4 * Copyright (c) 1991 Regents of the University of California.
7 * This code is derived from software contributed to Berkeley by
8 * The Mach Operating System project at Carnegie-Mellon University.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91
35 * $FreeBSD: src/sys/vm/vm_page.c,v 1.147.2.18 2002/03/10 05:03:19 alc Exp $
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
44 * Permission to use, copy, modify and distribute this software and
45 * its documentation is hereby granted, provided that both the copyright
46 * notice and this permission notice appear in all copies of the
47 * software, derivative works or modified versions, and any portions
48 * thereof, and that both notices appear in supporting documentation.
50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
54 * Carnegie Mellon requests users of this software to return to
56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
57 * School of Computer Science
58 * Carnegie Mellon University
59 * Pittsburgh PA 15213-3890
61 * any improvements or extensions that they make and grant Carnegie the
62 * rights to redistribute these changes.
65 * Resident memory management module. The module manipulates 'VM pages'.
66 * A VM page is the core building block for memory management.
69 #include <sys/param.h>
70 #include <sys/systm.h>
71 #include <sys/malloc.h>
73 #include <sys/vmmeter.h>
74 #include <sys/vnode.h>
75 #include <sys/kernel.h>
76 #include <sys/alist.h>
77 #include <sys/sysctl.h>
78 #include <sys/cpu_topology.h>
81 #include <vm/vm_param.h>
83 #include <vm/vm_kern.h>
85 #include <vm/vm_map.h>
86 #include <vm/vm_object.h>
87 #include <vm/vm_page.h>
88 #include <vm/vm_pageout.h>
89 #include <vm/vm_pager.h>
90 #include <vm/vm_extern.h>
91 #include <vm/swap_pager.h>
93 #include <machine/inttypes.h>
94 #include <machine/md_var.h>
95 #include <machine/specialreg.h>
97 #include <vm/vm_page2.h>
98 #include <sys/spinlock2.h>
101 * Action hash for user umtx support.
103 #define VMACTION_HSIZE 256
104 #define VMACTION_HMASK (VMACTION_HSIZE - 1)
107 * SET - Minimum required set associative size, must be a power of 2. We
108 * want this to match or exceed the set-associativeness of the cpu.
110 * GRP - A larger set that allows bleed-over into the domains of other
111 * nearby cpus. Also must be a power of 2. Used by the page zeroing
112 * code to smooth things out a bit.
114 #define PQ_SET_ASSOC 16
115 #define PQ_SET_ASSOC_MASK (PQ_SET_ASSOC - 1)
117 #define PQ_GRP_ASSOC (PQ_SET_ASSOC * 2)
118 #define PQ_GRP_ASSOC_MASK (PQ_GRP_ASSOC - 1)
120 static void vm_page_queue_init(void);
121 static void vm_page_free_wakeup(void);
122 static vm_page_t
vm_page_select_cache(u_short pg_color
);
123 static vm_page_t
_vm_page_list_find2(int basequeue
, int index
);
124 static void _vm_page_deactivate_locked(vm_page_t m
, int athead
);
127 * Array of tailq lists
129 __cachealign
struct vpgqueues vm_page_queues
[PQ_COUNT
];
131 LIST_HEAD(vm_page_action_list
, vm_page_action
);
132 struct vm_page_action_list action_list
[VMACTION_HSIZE
];
133 static volatile int vm_pages_waiting
;
135 static struct alist vm_contig_alist
;
136 static struct almeta vm_contig_ameta
[ALIST_RECORDS_65536
];
137 static struct spinlock vm_contig_spin
= SPINLOCK_INITIALIZER(&vm_contig_spin
, "vm_contig_spin");
139 static u_long vm_dma_reserved
= 0;
140 TUNABLE_ULONG("vm.dma_reserved", &vm_dma_reserved
);
141 SYSCTL_ULONG(_vm
, OID_AUTO
, dma_reserved
, CTLFLAG_RD
, &vm_dma_reserved
, 0,
142 "Memory reserved for DMA");
143 SYSCTL_UINT(_vm
, OID_AUTO
, dma_free_pages
, CTLFLAG_RD
,
144 &vm_contig_alist
.bl_free
, 0, "Memory reserved for DMA");
146 static int vm_contig_verbose
= 0;
147 TUNABLE_INT("vm.contig_verbose", &vm_contig_verbose
);
149 RB_GENERATE2(vm_page_rb_tree
, vm_page
, rb_entry
, rb_vm_page_compare
,
150 vm_pindex_t
, pindex
);
153 vm_page_queue_init(void)
157 for (i
= 0; i
< PQ_L2_SIZE
; i
++)
158 vm_page_queues
[PQ_FREE
+i
].cnt
= &vmstats
.v_free_count
;
159 for (i
= 0; i
< PQ_L2_SIZE
; i
++)
160 vm_page_queues
[PQ_CACHE
+i
].cnt
= &vmstats
.v_cache_count
;
161 for (i
= 0; i
< PQ_L2_SIZE
; i
++)
162 vm_page_queues
[PQ_INACTIVE
+i
].cnt
= &vmstats
.v_inactive_count
;
163 for (i
= 0; i
< PQ_L2_SIZE
; i
++)
164 vm_page_queues
[PQ_ACTIVE
+i
].cnt
= &vmstats
.v_active_count
;
165 for (i
= 0; i
< PQ_L2_SIZE
; i
++)
166 vm_page_queues
[PQ_HOLD
+i
].cnt
= &vmstats
.v_active_count
;
167 /* PQ_NONE has no queue */
169 for (i
= 0; i
< PQ_COUNT
; i
++) {
170 TAILQ_INIT(&vm_page_queues
[i
].pl
);
171 spin_init(&vm_page_queues
[i
].spin
, "vm_page_queue_init");
174 for (i
= 0; i
< VMACTION_HSIZE
; i
++)
175 LIST_INIT(&action_list
[i
]);
179 * note: place in initialized data section? Is this necessary?
182 int vm_page_array_size
= 0;
183 vm_page_t vm_page_array
= NULL
;
184 vm_paddr_t vm_low_phys_reserved
;
189 * Sets the page size, perhaps based upon the memory size.
190 * Must be called before any use of page-size dependent functions.
193 vm_set_page_size(void)
195 if (vmstats
.v_page_size
== 0)
196 vmstats
.v_page_size
= PAGE_SIZE
;
197 if (((vmstats
.v_page_size
- 1) & vmstats
.v_page_size
) != 0)
198 panic("vm_set_page_size: page size not a power of two");
204 * Add a new page to the freelist for use by the system. New pages
205 * are added to both the head and tail of the associated free page
206 * queue in a bottom-up fashion, so both zero'd and non-zero'd page
207 * requests pull 'recent' adds (higher physical addresses) first.
209 * Beware that the page zeroing daemon will also be running soon after
210 * boot, moving pages from the head to the tail of the PQ_FREE queues.
212 * Must be called in a critical section.
215 vm_add_new_page(vm_paddr_t pa
)
217 struct vpgqueues
*vpq
;
220 m
= PHYS_TO_VM_PAGE(pa
);
223 m
->pc
= (pa
>> PAGE_SHIFT
) & PQ_L2_MASK
;
224 m
->pat_mode
= PAT_WRITE_BACK
;
226 * Twist for cpu localization in addition to page coloring, so
227 * different cpus selecting by m->queue get different page colors.
229 m
->pc
^= ((pa
>> PAGE_SHIFT
) / PQ_L2_SIZE
) & PQ_L2_MASK
;
230 m
->pc
^= ((pa
>> PAGE_SHIFT
) / (PQ_L2_SIZE
* PQ_L2_SIZE
)) & PQ_L2_MASK
;
232 * Reserve a certain number of contiguous low memory pages for
233 * contigmalloc() to use.
235 if (pa
< vm_low_phys_reserved
) {
236 atomic_add_int(&vmstats
.v_page_count
, 1);
237 atomic_add_int(&vmstats
.v_dma_pages
, 1);
240 atomic_add_int(&vmstats
.v_wire_count
, 1);
241 alist_free(&vm_contig_alist
, pa
>> PAGE_SHIFT
, 1);
248 m
->queue
= m
->pc
+ PQ_FREE
;
249 KKASSERT(m
->dirty
== 0);
251 atomic_add_int(&vmstats
.v_page_count
, 1);
252 atomic_add_int(&vmstats
.v_free_count
, 1);
253 vpq
= &vm_page_queues
[m
->queue
];
254 TAILQ_INSERT_HEAD(&vpq
->pl
, m
, pageq
);
261 * Initializes the resident memory module.
263 * Preallocates memory for critical VM structures and arrays prior to
264 * kernel_map becoming available.
266 * Memory is allocated from (virtual2_start, virtual2_end) if available,
267 * otherwise memory is allocated from (virtual_start, virtual_end).
269 * On x86-64 (virtual_start, virtual_end) is only 2GB and may not be
270 * large enough to hold vm_page_array & other structures for machines with
271 * large amounts of ram, so we want to use virtual2* when available.
274 vm_page_startup(void)
276 vm_offset_t vaddr
= virtual2_start
? virtual2_start
: virtual_start
;
279 vm_paddr_t page_range
;
286 vm_paddr_t biggestone
, biggestsize
;
293 vaddr
= round_page(vaddr
);
295 for (i
= 0; phys_avail
[i
+ 1]; i
+= 2) {
296 phys_avail
[i
] = round_page64(phys_avail
[i
]);
297 phys_avail
[i
+ 1] = trunc_page64(phys_avail
[i
+ 1]);
300 for (i
= 0; phys_avail
[i
+ 1]; i
+= 2) {
301 vm_paddr_t size
= phys_avail
[i
+ 1] - phys_avail
[i
];
303 if (size
> biggestsize
) {
311 end
= phys_avail
[biggestone
+1];
312 end
= trunc_page(end
);
315 * Initialize the queue headers for the free queue, the active queue
316 * and the inactive queue.
318 vm_page_queue_init();
320 #if !defined(_KERNEL_VIRTUAL)
322 * VKERNELs don't support minidumps and as such don't need
325 * Allocate a bitmap to indicate that a random physical page
326 * needs to be included in a minidump.
328 * The amd64 port needs this to indicate which direct map pages
329 * need to be dumped, via calls to dump_add_page()/dump_drop_page().
331 * However, i386 still needs this workspace internally within the
332 * minidump code. In theory, they are not needed on i386, but are
333 * included should the sf_buf code decide to use them.
335 page_range
= phys_avail
[(nblocks
- 1) * 2 + 1] / PAGE_SIZE
;
336 vm_page_dump_size
= round_page(roundup2(page_range
, NBBY
) / NBBY
);
337 end
-= vm_page_dump_size
;
338 vm_page_dump
= (void *)pmap_map(&vaddr
, end
, end
+ vm_page_dump_size
,
339 VM_PROT_READ
| VM_PROT_WRITE
);
340 bzero((void *)vm_page_dump
, vm_page_dump_size
);
343 * Compute the number of pages of memory that will be available for
344 * use (taking into account the overhead of a page structure per
347 first_page
= phys_avail
[0] / PAGE_SIZE
;
348 page_range
= phys_avail
[(nblocks
- 1) * 2 + 1] / PAGE_SIZE
- first_page
;
349 npages
= (total
- (page_range
* sizeof(struct vm_page
))) / PAGE_SIZE
;
351 #ifndef _KERNEL_VIRTUAL
353 * (only applies to real kernels)
355 * Reserve a large amount of low memory for potential 32-bit DMA
356 * space allocations. Once device initialization is complete we
357 * release most of it, but keep (vm_dma_reserved) memory reserved
358 * for later use. Typically for X / graphics. Through trial and
359 * error we find that GPUs usually requires ~60-100MB or so.
