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. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91
39 * $FreeBSD: src/sys/vm/vm_page.c,v 1.147.2.18 2002/03/10 05:03:19 alc Exp $
40 * $DragonFly: src/sys/vm/vm_page.c,v 1.40 2008/08/25 17:01:42 dillon Exp $
44 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
45 * All rights reserved.
47 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
49 * Permission to use, copy, modify and distribute this software and
50 * its documentation is hereby granted, provided that both the copyright
51 * notice and this permission notice appear in all copies of the
52 * software, derivative works or modified versions, and any portions
53 * thereof, and that both notices appear in supporting documentation.
55 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
56 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
57 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
59 * Carnegie Mellon requests users of this software to return to
61 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
62 * School of Computer Science
63 * Carnegie Mellon University
64 * Pittsburgh PA 15213-3890
66 * any improvements or extensions that they make and grant Carnegie the
67 * rights to redistribute these changes.
70 * Resident memory management module. The module manipulates 'VM pages'.
71 * A VM page is the core building block for memory management.
74 #include <sys/param.h>
75 #include <sys/systm.h>
76 #include <sys/malloc.h>
78 #include <sys/vmmeter.h>
79 #include <sys/vnode.h>
82 #include <vm/vm_param.h>
84 #include <vm/vm_kern.h>
86 #include <vm/vm_map.h>
87 #include <vm/vm_object.h>
88 #include <vm/vm_page.h>
89 #include <vm/vm_pageout.h>
90 #include <vm/vm_pager.h>
91 #include <vm/vm_extern.h>
92 #include <vm/swap_pager.h>
94 #include <machine/md_var.h>
96 #include <vm/vm_page2.h>
97 #include <sys/mplock2.h>
99 static void vm_page_queue_init(void);
100 static void vm_page_free_wakeup(void);
101 static vm_page_t vm_page_select_cache(vm_object_t, vm_pindex_t);
102 static vm_page_t _vm_page_list_find2(int basequeue, int index);
104 struct vpgqueues vm_page_queues[PQ_COUNT]; /* Array of tailq lists */
106 #define ASSERT_IN_CRIT_SECTION() KKASSERT(crit_test(curthread));
108 RB_GENERATE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare,
109 vm_pindex_t, pindex);
112 vm_page_queue_init(void)
116 for (i = 0; i < PQ_L2_SIZE; i++)
117 vm_page_queues[PQ_FREE+i].cnt = &vmstats.v_free_count;
118 for (i = 0; i < PQ_L2_SIZE; i++)
119 vm_page_queues[PQ_CACHE+i].cnt = &vmstats.v_cache_count;
121 vm_page_queues[PQ_INACTIVE].cnt = &vmstats.v_inactive_count;
122 vm_page_queues[PQ_ACTIVE].cnt = &vmstats.v_active_count;
123 vm_page_queues[PQ_HOLD].cnt = &vmstats.v_active_count;
124 /* PQ_NONE has no queue */
126 for (i = 0; i < PQ_COUNT; i++)
127 TAILQ_INIT(&vm_page_queues[i].pl);
131 * note: place in initialized data section? Is this necessary?
134 int vm_page_array_size = 0;
135 int vm_page_zero_count = 0;
136 vm_page_t vm_page_array = 0;
141 * Sets the page size, perhaps based upon the memory size.
142 * Must be called before any use of page-size dependent functions.
145 vm_set_page_size(void)
147 if (vmstats.v_page_size == 0)
148 vmstats.v_page_size = PAGE_SIZE;
149 if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0)
150 panic("vm_set_page_size: page size not a power of two");
156 * Add a new page to the freelist for use by the system. New pages
157 * are added to both the head and tail of the associated free page
158 * queue in a bottom-up fashion, so both zero'd and non-zero'd page
159 * requests pull 'recent' adds (higher physical addresses) first.
161 * Must be called in a critical section.
164 vm_add_new_page(vm_paddr_t pa)
166 struct vpgqueues *vpq;
169 ++vmstats.v_page_count;
170 ++vmstats.v_free_count;
171 m = PHYS_TO_VM_PAGE(pa);
174 m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK;
175 m->queue = m->pc + PQ_FREE;
176 KKASSERT(m->dirty == 0);
178 vpq = &vm_page_queues[m->queue];
180 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq);
182 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq);
183 vpq->flipflop = 1 - vpq->flipflop;
185 vm_page_queues[m->queue].lcnt++;
192 * Initializes the resident memory module.
194 * Allocates memory for the page cells, and for the object/offset-to-page
195 * hash table headers. Each page cell is initialized and placed on the
198 * starta/enda represents the range of physical memory addresses available
199 * for use (skipping memory already used by the kernel), subject to
200 * phys_avail[]. Note that phys_avail[] has already mapped out memory
201 * already in use by the kernel.
204 vm_page_startup(vm_offset_t vaddr)
208 vm_paddr_t page_range;
215 vm_paddr_t biggestone, biggestsize;
222 vaddr = round_page(vaddr);
224 for (i = 0; phys_avail[i + 1]; i += 2) {
225 phys_avail[i] = round_page64(phys_avail[i]);
226 phys_avail[i + 1] = trunc_page64(phys_avail[i + 1]);
229 for (i = 0; phys_avail[i + 1]; i += 2) {
230 vm_paddr_t size = phys_avail[i + 1] - phys_avail[i];
232 if (size > biggestsize) {
240 end = phys_avail[biggestone+1];
241 end = trunc_page(end);
244 * Initialize the queue headers for the free queue, the active queue
245 * and the inactive queue.
248 vm_page_queue_init();
250 /* VKERNELs don't support minidumps and as such don't need vm_page_dump */
251 #if !defined(_KERNEL_VIRTUAL)
253 * Allocate a bitmap to indicate that a random physical page
254 * needs to be included in a minidump.
