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
];
255 /* too expensive time-wise in large-mem configurations */
256 if ((vpq
->flipflop
& 15) == 0) {
257 pmap_zero_page(VM_PAGE_TO_PHYS(m
));
259 TAILQ_INSERT_TAIL(&vpq
->pl
, m
, pageq
);
263 TAILQ_INSERT_HEAD(&vpq
->pl
, m
, pageq
);
274 * Initializes the resident memory module.
276 * Preallocates memory for critical VM structures and arrays prior to
277 * kernel_map becoming available.
279 * Memory is allocated from (virtual2_start, virtual2_end) if available,
280 * otherwise memory is allocated from (virtual_start, virtual_end).
282 * On x86-64 (virtual_start, virtual_end) is only 2GB and may not be
283 * large enough to hold vm_page_array & other structures for machines with
284 * large amounts of ram, so we want to use virtual2* when available.
287 vm_page_startup(void)
289 vm_offset_t vaddr
= virtual2_start
? virtual2_start
: virtual_start
;
292 vm_paddr_t page_range
;
299 vm_paddr_t biggestone
, biggestsize
;
306 vaddr
= round_page(vaddr
);
308 for (i
= 0; phys_avail
[i
+ 1]; i
+= 2) {
309 phys_avail
[i
] = round_page64(phys_avail
[i
]);
310 phys_avail
[i
+ 1] = trunc_page64(phys_avail
[i
+ 1]);
313 for (i
= 0; phys_avail
[i
+ 1]; i
+= 2) {
314 vm_paddr_t size
= phys_avail
[i
+ 1] - phys_avail
[i
];
316 if (size
> biggestsize
) {
324 end
= phys_avail
[biggestone
+1];
325 end
= trunc_page(end
);
328 * Initialize the queue headers for the free queue, the active queue
329 * and the inactive queue.
331 vm_page_queue_init();
333 #if !defined(_KERNEL_VIRTUAL)
335 * VKERNELs don't support minidumps and as such don't need
338 * Allocate a bitmap to indicate that a random physical page
339 * needs to be included in a minidump.
341 * The amd64 port needs this to indicate which direct map pages
342 * need to be dumped, via calls to dump_add_page()/dump_drop_page().
344 * However, i386 still needs this workspace internally within the
345 * minidump code. In theory, they are not needed on i386, but are
346 * included should the sf_buf code decide to use them.
348 page_range
= phys_avail
[(nblocks
- 1) * 2 + 1] / PAGE_SIZE
;
349 vm_page_dump_size
= round_page(roundup2(page_range
, NBBY
) / NBBY
);
350 end
-= vm_page_dump_size
;
351 vm_page_dump
= (void *)pmap_map(&vaddr
, end
, end
+ vm_page_dump_size
,
352 VM_PROT_READ
| VM_PROT_WRITE
);
353 bzero((void *)vm_page_dump
, vm_page_dump_size
);
356 * Compute the number of pages of memory that will be available for
357 * use (taking into account the overhead of a page structure per
360 first_page
= phys_avail
[0] / PAGE_SIZE
;
361 page_range
= phys_avail
[(nblocks
- 1) * 2 + 1] / PAGE_SIZE
- first_page
;
362 npages
= (total
- (page_range
* sizeof(struct vm_page
))) / PAGE_SIZE
;
364 #ifndef _KERNEL_VIRTUAL
366 * (only applies to real kernels)
368 * Reserve a large amount of low memory for potential 32-bit DMA
369 * space allocations. Once device initialization is complete we
370 * release most of it, but keep (vm_dma_reserved) memory reserved
371 * for later use. Typically for X / graphics. Through trial and
372 * error we find that GPUs usually requires ~60-100MB or so.
374 * By default, 128M is left in reserve on machines with 2G+ of ram.
376 vm_low_phys_reserved
= (vm_paddr_t
)65536 << PAGE_SHIFT
;
377 if (vm_low_phys_reserved
> total
/ 4)
378 vm_low_phys_reserved
= total
/ 4;
379 if (vm_dma_reserved
== 0) {
380 vm_dma_reserved
= 128 * 1024 * 1024; /* 128MB */
381 if (vm_dma_reserved
> total
/ 16)
382 vm_dma_reserved
= total
/ 16;
385 alist_init(&vm_contig_alist
, 65536, vm_contig_ameta
,
386 ALIST_RECORDS_65536
);
389 * Initialize the mem entry structures now, and put them in the free
392 new_end
= trunc_page(end
- page_range
* sizeof(struct vm_page
));
393 mapped
= pmap_map(&vaddr
, new_end
, end
, VM_PROT_READ
| VM_PROT_WRITE
);
394 vm_page_array
= (vm_page_t
)mapped
;
396 #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL)
398 * since pmap_map on amd64 returns stuff out of a direct-map region,
399 * we have to manually add these pages to the minidump tracking so
400 * that they can be dumped, including the vm_page_array.
402 for (pa
= new_end
; pa
< phys_avail
[biggestone
+ 1]; pa
+= PAGE_SIZE
)
407 * Clear all of the page structures
409 bzero((caddr_t
) vm_page_array
, page_range
* sizeof(struct vm_page
));
410 vm_page_array_size
= page_range
;
413 * Construct the free queue(s) in ascending order (by physical
414 * address) so that the first 16MB of physical memory is allocated
415 * last rather than first. On large-memory machines, this avoids
416 * the exhaustion of low physical memory before isa_dmainit has run.
418 vmstats
.v_page_count
= 0;
419 vmstats
.v_free_count
= 0;
420 for (i
= 0; phys_avail
[i
+ 1] && npages
> 0; i
+= 2) {
425 last_pa
= phys_avail
[i
+ 1];
426 while (pa
< last_pa
&& npages
-- > 0) {
432 virtual2_start
= vaddr
;
434 virtual_start
= vaddr
;
438 * We tended to reserve a ton of memory for contigmalloc(). Now that most
439 * drivers have initialized we want to return most the remaining free
440 * reserve back to the VM page queues so they can be used for normal
443 * We leave vm_dma_reserved bytes worth of free pages in the reserve pool.
446 vm_page_startup_finish(void *dummy __unused
)
455 spin_lock(&vm_contig_spin
);
457 bfree
= alist_free_info(&vm_contig_alist
, &blk
, &count
);
458 if (bfree
<= vm_dma_reserved
/ PAGE_SIZE
)
464 * Figure out how much of the initial reserve we have to
465 * free in order to reach our target.
467 bfree
-= vm_dma_reserved
/ PAGE_SIZE
;
469 blk
+= count
- bfree
;
474 * Calculate the nearest power of 2 <= count.
476 for (xcount
= 1; xcount
<= count
; xcount
<<= 1)
479 blk
+= count
- xcount
;
483 * Allocate the pages from the alist, then free them to
484 * the normal VM page queues.
486 * Pages allocated from the alist are wired. We have to
487 * busy, unwire, and free them. We must also adjust
488 * vm_low_phys_reserved before freeing any pages to prevent
491 rblk
= alist_alloc(&vm_contig_alist
, blk
, count
);
493 kprintf("vm_page_startup_finish: Unable to return "
494 "dma space @0x%08x/%d -> 0x%08x\n",
498 atomic_add_int(&vmstats
.v_dma_pages
, -count
);
499 spin_unlock(&vm_contig_spin
);
501 m
= PHYS_TO_VM_PAGE((vm_paddr_t
)blk
<< PAGE_SHIFT
);
502 vm_low_phys_reserved
= VM_PAGE_TO_PHYS(m
);
504 vm_page_busy_wait(m
, FALSE
, "cpgfr");
505 vm_page_unwire(m
, 0);
510 spin_lock(&vm_contig_spin
);
512 spin_unlock(&vm_contig_spin
);
515 * Print out how much DMA space drivers have already allocated and
516 * how much is left over.
518 kprintf("DMA space used: %jdk, remaining available: %jdk\n",
519 (intmax_t)(vmstats
.v_dma_pages
- vm_contig_alist
.bl_free
) *
521 (intmax_t)vm_contig_alist
.bl_free
* (PAGE_SIZE
/ 1024));
523 SYSINIT(vm_pgend
, SI_SUB_PROC0_POST
, SI_ORDER_ANY
,
524 vm_page_startup_finish
, NULL
);
528 * Scan comparison function for Red-Black tree scans. An inclusive
529 * (start,end) is expected. Other fields are not used.
532 rb_vm_page_scancmp(struct vm_page
*p
, void *data
)
534 struct rb_vm_page_scan_info
*info
= data
;
536 if (p
->pindex
< info
->start_pindex
)
538 if (p
->pindex
> info
->end_pindex
)
544 rb_vm_page_compare(struct vm_page
*p1
, struct vm_page
*p2
)
546 if (p1
->pindex
< p2
->pindex
)
548 if (p1
->pindex
> p2
->pindex
)
554 vm_page_init(vm_page_t m
)
556 /* do nothing for now. Called from pmap_page_init() */
560 * Each page queue has its own spin lock, which is fairly optimal for
561 * allocating and freeing pages at least.
563 * The caller must hold the vm_page_spin_lock() before locking a vm_page's
564 * queue spinlock via this function. Also note that m->queue cannot change
565 * unless both the page and queue are locked.
569 _vm_page_queue_spin_lock(vm_page_t m
)
574 if (queue
!= PQ_NONE
) {
575 spin_lock(&vm_page_queues
[queue
].spin
);
576 KKASSERT(queue
== m
->queue
);
582 _vm_page_queue_spin_unlock(vm_page_t m
)
588 if (queue
!= PQ_NONE
)
589 spin_unlock(&vm_page_queues
[queue
].spin
);
594 _vm_page_queues_spin_lock(u_short queue
)
597 if (queue
!= PQ_NONE
)
598 spin_lock(&vm_page_queues
[queue
].spin
);
604 _vm_page_queues_spin_unlock(u_short queue
)
607 if (queue
!= PQ_NONE
)
608 spin_unlock(&vm_page_queues
[queue
].spin
);
612 vm_page_queue_spin_lock(vm_page_t m
)
614 _vm_page_queue_spin_lock(m
);
618 vm_page_queues_spin_lock(u_short queue
)
620 _vm_page_queues_spin_lock(queue
);
624 vm_page_queue_spin_unlock(vm_page_t m
)
626 _vm_page_queue_spin_unlock(m
);
630 vm_page_queues_spin_unlock(u_short queue
)
632 _vm_page_queues_spin_unlock(queue
);
636 * This locks the specified vm_page and its queue in the proper order
637 * (page first, then queue). The queue may change so the caller must
642 _vm_page_and_queue_spin_lock(vm_page_t m
)
644 vm_page_spin_lock(m
);
645 _vm_page_queue_spin_lock(m
);
650 _vm_page_and_queue_spin_unlock(vm_page_t m
)
652 _vm_page_queues_spin_unlock(m
->queue
);
653 vm_page_spin_unlock(m
);
657 vm_page_and_queue_spin_unlock(vm_page_t m
)
659 _vm_page_and_queue_spin_unlock(m
);
663 vm_page_and_queue_spin_lock(vm_page_t m
)
665 _vm_page_and_queue_spin_lock(m
);
669 * Helper function removes vm_page from its current queue.
