2 * Copyright (c) 1991 Regents of the University of California.
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91
33 * $FreeBSD: src/sys/vm/vm_page.c,v 1.147.2.18 2002/03/10 05:03:19 alc Exp $
37 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
38 * All rights reserved.
40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
42 * Permission to use, copy, modify and distribute this software and
43 * its documentation is hereby granted, provided that both the copyright
44 * notice and this permission notice appear in all copies of the
45 * software, derivative works or modified versions, and any portions
46 * thereof, and that both notices appear in supporting documentation.
48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
52 * Carnegie Mellon requests users of this software to return to
54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
55 * School of Computer Science
56 * Carnegie Mellon University
57 * Pittsburgh PA 15213-3890
59 * any improvements or extensions that they make and grant Carnegie the
60 * rights to redistribute these changes.
63 * Resident memory management module. The module manipulates 'VM pages'.
64 * A VM page is the core building block for memory management.
67 #include <sys/param.h>
68 #include <sys/systm.h>
69 #include <sys/malloc.h>
71 #include <sys/vmmeter.h>
72 #include <sys/vnode.h>
73 #include <sys/kernel.h>
74 #include <sys/alist.h>
75 #include <sys/sysctl.h>
76 #include <sys/cpu_topology.h>
79 #include <vm/vm_param.h>
81 #include <vm/vm_kern.h>
83 #include <vm/vm_map.h>
84 #include <vm/vm_object.h>
85 #include <vm/vm_page.h>
86 #include <vm/vm_pageout.h>
87 #include <vm/vm_pager.h>
88 #include <vm/vm_extern.h>
89 #include <vm/swap_pager.h>
91 #include <machine/inttypes.h>
92 #include <machine/md_var.h>
93 #include <machine/specialreg.h>
95 #include <vm/vm_page2.h>
96 #include <sys/spinlock2.h>
99 * SET - Minimum required set associative size, must be a power of 2. We
100 * want this to match or exceed the set-associativeness of the cpu.
102 * GRP - A larger set that allows bleed-over into the domains of other
103 * nearby cpus. Also must be a power of 2. Used by the page zeroing
104 * code to smooth things out a bit.
106 #define PQ_SET_ASSOC 16
107 #define PQ_SET_ASSOC_MASK (PQ_SET_ASSOC - 1)
109 #define PQ_GRP_ASSOC (PQ_SET_ASSOC * 2)
110 #define PQ_GRP_ASSOC_MASK (PQ_GRP_ASSOC - 1)
112 static void vm_page_queue_init(void);
113 static void vm_page_free_wakeup(void);
114 static vm_page_t vm_page_select_cache(u_short pg_color);
115 static vm_page_t _vm_page_list_find2(int basequeue, int index);
116 static void _vm_page_deactivate_locked(vm_page_t m, int athead);
119 * Array of tailq lists
121 __cachealign struct vpgqueues vm_page_queues[PQ_COUNT];
123 static volatile int vm_pages_waiting;
124 static struct alist vm_contig_alist;
125 static struct almeta vm_contig_ameta[ALIST_RECORDS_65536];
126 static struct spinlock vm_contig_spin = SPINLOCK_INITIALIZER(&vm_contig_spin, "vm_contig_spin");
128 static u_long vm_dma_reserved = 0;
129 TUNABLE_ULONG("vm.dma_reserved", &vm_dma_reserved);
130 SYSCTL_ULONG(_vm, OID_AUTO, dma_reserved, CTLFLAG_RD, &vm_dma_reserved, 0,
131 "Memory reserved for DMA");
132 SYSCTL_UINT(_vm, OID_AUTO, dma_free_pages, CTLFLAG_RD,
133 &vm_contig_alist.bl_free, 0, "Memory reserved for DMA");
135 static int vm_contig_verbose = 0;
136 TUNABLE_INT("vm.contig_verbose", &vm_contig_verbose);
138 RB_GENERATE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare,
139 vm_pindex_t, pindex);
142 vm_page_queue_init(void)
146 for (i = 0; i < PQ_L2_SIZE; i++)
147 vm_page_queues[PQ_FREE+i].cnt_offset =
148 offsetof(struct vmstats, v_free_count);
149 for (i = 0; i < PQ_L2_SIZE; i++)
150 vm_page_queues[PQ_CACHE+i].cnt_offset =
151 offsetof(struct vmstats, v_cache_count);
152 for (i = 0; i < PQ_L2_SIZE; i++)
153 vm_page_queues[PQ_INACTIVE+i].cnt_offset =
154 offsetof(struct vmstats, v_inactive_count);
155 for (i = 0; i < PQ_L2_SIZE; i++)
156 vm_page_queues[PQ_ACTIVE+i].cnt_offset =
157 offsetof(struct vmstats, v_active_count);
158 for (i = 0; i < PQ_L2_SIZE; i++)
159 vm_page_queues[PQ_HOLD+i].cnt_offset =
160 offsetof(struct vmstats, v_active_count);
161 /* PQ_NONE has no queue */
163 for (i = 0; i < PQ_COUNT; i++) {
164 TAILQ_INIT(&vm_page_queues[i].pl);
165 spin_init(&vm_page_queues[i].spin, "vm_page_queue_init");
170 * note: place in initialized data section? Is this necessary?
173 int vm_page_array_size = 0;
174 vm_page_t vm_page_array = NULL;
175 vm_paddr_t vm_low_phys_reserved;
180 * Sets the page size, perhaps based upon the memory size.
181 * Must be called before any use of page-size dependent functions.
184 vm_set_page_size(void)
186 if (vmstats.v_page_size == 0)
187 vmstats.v_page_size = PAGE_SIZE;
188 if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0)
189 panic("vm_set_page_size: page size not a power of two");
195 * Add a new page to the freelist for use by the system. New pages
196 * are added to both the head and tail of the associated free page
197 * queue in a bottom-up fashion, so both zero'd and non-zero'd page
198 * requests pull 'recent' adds (higher physical addresses) first.
200 * Beware that the page zeroing daemon will also be running soon after
201 * boot, moving pages from the head to the tail of the PQ_FREE queues.
203 * Must be called in a critical section.
206 vm_add_new_page(vm_paddr_t pa)
208 struct vpgqueues *vpq;
211 m = PHYS_TO_VM_PAGE(pa);
214 m->pat_mode = PAT_WRITE_BACK;
215 m->pc = (pa >> PAGE_SHIFT);
218 * Twist for cpu localization in addition to page coloring, so
219 * different cpus selecting by m->queue get different page colors.
221 m->pc ^= ((pa >> PAGE_SHIFT) / PQ_L2_SIZE);
222 m->pc ^= ((pa >> PAGE_SHIFT) / (PQ_L2_SIZE * PQ_L2_SIZE));
226 * Reserve a certain number of contiguous low memory pages for
227 * contigmalloc() to use.
229 if (pa < vm_low_phys_reserved) {
230 atomic_add_int(&vmstats.v_page_count, 1);
231 atomic_add_int(&vmstats.v_dma_pages, 1);
234 atomic_add_int(&vmstats.v_wire_count, 1);
235 alist_free(&vm_contig_alist, pa >> PAGE_SHIFT, 1);
242 m->queue = m->pc + PQ_FREE;
243 KKASSERT(m->dirty == 0);
245 atomic_add_int(&vmstats.v_page_count, 1);
246 atomic_add_int(&vmstats.v_free_count, 1);
247 vpq = &vm_page_queues[m->queue];
248 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq);
255 * Initializes the resident memory module.
257 * Preallocates memory for critical VM structures and arrays prior to
258 * kernel_map becoming available.
260 * Memory is allocated from (virtual2_start, virtual2_end) if available,
261 * otherwise memory is allocated from (virtual_start, virtual_end).
263 * On x86-64 (virtual_start, virtual_end) is only 2GB and may not be
264 * large enough to hold vm_page_array & other structures for machines with
265 * large amounts of ram, so we want to use virtual2* when available.
268 vm_page_startup(void)
270 vm_offset_t vaddr = virtual2_start ? virtual2_start : virtual_start;
273 vm_paddr_t page_range;
279 vm_paddr_t biggestone, biggestsize;
286 vaddr = round_page(vaddr);
289 * Make sure ranges are page-aligned.
291 for (i = 0; phys_avail[i].phys_end; ++i) {
292 phys_avail[i].phys_beg = round_page64(phys_avail[i].phys_beg);
293 phys_avail[i].phys_end = trunc_page64(phys_avail[i].phys_end);
294 if (phys_avail[i].phys_end < phys_avail[i].phys_beg)
295 phys_avail[i].phys_end = phys_avail[i].phys_beg;
299 * Locate largest block
301 for (i = 0; phys_avail[i].phys_end; ++i) {
302 vm_paddr_t size = phys_avail[i].phys_end -
303 phys_avail[i].phys_beg;
305 if (size > biggestsize) {
311 --i; /* adjust to last entry for use down below */
313 end = phys_avail[biggestone].phys_end;
314 end = trunc_page(end);
317 * Initialize the queue headers for the free queue, the active queue
318 * and the inactive queue.
320 vm_page_queue_init();
322 #if !defined(_KERNEL_VIRTUAL)
324 * VKERNELs don't support minidumps and as such don't need
327 * Allocate a bitmap to indicate that a random physical page
328 * needs to be included in a minidump.
330 * The amd64 port needs this to indicate which direct map pages
331 * need to be dumped, via calls to dump_add_page()/dump_drop_page().
333 * However, i386 still needs this workspace internally within the
334 * minidump code. In theory, they are not needed on i386, but are
335 * included should the sf_buf code decide to use them.
337 page_range = phys_avail[i].phys_end / PAGE_SIZE;
338 vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY);
339 end -= vm_page_dump_size;
340 vm_page_dump = (void *)pmap_map(&vaddr, end, end + vm_page_dump_size,
341 VM_PROT_READ | VM_PROT_WRITE);
342 bzero((void *)vm_page_dump, vm_page_dump_size);
345 * Compute the number of pages of memory that will be available for
346 * use (taking into account the overhead of a page structure per
349 first_page = phys_avail[0].phys_beg / PAGE_SIZE;
350 page_range = phys_avail[i].phys_end / PAGE_SIZE - first_page;
351 npages = (total - (page_range * sizeof(struct vm_page))) / PAGE_SIZE;
353 #ifndef _KERNEL_VIRTUAL
355 * (only applies to real kernels)
357 * Reserve a large amount of low memory for potential 32-bit DMA
358 * space allocations. Once device initialization is complete we
359 * release most of it, but keep (vm_dma_reserved) memory reserved
360 * for later use. Typically for X / graphics. Through trial and
361 * error we find that GPUs usually requires ~60-100MB or so.
363 * By default, 128M is left in reserve on machines with 2G+ of ram.