361 * By default, 128M is left in reserve on machines with 2G+ of ram.
363 vm_low_phys_reserved
= (vm_paddr_t
)65536 << PAGE_SHIFT
;
364 if (vm_low_phys_reserved
> total
/ 4)
365 vm_low_phys_reserved
= total
/ 4;
366 if (vm_dma_reserved
== 0) {
367 vm_dma_reserved
= 128 * 1024 * 1024; /* 128MB */
368 if (vm_dma_reserved
> total
/ 16)
369 vm_dma_reserved
= total
/ 16;
372 alist_init(&vm_contig_alist
, 65536, vm_contig_ameta
,
373 ALIST_RECORDS_65536
);
376 * Initialize the mem entry structures now, and put them in the free
379 new_end
= trunc_page(end
- page_range
* sizeof(struct vm_page
));
380 mapped
= pmap_map(&vaddr
, new_end
, end
, VM_PROT_READ
| VM_PROT_WRITE
);
381 vm_page_array
= (vm_page_t
)mapped
;
383 #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL)
385 * since pmap_map on amd64 returns stuff out of a direct-map region,
386 * we have to manually add these pages to the minidump tracking so
387 * that they can be dumped, including the vm_page_array.
389 for (pa
= new_end
; pa
< phys_avail
[biggestone
+ 1]; pa
+= PAGE_SIZE
)
394 * Clear all of the page structures
396 bzero((caddr_t
) vm_page_array
, page_range
* sizeof(struct vm_page
));
397 vm_page_array_size
= page_range
;
400 * Construct the free queue(s) in ascending order (by physical
401 * address) so that the first 16MB of physical memory is allocated
402 * last rather than first. On large-memory machines, this avoids
403 * the exhaustion of low physical memory before isa_dmainit has run.
405 vmstats
.v_page_count
= 0;
406 vmstats
.v_free_count
= 0;
407 for (i
= 0; phys_avail
[i
+ 1] && npages
> 0; i
+= 2) {
412 last_pa
= phys_avail
[i
+ 1];
413 while (pa
< last_pa
&& npages
-- > 0) {
419 virtual2_start
= vaddr
;
421 virtual_start
= vaddr
;
425 * We tended to reserve a ton of memory for contigmalloc(). Now that most
426 * drivers have initialized we want to return most the remaining free
427 * reserve back to the VM page queues so they can be used for normal
430 * We leave vm_dma_reserved bytes worth of free pages in the reserve pool.
433 vm_page_startup_finish(void *dummy __unused
)
442 spin_lock(&vm_contig_spin
);
444 bfree
= alist_free_info(&vm_contig_alist
, &blk
, &count
);
445 if (bfree
<= vm_dma_reserved
/ PAGE_SIZE
)
451 * Figure out how much of the initial reserve we have to
452 * free in order to reach our target.
454 bfree
-= vm_dma_reserved
/ PAGE_SIZE
;
456 blk
+= count
- bfree
;
461 * Calculate the nearest power of 2 <= count.
463 for (xcount
= 1; xcount
<= count
; xcount
<<= 1)
466 blk
+= count
- xcount
;
470 * Allocate the pages from the alist, then free them to
471 * the normal VM page queues.
473 * Pages allocated from the alist are wired. We have to
474 * busy, unwire, and free them. We must also adjust
475 * vm_low_phys_reserved before freeing any pages to prevent
478 rblk
= alist_alloc(&vm_contig_alist
, blk
, count
);
480 kprintf("vm_page_startup_finish: Unable to return "
481 "dma space @0x%08x/%d -> 0x%08x\n",
485 atomic_add_int(&vmstats
.v_dma_pages
, -count
);
486 spin_unlock(&vm_contig_spin
);
488 m
= PHYS_TO_VM_PAGE((vm_paddr_t
)blk
<< PAGE_SHIFT
);
489 vm_low_phys_reserved
= VM_PAGE_TO_PHYS(m
);
491 vm_page_busy_wait(m
, FALSE
, "cpgfr");
492 vm_page_unwire(m
, 0);
497 spin_lock(&vm_contig_spin
);
499 spin_unlock(&vm_contig_spin
);
502 * Print out how much DMA space drivers have already allocated and
503 * how much is left over.
505 kprintf("DMA space used: %jdk, remaining available: %jdk\n",
506 (intmax_t)(vmstats
.v_dma_pages
- vm_contig_alist
.bl_free
) *
508 (intmax_t)vm_contig_alist
.bl_free
* (PAGE_SIZE
/ 1024));
510 SYSINIT(vm_pgend
, SI_SUB_PROC0_POST
, SI_ORDER_ANY
,
511 vm_page_startup_finish
, NULL
);
515 * Scan comparison function for Red-Black tree scans. An inclusive
516 * (start,end) is expected. Other fields are not used.
519 rb_vm_page_scancmp(struct vm_page
*p
, void *data
)
521 struct rb_vm_page_scan_info
*info
= data
;
523 if (p
->pindex
< info
->start_pindex
)
525 if (p
->pindex
> info
->end_pindex
)
531 rb_vm_page_compare(struct vm_page
*p1
, struct vm_page
*p2
)
533 if (p1
->pindex
< p2
->pindex
)
535 if (p1
->pindex
> p2
->pindex
)
541 vm_page_init(vm_page_t m
)
543 /* do nothing for now. Called from pmap_page_init() */
547 * Each page queue has its own spin lock, which is fairly optimal for
548 * allocating and freeing pages at least.
550 * The caller must hold the vm_page_spin_lock() before locking a vm_page's
551 * queue spinlock via this function. Also note that m->queue cannot change
552 * unless both the page and queue are locked.
556 _vm_page_queue_spin_lock(vm_page_t m
)
561 if (queue
!= PQ_NONE
) {
562 spin_lock(&vm_page_queues
[queue
].spin
);
563 KKASSERT(queue
== m
->queue
);
569 _vm_page_queue_spin_unlock(vm_page_t m
)
575 if (queue
!= PQ_NONE
)
576 spin_unlock(&vm_page_queues
[queue
].spin
);
581 _vm_page_queues_spin_lock(u_short queue
)
584 if (queue
!= PQ_NONE
)
585 spin_lock(&vm_page_queues
[queue
].spin
);
591 _vm_page_queues_spin_unlock(u_short queue
)
594 if (queue
!= PQ_NONE
)
595 spin_unlock(&vm_page_queues
[queue
].spin
);
599 vm_page_queue_spin_lock(vm_page_t m
)
601 _vm_page_queue_spin_lock(m
);
605 vm_page_queues_spin_lock(u_short queue
)
607 _vm_page_queues_spin_lock(queue
);
611 vm_page_queue_spin_unlock(vm_page_t m
)
613 _vm_page_queue_spin_unlock(m
);
617 vm_page_queues_spin_unlock(u_short queue
)
619 _vm_page_queues_spin_unlock(queue
);
623 * This locks the specified vm_page and its queue in the proper order
624 * (page first, then queue). The queue may change so the caller must
629 _vm_page_and_queue_spin_lock(vm_page_t m
)
631 vm_page_spin_lock(m
);
632 _vm_page_queue_spin_lock(m
);
637 _vm_page_and_queue_spin_unlock(vm_page_t m
)
639 _vm_page_queues_spin_unlock(m
->queue
);
640 vm_page_spin_unlock(m
);
644 vm_page_and_queue_spin_unlock(vm_page_t m
)
646 _vm_page_and_queue_spin_unlock(m
);
650 vm_page_and_queue_spin_lock(vm_page_t m
)
652 _vm_page_and_queue_spin_lock(m
);
656 * Helper function removes vm_page from its current queue.
657 * Returns the base queue the page used to be on.
659 * The vm_page and the queue must be spinlocked.
660 * This function will unlock the queue but leave the page spinlocked.
662 static __inline u_short
663 _vm_page_rem_queue_spinlocked(vm_page_t m
)
665 struct vpgqueues
*pq
;
670 if (queue
!= PQ_NONE
) {
671 pq
= &vm_page_queues
[queue
];
672 TAILQ_REMOVE(&pq
->pl
, m
, pageq
);
673 atomic_add_int(pq
->cnt
, -1);
677 if ((queue
- m
->pc
) == PQ_CACHE
|| (queue
- m
->pc
) == PQ_FREE
)
679 vm_page_queues_spin_unlock(oqueue
); /* intended */
685 * Helper function places the vm_page on the specified queue.
687 * The vm_page must be spinlocked.
688 * This function will return with both the page and the queue locked.
691 _vm_page_add_queue_spinlocked(vm_page_t m
, u_short queue
, int athead
)
693 struct vpgqueues
*pq
;
695 KKASSERT(m
->queue
== PQ_NONE
);
697 if (queue
!= PQ_NONE
) {
698 vm_page_queues_spin_lock(queue
);
699 pq
= &vm_page_queues
[queue
];
701 atomic_add_int(pq
->cnt
, 1);
705 * PQ_FREE is always handled LIFO style to try to provide
706 * cache-hot pages to programs.
708 if (queue
- m
->pc
== PQ_FREE
) {
709 TAILQ_INSERT_HEAD(&pq
->pl
, m
, pageq
);
711 TAILQ_INSERT_HEAD(&pq
->pl
, m
, pageq
);
713 TAILQ_INSERT_TAIL(&pq
->pl
, m
, pageq
);
715 /* leave the queue spinlocked */
720 * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE)
721 * m->busy is zero. Returns TRUE if it had to sleep, FALSE if we
722 * did not. Only one sleep call will be made before returning.
724 * This function does NOT busy the page and on return the page is not
725 * guaranteed to be available.
728 vm_page_sleep_busy(vm_page_t m
, int also_m_busy
, const char *msg
)
736 if ((flags
& PG_BUSY
) == 0 &&
737 (also_m_busy
== 0 || (flags
& PG_SBUSY
) == 0)) {
740 tsleep_interlock(m
, 0);
741 if (atomic_cmpset_int(&m
->flags
, flags
,
742 flags
| PG_WANTED
| PG_REFERENCED
)) {
743 tsleep(m
, PINTERLOCKED
, msg
, 0);
750 * This calculates and returns a page color given an optional VM object and
751 * either a pindex or an iterator. We attempt to return a cpu-localized
752 * pg_color that is still roughly 16-way set-associative. The CPU topology
753 * is used if it was probed.
755 * The caller may use the returned value to index into e.g. PQ_FREE when
756 * allocating a page in order to nominally obtain pages that are hopefully
757 * already localized to the requesting cpu. This function is not able to
758 * provide any sort of guarantee of this, but does its best to improve
759 * hardware cache management performance.
761 * WARNING! The caller must mask the returned value with PQ_L2_MASK.
764 vm_get_pg_color(globaldata_t gd
, vm_object_t object
, vm_pindex_t pindex
)
771 phys_id
= get_cpu_phys_id(gd
->gd_cpuid
);
772 core_id
= get_cpu_core_id(gd
->gd_cpuid
);
773 object_pg_color
= object
? object
->pg_color
: 0;
775 if (cpu_topology_phys_ids
&& cpu_topology_core_ids
) {
776 int grpsize
= PQ_L2_SIZE
/ cpu_topology_phys_ids
;
778 if (grpsize
/ cpu_topology_core_ids
>= PQ_SET_ASSOC
) {
780 * Enough space for a full break-down.
782 pg_color
= phys_id
* grpsize
;
783 pg_color
+= core_id
* grpsize
/ cpu_topology_core_ids
;
784 pg_color
+= (pindex
+ object_pg_color
) %
785 (grpsize
/ cpu_topology_core_ids
);
788 * Not enough space, split up by physical package,
789 * then split up by core id but only down to a
790 * 16-set. If all else fails, force a 16-set.