670 * Returns the base queue the page used to be on.
672 * The vm_page and the queue must be spinlocked.
673 * This function will unlock the queue but leave the page spinlocked.
675 static __inline u_short
676 _vm_page_rem_queue_spinlocked(vm_page_t m
)
678 struct vpgqueues
*pq
;
683 if (queue
!= PQ_NONE
) {
684 pq
= &vm_page_queues
[queue
];
685 TAILQ_REMOVE(&pq
->pl
, m
, pageq
);
686 atomic_add_int(pq
->cnt
, -1);
690 if ((queue
- m
->pc
) == PQ_FREE
&& (m
->flags
& PG_ZERO
))
692 if ((queue
- m
->pc
) == PQ_CACHE
|| (queue
- m
->pc
) == PQ_FREE
)
694 vm_page_queues_spin_unlock(oqueue
); /* intended */
700 * Helper function places the vm_page on the specified queue.
702 * The vm_page must be spinlocked.
703 * This function will return with both the page and the queue locked.
706 _vm_page_add_queue_spinlocked(vm_page_t m
, u_short queue
, int athead
)
708 struct vpgqueues
*pq
;
710 KKASSERT(m
->queue
== PQ_NONE
);
712 if (queue
!= PQ_NONE
) {
713 vm_page_queues_spin_lock(queue
);
714 pq
= &vm_page_queues
[queue
];
716 atomic_add_int(pq
->cnt
, 1);
720 * Put zero'd pages on the end ( where we look for zero'd pages
721 * first ) and non-zerod pages at the head.
723 if (queue
- m
->pc
== PQ_FREE
) {
724 if (m
->flags
& PG_ZERO
) {
725 TAILQ_INSERT_TAIL(&pq
->pl
, m
, pageq
);
728 TAILQ_INSERT_HEAD(&pq
->pl
, m
, pageq
);
731 TAILQ_INSERT_HEAD(&pq
->pl
, m
, pageq
);
733 TAILQ_INSERT_TAIL(&pq
->pl
, m
, pageq
);
735 /* leave the queue spinlocked */
740 * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE)
741 * m->busy is zero. Returns TRUE if it had to sleep, FALSE if we
742 * did not. Only one sleep call will be made before returning.
744 * This function does NOT busy the page and on return the page is not
745 * guaranteed to be available.
748 vm_page_sleep_busy(vm_page_t m
, int also_m_busy
, const char *msg
)
756 if ((flags
& PG_BUSY
) == 0 &&
757 (also_m_busy
== 0 || (flags
& PG_SBUSY
) == 0)) {
760 tsleep_interlock(m
, 0);
761 if (atomic_cmpset_int(&m
->flags
, flags
,
762 flags
| PG_WANTED
| PG_REFERENCED
)) {
763 tsleep(m
, PINTERLOCKED
, msg
, 0);
770 * This calculates and returns a page color given an optional VM object and
771 * either a pindex or an iterator. We attempt to return a cpu-localized
772 * pg_color that is still roughly 16-way set-associative. The CPU topology
773 * is used if it was probed.
775 * The caller may use the returned value to index into e.g. PQ_FREE when
776 * allocating a page in order to nominally obtain pages that are hopefully
777 * already localized to the requesting cpu. This function is not able to
778 * provide any sort of guarantee of this, but does its best to improve
779 * hardware cache management performance.
781 * WARNING! The caller must mask the returned value with PQ_L2_MASK.
784 vm_get_pg_color(globaldata_t gd
, vm_object_t object
, vm_pindex_t pindex
)
791 phys_id
= get_cpu_phys_id(gd
->gd_cpuid
);
792 core_id
= get_cpu_core_id(gd
->gd_cpuid
);
793 object_pg_color
= object
? object
->pg_color
: 0;
795 if (cpu_topology_phys_ids
&& cpu_topology_core_ids
) {
796 int grpsize
= PQ_L2_SIZE
/ cpu_topology_phys_ids
;
798 if (grpsize
/ cpu_topology_core_ids
>= PQ_SET_ASSOC
) {
800 * Enough space for a full break-down.
802 pg_color
= phys_id
* grpsize
;
803 pg_color
+= core_id
* grpsize
/ cpu_topology_core_ids
;
804 pg_color
+= (pindex
+ object_pg_color
) %
805 (grpsize
/ cpu_topology_core_ids
);
808 * Not enough space, split up by physical package,
809 * then split up by core id but only down to a
810 * 16-set. If all else fails, force a 16-set.
812 pg_color
= phys_id
* grpsize
;
814 pg_color
+= 16 * (core_id
% (grpsize
/ 16));
819 pg_color
+= (pindex
+ object_pg_color
) %
824 * Unknown topology, distribute things evenly.
826 pg_color
= gd
->gd_cpuid
* PQ_L2_SIZE
/ ncpus
;
827 pg_color
+= pindex
+ object_pg_color
;
833 * Wait until PG_BUSY can be set, then set it. If also_m_busy is TRUE we
834 * also wait for m->busy to become 0 before setting PG_BUSY.
837 VM_PAGE_DEBUG_EXT(vm_page_busy_wait
)(vm_page_t m
,
838 int also_m_busy
, const char *msg
846 if (flags
& PG_BUSY
) {
847 tsleep_interlock(m
, 0);
848 if (atomic_cmpset_int(&m
->flags
, flags
,
849 flags
| PG_WANTED
| PG_REFERENCED
)) {
850 tsleep(m
, PINTERLOCKED
, msg
, 0);
852 } else if (also_m_busy
&& (flags
& PG_SBUSY
)) {
853 tsleep_interlock(m
, 0);
854 if (atomic_cmpset_int(&m
->flags
, flags
,
855 flags
| PG_WANTED
| PG_REFERENCED
)) {
856 tsleep(m
, PINTERLOCKED
, msg
, 0);
859 if (atomic_cmpset_int(&m
->flags
, flags
,
863 m
->busy_line
= lineno
;
872 * Attempt to set PG_BUSY. If also_m_busy is TRUE we only succeed if m->busy
875 * Returns non-zero on failure.
878 VM_PAGE_DEBUG_EXT(vm_page_busy_try
)(vm_page_t m
, int also_m_busy
888 if (also_m_busy
&& (flags
& PG_SBUSY
))
890 if (atomic_cmpset_int(&m
->flags
, flags
, flags
| PG_BUSY
)) {
893 m
->busy_line
= lineno
;
901 * Clear the PG_BUSY flag and return non-zero to indicate to the caller
902 * that a wakeup() should be performed.
904 * The vm_page must be spinlocked and will remain spinlocked on return.
905 * The related queue must NOT be spinlocked (which could deadlock us).
911 _vm_page_wakeup(vm_page_t m
)
918 if (atomic_cmpset_int(&m
->flags
, flags
,
919 flags
& ~(PG_BUSY
| PG_WANTED
))) {
923 return(flags
& PG_WANTED
);
927 * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This
928 * is typically the last call you make on a page before moving onto
932 vm_page_wakeup(vm_page_t m
)
934 KASSERT(m
->flags
& PG_BUSY
, ("vm_page_wakeup: page not busy!!!"));
935 vm_page_spin_lock(m
);
936 if (_vm_page_wakeup(m
)) {
937 vm_page_spin_unlock(m
);
940 vm_page_spin_unlock(m
);
945 * Holding a page keeps it from being reused. Other parts of the system
946 * can still disassociate the page from its current object and free it, or
947 * perform read or write I/O on it and/or otherwise manipulate the page,
948 * but if the page is held the VM system will leave the page and its data
949 * intact and not reuse the page for other purposes until the last hold
950 * reference is released. (see vm_page_wire() if you want to prevent the
951 * page from being disassociated from its object too).
953 * The caller must still validate the contents of the page and, if necessary,
954 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete
955 * before manipulating the page.
957 * XXX get vm_page_spin_lock() here and move FREE->HOLD if necessary
960 vm_page_hold(vm_page_t m
)
962 vm_page_spin_lock(m
);
963 atomic_add_int(&m
->hold_count
, 1);
964 if (m
->queue
- m
->pc
== PQ_FREE
) {
965 _vm_page_queue_spin_lock(m
);
966 _vm_page_rem_queue_spinlocked(m
);
967 _vm_page_add_queue_spinlocked(m
, PQ_HOLD
+ m
->pc
, 0);
968 _vm_page_queue_spin_unlock(m
);
970 vm_page_spin_unlock(m
);
974 * The opposite of vm_page_hold(). If the page is on the HOLD queue
975 * it was freed while held and must be moved back to the FREE queue.
978 vm_page_unhold(vm_page_t m
)
980 KASSERT(m
->hold_count
> 0 && m
->queue
- m
->pc
!= PQ_FREE
,
981 ("vm_page_unhold: pg %p illegal hold_count (%d) or on FREE queue (%d)",
982 m
, m
->hold_count
, m
->queue
- m
->pc
));
983 vm_page_spin_lock(m
);
984 atomic_add_int(&m
->hold_count
, -1);
985 if (m
->hold_count
== 0 && m
->queue
- m
->pc
== PQ_HOLD
) {
986 _vm_page_queue_spin_lock(m
);
987 _vm_page_rem_queue_spinlocked(m
);
988 _vm_page_add_queue_spinlocked(m
, PQ_FREE
+ m
->pc
, 0);
989 _vm_page_queue_spin_unlock(m
);
991 vm_page_spin_unlock(m
);
997 * Create a fictitious page with the specified physical address and
998 * memory attribute. The memory attribute is the only the machine-
999 * dependent aspect of a fictitious page that must be initialized.
1003 vm_page_initfake(vm_page_t m
, vm_paddr_t paddr
, vm_memattr_t memattr
)
1006 if ((m
->flags
& PG_FICTITIOUS
) != 0) {
1008 * The page's memattr might have changed since the
1009 * previous initialization. Update the pmap to the
1014 m
->phys_addr
= paddr
;
1016 /* Fictitious pages don't use "segind". */
1017 /* Fictitious pages don't use "order" or "pool". */
1018 m
->flags
= PG_FICTITIOUS
| PG_UNMANAGED
| PG_BUSY
;
1022 pmap_page_set_memattr(m
, memattr
);
1026 * Inserts the given vm_page into the object and object list.