365 vm_low_phys_reserved = (vm_paddr_t)65536 << PAGE_SHIFT;
366 if (vm_low_phys_reserved > total / 4)
367 vm_low_phys_reserved = total / 4;
368 if (vm_dma_reserved == 0) {
369 vm_dma_reserved = 128 * 1024 * 1024; /* 128MB */
370 if (vm_dma_reserved > total / 16)
371 vm_dma_reserved = total / 16;
374 alist_init(&vm_contig_alist, 65536, vm_contig_ameta,
375 ALIST_RECORDS_65536);
378 * Initialize the mem entry structures now, and put them in the free
381 new_end = trunc_page(end - page_range * sizeof(struct vm_page));
382 mapped = pmap_map(&vaddr, new_end, end, VM_PROT_READ | VM_PROT_WRITE);
383 vm_page_array = (vm_page_t)mapped;
385 #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL)
387 * since pmap_map on amd64 returns stuff out of a direct-map region,
388 * we have to manually add these pages to the minidump tracking so
389 * that they can be dumped, including the vm_page_array.
392 pa < phys_avail[biggestone].phys_end;
399 * Clear all of the page structures, run basic initialization so
400 * PHYS_TO_VM_PAGE() operates properly even on pages not in the
403 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page));
404 vm_page_array_size = page_range;
406 m = &vm_page_array[0];
407 pa = ptoa(first_page);
408 for (i = 0; i < page_range; ++i) {
409 spin_init(&m->spin, "vm_page");
416 * Construct the free queue(s) in ascending order (by physical
417 * address) so that the first 16MB of physical memory is allocated
418 * last rather than first. On large-memory machines, this avoids
419 * the exhaustion of low physical memory before isa_dmainit has run.
421 vmstats.v_page_count = 0;
422 vmstats.v_free_count = 0;
423 for (i = 0; phys_avail[i].phys_end && npages > 0; ++i) {
424 pa = phys_avail[i].phys_beg;
428 last_pa = phys_avail[i].phys_end;
429 while (pa < last_pa && npages-- > 0) {
435 virtual2_start = vaddr;
437 virtual_start = vaddr;
438 mycpu->gd_vmstats = vmstats;
442 * Reorganize VM pages based on numa data. May be called as many times as
443 * necessary. Will reorganize the vm_page_t page color and related queue(s)
444 * to allow vm_page_alloc() to choose pages based on socket affinity.
446 * NOTE: This function is only called while we are still in UP mode, so
447 * we only need a critical section to protect the queues (which
448 * saves a lot of time, there are likely a ton of pages).
451 vm_numa_organize(vm_paddr_t ran_beg, vm_paddr_t bytes, int physid)
456 struct vpgqueues *vpq;
464 * Check if no physical information, or there was only one socket
465 * (so don't waste time doing nothing!).
467 if (cpu_topology_phys_ids <= 1 ||
468 cpu_topology_core_ids == 0) {
473 * Setup for our iteration. Note that ACPI may iterate CPU
474 * sockets starting at 0 or 1 or some other number. The
475 * cpu_topology code mod's it against the socket count.
477 ran_end = ran_beg + bytes;
478 physid %= cpu_topology_phys_ids;
480 socket_mod = PQ_L2_SIZE / cpu_topology_phys_ids;
481 socket_value = physid * socket_mod;
482 mend = &vm_page_array[vm_page_array_size];
487 * Adjust vm_page->pc and requeue all affected pages. The
488 * allocator will then be able to localize memory allocations
491 for (i = 0; phys_avail[i].phys_end; ++i) {
492 scan_beg = phys_avail[i].phys_beg;
493 scan_end = phys_avail[i].phys_end;
494 if (scan_end <= ran_beg)
496 if (scan_beg >= ran_end)
498 if (scan_beg < ran_beg)
500 if (scan_end > ran_end)
502 if (atop(scan_end) > first_page + vm_page_array_size)
503 scan_end = ptoa(first_page + vm_page_array_size);
505 m = PHYS_TO_VM_PAGE(scan_beg);
506 while (scan_beg < scan_end) {
508 if (m->queue != PQ_NONE) {
509 vpq = &vm_page_queues[m->queue];
510 TAILQ_REMOVE(&vpq->pl, m, pageq);
512 /* queue doesn't change, no need to adj cnt */
515 m->pc += socket_value;
518 vpq = &vm_page_queues[m->queue];
519 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq);
521 /* queue doesn't change, no need to adj cnt */
524 m->pc += socket_value;
527 scan_beg += PAGE_SIZE;
535 * We tended to reserve a ton of memory for contigmalloc(). Now that most
536 * drivers have initialized we want to return most the remaining free
537 * reserve back to the VM page queues so they can be used for normal
540 * We leave vm_dma_reserved bytes worth of free pages in the reserve pool.
543 vm_page_startup_finish(void *dummy __unused)
552 spin_lock(&vm_contig_spin);
554 bfree = alist_free_info(&vm_contig_alist, &blk, &count);
555 if (bfree <= vm_dma_reserved / PAGE_SIZE)
561 * Figure out how much of the initial reserve we have to
562 * free in order to reach our target.
564 bfree -= vm_dma_reserved / PAGE_SIZE;
566 blk += count - bfree;
571 * Calculate the nearest power of 2 <= count.
573 for (xcount = 1; xcount <= count; xcount <<= 1)
576 blk += count - xcount;
580 * Allocate the pages from the alist, then free them to
581 * the normal VM page queues.
583 * Pages allocated from the alist are wired. We have to
584 * busy, unwire, and free them. We must also adjust
585 * vm_low_phys_reserved before freeing any pages to prevent
588 rblk = alist_alloc(&vm_contig_alist, blk, count);
590 kprintf("vm_page_startup_finish: Unable to return "
591 "dma space @0x%08x/%d -> 0x%08x\n",
595 atomic_add_int(&vmstats.v_dma_pages, -count);
596 spin_unlock(&vm_contig_spin);
598 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT);
599 vm_low_phys_reserved = VM_PAGE_TO_PHYS(m);
601 vm_page_busy_wait(m, FALSE, "cpgfr");
602 vm_page_unwire(m, 0);
607 spin_lock(&vm_contig_spin);
609 spin_unlock(&vm_contig_spin);
612 * Print out how much DMA space drivers have already allocated and
613 * how much is left over.
615 kprintf("DMA space used: %jdk, remaining available: %jdk\n",
616 (intmax_t)(vmstats.v_dma_pages - vm_contig_alist.bl_free) *
618 (intmax_t)vm_contig_alist.bl_free * (PAGE_SIZE / 1024));
620 SYSINIT(vm_pgend, SI_SUB_PROC0_POST, SI_ORDER_ANY,
621 vm_page_startup_finish, NULL);
625 * Scan comparison function for Red-Black tree scans. An inclusive
626 * (start,end) is expected. Other fields are not used.
629 rb_vm_page_scancmp(struct vm_page *p, void *data)
631 struct rb_vm_page_scan_info *info = data;
633 if (p->pindex < info->start_pindex)
635 if (p->pindex > info->end_pindex)
641 rb_vm_page_compare(struct vm_page *p1, struct vm_page *p2)
643 if (p1->pindex < p2->pindex)
645 if (p1->pindex > p2->pindex)
651 vm_page_init(vm_page_t m)
653 /* do nothing for now. Called from pmap_page_init() */
657 * Each page queue has its own spin lock, which is fairly optimal for
658 * allocating and freeing pages at least.
660 * The caller must hold the vm_page_spin_lock() before locking a vm_page's
661 * queue spinlock via this function. Also note that m->queue cannot change
662 * unless both the page and queue are locked.
666 _vm_page_queue_spin_lock(vm_page_t m)
671 if (queue != PQ_NONE) {
672 spin_lock(&vm_page_queues[queue].spin);
673 KKASSERT(queue == m->queue);
679 _vm_page_queue_spin_unlock(vm_page_t m)
685 if (queue != PQ_NONE)
686 spin_unlock(&vm_page_queues[queue].spin);
691 _vm_page_queues_spin_lock(u_short queue)
694 if (queue != PQ_NONE)
695 spin_lock(&vm_page_queues[queue].spin);
701 _vm_page_queues_spin_unlock(u_short queue)
704 if (queue != PQ_NONE)
705 spin_unlock(&vm_page_queues[queue].spin);
709 vm_page_queue_spin_lock(vm_page_t m)
711 _vm_page_queue_spin_lock(m);
715 vm_page_queues_spin_lock(u_short queue)
717 _vm_page_queues_spin_lock(queue);
721 vm_page_queue_spin_unlock(vm_page_t m)
723 _vm_page_queue_spin_unlock(m);
727 vm_page_queues_spin_unlock(u_short queue)
729 _vm_page_queues_spin_unlock(queue);
733 * This locks the specified vm_page and its queue in the proper order
734 * (page first, then queue). The queue may change so the caller must
739 _vm_page_and_queue_spin_lock(vm_page_t m)
741 vm_page_spin_lock(m);
742 _vm_page_queue_spin_lock(m);
747 _vm_page_and_queue_spin_unlock(vm_page_t m)
749 _vm_page_queues_spin_unlock(m->queue);
750 vm_page_spin_unlock(m);
754 vm_page_and_queue_spin_unlock(vm_page_t m)
756 _vm_page_and_queue_spin_unlock(m);
760 vm_page_and_queue_spin_lock(vm_page_t m)
762 _vm_page_and_queue_spin_lock(m);
766 * Helper function removes vm_page from its current queue.
767 * Returns the base queue the page used to be on.
769 * The vm_page and the queue must be spinlocked.
770 * This function will unlock the queue but leave the page spinlocked.
772 static __inline u_short
773 _vm_page_rem_queue_spinlocked(vm_page_t m)
775 struct vpgqueues *pq;
781 if (queue != PQ_NONE) {
782 pq = &vm_page_queues[queue];
783 TAILQ_REMOVE(&pq->pl, m, pageq);
786 * Adjust our pcpu stats. In order for the nominal low-memory
787 * algorithms to work properly we don't let any pcpu stat get
788 * too negative before we force it to be rolled-up into the
789 * global stats. Otherwise our pageout and vm_wait tests
792 * The idea here is to reduce unnecessary SMP cache
793 * mastership changes in the global vmstats, which can be
794 * particularly bad in multi-socket systems.
796 cnt = (int *)((char *)&mycpu->gd_vmstats_adj + pq->cnt_offset);
797 atomic_add_int(cnt, -1);
798 if (*cnt < -VMMETER_SLOP_COUNT) {
799 u_int copy = atomic_swap_int(cnt, 0);
800 cnt = (int *)((char *)&vmstats + pq->cnt_offset);
801 atomic_add_int(cnt, copy);
802 cnt = (int *)((char *)&mycpu->gd_vmstats +
804 atomic_add_int(cnt, copy);
810 vm_page_queues_spin_unlock(oqueue); /* intended */
816 * Helper function places the vm_page on the specified queue. Generally
817 * speaking only PQ_FREE pages are placed at the head, to allow them to
818 * be allocated sooner rather than later on the assumption that they
821 * The vm_page must be spinlocked.
