBUSY))
794 if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) {
797 m->busy_line = lineno;
805 * Clear the PG_BUSY flag and return non-zero to indicate to the caller
806 * that a wakeup() should be performed.
808 * The vm_page must be spinlocked and will remain spinlocked on return.
809 * The related queue must NOT be spinlocked (which could deadlock us).
815 _vm_page_wakeup(vm_page_t m)
822 if (atomic_cmpset_int(&m->flags, flags,
823 flags & ~(PG_BUSY | PG_WANTED))) {
827 return(flags & PG_WANTED);
831 * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This
832 * is typically the last call you make on a page before moving onto
836 vm_page_wakeup(vm_page_t m)
838 KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!"));
839 vm_page_spin_lock(m);
840 if (_vm_page_wakeup(m)) {
841 vm_page_spin_unlock(m);
844 vm_page_spin_unlock(m);
849 * Holding a page keeps it from being reused. Other parts of the system
850 * can still disassociate the page from its current object and free it, or
851 * perform read or write I/O on it and/or otherwise manipulate the page,
852 * but if the page is held the VM system will leave the page and its data
853 * intact and not reuse the page for other purposes until the last hold
854 * reference is released. (see vm_page_wire() if you want to prevent the
855 * page from being disassociated from its object too).
857 * The caller must still validate the contents of the page and, if necessary,
858 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete
859 * before manipulating the page.
861 * XXX get vm_page_spin_lock() here and move FREE->HOLD if necessary
864 vm_page_hold(vm_page_t m)
866 vm_page_spin_lock(m);
867 atomic_add_int(&m->hold_count, 1);
868 if (m->queue - m->pc == PQ_FREE) {
869 _vm_page_queue_spin_lock(m);
870 _vm_page_rem_queue_spinlocked(m);
871 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0);
872 _vm_page_queue_spin_unlock(m);
874 vm_page_spin_unlock(m);
878 * The opposite of vm_page_hold(). A page can be freed while being held,
879 * which places it on the PQ_HOLD queue. If we are able to busy the page
880 * after the hold count drops to zero we will move the page to the
881 * appropriate PQ_FREE queue by calling vm_page_free_toq().
884 vm_page_unhold(vm_page_t m)
886 vm_page_spin_lock(m);
887 atomic_add_int(&m->hold_count, -1);
888 if (m->hold_count == 0 && m->queue - m->pc == PQ_HOLD) {
889 _vm_page_queue_spin_lock(m);
890 _vm_page_rem_queue_spinlocked(m);
891 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0);
892 _vm_page_queue_spin_unlock(m);
894 vm_page_spin_unlock(m);
898 * Inserts the given vm_page into the object and object list.
900 * The pagetables are not updated but will presumably fault the page
901 * in if necessary, or if a kernel page the caller will at some point
902 * enter the page into the kernel's pmap. We are not allowed to block
903 * here so we *can't* do this anyway.
905 * This routine may not block.
906 * This routine must be called with the vm_object held.
907 * This routine must be called with a critical section held.
909 * This routine returns TRUE if the page was inserted into the object
910 * successfully, and FALSE if the page already exists in the object.
913 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
915 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
916 if (m->object != NULL)
917 panic("vm_page_insert: already inserted");
919 object->generation++;
922 * Record the object/offset pair in this page and add the
923 * pv_list_count of the page to the object.
925 * The vm_page spin lock is required for interactions with the pmap.
927 vm_page_spin_lock(m);
930 if (vm_page_rb_tree_RB_INSERT(&object->rb_memq, m)) {
933 vm_page_spin_unlock(m);
936 object->resident_page_count++;
937 /* atomic_add_int(&object->agg_pv_list_count, m->md.pv_list_count); */
938 vm_page_spin_unlock(m);
941 * Since we are inserting a new and possibly dirty page,
942 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags.
944 if ((m->valid & m->dirty) || (m->flags & PG_WRITEABLE))
945 vm_object_set_writeable_dirty(object);
948 * Checks for a swap assignment and sets PG_SWAPPED if appropriate.
950 swap_pager_page_inserted(m);
955 * Removes the given vm_page_t from the (object,index) table
957 * The underlying pmap entry (if any) is NOT removed here.
958 * This routine may not block.
960 * The page must be BUSY and will remain BUSY on return.
961 * No other requirements.
963 * NOTE: FreeBSD side effect was to unbusy the page on return. We leave
967 vm_page_remove(vm_page_t m)
971 if (m->object == NULL) {
975 if ((m->flags & PG_BUSY) == 0)
976 panic("vm_page_remove: page not busy");
980 vm_object_hold(object);
983 * Remove the page from the object and update the object.
985 * The vm_page spin lock is required for interactions with the pmap.
987 vm_page_spin_lock(m);
988 vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m);
989 object->resident_page_count--;
990 /* atomic_add_int(&object->agg_pv_list_count, -m->md.pv_list_count); */
992 vm_page_spin_unlock(m);
994 object->generation++;
996 vm_object_drop(object);
1000 * Locate and return the page at (object, pindex), or NULL if the
1001 * page could not be found.
1003 * The caller must hold the vm_object token.
1006 vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
1011 * Search the hash table for this object/offset pair
1013 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
1014 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
1015 KKASSERT(m == NULL || (m->object == object && m->pindex == pindex));
1020 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait)(struct vm_object *object,
1022 int also_m_busy, const char *msg
1028 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
1029 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
1031 KKASSERT(m->object == object && m->pindex == pindex);
1034 if (flags & PG_BUSY) {
1035 tsleep_interlock(m, 0);
1036 if (atomic_cmpset_int(&m->flags, flags,
1037 flags | PG_WANTED | PG_REFERENCED)) {
1038 tsleep(m, PINTERLOCKED, msg, 0);
1039 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq,
1042 } else if (also_m_busy && (flags & PG_SBUSY)) {
1043 tsleep_interlock(m, 0);
1044 if (atomic_cmpset_int(&m->flags, flags,
1045 flags | PG_WANTED | PG_REFERENCED)) {
1046 tsleep(m, PINTERLOCKED, msg, 0);
1047 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq,
1050 } else if (atomic_cmpset_int(&m->flags, flags,
1052 #ifdef VM_PAGE_DEBUG
1053 m->busy_func = func;
1054 m->busy_line = lineno;
1063 * Attempt to lookup and busy a page.
1065 * Returns NULL if the page could not be found
1067 * Returns a vm_page and error == TRUE if the page exists but could not
1070 * Returns a vm_page and error == FALSE on success.
1073 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try)(struct vm_object *object,
1075 int also_m_busy, int *errorp
1081 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
1082 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
1085 KKASSERT(m->object == object && m->pindex == pindex);
1088 if (flags & PG_BUSY) {
1092 if (also_m_busy && (flags & PG_SBUSY)) {
1096 if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) {
1097 #ifdef VM_PAGE_DEBUG
1098 m->busy_func = func;
1099 m->busy_line = lineno;
1108 * Caller must hold the related vm_object
1111 vm_page_next(vm_page_t m)
1115 next = vm_page_rb_tree_RB_NEXT(m);
1116 if (next && next->pindex != m->pindex + 1)
1124 * Move the given vm_page from its current object to the specified
1125 * target object/offset. The page must be busy and will remain so
1128 * new_object must be held.