1028 * The pagetables are not updated but will presumably fault the page
1029 * in if necessary, or if a kernel page the caller will at some point
1030 * enter the page into the kernel's pmap. We are not allowed to block
1031 * here so we *can't* do this anyway.
1033 * This routine may not block.
1034 * This routine must be called with the vm_object held.
1035 * This routine must be called with a critical section held.
1037 * This routine returns TRUE if the page was inserted into the object
1038 * successfully, and FALSE if the page already exists in the object.
1041 vm_page_insert(vm_page_t m
, vm_object_t object
, vm_pindex_t pindex
)
1043 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(object
));
1044 if (m
->object
!= NULL
)
1045 panic("vm_page_insert: already inserted");
1047 object
->generation
++;
1050 * Record the object/offset pair in this page and add the
1051 * pv_list_count of the page to the object.
1053 * The vm_page spin lock is required for interactions with the pmap.
1055 vm_page_spin_lock(m
);
1058 if (vm_page_rb_tree_RB_INSERT(&object
->rb_memq
, m
)) {
1061 vm_page_spin_unlock(m
);
1064 ++object
->resident_page_count
;
1065 ++mycpu
->gd_vmtotal
.t_rm
;
1066 /* atomic_add_int(&object->agg_pv_list_count, m->md.pv_list_count); */
1067 vm_page_spin_unlock(m
);
1070 * Since we are inserting a new and possibly dirty page,
1071 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags.
1073 if ((m
->valid
& m
->dirty
) ||
1074 (m
->flags
& (PG_WRITEABLE
| PG_NEED_COMMIT
)))
1075 vm_object_set_writeable_dirty(object
);
1078 * Checks for a swap assignment and sets PG_SWAPPED if appropriate.
1080 swap_pager_page_inserted(m
);
1085 * Removes the given vm_page_t from the (object,index) table
1087 * The underlying pmap entry (if any) is NOT removed here.
1088 * This routine may not block.
1090 * The page must be BUSY and will remain BUSY on return.
1091 * No other requirements.
1093 * NOTE: FreeBSD side effect was to unbusy the page on return. We leave
1097 vm_page_remove(vm_page_t m
)
1101 if (m
->object
== NULL
) {
1105 if ((m
->flags
& PG_BUSY
) == 0)
1106 panic("vm_page_remove: page not busy");
1110 vm_object_hold(object
);
1113 * Remove the page from the object and update the object.
1115 * The vm_page spin lock is required for interactions with the pmap.
1117 vm_page_spin_lock(m
);
1118 vm_page_rb_tree_RB_REMOVE(&object
->rb_memq
, m
);
1119 --object
->resident_page_count
;
1120 --mycpu
->gd_vmtotal
.t_rm
;
1121 /* atomic_add_int(&object->agg_pv_list_count, -m->md.pv_list_count); */
1123 vm_page_spin_unlock(m
);
1125 object
->generation
++;
1127 vm_object_drop(object
);
1131 * Locate and return the page at (object, pindex), or NULL if the
1132 * page could not be found.
1134 * The caller must hold the vm_object token.
1137 vm_page_lookup(vm_object_t object
, vm_pindex_t pindex
)
1142 * Search the hash table for this object/offset pair
1144 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object
));
1145 m
= vm_page_rb_tree_RB_LOOKUP(&object
->rb_memq
, pindex
);
1146 KKASSERT(m
== NULL
|| (m
->object
== object
&& m
->pindex
== pindex
));
1151 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait
)(struct vm_object
*object
,
1153 int also_m_busy
, const char *msg
1159 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object
));
1160 m
= vm_page_rb_tree_RB_LOOKUP(&object
->rb_memq
, pindex
);
1162 KKASSERT(m
->object
== object
&& m
->pindex
== pindex
);
1165 if (flags
& PG_BUSY
) {
1166 tsleep_interlock(m
, 0);
1167 if (atomic_cmpset_int(&m
->flags
, flags
,
1168 flags
| PG_WANTED
| PG_REFERENCED
)) {
1169 tsleep(m
, PINTERLOCKED
, msg
, 0);
1170 m
= vm_page_rb_tree_RB_LOOKUP(&object
->rb_memq
,
1173 } else if (also_m_busy
&& (flags
& PG_SBUSY
)) {
1174 tsleep_interlock(m
, 0);
1175 if (atomic_cmpset_int(&m
->flags
, flags
,
1176 flags
| PG_WANTED
| PG_REFERENCED
)) {
1177 tsleep(m
, PINTERLOCKED
, msg
, 0);
1178 m
= vm_page_rb_tree_RB_LOOKUP(&object
->rb_memq
,
1181 } else if (atomic_cmpset_int(&m
->flags
, flags
,
1183 #ifdef VM_PAGE_DEBUG
1184 m
->busy_func
= func
;
1185 m
->busy_line
= lineno
;
1194 * Attempt to lookup and busy a page.
1196 * Returns NULL if the page could not be found
1198 * Returns a vm_page and error == TRUE if the page exists but could not
1201 * Returns a vm_page and error == FALSE on success.
1204 VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try
)(struct vm_object
*object
,
1206 int also_m_busy
, int *errorp
1212 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object
));
1213 m
= vm_page_rb_tree_RB_LOOKUP(&object
->rb_memq
, pindex
);
1216 KKASSERT(m
->object
== object
&& m
->pindex
== pindex
);
1219 if (flags
& PG_BUSY
) {
1223 if (also_m_busy
&& (flags
& PG_SBUSY
)) {
1227 if (atomic_cmpset_int(&m
->flags
, flags
, flags
| PG_BUSY
)) {
1228 #ifdef VM_PAGE_DEBUG
1229 m
->busy_func
= func
;
1230 m
->busy_line
= lineno
;
1239 * Attempt to repurpose the passed-in page. If the passed-in page cannot
1240 * be repurposed it will be released, *must_reenter will be set to 1, and
1241 * this function will fall-through to vm_page_lookup_busy_try().
1243 * The passed-in page must be wired and not busy. The returned page will
1244 * be busied and not wired.
1246 * A different page may be returned. The returned page will be busied and
1249 * NULL can be returned. If so, the required page could not be busied.
1250 * The passed-in page will be unwired.
1253 vm_page_repurpose(struct vm_object
*object
, vm_pindex_t pindex
,
1254 int also_m_busy
, int *errorp
, vm_page_t m
,
1255 int *must_reenter
, int *iswired
)
1258 vm_page_busy_wait(m
, TRUE
, "biodep");
1259 if ((m
->flags
& (PG_UNMANAGED
| PG_MAPPED
| PG_FICTITIOUS
)) ||
1260 m
->busy
|| m
->wire_count
!= 1 || m
->hold_count
) {
1261 vm_page_unwire(m
, 0);
1263 /* fall through to normal lookup */
1264 } else if (m
->dirty
|| (m
->flags
& PG_NEED_COMMIT
)) {
1265 vm_page_unwire(m
, 0);
1266 vm_page_deactivate(m
);
1268 /* fall through to normal lookup */
1271 * We can safely repurpose the page. It should
1272 * already be unqueued.
1274 KKASSERT(m
->queue
== PQ_NONE
&& m
->dirty
== 0);
1278 if (vm_page_insert(m
, object
, pindex
)) {
1284 vm_page_unwire(m
, 0);
1286 /* fall through to normal lookup */
1291 m
= vm_page_lookup_busy_try(object
, pindex
, also_m_busy
, errorp
);
1297 * Caller must hold the related vm_object
1300 vm_page_next(vm_page_t m
)
1304 next
= vm_page_rb_tree_RB_NEXT(m
);
1305 if (next
&& next
->pindex
!= m
->pindex
+ 1)
1313 * Move the given vm_page from its current object to the specified
1314 * target object/offset. The page must be busy and will remain so
1317 * new_object must be held.
1318 * This routine might block. XXX ?
1320 * NOTE: Swap associated with the page must be invalidated by the move. We
1321 * have to do this for several reasons: (1) we aren't freeing the
1322 * page, (2) we are dirtying the page, (3) the VM system is probably
1323 * moving the page from object A to B, and will then later move
1324 * the backing store from A to B and we can't have a conflict.
1326 * NOTE: We *always* dirty the page. It is necessary both for the
1327 * fact that we moved it, and because we may be invalidating
1328 * swap. If the page is on the cache, we have to deactivate it
1329 * or vm_page_dirty() will panic. Dirty pages are not allowed
1333 vm_page_rename(vm_page_t m
, vm_object_t new_object
, vm_pindex_t new_pindex
)
1335 KKASSERT(m
->flags
& PG_BUSY
);
1336 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(new_object
));
1338 ASSERT_LWKT_TOKEN_HELD_EXCL(vm_object_token(m
->object
));
1341 if (vm_page_insert(m
, new_object
, new_pindex
) == FALSE
) {
1342 panic("vm_page_rename: target exists (%p,%"PRIu64
")",
1343 new_object
, new_pindex
);
1345 if (m
->queue
- m
->pc
== PQ_CACHE
)
1346 vm_page_deactivate(m
);
1351 * vm_page_unqueue() without any wakeup. This routine is used when a page
1352 * is to remain BUSYied by the caller.
1354 * This routine may not block.
1357 vm_page_unqueue_nowakeup(vm_page_t m
)
1359 vm_page_and_queue_spin_lock(m
);
1360 (void)_vm_page_rem_queue_spinlocked(m
);
1361 vm_page_spin_unlock(m
);
1365 * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon
1368 * This routine may not block.
1371 vm_page_unqueue(vm_page_t m
)
1375 vm_page_and_queue_spin_lock(m
);
1376 queue
= _vm_page_rem_queue_spinlocked(m
);
1377 if (queue
== PQ_FREE
|| queue
== PQ_CACHE
) {
1378 vm_page_spin_unlock(m
);
1379 pagedaemon_wakeup();
1381 vm_page_spin_unlock(m
);
1386 * vm_page_list_find()
1388 * Find a page on the specified queue with color optimization.
1390 * The page coloring optimization attempts to locate a page that does
1391 * not overload other nearby pages in the object in the cpu's L1 or L2
1392 * caches. We need this optimization because cpu caches tend to be
1393 * physical caches, while object spaces tend to be virtual.
1395 * The page coloring optimization also, very importantly, tries to localize
1396 * memory to cpus and physical sockets.
