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>
80 #include <sys/kernel.h>
83 #include <vm/vm_param.h>
85 #include <vm/vm_kern.h>
87 #include <vm/vm_map.h>
88 #include <vm/vm_object.h>
89 #include <vm/vm_page.h>
90 #include <vm/vm_pageout.h>
91 #include <vm/vm_pager.h>
92 #include <vm/vm_extern.h>
93 #include <vm/swap_pager.h>
95 #include <machine/md_var.h>
97 #include <vm/vm_page2.h>
98 #include <sys/mplock2.h>
100 #define VMACTION_HSIZE 256
101 #define VMACTION_HMASK (VMACTION_HSIZE - 1)
103 static void vm_page_queue_init(void);
104 static void vm_page_free_wakeup(void);
105 static vm_page_t vm_page_select_cache(vm_object_t, vm_pindex_t);
106 static vm_page_t _vm_page_list_find2(int basequeue, int index);
108 struct vpgqueues vm_page_queues[PQ_COUNT]; /* Array of tailq lists */
110 LIST_HEAD(vm_page_action_list, vm_page_action);
111 struct vm_page_action_list action_list[VMACTION_HSIZE];
112 static volatile int vm_pages_waiting;
115 #define ASSERT_IN_CRIT_SECTION() KKASSERT(crit_test(curthread));
117 RB_GENERATE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare,
118 vm_pindex_t, pindex);
121 vm_page_queue_init(void)
125 for (i = 0; i < PQ_L2_SIZE; i++)
126 vm_page_queues[PQ_FREE+i].cnt = &vmstats.v_free_count;
127 for (i = 0; i < PQ_L2_SIZE; i++)
128 vm_page_queues[PQ_CACHE+i].cnt = &vmstats.v_cache_count;
130 vm_page_queues[PQ_INACTIVE].cnt = &vmstats.v_inactive_count;
131 vm_page_queues[PQ_ACTIVE].cnt = &vmstats.v_active_count;
132 vm_page_queues[PQ_HOLD].cnt = &vmstats.v_active_count;
133 /* PQ_NONE has no queue */
135 for (i = 0; i < PQ_COUNT; i++)
136 TAILQ_INIT(&vm_page_queues[i].pl);
138 for (i = 0; i < VMACTION_HSIZE; i++)
139 LIST_INIT(&action_list[i]);
143 * note: place in initialized data section? Is this necessary?
146 int vm_page_array_size = 0;
147 int vm_page_zero_count = 0;
148 vm_page_t vm_page_array = 0;
153 * Sets the page size, perhaps based upon the memory size.
154 * Must be called before any use of page-size dependent functions.
157 vm_set_page_size(void)
159 if (vmstats.v_page_size == 0)
160 vmstats.v_page_size = PAGE_SIZE;
161 if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0)
162 panic("vm_set_page_size: page size not a power of two");
168 * Add a new page to the freelist for use by the system. New pages
169 * are added to both the head and tail of the associated free page
170 * queue in a bottom-up fashion, so both zero'd and non-zero'd page
171 * requests pull 'recent' adds (higher physical addresses) first.
173 * Must be called in a critical section.
176 vm_add_new_page(vm_paddr_t pa)
178 struct vpgqueues *vpq;
181 ++vmstats.v_page_count;
182 ++vmstats.v_free_count;
183 m = PHYS_TO_VM_PAGE(pa);
186 m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK;
187 m->queue = m->pc + PQ_FREE;
188 KKASSERT(m->dirty == 0);
190 vpq = &vm_page_queues[m->queue];
192 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq);
194 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq);
195 vpq->flipflop = 1 - vpq->flipflop;
197 vm_page_queues[m->queue].lcnt++;
204 * Initializes the resident memory module.
206 * Allocates memory for the page cells, and for the object/offset-to-page
207 * hash table headers. Each page cell is initialized and placed on the
210 * starta/enda represents the range of physical memory addresses available
211 * for use (skipping memory already used by the kernel), subject to
212 * phys_avail[]. Note that phys_avail[] has already mapped out memory
213 * already in use by the kernel.
216 vm_page_startup(vm_offset_t vaddr)
220 vm_paddr_t page_range;
227 vm_paddr_t biggestone, biggestsize;
234 vaddr = round_page(vaddr);
236 for (i = 0; phys_avail[i + 1]; i += 2) {
237 phys_avail[i] = round_page64(phys_avail[i]);
238 phys_avail[i + 1] = trunc_page64(phys_avail[i + 1]);
241 for (i = 0; phys_avail[i + 1]; i += 2) {
242 vm_paddr_t size = phys_avail[i + 1] - phys_avail[i];
244 if (size > biggestsize) {
252 end = phys_avail[biggestone+1];
253 end = trunc_page(end);
256 * Initialize the queue headers for the free queue, the active queue
257 * and the inactive queue.
260 vm_page_queue_init();
262 /* VKERNELs don't support minidumps and as such don't need vm_page_dump */
263 #if !defined(_KERNEL_VIRTUAL)
265 * Allocate a bitmap to indicate that a random physical page
266 * needs to be included in a minidump.
268 * The amd64 port needs this to indicate which direct map pages
269 * need to be dumped, via calls to dump_add_page()/dump_drop_page().
271 * However, i386 still needs this workspace internally within the
272 * minidump code. In theory, they are not needed on i386, but are
273 * included should the sf_buf code decide to use them.
275 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE;
276 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY);
277 end -= vm_page_dump_size;
278 vm_page_dump = (void *)pmap_map(&vaddr, end, end + vm_page_dump_size,
279 VM_PROT_READ | VM_PROT_WRITE);
280 bzero((void *)vm_page_dump, vm_page_dump_size);
284 * Compute the number of pages of memory that will be available for
285 * use (taking into account the overhead of a page structure per
288 first_page = phys_avail[0] / PAGE_SIZE;
289 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page;
290 npages = (total - (page_range * sizeof(struct vm_page))) / PAGE_SIZE;
293 * Initialize the mem entry structures now, and put them in the free
296 new_end = trunc_page(end - page_range * sizeof(struct vm_page));
297 mapped = pmap_map(&vaddr, new_end, end,
298 VM_PROT_READ | VM_PROT_WRITE);
299 vm_page_array = (vm_page_t)mapped;
301 #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL)
303 * since pmap_map on amd64 returns stuff out of a direct-map region,
304 * we have to manually add these pages to the minidump tracking so
305 * that they can be dumped, including the vm_page_array.