256 * The amd64 port needs this to indicate which direct map pages
257 * need to be dumped, via calls to dump_add_page()/dump_drop_page().
259 * However, i386 still needs this workspace internally within the
260 * minidump code. In theory, they are not needed on i386, but are
261 * included should the sf_buf code decide to use them.
263 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE;
264 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY);
265 end -= vm_page_dump_size;
266 vm_page_dump = (void *)pmap_map(&vaddr, end, end + vm_page_dump_size,
267 VM_PROT_READ | VM_PROT_WRITE);
268 bzero((void *)vm_page_dump, vm_page_dump_size);
272 * Compute the number of pages of memory that will be available for
273 * use (taking into account the overhead of a page structure per
276 first_page = phys_avail[0] / PAGE_SIZE;
277 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page;
278 npages = (total - (page_range * sizeof(struct vm_page))) / PAGE_SIZE;
281 * Initialize the mem entry structures now, and put them in the free
284 new_end = trunc_page(end - page_range * sizeof(struct vm_page));
285 mapped = pmap_map(&vaddr, new_end, end,
286 VM_PROT_READ | VM_PROT_WRITE);
287 vm_page_array = (vm_page_t)mapped;
289 #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL)
291 * since pmap_map on amd64 returns stuff out of a direct-map region,
292 * we have to manually add these pages to the minidump tracking so
293 * that they can be dumped, including the vm_page_array.
295 for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE)
300 * Clear all of the page structures
302 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page));
303 vm_page_array_size = page_range;
306 * Construct the free queue(s) in ascending order (by physical
307 * address) so that the first 16MB of physical memory is allocated
308 * last rather than first. On large-memory machines, this avoids
309 * the exhaustion of low physical memory before isa_dmainit has run.
311 vmstats.v_page_count = 0;
312 vmstats.v_free_count = 0;
313 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) {
318 last_pa = phys_avail[i + 1];
319 while (pa < last_pa && npages-- > 0) {
328 * Scan comparison function for Red-Black tree scans. An inclusive
329 * (start,end) is expected. Other fields are not used.
332 rb_vm_page_scancmp(struct vm_page *p, void *data)
334 struct rb_vm_page_scan_info *info = data;
336 if (p->pindex < info->start_pindex)
338 if (p->pindex > info->end_pindex)
344 rb_vm_page_compare(struct vm_page *p1, struct vm_page *p2)
346 if (p1->pindex < p2->pindex)
348 if (p1->pindex > p2->pindex)
354 * Holding a page keeps it from being reused. Other parts of the system
355 * can still disassociate the page from its current object and free it, or
356 * perform read or write I/O on it and/or otherwise manipulate the page,
357 * but if the page is held the VM system will leave the page and its data
358 * intact and not reuse the page for other purposes until the last hold
359 * reference is released. (see vm_page_wire() if you want to prevent the
360 * page from being disassociated from its object too).
362 * The caller must hold vm_token.
364 * The caller must still validate the contents of the page and, if necessary,
365 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete
366 * before manipulating the page.
369 vm_page_hold(vm_page_t m)
371 ASSERT_LWKT_TOKEN_HELD(&vm_token);
376 * The opposite of vm_page_hold(). A page can be freed while being held,
377 * which places it on the PQ_HOLD queue. We must call vm_page_free_toq()
378 * in this case to actually free it once the hold count drops to 0.
380 * The caller must hold vm_token if non-blocking operation is desired,
381 * but otherwise does not need to.
384 vm_page_unhold(vm_page_t m)
386 lwkt_gettoken(&vm_token);
388 KASSERT(m->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!"));
389 if (m->hold_count == 0 && m->queue == PQ_HOLD) {
393 lwkt_reltoken(&vm_token);
397 * Inserts the given vm_page into the object and object list.
399 * The pagetables are not updated but will presumably fault the page
400 * in if necessary, or if a kernel page the caller will at some point
401 * enter the page into the kernel's pmap. We are not allowed to block
402 * here so we *can't* do this anyway.
404 * This routine may not block.
405 * This routine must be called with the vm_token held.
406 * This routine must be called with a critical section held.
409 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
411 ASSERT_IN_CRIT_SECTION();
412 ASSERT_LWKT_TOKEN_HELD(&vm_token);
413 if (m->object != NULL)
414 panic("vm_page_insert: already inserted");
417 * Record the object/offset pair in this page
423 * Insert it into the object.
425 ASSERT_MP_LOCK_HELD(curthread);
426 vm_page_rb_tree_RB_INSERT(&object->rb_memq, m);
427 object->generation++;
430 * show that the object has one more resident page.
432 object->resident_page_count++;
435 * Since we are inserting a new and possibly dirty page,
436 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags.
438 if ((m->valid & m->dirty) || (m->flags & PG_WRITEABLE))
439 vm_object_set_writeable_dirty(object);
442 * Checks for a swap assignment and sets PG_SWAPPED if appropriate.
444 swap_pager_page_inserted(m);
448 * Removes the given vm_page_t from the global (object,index) hash table
449 * and from the object's memq.
451 * The underlying pmap entry (if any) is NOT removed here.
452 * This routine may not block.
454 * The page must be BUSY and will remain BUSY on return.
455 * No other requirements.
457 * NOTE: FreeBSD side effect was to unbusy the page on return. We leave
461 vm_page_remove(vm_page_t m)
466 lwkt_gettoken(&vm_token);
467 if (m->object == NULL) {
468 lwkt_reltoken(&vm_token);
473 if ((m->flags & PG_BUSY) == 0)
474 panic("vm_page_remove: page not busy");
479 * Remove the page from the object and update the object.