822 * This function will return with both the page and the queue locked.
825 _vm_page_add_queue_spinlocked(vm_page_t m, u_short queue, int athead)
827 struct vpgqueues *pq;
830 KKASSERT(m->queue == PQ_NONE);
832 if (queue != PQ_NONE) {
833 vm_page_queues_spin_lock(queue);
834 pq = &vm_page_queues[queue];
838 * Adjust our pcpu stats. If a system entity really needs
839 * to incorporate the count it will call vmstats_rollup()
840 * to roll it all up into the global vmstats strufture.
842 cnt = (int *)((char *)&mycpu->gd_vmstats_adj + pq->cnt_offset);
843 atomic_add_int(cnt, 1);
846 * PQ_FREE is always handled LIFO style to try to provide
847 * cache-hot pages to programs.
850 if (queue - m->pc == PQ_FREE) {
851 TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
853 TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
855 TAILQ_INSERT_TAIL(&pq->pl, m, pageq);
857 /* leave the queue spinlocked */
862 * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE)
863 * m->busy is zero. Returns TRUE if it had to sleep, FALSE if we
864 * did not. Only one sleep call will be made before returning.
866 * This function does NOT busy the page and on return the page is not
867 * guaranteed to be available.
870 vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg)
878 if ((flags & PG_BUSY) == 0 &&
879 (also_m_busy == 0 || (flags & PG_SBUSY) == 0)) {
882 tsleep_interlock(m, 0);
883 if (atomic_cmpset_int(&m->flags, flags,
884 flags | PG_WANTED | PG_REFERENCED)) {
885 tsleep(m, PINTERLOCKED, msg, 0);
892 * This calculates and returns a page color given an optional VM object and
893 * either a pindex or an iterator. We attempt to return a cpu-localized
894 * pg_color that is still roughly 16-way set-associative. The CPU topology
895 * is used if it was probed.
897 * The caller may use the returned value to index into e.g. PQ_FREE when
898 * allocating a page in order to nominally obtain pages that are hopefully
899 * already localized to the requesting cpu. This function is not able to
900 * provide any sort of guarantee of this, but does its best to improve
901 * hardware cache management performance.
903 * WARNING! The caller must mask the returned value with PQ_L2_MASK.
906 vm_get_pg_color(int cpuid, vm_object_t object, vm_pindex_t pindex)
913 phys_id = get_cpu_phys_id(cpuid);
914 core_id = get_cpu_core_id(cpuid);
915 object_pg_color = object ? object->pg_color : 0;
917 if (cpu_topology_phys_ids && cpu_topology_core_ids) {
921 * Break us down by socket and cpu
923 pg_color = phys_id * PQ_L2_SIZE / cpu_topology_phys_ids;
924 pg_color += core_id * PQ_L2_SIZE /
925 (cpu_topology_core_ids * cpu_topology_phys_ids);
928 * Calculate remaining component for object/queue color
930 grpsize = PQ_L2_SIZE / (cpu_topology_core_ids *
931 cpu_topology_phys_ids);
933 pg_color += (pindex + object_pg_color) % grpsize;
938 /* 3->9, 4->8, 5->10, 6->12, 7->14 */
943 pg_color += (pindex + object_pg_color) % grpsize;
947 * Unknown topology, distribute things evenly.
949 pg_color = cpuid * PQ_L2_SIZE / ncpus;
950 pg_color += pindex + object_pg_color;
952 return (pg_color & PQ_L2_MASK);
956 * Wait until PG_BUSY can be set, then set it. If also_m_busy is TRUE we
957 * also wait for m->busy to become 0 before setting PG_BUSY.
960 VM_PAGE_DEBUG_EXT(vm_page_busy_wait)(vm_page_t m,
961 int also_m_busy, const char *msg
969 if (flags & PG_BUSY) {
970 tsleep_interlock(m, 0);
971 if (atomic_cmpset_int(&m->flags, flags,
972 flags | PG_WANTED | PG_REFERENCED)) {
973 tsleep(m, PINTERLOCKED, msg, 0);
975 } else if (also_m_busy && (flags & PG_SBUSY)) {
976 tsleep_interlock(m, 0);
977 if (atomic_cmpset_int(&m->flags, flags,
978 flags | PG_WANTED | PG_REFERENCED)) {
979 tsleep(m, PINTERLOCKED, msg, 0);
982 if (atomic_cmpset_int(&m->flags, flags,
986 m->busy_line = lineno;
995 * Attempt to set PG_BUSY. If also_m_busy is TRUE we only succeed if m->busy
998 * Returns non-zero on failure.
1001 VM_PAGE_DEBUG_EXT(vm_page_busy_try)(vm_page_t m, int also_m_busy
1009 if (flags & PG_BUSY)
1011 if (also_m_busy && (flags & PG_SBUSY))
1013 if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) {
1014 #ifdef VM_PAGE_DEBUG
1015 m->busy_func = func;
1016 m->busy_line = lineno;
1024 * Clear the PG_BUSY flag and return non-zero to indicate to the caller
1025 * that a wakeup() should be performed.
1027 * The vm_page must be spinlocked and will remain spinlocked on return.
1028 * The related queue must NOT be spinlocked (which could deadlock us).
1034 _vm_page_wakeup(vm_page_t m)
1041 if (atomic_cmpset_int(&m->flags, flags,
1042 flags & ~(PG_BUSY | PG_WANTED))) {
1046 return(flags & PG_WANTED);
1050 * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This
1051 * is typically the last call you make on a page before moving onto
1055 vm_page_wakeup(vm_page_t m)
1057 KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!"));
1058 vm_page_spin_lock(m);
1059 if (_vm_page_wakeup(m)) {
1060 vm_page_spin_unlock(m);
1063 vm_page_spin_unlock(m);
1068 * Holding a page keeps it from being reused. Other parts of the system
1069 * can still disassociate the page from its current object and free it, or
1070 * perform read or write I/O on it and/or otherwise manipulate the page,
1071 * but if the page is held the VM system will leave the page and its data
1072 * intact and not reuse the page for other purposes until the last hold
1073 * reference is released. (see vm_page_wire() if you want to prevent the
1074 * page from being disassociated from its object too).
1076 * The caller must still validate the contents of the page and, if necessary,
1077 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete
1078 * before manipulating the page.
1080 * XXX get vm_page_spin_lock() here and move FREE->HOLD if necessary
1083 vm_page_hold(vm_page_t m)
1085 vm_page_spin_lock(m);
1086 atomic_add_int(&m->hold_count, 1);
1087 if (m->queue - m->pc == PQ_FREE) {
1088 _vm_page_queue_spin_lock(m);
1089 _vm_page_rem_queue_spinlocked(m);
1090 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0);
1091 _vm_page_queue_spin_unlock(m);
1093 vm_page_spin_unlock(m);
1097 * The opposite of vm_page_hold(). If the page is on the HOLD queue
1098 * it was freed while held and must be moved back to the FREE queue.
1101 vm_page_unhold(vm_page_t m)
1103 KASSERT(m->hold_count > 0 && m->queue - m->pc != PQ_FREE,
1104 ("vm_page_unhold: pg %p illegal hold_count (%d) or on FREE queue (%d)",
1105 m, m->hold_count, m->queue - m->pc));
1106 vm_page_spin_lock(m);
1107 atomic_add_int(&m->hold_count, -1);
1108 if (m->hold_count == 0 && m->queue - m->pc == PQ_HOLD) {
1109 _vm_page_queue_spin_lock(m);
1110 _vm_page_rem_queue_spinlocked(m);
1111 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 1);
1112 _vm_page_queue_spin_unlock(m);
1114 vm_page_spin_unlock(m);
1120 * Create a fictitious page with the specified physical address and
1121 * memory attribute. The memory attribute is the only the machine-
1122 * dependent aspect of a fictitious page that must be initialized.
1126 vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
1129 if ((m->flags & PG_FICTITIOUS) != 0) {
1131 * The page's memattr might have changed since the
1132 * previous initialization. Update the pmap to the
1137 m->phys_addr = paddr;
1139 /* Fictitious pages don't use "segind". */
1140 /* Fictitious pages don't use "order" or "pool". */
1141 m->flags = PG_FICTITIOUS | PG_UNMANAGED | PG_BUSY;
1143 spin_init(&m->spin, "fake_page");
1146 pmap_page_set_memattr(m, memattr);
1150 * Inserts the given vm_page into the object and object list.
1152 * The pagetables are not updated but will presumably fault the page
1153 * in if necessary, or if a kernel page the caller will at some point
1154 * enter the page into the kernel's pmap. We are not allowed to block
1155 * here so we *can't* do this anyway.
1157 * This routine may not block.
1158 * This routine must be called with the vm_object held.
1159 * This routine must be called with a critical section held.
1161 * This routine returns TRUE if the page was inserted into the object
1162 * successfully, and FALSE if the page already exists in the object.
1165 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
1167 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(object));
1168 if (m->object != NULL)
1169 panic("vm_page_insert: already inserted");
1171 atomic_add_int(&object->generation, 1);
1174 * Record the object/offset pair in this page and add the
1175 * pv_list_count of the page to the object.
1177 * The vm_page spin lock is required for interactions with the pmap.
1179 vm_page_spin_lock(m);
1182 if (vm_page_rb_tree_RB_INSERT(&object->rb_memq, m)) {
1185 vm_page_spin_unlock(m);
1188 ++object->resident_page_count;
1189 ++mycpu->gd_vmtotal.t_rm;
1190 vm_page_spin_unlock(m);
1193 * Since we are inserting a new and possibly dirty page,
1194 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags.
1196 if ((m->valid & m->dirty) ||
1197 (m->flags & (PG_WRITEABLE | PG_NEED_COMMIT)))
1198 vm_object_set_writeable_dirty(object);
1201 * Checks for a swap assignment and sets PG_SWAPPED if appropriate.
1203 swap_pager_page_inserted(m);
1208 * Removes the given vm_page_t from the (object,index) table
1210 * The underlying pmap entry (if any) is NOT removed here.
1211 * This routine may not block.
1213 * The page must be BUSY and will remain BUSY on return.
1214 * No other requirements.
1216 * NOTE: FreeBSD side effect was to unbusy the page on return. We leave
1220 vm_page_remove(vm_page_t m)
1224 if (m->object == NULL) {
1228 if ((m->flags & PG_BUSY) == 0)
1229 panic("vm_page_remove: page not busy");
1233 vm_object_hold(object);
1236 * Remove the page from the object and update the object.
1238 * The vm_page spin lock is required for interactions with the pmap.