1398 * On MP systems each PQ_FREE and PQ_CACHE color queue has its own spinlock
1399 * and the algorithm is adjusted to localize allocations on a per-core basis.
1400 * This is done by 'twisting' the colors.
1402 * The page is returned spinlocked and removed from its queue (it will
1403 * be on PQ_NONE), or NULL. The page is not PG_BUSY'd. The caller
1404 * is responsible for dealing with the busy-page case (usually by
1405 * deactivating the page and looping).
1407 * NOTE: This routine is carefully inlined. A non-inlined version
1408 * is available for outside callers but the only critical path is
1409 * from within this source file.
1411 * NOTE: This routine assumes that the vm_pages found in PQ_CACHE and PQ_FREE
1412 * represent stable storage, allowing us to order our locks vm_page
1413 * first, then queue.
1417 _vm_page_list_find(int basequeue
, int index
, boolean_t prefer_zero
)
1423 m
= TAILQ_LAST(&vm_page_queues
[basequeue
+index
].pl
,
1426 m
= TAILQ_FIRST(&vm_page_queues
[basequeue
+index
].pl
);
1429 m
= _vm_page_list_find2(basequeue
, index
);
1432 vm_page_and_queue_spin_lock(m
);
1433 if (m
->queue
== basequeue
+ index
) {
1434 _vm_page_rem_queue_spinlocked(m
);
1435 /* vm_page_t spin held, no queue spin */
1438 vm_page_and_queue_spin_unlock(m
);
1444 * If we could not find the page in the desired queue try to find it in
1448 _vm_page_list_find2(int basequeue
, int index
)
1450 struct vpgqueues
*pq
;
1452 int pqmask
= PQ_SET_ASSOC_MASK
>> 1;
1456 index
&= PQ_L2_MASK
;
1457 pq
= &vm_page_queues
[basequeue
];
1460 * Run local sets of 16, 32, 64, 128, and the whole queue if all
1461 * else fails (PQ_L2_MASK which is 255).
1464 pqmask
= (pqmask
<< 1) | 1;
1465 for (i
= 0; i
<= pqmask
; ++i
) {
1466 pqi
= (index
& ~pqmask
) | ((index
+ i
) & pqmask
);
1467 m
= TAILQ_FIRST(&pq
[pqi
].pl
);
1469 _vm_page_and_queue_spin_lock(m
);
1470 if (m
->queue
== basequeue
+ pqi
) {
1471 _vm_page_rem_queue_spinlocked(m
);
1474 _vm_page_and_queue_spin_unlock(m
);
1479 } while (pqmask
!= PQ_L2_MASK
);
1485 * Returns a vm_page candidate for allocation. The page is not busied so
1486 * it can move around. The caller must busy the page (and typically
1487 * deactivate it if it cannot be busied!)
1489 * Returns a spinlocked vm_page that has been removed from its queue.
1492 vm_page_list_find(int basequeue
, int index
, boolean_t prefer_zero
)
1494 return(_vm_page_list_find(basequeue
, index
, prefer_zero
));
1498 * Find a page on the cache queue with color optimization, remove it
1499 * from the queue, and busy it. The returned page will not be spinlocked.
1501 * A candidate failure will be deactivated. Candidates can fail due to
1502 * being busied by someone else, in which case they will be deactivated.
1504 * This routine may not block.
1508 vm_page_select_cache(u_short pg_color
)
1513 m
= _vm_page_list_find(PQ_CACHE
, pg_color
& PQ_L2_MASK
, FALSE
);
1517 * (m) has been removed from its queue and spinlocked
1519 if (vm_page_busy_try(m
, TRUE
)) {
1520 _vm_page_deactivate_locked(m
, 0);
1521 vm_page_spin_unlock(m
);
1524 * We successfully busied the page
1526 if ((m
->flags
& (PG_UNMANAGED
| PG_NEED_COMMIT
)) == 0 &&
1527 m
->hold_count
== 0 &&
1528 m
->wire_count
== 0 &&
1529 (m
->dirty
& m
->valid
) == 0) {
1530 vm_page_spin_unlock(m
);
1531 pagedaemon_wakeup();
1536 * The page cannot be recycled, deactivate it.
1538 _vm_page_deactivate_locked(m
, 0);
1539 if (_vm_page_wakeup(m
)) {
1540 vm_page_spin_unlock(m
);
1543 vm_page_spin_unlock(m
);
1551 * Find a free or zero page, with specified preference. We attempt to
1552 * inline the nominal case and fall back to _vm_page_select_free()
1553 * otherwise. A busied page is removed from the queue and returned.
1555 * This routine may not block.
1557 static __inline vm_page_t
1558 vm_page_select_free(u_short pg_color
, boolean_t prefer_zero
)
1563 m
= _vm_page_list_find(PQ_FREE
, pg_color
& PQ_L2_MASK
,
1567 if (vm_page_busy_try(m
, TRUE
)) {
1569 * Various mechanisms such as a pmap_collect can
1570 * result in a busy page on the free queue. We
1571 * have to move the page out of the way so we can
1572 * retry the allocation. If the other thread is not
1573 * allocating the page then m->valid will remain 0 and
1574 * the pageout daemon will free the page later on.
1576 * Since we could not busy the page, however, we
1577 * cannot make assumptions as to whether the page
1578 * will be allocated by the other thread or not,
1579 * so all we can do is deactivate it to move it out
1580 * of the way. In particular, if the other thread
1581 * wires the page it may wind up on the inactive
1582 * queue and the pageout daemon will have to deal
1583 * with that case too.
1585 _vm_page_deactivate_locked(m
, 0);
1586 vm_page_spin_unlock(m
);
1589 * Theoretically if we are able to busy the page
1590 * atomic with the queue removal (using the vm_page
1591 * lock) nobody else should be able to mess with the
1594 KKASSERT((m
->flags
& (PG_UNMANAGED
|
1595 PG_NEED_COMMIT
)) == 0);
1596 KASSERT(m
->hold_count
== 0, ("m->hold_count is not zero "
1597 "pg %p q=%d flags=%08x hold=%d wire=%d",
1598 m
, m
->queue
, m
->flags
, m
->hold_count
, m
->wire_count
));
1599 KKASSERT(m
->wire_count
== 0);
1600 vm_page_spin_unlock(m
);
1601 pagedaemon_wakeup();
1603 /* return busied and removed page */
1613 * Allocate and return a memory cell associated with this VM object/offset
1614 * pair. If object is NULL an unassociated page will be allocated.
1616 * The returned page will be busied and removed from its queues. This
1617 * routine can block and may return NULL if a race occurs and the page
1618 * is found to already exist at the specified (object, pindex).
1620 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain
1621 * VM_ALLOC_QUICK like normal but cannot use cache
1622 * VM_ALLOC_SYSTEM greater free drain
1623 * VM_ALLOC_INTERRUPT allow free list to be completely drained
1624 * VM_ALLOC_ZERO advisory request for pre-zero'd page only
1625 * VM_ALLOC_FORCE_ZERO advisory request for pre-zero'd page only
1626 * VM_ALLOC_NULL_OK ok to return NULL on insertion collision
1627 * (see vm_page_grab())
1628 * VM_ALLOC_USE_GD ok to use per-gd cache
1630 * The object must be held if not NULL
1631 * This routine may not block
1633 * Additional special handling is required when called from an interrupt
1634 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache
1638 vm_page_alloc(vm_object_t object
, vm_pindex_t pindex
, int page_req
)
1640 globaldata_t gd
= mycpu
;
1647 * Special per-cpu free VM page cache. The pages are pre-busied
1648 * and pre-zerod for us.
1650 if (gd
->gd_vmpg_count
&& (page_req
& VM_ALLOC_USE_GD
)) {
1652 if (gd
->gd_vmpg_count
) {
1653 m
= gd
->gd_vmpg_array
[--gd
->gd_vmpg_count
];
1665 * CPU localization algorithm. Break the page queues up by physical
1666 * id and core id (note that two cpu threads will have the same core
1667 * id, and core_id != gd_cpuid).
1669 * This is nowhere near perfect, for example the last pindex in a
1670 * subgroup will overflow into the next cpu or package. But this
1671 * should get us good page reuse locality in heavy mixed loads.
1673 pg_color
= vm_get_pg_color(gd
, object
, pindex
);
1676 (VM_ALLOC_NORMAL
|VM_ALLOC_QUICK
|
1677 VM_ALLOC_INTERRUPT
|VM_ALLOC_SYSTEM
));
1680 * Certain system threads (pageout daemon, buf_daemon's) are
1681 * allowed to eat deeper into the free page list.
1683 if (curthread
->td_flags
& TDF_SYSTHREAD
)
1684 page_req
|= VM_ALLOC_SYSTEM
;
1687 * Impose various limitations. Note that the v_free_reserved test
1688 * must match the opposite of vm_page_count_target() to avoid
1689 * livelocks, be careful.
1692 if (vmstats
.v_free_count
>= vmstats
.v_free_reserved
||
1693 ((page_req
& VM_ALLOC_INTERRUPT
) && vmstats
.v_free_count
> 0) ||
1694 ((page_req
& VM_ALLOC_SYSTEM
) && vmstats
.v_cache_count
== 0 &&
1695 vmstats
.v_free_count
> vmstats
.v_interrupt_free_min
)
1698 * The free queue has sufficient free pages to take one out.
1700 if (page_req
& (VM_ALLOC_ZERO
| VM_ALLOC_FORCE_ZERO
))
1701 m
= vm_page_select_free(pg_color
, TRUE
);
1703 m
= vm_page_select_free(pg_color
, FALSE
);
1704 } else if (page_req
& VM_ALLOC_NORMAL
) {
1706 * Allocatable from the cache (non-interrupt only). On
1707 * success, we must free the page and try again, thus
1708 * ensuring that vmstats.v_*_free_min counters are replenished.
1711 if (curthread
->td_preempted
) {
1712 kprintf("vm_page_alloc(): warning, attempt to allocate"
1713 " cache page from preempting interrupt\n");
1716 m
= vm_page_select_cache(pg_color
);
1719 m
= vm_page_select_cache(pg_color
);
1722 * On success move the page into the free queue and loop.