481 ASSERT_MP_LOCK_HELD(curthread);
482 vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m);
483 object->resident_page_count--;
484 object->generation++;
487 lwkt_reltoken(&vm_token);
492 * Locate and return the page at (object, pindex), or NULL if the
493 * page could not be found.
495 * The caller must hold vm_token if non-blocking operation is desired.
498 vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
503 * Search the hash table for this object/offset pair
505 ASSERT_MP_LOCK_HELD(curthread);
507 lwkt_gettoken(&vm_token);
508 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
509 lwkt_reltoken(&vm_token);
511 KKASSERT(m == NULL || (m->object == object && m->pindex == pindex));
518 * Move the given memory entry from its current object to the specified
519 * target object/offset.
521 * The object must be locked.
522 * This routine may not block.
524 * Note: This routine will raise itself to splvm(), the caller need not.
526 * Note: Swap associated with the page must be invalidated by the move. We
527 * have to do this for several reasons: (1) we aren't freeing the
528 * page, (2) we are dirtying the page, (3) the VM system is probably
529 * moving the page from object A to B, and will then later move
530 * the backing store from A to B and we can't have a conflict.
532 * Note: We *always* dirty the page. It is necessary both for the
533 * fact that we moved it, and because we may be invalidating
534 * swap. If the page is on the cache, we have to deactivate it
535 * or vm_page_dirty() will panic. Dirty pages are not allowed
539 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
542 lwkt_gettoken(&vm_token);
544 vm_page_insert(m, new_object, new_pindex);
545 if (m->queue - m->pc == PQ_CACHE)
546 vm_page_deactivate(m);
549 lwkt_reltoken(&vm_token);
554 * vm_page_unqueue() without any wakeup. This routine is used when a page
555 * is being moved between queues or otherwise is to remain BUSYied by the
558 * The caller must hold vm_token
559 * This routine may not block.
562 vm_page_unqueue_nowakeup(vm_page_t m)
564 int queue = m->queue;
565 struct vpgqueues *pq;
567 ASSERT_LWKT_TOKEN_HELD(&vm_token);
568 if (queue != PQ_NONE) {
569 pq = &vm_page_queues[queue];
571 TAILQ_REMOVE(&pq->pl, m, pageq);
578 * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon
581 * The caller must hold vm_token
582 * This routine may not block.
585 vm_page_unqueue(vm_page_t m)
587 int queue = m->queue;
588 struct vpgqueues *pq;
590 ASSERT_LWKT_TOKEN_HELD(&vm_token);
591 if (queue != PQ_NONE) {
593 pq = &vm_page_queues[queue];
594 TAILQ_REMOVE(&pq->pl, m, pageq);
597 if ((queue - m->pc) == PQ_CACHE || (queue - m->pc) == PQ_FREE)
603 * vm_page_list_find()
605 * Find a page on the specified queue with color optimization.
607 * The page coloring optimization attempts to locate a page that does
608 * not overload other nearby pages in the object in the cpu's L1 or L2
609 * caches. We need this optimization because cpu caches tend to be
610 * physical caches, while object spaces tend to be virtual.
612 * Must be called with vm_token held.
613 * This routine may not block.
615 * Note that this routine is carefully inlined. A non-inlined version
616 * is available for outside callers but the only critical path is
617 * from within this source file.
621 _vm_page_list_find(int basequeue, int index, boolean_t prefer_zero)
626 m = TAILQ_LAST(&vm_page_queues[basequeue+index].pl, pglist);
628 m = TAILQ_FIRST(&vm_page_queues[basequeue+index].pl);
630 m = _vm_page_list_find2(basequeue, index);
635 _vm_page_list_find2(int basequeue, int index)
639 struct vpgqueues *pq;
641 pq = &vm_page_queues[basequeue];
644 * Note that for the first loop, index+i and index-i wind up at the
645 * same place. Even though this is not totally optimal, we've already
646 * blown it by missing the cache case so we do not care.
649 for(i = PQ_L2_SIZE / 2; i > 0; --i) {
650 if ((m = TAILQ_FIRST(&pq[(index + i) & PQ_L2_MASK].pl)) != NULL)
653 if ((m = TAILQ_FIRST(&pq[(index - i) & PQ_L2_MASK].pl)) != NULL)
660 * Must be called with vm_token held if the caller desired non-blocking
661 * operation and a stable result.
664 vm_page_list_find(int basequeue, int index, boolean_t prefer_zero)
666 return(_vm_page_list_find(basequeue, index, prefer_zero));
670 * Find a page on the cache queue with color optimization. As pages
671 * might be found, but not applicable, they are deactivated. This
672 * keeps us from using potentially busy cached pages.
674 * This routine may not block.
675 * Must be called with vm_token held.
678 vm_page_select_cache(vm_object_t object, vm_pindex_t pindex)
682 ASSERT_LWKT_TOKEN_HELD(&vm_token);
684 m = _vm_page_list_find(
686 (pindex + object->pg_color) & PQ_L2_MASK,
689 if (m && ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy ||
690 m->hold_count || m->wire_count)) {
691 vm_page_deactivate(m);
700 * Find a free or zero page, with specified preference. We attempt to
701 * inline the nominal case and fall back to _vm_page_select_free()
704 * This routine must be called with a critical section held.
705 * This routine may not block.
707 static __inline vm_page_t
708 vm_page_select_free(vm_object_t object, vm_pindex_t pindex, boolean_t prefer_zero)
712 m = _vm_page_list_find(
714 (pindex + object->pg_color) & PQ_L2_MASK,
723 * Allocate and return a memory cell associated with this VM object/offset
728 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain
729 * VM_ALLOC_QUICK like normal but cannot use cache
730 * VM_ALLOC_SYSTEM greater free drain
731 * VM_ALLOC_INTERRUPT allow free list to be completely drained
732 * VM_ALLOC_ZERO advisory request for pre-zero'd page
734 * The object must be locked.