1240 vm_page_spin_lock(m);
1241 vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m);
1242 --object->resident_page_count;
1243 --mycpu->gd_vmtotal.t_rm;
1245 atomic_add_int(&object->generation, 1);
1246 vm_page_spin_unlock(m);
1248 vm_object_drop(object);
1252 * Locate and return the page at (object, pindex), or NULL if the
1253 * page could not be found.
1255 * The caller must hold the vm_object token.
1258 vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
1263 * Search the hash table for this object/offset pair
1265 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
1266 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
1267 KKASSERT(m == NULL || (m->object == object && m->pindex == pindex));
1272 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait)(struct vm_object *object,
1274 int also_m_busy, const char *msg
1280 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
1281 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
1283 KKASSERT(m->object == object && m->pindex == pindex);
1286 if (flags & PG_BUSY) {
1287 tsleep_interlock(m, 0);
1288 if (atomic_cmpset_int(&m->flags, flags,
1289 flags | PG_WANTED | PG_REFERENCED)) {
1290 tsleep(m, PINTERLOCKED, msg, 0);
1291 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq,
1294 } else if (also_m_busy && (flags & PG_SBUSY)) {
1295 tsleep_interlock(m, 0);
1296 if (atomic_cmpset_int(&m->flags, flags,
1297 flags | PG_WANTED | PG_REFERENCED)) {
1298 tsleep(m, PINTERLOCKED, msg, 0);
1299 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq,
1302 } else if (atomic_cmpset_int(&m->flags, flags,
1304 #ifdef VM_PAGE_DEBUG
1305 m->busy_func = func;
1306 m->busy_line = lineno;
1315 * Attempt to lookup and busy a page.
1317 * Returns NULL if the page could not be found
1319 * Returns a vm_page and error == TRUE if the page exists but could not
1322 * Returns a vm_page and error == FALSE on success.
1325 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try)(struct vm_object *object,
1327 int also_m_busy, int *errorp
1333 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object));
1334 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
1337 KKASSERT(m->object == object && m->pindex == pindex);
1340 if (flags & PG_BUSY) {
1344 if (also_m_busy && (flags & PG_SBUSY)) {
1348 if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) {
1349 #ifdef VM_PAGE_DEBUG
1350 m->busy_func = func;
1351 m->busy_line = lineno;
1360 * Attempt to repurpose the passed-in page. If the passed-in page cannot
1361 * be repurposed it will be released, *must_reenter will be set to 1, and
1362 * this function will fall-through to vm_page_lookup_busy_try().
1364 * The passed-in page must be wired and not busy. The returned page will
1365 * be busied and not wired.
1367 * A different page may be returned. The returned page will be busied and
1370 * NULL can be returned. If so, the required page could not be busied.
1371 * The passed-in page will be unwired.
1374 vm_page_repurpose(struct vm_object *object, vm_pindex_t pindex,
1375 int also_m_busy, int *errorp, vm_page_t m,
1376 int *must_reenter, int *iswired)
1380 * Do not mess with pages in a complex state, such as pages
1381 * which are mapped, as repurposing such pages can be more
1382 * expensive than simply allocatin a new one.
1384 * NOTE: Soft-busying can deadlock against putpages or I/O
1385 * so we only allow hard-busying here.
1387 KKASSERT(also_m_busy == FALSE);
1388 vm_page_busy_wait(m, also_m_busy, "biodep");
1390 if ((m->flags & (PG_UNMANAGED | PG_MAPPED |
1391 PG_FICTITIOUS | PG_SBUSY)) ||
1392 m->busy || m->wire_count != 1 || m->hold_count) {
1393 vm_page_unwire(m, 0);
1395 /* fall through to normal lookup */
1396 } else if (m->dirty || (m->flags & PG_NEED_COMMIT)) {
1397 vm_page_unwire(m, 0);
1398 vm_page_deactivate(m);
1400 /* fall through to normal lookup */
1403 * We can safely repurpose the page. It should
1404 * already be unqueued.
1406 KKASSERT(m->queue == PQ_NONE && m->dirty == 0);
1410 if (vm_page_insert(m, object, pindex)) {
1416 vm_page_unwire(m, 0);
1418 /* fall through to normal lookup */
1423 * Cannot repurpose page, attempt to locate the desired page. May
1428 m = vm_page_lookup_busy_try(object, pindex, also_m_busy, errorp);
1434 * Caller must hold the related vm_object
1437 vm_page_next(vm_page_t m)
1441 next = vm_page_rb_tree_RB_NEXT(m);
1442 if (next && next->pindex != m->pindex + 1)
1450 * Move the given vm_page from its current object to the specified
1451 * target object/offset. The page must be busy and will remain so
1454 * new_object must be held.
1455 * This routine might block. XXX ?
1457 * NOTE: Swap associated with the page must be invalidated by the move. We
1458 * have to do this for several reasons: (1) we aren't freeing the
1459 * page, (2) we are dirtying the page, (3) the VM system is probably
1460 * moving the page from object A to B, and will then later move
1461 * the backing store from A to B and we can't have a conflict.
1463 * NOTE: We *always* dirty the page. It is necessary both for the
1464 * fact that we moved it, and because we may be invalidating
1465 * swap. If the page is on the cache, we have to deactivate it
1466 * or vm_page_dirty() will panic. Dirty pages are not allowed
1470 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
1472 KKASSERT(m->flags & PG_BUSY);
1473 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(new_object));
1475 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(m->object));
1478 if (vm_page_insert(m, new_object, new_pindex) == FALSE) {
1479 panic("vm_page_rename: target exists (%p,%"PRIu64")",
1480 new_object, new_pindex);
1482 if (m->queue - m->pc == PQ_CACHE)
1483 vm_page_deactivate(m);
1488 * vm_page_unqueue() without any wakeup. This routine is used when a page
1489 * is to remain BUSYied by the caller.
1491 * This routine may not block.
1494 vm_page_unqueue_nowakeup(vm_page_t m)
1496 vm_page_and_queue_spin_lock(m);
1497 (void)_vm_page_rem_queue_spinlocked(m);
1498 vm_page_spin_unlock(m);
1502 * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon
1505 * This routine may not block.
1508 vm_page_unqueue(vm_page_t m)
1512 vm_page_and_queue_spin_lock(m);
1513 queue = _vm_page_rem_queue_spinlocked(m);
1514 if (queue == PQ_FREE || queue == PQ_CACHE) {
1515 vm_page_spin_unlock(m);
1516 pagedaemon_wakeup();
1518 vm_page_spin_unlock(m);
1523 * vm_page_list_find()
1525 * Find a page on the specified queue with color optimization.
1527 * The page coloring optimization attempts to locate a page that does
1528 * not overload other nearby pages in the object in the cpu's L1 or L2
1529 * caches. We need this optimization because cpu caches tend to be
1530 * physical caches, while object spaces tend to be virtual.
1532 * The page coloring optimization also, very importantly, tries to localize
1533 * memory to cpus and physical sockets.
1535 * On MP systems each PQ_FREE and PQ_CACHE color queue has its own spinlock
1536 * and the algorithm is adjusted to localize allocations on a per-core basis.
1537 * This is done by 'twisting' the colors.
1539 * The page is returned spinlocked and removed from its queue (it will
1540 * be on PQ_NONE), or NULL. The page is not PG_BUSY'd. The caller
1541 * is responsible for dealing with the busy-page case (usually by
1542 * deactivating the page and looping).
1544 * NOTE: This routine is carefully inlined. A non-inlined version
1545 * is available for outside callers but the only critical path is
1546 * from within this source file.
1548 * NOTE: This routine assumes that the vm_pages found in PQ_CACHE and PQ_FREE
1549 * represent stable storage, allowing us to order our locks vm_page
1550 * first, then queue.
1554 _vm_page_list_find(int basequeue, int index)
1559 m = TAILQ_FIRST(&vm_page_queues[basequeue+index].pl);
1561 m = _vm_page_list_find2(basequeue, index);
1564 vm_page_and_queue_spin_lock(m);
1565 if (m->queue == basequeue + index) {
1566 _vm_page_rem_queue_spinlocked(m);
1567 /* vm_page_t spin held, no queue spin */
1570 vm_page_and_queue_spin_unlock(m);
1576 * If we could not find the page in the desired queue try to find it in
1580 _vm_page_list_find2(int basequeue, int index)
1582 struct vpgqueues *pq;
1584 int pqmask = PQ_SET_ASSOC_MASK >> 1;
1588 index &= PQ_L2_MASK;
1589 pq = &vm_page_queues[basequeue];
1592 * Run local sets of 16, 32, 64, 128, and the whole queue if all
1593 * else fails (PQ_L2_MASK which is 255).
1596 pqmask = (pqmask << 1) | 1;
1597 for (i = 0; i <= pqmask; ++i) {
1598 pqi = (index & ~pqmask) | ((index + i) & pqmask);
1599 m = TAILQ_FIRST(&pq[pqi].pl);
1601 _vm_page_and_queue_spin_lock(m);
1602 if (m->queue == basequeue + pqi) {
1603 _vm_page_rem_queue_spinlocked(m);
1606 _vm_page_and_queue_spin_unlock(m);
1611 } while (pqmask != PQ_L2_MASK);
1617 * Returns a vm_page candidate for allocation. The page is not busied so
1618 * it can move around. The caller must busy the page (and typically
1619 * deactivate it if it cannot be busied!)
1621 * Returns a spinlocked vm_page that has been removed from its queue.
1624 vm_page_list_find(int basequeue, int index)
1626 return(_vm_page_list_find(basequeue, index));
1630 * Find a page on the cache queue with color optimization, remove it
1631 * from the queue, and busy it. The returned page will not be spinlocked.
1633 * A candidate failure will be deactivated. Candidates can fail due to
1634 * being busied by someone else, in which case they will be deactivated.
1636 * This routine may not block.
1640 vm_page_select_cache(u_short pg_color)
1645 m = _vm_page_list_find(PQ_CACHE, pg_color & PQ_L2_MASK);
1649 * (m) has been removed from its queue and spinlocked
1651 if (vm_page_busy_try(m, TRUE)) {
1652 _vm_page_deactivate_locked(m, 0);
1653 vm_page_spin_unlock(m);
1656 * We successfully busied the page
1658 if ((m->flags & (PG_UNMANAGED | PG_NEED_COMMIT)) == 0 &&
1659 m->hold_count == 0 &&
1660 m->wire_count == 0 &&
1661 (m->dirty & m->valid) == 0) {
1662 vm_page_spin_unlock(m);
1663 pagedaemon_wakeup();
1668 * The page cannot be recycled, deactivate it.