1724 * Only do this if we can safely acquire the vm_object lock,
1725 * because this is effectively a random page and the caller
1726 * might be holding the lock shared, we don't want to
1730 KASSERT(m
->dirty
== 0,
1731 ("Found dirty cache page %p", m
));
1732 if ((obj
= m
->object
) != NULL
) {
1733 if (vm_object_hold_try(obj
)) {
1734 vm_page_protect(m
, VM_PROT_NONE
);
1736 /* m->object NULL here */
1737 vm_object_drop(obj
);
1739 vm_page_deactivate(m
);
1743 vm_page_protect(m
, VM_PROT_NONE
);
1750 * On failure return NULL
1752 #if defined(DIAGNOSTIC)
1753 if (vmstats
.v_cache_count
> 0)
1754 kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats
.v_cache_count
);
1756 vm_pageout_deficit
++;
1757 pagedaemon_wakeup();
1761 * No pages available, wakeup the pageout daemon and give up.
1763 vm_pageout_deficit
++;
1764 pagedaemon_wakeup();
1769 * v_free_count can race so loop if we don't find the expected
1776 * Good page found. The page has already been busied for us and
1777 * removed from its queues.
1779 KASSERT(m
->dirty
== 0,
1780 ("vm_page_alloc: free/cache page %p was dirty", m
));
1781 KKASSERT(m
->queue
== PQ_NONE
);
1787 * Initialize the structure, inheriting some flags but clearing
1788 * all the rest. The page has already been busied for us.
1790 vm_page_flag_clear(m
, ~(PG_ZERO
| PG_BUSY
| PG_SBUSY
));
1791 KKASSERT(m
->wire_count
== 0);
1792 KKASSERT(m
->busy
== 0);
1797 * Caller must be holding the object lock (asserted by
1798 * vm_page_insert()).
1800 * NOTE: Inserting a page here does not insert it into any pmaps
1801 * (which could cause us to block allocating memory).
1803 * NOTE: If no object an unassociated page is allocated, m->pindex
1804 * can be used by the caller for any purpose.
1807 if (vm_page_insert(m
, object
, pindex
) == FALSE
) {
1809 if ((page_req
& VM_ALLOC_NULL_OK
) == 0)
1810 panic("PAGE RACE %p[%ld]/%p",
1811 object
, (long)pindex
, m
);
1819 * Don't wakeup too often - wakeup the pageout daemon when
1820 * we would be nearly out of memory.
1822 pagedaemon_wakeup();
1825 * A PG_BUSY page is returned.
1831 * Returns number of pages available in our DMA memory reserve
1832 * (adjusted with vm.dma_reserved=<value>m in /boot/loader.conf)
1835 vm_contig_avail_pages(void)
1840 spin_lock(&vm_contig_spin
);
1841 bfree
= alist_free_info(&vm_contig_alist
, &blk
, &count
);
1842 spin_unlock(&vm_contig_spin
);
1848 * Attempt to allocate contiguous physical memory with the specified
1852 vm_page_alloc_contig(vm_paddr_t low
, vm_paddr_t high
,
1853 unsigned long alignment
, unsigned long boundary
,
1854 unsigned long size
, vm_memattr_t memattr
)
1860 alignment
>>= PAGE_SHIFT
;
1863 boundary
>>= PAGE_SHIFT
;
1866 size
= (size
+ PAGE_MASK
) >> PAGE_SHIFT
;
1868 spin_lock(&vm_contig_spin
);
1869 blk
= alist_alloc(&vm_contig_alist
, 0, size
);
1870 if (blk
== ALIST_BLOCK_NONE
) {
1871 spin_unlock(&vm_contig_spin
);
1873 kprintf("vm_page_alloc_contig: %ldk nospace\n",
1874 (size
+ PAGE_MASK
) * (PAGE_SIZE
/ 1024));
1878 if (high
&& ((vm_paddr_t
)(blk
+ size
) << PAGE_SHIFT
) > high
) {
1879 alist_free(&vm_contig_alist
, blk
, size
);
1880 spin_unlock(&vm_contig_spin
);
1882 kprintf("vm_page_alloc_contig: %ldk high "
1884 (size
+ PAGE_MASK
) * (PAGE_SIZE
/ 1024),
1889 spin_unlock(&vm_contig_spin
);
1890 if (vm_contig_verbose
) {
1891 kprintf("vm_page_alloc_contig: %016jx/%ldk\n",
1892 (intmax_t)(vm_paddr_t
)blk
<< PAGE_SHIFT
,
1893 (size
+ PAGE_MASK
) * (PAGE_SIZE
/ 1024));
1896 m
= PHYS_TO_VM_PAGE((vm_paddr_t
)blk
<< PAGE_SHIFT
);
1897 if (memattr
!= VM_MEMATTR_DEFAULT
)
1898 for (i
= 0;i
< size
;i
++)
1899 pmap_page_set_memattr(&m
[i
], memattr
);
1904 * Free contiguously allocated pages. The pages will be wired but not busy.
1905 * When freeing to the alist we leave them wired and not busy.
1908 vm_page_free_contig(vm_page_t m
, unsigned long size
)
1910 vm_paddr_t pa
= VM_PAGE_TO_PHYS(m
);
1911 vm_pindex_t start
= pa
>> PAGE_SHIFT
;
1912 vm_pindex_t pages
= (size
+ PAGE_MASK
) >> PAGE_SHIFT
;
1914 if (vm_contig_verbose
) {
1915 kprintf("vm_page_free_contig: %016jx/%ldk\n",
1916 (intmax_t)pa
, size
/ 1024);
1918 if (pa
< vm_low_phys_reserved
) {
1919 KKASSERT(pa
+ size
<= vm_low_phys_reserved
);
1920 spin_lock(&vm_contig_spin
);
1921 alist_free(&vm_contig_alist
, start
, pages
);
1922 spin_unlock(&vm_contig_spin
);
1925 vm_page_busy_wait(m
, FALSE
, "cpgfr");
1926 vm_page_unwire(m
, 0);
1937 * Wait for sufficient free memory for nominal heavy memory use kernel
1940 * WARNING! Be sure never to call this in any vm_pageout code path, which
1941 * will trivially deadlock the system.
1944 vm_wait_nominal(void)
1946 while (vm_page_count_min(0))
1951 * Test if vm_wait_nominal() would block.
1954 vm_test_nominal(void)
1956 if (vm_page_count_min(0))
1962 * Block until free pages are available for allocation, called in various
1963 * places before memory allocations.
1965 * The caller may loop if vm_page_count_min() == FALSE so we cannot be
1966 * more generous then that.
1972 * never wait forever
1976 lwkt_gettoken(&vm_token
);
1978 if (curthread
== pagethread
) {
1980 * The pageout daemon itself needs pages, this is bad.
1982 if (vm_page_count_min(0)) {
1983 vm_pageout_pages_needed
= 1;
1984 tsleep(&vm_pageout_pages_needed
, 0, "VMWait", timo
);
1988 * Wakeup the pageout daemon if necessary and wait.
1990 * Do not wait indefinitely for the target to be reached,
1991 * as load might prevent it from being reached any time soon.
1992 * But wait a little to try to slow down page allocations
1993 * and to give more important threads (the pagedaemon)
1994 * allocation priority.
1996 if (vm_page_count_target()) {
1997 if (vm_pages_needed
== 0) {
1998 vm_pages_needed
= 1;
1999 wakeup(&vm_pages_needed
);
2001 ++vm_pages_waiting
; /* SMP race ok */
2002 tsleep(&vmstats
.v_free_count
, 0, "vmwait", timo
);
2005 lwkt_reltoken(&vm_token
);
2009 * Block until free pages are available for allocation
2011 * Called only from vm_fault so that processes page faulting can be
2015 vm_wait_pfault(void)
2018 * Wakeup the pageout daemon if necessary and wait.
2020 * Do not wait indefinitely for the target to be reached,
2021 * as load might prevent it from being reached any time soon.
2022 * But wait a little to try to slow down page allocations
2023 * and to give more important threads (the pagedaemon)
2024 * allocation priority.
2026 if (vm_page_count_min(0)) {
2027 lwkt_gettoken(&vm_token
);
2028 while (vm_page_count_severe()) {
2029 if (vm_page_count_target()) {
2030 if (vm_pages_needed
== 0) {
2031 vm_pages_needed
= 1;
2032 wakeup(&vm_pages_needed
);
2034 ++vm_pages_waiting
; /* SMP race ok */
2035 tsleep(&vmstats
.v_free_count
, 0, "pfault", hz
);
2038 lwkt_reltoken(&vm_token
);
2043 * Put the specified page on the active list (if appropriate). Ensure
2044 * that act_count is at least ACT_INIT but do not otherwise mess with it.
2046 * The caller should be holding the page busied ? XXX
2047 * This routine may not block.
2050 vm_page_activate(vm_page_t m
)
2054 vm_page_spin_lock(m
);
2055 if (m
->queue
- m
->pc
!= PQ_ACTIVE
) {
2056 _vm_page_queue_spin_lock(m
);
2057 oqueue
= _vm_page_rem_queue_spinlocked(m
);
2058 /* page is left spinlocked, queue is unlocked */
2060 if (oqueue
== PQ_CACHE
)
2061 mycpu
->gd_cnt
.v_reactivated
++;
2062 if (m
->wire_count
== 0 && (m
->flags
& PG_UNMANAGED
) == 0) {
2063 if (m
->act_count
< ACT_INIT
)
2064 m
->act_count
= ACT_INIT
;
2065 _vm_page_add_queue_spinlocked(m
, PQ_ACTIVE
+ m
->pc
, 0);
2067 _vm_page_and_queue_spin_unlock(m
);
2068 if (oqueue
== PQ_CACHE
|| oqueue
== PQ_FREE
)
2069 pagedaemon_wakeup();
2071 if (m
->act_count
< ACT_INIT
)
2072 m
->act_count
= ACT_INIT
;
2073 vm_page_spin_unlock(m
);
2078 * Helper routine for vm_page_free_toq() and vm_page_cache(). This
2079 * routine is called when a page has been added to the cache or free
2082 * This routine may not block.
2084 static __inline
void
2085 vm_page_free_wakeup(void)
2088 * If the pageout daemon itself needs pages, then tell it that
2089 * there are some free.
2091 if (vm_pageout_pages_needed
&&
2092 vmstats
.v_cache_count
+ vmstats
.v_free_count
>=
2093 vmstats
.v_pageout_free_min
2095 vm_pageout_pages_needed
= 0;
2096 wakeup(&vm_pageout_pages_needed
);
2100 * Wakeup processes that are waiting on memory.