735 * This routine may not block.
736 * The returned page will be marked PG_BUSY
738 * Additional special handling is required when called from an interrupt
739 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache
743 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req)
748 lwkt_gettoken(&vm_token);
750 KKASSERT(object != NULL);
751 KASSERT(!vm_page_lookup(object, pindex),
752 ("vm_page_alloc: page already allocated"));
754 (VM_ALLOC_NORMAL|VM_ALLOC_QUICK|
755 VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
758 * Certain system threads (pageout daemon, buf_daemon's) are
759 * allowed to eat deeper into the free page list.
761 if (curthread->td_flags & TDF_SYSTHREAD)
762 page_req |= VM_ALLOC_SYSTEM;
765 if (vmstats.v_free_count > vmstats.v_free_reserved ||
766 ((page_req & VM_ALLOC_INTERRUPT) && vmstats.v_free_count > 0) ||
767 ((page_req & VM_ALLOC_SYSTEM) && vmstats.v_cache_count == 0 &&
768 vmstats.v_free_count > vmstats.v_interrupt_free_min)
771 * The free queue has sufficient free pages to take one out.
773 if (page_req & VM_ALLOC_ZERO)
774 m = vm_page_select_free(object, pindex, TRUE);
776 m = vm_page_select_free(object, pindex, FALSE);
777 } else if (page_req & VM_ALLOC_NORMAL) {
779 * Allocatable from the cache (non-interrupt only). On
780 * success, we must free the page and try again, thus
781 * ensuring that vmstats.v_*_free_min counters are replenished.
784 if (curthread->td_preempted) {
785 kprintf("vm_page_alloc(): warning, attempt to allocate"
786 " cache page from preempting interrupt\n");
789 m = vm_page_select_cache(object, pindex);
792 m = vm_page_select_cache(object, pindex);
795 * On success move the page into the free queue and loop.
798 KASSERT(m->dirty == 0,
799 ("Found dirty cache page %p", m));
801 vm_page_protect(m, VM_PROT_NONE);
807 * On failure return NULL
809 lwkt_reltoken(&vm_token);
811 #if defined(DIAGNOSTIC)
812 if (vmstats.v_cache_count > 0)
813 kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats.v_cache_count);
815 vm_pageout_deficit++;
820 * No pages available, wakeup the pageout daemon and give up.
822 lwkt_reltoken(&vm_token);
824 vm_pageout_deficit++;
830 * Good page found. The page has not yet been busied. We are in
831 * a critical section.
833 KASSERT(m != NULL, ("vm_page_alloc(): missing page on free queue\n"));
834 KASSERT(m->dirty == 0,
835 ("vm_page_alloc: free/cache page %p was dirty", m));
838 * Remove from free queue
840 vm_page_unqueue_nowakeup(m);
843 * Initialize structure. Only the PG_ZERO flag is inherited. Set
846 if (m->flags & PG_ZERO) {
847 vm_page_zero_count--;
848 m->flags = PG_ZERO | PG_BUSY;
859 * vm_page_insert() is safe prior to the crit_exit(). Note also that
860 * inserting a page here does not insert it into the pmap (which
861 * could cause us to block allocating memory). We cannot block
864 vm_page_insert(m, object, pindex);
867 * Don't wakeup too often - wakeup the pageout daemon when
868 * we would be nearly out of memory.
872 lwkt_reltoken(&vm_token);
876 * A PG_BUSY page is returned.
882 * Wait for sufficient free memory for nominal heavy memory use kernel
886 vm_wait_nominal(void)
888 while (vm_page_count_min(0))
893 * Test if vm_wait_nominal() would block.
896 vm_test_nominal(void)
898 if (vm_page_count_min(0))
904 * Block until free pages are available for allocation, called in various
905 * places before memory allocations.
911 lwkt_gettoken(&vm_token);
912 if (curthread == pagethread) {
913 vm_pageout_pages_needed = 1;
914 tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo);
916 if (vm_pages_needed == 0) {
918 wakeup(&vm_pages_needed);
920 tsleep(&vmstats.v_free_count, 0, "vmwait", timo);
922 lwkt_reltoken(&vm_token);
927 * Block until free pages are available for allocation
929 * Called only in vm_fault so that processes page faulting can be
936 lwkt_gettoken(&vm_token);
937 if (vm_pages_needed == 0) {
939 wakeup(&vm_pages_needed);
941 tsleep(&vmstats.v_free_count, 0, "pfault", 0);
942 lwkt_reltoken(&vm_token);
947 * Put the specified page on the active list (if appropriate). Ensure
948 * that act_count is at least ACT_INIT but do not otherwise mess with it.
950 * The page queues must be locked.
951 * This routine may not block.
954 vm_page_activate(vm_page_t m)
957 lwkt_gettoken(&vm_token);
958 if (m->queue != PQ_ACTIVE) {
959 if ((m->queue - m->pc) == PQ_CACHE)
960 mycpu->gd_cnt.v_reactivated++;
964 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
965 m->queue = PQ_ACTIVE;
966 vm_page_queues[PQ_ACTIVE].lcnt++;
967 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl,
969 if (m->act_count < ACT_INIT)
970 m->act_count = ACT_INIT;
971 vmstats.v_active_count++;
974 if (m->act_count < ACT_INIT)
975 m->act_count = ACT_INIT;
977 lwkt_reltoken(&vm_token);
982 * Helper routine for vm_page_free_toq() and vm_page_cache(). This
983 * routine is called when a page has been added to the cache or free
986 * This routine may not block.