792 pg_color
= phys_id
* grpsize
;
794 pg_color
+= 16 * (core_id
% (grpsize
/ 16));
799 pg_color
+= (pindex
+ object_pg_color
) %
804 * Unknown topology, distribute things evenly.
806 pg_color
= gd
->gd_cpuid
* PQ_L2_SIZE
/ ncpus
;
807 pg_color
+= pindex
+ object_pg_color
;
813 * Wait until PG_BUSY can be set, then set it. If also_m_busy is TRUE we
814 * also wait for m->busy to become 0 before setting PG_BUSY.
817 VM_PAGE_DEBUG_EXT(vm_page_busy_wait
)(vm_page_t m
,
818 int also_m_busy
, const char *msg
826 if (flags
& PG_BUSY
) {
827 tsleep_interlock(m
, 0);
828 if (atomic_cmpset_int(&m
->flags
, flags
,
829 flags
| PG_WANTED
| PG_REFERENCED
)) {
830 tsleep(m
, PINTERLOCKED
, msg
, 0);
832 } else if (also_m_busy
&& (flags
& PG_SBUSY
)) {
833 tsleep_interlock(m
, 0);
834 if (atomic_cmpset_int(&m
->flags
, flags
,
835 flags
| PG_WANTED
| PG_REFERENCED
)) {
836 tsleep(m
, PINTERLOCKED
, msg
, 0);
839 if (atomic_cmpset_int(&m
->flags
, flags
,
843 m
->busy_line
= lineno
;
852 * Attempt to set PG_BUSY. If also_m_busy is TRUE we only succeed if m->busy
855 * Returns non-zero on failure.
858 VM_PAGE_DEBUG_EXT(vm_page_busy_try
)(vm_page_t m
, int also_m_busy
868 if (also_m_busy
&& (flags
& PG_SBUSY
))
870 if (atomic_cmpset_int(&m
->flags
, flags
, flags
| PG_BUSY
)) {
873 m
->busy_line
= lineno
;
881 * Clear the PG_BUSY flag and return non-zero to indicate to the caller
882 * that a wakeup() should be performed.
884 * The vm_page must be spinlocked and will remain spinlocked on return.
885 * The related queue must NOT be spinlocked (which could deadlock us).
891 _vm_page_wakeup(vm_page_t m
)
898 if (atomic_cmpset_int(&m
->flags
, flags
,
899 flags
& ~(PG_BUSY
| PG_WANTED
))) {
903 return(flags
& PG_WANTED
);
907 * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This
908 * is typically the last call you make on a page before moving onto
912 vm_page_wakeup(vm_page_t m
)
914 KASSERT(m
->flags
& PG_BUSY
, ("vm_page_wakeup: page not busy!!!"));
915 vm_page_spin_lock(m
);
916 if (_vm_page_wakeup(m
)) {
917 vm_page_spin_unlock(m
);
920 vm_page_spin_unlock(m
);
925 * Holding a page keeps it from being reused. Other parts of the system
926 * can still disassociate the page from its current object and free it, or
927 * perform read or write I/O on it and/or otherwise manipulate the page,
928 * but if the page is held the VM system will leave the page and its data
929 * intact and not reuse the page for other purposes until the last hold
930 * reference is released. (see vm_page_wire() if you want to prevent the
931 * page from being disassociated from its object too).
933 * The caller must still validate the contents of the page and, if necessary,
934 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete
935 * before manipulating the page.
937 * XXX get vm_page_spin_lock() here and move FREE->HOLD if necessary
940 vm_page_hold(vm_page_t m
)
942 vm_page_spin_lock(m
);
943 atomic_add_int(&m
->hold_count
, 1);
944 if (m
->queue
- m
->pc
== PQ_FREE
) {
945 _vm_page_queue_spin_lock(m
);
946 _vm_page_rem_queue_spinlocked(m
);
947 _vm_page_add_queue_spinlocked(m
, PQ_HOLD
+ m
->pc
, 0);
948 _vm_page_queue_spin_unlock(m
);
950 vm_page_spin_unlock(m
);
954 * The opposite of vm_page_hold(). If the page is on the HOLD queue
955 * it was freed while held and must be moved back to the FREE queue.
958 vm_page_unhold(vm_page_t m
)
960 KASSERT(m
->hold_count
> 0 && m
->queue
- m
->pc
!= PQ_FREE
,
961 ("vm_page_unhold: pg %p illegal hold_count (%d) or on FREE queue (%d)",
962 m
, m
->hold_count
, m
->queue
- m
->pc
));
963 vm_page_spin_lock(m
);
964 atomic_add_int(&m
->hold_count
, -1);
965 if (m
->hold_count
== 0 && m
->queue
- m
->pc
== PQ_HOLD
) {
966 _vm_page_queue_spin_lock(m
);
967 _vm_page_rem_queue_spinlocked(m
);
968 _vm_page_add_queue_spinlocked(m
, PQ_FREE
+ m
->pc
, 0);
969 _vm_page_queue_spin_unlock(m
);
971 vm_page_spin_unlock(m
);
977 * Create a fictitious page with the specified physical address and
978 * memory attribute. The memory attribute is the only the machine-
979 * dependent aspect of a fictitious page that must be initialized.
983 vm_page_initfake(vm_page_t m
, vm_paddr_t paddr
, vm_memattr_t memattr
)
986 if ((m
->flags
& PG_FICTITIOUS
) != 0) {
988 * The page's memattr might have changed since the
989 * previous initialization. Update the pmap to the
994 m
->phys_addr
= paddr
;
996 /* Fictitious pages don't use "segind". */
997 /* Fictitious pages don't use "order" or "pool". */
998 m
->flags
= PG_FICTITIOUS
| PG_UNMANAGED
| PG_BUSY
;
1002 pmap_page_set_memattr(m
, memattr
);
1006 * Inserts the given vm_page into the object and object list.
1008 * The pagetables are not updated but will presumably fault the page
1009 * in if necessary, or if a kernel page the caller will at some point
1010 * enter the page into the kernel's pmap. We are not allowed to block
1011 * here so we *can't* do this anyway.
1013 * This routine may not block.
1014 * This routine must be called with the vm_object held.
1015 * This routine must be called with a critical section held.
1017 * This routine returns TRUE if the page was inserted into the object
1018 * successfully, and FALSE if the page already exists in the object.
1021 vm_page_insert(vm_page_t m
, vm_object_t object
, vm_pindex_t pindex
)
1023 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(object
));
1024 if (m
->object
!= NULL
)
1025 panic("vm_page_insert: already inserted");
1027 object
->generation
++;
1030 * Record the object/offset pair in this page and add the
1031 * pv_list_count of the page to the object.
1033 * The vm_page spin lock is required for interactions with the pmap.
1035 vm_page_spin_lock(m
);
1038 if (vm_page_rb_tree_RB_INSERT(&object
->rb_memq
, m
)) {
1041 vm_page_spin_unlock(m
);
1044 ++object
->resident_page_count
;
1045 ++mycpu
->gd_vmtotal
.t_rm
;
1046 /* atomic_add_int(&object->agg_pv_list_count, m->md.pv_list_count); */
1047 vm_page_spin_unlock(m
);
1050 * Since we are inserting a new and possibly dirty page,
1051 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags.
1053 if ((m
->valid
& m
->dirty
) ||
1054 (m
->flags
& (PG_WRITEABLE
| PG_NEED_COMMIT
)))
1055 vm_object_set_writeable_dirty(object
);
1058 * Checks for a swap assignment and sets PG_SWAPPED if appropriate.
1060 swap_pager_page_inserted(m
);
1065 * Removes the given vm_page_t from the (object,index) table
1067 * The underlying pmap entry (if any) is NOT removed here.
1068 * This routine may not block.
1070 * The page must be BUSY and will remain BUSY on return.
1071 * No other requirements.
1073 * NOTE: FreeBSD side effect was to unbusy the page on return. We leave
1077 vm_page_remove(vm_page_t m
)
1081 if (m
->object
== NULL
) {
1085 if ((m
->flags
& PG_BUSY
) == 0)
1086 panic("vm_page_remove: page not busy");
1090 vm_object_hold(object
);
1093 * Remove the page from the object and update the object.
1095 * The vm_page spin lock is required for interactions with the pmap.
1097 vm_page_spin_lock(m
);
1098 vm_page_rb_tree_RB_REMOVE(&object
->rb_memq
, m
);
1099 --object
->resident_page_count
;
1100 --mycpu
->gd_vmtotal
.t_rm
;
1101 /* atomic_add_int(&object->agg_pv_list_count, -m->md.pv_list_count); */
1103 vm_page_spin_unlock(m
);
1105 object
->generation
++;
1107 vm_object_drop(object
);
1111 * Locate and return the page at (object, pindex), or NULL if the
1112 * page could not be found.
1114 * The caller must hold the vm_object token.
1117 vm_page_lookup(vm_object_t object
, vm_pindex_t pindex
)
1122 * Search the hash table for this object/offset pair
1124 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object
));
1125 m
= vm_page_rb_tree_RB_LOOKUP(&object
->rb_memq
, pindex
);
1126 KKASSERT(m
== NULL
|| (m
->object
== object
&& m
->pindex
== pindex
));
1131 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait
)(struct vm_object
*object
,
1133 int also_m_busy
, const char *msg
1139 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object
));
1140 m
= vm_page_rb_tree_RB_LOOKUP(&object
->rb_memq
, pindex
);
1142 KKASSERT(m
->object
== object
&& m
->pindex
== pindex
);
1145 if (flags
& PG_BUSY
) {
1146 tsleep_interlock(m
, 0);
1147 if (atomic_cmpset_int(&m
->flags
, flags
,
1148 flags
| PG_WANTED
| PG_REFERENCED
)) {
1149 tsleep(m
, PINTERLOCKED
, msg
, 0);
1150 m
= vm_page_rb_tree_RB_LOOKUP(&object
->rb_memq
,
1153 } else if (also_m_busy
&& (flags
& PG_SBUSY
)) {
1154 tsleep_interlock(m
, 0);
1155 if (atomic_cmpset_int(&m
->flags
, flags
,
1156 flags
| PG_WANTED
| PG_REFERENCED
)) {
1157 tsleep(m
, PINTERLOCKED
, msg
, 0);
1158 m
= vm_page_rb_tree_RB_LOOKUP(&object
->rb_memq
,
1161 } else if (atomic_cmpset_int(&m
->flags
, flags
,
1163 #ifdef VM_PAGE_DEBUG
1164 m
->busy_func
= func
;
1165 m
->busy_line
= lineno
;
1174 * Attempt to lookup and busy a page.
1176 * Returns NULL if the page could not be found
1178 * Returns a vm_page and error == TRUE if the page exists but could not
1181 * Returns a vm_page and error == FALSE on success.
1184 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try
)(struct vm_object
*object
,
1186 int also_m_busy
, int *errorp
1192 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object
));
1193 m
= vm_page_rb_tree_RB_LOOKUP(&object
->rb_memq
, pindex
);
1196 KKASSERT(m
->object
== object
&& m
->pindex
== pindex
);
1199 if (flags
& PG_BUSY
) {
1203 if (also_m_busy
&& (flags
& PG_SBUSY
)) {
1207 if (atomic_cmpset_int(&m
->flags
, flags
, flags
| PG_BUSY
)) {
1208 #ifdef VM_PAGE_DEBUG
1209 m
->busy_func
= func
;
1210 m
->busy_line
= lineno
;
1219 * Attempt to repurpose the passed-in page. If the passed-in page cannot
1220 * be repurposed it will be released, *must_reenter will be set to 1, and
1221 * this function will fall-through to vm_page_lookup_busy_try().
1223 * The passed-in page must be wired and not busy. The returned page will
1224 * be busied and not wired.
1226 * A different page may be returned. The returned page will be busied and
1229 * NULL can be returned. If so, the required page could not be busied.