1129 * This routine might block. XXX ?
1131 * NOTE: Swap associated with the page must be invalidated by the move. We
1132 * have to do this for several reasons: (1) we aren't freeing the
1133 * page, (2) we are dirtying the page, (3) the VM system is probably
1134 * moving the page from object A to B, and will then later move
1135 * the backing store from A to B and we can't have a conflict.
1137 * NOTE: We *always* dirty the page. It is necessary both for the
1138 * fact that we moved it, and because we may be invalidating
1139 * swap. If the page is on the cache, we have to deactivate it
1140 * or vm_page_dirty() will panic. Dirty pages are not allowed
1144 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
1146 KKASSERT(m->flags & PG_BUSY);
1147 ASSERT_LWKT_TOKEN_HELD(vm_object_token(new_object));
1149 ASSERT_LWKT_TOKEN_HELD(vm_object_token(m->object));
1152 if (vm_page_insert(m, new_object, new_pindex) == FALSE) {
1153 panic("vm_page_rename: target exists (%p,%"PRIu64")",
1154 new_object, new_pindex);
1156 if (m->queue - m->pc == PQ_CACHE)
1157 vm_page_deactivate(m);
1162 * vm_page_unqueue() without any wakeup. This routine is used when a page
1163 * is being moved between queues or otherwise is to remain BUSYied by the
1166 * This routine may not block.
1169 vm_page_unqueue_nowakeup(vm_page_t m)
1171 vm_page_and_queue_spin_lock(m);
1172 (void)_vm_page_rem_queue_spinlocked(m);
1173 vm_page_spin_unlock(m);
1177 * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon
1180 * This routine may not block.
1183 vm_page_unqueue(vm_page_t m)
1187 vm_page_and_queue_spin_lock(m);
1188 queue = _vm_page_rem_queue_spinlocked(m);
1189 if (queue == PQ_FREE || queue == PQ_CACHE) {
1190 vm_page_spin_unlock(m);
1191 pagedaemon_wakeup();
1193 vm_page_spin_unlock(m);
1198 * vm_page_list_find()
1200 * Find a page on the specified queue with color optimization.
1202 * The page coloring optimization attempts to locate a page that does
1203 * not overload other nearby pages in the object in the cpu's L1 or L2
1204 * caches. We need this optimization because cpu caches tend to be
1205 * physical caches, while object spaces tend to be virtual.
1207 * On MP systems each PQ_FREE and PQ_CACHE color queue has its own spinlock
1208 * and the algorithm is adjusted to localize allocations on a per-core basis.
1209 * This is done by 'twisting' the colors.
1211 * The page is returned spinlocked and removed from its queue (it will
1212 * be on PQ_NONE), or NULL. The page is not PG_BUSY'd. The caller
1213 * is responsible for dealing with the busy-page case (usually by
1214 * deactivating the page and looping).
1216 * NOTE: This routine is carefully inlined. A non-inlined version
1217 * is available for outside callers but the only critical path is
1218 * from within this source file.
1220 * NOTE: This routine assumes that the vm_pages found in PQ_CACHE and PQ_FREE
1221 * represent stable storage, allowing us to order our locks vm_page
1222 * first, then queue.
1226 _vm_page_list_find(int basequeue, int index, boolean_t prefer_zero)
1232 m = TAILQ_LAST(&vm_page_queues[basequeue+index].pl, pglist);
1234 m = TAILQ_FIRST(&vm_page_queues[basequeue+index].pl);
1236 m = _vm_page_list_find2(basequeue, index);
1239 vm_page_and_queue_spin_lock(m);
1240 if (m->queue == basequeue + index) {
1241 _vm_page_rem_queue_spinlocked(m);
1242 /* vm_page_t spin held, no queue spin */
1245 vm_page_and_queue_spin_unlock(m);
1251 _vm_page_list_find2(int basequeue, int index)
1255 struct vpgqueues *pq;
1257 pq = &vm_page_queues[basequeue];
1260 * Note that for the first loop, index+i and index-i wind up at the
1261 * same place. Even though this is not totally optimal, we've already
1262 * blown it by missing the cache case so we do not care.
1264 for (i = PQ_L2_SIZE / 2; i > 0; --i) {
1266 m = TAILQ_FIRST(&pq[(index + i) & PQ_L2_MASK].pl);
1268 _vm_page_and_queue_spin_lock(m);
1270 basequeue + ((index + i) & PQ_L2_MASK)) {
1271 _vm_page_rem_queue_spinlocked(m);
1274 _vm_page_and_queue_spin_unlock(m);
1277 m = TAILQ_FIRST(&pq[(index - i) & PQ_L2_MASK].pl);
1279 _vm_page_and_queue_spin_lock(m);
1281 basequeue + ((index - i) & PQ_L2_MASK)) {
1282 _vm_page_rem_queue_spinlocked(m);
1285 _vm_page_and_queue_spin_unlock(m);
1295 * Returns a vm_page candidate for allocation. The page is not busied so
1296 * it can move around. The caller must busy the page (and typically
1297 * deactivate it if it cannot be busied!)
1299 * Returns a spinlocked vm_page that has been removed from its queue.
1302 vm_page_list_find(int basequeue, int index, boolean_t prefer_zero)
1304 return(_vm_page_list_find(basequeue, index, prefer_zero));
1308 * Find a page on the cache queue with color optimization, remove it
1309 * from the queue, and busy it. The returned page will not be spinlocked.
1311 * A candidate failure will be deactivated. Candidates can fail due to
1312 * being busied by someone else, in which case they will be deactivated.
1314 * This routine may not block.
1318 vm_page_select_cache(u_short pg_color)
1323 m = _vm_page_list_find(PQ_CACHE, pg_color & PQ_L2_MASK, FALSE);
1327 * (m) has been removed from its queue and spinlocked
1329 if (vm_page_busy_try(m, TRUE)) {
1330 _vm_page_deactivate_locked(m, 0);
1331 vm_page_spin_unlock(m);
1333 kprintf("Warning: busy page %p found in cache\n", m);
1337 * We successfully busied the page
1339 if ((m->flags & PG_UNMANAGED) == 0 &&
1340 m->hold_count == 0 &&
1341 m->wire_count == 0) {
1342 vm_page_spin_unlock(m);
1343 pagedaemon_wakeup();
1346 _vm_page_deactivate_locked(m, 0);
1347 if (_vm_page_wakeup(m)) {
1348 vm_page_spin_unlock(m);
1351 vm_page_spin_unlock(m);
1359 * Find a free or zero page, with specified preference. We attempt to
1360 * inline the nominal case and fall back to _vm_page_select_free()
1361 * otherwise. A busied page is removed from the queue and returned.
1363 * This routine may not block.
1365 static __inline vm_page_t
1366 vm_page_select_free(u_short pg_color, boolean_t prefer_zero)
1371 m = _vm_page_list_find(PQ_FREE, pg_color & PQ_L2_MASK,
1375 if (vm_page_busy_try(m, TRUE)) {
1377 * Various mechanisms such as a pmap_collect can
1378 * result in a busy page on the free queue. We
1379 * have to move the page out of the way so we can
1380 * retry the allocation. If the other thread is not
1381 * allocating the page then m->valid will remain 0 and
1382 * the pageout daemon will free the page later on.