307 for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE)
312 * Clear all of the page structures
314 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page));
315 vm_page_array_size = page_range;
318 * Construct the free queue(s) in ascending order (by physical
319 * address) so that the first 16MB of physical memory is allocated
320 * last rather than first. On large-memory machines, this avoids
321 * the exhaustion of low physical memory before isa_dmainit has run.
323 vmstats.v_page_count = 0;
324 vmstats.v_free_count = 0;
325 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) {
330 last_pa = phys_avail[i + 1];
331 while (pa < last_pa && npages-- > 0) {
340 * Scan comparison function for Red-Black tree scans. An inclusive
341 * (start,end) is expected. Other fields are not used.
344 rb_vm_page_scancmp(struct vm_page *p, void *data)
346 struct rb_vm_page_scan_info *info = data;
348 if (p->pindex < info->start_pindex)
350 if (p->pindex > info->end_pindex)
356 rb_vm_page_compare(struct vm_page *p1, struct vm_page *p2)
358 if (p1->pindex < p2->pindex)
360 if (p1->pindex > p2->pindex)
366 * Holding a page keeps it from being reused. Other parts of the system
367 * can still disassociate the page from its current object and free it, or
368 * perform read or write I/O on it and/or otherwise manipulate the page,
369 * but if the page is held the VM system will leave the page and its data
370 * intact and not reuse the page for other purposes until the last hold
371 * reference is released. (see vm_page_wire() if you want to prevent the
372 * page from being disassociated from its object too).
374 * The caller must hold vm_token.
376 * The caller must still validate the contents of the page and, if necessary,
377 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete
378 * before manipulating the page.
381 vm_page_hold(vm_page_t m)
383 ASSERT_LWKT_TOKEN_HELD(&vm_token);
388 * The opposite of vm_page_hold(). A page can be freed while being held,
389 * which places it on the PQ_HOLD queue. We must call vm_page_free_toq()
390 * in this case to actually free it once the hold count drops to 0.
392 * The caller must hold vm_token if non-blocking operation is desired,
393 * but otherwise does not need to.
396 vm_page_unhold(vm_page_t m)
398 lwkt_gettoken(&vm_token);
400 KASSERT(m->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!"));
401 if (m->hold_count == 0 && m->queue == PQ_HOLD) {
405 lwkt_reltoken(&vm_token);
409 * Inserts the given vm_page into the object and object list.
411 * The pagetables are not updated but will presumably fault the page
412 * in if necessary, or if a kernel page the caller will at some point
413 * enter the page into the kernel's pmap. We are not allowed to block
414 * here so we *can't* do this anyway.
416 * This routine may not block.
417 * This routine must be called with the vm_token held.
418 * This routine must be called with a critical section held.
421 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
423 ASSERT_IN_CRIT_SECTION();
424 ASSERT_LWKT_TOKEN_HELD(&vm_token);
425 if (m->object != NULL)
426 panic("vm_page_insert: already inserted");
429 * Record the object/offset pair in this page
435 * Insert it into the object.
437 vm_page_rb_tree_RB_INSERT(&object->rb_memq, m);
438 object->generation++;
441 * show that the object has one more resident page.
443 object->resident_page_count++;
446 * Add the pv_list_cout of the page when its inserted in
449 object->agg_pv_list_count = object->agg_pv_list_count + m->md.pv_list_count;
452 * Since we are inserting a new and possibly dirty page,
453 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags.
455 if ((m->valid & m->dirty) || (m->flags & PG_WRITEABLE))
456 vm_object_set_writeable_dirty(object);
459 * Checks for a swap assignment and sets PG_SWAPPED if appropriate.
461 swap_pager_page_inserted(m);
465 * Removes the given vm_page_t from the global (object,index) hash table
466 * and from the object's memq.
468 * The underlying pmap entry (if any) is NOT removed here.
469 * This routine may not block.
471 * The page must be BUSY and will remain BUSY on return.
472 * No other requirements.
474 * NOTE: FreeBSD side effect was to unbusy the page on return. We leave
478 vm_page_remove(vm_page_t m)
483 lwkt_gettoken(&vm_token);
484 if (m->object == NULL) {
485 lwkt_reltoken(&vm_token);
490 if ((m->flags & PG_BUSY) == 0)
491 panic("vm_page_remove: page not busy");
496 * Remove the page from the object and update the object.
498 vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m);
499 object->resident_page_count--;
500 object->agg_pv_list_count = object->agg_pv_list_count - m->md.pv_list_count;
501 object->generation++;
504 lwkt_reltoken(&vm_token);
509 * Locate and return the page at (object, pindex), or NULL if the
510 * page could not be found.
512 * The caller must hold vm_token.
515 vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
520 * Search the hash table for this object/offset pair
522 ASSERT_LWKT_TOKEN_HELD(&vm_token);
524 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
526 KKASSERT(m == NULL || (m->object == object && m->pindex == pindex));
533 * Move the given memory entry from its current object to the specified
534 * target object/offset.
536 * The object must be locked.
537 * This routine may not block.
539 * Note: This routine will raise itself to splvm(), the caller need not.
541 * Note: Swap associated with the page must be invalidated by the move. We
542 * have to do this for several reasons: (1) we aren't freeing the
543 * page, (2) we are dirtying the page, (3) the VM system is probably
544 * moving the page from object A to B, and will then later move
545 * the backing store from A to B and we can't have a conflict.