987 * This routine must be called at splvm()
990 vm_page_free_wakeup(void)
993 * if pageout daemon needs pages, then tell it that there are
996 if (vm_pageout_pages_needed &&
997 vmstats.v_cache_count + vmstats.v_free_count >=
998 vmstats.v_pageout_free_min
1000 wakeup(&vm_pageout_pages_needed);
1001 vm_pageout_pages_needed = 0;
1005 * wakeup processes that are waiting on memory if we hit a
1006 * high water mark. And wakeup scheduler process if we have
1007 * lots of memory. this process will swapin processes.
1009 if (vm_pages_needed && !vm_page_count_min(0)) {
1010 vm_pages_needed = 0;
1011 wakeup(&vmstats.v_free_count);
1018 * Returns the given page to the PQ_FREE list, disassociating it with
1021 * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on
1022 * return (the page will have been freed). No particular spl is required
1025 * This routine may not block.
1028 vm_page_free_toq(vm_page_t m)
1030 struct vpgqueues *pq;
1033 lwkt_gettoken(&vm_token);
1034 mycpu->gd_cnt.v_tfree++;
1036 KKASSERT((m->flags & PG_MAPPED) == 0);
1038 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) {
1040 "vm_page_free: pindex(%lu), busy(%d), PG_BUSY(%d), hold(%d)\n",
1041 (u_long)m->pindex, m->busy, (m->flags & PG_BUSY) ? 1 : 0,
1043 if ((m->queue - m->pc) == PQ_FREE)
1044 panic("vm_page_free: freeing free page");
1046 panic("vm_page_free: freeing busy page");
1050 * unqueue, then remove page. Note that we cannot destroy
1051 * the page here because we do not want to call the pager's
1052 * callback routine until after we've put the page on the
1053 * appropriate free queue.
1055 vm_page_unqueue_nowakeup(m);
1059 * No further management of fictitious pages occurs beyond object
1060 * and queue removal.
1062 if ((m->flags & PG_FICTITIOUS) != 0) {
1064 lwkt_reltoken(&vm_token);
1072 if (m->wire_count != 0) {
1073 if (m->wire_count > 1) {
1075 "vm_page_free: invalid wire count (%d), pindex: 0x%lx",
1076 m->wire_count, (long)m->pindex);
1078 panic("vm_page_free: freeing wired page");
1082 * Clear the UNMANAGED flag when freeing an unmanaged page.
1084 if (m->flags & PG_UNMANAGED) {
1085 m->flags &= ~PG_UNMANAGED;
1088 if (m->hold_count != 0) {
1089 m->flags &= ~PG_ZERO;
1092 m->queue = PQ_FREE + m->pc;
1094 pq = &vm_page_queues[m->queue];
1099 * Put zero'd pages on the end ( where we look for zero'd pages
1100 * first ) and non-zerod pages at the head.
1102 if (m->flags & PG_ZERO) {
1103 TAILQ_INSERT_TAIL(&pq->pl, m, pageq);
1104 ++vm_page_zero_count;
1106 TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
1109 vm_page_free_wakeup();
1110 lwkt_reltoken(&vm_token);
1115 * vm_page_free_fromq_fast()
1117 * Remove a non-zero page from one of the free queues; the page is removed for
1118 * zeroing, so do not issue a wakeup.
1123 vm_page_free_fromq_fast(void)
1130 lwkt_gettoken(&vm_token);
1131 for (i = 0; i < PQ_L2_SIZE; ++i) {
1132 m = vm_page_list_find(PQ_FREE, qi, FALSE);
1133 qi = (qi + PQ_PRIME2) & PQ_L2_MASK;
1134 if (m && (m->flags & PG_ZERO) == 0) {
1135 vm_page_unqueue_nowakeup(m);
1141 lwkt_reltoken(&vm_token);
1147 * vm_page_unmanage()
1149 * Prevent PV management from being done on the page. The page is
1150 * removed from the paging queues as if it were wired, and as a
1151 * consequence of no longer being managed the pageout daemon will not
1152 * touch it (since there is no way to locate the pte mappings for the
1153 * page). madvise() calls that mess with the pmap will also no longer
1154 * operate on the page.
1156 * Beyond that the page is still reasonably 'normal'. Freeing the page
1157 * will clear the flag.
1159 * This routine is used by OBJT_PHYS objects - objects using unswappable
1160 * physical memory as backing store rather then swap-backed memory and
1161 * will eventually be extended to support 4MB unmanaged physical
1164 * Must be called with a critical section held.
1165 * Must be called with vm_token held.
1168 vm_page_unmanage(vm_page_t m)
1170 ASSERT_IN_CRIT_SECTION();
1171 ASSERT_LWKT_TOKEN_HELD(&vm_token);
1172 if ((m->flags & PG_UNMANAGED) == 0) {
1173 if (m->wire_count == 0)
1176 vm_page_flag_set(m, PG_UNMANAGED);
1180 * Mark this page as wired down by yet another map, removing it from
1181 * paging queues as necessary.
1183 * The page queues must be locked.
1184 * This routine may not block.
1187 vm_page_wire(vm_page_t m)
1190 * Only bump the wire statistics if the page is not already wired,
1191 * and only unqueue the page if it is on some queue (if it is unmanaged
1192 * it is already off the queues). Don't do anything with fictitious
1193 * pages because they are always wired.
1196 lwkt_gettoken(&vm_token);
1197 if ((m->flags & PG_FICTITIOUS) == 0) {
1198 if (m->wire_count == 0) {
1199 if ((m->flags & PG_UNMANAGED) == 0)
1201 vmstats.v_wire_count++;
1204 KASSERT(m->wire_count != 0,
1205 ("vm_page_wire: wire_count overflow m=%p", m));
1207 lwkt_reltoken(&vm_token);
1212 * Release one wiring of this page, potentially enabling it to be paged again.