1670 _vm_page_deactivate_locked(m, 0);
1671 if (_vm_page_wakeup(m)) {
1672 vm_page_spin_unlock(m);
1675 vm_page_spin_unlock(m);
1683 * Find a free page. We attempt to inline the nominal case and fall back
1684 * to _vm_page_select_free() otherwise. A busied page is removed from
1685 * the queue and returned.
1687 * This routine may not block.
1689 static __inline vm_page_t
1690 vm_page_select_free(u_short pg_color)
1695 m = _vm_page_list_find(PQ_FREE, pg_color & PQ_L2_MASK);
1698 if (vm_page_busy_try(m, TRUE)) {
1700 * Various mechanisms such as a pmap_collect can
1701 * result in a busy page on the free queue. We
1702 * have to move the page out of the way so we can
1703 * retry the allocation. If the other thread is not
1704 * allocating the page then m->valid will remain 0 and
1705 * the pageout daemon will free the page later on.
1707 * Since we could not busy the page, however, we
1708 * cannot make assumptions as to whether the page
1709 * will be allocated by the other thread or not,
1710 * so all we can do is deactivate it to move it out
1711 * of the way. In particular, if the other thread
1712 * wires the page it may wind up on the inactive
1713 * queue and the pageout daemon will have to deal
1714 * with that case too.
1716 _vm_page_deactivate_locked(m, 0);
1717 vm_page_spin_unlock(m);
1720 * Theoretically if we are able to busy the page
1721 * atomic with the queue removal (using the vm_page
1722 * lock) nobody else should be able to mess with the
1725 KKASSERT((m->flags & (PG_UNMANAGED |
1726 PG_NEED_COMMIT)) == 0);
1727 KASSERT(m->hold_count == 0, ("m->hold_count is not zero "
1728 "pg %p q=%d flags=%08x hold=%d wire=%d",
1729 m, m->queue, m->flags, m->hold_count, m->wire_count));
1730 KKASSERT(m->wire_count == 0);
1731 vm_page_spin_unlock(m);
1732 pagedaemon_wakeup();
1734 /* return busied and removed page */
1744 * Allocate and return a memory cell associated with this VM object/offset
1745 * pair. If object is NULL an unassociated page will be allocated.
1747 * The returned page will be busied and removed from its queues. This
1748 * routine can block and may return NULL if a race occurs and the page
1749 * is found to already exist at the specified (object, pindex).
1751 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain
1752 * VM_ALLOC_QUICK like normal but cannot use cache
1753 * VM_ALLOC_SYSTEM greater free drain
1754 * VM_ALLOC_INTERRUPT allow free list to be completely drained
1755 * VM_ALLOC_ZERO advisory request for pre-zero'd page only
1756 * VM_ALLOC_FORCE_ZERO advisory request for pre-zero'd page only
1757 * VM_ALLOC_NULL_OK ok to return NULL on insertion collision
1758 * (see vm_page_grab())
1759 * VM_ALLOC_USE_GD ok to use per-gd cache
1761 * VM_ALLOC_CPU(n) allocate using specified cpu localization
1763 * The object must be held if not NULL
1764 * This routine may not block
1766 * Additional special handling is required when called from an interrupt
1767 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache
1771 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req)
1781 * Special per-cpu free VM page cache. The pages are pre-busied
1782 * and pre-zerod for us.
1784 if (gd->gd_vmpg_count && (page_req & VM_ALLOC_USE_GD)) {
1786 if (gd->gd_vmpg_count) {
1787 m = gd->gd_vmpg_array[--gd->gd_vmpg_count];
1799 * CPU localization algorithm. Break the page queues up by physical
1800 * id and core id (note that two cpu threads will have the same core
1801 * id, and core_id != gd_cpuid).
1803 * This is nowhere near perfect, for example the last pindex in a
1804 * subgroup will overflow into the next cpu or package. But this
1805 * should get us good page reuse locality in heavy mixed loads.
1807 * (may be executed before the APs are started, so other GDs might
1810 if (page_req & VM_ALLOC_CPU_SPEC)
1811 cpuid_local = VM_ALLOC_GETCPU(page_req);
1813 cpuid_local = mycpu->gd_cpuid;
1815 pg_color = vm_get_pg_color(cpuid_local, object, pindex);
1818 (VM_ALLOC_NORMAL|VM_ALLOC_QUICK|
1819 VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
1822 * Certain system threads (pageout daemon, buf_daemon's) are
1823 * allowed to eat deeper into the free page list.
1825 if (curthread->td_flags & TDF_SYSTHREAD)
1826 page_req |= VM_ALLOC_SYSTEM;
1829 * Impose various limitations. Note that the v_free_reserved test
1830 * must match the opposite of vm_page_count_target() to avoid
1831 * livelocks, be careful.
1835 if (gd->gd_vmstats.v_free_count >= gd->gd_vmstats.v_free_reserved ||
1836 ((page_req & VM_ALLOC_INTERRUPT) &&
1837 gd->gd_vmstats.v_free_count > 0) ||
1838 ((page_req & VM_ALLOC_SYSTEM) &&
1839 gd->gd_vmstats.v_cache_count == 0 &&
1840 gd->gd_vmstats.v_free_count >
1841 gd->gd_vmstats.v_interrupt_free_min)
1844 * The free queue has sufficient free pages to take one out.
1846 m = vm_page_select_free(pg_color);
1847 } else if (page_req & VM_ALLOC_NORMAL) {
1849 * Allocatable from the cache (non-interrupt only). On
1850 * success, we must free the page and try again, thus
1851 * ensuring that vmstats.v_*_free_min counters are replenished.
1854 if (curthread->td_preempted) {
1855 kprintf("vm_page_alloc(): warning, attempt to allocate"
1856 " cache page from preempting interrupt\n");
1859 m = vm_page_select_cache(pg_color);
1862 m = vm_page_select_cache(pg_color);
1865 * On success move the page into the free queue and loop.
1867 * Only do this if we can safely acquire the vm_object lock,
1868 * because this is effectively a random page and the caller
1869 * might be holding the lock shared, we don't want to
1873 KASSERT(m->dirty == 0,
1874 ("Found dirty cache page %p", m));
1875 if ((obj = m->object) != NULL) {
1876 if (vm_object_hold_try(obj)) {
1877 vm_page_protect(m, VM_PROT_NONE);
1879 /* m->object NULL here */
1880 vm_object_drop(obj);
1882 vm_page_deactivate(m);
1886 vm_page_protect(m, VM_PROT_NONE);
1893 * On failure return NULL
1895 atomic_add_int(&vm_pageout_deficit, 1);
1896 pagedaemon_wakeup();
1900 * No pages available, wakeup the pageout daemon and give up.
1902 atomic_add_int(&vm_pageout_deficit, 1);
1903 pagedaemon_wakeup();
1908 * v_free_count can race so loop if we don't find the expected
1917 * Good page found. The page has already been busied for us and
1918 * removed from its queues.
1920 KASSERT(m->dirty == 0,
1921 ("vm_page_alloc: free/cache page %p was dirty", m));
1922 KKASSERT(m->queue == PQ_NONE);
1928 * Initialize the structure, inheriting some flags but clearing
1929 * all the rest. The page has already been busied for us.
1931 vm_page_flag_clear(m, ~PG_KEEP_NEWPAGE_MASK);
1933 KKASSERT(m->wire_count == 0);
1934 KKASSERT(m->busy == 0);
1939 * Caller must be holding the object lock (asserted by
1940 * vm_page_insert()).
1942 * NOTE: Inserting a page here does not insert it into any pmaps
1943 * (which could cause us to block allocating memory).
1945 * NOTE: If no object an unassociated page is allocated, m->pindex
1946 * can be used by the caller for any purpose.
1949 if (vm_page_insert(m, object, pindex) == FALSE) {
1951 if ((page_req & VM_ALLOC_NULL_OK) == 0)
1952 panic("PAGE RACE %p[%ld]/%p",
1953 object, (long)pindex, m);
1961 * Don't wakeup too often - wakeup the pageout daemon when
1962 * we would be nearly out of memory.
1964 pagedaemon_wakeup();
1967 * A PG_BUSY page is returned.
1973 * Returns number of pages available in our DMA memory reserve
1974 * (adjusted with vm.dma_reserved=<value>m in /boot/loader.conf)
1977 vm_contig_avail_pages(void)
1982 spin_lock(&vm_contig_spin);
1983 bfree = alist_free_info(&vm_contig_alist, &blk, &count);
1984 spin_unlock(&vm_contig_spin);
1990 * Attempt to allocate contiguous physical memory with the specified
1994 vm_page_alloc_contig(vm_paddr_t low, vm_paddr_t high,
1995 unsigned long alignment, unsigned long boundary,
1996 unsigned long size, vm_memattr_t memattr)
2002 alignment >>= PAGE_SHIFT;
2005 boundary >>= PAGE_SHIFT;
2008 size = (size + PAGE_MASK) >> PAGE_SHIFT;
2010 spin_lock(&vm_contig_spin);
2011 blk = alist_alloc(&vm_contig_alist, 0, size);
2012 if (blk == ALIST_BLOCK_NONE) {
2013 spin_unlock(&vm_contig_spin);
2015 kprintf("vm_page_alloc_contig: %ldk nospace\n",
2016 (size + PAGE_MASK) * (PAGE_SIZE / 1024));
2020 if (high && ((vm_paddr_t)(blk + size) << PAGE_SHIFT) > high) {
2021 alist_free(&vm_contig_alist, blk, size);
2022 spin_unlock(&vm_contig_spin);
2024 kprintf("vm_page_alloc_contig: %ldk high "
2026 (size + PAGE_MASK) * (PAGE_SIZE / 1024),
2031 spin_unlock(&vm_contig_spin);
2032 if (vm_contig_verbose) {
2033 kprintf("vm_page_alloc_contig: %016jx/%ldk\n",
2034 (intmax_t)(vm_paddr_t)blk << PAGE_SHIFT,
2035 (size + PAGE_MASK) * (PAGE_SIZE / 1024));
2038 m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT);
2039 if (memattr != VM_MEMATTR_DEFAULT)
2040 for (i = 0;i < size;i++)
2041 pmap_page_set_memattr(&m[i], memattr);
2046 * Free contiguously allocated pages. The pages will be wired but not busy.
2047 * When freeing to the alist we leave them wired and not busy.
2050 vm_page_free_contig(vm_page_t m, unsigned long size)
2052 vm_paddr_t pa = VM_PAGE_TO_PHYS(m);
2053 vm_pindex_t start = pa >> PAGE_SHIFT;
2054 vm_pindex_t pages = (size + PAGE_MASK) >> PAGE_SHIFT;
2056 if (vm_contig_verbose) {
2057 kprintf("vm_page_free_contig: %016jx/%ldk\n",
2058 (intmax_t)pa, size / 1024);
2060 if (pa < vm_low_phys_reserved) {
2061 KKASSERT(pa + size <= vm_low_phys_reserved);
2062 spin_lock(&vm_contig_spin);
2063 alist_free(&vm_contig_alist, start, pages);
2064 spin_unlock(&vm_contig_spin);
2067 vm_page_busy_wait(m, FALSE, "cpgfr");
2068 vm_page_unwire(m, 0);
2079 * Wait for sufficient free memory for nominal heavy memory use kernel
2082 * WARNING! Be sure never to call this in any vm_pageout code path, which
2083 * will trivially deadlock the system.