1384 * Since we could not busy the page, however, we
1385 * cannot make assumptions as to whether the page
1386 * will be allocated by the other thread or not,
1387 * so all we can do is deactivate it to move it out
1388 * of the way. In particular, if the other thread
1389 * wires the page it may wind up on the inactive
1390 * queue and the pageout daemon will have to deal
1391 * with that case too.
1393 _vm_page_deactivate_locked(m, 0);
1394 vm_page_spin_unlock(m);
1396 kprintf("Warning: busy page %p found in cache\n", m);
1400 * Theoretically if we are able to busy the page
1401 * atomic with the queue removal (using the vm_page
1402 * lock) nobody else should be able to mess with the
1405 KKASSERT((m->flags & PG_UNMANAGED) == 0);
1406 KKASSERT(m->hold_count == 0);
1407 KKASSERT(m->wire_count == 0);
1408 vm_page_spin_unlock(m);
1409 pagedaemon_wakeup();
1411 /* return busied and removed page */
1419 * This implements a per-cpu cache of free, zero'd, ready-to-go pages.
1420 * The idea is to populate this cache prior to acquiring any locks so
1421 * we don't wind up potentially zeroing VM pages (under heavy loads) while
1422 * holding potentialy contending locks.
1424 * Note that we allocate the page uninserted into anything and use a pindex
1425 * of 0, the vm_page_alloc() will effectively add gd_cpuid so these
1426 * allocations should wind up being uncontended. However, we still want
1427 * to rove across PQ_L2_SIZE.
1430 vm_page_pcpu_cache(void)
1433 globaldata_t gd = mycpu;
1436 if (gd->gd_vmpg_count < GD_MINVMPG) {
1438 while (gd->gd_vmpg_count < GD_MAXVMPG) {
1439 m = vm_page_alloc(NULL, ticks & ~ncpus2_mask,
1440 VM_ALLOC_NULL_OK | VM_ALLOC_NORMAL |
1441 VM_ALLOC_NULL_OK | VM_ALLOC_ZERO);
1442 if (gd->gd_vmpg_count < GD_MAXVMPG) {
1443 if ((m->flags & PG_ZERO) == 0) {
1444 pmap_zero_page(VM_PAGE_TO_PHYS(m));
1445 vm_page_flag_set(m, PG_ZERO);
1447 gd->gd_vmpg_array[gd->gd_vmpg_count++] = m;
1460 * Allocate and return a memory cell associated with this VM object/offset
1461 * pair. If object is NULL an unassociated page will be allocated.
1463 * The returned page will be busied and removed from its queues. This
1464 * routine can block and may return NULL if a race occurs and the page
1465 * is found to already exist at the specified (object, pindex).
1467 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain
1468 * VM_ALLOC_QUICK like normal but cannot use cache
1469 * VM_ALLOC_SYSTEM greater free drain
1470 * VM_ALLOC_INTERRUPT allow free list to be completely drained
1471 * VM_ALLOC_ZERO advisory request for pre-zero'd page only
1472 * VM_ALLOC_FORCE_ZERO advisory request for pre-zero'd page only
1473 * VM_ALLOC_NULL_OK ok to return NULL on insertion collision
1474 * (see vm_page_grab())
1475 * VM_ALLOC_USE_GD ok to use per-gd cache
1477 * The object must be held if not NULL
1478 * This routine may not block
1480 * Additional special handling is required when called from an interrupt
1481 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache
1485 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req)
1488 globaldata_t gd = mycpu;
1496 * Special per-cpu free VM page cache. The pages are pre-busied
1497 * and pre-zerod for us.
1499 if (gd->gd_vmpg_count && (page_req & VM_ALLOC_USE_GD)) {
1501 if (gd->gd_vmpg_count) {
1502 m = gd->gd_vmpg_array[--gd->gd_vmpg_count];
1513 * Cpu twist - cpu localization algorithm
1516 pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask) +
1517 (object->pg_color & ~ncpus_fit_mask);
1519 pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask);
1523 * Normal page coloring algorithm
1526 pg_color = object->pg_color + pindex;
1532 (VM_ALLOC_NORMAL|VM_ALLOC_QUICK|
1533 VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
1536 * Certain system threads (pageout daemon, buf_daemon's) are
1537 * allowed to eat deeper into the free page list.
1539 if (curthread->td_flags & TDF_SYSTHREAD)
1540 page_req |= VM_ALLOC_SYSTEM;
1543 if (vmstats.v_free_count > vmstats.v_free_reserved ||
1544 ((page_req & VM_ALLOC_INTERRUPT) && vmstats.v_free_count > 0) ||
1545 ((page_req & VM_ALLOC_SYSTEM) && vmstats.v_cache_count == 0 &&
1546 vmstats.v_free_count > vmstats.v_interrupt_free_min)
1549 * The free queue has sufficient free pages to take one out.
1551 if (page_req & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO))
1552 m = vm_page_select_free(pg_color, TRUE);
1554 m = vm_page_select_free(pg_color, FALSE);
1555 } else if (page_req & VM_ALLOC_NORMAL) {
1557 * Allocatable from the cache (non-interrupt only). On
1558 * success, we must free the page and try again, thus
1559 * ensuring that vmstats.v_*_free_min counters are replenished.
1562 if (curthread->td_preempted) {
1563 kprintf("vm_page_alloc(): warning, attempt to allocate"
1564 " cache page from preempting interrupt\n");
1567 m = vm_page_select_cache(pg_color);
1570 m = vm_page_select_cache(pg_color);
1573 * On success move the page into the free queue and loop.
1575 * Only do this if we can safely acquire the vm_object lock,
1576 * because this is effectively a random page and the caller
1577 * might be holding the lock shared, we don't want to
1581 KASSERT(m->dirty == 0,
1582 ("Found dirty cache page %p", m));
1583 if ((obj = m->object) != NULL) {
1584 if (vm_object_hold_try(obj)) {
1585 vm_page_protect(m, VM_PROT_NONE);
1587 /* m->object NULL here */
1588 vm_object_drop(obj);
1590 vm_page_deactivate(m);
1594 vm_page_protect(m, VM_PROT_NONE);
1601 * On failure return NULL
1603 #if defined(DIAGNOSTIC)
1604 if (vmstats.v_cache_count > 0)
1605 kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats.v_cache_count);
1607 vm_pageout_deficit++;
1608 pagedaemon_wakeup();
1612 * No pages available, wakeup the pageout daemon and give up.
1614 vm_pageout_deficit++;
1615 pagedaemon_wakeup();
1620 * v_free_count can race so loop if we don't find the expected
1627 * Good page found. The page has already been busied for us and
1628 * removed from its queues.
1630 KASSERT(m->dirty == 0,
1631 ("vm_page_alloc: free/cache page %p was dirty", m));
1632 KKASSERT(m->queue == PQ_NONE);
1638 * Initialize the structure, inheriting some flags but clearing
1639 * all the rest. The page has already been busied for us.