547 * Note: We *always* dirty the page. It is necessary both for the
548 * fact that we moved it, and because we may be invalidating
549 * swap. If the page is on the cache, we have to deactivate it
550 * or vm_page_dirty() will panic. Dirty pages are not allowed
554 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
557 lwkt_gettoken(&vm_token);
559 vm_page_insert(m, new_object, new_pindex);
560 if (m->queue - m->pc == PQ_CACHE)
561 vm_page_deactivate(m);
564 lwkt_reltoken(&vm_token);
569 * vm_page_unqueue() without any wakeup. This routine is used when a page
570 * is being moved between queues or otherwise is to remain BUSYied by the
573 * The caller must hold vm_token
574 * This routine may not block.
577 vm_page_unqueue_nowakeup(vm_page_t m)
579 int queue = m->queue;
580 struct vpgqueues *pq;
582 ASSERT_LWKT_TOKEN_HELD(&vm_token);
583 if (queue != PQ_NONE) {
584 pq = &vm_page_queues[queue];
586 TAILQ_REMOVE(&pq->pl, m, pageq);
593 * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon
596 * The caller must hold vm_token
597 * This routine may not block.
600 vm_page_unqueue(vm_page_t m)
602 int queue = m->queue;
603 struct vpgqueues *pq;
605 ASSERT_LWKT_TOKEN_HELD(&vm_token);
606 if (queue != PQ_NONE) {
608 pq = &vm_page_queues[queue];
609 TAILQ_REMOVE(&pq->pl, m, pageq);
612 if ((queue - m->pc) == PQ_CACHE || (queue - m->pc) == PQ_FREE)
618 * vm_page_list_find()
620 * Find a page on the specified queue with color optimization.
622 * The page coloring optimization attempts to locate a page that does
623 * not overload other nearby pages in the object in the cpu's L1 or L2
624 * caches. We need this optimization because cpu caches tend to be
625 * physical caches, while object spaces tend to be virtual.
627 * Must be called with vm_token held.
628 * This routine may not block.
630 * Note that this routine is carefully inlined. A non-inlined version
631 * is available for outside callers but the only critical path is
632 * from within this source file.
636 _vm_page_list_find(int basequeue, int index, boolean_t prefer_zero)
641 m = TAILQ_LAST(&vm_page_queues[basequeue+index].pl, pglist);
643 m = TAILQ_FIRST(&vm_page_queues[basequeue+index].pl);
645 m = _vm_page_list_find2(basequeue, index);
650 _vm_page_list_find2(int basequeue, int index)
654 struct vpgqueues *pq;
656 pq = &vm_page_queues[basequeue];
659 * Note that for the first loop, index+i and index-i wind up at the
660 * same place. Even though this is not totally optimal, we've already
661 * blown it by missing the cache case so we do not care.
664 for(i = PQ_L2_SIZE / 2; i > 0; --i) {
665 if ((m = TAILQ_FIRST(&pq[(index + i) & PQ_L2_MASK].pl)) != NULL)
668 if ((m = TAILQ_FIRST(&pq[(index - i) & PQ_L2_MASK].pl)) != NULL)
675 * Must be called with vm_token held if the caller desired non-blocking
676 * operation and a stable result.
679 vm_page_list_find(int basequeue, int index, boolean_t prefer_zero)
681 return(_vm_page_list_find(basequeue, index, prefer_zero));
685 * Find a page on the cache queue with color optimization. As pages
686 * might be found, but not applicable, they are deactivated. This
687 * keeps us from using potentially busy cached pages.
689 * This routine may not block.
690 * Must be called with vm_token held.
693 vm_page_select_cache(vm_object_t object, vm_pindex_t pindex)
697 ASSERT_LWKT_TOKEN_HELD(&vm_token);
699 m = _vm_page_list_find(
701 (pindex + object->pg_color) & PQ_L2_MASK,
704 if (m && ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy ||
705 m->hold_count || m->wire_count)) {
706 vm_page_deactivate(m);
715 * Find a free or zero page, with specified preference. We attempt to
716 * inline the nominal case and fall back to _vm_page_select_free()
719 * This routine must be called with a critical section held.
720 * This routine may not block.
722 static __inline vm_page_t
723 vm_page_select_free(vm_object_t object, vm_pindex_t pindex, boolean_t prefer_zero)
727 m = _vm_page_list_find(
729 (pindex + object->pg_color) & PQ_L2_MASK,
738 * Allocate and return a memory cell associated with this VM object/offset
743 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain
744 * VM_ALLOC_QUICK like normal but cannot use cache
745 * VM_ALLOC_SYSTEM greater free drain
746 * VM_ALLOC_INTERRUPT allow free list to be completely drained
747 * VM_ALLOC_ZERO advisory request for pre-zero'd page
749 * The object must be locked.
750 * This routine may not block.
751 * The returned page will be marked PG_BUSY
753 * Additional special handling is required when called from an interrupt
754 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache
758 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req)
763 lwkt_gettoken(&vm_token);
765 KKASSERT(object != NULL);
766 KASSERT(!vm_page_lookup(object, pindex),
767 ("vm_page_alloc: page already allocated"));
769 (VM_ALLOC_NORMAL|VM_ALLOC_QUICK|
770 VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
773 * Certain system threads (pageout daemon, buf_daemon's) are
774 * allowed to eat deeper into the free page list.
776 if (curthread->td_flags & TDF_SYSTHREAD)
777 page_req |= VM_ALLOC_SYSTEM;
780 if (vmstats.v_free_count > vmstats.v_free_reserved ||
781 ((page_req & VM_ALLOC_INTERRUPT) && vmstats.v_free_count > 0) ||
782 ((page_req & VM_ALLOC_SYSTEM) && vmstats.v_cache_count == 0 &&
783 vmstats.v_free_count > vmstats.v_interrupt_free_min)
786 * The free queue has sufficient free pages to take one out.
788 if (page_req & VM_ALLOC_ZERO)
789 m = vm_page_select_free(object, pindex, TRUE);
791 m = vm_page_select_free(object, pindex, FALSE);
792 } else if (page_req & VM_ALLOC_NORMAL) {
794 * Allocatable from the cache (non-interrupt only). On
795 * success, we must free the page and try again, thus
796 * ensuring that vmstats.v_*_free_min counters are replenished.