2086 vm_wait_nominal(void)
2088 while (vm_page_count_min(0))
2093 * Test if vm_wait_nominal() would block.
2096 vm_test_nominal(void)
2098 if (vm_page_count_min(0))
2104 * Block until free pages are available for allocation, called in various
2105 * places before memory allocations.
2107 * The caller may loop if vm_page_count_min() == FALSE so we cannot be
2108 * more generous then that.
2114 * never wait forever
2118 lwkt_gettoken(&vm_token);
2120 if (curthread == pagethread ||
2121 curthread == emergpager) {
2123 * The pageout daemon itself needs pages, this is bad.
2125 if (vm_page_count_min(0)) {
2126 vm_pageout_pages_needed = 1;
2127 tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo);
2131 * Wakeup the pageout daemon if necessary and wait.
2133 * Do not wait indefinitely for the target to be reached,
2134 * as load might prevent it from being reached any time soon.
2135 * But wait a little to try to slow down page allocations
2136 * and to give more important threads (the pagedaemon)
2137 * allocation priority.
2139 if (vm_page_count_target()) {
2140 if (vm_pages_needed == 0) {
2141 vm_pages_needed = 1;
2142 wakeup(&vm_pages_needed);
2144 ++vm_pages_waiting; /* SMP race ok */
2145 tsleep(&vmstats.v_free_count, 0, "vmwait", timo);
2148 lwkt_reltoken(&vm_token);
2152 * Block until free pages are available for allocation
2154 * Called only from vm_fault so that processes page faulting can be
2158 vm_wait_pfault(void)
2161 * Wakeup the pageout daemon if necessary and wait.
2163 * Do not wait indefinitely for the target to be reached,
2164 * as load might prevent it from being reached any time soon.
2165 * But wait a little to try to slow down page allocations
2166 * and to give more important threads (the pagedaemon)
2167 * allocation priority.
2169 if (vm_page_count_min(0)) {
2170 lwkt_gettoken(&vm_token);
2171 while (vm_page_count_severe()) {
2172 if (vm_page_count_target()) {
2175 if (vm_pages_needed == 0) {
2176 vm_pages_needed = 1;
2177 wakeup(&vm_pages_needed);
2179 ++vm_pages_waiting; /* SMP race ok */
2180 tsleep(&vmstats.v_free_count, 0, "pfault", hz);
2183 * Do not stay stuck in the loop if the system is trying
2184 * to kill the process.
2187 if (td->td_proc && (td->td_proc->p_flags & P_LOWMEMKILL))
2191 lwkt_reltoken(&vm_token);
2196 * Put the specified page on the active list (if appropriate). Ensure
2197 * that act_count is at least ACT_INIT but do not otherwise mess with it.
2199 * The caller should be holding the page busied ? XXX
2200 * This routine may not block.
2203 vm_page_activate(vm_page_t m)
2207 vm_page_spin_lock(m);
2208 if (m->queue - m->pc != PQ_ACTIVE) {
2209 _vm_page_queue_spin_lock(m);
2210 oqueue = _vm_page_rem_queue_spinlocked(m);
2211 /* page is left spinlocked, queue is unlocked */
2213 if (oqueue == PQ_CACHE)
2214 mycpu->gd_cnt.v_reactivated++;
2215 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
2216 if (m->act_count < ACT_INIT)
2217 m->act_count = ACT_INIT;
2218 _vm_page_add_queue_spinlocked(m, PQ_ACTIVE + m->pc, 0);
2220 _vm_page_and_queue_spin_unlock(m);
2221 if (oqueue == PQ_CACHE || oqueue == PQ_FREE)
2222 pagedaemon_wakeup();
2224 if (m->act_count < ACT_INIT)
2225 m->act_count = ACT_INIT;
2226 vm_page_spin_unlock(m);
2231 * Helper routine for vm_page_free_toq() and vm_page_cache(). This
2232 * routine is called when a page has been added to the cache or free
2235 * This routine may not block.
2237 static __inline void
2238 vm_page_free_wakeup(void)
2240 globaldata_t gd = mycpu;
2243 * If the pageout daemon itself needs pages, then tell it that
2244 * there are some free.
2246 if (vm_pageout_pages_needed &&
2247 gd->gd_vmstats.v_cache_count + gd->gd_vmstats.v_free_count >=
2248 gd->gd_vmstats.v_pageout_free_min
2250 vm_pageout_pages_needed = 0;
2251 wakeup(&vm_pageout_pages_needed);
2255 * Wakeup processes that are waiting on memory.
2257 * Generally speaking we want to wakeup stuck processes as soon as
2258 * possible. !vm_page_count_min(0) is the absolute minimum point
2259 * where we can do this. Wait a bit longer to reduce degenerate
2260 * re-blocking (vm_page_free_hysteresis). The target check is just
2261 * to make sure the min-check w/hysteresis does not exceed the
2264 if (vm_pages_waiting) {
2265 if (!vm_page_count_min(vm_page_free_hysteresis) ||
2266 !vm_page_count_target()) {
2267 vm_pages_waiting = 0;
2268 wakeup(&vmstats.v_free_count);
2269 ++mycpu->gd_cnt.v_ppwakeups;
2272 if (!vm_page_count_target()) {
2274 * Plenty of pages are free, wakeup everyone.
2276 vm_pages_waiting = 0;
2277 wakeup(&vmstats.v_free_count);
2278 ++mycpu->gd_cnt.v_ppwakeups;
2279 } else if (!vm_page_count_min(0)) {
2281 * Some pages are free, wakeup someone.
2283 int wcount = vm_pages_waiting;
2286 vm_pages_waiting = wcount;
2287 wakeup_one(&vmstats.v_free_count);
2288 ++mycpu->gd_cnt.v_ppwakeups;
2295 * Returns the given page to the PQ_FREE or PQ_HOLD list and disassociates
2296 * it from its VM object.
2298 * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on
2299 * return (the page will have been freed).
2302 vm_page_free_toq(vm_page_t m)
2304 mycpu->gd_cnt.v_tfree++;
2305 KKASSERT((m->flags & PG_MAPPED) == 0);
2306 KKASSERT(m->flags & PG_BUSY);
2308 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) {
2309 kprintf("vm_page_free: pindex(%lu), busy(%d), "
2310 "PG_BUSY(%d), hold(%d)\n",
2311 (u_long)m->pindex, m->busy,
2312 ((m->flags & PG_BUSY) ? 1 : 0), m->hold_count);
2313 if ((m->queue - m->pc) == PQ_FREE)
2314 panic("vm_page_free: freeing free page");
2316 panic("vm_page_free: freeing busy page");
2320 * Remove from object, spinlock the page and its queues and
2321 * remove from any queue. No queue spinlock will be held
2322 * after this section (because the page was removed from any
2326 vm_page_and_queue_spin_lock(m);
2327 _vm_page_rem_queue_spinlocked(m);
2330 * No further management of fictitious pages occurs beyond object
2331 * and queue removal.
2333 if ((m->flags & PG_FICTITIOUS) != 0) {
2334 vm_page_spin_unlock(m);
2342 if (m->wire_count != 0) {
2343 if (m->wire_count > 1) {
2345 "vm_page_free: invalid wire count (%d), pindex: 0x%lx",
2346 m->wire_count, (long)m->pindex);
2348 panic("vm_page_free: freeing wired page");
2352 * Clear the UNMANAGED flag when freeing an unmanaged page.
2353 * Clear the NEED_COMMIT flag
2355 if (m->flags & PG_UNMANAGED)
2356 vm_page_flag_clear(m, PG_UNMANAGED);
2357 if (m->flags & PG_NEED_COMMIT)
2358 vm_page_flag_clear(m, PG_NEED_COMMIT);
2360 if (m->hold_count != 0) {
2361 _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0);
2363 _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 1);
2367 * This sequence allows us to clear PG_BUSY while still holding
2368 * its spin lock, which reduces contention vs allocators. We
2369 * must not leave the queue locked or _vm_page_wakeup() may
2372 _vm_page_queue_spin_unlock(m);
2373 if (_vm_page_wakeup(m)) {
2374 vm_page_spin_unlock(m);
2377 vm_page_spin_unlock(m);
2379 vm_page_free_wakeup();
2383 * vm_page_unmanage()
2385 * Prevent PV management from being done on the page. The page is
2386 * removed from the paging queues as if it were wired, and as a
2387 * consequence of no longer being managed the pageout daemon will not
2388 * touch it (since there is no way to locate the pte mappings for the
2389 * page). madvise() calls that mess with the pmap will also no longer
2390 * operate on the page.
2392 * Beyond that the page is still reasonably 'normal'. Freeing the page
2393 * will clear the flag.
2395 * This routine is used by OBJT_PHYS objects - objects using unswappable
2396 * physical memory as backing store rather then swap-backed memory and
2397 * will eventually be extended to support 4MB unmanaged physical
2400 * Caller must be holding the page busy.
2403 vm_page_unmanage(vm_page_t m)
2405 KKASSERT(m->flags & PG_BUSY);
2406 if ((m->flags & PG_UNMANAGED) == 0) {
2407 if (m->wire_count == 0)
2410 vm_page_flag_set(m, PG_UNMANAGED);
2414 * Mark this page as wired down by yet another map, removing it from
2415 * paging queues as necessary.
2417 * Caller must be holding the page busy.
2420 vm_page_wire(vm_page_t m)
2423 * Only bump the wire statistics if the page is not already wired,
2424 * and only unqueue the page if it is on some queue (if it is unmanaged
2425 * it is already off the queues). Don't do anything with fictitious
2426 * pages because they are always wired.
2428 KKASSERT(m->flags & PG_BUSY);
2429 if ((m->flags & PG_FICTITIOUS) == 0) {
2430 if (atomic_fetchadd_int(&m->wire_count, 1) == 0) {
2431 if ((m->flags & PG_UNMANAGED) == 0)
2433 atomic_add_int(&mycpu->gd_vmstats_adj.v_wire_count, 1);
2435 KASSERT(m->wire_count != 0,
2436 ("vm_page_wire: wire_count overflow m=%p", m));
2441 * Release one wiring of this page, potentially enabling it to be paged again.
2443 * Many pages placed on the inactive queue should actually go
2444 * into the cache, but it is difficult to figure out which. What
2445 * we do instead, if the inactive target is well met, is to put
2446 * clean pages at the head of the inactive queue instead of the tail.