1641 vm_page_flag_clear(m, ~(PG_ZERO | PG_BUSY | PG_SBUSY));
1642 KKASSERT(m->wire_count == 0);
1643 KKASSERT(m->busy == 0);
1648 * Caller must be holding the object lock (asserted by
1649 * vm_page_insert()).
1651 * NOTE: Inserting a page here does not insert it into any pmaps
1652 * (which could cause us to block allocating memory).
1654 * NOTE: If no object an unassociated page is allocated, m->pindex
1655 * can be used by the caller for any purpose.
1658 if (vm_page_insert(m, object, pindex) == FALSE) {
1659 kprintf("PAGE RACE (%p:%d,%"PRIu64")\n",
1660 object, object->type, pindex);
1663 if ((page_req & VM_ALLOC_NULL_OK) == 0)
1671 * Don't wakeup too often - wakeup the pageout daemon when
1672 * we would be nearly out of memory.
1674 pagedaemon_wakeup();
1677 * A PG_BUSY page is returned.
1683 * Attempt to allocate contiguous physical memory with the specified
1687 vm_page_alloc_contig(vm_paddr_t low, vm_paddr_t high,
1688 unsigned long alignment, unsigned long boundary,
1693 alignment >>= PAGE_SHIFT;
1696 boundary >>= PAGE_SHIFT;
1699 size = (size + PAGE_MASK) >> PAGE_SHIFT;
1701 spin_lock(&vm_contig_spin);
1702 blk = alist_alloc(&vm_contig_alist, 0, size);
1703 if (blk == ALIST_BLOCK_NONE) {
1704 spin_unlock(&vm_contig_spin);
1706 kprintf("vm_page_alloc_contig: %ldk nospace\n",
1707 (size + PAGE_MASK) * (PAGE_SIZE / 1024));
1711 if (high && ((vm_paddr_t)(blk + size) << PAGE_SHIFT) > high) {
1712 alist_free(&vm_contig_alist, blk, size);
1713 spin_unlock(&vm_contig_spin);
1715 kprintf("vm_page_alloc_contig: %ldk high "
1717 (size + PAGE_MASK) * (PAGE_SIZE / 1024),
1722 spin_unlock(&vm_contig_spin);
1724 kprintf("vm_page_alloc_contig: %016jx/%ldk\n",
1725 (intmax_t)(vm_paddr_t)blk << PAGE_SHIFT,
1726 (size + PAGE_MASK) * (PAGE_SIZE / 1024));
1728 return (PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT));
1732 * Free contiguously allocated pages. The pages will be wired but not busy.
1733 * When freeing to the alist we leave them wired and not busy.
1736 vm_page_free_contig(vm_page_t m, unsigned long size)
1738 vm_paddr_t pa = VM_PAGE_TO_PHYS(m);
1739 vm_pindex_t start = pa >> PAGE_SHIFT;
1740 vm_pindex_t pages = (size + PAGE_MASK) >> PAGE_SHIFT;
1743 kprintf("vm_page_free_contig: %016jx/%ldk\n",
1744 (intmax_t)pa, size / 1024);
1746 if (pa < vm_low_phys_reserved) {
1747 KKASSERT(pa + size <= vm_low_phys_reserved);
1748 spin_lock(&vm_contig_spin);
1749 alist_free(&vm_contig_alist, start, pages);
1750 spin_unlock(&vm_contig_spin);
1753 vm_page_busy_wait(m, FALSE, "cpgfr");
1754 vm_page_unwire(m, 0);
1765 * Wait for sufficient free memory for nominal heavy memory use kernel
1769 vm_wait_nominal(void)
1771 while (vm_page_count_min(0))
1776 * Test if vm_wait_nominal() would block.
1779 vm_test_nominal(void)
1781 if (vm_page_count_min(0))
1787 * Block until free pages are available for allocation, called in various
1788 * places before memory allocations.
1790 * The caller may loop if vm_page_count_min() == FALSE so we cannot be
1791 * more generous then that.
1797 * never wait forever
1801 lwkt_gettoken(&vm_token);
1803 if (curthread == pagethread) {
1805 * The pageout daemon itself needs pages, this is bad.
1807 if (vm_page_count_min(0)) {
1808 vm_pageout_pages_needed = 1;
1809 tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo);
1813 * Wakeup the pageout daemon if necessary and wait.
1815 if (vm_page_count_target()) {
1816 if (vm_pages_needed == 0) {
1817 vm_pages_needed = 1;
1818 wakeup(&vm_pages_needed);
1820 ++vm_pages_waiting; /* SMP race ok */
1821 tsleep(&vmstats.v_free_count, 0, "vmwait", timo);
1824 lwkt_reltoken(&vm_token);
1828 * Block until free pages are available for allocation
1830 * Called only from vm_fault so that processes page faulting can be
1837 * Wakeup the pageout daemon if necessary and wait.
1839 if (vm_page_count_target()) {
1840 lwkt_gettoken(&vm_token);
1841 if (vm_page_count_target()) {
1842 if (vm_pages_needed == 0) {
1843 vm_pages_needed = 1;
1844 wakeup(&vm_pages_needed);
1846 ++vm_pages_waiting; /* SMP race ok */
1847 tsleep(&vmstats.v_free_count, 0, "pfault", hz);
1849 lwkt_reltoken(&vm_token);
1854 * Put the specified page on the active list (if appropriate). Ensure
1855 * that act_count is at least ACT_INIT but do not otherwise mess with it.
1857 * The caller should be holding the page busied ? XXX
1858 * This routine may not block.
1861 vm_page_activate(vm_page_t m)
1865 vm_page_spin_lock(m);
1866 if (m->queue - m->pc != PQ_ACTIVE) {
1867 _vm_page_queue_spin_lock(m);
1868 oqueue = _vm_page_rem_queue_spinlocked(m);
1869 /* page is left spinlocked, queue is unlocked */
1871 if (oqueue == PQ_CACHE)
1872 mycpu->gd_cnt.v_reactivated++;
1873 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
1874 if (m->act_count < ACT_INIT)
1875 m->act_count = ACT_INIT;
1876 _vm_page_add_queue_spinlocked(m, PQ_ACTIVE + m->pc, 0);
1878 _vm_page_and_queue_spin_unlock(m);
1879 if (oqueue == PQ_CACHE || oqueue == PQ_FREE)
1880 pagedaemon_wakeup();
1882 if (m->act_count < ACT_INIT)
1883 m->act_count = ACT_INIT;
1884 vm_page_spin_unlock(m);
1889 * Helper routine for vm_page_free_toq() and vm_page_cache(). This
1890 * routine is called when a page has been added to the cache or free
1893 * This routine may not block.
1895 static __inline void
1896 vm_page_free_wakeup(void)
1899 * If the pageout daemon itself needs pages, then tell it that
1900 * there are some free.
1902 if (vm_pageout_pages_needed &&
1903 vmstats.v_cache_count + vmstats.v_free_count >=
1904 vmstats.v_pageout_free_min
1906 wakeup(&vm_pageout_pages_needed);
1907 vm_pageout_pages_needed = 0;
1911 * Wakeup processes that are waiting on memory.
1913 * NOTE: vm_paging_target() is the pageout daemon's target, while
1914 * vm_page_count_target() is somewhere inbetween. We want
1915 * to wake processes up prior to the pageout daemon reaching
1916 * its target to provide some hysteresis.