799 if (curthread->td_preempted) {
800 kprintf("vm_page_alloc(): warning, attempt to allocate"
801 " cache page from preempting interrupt\n");
804 m = vm_page_select_cache(object, pindex);
807 m = vm_page_select_cache(object, pindex);
810 * On success move the page into the free queue and loop.
813 KASSERT(m->dirty == 0,
814 ("Found dirty cache page %p", m));
816 vm_page_protect(m, VM_PROT_NONE);
822 * On failure return NULL
824 lwkt_reltoken(&vm_token);
826 #if defined(DIAGNOSTIC)
827 if (vmstats.v_cache_count > 0)
828 kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats.v_cache_count);
830 vm_pageout_deficit++;
835 * No pages available, wakeup the pageout daemon and give up.
837 lwkt_reltoken(&vm_token);
839 vm_pageout_deficit++;
845 * Good page found. The page has not yet been busied. We are in
846 * a critical section.
848 KASSERT(m != NULL, ("vm_page_alloc(): missing page on free queue\n"));
849 KASSERT(m->dirty == 0,
850 ("vm_page_alloc: free/cache page %p was dirty", m));
853 * Remove from free queue
855 vm_page_unqueue_nowakeup(m);
858 * Initialize structure. Only the PG_ZERO flag is inherited. Set
861 if (m->flags & PG_ZERO) {
862 vm_page_zero_count--;
863 m->flags = PG_ZERO | PG_BUSY;
874 * vm_page_insert() is safe prior to the crit_exit(). Note also that
875 * inserting a page here does not insert it into the pmap (which
876 * could cause us to block allocating memory). We cannot block
879 vm_page_insert(m, object, pindex);
882 * Don't wakeup too often - wakeup the pageout daemon when
883 * we would be nearly out of memory.
887 lwkt_reltoken(&vm_token);
891 * A PG_BUSY page is returned.
897 * Wait for sufficient free memory for nominal heavy memory use kernel
901 vm_wait_nominal(void)
903 while (vm_page_count_min(0))
908 * Test if vm_wait_nominal() would block.
911 vm_test_nominal(void)
913 if (vm_page_count_min(0))
919 * Block until free pages are available for allocation, called in various
920 * places before memory allocations.
922 * The caller may loop if vm_page_count_min() == FALSE so we cannot be
923 * more generous then that.
933 lwkt_gettoken(&vm_token);
935 if (curthread == pagethread) {
937 * The pageout daemon itself needs pages, this is bad.
939 if (vm_page_count_min(0)) {
940 vm_pageout_pages_needed = 1;
941 tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo);
945 * Wakeup the pageout daemon if necessary and wait.
947 if (vm_page_count_target()) {
948 if (vm_pages_needed == 0) {
950 wakeup(&vm_pages_needed);
952 ++vm_pages_waiting; /* SMP race ok */
953 tsleep(&vmstats.v_free_count, 0, "vmwait", timo);
956 lwkt_reltoken(&vm_token);
960 * Block until free pages are available for allocation
962 * Called only from vm_fault so that processes page faulting can be
969 * Wakeup the pageout daemon if necessary and wait.
971 if (vm_page_count_target()) {
972 lwkt_gettoken(&vm_token);
973 if (vm_page_count_target()) {
974 if (vm_pages_needed == 0) {
976 wakeup(&vm_pages_needed);
978 ++vm_pages_waiting; /* SMP race ok */
979 tsleep(&vmstats.v_free_count, 0, "pfault", hz);
981 lwkt_reltoken(&vm_token);
986 * Put the specified page on the active list (if appropriate). Ensure
987 * that act_count is at least ACT_INIT but do not otherwise mess with it.
989 * The page queues must be locked.
990 * This routine may not block.
993 vm_page_activate(vm_page_t m)
996 lwkt_gettoken(&vm_token);
997 if (m->queue != PQ_ACTIVE) {
998 if ((m->queue - m->pc) == PQ_CACHE)
999 mycpu->gd_cnt.v_reactivated++;
1003 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
1004 m->queue = PQ_ACTIVE;
1005 vm_page_queues[PQ_ACTIVE].lcnt++;
1006 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl,
1008 if (m->act_count < ACT_INIT)
1009 m->act_count = ACT_INIT;
1010 vmstats.v_active_count++;
1013 if (m->act_count < ACT_INIT)
1014 m->act_count = ACT_INIT;
1016 lwkt_reltoken(&vm_token);
1021 * Helper routine for vm_page_free_toq() and vm_page_cache(). This
1022 * routine is called when a page has been added to the cache or free
1025 * This routine may not block.
1026 * This routine must be called at splvm()
1028 static __inline void
1029 vm_page_free_wakeup(void)
1032 * If the pageout daemon itself needs pages, then tell it that
1033 * there are some free.
1035 if (vm_pageout_pages_needed &&
1036 vmstats.v_cache_count + vmstats.v_free_count >=
1037 vmstats.v_pageout_free_min
1039 wakeup(&vm_pageout_pages_needed);
1040 vm_pageout_pages_needed = 0;
1044 * Wakeup processes that are waiting on memory.
1046 * NOTE: vm_paging_target() is the pageout daemon's target, while
1047 * vm_page_count_target() is somewhere inbetween. We want
1048 * to wake processes up prior to the pageout daemon reaching
1049 * its target to provide some hysteresis.
1051 if (vm_pages_waiting) {
1052 if (!vm_page_count_target()) {
1054 * Plenty of pages are free, wakeup everyone.
1056 vm_pages_waiting = 0;
1057 wakeup(&vmstats.v_free_count);
1058 ++mycpu->gd_cnt.v_ppwakeups;
1059 } else if (!vm_page_count_min(0)) {
1061 * Some pages are free, wakeup someone.