2447 * This will cause them to be moved to the cache more quickly and
2448 * if not actively re-referenced, freed more quickly. If we just
2449 * stick these pages at the end of the inactive queue, heavy filesystem
2450 * meta-data accesses can cause an unnecessary paging load on memory bound
2451 * processes. This optimization causes one-time-use metadata to be
2452 * reused more quickly.
2454 * Pages marked PG_NEED_COMMIT are always activated and never placed on
2455 * the inactive queue. This helps the pageout daemon determine memory
2456 * pressure and act on out-of-memory situations more quickly.
2458 * BUT, if we are in a low-memory situation we have no choice but to
2459 * put clean pages on the cache queue.
2461 * A number of routines use vm_page_unwire() to guarantee that the page
2462 * will go into either the inactive or active queues, and will NEVER
2463 * be placed in the cache - for example, just after dirtying a page.
2464 * dirty pages in the cache are not allowed.
2466 * This routine may not block.
2469 vm_page_unwire(vm_page_t m, int activate)
2471 KKASSERT(m->flags & PG_BUSY);
2472 if (m->flags & PG_FICTITIOUS) {
2474 } else if (m->wire_count <= 0) {
2475 panic("vm_page_unwire: invalid wire count: %d", m->wire_count);
2477 if (atomic_fetchadd_int(&m->wire_count, -1) == 1) {
2478 atomic_add_int(&mycpu->gd_vmstats_adj.v_wire_count, -1);
2479 if (m->flags & PG_UNMANAGED) {
2481 } else if (activate || (m->flags & PG_NEED_COMMIT)) {
2482 vm_page_spin_lock(m);
2483 _vm_page_add_queue_spinlocked(m,
2484 PQ_ACTIVE + m->pc, 0);
2485 _vm_page_and_queue_spin_unlock(m);
2487 vm_page_spin_lock(m);
2488 vm_page_flag_clear(m, PG_WINATCFLS);
2489 _vm_page_add_queue_spinlocked(m,
2490 PQ_INACTIVE + m->pc, 0);
2491 ++vm_swapcache_inactive_heuristic;
2492 _vm_page_and_queue_spin_unlock(m);
2499 * Move the specified page to the inactive queue. If the page has
2500 * any associated swap, the swap is deallocated.
2502 * Normally athead is 0 resulting in LRU operation. athead is set
2503 * to 1 if we want this page to be 'as if it were placed in the cache',
2504 * except without unmapping it from the process address space.
2506 * vm_page's spinlock must be held on entry and will remain held on return.
2507 * This routine may not block.
2510 _vm_page_deactivate_locked(vm_page_t m, int athead)
2515 * Ignore if already inactive.
2517 if (m->queue - m->pc == PQ_INACTIVE)
2519 _vm_page_queue_spin_lock(m);
2520 oqueue = _vm_page_rem_queue_spinlocked(m);
2522 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
2523 if (oqueue == PQ_CACHE)
2524 mycpu->gd_cnt.v_reactivated++;
2525 vm_page_flag_clear(m, PG_WINATCFLS);
2526 _vm_page_add_queue_spinlocked(m, PQ_INACTIVE + m->pc, athead);
2528 ++vm_swapcache_inactive_heuristic;
2530 /* NOTE: PQ_NONE if condition not taken */
2531 _vm_page_queue_spin_unlock(m);
2532 /* leaves vm_page spinlocked */
2536 * Attempt to deactivate a page.
2541 vm_page_deactivate(vm_page_t m)
2543 vm_page_spin_lock(m);
2544 _vm_page_deactivate_locked(m, 0);
2545 vm_page_spin_unlock(m);
2549 vm_page_deactivate_locked(vm_page_t m)
2551 _vm_page_deactivate_locked(m, 0);
2555 * Attempt to move a busied page to PQ_CACHE, then unconditionally unbusy it.
2557 * This function returns non-zero if it successfully moved the page to
2560 * This function unconditionally unbusies the page on return.
2563 vm_page_try_to_cache(vm_page_t m)
2565 vm_page_spin_lock(m);
2566 if (m->dirty || m->hold_count || m->wire_count ||
2567 (m->flags & (PG_UNMANAGED | PG_NEED_COMMIT))) {
2568 if (_vm_page_wakeup(m)) {
2569 vm_page_spin_unlock(m);
2572 vm_page_spin_unlock(m);
2576 vm_page_spin_unlock(m);
2579 * Page busied by us and no longer spinlocked. Dirty pages cannot
2580 * be moved to the cache.
2582 vm_page_test_dirty(m);
2583 if (m->dirty || (m->flags & PG_NEED_COMMIT)) {
2592 * Attempt to free the page. If we cannot free it, we do nothing.
2593 * 1 is returned on success, 0 on failure.
2598 vm_page_try_to_free(vm_page_t m)
2600 vm_page_spin_lock(m);
2601 if (vm_page_busy_try(m, TRUE)) {
2602 vm_page_spin_unlock(m);
2607 * The page can be in any state, including already being on the free
2608 * queue. Check to see if it really can be freed.
2610 if (m->dirty || /* can't free if it is dirty */
2611 m->hold_count || /* or held (XXX may be wrong) */
2612 m->wire_count || /* or wired */
2613 (m->flags & (PG_UNMANAGED | /* or unmanaged */
2614 PG_NEED_COMMIT)) || /* or needs a commit */
2615 m->queue - m->pc == PQ_FREE || /* already on PQ_FREE */
2616 m->queue - m->pc == PQ_HOLD) { /* already on PQ_HOLD */
2617 if (_vm_page_wakeup(m)) {
2618 vm_page_spin_unlock(m);
2621 vm_page_spin_unlock(m);
2625 vm_page_spin_unlock(m);
2628 * We can probably free the page.
2630 * Page busied by us and no longer spinlocked. Dirty pages will
2631 * not be freed by this function. We have to re-test the
2632 * dirty bit after cleaning out the pmaps.
2634 vm_page_test_dirty(m);
2635 if (m->dirty || (m->flags & PG_NEED_COMMIT)) {
2639 vm_page_protect(m, VM_PROT_NONE);
2640 if (m->dirty || (m->flags & PG_NEED_COMMIT)) {
2651 * Put the specified page onto the page cache queue (if appropriate).
2653 * The page must be busy, and this routine will release the busy and
2654 * possibly even free the page.
2657 vm_page_cache(vm_page_t m)
2660 * Not suitable for the cache
2662 if ((m->flags & (PG_UNMANAGED | PG_NEED_COMMIT)) ||
2663 m->busy || m->wire_count || m->hold_count) {
2669 * Already in the cache (and thus not mapped)
2671 if ((m->queue - m->pc) == PQ_CACHE) {
2672 KKASSERT((m->flags & PG_MAPPED) == 0);
2678 * Caller is required to test m->dirty, but note that the act of
2679 * removing the page from its maps can cause it to become dirty
2680 * on an SMP system due to another cpu running in usermode.
2683 panic("vm_page_cache: caching a dirty page, pindex: %ld",
2688 * Remove all pmaps and indicate that the page is not
2689 * writeable or mapped. Our vm_page_protect() call may
2690 * have blocked (especially w/ VM_PROT_NONE), so recheck
2693 vm_page_protect(m, VM_PROT_NONE);
2694 if ((m->flags & (PG_UNMANAGED | PG_MAPPED)) ||
2695 m->busy || m->wire_count || m->hold_count) {
2697 } else if (m->dirty || (m->flags & PG_NEED_COMMIT)) {
2698 vm_page_deactivate(m);
2701 _vm_page_and_queue_spin_lock(m);
2702 _vm_page_rem_queue_spinlocked(m);
2703 _vm_page_add_queue_spinlocked(m, PQ_CACHE + m->pc, 0);
2704 _vm_page_queue_spin_unlock(m);
2705 if (_vm_page_wakeup(m)) {
2706 vm_page_spin_unlock(m);
2709 vm_page_spin_unlock(m);
2711 vm_page_free_wakeup();
2716 * vm_page_dontneed()
2718 * Cache, deactivate, or do nothing as appropriate. This routine
2719 * is typically used by madvise() MADV_DONTNEED.
2721 * Generally speaking we want to move the page into the cache so
2722 * it gets reused quickly. However, this can result in a silly syndrome
2723 * due to the page recycling too quickly. Small objects will not be
2724 * fully cached. On the otherhand, if we move the page to the inactive
2725 * queue we wind up with a problem whereby very large objects
2726 * unnecessarily blow away our inactive and cache queues.
2728 * The solution is to move the pages based on a fixed weighting. We
2729 * either leave them alone, deactivate them, or move them to the cache,
2730 * where moving them to the cache has the highest weighting.
2731 * By forcing some pages into other queues we eventually force the
2732 * system to balance the queues, potentially recovering other unrelated
2733 * space from active. The idea is to not force this to happen too
2736 * The page must be busied.
2739 vm_page_dontneed(vm_page_t m)
2741 static int dnweight;
2748 * occassionally leave the page alone
2750 if ((dnw & 0x01F0) == 0 ||
2751 m->queue - m->pc == PQ_INACTIVE ||
2752 m->queue - m->pc == PQ_CACHE
2754 if (m->act_count >= ACT_INIT)
2760 * If vm_page_dontneed() is inactivating a page, it must clear
2761 * the referenced flag; otherwise the pagedaemon will see references
2762 * on the page in the inactive queue and reactivate it. Until the
2763 * page can move to the cache queue, madvise's job is not done.
2765 vm_page_flag_clear(m, PG_REFERENCED);
2766 pmap_clear_reference(m);
2769 vm_page_test_dirty(m);
2771 if (m->dirty || (dnw & 0x0070) == 0) {
2773 * Deactivate the page 3 times out of 32.
2778 * Cache the page 28 times out of every 32. Note that
2779 * the page is deactivated instead of cached, but placed
2780 * at the head of the queue instead of the tail.
2784 vm_page_spin_lock(m);
2785 _vm_page_deactivate_locked(m, head);
2786 vm_page_spin_unlock(m);
2790 * These routines manipulate the 'soft busy' count for a page. A soft busy
2791 * is almost like PG_BUSY except that it allows certain compatible operations
2792 * to occur on the page while it is busy. For example, a page undergoing a
2793 * write can still be mapped read-only.
2795 * Because vm_pages can overlap buffers m->busy can be > 1. m->busy is only
2796 * adjusted while the vm_page is PG_BUSY so the flash will occur when the
2797 * busy bit is cleared.
2799 * The caller must hold the page BUSY when making these two calls.