1918 if (vm_pages_waiting) {
1919 if (!vm_page_count_target()) {
1921 * Plenty of pages are free, wakeup everyone.
1923 vm_pages_waiting = 0;
1924 wakeup(&vmstats.v_free_count);
1925 ++mycpu->gd_cnt.v_ppwakeups;
1926 } else if (!vm_page_count_min(0)) {
1928 * Some pages are free, wakeup someone.
1930 int wcount = vm_pages_waiting;
1933 vm_pages_waiting = wcount;
1934 wakeup_one(&vmstats.v_free_count);
1935 ++mycpu->gd_cnt.v_ppwakeups;
1941 * Returns the given page to the PQ_FREE or PQ_HOLD list and disassociates
1942 * it from its VM object.
1944 * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on
1945 * return (the page will have been freed).
1948 vm_page_free_toq(vm_page_t m)
1950 mycpu->gd_cnt.v_tfree++;
1951 KKASSERT((m->flags & PG_MAPPED) == 0);
1952 KKASSERT(m->flags & PG_BUSY);
1954 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) {
1955 kprintf("vm_page_free: pindex(%lu), busy(%d), "
1956 "PG_BUSY(%d), hold(%d)\n",
1957 (u_long)m->pindex, m->busy,
1958 ((m->flags & PG_BUSY) ? 1 : 0), m->hold_count);
1959 if ((m->queue - m->pc) == PQ_FREE)
1960 panic("vm_page_free: freeing free page");
1962 panic("vm_page_free: freeing busy page");
1966 * Remove from object, spinlock the page and its queues and
1967 * remove from any queue. No queue spinlock will be held
1968 * after this section (because the page was removed from any
1972 vm_page_and_queue_spin_lock(m);
1973 _vm_page_rem_queue_spinlocked(m);
1976 * No further management of fictitious pages occurs beyond object
1977 * and queue removal.
1979 if ((m->flags & PG_FICTITIOUS) != 0) {
1980 vm_page_spin_unlock(m);
1988 if (m->wire_count != 0) {
1989 if (m->wire_count > 1) {
1991 "vm_page_free: invalid wire count (%d), pindex: 0x%lx",
1992 m->wire_count, (long)m->pindex);
1994 panic("vm_page_free: freeing wired page");
1998 * Clear the UNMANAGED flag when freeing an unmanaged page.
2000 if (m->flags & PG_UNMANAGED) {
2001 vm_page_flag_clear(m, PG_UNMANAGED);
2004 if (m->hold_count != 0) {
2005 vm_page_flag_clear(m, PG_ZERO);
2006 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0);
2008 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0);
2012 * This sequence allows us to clear PG_BUSY while still holding
2013 * its spin lock, which reduces contention vs allocators. We
2014 * must not leave the queue locked or _vm_page_wakeup() may
2017 _vm_page_queue_spin_unlock(m);
2018 if (_vm_page_wakeup(m)) {
2019 vm_page_spin_unlock(m);
2022 vm_page_spin_unlock(m);
2024 vm_page_free_wakeup();
2028 * vm_page_free_fromq_fast()
2030 * Remove a non-zero page from one of the free queues; the page is removed for
2031 * zeroing, so do not issue a wakeup.
2034 vm_page_free_fromq_fast(void)
2040 for (i = 0; i < PQ_L2_SIZE; ++i) {
2041 m = vm_page_list_find(PQ_FREE, qi, FALSE);
2042 /* page is returned spinlocked and removed from its queue */
2044 if (vm_page_busy_try(m, TRUE)) {
2046 * We were unable to busy the page, deactivate
2049 _vm_page_deactivate_locked(m, 0);
2050 vm_page_spin_unlock(m);
2051 } else if (m->flags & PG_ZERO) {
2053 * The page is PG_ZERO, requeue it and loop
2055 _vm_page_add_queue_spinlocked(m,
2058 vm_page_queue_spin_unlock(m);
2059 if (_vm_page_wakeup(m)) {
2060 vm_page_spin_unlock(m);
2063 vm_page_spin_unlock(m);
2067 * The page is not PG_ZERO'd so return it.
2069 vm_page_spin_unlock(m);
2070 KKASSERT((m->flags & PG_UNMANAGED) == 0);
2071 KKASSERT(m->hold_count == 0);
2072 KKASSERT(m->wire_count == 0);
2077 qi = (qi + PQ_PRIME2) & PQ_L2_MASK;
2083 * vm_page_unmanage()
2085 * Prevent PV management from being done on the page. The page is
2086 * removed from the paging queues as if it were wired, and as a
2087 * consequence of no longer being managed the pageout daemon will not
2088 * touch it (since there is no way to locate the pte mappings for the
2089 * page). madvise() calls that mess with the pmap will also no longer
2090 * operate on the page.
2092 * Beyond that the page is still reasonably 'normal'. Freeing the page
2093 * will clear the flag.
2095 * This routine is used by OBJT_PHYS objects - objects using unswappable
2096 * physical memory as backing store rather then swap-backed memory and
2097 * will eventually be extended to support 4MB unmanaged physical
2100 * Caller must be holding the page busy.
2103 vm_page_unmanage(vm_page_t m)
2105 KKASSERT(m->flags & PG_BUSY);
2106 if ((m->flags & PG_UNMANAGED) == 0) {
2107 if (m->wire_count == 0)
2110 vm_page_flag_set(m, PG_UNMANAGED);
2114 * Mark this page as wired down by yet another map, removing it from
2115 * paging queues as necessary.
2117 * Caller must be holding the page busy.
2120 vm_page_wire(vm_page_t m)
2123 * Only bump the wire statistics if the page is not already wired,
2124 * and only unqueue the page if it is on some queue (if it is unmanaged
2125 * it is already off the queues). Don't do anything with fictitious
2126 * pages because they are always wired.
2128 KKASSERT(m->flags & PG_BUSY);
2129 if ((m->flags & PG_FICTITIOUS) == 0) {
2130 if (atomic_fetchadd_int(&m->wire_count, 1) == 0) {
2131 if ((m->flags & PG_UNMANAGED) == 0)
2133 atomic_add_int(&vmstats.v_wire_count, 1);
2135 KASSERT(m->wire_count != 0,
2136 ("vm_page_wire: wire_count overflow m=%p", m));
2141 * Release one wiring of this page, potentially enabling it to be paged again.
2143 * Many pages placed on the inactive queue should actually go
2144 * into the cache, but it is difficult to figure out which. What
2145 * we do instead, if the inactive target is well met, is to put
2146 * clean pages at the head of the inactive queue instead of the tail.
2147 * This will cause them to be moved to the cache more quickly and
2148 * if not actively re-referenced, freed more quickly. If we just
2149 * stick these pages at the end of the inactive queue, heavy filesystem
2150 * meta-data accesses can cause an unnecessary paging load on memory bound
2151 * processes. This optimization causes one-time-use metadata to be
2152 * reused more quickly.
2154 * BUT, if we are in a low-memory situation we have no choice but to
2155 * put clean pages on the cache queue.
2157 * A number of routines use vm_page_unwire() to guarantee that the page
2158 * will go into either the inactive or active queues, and will NEVER
2159 * be placed in the cache - for example, just after dirtying a page.