2102 * Generally speaking we want to wakeup stuck processes as soon as
2103 * possible. !vm_page_count_min(0) is the absolute minimum point
2104 * where we can do this. Wait a bit longer to reduce degenerate
2105 * re-blocking (vm_page_free_hysteresis). The target check is just
2106 * to make sure the min-check w/hysteresis does not exceed the
2109 if (vm_pages_waiting
) {
2110 if (!vm_page_count_min(vm_page_free_hysteresis
) ||
2111 !vm_page_count_target()) {
2112 vm_pages_waiting
= 0;
2113 wakeup(&vmstats
.v_free_count
);
2114 ++mycpu
->gd_cnt
.v_ppwakeups
;
2117 if (!vm_page_count_target()) {
2119 * Plenty of pages are free, wakeup everyone.
2121 vm_pages_waiting
= 0;
2122 wakeup(&vmstats
.v_free_count
);
2123 ++mycpu
->gd_cnt
.v_ppwakeups
;
2124 } else if (!vm_page_count_min(0)) {
2126 * Some pages are free, wakeup someone.
2128 int wcount
= vm_pages_waiting
;
2131 vm_pages_waiting
= wcount
;
2132 wakeup_one(&vmstats
.v_free_count
);
2133 ++mycpu
->gd_cnt
.v_ppwakeups
;
2140 * Returns the given page to the PQ_FREE or PQ_HOLD list and disassociates
2141 * it from its VM object.
2143 * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on
2144 * return (the page will have been freed).
2147 vm_page_free_toq(vm_page_t m
)
2149 mycpu
->gd_cnt
.v_tfree
++;
2150 KKASSERT((m
->flags
& PG_MAPPED
) == 0);
2151 KKASSERT(m
->flags
& PG_BUSY
);
2153 if (m
->busy
|| ((m
->queue
- m
->pc
) == PQ_FREE
)) {
2154 kprintf("vm_page_free: pindex(%lu), busy(%d), "
2155 "PG_BUSY(%d), hold(%d)\n",
2156 (u_long
)m
->pindex
, m
->busy
,
2157 ((m
->flags
& PG_BUSY
) ? 1 : 0), m
->hold_count
);
2158 if ((m
->queue
- m
->pc
) == PQ_FREE
)
2159 panic("vm_page_free: freeing free page");
2161 panic("vm_page_free: freeing busy page");
2165 * Remove from object, spinlock the page and its queues and
2166 * remove from any queue. No queue spinlock will be held
2167 * after this section (because the page was removed from any
2171 vm_page_and_queue_spin_lock(m
);
2172 _vm_page_rem_queue_spinlocked(m
);
2175 * No further management of fictitious pages occurs beyond object
2176 * and queue removal.
2178 if ((m
->flags
& PG_FICTITIOUS
) != 0) {
2179 vm_page_spin_unlock(m
);
2187 if (m
->wire_count
!= 0) {
2188 if (m
->wire_count
> 1) {
2190 "vm_page_free: invalid wire count (%d), pindex: 0x%lx",
2191 m
->wire_count
, (long)m
->pindex
);
2193 panic("vm_page_free: freeing wired page");
2197 * Clear the UNMANAGED flag when freeing an unmanaged page.
2198 * Clear the NEED_COMMIT flag
2200 if (m
->flags
& PG_UNMANAGED
)
2201 vm_page_flag_clear(m
, PG_UNMANAGED
);
2202 if (m
->flags
& PG_NEED_COMMIT
)
2203 vm_page_flag_clear(m
, PG_NEED_COMMIT
);
2205 if (m
->hold_count
!= 0) {
2206 vm_page_flag_clear(m
, PG_ZERO
);
2207 _vm_page_add_queue_spinlocked(m
, PQ_HOLD
+ m
->pc
, 0);
2209 _vm_page_add_queue_spinlocked(m
, PQ_FREE
+ m
->pc
, 0);
2213 * This sequence allows us to clear PG_BUSY while still holding
2214 * its spin lock, which reduces contention vs allocators. We
2215 * must not leave the queue locked or _vm_page_wakeup() may
2218 _vm_page_queue_spin_unlock(m
);
2219 if (_vm_page_wakeup(m
)) {
2220 vm_page_spin_unlock(m
);
2223 vm_page_spin_unlock(m
);
2225 vm_page_free_wakeup();
2229 * vm_page_free_fromq_fast()
2231 * Remove a non-zero page from one of the free queues; the page is removed for
2232 * zeroing, so do not issue a wakeup.
2234 * Our zeroidle code is now per-cpu so only do a limited scan. We try to
2235 * stay within a single cpu's domain but we do a little statistical
2236 * improvement by encompassing two cpu's domains worst-case.
2239 vm_page_free_fromq_fast(void)
2241 globaldata_t gd
= mycpu
;
2247 qi
= vm_get_pg_color(gd
, NULL
, ++gd
->gd_quick_color
);
2248 qi
= qi
& PQ_L2_MASK
;
2251 * 16 = one cpu's domain
2252 * 32 = two cpu's domains
2253 * (note masking at bottom of loop!)
2255 for (i
= 0; i
< 10; ++i
) {
2256 m
= vm_page_list_find(PQ_FREE
, qi
, FALSE
);
2257 /* page is returned spinlocked and removed from its queue */
2259 if (vm_page_busy_try(m
, TRUE
)) {
2261 * We were unable to busy the page, deactivate
2264 _vm_page_deactivate_locked(m
, 0);
2265 vm_page_spin_unlock(m
);
2266 } else if (m
->flags
& PG_ZERO
) {
2268 * The page is already PG_ZERO, requeue it
2271 _vm_page_add_queue_spinlocked(m
,
2274 vm_page_queue_spin_unlock(m
);
2275 if (_vm_page_wakeup(m
)) {
2276 vm_page_spin_unlock(m
);
2279 vm_page_spin_unlock(m
);
2283 * The page is not PG_ZERO'd so return it.
2285 KKASSERT((m
->flags
& (PG_UNMANAGED
|
2286 PG_NEED_COMMIT
)) == 0);
2287 KKASSERT(m
->hold_count
== 0);
2288 KKASSERT(m
->wire_count
== 0);
2289 vm_page_spin_unlock(m
);
2299 * vm_page_unmanage()
2301 * Prevent PV management from being done on the page. The page is
2302 * removed from the paging queues as if it were wired, and as a
2303 * consequence of no longer being managed the pageout daemon will not
2304 * touch it (since there is no way to locate the pte mappings for the
2305 * page). madvise() calls that mess with the pmap will also no longer
2306 * operate on the page.
2308 * Beyond that the page is still reasonably 'normal'. Freeing the page
2309 * will clear the flag.
2311 * This routine is used by OBJT_PHYS objects - objects using unswappable
2312 * physical memory as backing store rather then swap-backed memory and
2313 * will eventually be extended to support 4MB unmanaged physical
2316 * Caller must be holding the page busy.
2319 vm_page_unmanage(vm_page_t m
)
2321 KKASSERT(m
->flags
& PG_BUSY
);
2322 if ((m
->flags
& PG_UNMANAGED
) == 0) {
2323 if (m
->wire_count
== 0)
2326 vm_page_flag_set(m
, PG_UNMANAGED
);
2330 * Mark this page as wired down by yet another map, removing it from
2331 * paging queues as necessary.
2333 * Caller must be holding the page busy.
2336 vm_page_wire(vm_page_t m
)
2339 * Only bump the wire statistics if the page is not already wired,
2340 * and only unqueue the page if it is on some queue (if it is unmanaged
2341 * it is already off the queues). Don't do anything with fictitious
2342 * pages because they are always wired.
2344 KKASSERT(m
->flags
& PG_BUSY
);
2345 if ((m
->flags
& PG_FICTITIOUS
) == 0) {
2346 if (atomic_fetchadd_int(&m
->wire_count
, 1) == 0) {
2347 if ((m
->flags
& PG_UNMANAGED
) == 0)
2349 atomic_add_int(&vmstats
.v_wire_count
, 1);
2351 KASSERT(m
->wire_count
!= 0,
2352 ("vm_page_wire: wire_count overflow m=%p", m
));
2357 * Release one wiring of this page, potentially enabling it to be paged again.
2359 * Many pages placed on the inactive queue should actually go
2360 * into the cache, but it is difficult to figure out which. What
2361 * we do instead, if the inactive target is well met, is to put
2362 * clean pages at the head of the inactive queue instead of the tail.
2363 * This will cause them to be moved to the cache more quickly and
2364 * if not actively re-referenced, freed more quickly. If we just
2365 * stick these pages at the end of the inactive queue, heavy filesystem
2366 * meta-data accesses can cause an unnecessary paging load on memory bound
2367 * processes. This optimization causes one-time-use metadata to be
2368 * reused more quickly.
2370 * Pages marked PG_NEED_COMMIT are always activated and never placed on
2371 * the inactive queue. This helps the pageout daemon determine memory
2372 * pressure and act on out-of-memory situations more quickly.
2374 * BUT, if we are in a low-memory situation we have no choice but to
2375 * put clean pages on the cache queue.
2377 * A number of routines use vm_page_unwire() to guarantee that the page
2378 * will go into either the inactive or active queues, and will NEVER
2379 * be placed in the cache - for example, just after dirtying a page.
2380 * dirty pages in the cache are not allowed.
2382 * This routine may not block.
2385 vm_page_unwire(vm_page_t m
, int activate
)
2387 KKASSERT(m
->flags
& PG_BUSY
);
2388 if (m
->flags
& PG_FICTITIOUS
) {
2390 } else if (m
->wire_count
<= 0) {
2391 panic("vm_page_unwire: invalid wire count: %d", m
->wire_count
);
2393 if (atomic_fetchadd_int(&m
->wire_count
, -1) == 1) {
2394 atomic_add_int(&vmstats
.v_wire_count
, -1);
2395 if (m
->flags
& PG_UNMANAGED
) {
2397 } else if (activate
|| (m
->flags
& PG_NEED_COMMIT
)) {
2398 vm_page_spin_lock(m
);
2399 _vm_page_add_queue_spinlocked(m
,
2400 PQ_ACTIVE
+ m
->pc
, 0);
2401 _vm_page_and_queue_spin_unlock(m
);
2403 vm_page_spin_lock(m
);
2404 vm_page_flag_clear(m
, PG_WINATCFLS
);
2405 _vm_page_add_queue_spinlocked(m
,
2406 PQ_INACTIVE
+ m
->pc
, 0);
2407 ++vm_swapcache_inactive_heuristic
;
2408 _vm_page_and_queue_spin_unlock(m
);
2415 * Move the specified page to the inactive queue. If the page has
2416 * any associated swap, the swap is deallocated.
2418 * Normally athead is 0 resulting in LRU operation. athead is set
2419 * to 1 if we want this page to be 'as if it were placed in the cache',
2420 * except without unmapping it from the process address space.