1063 int wcount = vm_pages_waiting;
1066 vm_pages_waiting = wcount;
1067 wakeup_one(&vmstats.v_free_count);
1068 ++mycpu->gd_cnt.v_ppwakeups;
1076 * Returns the given page to the PQ_FREE list, disassociating it with
1079 * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on
1080 * return (the page will have been freed). No particular spl is required
1083 * This routine may not block.
1086 vm_page_free_toq(vm_page_t m)
1088 struct vpgqueues *pq;
1091 lwkt_gettoken(&vm_token);
1092 mycpu->gd_cnt.v_tfree++;
1094 KKASSERT((m->flags & PG_MAPPED) == 0);
1096 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) {
1098 "vm_page_free: pindex(%lu), busy(%d), PG_BUSY(%d), hold(%d)\n",
1099 (u_long)m->pindex, m->busy, (m->flags & PG_BUSY) ? 1 : 0,
1101 if ((m->queue - m->pc) == PQ_FREE)
1102 panic("vm_page_free: freeing free page");
1104 panic("vm_page_free: freeing busy page");
1108 * unqueue, then remove page. Note that we cannot destroy
1109 * the page here because we do not want to call the pager's
1110 * callback routine until after we've put the page on the
1111 * appropriate free queue.
1113 vm_page_unqueue_nowakeup(m);
1117 * No further management of fictitious pages occurs beyond object
1118 * and queue removal.
1120 if ((m->flags & PG_FICTITIOUS) != 0) {
1122 lwkt_reltoken(&vm_token);
1130 if (m->wire_count != 0) {
1131 if (m->wire_count > 1) {
1133 "vm_page_free: invalid wire count (%d), pindex: 0x%lx",
1134 m->wire_count, (long)m->pindex);
1136 panic("vm_page_free: freeing wired page");
1140 * Clear the UNMANAGED flag when freeing an unmanaged page.
1142 if (m->flags & PG_UNMANAGED) {
1143 m->flags &= ~PG_UNMANAGED;
1146 if (m->hold_count != 0) {
1147 m->flags &= ~PG_ZERO;
1150 m->queue = PQ_FREE + m->pc;
1152 pq = &vm_page_queues[m->queue];
1157 * Put zero'd pages on the end ( where we look for zero'd pages
1158 * first ) and non-zerod pages at the head.
1160 if (m->flags & PG_ZERO) {
1161 TAILQ_INSERT_TAIL(&pq->pl, m, pageq);
1162 ++vm_page_zero_count;
1164 TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
1167 vm_page_free_wakeup();
1168 lwkt_reltoken(&vm_token);
1173 * vm_page_free_fromq_fast()
1175 * Remove a non-zero page from one of the free queues; the page is removed for
1176 * zeroing, so do not issue a wakeup.
1181 vm_page_free_fromq_fast(void)
1188 lwkt_gettoken(&vm_token);
1189 for (i = 0; i < PQ_L2_SIZE; ++i) {
1190 m = vm_page_list_find(PQ_FREE, qi, FALSE);
1191 qi = (qi + PQ_PRIME2) & PQ_L2_MASK;
1192 if (m && (m->flags & PG_ZERO) == 0) {
1193 vm_page_unqueue_nowakeup(m);
1199 lwkt_reltoken(&vm_token);
1205 * vm_page_unmanage()
1207 * Prevent PV management from being done on the page. The page is
1208 * removed from the paging queues as if it were wired, and as a
1209 * consequence of no longer being managed the pageout daemon will not
1210 * touch it (since there is no way to locate the pte mappings for the
1211 * page). madvise() calls that mess with the pmap will also no longer
1212 * operate on the page.
1214 * Beyond that the page is still reasonably 'normal'. Freeing the page
1215 * will clear the flag.
1217 * This routine is used by OBJT_PHYS objects - objects using unswappable
1218 * physical memory as backing store rather then swap-backed memory and
1219 * will eventually be extended to support 4MB unmanaged physical
1222 * Must be called with a critical section held.
1223 * Must be called with vm_token held.
1226 vm_page_unmanage(vm_page_t m)
1228 ASSERT_IN_CRIT_SECTION();
1229 ASSERT_LWKT_TOKEN_HELD(&vm_token);
1230 if ((m->flags & PG_UNMANAGED) == 0) {
1231 if (m->wire_count == 0)
1234 vm_page_flag_set(m, PG_UNMANAGED);
1238 * Mark this page as wired down by yet another map, removing it from
1239 * paging queues as necessary.
1241 * The page queues must be locked.
1242 * This routine may not block.
1245 vm_page_wire(vm_page_t m)
1248 * Only bump the wire statistics if the page is not already wired,
1249 * and only unqueue the page if it is on some queue (if it is unmanaged
1250 * it is already off the queues). Don't do anything with fictitious
1251 * pages because they are always wired.
1254 lwkt_gettoken(&vm_token);
1255 if ((m->flags & PG_FICTITIOUS) == 0) {
1256 if (m->wire_count == 0) {
1257 if ((m->flags & PG_UNMANAGED) == 0)
1259 vmstats.v_wire_count++;
1262 KASSERT(m->wire_count != 0,
1263 ("vm_page_wire: wire_count overflow m=%p", m));
1265 lwkt_reltoken(&vm_token);
1270 * Release one wiring of this page, potentially enabling it to be paged again.
1272 * Many pages placed on the inactive queue should actually go
1273 * into the cache, but it is difficult to figure out which. What
1274 * we do instead, if the inactive target is well met, is to put
1275 * clean pages at the head of the inactive queue instead of the tail.
1276 * This will cause them to be moved to the cache more quickly and
1277 * if not actively re-referenced, freed more quickly. If we just
1278 * stick these pages at the end of the inactive queue, heavy filesystem
1279 * meta-data accesses can cause an unnecessary paging load on memory bound
1280 * processes. This optimization causes one-time-use metadata to be
1281 * reused more quickly.
1283 * BUT, if we are in a low-memory situation we have no choice but to
1284 * put clean pages on the cache queue.