2160 * dirty pages in the cache are not allowed.
2162 * The page queues must be locked.
2163 * This routine may not block.
2166 vm_page_unwire(vm_page_t m, int activate)
2168 KKASSERT(m->flags & PG_BUSY);
2169 if (m->flags & PG_FICTITIOUS) {
2171 } else if (m->wire_count <= 0) {
2172 panic("vm_page_unwire: invalid wire count: %d", m->wire_count);
2174 if (atomic_fetchadd_int(&m->wire_count, -1) == 1) {
2175 atomic_add_int(&vmstats.v_wire_count, -1);
2176 if (m->flags & PG_UNMANAGED) {
2178 } else if (activate) {
2179 vm_page_spin_lock(m);
2180 _vm_page_add_queue_spinlocked(m,
2181 PQ_ACTIVE + m->pc, 0);
2182 _vm_page_and_queue_spin_unlock(m);
2184 vm_page_spin_lock(m);
2185 vm_page_flag_clear(m, PG_WINATCFLS);
2186 _vm_page_add_queue_spinlocked(m,
2187 PQ_INACTIVE + m->pc, 0);
2188 ++vm_swapcache_inactive_heuristic;
2189 _vm_page_and_queue_spin_unlock(m);
2196 * Move the specified page to the inactive queue. If the page has
2197 * any associated swap, the swap is deallocated.
2199 * Normally athead is 0 resulting in LRU operation. athead is set
2200 * to 1 if we want this page to be 'as if it were placed in the cache',
2201 * except without unmapping it from the process address space.
2203 * vm_page's spinlock must be held on entry and will remain held on return.
2204 * This routine may not block.
2207 _vm_page_deactivate_locked(vm_page_t m, int athead)
2212 * Ignore if already inactive.
2214 if (m->queue - m->pc == PQ_INACTIVE)
2216 _vm_page_queue_spin_lock(m);
2217 oqueue = _vm_page_rem_queue_spinlocked(m);
2219 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
2220 if (oqueue == PQ_CACHE)
2221 mycpu->gd_cnt.v_reactivated++;
2222 vm_page_flag_clear(m, PG_WINATCFLS);
2223 _vm_page_add_queue_spinlocked(m, PQ_INACTIVE + m->pc, athead);
2225 ++vm_swapcache_inactive_heuristic;
2227 _vm_page_queue_spin_unlock(m);
2228 /* leaves vm_page spinlocked */
2232 * Attempt to deactivate a page.
2237 vm_page_deactivate(vm_page_t m)
2239 vm_page_spin_lock(m);
2240 _vm_page_deactivate_locked(m, 0);
2241 vm_page_spin_unlock(m);
2245 vm_page_deactivate_locked(vm_page_t m)
2247 _vm_page_deactivate_locked(m, 0);
2251 * Attempt to move a page to PQ_CACHE.
2253 * Returns 0 on failure, 1 on success
2255 * The page should NOT be busied by the caller. This function will validate
2256 * whether the page can be safely moved to the cache.
2259 vm_page_try_to_cache(vm_page_t m)
2261 vm_page_spin_lock(m);
2262 if (vm_page_busy_try(m, TRUE)) {
2263 vm_page_spin_unlock(m);
2266 if (m->dirty || m->hold_count || m->wire_count ||
2267 (m->flags & PG_UNMANAGED)) {
2268 if (_vm_page_wakeup(m)) {
2269 vm_page_spin_unlock(m);
2272 vm_page_spin_unlock(m);
2276 vm_page_spin_unlock(m);
2279 * Page busied by us and no longer spinlocked. Dirty pages cannot
2280 * be moved to the cache.
2282 vm_page_test_dirty(m);
2292 * Attempt to free the page. If we cannot free it, we do nothing.
2293 * 1 is returned on success, 0 on failure.
2298 vm_page_try_to_free(vm_page_t m)
2300 vm_page_spin_lock(m);
2301 if (vm_page_busy_try(m, TRUE)) {
2302 vm_page_spin_unlock(m);
2305 if (m->dirty || m->hold_count || m->wire_count ||
2306 (m->flags & PG_UNMANAGED)) {
2307 if (_vm_page_wakeup(m)) {
2308 vm_page_spin_unlock(m);
2311 vm_page_spin_unlock(m);
2315 vm_page_spin_unlock(m);
2318 * Page busied by us and no longer spinlocked. Dirty pages will
2319 * not be freed by this function. We have to re-test the
2320 * dirty bit after cleaning out the pmaps.
2322 vm_page_test_dirty(m);
2327 vm_page_protect(m, VM_PROT_NONE);
2339 * Put the specified page onto the page cache queue (if appropriate).
2341 * The page must be busy, and this routine will release the busy and
2342 * possibly even free the page.
2345 vm_page_cache(vm_page_t m)
2347 if ((m->flags & PG_UNMANAGED) || m->busy ||
2348 m->wire_count || m->hold_count) {
2349 kprintf("vm_page_cache: attempting to cache busy/held page\n");
2355 * Already in the cache (and thus not mapped)
2357 if ((m->queue - m->pc) == PQ_CACHE) {
2358 KKASSERT((m->flags & PG_MAPPED) == 0);
2364 * Caller is required to test m->dirty, but note that the act of
2365 * removing the page from its maps can cause it to become dirty
2366 * on an SMP system due to another cpu running in usermode.
2369 panic("vm_page_cache: caching a dirty page, pindex: %ld",
2374 * Remove all pmaps and indicate that the page is not
2375 * writeable or mapped. Our vm_page_protect() call may
2376 * have blocked (especially w/ VM_PROT_NONE), so recheck
2379 vm_page_protect(m, VM_PROT_NONE);
2380 if ((m->flags & (PG_UNMANAGED|PG_MAPPED)) || m->busy ||
2381 m->wire_count || m->hold_count) {
2383 } else if (m->dirty) {
2384 vm_page_deactivate(m);
2387 _vm_page_and_queue_spin_lock(m);
2388 _vm_page_rem_queue_spinlocked(m);
2389 _vm_page_add_queue_spinlocked(m, PQ_CACHE + m->pc, 0);
2390 _vm_page_queue_spin_unlock(m);
2391 if (_vm_page_wakeup(m)) {
2392 vm_page_spin_unlock(m);
2395 vm_page_spin_unlock(m);
2397 vm_page_free_wakeup();
2402 * vm_page_dontneed()
2404 * Cache, deactivate, or do nothing as appropriate. This routine
2405 * is typically used by madvise() MADV_DONTNEED.
2407 * Generally speaking we want to move the page into the cache so
2408 * it gets reused quickly. However, this can result in a silly syndrome
2409 * due to the page recycling too quickly. Small objects will not be
2410 * fully cached. On the otherhand, if we move the page to the inactive
2411 * queue we wind up with a problem whereby very large objects
2412 * unnecessarily blow away our inactive and cache queues.
2414 * The solution is to move the pages based on a fixed weighting. We
2415 * either leave them alone, deactivate them, or move them to the cache,
2416 * where moving them to the cache has the highest weighting.
2417 * By forcing some pages into other queues we eventually force the
2418 * system to balance the queues, potentially recovering other unrelated
2419 * space from active. The idea is to not force this to happen too
2422 * The page must be busied.