1230 * The passed-in page will be unwired.
1233 vm_page_repurpose(struct vm_object
*object
, vm_pindex_t pindex
,
1234 int also_m_busy
, int *errorp
, vm_page_t m
,
1235 int *must_reenter
, int *iswired
)
1238 vm_page_busy_wait(m
, TRUE
, "biodep");
1239 if ((m
->flags
& (PG_UNMANAGED
| PG_MAPPED
| PG_FICTITIOUS
)) ||
1240 m
->busy
|| m
->wire_count
!= 1 || m
->hold_count
) {
1241 vm_page_unwire(m
, 0);
1243 /* fall through to normal lookup */
1244 } else if (m
->dirty
|| (m
->flags
& PG_NEED_COMMIT
)) {
1245 vm_page_unwire(m
, 0);
1246 vm_page_deactivate(m
);
1248 /* fall through to normal lookup */
1251 * We can safely repurpose the page. It should
1252 * already be unqueued.
1254 KKASSERT(m
->queue
== PQ_NONE
&& m
->dirty
== 0);
1258 if (vm_page_insert(m
, object
, pindex
)) {
1264 vm_page_unwire(m
, 0);
1266 /* fall through to normal lookup */
1271 m
= vm_page_lookup_busy_try(object
, pindex
, also_m_busy
, errorp
);
1277 * Caller must hold the related vm_object
1280 vm_page_next(vm_page_t m
)
1284 next
= vm_page_rb_tree_RB_NEXT(m
);
1285 if (next
&& next
->pindex
!= m
->pindex
+ 1)
1293 * Move the given vm_page from its current object to the specified
1294 * target object/offset. The page must be busy and will remain so
1297 * new_object must be held.
1298 * This routine might block. XXX ?
1300 * NOTE: Swap associated with the page must be invalidated by the move. We
1301 * have to do this for several reasons: (1) we aren't freeing the
1302 * page, (2) we are dirtying the page, (3) the VM system is probably
1303 * moving the page from object A to B, and will then later move
1304 * the backing store from A to B and we can't have a conflict.
1306 * NOTE: We *always* dirty the page. It is necessary both for the
1307 * fact that we moved it, and because we may be invalidating
1308 * swap. If the page is on the cache, we have to deactivate it
1309 * or vm_page_dirty() will panic. Dirty pages are not allowed
1313 vm_page_rename(vm_page_t m
, vm_object_t new_object
, vm_pindex_t new_pindex
)
1315 KKASSERT(m
->flags
& PG_BUSY
);
1316 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(new_object
));
1318 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(m
->object
));
1321 if (vm_page_insert(m
, new_object
, new_pindex
) == FALSE
) {
1322 panic("vm_page_rename: target exists (%p,%"PRIu64
")",
1323 new_object
, new_pindex
);
1325 if (m
->queue
- m
->pc
== PQ_CACHE
)
1326 vm_page_deactivate(m
);
1331 * vm_page_unqueue() without any wakeup. This routine is used when a page
1332 * is to remain BUSYied by the caller.
1334 * This routine may not block.
1337 vm_page_unqueue_nowakeup(vm_page_t m
)
1339 vm_page_and_queue_spin_lock(m
);
1340 (void)_vm_page_rem_queue_spinlocked(m
);
1341 vm_page_spin_unlock(m
);
1345 * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon
1348 * This routine may not block.
1351 vm_page_unqueue(vm_page_t m
)
1355 vm_page_and_queue_spin_lock(m
);
1356 queue
= _vm_page_rem_queue_spinlocked(m
);
1357 if (queue
== PQ_FREE
|| queue
== PQ_CACHE
) {
1358 vm_page_spin_unlock(m
);
1359 pagedaemon_wakeup();
1361 vm_page_spin_unlock(m
);
1366 * vm_page_list_find()
1368 * Find a page on the specified queue with color optimization.
1370 * The page coloring optimization attempts to locate a page that does
1371 * not overload other nearby pages in the object in the cpu's L1 or L2
1372 * caches. We need this optimization because cpu caches tend to be
1373 * physical caches, while object spaces tend to be virtual.
1375 * The page coloring optimization also, very importantly, tries to localize
1376 * memory to cpus and physical sockets.
1378 * On MP systems each PQ_FREE and PQ_CACHE color queue has its own spinlock
1379 * and the algorithm is adjusted to localize allocations on a per-core basis.
1380 * This is done by 'twisting' the colors.
1382 * The page is returned spinlocked and removed from its queue (it will
1383 * be on PQ_NONE), or NULL. The page is not PG_BUSY'd. The caller
1384 * is responsible for dealing with the busy-page case (usually by
1385 * deactivating the page and looping).
1387 * NOTE: This routine is carefully inlined. A non-inlined version
1388 * is available for outside callers but the only critical path is
1389 * from within this source file.
1391 * NOTE: This routine assumes that the vm_pages found in PQ_CACHE and PQ_FREE
1392 * represent stable storage, allowing us to order our locks vm_page
1393 * first, then queue.
1397 _vm_page_list_find(int basequeue
, int index
, boolean_t prefer_zero
)
1403 m
= TAILQ_LAST(&vm_page_queues
[basequeue
+index
].pl
,
1406 m
= TAILQ_FIRST(&vm_page_queues
[basequeue
+index
].pl
);
1409 m
= _vm_page_list_find2(basequeue
, index
);
1412 vm_page_and_queue_spin_lock(m
);
1413 if (m
->queue
== basequeue
+ index
) {
1414 _vm_page_rem_queue_spinlocked(m
);
1415 /* vm_page_t spin held, no queue spin */
1418 vm_page_and_queue_spin_unlock(m
);
1424 * If we could not find the page in the desired queue try to find it in
1428 _vm_page_list_find2(int basequeue
, int index
)
1430 struct vpgqueues
*pq
;
1432 int pqmask
= PQ_SET_ASSOC_MASK
>> 1;
1436 index
&= PQ_L2_MASK
;
1437 pq
= &vm_page_queues
[basequeue
];
1440 * Run local sets of 16, 32, 64, 128, and the whole queue if all
1441 * else fails (PQ_L2_MASK which is 255).
1444 pqmask
= (pqmask
<< 1) | 1;
1445 for (i
= 0; i
<= pqmask
; ++i
) {
1446 pqi
= (index
& ~pqmask
) | ((index
+ i
) & pqmask
);
1447 m
= TAILQ_FIRST(&pq
[pqi
].pl
);
1449 _vm_page_and_queue_spin_lock(m
);
1450 if (m
->queue
== basequeue
+ pqi
) {
1451 _vm_page_rem_queue_spinlocked(m
);
1454 _vm_page_and_queue_spin_unlock(m
);
1459 } while (pqmask
!= PQ_L2_MASK
);
1465 * Returns a vm_page candidate for allocation. The page is not busied so
1466 * it can move around. The caller must busy the page (and typically
1467 * deactivate it if it cannot be busied!)
1469 * Returns a spinlocked vm_page that has been removed from its queue.
1472 vm_page_list_find(int basequeue
, int index
, boolean_t prefer_zero
)
1474 return(_vm_page_list_find(basequeue
, index
, prefer_zero
));
1478 * Find a page on the cache queue with color optimization, remove it
1479 * from the queue, and busy it. The returned page will not be spinlocked.
1481 * A candidate failure will be deactivated. Candidates can fail due to
1482 * being busied by someone else, in which case they will be deactivated.
1484 * This routine may not block.
1488 vm_page_select_cache(u_short pg_color
)
1493 m
= _vm_page_list_find(PQ_CACHE
, pg_color
& PQ_L2_MASK
, FALSE
);
1497 * (m) has been removed from its queue and spinlocked
1499 if (vm_page_busy_try(m
, TRUE
)) {
1500 _vm_page_deactivate_locked(m
, 0);
1501 vm_page_spin_unlock(m
);
1504 * We successfully busied the page
1506 if ((m
->flags
& (PG_UNMANAGED
| PG_NEED_COMMIT
)) == 0 &&
1507 m
->hold_count
== 0 &&
1508 m
->wire_count
== 0 &&
1509 (m
->dirty
& m
->valid
) == 0) {
1510 vm_page_spin_unlock(m
);
1511 pagedaemon_wakeup();
1516 * The page cannot be recycled, deactivate it.
1518 _vm_page_deactivate_locked(m
, 0);
1519 if (_vm_page_wakeup(m
)) {
1520 vm_page_spin_unlock(m
);
1523 vm_page_spin_unlock(m
);
1531 * Find a free or zero page, with specified preference. We attempt to
1532 * inline the nominal case and fall back to _vm_page_select_free()
1533 * otherwise. A busied page is removed from the queue and returned.
1535 * This routine may not block.
1537 static __inline vm_page_t
1538 vm_page_select_free(u_short pg_color
, boolean_t prefer_zero
)
1543 m
= _vm_page_list_find(PQ_FREE
, pg_color
& PQ_L2_MASK
,
1547 if (vm_page_busy_try(m
, TRUE
)) {
1549 * Various mechanisms such as a pmap_collect can
1550 * result in a busy page on the free queue. We
1551 * have to move the page out of the way so we can
1552 * retry the allocation. If the other thread is not
1553 * allocating the page then m->valid will remain 0 and
1554 * the pageout daemon will free the page later on.
1556 * Since we could not busy the page, however, we
1557 * cannot make assumptions as to whether the page
1558 * will be allocated by the other thread or not,
1559 * so all we can do is deactivate it to move it out
1560 * of the way. In particular, if the other thread
1561 * wires the page it may wind up on the inactive
1562 * queue and the pageout daemon will have to deal
1563 * with that case too.
1565 _vm_page_deactivate_locked(m
, 0);
1566 vm_page_spin_unlock(m
);
1569 * Theoretically if we are able to busy the page
1570 * atomic with the queue removal (using the vm_page
1571 * lock) nobody else should be able to mess with the
1574 KKASSERT((m
->flags
& (PG_UNMANAGED
|
1575 PG_NEED_COMMIT
)) == 0);
1576 KASSERT(m
->hold_count
== 0, ("m->hold_count is not zero "
1577 "pg %p q=%d flags=%08x hold=%d wire=%d",
1578 m
, m
->queue
, m
->flags
, m
->hold_count
, m
->wire_count
));
1579 KKASSERT(m
->wire_count
== 0);
1580 vm_page_spin_unlock(m
);
1581 pagedaemon_wakeup();
1583 /* return busied and removed page */
1593 * Allocate and return a memory cell associated with this VM object/offset
1594 * pair. If object is NULL an unassociated page will be allocated.
1596 * The returned page will be busied and removed from its queues. This
1597 * routine can block and may return NULL if a race occurs and the page
1598 * is found to already exist at the specified (object, pindex).
1600 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain
1601 * VM_ALLOC_QUICK like normal but cannot use cache
1602 * VM_ALLOC_SYSTEM greater free drain
1603 * VM_ALLOC_INTERRUPT allow free list to be completely drained
1604 * VM_ALLOC_ZERO advisory request for pre-zero'd page only
1605 * VM_ALLOC_FORCE_ZERO advisory request for pre-zero'd page only
1606 * VM_ALLOC_NULL_OK ok to return NULL on insertion collision
1607 * (see vm_page_grab())
1608 * VM_ALLOC_USE_GD ok to use per-gd cache
1610 * The object must be held if not NULL
1611 * This routine may not block
1613 * Additional special handling is required when called from an interrupt
1614 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache
1618 vm_page_alloc(vm_object_t object
, vm_pindex_t pindex
, int page_req
)
1620 globaldata_t gd
= mycpu
;
1627 * Special per-cpu free VM page cache. The pages are pre-busied
1628 * and pre-zerod for us.