1286 * A number of routines use vm_page_unwire() to guarantee that the page
1287 * will go into either the inactive or active queues, and will NEVER
1288 * be placed in the cache - for example, just after dirtying a page.
1289 * dirty pages in the cache are not allowed.
1291 * The page queues must be locked.
1292 * This routine may not block.
1295 vm_page_unwire(vm_page_t m, int activate)
1298 lwkt_gettoken(&vm_token);
1299 if (m->flags & PG_FICTITIOUS) {
1301 } else if (m->wire_count <= 0) {
1302 panic("vm_page_unwire: invalid wire count: %d", m->wire_count);
1304 if (--m->wire_count == 0) {
1305 --vmstats.v_wire_count;
1306 if (m->flags & PG_UNMANAGED) {
1308 } else if (activate) {
1310 &vm_page_queues[PQ_ACTIVE].pl, m, pageq);
1311 m->queue = PQ_ACTIVE;
1312 vm_page_queues[PQ_ACTIVE].lcnt++;
1313 vmstats.v_active_count++;
1315 vm_page_flag_clear(m, PG_WINATCFLS);
1317 &vm_page_queues[PQ_INACTIVE].pl, m, pageq);
1318 m->queue = PQ_INACTIVE;
1319 vm_page_queues[PQ_INACTIVE].lcnt++;
1320 vmstats.v_inactive_count++;
1321 ++vm_swapcache_inactive_heuristic;
1325 lwkt_reltoken(&vm_token);
1331 * Move the specified page to the inactive queue. If the page has
1332 * any associated swap, the swap is deallocated.
1334 * Normally athead is 0 resulting in LRU operation. athead is set
1335 * to 1 if we want this page to be 'as if it were placed in the cache',
1336 * except without unmapping it from the process address space.
1338 * This routine may not block.
1339 * The caller must hold vm_token.
1341 static __inline void
1342 _vm_page_deactivate(vm_page_t m, int athead)
1345 * Ignore if already inactive.
1347 if (m->queue == PQ_INACTIVE)
1350 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
1351 if ((m->queue - m->pc) == PQ_CACHE)
1352 mycpu->gd_cnt.v_reactivated++;
1353 vm_page_flag_clear(m, PG_WINATCFLS);
1356 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl,
1359 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl,
1361 ++vm_swapcache_inactive_heuristic;
1363 m->queue = PQ_INACTIVE;
1364 vm_page_queues[PQ_INACTIVE].lcnt++;
1365 vmstats.v_inactive_count++;
1370 * Attempt to deactivate a page.
1375 vm_page_deactivate(vm_page_t m)
1378 lwkt_gettoken(&vm_token);
1379 _vm_page_deactivate(m, 0);
1380 lwkt_reltoken(&vm_token);
1385 * Attempt to move a page to PQ_CACHE.
1386 * Returns 0 on failure, 1 on success
1391 vm_page_try_to_cache(vm_page_t m)
1394 lwkt_gettoken(&vm_token);
1395 if (m->dirty || m->hold_count || m->busy || m->wire_count ||
1396 (m->flags & (PG_BUSY|PG_UNMANAGED))) {
1397 lwkt_reltoken(&vm_token);
1401 vm_page_test_dirty(m);
1403 lwkt_reltoken(&vm_token);
1408 lwkt_reltoken(&vm_token);
1414 * Attempt to free the page. If we cannot free it, we do nothing.
1415 * 1 is returned on success, 0 on failure.
1420 vm_page_try_to_free(vm_page_t m)
1423 lwkt_gettoken(&vm_token);
1424 if (m->dirty || m->hold_count || m->busy || m->wire_count ||
1425 (m->flags & (PG_BUSY|PG_UNMANAGED))) {
1426 lwkt_reltoken(&vm_token);
1430 vm_page_test_dirty(m);
1432 lwkt_reltoken(&vm_token);
1437 vm_page_protect(m, VM_PROT_NONE);
1439 lwkt_reltoken(&vm_token);
1447 * Put the specified page onto the page cache queue (if appropriate).
1449 * The caller must hold vm_token.
1450 * This routine may not block.
1453 vm_page_cache(vm_page_t m)
1455 ASSERT_IN_CRIT_SECTION();
1456 ASSERT_LWKT_TOKEN_HELD(&vm_token);
1458 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy ||
1459 m->wire_count || m->hold_count) {
1460 kprintf("vm_page_cache: attempting to cache busy/held page\n");
1465 * Already in the cache (and thus not mapped)
1467 if ((m->queue - m->pc) == PQ_CACHE) {
1468 KKASSERT((m->flags & PG_MAPPED) == 0);
1473 * Caller is required to test m->dirty, but note that the act of
1474 * removing the page from its maps can cause it to become dirty
1475 * on an SMP system due to another cpu running in usermode.
1478 panic("vm_page_cache: caching a dirty page, pindex: %ld",
1483 * Remove all pmaps and indicate that the page is not
1484 * writeable or mapped. Our vm_page_protect() call may
1485 * have blocked (especially w/ VM_PROT_NONE), so recheck
1489 vm_page_protect(m, VM_PROT_NONE);
1491 if ((m->flags & (PG_BUSY|PG_UNMANAGED|PG_MAPPED)) || m->busy ||
1492 m->wire_count || m->hold_count) {
1494 } else if (m->dirty) {
1495 vm_page_deactivate(m);
1497 vm_page_unqueue_nowakeup(m);
1498 m->queue = PQ_CACHE + m->pc;
1499 vm_page_queues[m->queue].lcnt++;
1500 TAILQ_INSERT_TAIL(&vm_page_queues[m->queue].pl, m, pageq);
1501 vmstats.v_cache_count++;
1502 vm_page_free_wakeup();
1507 * vm_page_dontneed()
1509 * Cache, deactivate, or do nothing as appropriate. This routine
1510 * is typically used by madvise() MADV_DONTNEED.