2802 vm_page_io_start(vm_page_t m)
2804 KASSERT(m->flags & PG_BUSY, ("vm_page_io_start: page not busy!!!"));
2805 atomic_add_char(&m->busy, 1);
2806 vm_page_flag_set(m, PG_SBUSY);
2810 vm_page_io_finish(vm_page_t m)
2812 KASSERT(m->flags & PG_BUSY, ("vm_page_io_finish: page not busy!!!"));
2813 atomic_subtract_char(&m->busy, 1);
2815 vm_page_flag_clear(m, PG_SBUSY);
2819 * Indicate that a clean VM page requires a filesystem commit and cannot
2820 * be reused. Used by tmpfs.
2823 vm_page_need_commit(vm_page_t m)
2825 vm_page_flag_set(m, PG_NEED_COMMIT);
2826 vm_object_set_writeable_dirty(m->object);
2830 vm_page_clear_commit(vm_page_t m)
2832 vm_page_flag_clear(m, PG_NEED_COMMIT);
2836 * Grab a page, blocking if it is busy and allocating a page if necessary.
2837 * A busy page is returned or NULL. The page may or may not be valid and
2838 * might not be on a queue (the caller is responsible for the disposition of
2841 * If VM_ALLOC_ZERO is specified and the grab must allocate a new page, the
2842 * page will be zero'd and marked valid.
2844 * If VM_ALLOC_FORCE_ZERO is specified the page will be zero'd and marked
2845 * valid even if it already exists.
2847 * If VM_ALLOC_RETRY is specified this routine will never return NULL. Also
2848 * note that VM_ALLOC_NORMAL must be specified if VM_ALLOC_RETRY is specified.
2849 * VM_ALLOC_NULL_OK is implied when VM_ALLOC_RETRY is specified.
2851 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is
2852 * always returned if we had blocked.
2854 * This routine may not be called from an interrupt.
2856 * No other requirements.
2859 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
2865 KKASSERT(allocflags &
2866 (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
2867 vm_object_hold_shared(object);
2869 m = vm_page_lookup_busy_try(object, pindex, TRUE, &error);
2871 vm_page_sleep_busy(m, TRUE, "pgrbwt");
2872 if ((allocflags & VM_ALLOC_RETRY) == 0) {
2877 } else if (m == NULL) {
2879 vm_object_upgrade(object);
2882 if (allocflags & VM_ALLOC_RETRY)
2883 allocflags |= VM_ALLOC_NULL_OK;
2884 m = vm_page_alloc(object, pindex,
2885 allocflags & ~VM_ALLOC_RETRY);
2889 if ((allocflags & VM_ALLOC_RETRY) == 0)
2898 * If VM_ALLOC_ZERO an invalid page will be zero'd and set valid.
2900 * If VM_ALLOC_FORCE_ZERO the page is unconditionally zero'd and set
2901 * valid even if already valid.
2903 * NOTE! We have removed all of the PG_ZERO optimizations and also
2904 * removed the idle zeroing code. These optimizations actually
2905 * slow things down on modern cpus because the zerod area is
2906 * likely uncached, placing a memory-access burden on the
2907 * accesors taking the fault.
2909 * By always zeroing the page in-line with the fault, no
2910 * dynamic ram reads are needed and the caches are hot, ready
2911 * for userland to access the memory.
2913 if (m->valid == 0) {
2914 if (allocflags & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) {
2915 pmap_zero_page(VM_PAGE_TO_PHYS(m));
2916 m->valid = VM_PAGE_BITS_ALL;
2918 } else if (allocflags & VM_ALLOC_FORCE_ZERO) {
2919 pmap_zero_page(VM_PAGE_TO_PHYS(m));
2920 m->valid = VM_PAGE_BITS_ALL;
2923 vm_object_drop(object);
2928 * Mapping function for valid bits or for dirty bits in
2929 * a page. May not block.
2931 * Inputs are required to range within a page.
2937 vm_page_bits(int base, int size)
2943 base + size <= PAGE_SIZE,
2944 ("vm_page_bits: illegal base/size %d/%d", base, size)
2947 if (size == 0) /* handle degenerate case */
2950 first_bit = base >> DEV_BSHIFT;
2951 last_bit = (base + size - 1) >> DEV_BSHIFT;
2953 return ((2 << last_bit) - (1 << first_bit));
2957 * Sets portions of a page valid and clean. The arguments are expected
2958 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
2959 * of any partial chunks touched by the range. The invalid portion of
2960 * such chunks will be zero'd.
2962 * NOTE: When truncating a buffer vnode_pager_setsize() will automatically
2963 * align base to DEV_BSIZE so as not to mark clean a partially
2964 * truncated device block. Otherwise the dirty page status might be
2967 * This routine may not block.
2969 * (base + size) must be less then or equal to PAGE_SIZE.
2972 _vm_page_zero_valid(vm_page_t m, int base, int size)
2977 if (size == 0) /* handle degenerate case */
2981 * If the base is not DEV_BSIZE aligned and the valid
2982 * bit is clear, we have to zero out a portion of the
2986 if ((frag = base & ~(DEV_BSIZE - 1)) != base &&
2987 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0
2989 pmap_zero_page_area(
2997 * If the ending offset is not DEV_BSIZE aligned and the
2998 * valid bit is clear, we have to zero out a portion of
3002 endoff = base + size;
3004 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff &&
3005 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0
3007 pmap_zero_page_area(
3010 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))
3016 * Set valid, clear dirty bits. If validating the entire
3017 * page we can safely clear the pmap modify bit. We also
3018 * use this opportunity to clear the PG_NOSYNC flag. If a process
3019 * takes a write fault on a MAP_NOSYNC memory area the flag will
3022 * We set valid bits inclusive of any overlap, but we can only
3023 * clear dirty bits for DEV_BSIZE chunks that are fully within
3026 * Page must be busied?
3027 * No other requirements.
3030 vm_page_set_valid(vm_page_t m, int base, int size)
3032 _vm_page_zero_valid(m, base, size);
3033 m->valid |= vm_page_bits(base, size);
3038 * Set valid bits and clear dirty bits.
3040 * Page must be busied by caller.
3042 * NOTE: This function does not clear the pmap modified bit.
3043 * Also note that e.g. NFS may use a byte-granular base
3046 * No other requirements.
3049 vm_page_set_validclean(vm_page_t m, int base, int size)
3053 _vm_page_zero_valid(m, base, size);
3054 pagebits = vm_page_bits(base, size);
3055 m->valid |= pagebits;
3056 m->dirty &= ~pagebits;
3057 if (base == 0 && size == PAGE_SIZE) {
3058 /*pmap_clear_modify(m);*/
3059 vm_page_flag_clear(m, PG_NOSYNC);
3064 * Set valid & dirty. Used by buwrite()
3066 * Page must be busied by caller.
3069 vm_page_set_validdirty(vm_page_t m, int base, int size)
3073 pagebits = vm_page_bits(base, size);
3074 m->valid |= pagebits;
3075 m->dirty |= pagebits;
3077 vm_object_set_writeable_dirty(m->object);
3083 * NOTE: This function does not clear the pmap modified bit.
3084 * Also note that e.g. NFS may use a byte-granular base
3087 * Page must be busied?
3088 * No other requirements.
3091 vm_page_clear_dirty(vm_page_t m, int base, int size)
3093 m->dirty &= ~vm_page_bits(base, size);
3094 if (base == 0 && size == PAGE_SIZE) {
3095 /*pmap_clear_modify(m);*/
3096 vm_page_flag_clear(m, PG_NOSYNC);
3101 * Make the page all-dirty.
3103 * Also make sure the related object and vnode reflect the fact that the
3104 * object may now contain a dirty page.
3106 * Page must be busied?
3107 * No other requirements.
3110 vm_page_dirty(vm_page_t m)
3113 int pqtype = m->queue - m->pc;
3115 KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE,
3116 ("vm_page_dirty: page in free/cache queue!"));
3117 if (m->dirty != VM_PAGE_BITS_ALL) {
3118 m->dirty = VM_PAGE_BITS_ALL;
3120 vm_object_set_writeable_dirty(m->object);
3125 * Invalidates DEV_BSIZE'd chunks within a page. Both the
3126 * valid and dirty bits for the effected areas are cleared.
3128 * Page must be busied?
3130 * No other requirements.
3133 vm_page_set_invalid(vm_page_t m, int base, int size)
3137 bits = vm_page_bits(base, size);
3140 atomic_add_int(&m->object->generation, 1);
3144 * The kernel assumes that the invalid portions of a page contain
3145 * garbage, but such pages can be mapped into memory by user code.
3146 * When this occurs, we must zero out the non-valid portions of the
3147 * page so user code sees what it expects.
3149 * Pages are most often semi-valid when the end of a file is mapped
3150 * into memory and the file's size is not page aligned.
3152 * Page must be busied?
3153 * No other requirements.
3156 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
3162 * Scan the valid bits looking for invalid sections that
3163 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the
3164 * valid bit may be set ) have already been zerod by
3165 * vm_page_set_validclean().
3167 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
3168 if (i == (PAGE_SIZE / DEV_BSIZE) ||
3169 (m->valid & (1 << i))
3172 pmap_zero_page_area(
3175 (i - b) << DEV_BSHIFT
3183 * setvalid is TRUE when we can safely set the zero'd areas
3184 * as being valid. We can do this if there are no cache consistency
3185 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS.
3188 m->valid = VM_PAGE_BITS_ALL;
3192 * Is a (partial) page valid? Note that the case where size == 0
3193 * will return FALSE in the degenerate case where the page is entirely
3194 * invalid, and TRUE otherwise.
3197 * No other requirements.
3200 vm_page_is_valid(vm_page_t m, int base, int size)
3202 int bits = vm_page_bits(base, size);
3204 if (m->valid && ((m->valid & bits) == bits))
3211 * update dirty bits from pmap/mmu. May not block.
3213 * Caller must hold the page busy
3216 vm_page_test_dirty(vm_page_t m)
3218 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) {
3223 #include "opt_ddb.h"
3225 #include <ddb/ddb.h>
3227 DB_SHOW_COMMAND(page, vm_page_print_page_info)
3229 db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count);
3230 db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count);
3231 db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count);
3232 db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count);
3233 db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count);
3234 db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved);
3235 db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min);
3236 db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target);
3237 db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min);
3238 db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target);
3241 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
3244 db_printf("PQ_FREE:");
3245 for (i = 0; i < PQ_L2_SIZE; i++) {
3246 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt);
3250 db_printf("PQ_CACHE:");
3251 for(i = 0; i < PQ_L2_SIZE; i++) {
3252 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt);
3256 db_printf("PQ_ACTIVE:");
3257 for(i = 0; i < PQ_L2_SIZE; i++) {
3258 db_printf(" %d", vm_page_queues[PQ_ACTIVE + i].lcnt);
3262 db_printf("PQ_INACTIVE:");
3263 for(i = 0; i < PQ_L2_SIZE; i++) {
3264 db_printf(" %d", vm_page_queues[PQ_INACTIVE + i].lcnt);