2422 * vm_page's spinlock must be held on entry and will remain held on return.
2423 * This routine may not block.
2426 _vm_page_deactivate_locked(vm_page_t m
, int athead
)
2431 * Ignore if already inactive.
2433 if (m
->queue
- m
->pc
== PQ_INACTIVE
)
2435 _vm_page_queue_spin_lock(m
);
2436 oqueue
= _vm_page_rem_queue_spinlocked(m
);
2438 if (m
->wire_count
== 0 && (m
->flags
& PG_UNMANAGED
) == 0) {
2439 if (oqueue
== PQ_CACHE
)
2440 mycpu
->gd_cnt
.v_reactivated
++;
2441 vm_page_flag_clear(m
, PG_WINATCFLS
);
2442 _vm_page_add_queue_spinlocked(m
, PQ_INACTIVE
+ m
->pc
, athead
);
2444 ++vm_swapcache_inactive_heuristic
;
2446 /* NOTE: PQ_NONE if condition not taken */
2447 _vm_page_queue_spin_unlock(m
);
2448 /* leaves vm_page spinlocked */
2452 * Attempt to deactivate a page.
2457 vm_page_deactivate(vm_page_t m
)
2459 vm_page_spin_lock(m
);
2460 _vm_page_deactivate_locked(m
, 0);
2461 vm_page_spin_unlock(m
);
2465 vm_page_deactivate_locked(vm_page_t m
)
2467 _vm_page_deactivate_locked(m
, 0);
2471 * Attempt to move a page to PQ_CACHE.
2473 * Returns 0 on failure, 1 on success
2475 * The page should NOT be busied by the caller. This function will validate
2476 * whether the page can be safely moved to the cache.
2479 vm_page_try_to_cache(vm_page_t m
)
2481 vm_page_spin_lock(m
);
2482 if (vm_page_busy_try(m
, TRUE
)) {
2483 vm_page_spin_unlock(m
);
2486 if (m
->dirty
|| m
->hold_count
|| m
->wire_count
||
2487 (m
->flags
& (PG_UNMANAGED
| PG_NEED_COMMIT
))) {
2488 if (_vm_page_wakeup(m
)) {
2489 vm_page_spin_unlock(m
);
2492 vm_page_spin_unlock(m
);
2496 vm_page_spin_unlock(m
);
2499 * Page busied by us and no longer spinlocked. Dirty pages cannot
2500 * be moved to the cache.
2502 vm_page_test_dirty(m
);
2503 if (m
->dirty
|| (m
->flags
& PG_NEED_COMMIT
)) {
2512 * Attempt to free the page. If we cannot free it, we do nothing.
2513 * 1 is returned on success, 0 on failure.
2518 vm_page_try_to_free(vm_page_t m
)
2520 vm_page_spin_lock(m
);
2521 if (vm_page_busy_try(m
, TRUE
)) {
2522 vm_page_spin_unlock(m
);
2527 * The page can be in any state, including already being on the free
2528 * queue. Check to see if it really can be freed.
2530 if (m
->dirty
|| /* can't free if it is dirty */
2531 m
->hold_count
|| /* or held (XXX may be wrong) */
2532 m
->wire_count
|| /* or wired */
2533 (m
->flags
& (PG_UNMANAGED
| /* or unmanaged */
2534 PG_NEED_COMMIT
)) || /* or needs a commit */
2535 m
->queue
- m
->pc
== PQ_FREE
|| /* already on PQ_FREE */
2536 m
->queue
- m
->pc
== PQ_HOLD
) { /* already on PQ_HOLD */
2537 if (_vm_page_wakeup(m
)) {
2538 vm_page_spin_unlock(m
);
2541 vm_page_spin_unlock(m
);
2545 vm_page_spin_unlock(m
);
2548 * We can probably free the page.
2550 * Page busied by us and no longer spinlocked. Dirty pages will
2551 * not be freed by this function. We have to re-test the
2552 * dirty bit after cleaning out the pmaps.
2554 vm_page_test_dirty(m
);
2555 if (m
->dirty
|| (m
->flags
& PG_NEED_COMMIT
)) {
2559 vm_page_protect(m
, VM_PROT_NONE
);
2560 if (m
->dirty
|| (m
->flags
& PG_NEED_COMMIT
)) {
2571 * Put the specified page onto the page cache queue (if appropriate).
2573 * The page must be busy, and this routine will release the busy and
2574 * possibly even free the page.
2577 vm_page_cache(vm_page_t m
)
2579 if ((m
->flags
& (PG_UNMANAGED
| PG_NEED_COMMIT
)) ||
2580 m
->busy
|| m
->wire_count
|| m
->hold_count
) {
2581 kprintf("vm_page_cache: attempting to cache busy/held page\n");
2587 * Already in the cache (and thus not mapped)
2589 if ((m
->queue
- m
->pc
) == PQ_CACHE
) {
2590 KKASSERT((m
->flags
& PG_MAPPED
) == 0);
2596 * Caller is required to test m->dirty, but note that the act of
2597 * removing the page from its maps can cause it to become dirty
2598 * on an SMP system due to another cpu running in usermode.
2601 panic("vm_page_cache: caching a dirty page, pindex: %ld",
2606 * Remove all pmaps and indicate that the page is not
2607 * writeable or mapped. Our vm_page_protect() call may
2608 * have blocked (especially w/ VM_PROT_NONE), so recheck
2611 vm_page_protect(m
, VM_PROT_NONE
);
2612 if ((m
->flags
& (PG_UNMANAGED
| PG_MAPPED
)) ||
2613 m
->busy
|| m
->wire_count
|| m
->hold_count
) {
2615 } else if (m
->dirty
|| (m
->flags
& PG_NEED_COMMIT
)) {
2616 vm_page_deactivate(m
);
2619 _vm_page_and_queue_spin_lock(m
);
2620 _vm_page_rem_queue_spinlocked(m
);
2621 _vm_page_add_queue_spinlocked(m
, PQ_CACHE
+ m
->pc
, 0);
2622 _vm_page_queue_spin_unlock(m
);
2623 if (_vm_page_wakeup(m
)) {
2624 vm_page_spin_unlock(m
);
2627 vm_page_spin_unlock(m
);
2629 vm_page_free_wakeup();
2634 * vm_page_dontneed()
2636 * Cache, deactivate, or do nothing as appropriate. This routine
2637 * is typically used by madvise() MADV_DONTNEED.
2639 * Generally speaking we want to move the page into the cache so
2640 * it gets reused quickly. However, this can result in a silly syndrome
2641 * due to the page recycling too quickly. Small objects will not be
2642 * fully cached. On the otherhand, if we move the page to the inactive
2643 * queue we wind up with a problem whereby very large objects
2644 * unnecessarily blow away our inactive and cache queues.
2646 * The solution is to move the pages based on a fixed weighting. We
2647 * either leave them alone, deactivate them, or move them to the cache,
2648 * where moving them to the cache has the highest weighting.
2649 * By forcing some pages into other queues we eventually force the
2650 * system to balance the queues, potentially recovering other unrelated
2651 * space from active. The idea is to not force this to happen too
2654 * The page must be busied.
2657 vm_page_dontneed(vm_page_t m
)
2659 static int dnweight
;
2666 * occassionally leave the page alone
2668 if ((dnw
& 0x01F0) == 0 ||
2669 m
->queue
- m
->pc
== PQ_INACTIVE
||
2670 m
->queue
- m
->pc
== PQ_CACHE
2672 if (m
->act_count
>= ACT_INIT
)
2678 * If vm_page_dontneed() is inactivating a page, it must clear
2679 * the referenced flag; otherwise the pagedaemon will see references
2680 * on the page in the inactive queue and reactivate it. Until the
2681 * page can move to the cache queue, madvise's job is not done.
2683 vm_page_flag_clear(m
, PG_REFERENCED
);
2684 pmap_clear_reference(m
);
2687 vm_page_test_dirty(m
);
2689 if (m
->dirty
|| (dnw
& 0x0070) == 0) {
2691 * Deactivate the page 3 times out of 32.
2696 * Cache the page 28 times out of every 32. Note that
2697 * the page is deactivated instead of cached, but placed
2698 * at the head of the queue instead of the tail.
2702 vm_page_spin_lock(m
);
2703 _vm_page_deactivate_locked(m
, head
);
2704 vm_page_spin_unlock(m
);
2708 * These routines manipulate the 'soft busy' count for a page. A soft busy
2709 * is almost like PG_BUSY except that it allows certain compatible operations
2710 * to occur on the page while it is busy. For example, a page undergoing a
2711 * write can still be mapped read-only.
2713 * Because vm_pages can overlap buffers m->busy can be > 1. m->busy is only
2714 * adjusted while the vm_page is PG_BUSY so the flash will occur when the
2715 * busy bit is cleared.
2718 vm_page_io_start(vm_page_t m
)
2720 KASSERT(m
->flags
& PG_BUSY
, ("vm_page_io_start: page not busy!!!"));
2721 atomic_add_char(&m
->busy
, 1);
2722 vm_page_flag_set(m
, PG_SBUSY
);
2726 vm_page_io_finish(vm_page_t m
)
2728 KASSERT(m
->flags
& PG_BUSY
, ("vm_page_io_finish: page not busy!!!"));
2729 atomic_subtract_char(&m
->busy
, 1);
2731 vm_page_flag_clear(m
, PG_SBUSY
);
2735 * Indicate that a clean VM page requires a filesystem commit and cannot
2736 * be reused. Used by tmpfs.
2739 vm_page_need_commit(vm_page_t m
)
2741 vm_page_flag_set(m
, PG_NEED_COMMIT
);
2742 vm_object_set_writeable_dirty(m
->object
);
2746 vm_page_clear_commit(vm_page_t m
)
2748 vm_page_flag_clear(m
, PG_NEED_COMMIT
);
2752 * Grab a page, blocking if it is busy and allocating a page if necessary.
2753 * A busy page is returned or NULL. The page may or may not be valid and
2754 * might not be on a queue (the caller is responsible for the disposition of
2757 * If VM_ALLOC_ZERO is specified and the grab must allocate a new page, the
2758 * page will be zero'd and marked valid.
2760 * If VM_ALLOC_FORCE_ZERO is specified the page will be zero'd and marked
2761 * valid even if it already exists.
2763 * If VM_ALLOC_RETRY is specified this routine will never return NULL. Also
2764 * note that VM_ALLOC_NORMAL must be specified if VM_ALLOC_RETRY is specified.
2765 * VM_ALLOC_NULL_OK is implied when VM_ALLOC_RETRY is specified.