1512 * Generally speaking we want to move the page into the cache so
1513 * it gets reused quickly. However, this can result in a silly syndrome
1514 * due to the page recycling too quickly. Small objects will not be
1515 * fully cached. On the otherhand, if we move the page to the inactive
1516 * queue we wind up with a problem whereby very large objects
1517 * unnecessarily blow away our inactive and cache queues.
1519 * The solution is to move the pages based on a fixed weighting. We
1520 * either leave them alone, deactivate them, or move them to the cache,
1521 * where moving them to the cache has the highest weighting.
1522 * By forcing some pages into other queues we eventually force the
1523 * system to balance the queues, potentially recovering other unrelated
1524 * space from active. The idea is to not force this to happen too
1530 vm_page_dontneed(vm_page_t m)
1532 static int dnweight;
1539 * occassionally leave the page alone
1542 lwkt_gettoken(&vm_token);
1543 if ((dnw & 0x01F0) == 0 ||
1544 m->queue == PQ_INACTIVE ||
1545 m->queue - m->pc == PQ_CACHE
1547 if (m->act_count >= ACT_INIT)
1549 lwkt_reltoken(&vm_token);
1555 vm_page_test_dirty(m);
1557 if (m->dirty || (dnw & 0x0070) == 0) {
1559 * Deactivate the page 3 times out of 32.
1564 * Cache the page 28 times out of every 32. Note that
1565 * the page is deactivated instead of cached, but placed
1566 * at the head of the queue instead of the tail.
1570 _vm_page_deactivate(m, head);
1571 lwkt_reltoken(&vm_token);
1576 * Grab a page, blocking if it is busy and allocating a page if necessary.
1577 * A busy page is returned or NULL.
1579 * If VM_ALLOC_RETRY is specified VM_ALLOC_NORMAL must also be specified.
1580 * If VM_ALLOC_RETRY is not specified
1582 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is
1583 * always returned if we had blocked.
1584 * This routine will never return NULL if VM_ALLOC_RETRY is set.
1585 * This routine may not be called from an interrupt.
1586 * The returned page may not be entirely valid.
1588 * This routine may be called from mainline code without spl protection and
1589 * be guarenteed a busied page associated with the object at the specified
1595 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
1600 KKASSERT(allocflags &
1601 (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
1603 lwkt_gettoken(&vm_token);
1605 if ((m = vm_page_lookup(object, pindex)) != NULL) {
1606 if (m->busy || (m->flags & PG_BUSY)) {
1607 generation = object->generation;
1609 while ((object->generation == generation) &&
1610 (m->busy || (m->flags & PG_BUSY))) {
1611 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED);
1612 tsleep(m, 0, "pgrbwt", 0);
1613 if ((allocflags & VM_ALLOC_RETRY) == 0) {
1624 m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY);
1627 if ((allocflags & VM_ALLOC_RETRY) == 0)
1632 lwkt_reltoken(&vm_token);
1638 * Mapping function for valid bits or for dirty bits in
1639 * a page. May not block.
1641 * Inputs are required to range within a page.
1647 vm_page_bits(int base, int size)
1653 base + size <= PAGE_SIZE,
1654 ("vm_page_bits: illegal base/size %d/%d", base, size)
1657 if (size == 0) /* handle degenerate case */
1660 first_bit = base >> DEV_BSHIFT;
1661 last_bit = (base + size - 1) >> DEV_BSHIFT;
1663 return ((2 << last_bit) - (1 << first_bit));
1667 * Sets portions of a page valid and clean. The arguments are expected
1668 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
1669 * of any partial chunks touched by the range. The invalid portion of
1670 * such chunks will be zero'd.
1672 * NOTE: When truncating a buffer vnode_pager_setsize() will automatically
1673 * align base to DEV_BSIZE so as not to mark clean a partially
1674 * truncated device block. Otherwise the dirty page status might be
1677 * This routine may not block.
1679 * (base + size) must be less then or equal to PAGE_SIZE.
1682 _vm_page_zero_valid(vm_page_t m, int base, int size)
1687 if (size == 0) /* handle degenerate case */
1691 * If the base is not DEV_BSIZE aligned and the valid
1692 * bit is clear, we have to zero out a portion of the
1696 if ((frag = base & ~(DEV_BSIZE - 1)) != base &&
1697 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0
1699 pmap_zero_page_area(
1707 * If the ending offset is not DEV_BSIZE aligned and the
1708 * valid bit is clear, we have to zero out a portion of
1712 endoff = base + size;
1714 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff &&
1715 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0
1717 pmap_zero_page_area(
1720 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))
1726 * Set valid, clear dirty bits. If validating the entire
1727 * page we can safely clear the pmap modify bit. We also
1728 * use this opportunity to clear the PG_NOSYNC flag. If a process
1729 * takes a write fault on a MAP_NOSYNC memory area the flag will
1732 * We set valid bits inclusive of any overlap, but we can only
1733 * clear dirty bits for DEV_BSIZE chunks that are fully within
1736 * Page must be busied?
1737 * No other requirements.
1740 vm_page_set_valid(vm_page_t m, int base, int size)
1742 _vm_page_zero_valid(m, base, size);
1743 m->valid |= vm_page_bits(base, size);
1748 * Set valid bits and clear dirty bits.
1750 * NOTE: This function does not clear the pmap modified bit.
1751 * Also note that e.g. NFS may use a byte-granular base
1754 * Page must be busied?
1755 * No other requirements.
1758 vm_page_set_validclean(vm_page_t m, int base, int size)
1762 _vm_page_zero_valid(m, base, size);
1763 pagebits = vm_page_bits(base, size);
1764 m->valid |= pagebits;
1765 m->dirty &= ~pagebits;
1766 if (base == 0 && size == PAGE_SIZE) {
1767 /*pmap_clear_modify(m);*/
1768 vm_page_flag_clear(m, PG_NOSYNC);
1773 * Set valid & dirty. Used by buwrite()
1775 * Page must be busied?
1776 * No other requirements.
1779 vm_page_set_validdirty(vm_page_t m, int base, int size)
1783 pagebits = vm_page_bits(base, size);
1784 m->valid |= pagebits;
1785 m->dirty |= pagebits;
1787 vm_object_set_writeable_dirty(m->object);
1793 * NOTE: This function does not clear the pmap modified bit.