1214 * Many pages placed on the inactive queue should actually go
1215 * into the cache, but it is difficult to figure out which. What
1216 * we do instead, if the inactive target is well met, is to put
1217 * clean pages at the head of the inactive queue instead of the tail.
1218 * This will cause them to be moved to the cache more quickly and
1219 * if not actively re-referenced, freed more quickly. If we just
1220 * stick these pages at the end of the inactive queue, heavy filesystem
1221 * meta-data accesses can cause an unnecessary paging load on memory bound
1222 * processes. This optimization causes one-time-use metadata to be
1223 * reused more quickly.
1225 * BUT, if we are in a low-memory situation we have no choice but to
1226 * put clean pages on the cache queue.
1228 * A number of routines use vm_page_unwire() to guarantee that the page
1229 * will go into either the inactive or active queues, and will NEVER
1230 * be placed in the cache - for example, just after dirtying a page.
1231 * dirty pages in the cache are not allowed.
1233 * The page queues must be locked.
1234 * This routine may not block.
1237 vm_page_unwire(vm_page_t m, int activate)
1240 lwkt_gettoken(&vm_token);
1241 if (m->flags & PG_FICTITIOUS) {
1243 } else if (m->wire_count <= 0) {
1244 panic("vm_page_unwire: invalid wire count: %d", m->wire_count);
1246 if (--m->wire_count == 0) {
1247 --vmstats.v_wire_count;
1248 if (m->flags & PG_UNMANAGED) {
1250 } else if (activate) {
1252 &vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1253 m->queue = PQ_ACTIVE;
1254 vm_page_queues[PQ_ACTIVE].lcnt++;
1255 vmstats.v_active_count++;
1257 vm_page_flag_clear(m, PG_WINATCFLS);
1259 &vm_page_queues[PQ_INACTIVE].pl, m, pageq);
1260 m->queue = PQ_INACTIVE;
1261 vm_page_queues[PQ_INACTIVE].lcnt++;
1262 vmstats.v_inactive_count++;
1263 ++vm_swapcache_inactive_heuristic;
1267 lwkt_reltoken(&vm_token);
1273 * Move the specified page to the inactive queue. If the page has
1274 * any associated swap, the swap is deallocated.
1276 * Normally athead is 0 resulting in LRU operation. athead is set
1277 * to 1 if we want this page to be 'as if it were placed in the cache',
1278 * except without unmapping it from the process address space.
1280 * This routine may not block.
1281 * The caller must hold vm_token.
1283 static __inline void
1284 _vm_page_deactivate(vm_page_t m, int athead)
1287 * Ignore if already inactive.
1289 if (m->queue == PQ_INACTIVE)
1292 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
1293 if ((m->queue - m->pc) == PQ_CACHE)
1294 mycpu->gd_cnt.v_reactivated++;
1295 vm_page_flag_clear(m, PG_WINATCFLS);
1298 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl,
1301 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl,
1303 ++vm_swapcache_inactive_heuristic;
1305 m->queue = PQ_INACTIVE;
1306 vm_page_queues[PQ_INACTIVE].lcnt++;
1307 vmstats.v_inactive_count++;
1312 * Attempt to deactivate a page.
1317 vm_page_deactivate(vm_page_t m)
1320 lwkt_gettoken(&vm_token);
1321 _vm_page_deactivate(m, 0);
1322 lwkt_reltoken(&vm_token);
1327 * Attempt to move a page to PQ_CACHE.
1328 * Returns 0 on failure, 1 on success
1333 vm_page_try_to_cache(vm_page_t m)
1336 lwkt_gettoken(&vm_token);
1337 if (m->dirty || m->hold_count || m->busy || m->wire_count ||
1338 (m->flags & (PG_BUSY|PG_UNMANAGED))) {
1339 lwkt_reltoken(&vm_token);
1343 vm_page_test_dirty(m);
1345 lwkt_reltoken(&vm_token);
1350 lwkt_reltoken(&vm_token);
1356 * Attempt to free the page. If we cannot free it, we do nothing.
1357 * 1 is returned on success, 0 on failure.
1362 vm_page_try_to_free(vm_page_t m)
1365 lwkt_gettoken(&vm_token);
1366 if (m->dirty || m->hold_count || m->busy || m->wire_count ||
1367 (m->flags & (PG_BUSY|PG_UNMANAGED))) {
1368 lwkt_reltoken(&vm_token);
1372 vm_page_test_dirty(m);
1374 lwkt_reltoken(&vm_token);
1379 vm_page_protect(m, VM_PROT_NONE);
1381 lwkt_reltoken(&vm_token);
1389 * Put the specified page onto the page cache queue (if appropriate).
1391 * The caller must hold vm_token.
1392 * This routine may not block.
1395 vm_page_cache(vm_page_t m)
1397 ASSERT_IN_CRIT_SECTION();
1398 ASSERT_LWKT_TOKEN_HELD(&vm_token);
1400 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy ||
1401 m->wire_count || m->hold_count) {
1402 kprintf("vm_page_cache: attempting to cache busy/held page\n");
1407 * Already in the cache (and thus not mapped)
1409 if ((m->queue - m->pc) == PQ_CACHE) {
1410 KKASSERT((m->flags & PG_MAPPED) == 0);
1415 * Caller is required to test m->dirty, but note that the act of
1416 * removing the page from its maps can cause it to become dirty
1417 * on an SMP system due to another cpu running in usermode.