1630 if (gd
->gd_vmpg_count
&& (page_req
& VM_ALLOC_USE_GD
)) {
1632 if (gd
->gd_vmpg_count
) {
1633 m
= gd
->gd_vmpg_array
[--gd
->gd_vmpg_count
];
1645 * CPU localization algorithm. Break the page queues up by physical
1646 * id and core id (note that two cpu threads will have the same core
1647 * id, and core_id != gd_cpuid).
1649 * This is nowhere near perfect, for example the last pindex in a
1650 * subgroup will overflow into the next cpu or package. But this
1651 * should get us good page reuse locality in heavy mixed loads.
1653 pg_color
= vm_get_pg_color(gd
, object
, pindex
);
1656 (VM_ALLOC_NORMAL
|VM_ALLOC_QUICK
|
1657 VM_ALLOC_INTERRUPT
|VM_ALLOC_SYSTEM
));
1660 * Certain system threads (pageout daemon, buf_daemon's) are
1661 * allowed to eat deeper into the free page list.
1663 if (curthread
->td_flags
& TDF_SYSTHREAD
)
1664 page_req
|= VM_ALLOC_SYSTEM
;
1667 * Impose various limitations. Note that the v_free_reserved test
1668 * must match the opposite of vm_page_count_target() to avoid
1669 * livelocks, be careful.
1672 if (vmstats
.v_free_count
>= vmstats
.v_free_reserved
||
1673 ((page_req
& VM_ALLOC_INTERRUPT
) && vmstats
.v_free_count
> 0) ||
1674 ((page_req
& VM_ALLOC_SYSTEM
) && vmstats
.v_cache_count
== 0 &&
1675 vmstats
.v_free_count
> vmstats
.v_interrupt_free_min
)
1678 * The free queue has sufficient free pages to take one out.
1680 if (page_req
& (VM_ALLOC_ZERO
| VM_ALLOC_FORCE_ZERO
))
1681 m
= vm_page_select_free(pg_color
, TRUE
);
1683 m
= vm_page_select_free(pg_color
, FALSE
);
1684 } else if (page_req
& VM_ALLOC_NORMAL
) {
1686 * Allocatable from the cache (non-interrupt only). On
1687 * success, we must free the page and try again, thus
1688 * ensuring that vmstats.v_*_free_min counters are replenished.
1691 if (curthread
->td_preempted
) {
1692 kprintf("vm_page_alloc(): warning, attempt to allocate"
1693 " cache page from preempting interrupt\n");
1696 m
= vm_page_select_cache(pg_color
);
1699 m
= vm_page_select_cache(pg_color
);
1702 * On success move the page into the free queue and loop.
1704 * Only do this if we can safely acquire the vm_object lock,
1705 * because this is effectively a random page and the caller
1706 * might be holding the lock shared, we don't want to
1710 KASSERT(m
->dirty
== 0,
1711 ("Found dirty cache page %p", m
));
1712 if ((obj
= m
->object
) != NULL
) {
1713 if (vm_object_hold_try(obj
)) {
1714 vm_page_protect(m
, VM_PROT_NONE
);
1716 /* m->object NULL here */
1717 vm_object_drop(obj
);
1719 vm_page_deactivate(m
);
1723 vm_page_protect(m
, VM_PROT_NONE
);
1730 * On failure return NULL
1732 #if defined(DIAGNOSTIC)
1733 if (vmstats
.v_cache_count
> 0)
1734 kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats
.v_cache_count
);
1736 vm_pageout_deficit
++;
1737 pagedaemon_wakeup();
1741 * No pages available, wakeup the pageout daemon and give up.
1743 vm_pageout_deficit
++;
1744 pagedaemon_wakeup();
1749 * v_free_count can race so loop if we don't find the expected
1756 * Good page found. The page has already been busied for us and
1757 * removed from its queues.
1759 KASSERT(m
->dirty
== 0,
1760 ("vm_page_alloc: free/cache page %p was dirty", m
));
1761 KKASSERT(m
->queue
== PQ_NONE
);
1767 * Initialize the structure, inheriting some flags but clearing
1768 * all the rest. The page has already been busied for us.
1770 vm_page_flag_clear(m
, ~(PG_BUSY
| PG_SBUSY
));
1771 KKASSERT(m
->wire_count
== 0);
1772 KKASSERT(m
->busy
== 0);
1777 * Caller must be holding the object lock (asserted by
1778 * vm_page_insert()).
1780 * NOTE: Inserting a page here does not insert it into any pmaps
1781 * (which could cause us to block allocating memory).
1783 * NOTE: If no object an unassociated page is allocated, m->pindex
1784 * can be used by the caller for any purpose.
1787 if (vm_page_insert(m
, object
, pindex
) == FALSE
) {
1789 if ((page_req
& VM_ALLOC_NULL_OK
) == 0)
1790 panic("PAGE RACE %p[%ld]/%p",
1791 object
, (long)pindex
, m
);
1799 * Don't wakeup too often - wakeup the pageout daemon when
1800 * we would be nearly out of memory.
1802 pagedaemon_wakeup();
1805 * A PG_BUSY page is returned.
1811 * Returns number of pages available in our DMA memory reserve
1812 * (adjusted with vm.dma_reserved=<value>m in /boot/loader.conf)
1815 vm_contig_avail_pages(void)
1820 spin_lock(&vm_contig_spin
);
1821 bfree
= alist_free_info(&vm_contig_alist
, &blk
, &count
);
1822 spin_unlock(&vm_contig_spin
);
1828 * Attempt to allocate contiguous physical memory with the specified
1832 vm_page_alloc_contig(vm_paddr_t low
, vm_paddr_t high
,
1833 unsigned long alignment
, unsigned long boundary
,
1834 unsigned long size
, vm_memattr_t memattr
)
1840 alignment
>>= PAGE_SHIFT
;
1843 boundary
>>= PAGE_SHIFT
;
1846 size
= (size
+ PAGE_MASK
) >> PAGE_SHIFT
;
1848 spin_lock(&vm_contig_spin
);
1849 blk
= alist_alloc(&vm_contig_alist
, 0, size
);
1850 if (blk
== ALIST_BLOCK_NONE
) {
1851 spin_unlock(&vm_contig_spin
);
1853 kprintf("vm_page_alloc_contig: %ldk nospace\n",
1854 (size
+ PAGE_MASK
) * (PAGE_SIZE
/ 1024));
1858 if (high
&& ((vm_paddr_t
)(blk
+ size
) << PAGE_SHIFT
) > high
) {
1859 alist_free(&vm_contig_alist
, blk
, size
);
1860 spin_unlock(&vm_contig_spin
);
1862 kprintf("vm_page_alloc_contig: %ldk high "
1864 (size
+ PAGE_MASK
) * (PAGE_SIZE
/ 1024),
1869 spin_unlock(&vm_contig_spin
);
1870 if (vm_contig_verbose
) {
1871 kprintf("vm_page_alloc_contig: %016jx/%ldk\n",
1872 (intmax_t)(vm_paddr_t
)blk
<< PAGE_SHIFT
,
1873 (size
+ PAGE_MASK
) * (PAGE_SIZE
/ 1024));
1876 m
= PHYS_TO_VM_PAGE((vm_paddr_t
)blk
<< PAGE_SHIFT
);
1877 if (memattr
!= VM_MEMATTR_DEFAULT
)
1878 for (i
= 0;i
< size
;i
++)
1879 pmap_page_set_memattr(&m
[i
], memattr
);
1884 * Free contiguously allocated pages. The pages will be wired but not busy.
1885 * When freeing to the alist we leave them wired and not busy.
1888 vm_page_free_contig(vm_page_t m
, unsigned long size
)
1890 vm_paddr_t pa
= VM_PAGE_TO_PHYS(m
);
1891 vm_pindex_t start
= pa
>> PAGE_SHIFT
;
1892 vm_pindex_t pages
= (size
+ PAGE_MASK
) >> PAGE_SHIFT
;
1894 if (vm_contig_verbose
) {
1895 kprintf("vm_page_free_contig: %016jx/%ldk\n",
1896 (intmax_t)pa
, size
/ 1024);
1898 if (pa
< vm_low_phys_reserved
) {
1899 KKASSERT(pa
+ size
<= vm_low_phys_reserved
);
1900 spin_lock(&vm_contig_spin
);
1901 alist_free(&vm_contig_alist
, start
, pages
);
1902 spin_unlock(&vm_contig_spin
);
1905 vm_page_busy_wait(m
, FALSE
, "cpgfr");
1906 vm_page_unwire(m
, 0);
1917 * Wait for sufficient free memory for nominal heavy memory use kernel
1920 * WARNING! Be sure never to call this in any vm_pageout code path, which
1921 * will trivially deadlock the system.
1924 vm_wait_nominal(void)
1926 while (vm_page_count_min(0))
1931 * Test if vm_wait_nominal() would block.
1934 vm_test_nominal(void)
1936 if (vm_page_count_min(0))
1942 * Block until free pages are available for allocation, called in various
1943 * places before memory allocations.
1945 * The caller may loop if vm_page_count_min() == FALSE so we cannot be
1946 * more generous then that.
1952 * never wait forever
1956 lwkt_gettoken(&vm_token
);
1958 if (curthread
== pagethread
) {
1960 * The pageout daemon itself needs pages, this is bad.
1962 if (vm_page_count_min(0)) {
1963 vm_pageout_pages_needed
= 1;
1964 tsleep(&vm_pageout_pages_needed
, 0, "VMWait", timo
);
1968 * Wakeup the pageout daemon if necessary and wait.
1970 * Do not wait indefinitely for the target to be reached,
1971 * as load might prevent it from being reached any time soon.
1972 * But wait a little to try to slow down page allocations
1973 * and to give more important threads (the pagedaemon)
1974 * allocation priority.
1976 if (vm_page_count_target()) {
1977 if (vm_pages_needed
== 0) {
1978 vm_pages_needed
= 1;
1979 wakeup(&vm_pages_needed
);
1981 ++vm_pages_waiting
; /* SMP race ok */
1982 tsleep(&vmstats
.v_free_count
, 0, "vmwait", timo
);
1985 lwkt_reltoken(&vm_token
);
1989 * Block until free pages are available for allocation
1991 * Called only from vm_fault so that processes page faulting can be
1995 vm_wait_pfault(void)
1998 * Wakeup the pageout daemon if necessary and wait.
2000 * Do not wait indefinitely for the target to be reached,
2001 * as load might prevent it from being reached any time soon.
2002 * But wait a little to try to slow down page allocations
2003 * and to give more important threads (the pagedaemon)
2004 * allocation priority.
2006 if (vm_page_count_min(0)) {
2007 lwkt_gettoken(&vm_token
);
2008 while (vm_page_count_severe()) {
2009 if (vm_page_count_target()) {
2010 if (vm_pages_needed
== 0) {
2011 vm_pages_needed
= 1;
2012 wakeup(&vm_pages_needed
);
2014 ++vm_pages_waiting
; /* SMP race ok */
2015 tsleep(&vmstats
.v_free_count
, 0, "pfault", hz
);
2018 lwkt_reltoken(&vm_token
);
2023 * Put the specified page on the active list (if appropriate). Ensure
2024 * that act_count is at least ACT_INIT but do not otherwise mess with it.
2026 * The caller should be holding the page busied ? XXX
2027 * This routine may not block.