1794 * Also note that e.g. NFS may use a byte-granular base
1797 * Page must be busied?
1798 * No other requirements.
1801 vm_page_clear_dirty(vm_page_t m, int base, int size)
1803 m->dirty &= ~vm_page_bits(base, size);
1804 if (base == 0 && size == PAGE_SIZE) {
1805 /*pmap_clear_modify(m);*/
1806 vm_page_flag_clear(m, PG_NOSYNC);
1811 * Make the page all-dirty.
1813 * Also make sure the related object and vnode reflect the fact that the
1814 * object may now contain a dirty page.
1816 * Page must be busied?
1817 * No other requirements.
1820 vm_page_dirty(vm_page_t m)
1823 int pqtype = m->queue - m->pc;
1825 KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE,
1826 ("vm_page_dirty: page in free/cache queue!"));
1827 if (m->dirty != VM_PAGE_BITS_ALL) {
1828 m->dirty = VM_PAGE_BITS_ALL;
1830 vm_object_set_writeable_dirty(m->object);
1835 * Invalidates DEV_BSIZE'd chunks within a page. Both the
1836 * valid and dirty bits for the effected areas are cleared.
1838 * Page must be busied?
1840 * No other requirements.
1843 vm_page_set_invalid(vm_page_t m, int base, int size)
1847 bits = vm_page_bits(base, size);
1850 m->object->generation++;
1854 * The kernel assumes that the invalid portions of a page contain
1855 * garbage, but such pages can be mapped into memory by user code.
1856 * When this occurs, we must zero out the non-valid portions of the
1857 * page so user code sees what it expects.
1859 * Pages are most often semi-valid when the end of a file is mapped
1860 * into memory and the file's size is not page aligned.
1862 * Page must be busied?
1863 * No other requirements.
1866 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
1872 * Scan the valid bits looking for invalid sections that
1873 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the
1874 * valid bit may be set ) have already been zerod by
1875 * vm_page_set_validclean().
1877 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
1878 if (i == (PAGE_SIZE / DEV_BSIZE) ||
1879 (m->valid & (1 << i))
1882 pmap_zero_page_area(
1885 (i - b) << DEV_BSHIFT
1893 * setvalid is TRUE when we can safely set the zero'd areas
1894 * as being valid. We can do this if there are no cache consistency
1895 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS.
1898 m->valid = VM_PAGE_BITS_ALL;
1902 * Is a (partial) page valid? Note that the case where size == 0
1903 * will return FALSE in the degenerate case where the page is entirely
1904 * invalid, and TRUE otherwise.
1907 * No other requirements.
1910 vm_page_is_valid(vm_page_t m, int base, int size)
1912 int bits = vm_page_bits(base, size);
1914 if (m->valid && ((m->valid & bits) == bits))
1921 * update dirty bits from pmap/mmu. May not block.
1923 * Caller must hold vm_token if non-blocking operation desired.
1924 * No other requirements.
1927 vm_page_test_dirty(vm_page_t m)
1929 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) {
1935 * Register an action, associating it with its vm_page
1938 vm_page_register_action(vm_page_action_t action, vm_page_event_t event)
1940 struct vm_page_action_list *list;
1943 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK;
1944 list = &action_list[hv];
1946 lwkt_gettoken(&vm_token);
1947 vm_page_flag_set(action->m, PG_ACTIONLIST);
1948 action->event = event;
1949 LIST_INSERT_HEAD(list, action, entry);
1950 lwkt_reltoken(&vm_token);
1954 * Unregister an action, disassociating it from its related vm_page
1957 vm_page_unregister_action(vm_page_action_t action)
1959 struct vm_page_action_list *list;
1962 lwkt_gettoken(&vm_token);
1963 if (action->event != VMEVENT_NONE) {
1964 action->event = VMEVENT_NONE;
1965 LIST_REMOVE(action, entry);
1967 hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK;
1968 list = &action_list[hv];
1969 if (LIST_EMPTY(list))
1970 vm_page_flag_clear(action->m, PG_ACTIONLIST);
1972 lwkt_reltoken(&vm_token);
1976 * Issue an event on a VM page. Corresponding action structures are
1977 * removed from the page's list and called.
1979 * If the vm_page has no more pending action events we clear its
1980 * PG_ACTIONLIST flag.
1983 vm_page_event_internal(vm_page_t m, vm_page_event_t event)
1985 struct vm_page_action_list *list;
1986 struct vm_page_action *scan;
1987 struct vm_page_action *next;
1991 hv = (int)((intptr_t)m >> 8) & VMACTION_HMASK;
1992 list = &action_list[hv];
1995 lwkt_gettoken(&vm_token);
1996 LIST_FOREACH_MUTABLE(scan, list, entry, next) {
1998 if (scan->event == event) {
1999 scan->event = VMEVENT_NONE;
2000 LIST_REMOVE(scan, entry);
2001 scan->func(m, scan);
2009 vm_page_flag_clear(m, PG_ACTIONLIST);
2010 lwkt_reltoken(&vm_token);
2014 #include "opt_ddb.h"
2016 #include <sys/kernel.h>
2018 #include <ddb/ddb.h>
2020 DB_SHOW_COMMAND(page, vm_page_print_page_info)
2022 db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count);
2023 db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count);
2024 db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count);
2025 db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count);
2026 db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count);
2027 db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved);
2028 db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min);
2029 db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target);
2030 db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min);
2031 db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target);
2034 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
2037 db_printf("PQ_FREE:");
2038 for(i=0;i<PQ_L2_SIZE;i++) {
2039 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt);
2043 db_printf("PQ_CACHE:");
2044 for(i=0;i<PQ_L2_SIZE;i++) {
2045 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt);
2049 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n",
2050 vm_page_queues[PQ_ACTIVE].lcnt,
2051 vm_page_queues[PQ_INACTIVE].lcnt);