2425 vm_page_dontneed(vm_page_t m)
2427 static int dnweight;
2434 * occassionally leave the page alone
2436 if ((dnw & 0x01F0) == 0 ||
2437 m->queue - m->pc == PQ_INACTIVE ||
2438 m->queue - m->pc == PQ_CACHE
2440 if (m->act_count >= ACT_INIT)
2446 * If vm_page_dontneed() is inactivating a page, it must clear
2447 * the referenced flag; otherwise the pagedaemon will see references
2448 * on the page in the inactive queue and reactivate it. Until the
2449 * page can move to the cache queue, madvise's job is not done.
2451 vm_page_flag_clear(m, PG_REFERENCED);
2452 pmap_clear_reference(m);
2455 vm_page_test_dirty(m);
2457 if (m->dirty || (dnw & 0x0070) == 0) {
2459 * Deactivate the page 3 times out of 32.
2464 * Cache the page 28 times out of every 32. Note that
2465 * the page is deactivated instead of cached, but placed
2466 * at the head of the queue instead of the tail.
2470 vm_page_spin_lock(m);
2471 _vm_page_deactivate_locked(m, head);
2472 vm_page_spin_unlock(m);
2476 * These routines manipulate the 'soft busy' count for a page. A soft busy
2477 * is almost like PG_BUSY except that it allows certain compatible operations
2478 * to occur on the page while it is busy. For example, a page undergoing a
2479 * write can still be mapped read-only.
2481 * Because vm_pages can overlap buffers m->busy can be > 1. m->busy is only
2482 * adjusted while the vm_page is PG_BUSY so the flash will occur when the
2483 * busy bit is cleared.
2486 vm_page_io_start(vm_page_t m)
2488 KASSERT(m->flags & PG_BUSY, ("vm_page_io_start: page not busy!!!"));
2489 atomic_add_char(&m->busy, 1);
2490 vm_page_flag_set(m, PG_SBUSY);
2494 vm_page_io_finish(vm_page_t m)
2496 KASSERT(m->flags & PG_BUSY, ("vm_page_io_finish: page not busy!!!"));
2497 atomic_subtract_char(&m->busy, 1);
2499 vm_page_flag_clear(m, PG_SBUSY);
2503 * Grab a page, blocking if it is busy and allocating a page if necessary.
2504 * A busy page is returned or NULL. The page may or may not be valid and
2505 * might not be on a queue (the caller is responsible for the disposition of
2508 * If VM_ALLOC_ZERO is specified and the grab must allocate a new page, the
2509 * page will be zero'd and marked valid.
2511 * If VM_ALLOC_FORCE_ZERO is specified the page will be zero'd and marked
2512 * valid even if it already exists.
2514 * If VM_ALLOC_RETRY is specified this routine will never return NULL. Also
2515 * note that VM_ALLOC_NORMAL must be specified if VM_ALLOC_RETRY is specified.
2516 * VM_ALLOC_NULL_OK is implied when VM_ALLOC_RETRY is specified.
2518 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is
2519 * always returned if we had blocked.
2521 * This routine may not be called from an interrupt.
2523 * PG_ZERO is *ALWAYS* cleared by this routine.
2525 * No other requirements.
2528 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
2533 KKASSERT(allocflags &
2534 (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
2535 vm_object_hold(object);
2537 m = vm_page_lookup_busy_try(object, pindex, TRUE, &error);
2539 vm_page_sleep_busy(m, TRUE, "pgrbwt");
2540 if ((allocflags & VM_ALLOC_RETRY) == 0) {
2545 } else if (m == NULL) {
2546 if (allocflags & VM_ALLOC_RETRY)
2547 allocflags |= VM_ALLOC_NULL_OK;
2548 m = vm_page_alloc(object, pindex,
2549 allocflags & ~VM_ALLOC_RETRY);
2553 if ((allocflags & VM_ALLOC_RETRY) == 0)
2562 * If VM_ALLOC_ZERO an invalid page will be zero'd and set valid.
2564 * If VM_ALLOC_FORCE_ZERO the page is unconditionally zero'd and set
2565 * valid even if already valid.
2567 if (m->valid == 0) {
2568 if (allocflags & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) {
2569 if ((m->flags & PG_ZERO) == 0)
2570 pmap_zero_page(VM_PAGE_TO_PHYS(m));
2571 m->valid = VM_PAGE_BITS_ALL;
2573 } else if (allocflags & VM_ALLOC_FORCE_ZERO) {
2574 pmap_zero_page(VM_PAGE_TO_PHYS(m));
2575 m->valid = VM_PAGE_BITS_ALL;
2577 vm_page_flag_clear(m, PG_ZERO);
2579 vm_object_drop(object);
2584 * Mapping function for valid bits or for dirty bits in
2585 * a page. May not block.
2587 * Inputs are required to range within a page.
2593 vm_page_bits(int base, int size)
2599 base + size <= PAGE_SIZE,
2600 ("vm_page_bits: illegal base/size %d/%d", base, size)
2603 if (size == 0) /* handle degenerate case */
2606 first_bit = base >> DEV_BSHIFT;
2607 last_bit = (base + size - 1) >> DEV_BSHIFT;
2609 return ((2 << last_bit) - (1 << first_bit));
2613 * Sets portions of a page valid and clean. The arguments are expected
2614 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
2615 * of any partial chunks touched by the range. The invalid portion of
2616 * such chunks will be zero'd.
2618 * NOTE: When truncating a buffer vnode_pager_setsize() will automatically
2619 * align base to DEV_BSIZE so as not to mark clean a partially
2620 * truncated device block. Otherwise the dirty page status might be
2623 * This routine may not block.
2625 * (base + size) must be less then or equal to PAGE_SIZE.
2628 _vm_page_zero_valid(vm_page_t m, int base, int size)
2633 if (size == 0) /* handle degenerate case */
2637 * If the base is not DEV_BSIZE aligned and the valid
2638 * bit is clear, we have to zero out a portion of the
2642 if ((frag = base & ~(DEV_BSIZE - 1)) != base &&
2643 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0
2645 pmap_zero_page_area(
2653 * If the ending offset is not DEV_BSIZE aligned and the
2654 * valid bit is clear, we have to zero out a portion of
2658 endoff = base + size;
2660 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff &&
2661 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0
2663 pmap_zero_page_area(
2666 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))
2672 * Set valid, clear dirty bits. If validating the entire
2673 * page we can safely clear the pmap modify bit. We also
2674 * use this opportunity to clear the PG_NOSYNC flag. If a process
2675 * takes a write fault on a MAP_NOSYNC memory area the flag will
2678 * We set valid bits inclusive of any overlap, but we can only
2679 * clear dirty bits for DEV_BSIZE chunks that are fully within
2682 * Page must be busied?
2683 * No other requirements.
2686 vm_page_set_valid(vm_page_t m, int base, int size)
2688 _vm_page_zero_valid(m, base, size);
2689 m->valid |= vm_page_bits(base, size);
2694 * Set valid bits and clear dirty bits.
2696 * NOTE: This function does not clear the pmap modified bit.