2030 vm_page_activate(vm_page_t m
)
2034 vm_page_spin_lock(m
);
2035 if (m
->queue
- m
->pc
!= PQ_ACTIVE
) {
2036 _vm_page_queue_spin_lock(m
);
2037 oqueue
= _vm_page_rem_queue_spinlocked(m
);
2038 /* page is left spinlocked, queue is unlocked */
2040 if (oqueue
== PQ_CACHE
)
2041 mycpu
->gd_cnt
.v_reactivated
++;
2042 if (m
->wire_count
== 0 && (m
->flags
& PG_UNMANAGED
) == 0) {
2043 if (m
->act_count
< ACT_INIT
)
2044 m
->act_count
= ACT_INIT
;
2045 _vm_page_add_queue_spinlocked(m
, PQ_ACTIVE
+ m
->pc
, 0);
2047 _vm_page_and_queue_spin_unlock(m
);
2048 if (oqueue
== PQ_CACHE
|| oqueue
== PQ_FREE
)
2049 pagedaemon_wakeup();
2051 if (m
->act_count
< ACT_INIT
)
2052 m
->act_count
= ACT_INIT
;
2053 vm_page_spin_unlock(m
);
2058 * Helper routine for vm_page_free_toq() and vm_page_cache(). This
2059 * routine is called when a page has been added to the cache or free
2062 * This routine may not block.
2064 static __inline
void
2065 vm_page_free_wakeup(void)
2068 * If the pageout daemon itself needs pages, then tell it that
2069 * there are some free.
2071 if (vm_pageout_pages_needed
&&
2072 vmstats
.v_cache_count
+ vmstats
.v_free_count
>=
2073 vmstats
.v_pageout_free_min
2075 vm_pageout_pages_needed
= 0;
2076 wakeup(&vm_pageout_pages_needed
);
2080 * Wakeup processes that are waiting on memory.
2082 * Generally speaking we want to wakeup stuck processes as soon as
2083 * possible. !vm_page_count_min(0) is the absolute minimum point
2084 * where we can do this. Wait a bit longer to reduce degenerate
2085 * re-blocking (vm_page_free_hysteresis). The target check is just
2086 * to make sure the min-check w/hysteresis does not exceed the
2089 if (vm_pages_waiting
) {
2090 if (!vm_page_count_min(vm_page_free_hysteresis
) ||
2091 !vm_page_count_target()) {
2092 vm_pages_waiting
= 0;
2093 wakeup(&vmstats
.v_free_count
);
2094 ++mycpu
->gd_cnt
.v_ppwakeups
;
2097 if (!vm_page_count_target()) {
2099 * Plenty of pages are free, wakeup everyone.
2101 vm_pages_waiting
= 0;
2102 wakeup(&vmstats
.v_free_count
);
2103 ++mycpu
->gd_cnt
.v_ppwakeups
;
2104 } else if (!vm_page_count_min(0)) {
2106 * Some pages are free, wakeup someone.
2108 int wcount
= vm_pages_waiting
;
2111 vm_pages_waiting
= wcount
;
2112 wakeup_one(&vmstats
.v_free_count
);
2113 ++mycpu
->gd_cnt
.v_ppwakeups
;
2120 * Returns the given page to the PQ_FREE or PQ_HOLD list and disassociates
2121 * it from its VM object.
2123 * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on
2124 * return (the page will have been freed).
2127 vm_page_free_toq(vm_page_t m
)
2129 mycpu
->gd_cnt
.v_tfree
++;
2130 KKASSERT((m
->flags
& PG_MAPPED
) == 0);
2131 KKASSERT(m
->flags
& PG_BUSY
);
2133 if (m
->busy
|| ((m
->queue
- m
->pc
) == PQ_FREE
)) {
2134 kprintf("vm_page_free: pindex(%lu), busy(%d), "
2135 "PG_BUSY(%d), hold(%d)\n",
2136 (u_long
)m
->pindex
, m
->busy
,
2137 ((m
->flags
& PG_BUSY
) ? 1 : 0), m
->hold_count
);
2138 if ((m
->queue
- m
->pc
) == PQ_FREE
)
2139 panic("vm_page_free: freeing free page");
2141 panic("vm_page_free: freeing busy page");
2145 * Remove from object, spinlock the page and its queues and
2146 * remove from any queue. No queue spinlock will be held
2147 * after this section (because the page was removed from any
2151 vm_page_and_queue_spin_lock(m
);
2152 _vm_page_rem_queue_spinlocked(m
);
2155 * No further management of fictitious pages occurs beyond object
2156 * and queue removal.
2158 if ((m
->flags
& PG_FICTITIOUS
) != 0) {
2159 vm_page_spin_unlock(m
);
2167 if (m
->wire_count
!= 0) {
2168 if (m
->wire_count
> 1) {
2170 "vm_page_free: invalid wire count (%d), pindex: 0x%lx",
2171 m
->wire_count
, (long)m
->pindex
);
2173 panic("vm_page_free: freeing wired page");
2177 * Clear the UNMANAGED flag when freeing an unmanaged page.
2178 * Clear the NEED_COMMIT flag
2180 if (m
->flags
& PG_UNMANAGED
)
2181 vm_page_flag_clear(m
, PG_UNMANAGED
);
2182 if (m
->flags
& PG_NEED_COMMIT
)
2183 vm_page_flag_clear(m
, PG_NEED_COMMIT
);
2185 if (m
->hold_count
!= 0) {
2186 _vm_page_add_queue_spinlocked(m
, PQ_HOLD
+ m
->pc
, 0);
2188 _vm_page_add_queue_spinlocked(m
, PQ_FREE
+ m
->pc
, 0);
2192 * This sequence allows us to clear PG_BUSY while still holding
2193 * its spin lock, which reduces contention vs allocators. We
2194 * must not leave the queue locked or _vm_page_wakeup() may
2197 _vm_page_queue_spin_unlock(m
);
2198 if (_vm_page_wakeup(m
)) {
2199 vm_page_spin_unlock(m
);
2202 vm_page_spin_unlock(m
);
2204 vm_page_free_wakeup();
2208 * vm_page_unmanage()
2210 * Prevent PV management from being done on the page. The page is
2211 * removed from the paging queues as if it were wired, and as a
2212 * consequence of no longer being managed the pageout daemon will not
2213 * touch it (since there is no way to locate the pte mappings for the
2214 * page). madvise() calls that mess with the pmap will also no longer
2215 * operate on the page.
2217 * Beyond that the page is still reasonably 'normal'. Freeing the page
2218 * will clear the flag.
2220 * This routine is used by OBJT_PHYS objects - objects using unswappable
2221 * physical memory as backing store rather then swap-backed memory and
2222 * will eventually be extended to support 4MB unmanaged physical
2225 * Caller must be holding the page busy.
2228 vm_page_unmanage(vm_page_t m
)
2230 KKASSERT(m
->flags
& PG_BUSY
);
2231 if ((m
->flags
& PG_UNMANAGED
) == 0) {
2232 if (m
->wire_count
== 0)
2235 vm_page_flag_set(m
, PG_UNMANAGED
);
2239 * Mark this page as wired down by yet another map, removing it from
2240 * paging queues as necessary.
2242 * Caller must be holding the page busy.
2245 vm_page_wire(vm_page_t m
)
2248 * Only bump the wire statistics if the page is not already wired,
2249 * and only unqueue the page if it is on some queue (if it is unmanaged
2250 * it is already off the queues). Don't do anything with fictitious
2251 * pages because they are always wired.
2253 KKASSERT(m
->flags
& PG_BUSY
);
2254 if ((m
->flags
& PG_FICTITIOUS
) == 0) {
2255 if (atomic_fetchadd_int(&m
->wire_count
, 1) == 0) {
2256 if ((m
->flags
& PG_UNMANAGED
) == 0)
2258 atomic_add_int(&vmstats
.v_wire_count
, 1);
2260 KASSERT(m
->wire_count
!= 0,
2261 ("vm_page_wire: wire_count overflow m=%p", m
));
2266 * Release one wiring of this page, potentially enabling it to be paged again.
2268 * Many pages placed on the inactive queue should actually go
2269 * into the cache, but it is difficult to figure out which. What
2270 * we do instead, if the inactive target is well met, is to put
2271 * clean pages at the head of the inactive queue instead of the tail.
2272 * This will cause them to be moved to the cache more quickly and
2273 * if not actively re-referenced, freed more quickly. If we just
2274 * stick these pages at the end of the inactive queue, heavy filesystem
2275 * meta-data accesses can cause an unnecessary paging load on memory bound
2276 * processes. This optimization causes one-time-use metadata to be
2277 * reused more quickly.
2279 * Pages marked PG_NEED_COMMIT are always activated and never placed on
2280 * the inactive queue. This helps the pageout daemon determine memory
2281 * pressure and act on out-of-memory situations more quickly.
2283 * BUT, if we are in a low-memory situation we have no choice but to
2284 * put clean pages on the cache queue.
2286 * A number of routines use vm_page_unwire() to guarantee that the page
2287 * will go into either the inactive or active queues, and will NEVER
2288 * be placed in the cache - for example, just after dirtying a page.
2289 * dirty pages in the cache are not allowed.
2291 * This routine may not block.
2294 vm_page_unwire(vm_page_t m
, int activate
)
2296 KKASSERT(m
->flags
& PG_BUSY
);
2297 if (m
->flags
& PG_FICTITIOUS
) {
2299 } else if (m
->wire_count
<= 0) {
2300 panic("vm_page_unwire: invalid wire count: %d", m
->wire_count
);
2302 if (atomic_fetchadd_int(&m
->wire_count
, -1) == 1) {
2303 atomic_add_int(&vmstats
.v_wire_count
, -1);
2304 if (m
->flags
& PG_UNMANAGED
) {
2306 } else if (activate
|| (m
->flags
& PG_NEED_COMMIT
)) {
2307 vm_page_spin_lock(m
);
2308 _vm_page_add_queue_spinlocked(m
,
2309 PQ_ACTIVE
+ m
->pc
, 0);
2310 _vm_page_and_queue_spin_unlock(m
);
2312 vm_page_spin_lock(m
);
2313 vm_page_flag_clear(m
, PG_WINATCFLS
);
2314 _vm_page_add_queue_spinlocked(m
,
2315 PQ_INACTIVE
+ m
->pc
, 0);
2316 ++vm_swapcache_inactive_heuristic
;
2317 _vm_page_and_queue_spin_unlock(m
);
2324 * Move the specified page to the inactive queue. If the page has
2325 * any associated swap, the swap is deallocated.
2327 * Normally athead is 0 resulting in LRU operation. athead is set
2328 * to 1 if we want this page to be 'as if it were placed in the cache',
2329 * except without unmapping it from the process address space.
2331 * vm_page's spinlock must be held on entry and will remain held on return.
2332 * This routine may not block.
2335 _vm_page_deactivate_locked(vm_page_t m
, int athead
)
2340 * Ignore if already inactive.
2342 if (m
->queue
- m
->pc
== PQ_INACTIVE
)
2344 _vm_page_queue_spin_lock(m
);
2345 oqueue
= _vm_page_rem_queue_spinlocked(m
);
2347 if (m
->wire_count
== 0 && (m
->flags
& PG_UNMANAGED
) == 0) {
2348 if (oqueue
== PQ_CACHE
)
2349 mycpu
->gd_cnt
.v_reactivated
++;
2350 vm_page_flag_clear(m
, PG_WINATCFLS
);
2351 _vm_page_add_queue_spinlocked(m
, PQ_INACTIVE
+ m
->pc
, athead
);
2353 ++vm_swapcache_inactive_heuristic
;
2355 /* NOTE: PQ_NONE if condition not taken */
2356 _vm_page_queue_spin_unlock(m
);
2357 /* leaves vm_page spinlocked */
2361 * Attempt to deactivate a page.
2366 vm_page_deactivate(vm_page_t m
)
2368 vm_page_spin_lock(m
);
2369 _vm_page_deactivate_locked(m
, 0);
2370 vm_page_spin_unlock(m
);
2374 vm_page_deactivate_locked(vm_page_t m
)
2376 _vm_page_deactivate_locked(m
, 0);
2380 * Attempt to move a page to PQ_CACHE.