1420 panic("vm_page_cache: caching a dirty page, pindex: %ld",
1425 * Remove all pmaps and indicate that the page is not
1426 * writeable or mapped. Our vm_page_protect() call may
1427 * have blocked (especially w/ VM_PROT_NONE), so recheck
1431 vm_page_protect(m, VM_PROT_NONE);
1433 if ((m->flags & (PG_BUSY|PG_UNMANAGED|PG_MAPPED)) || m->busy ||
1434 m->wire_count || m->hold_count) {
1436 } else if (m->dirty) {
1437 vm_page_deactivate(m);
1439 vm_page_unqueue_nowakeup(m);
1440 m->queue = PQ_CACHE + m->pc;
1441 vm_page_queues[m->queue].lcnt++;
1442 TAILQ_INSERT_TAIL(&vm_page_queues[m->queue].pl, m, pageq);
1443 vmstats.v_cache_count++;
1444 vm_page_free_wakeup();
1449 * vm_page_dontneed()
1451 * Cache, deactivate, or do nothing as appropriate. This routine
1452 * is typically used by madvise() MADV_DONTNEED.
1454 * Generally speaking we want to move the page into the cache so
1455 * it gets reused quickly. However, this can result in a silly syndrome
1456 * due to the page recycling too quickly. Small objects will not be
1457 * fully cached. On the otherhand, if we move the page to the inactive
1458 * queue we wind up with a problem whereby very large objects
1459 * unnecessarily blow away our inactive and cache queues.
1461 * The solution is to move the pages based on a fixed weighting. We
1462 * either leave them alone, deactivate them, or move them to the cache,
1463 * where moving them to the cache has the highest weighting.
1464 * By forcing some pages into other queues we eventually force the
1465 * system to balance the queues, potentially recovering other unrelated
1466 * space from active. The idea is to not force this to happen too
1472 vm_page_dontneed(vm_page_t m)
1474 static int dnweight;
1481 * occassionally leave the page alone
1484 lwkt_gettoken(&vm_token);
1485 if ((dnw & 0x01F0) == 0 ||
1486 m->queue == PQ_INACTIVE ||
1487 m->queue - m->pc == PQ_CACHE
1489 if (m->act_count >= ACT_INIT)
1491 lwkt_reltoken(&vm_token);
1497 vm_page_test_dirty(m);
1499 if (m->dirty || (dnw & 0x0070) == 0) {
1501 * Deactivate the page 3 times out of 32.
1506 * Cache the page 28 times out of every 32. Note that
1507 * the page is deactivated instead of cached, but placed
1508 * at the head of the queue instead of the tail.
1512 _vm_page_deactivate(m, head);
1513 lwkt_reltoken(&vm_token);
1518 * Grab a page, blocking if it is busy and allocating a page if necessary.
1519 * A busy page is returned or NULL.
1521 * If VM_ALLOC_RETRY is specified VM_ALLOC_NORMAL must also be specified.
1522 * If VM_ALLOC_RETRY is not specified
1524 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is
1525 * always returned if we had blocked.
1526 * This routine will never return NULL if VM_ALLOC_RETRY is set.
1527 * This routine may not be called from an interrupt.
1528 * The returned page may not be entirely valid.
1530 * This routine may be called from mainline code without spl protection and
1531 * be guarenteed a busied page associated with the object at the specified
1537 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
1542 KKASSERT(allocflags &
1543 (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
1545 lwkt_gettoken(&vm_token);
1547 if ((m = vm_page_lookup(object, pindex)) != NULL) {
1548 if (m->busy || (m->flags & PG_BUSY)) {
1549 generation = object->generation;
1551 while ((object->generation == generation) &&
1552 (m->busy || (m->flags & PG_BUSY))) {
1553 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED);
1554 tsleep(m, 0, "pgrbwt", 0);
1555 if ((allocflags & VM_ALLOC_RETRY) == 0) {
1566 m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY);
1569 if ((allocflags & VM_ALLOC_RETRY) == 0)
1574 lwkt_reltoken(&vm_token);
1580 * Mapping function for valid bits or for dirty bits in
1581 * a page. May not block.
1583 * Inputs are required to range within a page.
1589 vm_page_bits(int base, int size)
1595 base + size <= PAGE_SIZE,
1596 ("vm_page_bits: illegal base/size %d/%d", base, size)
1599 if (size == 0) /* handle degenerate case */
1602 first_bit = base >> DEV_BSHIFT;
1603 last_bit = (base + size - 1) >> DEV_BSHIFT;
1605 return ((2 << last_bit) - (1 << first_bit));
1609 * Sets portions of a page valid and clean. The arguments are expected
1610 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
1611 * of any partial chunks touched by the range. The invalid portion of
1612 * such chunks will be zero'd.
1614 * NOTE: When truncating a buffer vnode_pager_setsize() will automatically
1615 * align base to DEV_BSIZE so as not to mark clean a partially
1616 * truncated device block. Otherwise the dirty page status might be
1619 * This routine may not block.
1621 * (base + size) must be less then or equal to PAGE_SIZE.
1624 _vm_page_zero_valid(vm_page_t m, int base, int size)
1629 if (size == 0) /* handle degenerate case */
1633 * If the base is not DEV_BSIZE aligned and the valid
1634 * bit is clear, we have to zero out a portion of the
1638 if ((frag = base & ~(DEV_BSIZE - 1)) != base &&
1639 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0
1641 pmap_zero_page_area(
1649 * If the ending offset is not DEV_BSIZE aligned and the
1650 * valid bit is clear, we have to zero out a portion of
1654 endoff = base + size;
1656 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff &&
1657 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0
1659 pmap_zero_page_area(
1662 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))
1668 * Set valid, clear dirty bits. If validating the entire
1669 * page we can safely clear the pmap modify bit. We also
1670 * use this opportunity to clear the PG_NOSYNC flag. If a process
1671 * takes a write fault on a MAP_NOSYNC memory area the flag will
1674 * We set valid bits inclusive of any overlap, but we can only
1675 * clear dirty bits for DEV_BSIZE chunks that are fully within
1678 * Page must be busied?