2697 * Also note that e.g. NFS may use a byte-granular base
2700 * WARNING: Page must be busied? But vfs_clean_one_page() will call
2701 * this without necessarily busying the page (via bdwrite()).
2702 * So for now vm_token must also be held.
2704 * No other requirements.
2707 vm_page_set_validclean(vm_page_t m, int base, int size)
2711 _vm_page_zero_valid(m, base, size);
2712 pagebits = vm_page_bits(base, size);
2713 m->valid |= pagebits;
2714 m->dirty &= ~pagebits;
2715 if (base == 0 && size == PAGE_SIZE) {
2716 /*pmap_clear_modify(m);*/
2717 vm_page_flag_clear(m, PG_NOSYNC);
2722 * Set valid & dirty. Used by buwrite()
2724 * WARNING: Page must be busied? But vfs_dirty_one_page() will
2725 * call this function in buwrite() so for now vm_token must
2728 * No other requirements.
2731 vm_page_set_validdirty(vm_page_t m, int base, int size)
2735 pagebits = vm_page_bits(base, size);
2736 m->valid |= pagebits;
2737 m->dirty |= pagebits;
2739 vm_object_set_writeable_dirty(m->object);
2745 * NOTE: This function does not clear the pmap modified bit.
2746 * Also note that e.g. NFS may use a byte-granular base
2749 * Page must be busied?
2750 * No other requirements.
2753 vm_page_clear_dirty(vm_page_t m, int base, int size)
2755 m->dirty &= ~vm_page_bits(base, size);
2756 if (base == 0 && size == PAGE_SIZE) {
2757 /*pmap_clear_modify(m);*/
2758 vm_page_flag_clear(m, PG_NOSYNC);
2763 * Make the page all-dirty.
2765 * Also make sure the related object and vnode reflect the fact that the
2766 * object may now contain a dirty page.
2768 * Page must be busied?
2769 * No other requirements.
2772 vm_page_dirty(vm_page_t m)
2775 int pqtype = m->queue - m->pc;
2777 KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE,
2778 ("vm_page_dirty: page in free/cache queue!"));
2779 if (m->dirty != VM_PAGE_BITS_ALL) {
2780 m->dirty = VM_PAGE_BITS_ALL;
2782 vm_object_set_writeable_dirty(m->object);
2787 * Invalidates DEV_BSIZE'd chunks within a page. Both the
2788 * valid and dirty bits for the effected areas are cleared.
2790 * Page must be busied?
2792 * No other requirements.
2795 vm_page_set_invalid(vm_page_t m, int base, int size)
2799 bits = vm_page_bits(base, size);
2802 m->object->generation++;
2806 * The kernel assumes that the invalid portions of a page contain
2807 * garbage, but such pages can be mapped into memory by user code.
2808 * When this occurs, we must zero out the non-valid portions of the
2809 * page so user code sees what it expects.
2811 * Pages are most often semi-valid when the end of a file is mapped
2812 * into memory and the file's size is not page aligned.
2814 * Page must be busied?
2815 * No other requirements.
2818 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
2824 * Scan the valid bits looking for invalid sections that
2825 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the
2826 * valid bit may be set ) have already been zerod by
2827 * vm_page_set_validclean().
2829 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
2830 if (i == (PAGE_SIZE / DEV_BSIZE) ||
2831 (m->valid & (1 << i))
2834 pmap_zero_page_area(
2837 (i - b) << DEV_BSHIFT
2845 * setvalid is TRUE when we can safely set the zero'd areas
2846 * as being valid. We can do this if there are no cache consistency
2847 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS.
2850 m->valid = VM_PAGE_BITS_ALL;
2854 * Is a (partial) page valid? Note that the case where size == 0
2855 * will return FALSE in the degenerate case where the page is entirely
2856 * invalid, and TRUE otherwise.
2859 * No other requirements.
2862 vm_page_is_valid(vm_page_t m, int base, int size)
2864 int bits = vm_page_bits(base, size);
2866 if (m->valid && ((m->valid & bits) == bits))
2873 * update dirty bits from pmap/mmu. May not block.
2875 * Caller must hold the page busy
2878 vm_page_test_dirty(vm_page_t m)
2880 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) {
2886 * Register an action, associating it with its vm_page
2889 vm_page_register_action(vm_page_action_t action, vm_page_event_t event)
2891 struct vm_page_action_list *list;
2894 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK;
2895 list = &action_list[hv];
2897 lwkt_gettoken(&vm_token);
2898 vm_page_flag_set(action->m, PG_ACTIONLIST);
2899 action->event = event;
2900 LIST_INSERT_HEAD(list, action, entry);
2901 lwkt_reltoken(&vm_token);
2905 * Unregister an action, disassociating it from its related vm_page
2908 vm_page_unregister_action(vm_page_action_t action)
2910 struct vm_page_action_list *list;
2913 lwkt_gettoken(&vm_token);
2914 if (action->event != VMEVENT_NONE) {
2915 action->event = VMEVENT_NONE;
2916 LIST_REMOVE(action, entry);
2918 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK;
2919 list = &action_list[hv];
2920 if (LIST_EMPTY(list))
2921 vm_page_flag_clear(action->m, PG_ACTIONLIST);
2923 lwkt_reltoken(&vm_token);
2927 * Issue an event on a VM page. Corresponding action structures are
2928 * removed from the page's list and called.
2930 * If the vm_page has no more pending action events we clear its
2931 * PG_ACTIONLIST flag.
2934 vm_page_event_internal(vm_page_t m, vm_page_event_t event)
2936 struct vm_page_action_list *list;
2937 struct vm_page_action *scan;
2938 struct vm_page_action *next;
2942 hv = (int)((intptr_t)m >> 8) & VMACTION_HMASK;
2943 list = &action_list[hv];
2946 lwkt_gettoken(&vm_token);
2947 LIST_FOREACH_MUTABLE(scan, list, entry, next) {
2949 if (scan->event == event) {
2950 scan->event = VMEVENT_NONE;
2951 LIST_REMOVE(scan, entry);
2952 scan->func(m, scan);
2960 vm_page_flag_clear(m, PG_ACTIONLIST);
2961 lwkt_reltoken(&vm_token);
2964 #include "opt_ddb.h"
2966 #include <sys/kernel.h>
2968 #include <ddb/ddb.h>
2970 DB_SHOW_COMMAND(page, vm_page_print_page_info)
2972 db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count);
2973 db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count);
2974 db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count);
2975 db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count);
2976 db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count);
2977 db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved);
2978 db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min);
2979 db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target);
2980 db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min);
2981 db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target);
2984 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
2987 db_printf("PQ_FREE:");
2988 for(i=0;i<PQ_L2_SIZE;i++) {
2989 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt);
2993 db_printf("PQ_CACHE:");
2994 for(i=0;i<PQ_L2_SIZE;i++) {
2995 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt);
2999 db_printf("PQ_ACTIVE:");
3000 for(i=0;i<PQ_L2_SIZE;i++) {
3001 db_printf(" %d", vm_page_queues[PQ_ACTIVE + i].lcnt);
3005 db_printf("PQ_INACTIVE:");
3006 for(i=0;i<PQ_L2_SIZE;i++) {
3007 db_printf(" %d", vm_page_queues[PQ_INACTIVE + i].lcnt);