2382 * Returns 0 on failure, 1 on success
2384 * The page should NOT be busied by the caller. This function will validate
2385 * whether the page can be safely moved to the cache.
2388 vm_page_try_to_cache(vm_page_t m
)
2390 vm_page_spin_lock(m
);
2391 if (vm_page_busy_try(m
, TRUE
)) {
2392 vm_page_spin_unlock(m
);
2395 if (m
->dirty
|| m
->hold_count
|| m
->wire_count
||
2396 (m
->flags
& (PG_UNMANAGED
| PG_NEED_COMMIT
))) {
2397 if (_vm_page_wakeup(m
)) {
2398 vm_page_spin_unlock(m
);
2401 vm_page_spin_unlock(m
);
2405 vm_page_spin_unlock(m
);
2408 * Page busied by us and no longer spinlocked. Dirty pages cannot
2409 * be moved to the cache.
2411 vm_page_test_dirty(m
);
2412 if (m
->dirty
|| (m
->flags
& PG_NEED_COMMIT
)) {
2421 * Attempt to free the page. If we cannot free it, we do nothing.
2422 * 1 is returned on success, 0 on failure.
2427 vm_page_try_to_free(vm_page_t m
)
2429 vm_page_spin_lock(m
);
2430 if (vm_page_busy_try(m
, TRUE
)) {
2431 vm_page_spin_unlock(m
);
2436 * The page can be in any state, including already being on the free
2437 * queue. Check to see if it really can be freed.
2439 if (m
->dirty
|| /* can't free if it is dirty */
2440 m
->hold_count
|| /* or held (XXX may be wrong) */
2441 m
->wire_count
|| /* or wired */
2442 (m
->flags
& (PG_UNMANAGED
| /* or unmanaged */
2443 PG_NEED_COMMIT
)) || /* or needs a commit */
2444 m
->queue
- m
->pc
== PQ_FREE
|| /* already on PQ_FREE */
2445 m
->queue
- m
->pc
== PQ_HOLD
) { /* already on PQ_HOLD */
2446 if (_vm_page_wakeup(m
)) {
2447 vm_page_spin_unlock(m
);
2450 vm_page_spin_unlock(m
);
2454 vm_page_spin_unlock(m
);
2457 * We can probably free the page.
2459 * Page busied by us and no longer spinlocked. Dirty pages will
2460 * not be freed by this function. We have to re-test the
2461 * dirty bit after cleaning out the pmaps.
2463 vm_page_test_dirty(m
);
2464 if (m
->dirty
|| (m
->flags
& PG_NEED_COMMIT
)) {
2468 vm_page_protect(m
, VM_PROT_NONE
);
2469 if (m
->dirty
|| (m
->flags
& PG_NEED_COMMIT
)) {
2480 * Put the specified page onto the page cache queue (if appropriate).
2482 * The page must be busy, and this routine will release the busy and
2483 * possibly even free the page.
2486 vm_page_cache(vm_page_t m
)
2488 if ((m
->flags
& (PG_UNMANAGED
| PG_NEED_COMMIT
)) ||
2489 m
->busy
|| m
->wire_count
|| m
->hold_count
) {
2490 kprintf("vm_page_cache: attempting to cache busy/held page\n");
2496 * Already in the cache (and thus not mapped)
2498 if ((m
->queue
- m
->pc
) == PQ_CACHE
) {
2499 KKASSERT((m
->flags
& PG_MAPPED
) == 0);
2505 * Caller is required to test m->dirty, but note that the act of
2506 * removing the page from its maps can cause it to become dirty
2507 * on an SMP system due to another cpu running in usermode.
2510 panic("vm_page_cache: caching a dirty page, pindex: %ld",
2515 * Remove all pmaps and indicate that the page is not
2516 * writeable or mapped. Our vm_page_protect() call may
2517 * have blocked (especially w/ VM_PROT_NONE), so recheck
2520 vm_page_protect(m
, VM_PROT_NONE
);
2521 if ((m
->flags
& (PG_UNMANAGED
| PG_MAPPED
)) ||
2522 m
->busy
|| m
->wire_count
|| m
->hold_count
) {
2524 } else if (m
->dirty
|| (m
->flags
& PG_NEED_COMMIT
)) {
2525 vm_page_deactivate(m
);
2528 _vm_page_and_queue_spin_lock(m
);
2529 _vm_page_rem_queue_spinlocked(m
);
2530 _vm_page_add_queue_spinlocked(m
, PQ_CACHE
+ m
->pc
, 0);
2531 _vm_page_queue_spin_unlock(m
);
2532 if (_vm_page_wakeup(m
)) {
2533 vm_page_spin_unlock(m
);
2536 vm_page_spin_unlock(m
);
2538 vm_page_free_wakeup();
2543 * vm_page_dontneed()
2545 * Cache, deactivate, or do nothing as appropriate. This routine
2546 * is typically used by madvise() MADV_DONTNEED.
2548 * Generally speaking we want to move the page into the cache so
2549 * it gets reused quickly. However, this can result in a silly syndrome
2550 * due to the page recycling too quickly. Small objects will not be
2551 * fully cached. On the otherhand, if we move the page to the inactive
2552 * queue we wind up with a problem whereby very large objects
2553 * unnecessarily blow away our inactive and cache queues.
2555 * The solution is to move the pages based on a fixed weighting. We
2556 * either leave them alone, deactivate them, or move them to the cache,
2557 * where moving them to the cache has the highest weighting.
2558 * By forcing some pages into other queues we eventually force the
2559 * system to balance the queues, potentially recovering other unrelated
2560 * space from active. The idea is to not force this to happen too
2563 * The page must be busied.
2566 vm_page_dontneed(vm_page_t m
)
2568 static int dnweight
;
2575 * occassionally leave the page alone
2577 if ((dnw
& 0x01F0) == 0 ||
2578 m
->queue
- m
->pc
== PQ_INACTIVE
||
2579 m
->queue
- m
->pc
== PQ_CACHE
2581 if (m
->act_count
>= ACT_INIT
)
2587 * If vm_page_dontneed() is inactivating a page, it must clear
2588 * the referenced flag; otherwise the pagedaemon will see references
2589 * on the page in the inactive queue and reactivate it. Until the
2590 * page can move to the cache queue, madvise's job is not done.
2592 vm_page_flag_clear(m
, PG_REFERENCED
);
2593 pmap_clear_reference(m
);
2596 vm_page_test_dirty(m
);
2598 if (m
->dirty
|| (dnw
& 0x0070) == 0) {
2600 * Deactivate the page 3 times out of 32.
2605 * Cache the page 28 times out of every 32. Note that
2606 * the page is deactivated instead of cached, but placed
2607 * at the head of the queue instead of the tail.
2611 vm_page_spin_lock(m
);
2612 _vm_page_deactivate_locked(m
, head
);
2613 vm_page_spin_unlock(m
);
2617 * These routines manipulate the 'soft busy' count for a page. A soft busy
2618 * is almost like PG_BUSY except that it allows certain compatible operations
2619 * to occur on the page while it is busy. For example, a page undergoing a
2620 * write can still be mapped read-only.
2622 * Because vm_pages can overlap buffers m->busy can be > 1. m->busy is only
2623 * adjusted while the vm_page is PG_BUSY so the flash will occur when the
2624 * busy bit is cleared.
2627 vm_page_io_start(vm_page_t m
)
2629 KASSERT(m
->flags
& PG_BUSY
, ("vm_page_io_start: page not busy!!!"));
2630 atomic_add_char(&m
->busy
, 1);
2631 vm_page_flag_set(m
, PG_SBUSY
);
2635 vm_page_io_finish(vm_page_t m
)
2637 KASSERT(m
->flags
& PG_BUSY
, ("vm_page_io_finish: page not busy!!!"));
2638 atomic_subtract_char(&m
->busy
, 1);
2640 vm_page_flag_clear(m
, PG_SBUSY
);
2644 * Indicate that a clean VM page requires a filesystem commit and cannot
2645 * be reused. Used by tmpfs.
2648 vm_page_need_commit(vm_page_t m
)
2650 vm_page_flag_set(m
, PG_NEED_COMMIT
);
2651 vm_object_set_writeable_dirty(m
->object
);
2655 vm_page_clear_commit(vm_page_t m
)
2657 vm_page_flag_clear(m
, PG_NEED_COMMIT
);
2661 * Grab a page, blocking if it is busy and allocating a page if necessary.
2662 * A busy page is returned or NULL. The page may or may not be valid and
2663 * might not be on a queue (the caller is responsible for the disposition of
2666 * If VM_ALLOC_ZERO is specified and the grab must allocate a new page, the
2667 * page will be zero'd and marked valid.
2669 * If VM_ALLOC_FORCE_ZERO is specified the page will be zero'd and marked
2670 * valid even if it already exists.
2672 * If VM_ALLOC_RETRY is specified this routine will never return NULL. Also
2673 * note that VM_ALLOC_NORMAL must be specified if VM_ALLOC_RETRY is specified.
2674 * VM_ALLOC_NULL_OK is implied when VM_ALLOC_RETRY is specified.
2676 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is
2677 * always returned if we had blocked.
2679 * This routine may not be called from an interrupt.
2681 * No other requirements.
2684 vm_page_grab(vm_object_t object
, vm_pindex_t pindex
, int allocflags
)
2690 KKASSERT(allocflags
&
2691 (VM_ALLOC_NORMAL
|VM_ALLOC_INTERRUPT
|VM_ALLOC_SYSTEM
));
2692 vm_object_hold_shared(object
);
2694 m
= vm_page_lookup_busy_try(object
, pindex
, TRUE
, &error
);
2696 vm_page_sleep_busy(m
, TRUE
, "pgrbwt");
2697 if ((allocflags
& VM_ALLOC_RETRY
) == 0) {
2702 } else if (m
== NULL
) {
2704 vm_object_upgrade(object
);
2707 if (allocflags
& VM_ALLOC_RETRY
)
2708 allocflags
|= VM_ALLOC_NULL_OK
;
2709 m
= vm_page_alloc(object
, pindex
,
2710 allocflags
& ~VM_ALLOC_RETRY
);
2714 if ((allocflags
& VM_ALLOC_RETRY
) == 0)
2723 * If VM_ALLOC_ZERO an invalid page will be zero'd and set valid.
2725 * If VM_ALLOC_FORCE_ZERO the page is unconditionally zero'd and set
2726 * valid even if already valid.
2728 * NOTE! We have removed all of the PG_ZERO optimizations and also
2729 * removed the idle zeroing code. These optimizations actually
2730 * slow things down on modern cpus because the zerod area is
2731 * likely uncached, placing a memory-access burden on the
2732 * accesors taking the fault.
2734 * By always zeroing the page in-line with the fault, no
2735 * dynamic ram reads are needed and the caches are hot, ready
2736 * for userland to access the memory.
2738 if (m
->valid
== 0) {
2739 if (allocflags
& (VM_ALLOC_ZERO
| VM_ALLOC_FORCE_ZERO
)) {
2740 pmap_zero_page(VM_PAGE_TO_PHYS(m
));
2741 m
->valid
= VM_PAGE_BITS_ALL
;
2743 } else if (allocflags
& VM_ALLOC_FORCE_ZERO
) {
2744 pmap_zero_page(VM_PAGE_TO_PHYS(m
));
2745 m
->valid
= VM_PAGE_BITS_ALL
;
2748 vm_object_drop(object
);
2753 * Mapping function for valid bits or for dirty bits in
2754 * a page. May not block.
2756 * Inputs are required to range within a page.