1679 * No other requirements.
1682 vm_page_set_valid(vm_page_t m, int base, int size)
1684 _vm_page_zero_valid(m, base, size);
1685 m->valid |= vm_page_bits(base, size);
1690 * Set valid bits and clear dirty bits.
1692 * NOTE: This function does not clear the pmap modified bit.
1693 * Also note that e.g. NFS may use a byte-granular base
1696 * Page must be busied?
1697 * No other requirements.
1700 vm_page_set_validclean(vm_page_t m, int base, int size)
1704 _vm_page_zero_valid(m, base, size);
1705 pagebits = vm_page_bits(base, size);
1706 m->valid |= pagebits;
1707 m->dirty &= ~pagebits;
1708 if (base == 0 && size == PAGE_SIZE) {
1709 /*pmap_clear_modify(m);*/
1710 vm_page_flag_clear(m, PG_NOSYNC);
1715 * Set valid & dirty. Used by buwrite()
1717 * Page must be busied?
1718 * No other requirements.
1721 vm_page_set_validdirty(vm_page_t m, int base, int size)
1725 pagebits = vm_page_bits(base, size);
1726 m->valid |= pagebits;
1727 m->dirty |= pagebits;
1729 vm_object_set_writeable_dirty(m->object);
1735 * NOTE: This function does not clear the pmap modified bit.
1736 * Also note that e.g. NFS may use a byte-granular base
1739 * Page must be busied?
1740 * No other requirements.
1743 vm_page_clear_dirty(vm_page_t m, int base, int size)
1745 m->dirty &= ~vm_page_bits(base, size);
1746 if (base == 0 && size == PAGE_SIZE) {
1747 /*pmap_clear_modify(m);*/
1748 vm_page_flag_clear(m, PG_NOSYNC);
1753 * Make the page all-dirty.
1755 * Also make sure the related object and vnode reflect the fact that the
1756 * object may now contain a dirty page.
1758 * Page must be busied?
1759 * No other requirements.
1762 vm_page_dirty(vm_page_t m)
1765 int pqtype = m->queue - m->pc;
1767 KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE,
1768 ("vm_page_dirty: page in free/cache queue!"));
1769 if (m->dirty != VM_PAGE_BITS_ALL) {
1770 m->dirty = VM_PAGE_BITS_ALL;
1772 vm_object_set_writeable_dirty(m->object);
1777 * Invalidates DEV_BSIZE'd chunks within a page. Both the
1778 * valid and dirty bits for the effected areas are cleared.
1780 * Page must be busied?
1782 * No other requirements.
1785 vm_page_set_invalid(vm_page_t m, int base, int size)
1789 bits = vm_page_bits(base, size);
1792 m->object->generation++;
1796 * The kernel assumes that the invalid portions of a page contain
1797 * garbage, but such pages can be mapped into memory by user code.
1798 * When this occurs, we must zero out the non-valid portions of the
1799 * page so user code sees what it expects.
1801 * Pages are most often semi-valid when the end of a file is mapped
1802 * into memory and the file's size is not page aligned.
1804 * Page must be busied?
1805 * No other requirements.
1808 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
1814 * Scan the valid bits looking for invalid sections that
1815 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the
1816 * valid bit may be set ) have already been zerod by
1817 * vm_page_set_validclean().
1819 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
1820 if (i == (PAGE_SIZE / DEV_BSIZE) ||
1821 (m->valid & (1 << i))
1824 pmap_zero_page_area(
1827 (i - b) << DEV_BSHIFT
1835 * setvalid is TRUE when we can safely set the zero'd areas
1836 * as being valid. We can do this if there are no cache consistency
1837 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS.
1840 m->valid = VM_PAGE_BITS_ALL;
1844 * Is a (partial) page valid? Note that the case where size == 0
1845 * will return FALSE in the degenerate case where the page is entirely
1846 * invalid, and TRUE otherwise.
1849 * No other requirements.
1852 vm_page_is_valid(vm_page_t m, int base, int size)
1854 int bits = vm_page_bits(base, size);
1856 if (m->valid && ((m->valid & bits) == bits))
1863 * update dirty bits from pmap/mmu. May not block.
1865 * Caller must hold vm_token if non-blocking operation desired.
1866 * No other requirements.
1869 vm_page_test_dirty(vm_page_t m)
1871 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) {
1877 * Issue an event on a VM page. Corresponding action structures are
1878 * removed from the page's list and called.
1881 vm_page_event_internal(vm_page_t m, vm_page_event_t event)
1883 struct vm_page_action *scan, *next;
1885 LIST_FOREACH_MUTABLE(scan, &m->action_list, entry, next) {
1886 if (scan->event == event) {
1887 scan->event = VMEVENT_NONE;
1888 LIST_REMOVE(scan, entry);
1889 scan->func(m, scan);
1895 #include "opt_ddb.h"
1897 #include <sys/kernel.h>
1899 #include <ddb/ddb.h>
1901 DB_SHOW_COMMAND(page, vm_page_print_page_info)
1903 db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count);
1904 db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count);
1905 db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count);
1906 db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count);
1907 db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count);
1908 db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved);
1909 db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min);
1910 db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target);
1911 db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min);
1912 db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target);
1915 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
1918 db_printf("PQ_FREE:");
1919 for(i=0;i<PQ_L2_SIZE;i++) {
1920 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt);
1924 db_printf("PQ_CACHE:");
1925 for(i=0;i<PQ_L2_SIZE;i++) {
1926 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt);
1930 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n",
1931 vm_page_queues[PQ_ACTIVE].lcnt,
1932 vm_page_queues[PQ_INACTIVE].lcnt);