2762 vm_page_bits(int base
, int size
)
2768 base
+ size
<= PAGE_SIZE
,
2769 ("vm_page_bits: illegal base/size %d/%d", base
, size
)
2772 if (size
== 0) /* handle degenerate case */
2775 first_bit
= base
>> DEV_BSHIFT
;
2776 last_bit
= (base
+ size
- 1) >> DEV_BSHIFT
;
2778 return ((2 << last_bit
) - (1 << first_bit
));
2782 * Sets portions of a page valid and clean. The arguments are expected
2783 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
2784 * of any partial chunks touched by the range. The invalid portion of
2785 * such chunks will be zero'd.
2787 * NOTE: When truncating a buffer vnode_pager_setsize() will automatically
2788 * align base to DEV_BSIZE so as not to mark clean a partially
2789 * truncated device block. Otherwise the dirty page status might be
2792 * This routine may not block.
2794 * (base + size) must be less then or equal to PAGE_SIZE.
2797 _vm_page_zero_valid(vm_page_t m
, int base
, int size
)
2802 if (size
== 0) /* handle degenerate case */
2806 * If the base is not DEV_BSIZE aligned and the valid
2807 * bit is clear, we have to zero out a portion of the
2811 if ((frag
= base
& ~(DEV_BSIZE
- 1)) != base
&&
2812 (m
->valid
& (1 << (base
>> DEV_BSHIFT
))) == 0
2814 pmap_zero_page_area(
2822 * If the ending offset is not DEV_BSIZE aligned and the
2823 * valid bit is clear, we have to zero out a portion of
2827 endoff
= base
+ size
;
2829 if ((frag
= endoff
& ~(DEV_BSIZE
- 1)) != endoff
&&
2830 (m
->valid
& (1 << (endoff
>> DEV_BSHIFT
))) == 0
2832 pmap_zero_page_area(
2835 DEV_BSIZE
- (endoff
& (DEV_BSIZE
- 1))
2841 * Set valid, clear dirty bits. If validating the entire
2842 * page we can safely clear the pmap modify bit. We also
2843 * use this opportunity to clear the PG_NOSYNC flag. If a process
2844 * takes a write fault on a MAP_NOSYNC memory area the flag will
2847 * We set valid bits inclusive of any overlap, but we can only
2848 * clear dirty bits for DEV_BSIZE chunks that are fully within
2851 * Page must be busied?
2852 * No other requirements.
2855 vm_page_set_valid(vm_page_t m
, int base
, int size
)
2857 _vm_page_zero_valid(m
, base
, size
);
2858 m
->valid
|= vm_page_bits(base
, size
);
2863 * Set valid bits and clear dirty bits.
2865 * NOTE: This function does not clear the pmap modified bit.
2866 * Also note that e.g. NFS may use a byte-granular base
2869 * WARNING: Page must be busied? But vfs_clean_one_page() will call
2870 * this without necessarily busying the page (via bdwrite()).
2871 * So for now vm_token must also be held.
2873 * No other requirements.
2876 vm_page_set_validclean(vm_page_t m
, int base
, int size
)
2880 _vm_page_zero_valid(m
, base
, size
);
2881 pagebits
= vm_page_bits(base
, size
);
2882 m
->valid
|= pagebits
;
2883 m
->dirty
&= ~pagebits
;
2884 if (base
== 0 && size
== PAGE_SIZE
) {
2885 /*pmap_clear_modify(m);*/
2886 vm_page_flag_clear(m
, PG_NOSYNC
);
2891 * Set valid & dirty. Used by buwrite()
2893 * WARNING: Page must be busied? But vfs_dirty_one_page() will
2894 * call this function in buwrite() so for now vm_token must
2897 * No other requirements.
2900 vm_page_set_validdirty(vm_page_t m
, int base
, int size
)
2904 pagebits
= vm_page_bits(base
, size
);
2905 m
->valid
|= pagebits
;
2906 m
->dirty
|= pagebits
;
2908 vm_object_set_writeable_dirty(m
->object
);
2914 * NOTE: This function does not clear the pmap modified bit.
2915 * Also note that e.g. NFS may use a byte-granular base
2918 * Page must be busied?
2919 * No other requirements.
2922 vm_page_clear_dirty(vm_page_t m
, int base
, int size
)
2924 m
->dirty
&= ~vm_page_bits(base
, size
);
2925 if (base
== 0 && size
== PAGE_SIZE
) {
2926 /*pmap_clear_modify(m);*/
2927 vm_page_flag_clear(m
, PG_NOSYNC
);
2932 * Make the page all-dirty.
2934 * Also make sure the related object and vnode reflect the fact that the
2935 * object may now contain a dirty page.
2937 * Page must be busied?
2938 * No other requirements.
2941 vm_page_dirty(vm_page_t m
)
2944 int pqtype
= m
->queue
- m
->pc
;
2946 KASSERT(pqtype
!= PQ_CACHE
&& pqtype
!= PQ_FREE
,
2947 ("vm_page_dirty: page in free/cache queue!"));
2948 if (m
->dirty
!= VM_PAGE_BITS_ALL
) {
2949 m
->dirty
= VM_PAGE_BITS_ALL
;
2951 vm_object_set_writeable_dirty(m
->object
);
2956 * Invalidates DEV_BSIZE'd chunks within a page. Both the
2957 * valid and dirty bits for the effected areas are cleared.
2959 * Page must be busied?
2961 * No other requirements.
2964 vm_page_set_invalid(vm_page_t m
, int base
, int size
)
2968 bits
= vm_page_bits(base
, size
);
2971 m
->object
->generation
++;
2975 * The kernel assumes that the invalid portions of a page contain
2976 * garbage, but such pages can be mapped into memory by user code.
2977 * When this occurs, we must zero out the non-valid portions of the
2978 * page so user code sees what it expects.
2980 * Pages are most often semi-valid when the end of a file is mapped
2981 * into memory and the file's size is not page aligned.
2983 * Page must be busied?
2984 * No other requirements.
2987 vm_page_zero_invalid(vm_page_t m
, boolean_t setvalid
)
2993 * Scan the valid bits looking for invalid sections that
2994 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the
2995 * valid bit may be set ) have already been zerod by
2996 * vm_page_set_validclean().
2998 for (b
= i
= 0; i
<= PAGE_SIZE
/ DEV_BSIZE
; ++i
) {
2999 if (i
== (PAGE_SIZE
/ DEV_BSIZE
) ||
3000 (m
->valid
& (1 << i
))
3003 pmap_zero_page_area(
3006 (i
- b
) << DEV_BSHIFT
3014 * setvalid is TRUE when we can safely set the zero'd areas
3015 * as being valid. We can do this if there are no cache consistency
3016 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS.
3019 m
->valid
= VM_PAGE_BITS_ALL
;
3023 * Is a (partial) page valid? Note that the case where size == 0
3024 * will return FALSE in the degenerate case where the page is entirely
3025 * invalid, and TRUE otherwise.
3028 * No other requirements.
3031 vm_page_is_valid(vm_page_t m
, int base
, int size
)
3033 int bits
= vm_page_bits(base
, size
);
3035 if (m
->valid
&& ((m
->valid
& bits
) == bits
))
3042 * update dirty bits from pmap/mmu. May not block.
3044 * Caller must hold the page busy
3047 vm_page_test_dirty(vm_page_t m
)
3049 if ((m
->dirty
!= VM_PAGE_BITS_ALL
) && pmap_is_modified(m
)) {
3055 * Register an action, associating it with its vm_page
3058 vm_page_register_action(vm_page_action_t action
, vm_page_event_t event
)
3060 struct vm_page_action_list
*list
;
3063 hv
= (int)((intptr_t)action
->m
>> 8) & VMACTION_HMASK
;
3064 list
= &action_list
[hv
];
3066 lwkt_gettoken(&vm_token
);
3067 vm_page_flag_set(action
->m
, PG_ACTIONLIST
);
3068 action
->event
= event
;
3069 LIST_INSERT_HEAD(list
, action
, entry
);
3070 lwkt_reltoken(&vm_token
);
3074 * Unregister an action, disassociating it from its related vm_page
3077 vm_page_unregister_action(vm_page_action_t action
)
3079 struct vm_page_action_list
*list
;
3082 lwkt_gettoken(&vm_token
);
3083 if (action
->event
!= VMEVENT_NONE
) {
3084 action
->event
= VMEVENT_NONE
;
3085 LIST_REMOVE(action
, entry
);
3087 hv
= (int)((intptr_t)action
->m
>> 8) & VMACTION_HMASK
;
3088 list
= &action_list
[hv
];
3089 if (LIST_EMPTY(list
))
3090 vm_page_flag_clear(action
->m
, PG_ACTIONLIST
);
3092 lwkt_reltoken(&vm_token
);
3096 * Issue an event on a VM page. Corresponding action structures are
3097 * removed from the page's list and called.
3099 * If the vm_page has no more pending action events we clear its
3100 * PG_ACTIONLIST flag.
3103 vm_page_event_internal(vm_page_t m
, vm_page_event_t event
)
3105 struct vm_page_action_list
*list
;
3106 struct vm_page_action
*scan
;
3107 struct vm_page_action
*next
;
3111 hv
= (int)((intptr_t)m
>> 8) & VMACTION_HMASK
;
3112 list
= &action_list
[hv
];
3115 lwkt_gettoken(&vm_token
);
3116 LIST_FOREACH_MUTABLE(scan
, list
, entry
, next
) {
3118 if (scan
->event
== event
) {
3119 scan
->event
= VMEVENT_NONE
;
3120 LIST_REMOVE(scan
, entry
);
3121 scan
->func(m
, scan
);
3129 vm_page_flag_clear(m
, PG_ACTIONLIST
);
3130 lwkt_reltoken(&vm_token
);
3133 #include "opt_ddb.h"
3135 #include <sys/kernel.h>
3137 #include <ddb/ddb.h>
3139 DB_SHOW_COMMAND(page
, vm_page_print_page_info
)
3141 db_printf("vmstats.v_free_count: %d\n", vmstats
.v_free_count
);
3142 db_printf("vmstats.v_cache_count: %d\n", vmstats
.v_cache_count
);
3143 db_printf("vmstats.v_inactive_count: %d\n", vmstats
.v_inactive_count
);
3144 db_printf("vmstats.v_active_count: %d\n", vmstats
.v_active_count
);
3145 db_printf("vmstats.v_wire_count: %d\n", vmstats
.v_wire_count
);
3146 db_printf("vmstats.v_free_reserved: %d\n", vmstats
.v_free_reserved
);
3147 db_printf("vmstats.v_free_min: %d\n", vmstats
.v_free_min
);
3148 db_printf("vmstats.v_free_target: %d\n", vmstats
.v_free_target
);
3149 db_printf("vmstats.v_cache_min: %d\n", vmstats
.v_cache_min
);
3150 db_printf("vmstats.v_inactive_target: %d\n", vmstats
.v_inactive_target
);
3153 DB_SHOW_COMMAND(pageq
, vm_page_print_pageq_info
)
3156 db_printf("PQ_FREE:");
3157 for(i
=0;i
<PQ_L2_SIZE
;i
++) {
3158 db_printf(" %d", vm_page_queues
[PQ_FREE
+ i
].lcnt
);
3162 db_printf("PQ_CACHE:");
3163 for(i
=0;i
<PQ_L2_SIZE
;i
++) {
3164 db_printf(" %d", vm_page_queues
[PQ_CACHE
+ i
].lcnt
);
3168 db_printf("PQ_ACTIVE:");
3169 for(i
=0;i
<PQ_L2_SIZE
;i
++) {
3170 db_printf(" %d", vm_page_queues
[PQ_ACTIVE
+ i
].lcnt
);
3174 db_printf("PQ_INACTIVE:");
3175 for(i
=0;i
<PQ_L2_SIZE
;i
++) {
3176 db_printf(" %d", vm_page_queues
[PQ_INACTIVE
+ i
].lcnt
);