2767 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is
2768 * always returned if we had blocked.
2770 * This routine may not be called from an interrupt.
2772 * PG_ZERO is *ALWAYS* cleared by this routine.
2774 * No other requirements.
2777 vm_page_grab(vm_object_t object
, vm_pindex_t pindex
, int allocflags
)
2783 KKASSERT(allocflags
&
2784 (VM_ALLOC_NORMAL
|VM_ALLOC_INTERRUPT
|VM_ALLOC_SYSTEM
));
2785 vm_object_hold_shared(object
);
2787 m
= vm_page_lookup_busy_try(object
, pindex
, TRUE
, &error
);
2789 vm_page_sleep_busy(m
, TRUE
, "pgrbwt");
2790 if ((allocflags
& VM_ALLOC_RETRY
) == 0) {
2795 } else if (m
== NULL
) {
2797 vm_object_upgrade(object
);
2800 if (allocflags
& VM_ALLOC_RETRY
)
2801 allocflags
|= VM_ALLOC_NULL_OK
;
2802 m
= vm_page_alloc(object
, pindex
,
2803 allocflags
& ~VM_ALLOC_RETRY
);
2807 if ((allocflags
& VM_ALLOC_RETRY
) == 0)
2816 * If VM_ALLOC_ZERO an invalid page will be zero'd and set valid.
2818 * If VM_ALLOC_FORCE_ZERO the page is unconditionally zero'd and set
2819 * valid even if already valid.
2821 if (m
->valid
== 0) {
2822 if (allocflags
& (VM_ALLOC_ZERO
| VM_ALLOC_FORCE_ZERO
)) {
2823 if ((m
->flags
& PG_ZERO
) == 0)
2824 pmap_zero_page(VM_PAGE_TO_PHYS(m
));
2825 m
->valid
= VM_PAGE_BITS_ALL
;
2827 } else if (allocflags
& VM_ALLOC_FORCE_ZERO
) {
2828 pmap_zero_page(VM_PAGE_TO_PHYS(m
));
2829 m
->valid
= VM_PAGE_BITS_ALL
;
2831 vm_page_flag_clear(m
, PG_ZERO
);
2833 vm_object_drop(object
);
2838 * Mapping function for valid bits or for dirty bits in
2839 * a page. May not block.
2841 * Inputs are required to range within a page.
2847 vm_page_bits(int base
, int size
)
2853 base
+ size
<= PAGE_SIZE
,
2854 ("vm_page_bits: illegal base/size %d/%d", base
, size
)
2857 if (size
== 0) /* handle degenerate case */
2860 first_bit
= base
>> DEV_BSHIFT
;
2861 last_bit
= (base
+ size
- 1) >> DEV_BSHIFT
;
2863 return ((2 << last_bit
) - (1 << first_bit
));
2867 * Sets portions of a page valid and clean. The arguments are expected
2868 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
2869 * of any partial chunks touched by the range. The invalid portion of
2870 * such chunks will be zero'd.
2872 * NOTE: When truncating a buffer vnode_pager_setsize() will automatically
2873 * align base to DEV_BSIZE so as not to mark clean a partially
2874 * truncated device block. Otherwise the dirty page status might be
2877 * This routine may not block.
2879 * (base + size) must be less then or equal to PAGE_SIZE.
2882 _vm_page_zero_valid(vm_page_t m
, int base
, int size
)
2887 if (size
== 0) /* handle degenerate case */
2891 * If the base is not DEV_BSIZE aligned and the valid
2892 * bit is clear, we have to zero out a portion of the
2896 if ((frag
= base
& ~(DEV_BSIZE
- 1)) != base
&&
2897 (m
->valid
& (1 << (base
>> DEV_BSHIFT
))) == 0
2899 pmap_zero_page_area(
2907 * If the ending offset is not DEV_BSIZE aligned and the
2908 * valid bit is clear, we have to zero out a portion of
2912 endoff
= base
+ size
;
2914 if ((frag
= endoff
& ~(DEV_BSIZE
- 1)) != endoff
&&
2915 (m
->valid
& (1 << (endoff
>> DEV_BSHIFT
))) == 0
2917 pmap_zero_page_area(
2920 DEV_BSIZE
- (endoff
& (DEV_BSIZE
- 1))
2926 * Set valid, clear dirty bits. If validating the entire
2927 * page we can safely clear the pmap modify bit. We also
2928 * use this opportunity to clear the PG_NOSYNC flag. If a process
2929 * takes a write fault on a MAP_NOSYNC memory area the flag will
2932 * We set valid bits inclusive of any overlap, but we can only
2933 * clear dirty bits for DEV_BSIZE chunks that are fully within
2936 * Page must be busied?
2937 * No other requirements.
2940 vm_page_set_valid(vm_page_t m
, int base
, int size
)
2942 _vm_page_zero_valid(m
, base
, size
);
2943 m
->valid
|= vm_page_bits(base
, size
);
2948 * Set valid bits and clear dirty bits.
2950 * NOTE: This function does not clear the pmap modified bit.
2951 * Also note that e.g. NFS may use a byte-granular base
2954 * WARNING: Page must be busied? But vfs_clean_one_page() will call
2955 * this without necessarily busying the page (via bdwrite()).
2956 * So for now vm_token must also be held.
2958 * No other requirements.
2961 vm_page_set_validclean(vm_page_t m
, int base
, int size
)
2965 _vm_page_zero_valid(m
, base
, size
);
2966 pagebits
= vm_page_bits(base
, size
);
2967 m
->valid
|= pagebits
;
2968 m
->dirty
&= ~pagebits
;
2969 if (base
== 0 && size
== PAGE_SIZE
) {
2970 /*pmap_clear_modify(m);*/
2971 vm_page_flag_clear(m
, PG_NOSYNC
);
2976 * Set valid & dirty. Used by buwrite()
2978 * WARNING: Page must be busied? But vfs_dirty_one_page() will
2979 * call this function in buwrite() so for now vm_token must
2982 * No other requirements.
2985 vm_page_set_validdirty(vm_page_t m
, int base
, int size
)
2989 pagebits
= vm_page_bits(base
, size
);
2990 m
->valid
|= pagebits
;
2991 m
->dirty
|= pagebits
;
2993 vm_object_set_writeable_dirty(m
->object
);
2999 * NOTE: This function does not clear the pmap modified bit.
3000 * Also note that e.g. NFS may use a byte-granular base
3003 * Page must be busied?
3004 * No other requirements.
3007 vm_page_clear_dirty(vm_page_t m
, int base
, int size
)
3009 m
->dirty
&= ~vm_page_bits(base
, size
);
3010 if (base
== 0 && size
== PAGE_SIZE
) {
3011 /*pmap_clear_modify(m);*/
3012 vm_page_flag_clear(m
, PG_NOSYNC
);
3017 * Make the page all-dirty.
3019 * Also make sure the related object and vnode reflect the fact that the
3020 * object may now contain a dirty page.
3022 * Page must be busied?
3023 * No other requirements.
3026 vm_page_dirty(vm_page_t m
)
3029 int pqtype
= m
->queue
- m
->pc
;
3031 KASSERT(pqtype
!= PQ_CACHE
&& pqtype
!= PQ_FREE
,
3032 ("vm_page_dirty: page in free/cache queue!"));
3033 if (m
->dirty
!= VM_PAGE_BITS_ALL
) {
3034 m
->dirty
= VM_PAGE_BITS_ALL
;
3036 vm_object_set_writeable_dirty(m
->object
);
3041 * Invalidates DEV_BSIZE'd chunks within a page. Both the
3042 * valid and dirty bits for the effected areas are cleared.
3044 * Page must be busied?
3046 * No other requirements.
3049 vm_page_set_invalid(vm_page_t m
, int base
, int size
)
3053 bits
= vm_page_bits(base
, size
);
3056 m
->object
->generation
++;
3060 * The kernel assumes that the invalid portions of a page contain
3061 * garbage, but such pages can be mapped into memory by user code.
3062 * When this occurs, we must zero out the non-valid portions of the
3063 * page so user code sees what it expects.
3065 * Pages are most often semi-valid when the end of a file is mapped
3066 * into memory and the file's size is not page aligned.
3068 * Page must be busied?
3069 * No other requirements.
3072 vm_page_zero_invalid(vm_page_t m
, boolean_t setvalid
)
3078 * Scan the valid bits looking for invalid sections that
3079 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the
3080 * valid bit may be set ) have already been zerod by
3081 * vm_page_set_validclean().
3083 for (b
= i
= 0; i
<= PAGE_SIZE
/ DEV_BSIZE
; ++i
) {
3084 if (i
== (PAGE_SIZE
/ DEV_BSIZE
) ||
3085 (m
->valid
& (1 << i
))
3088 pmap_zero_page_area(
3091 (i
- b
) << DEV_BSHIFT
3099 * setvalid is TRUE when we can safely set the zero'd areas
3100 * as being valid. We can do this if there are no cache consistency
3101 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS.
3104 m
->valid
= VM_PAGE_BITS_ALL
;
3108 * Is a (partial) page valid? Note that the case where size == 0
3109 * will return FALSE in the degenerate case where the page is entirely
3110 * invalid, and TRUE otherwise.
3113 * No other requirements.
3116 vm_page_is_valid(vm_page_t m
, int base
, int size
)
3118 int bits
= vm_page_bits(base
, size
);
3120 if (m
->valid
&& ((m
->valid
& bits
) == bits
))
3127 * update dirty bits from pmap/mmu. May not block.
3129 * Caller must hold the page busy
3132 vm_page_test_dirty(vm_page_t m
)
3134 if ((m
->dirty
!= VM_PAGE_BITS_ALL
) && pmap_is_modified(m
)) {
3140 * Register an action, associating it with its vm_page
3143 vm_page_register_action(vm_page_action_t action
, vm_page_event_t event
)
3145 struct vm_page_action_list
*list
;
3148 hv
= (int)((intptr_t)action
->m
>> 8) & VMACTION_HMASK
;
3149 list
= &action_list
[hv
];
3151 lwkt_gettoken(&vm_token
);
3152 vm_page_flag_set(action
->m
, PG_ACTIONLIST
);
3153 action
->event
= event
;
3154 LIST_INSERT_HEAD(list
, action
, entry
);
3155 lwkt_reltoken(&vm_token
);
3159 * Unregister an action, disassociating it from its related vm_page
3162 vm_page_unregister_action(vm_page_action_t action
)
3164 struct vm_page_action_list
*list
;
3167 lwkt_gettoken(&vm_token
);
3168 if (action
->event
!= VMEVENT_NONE
) {
3169 action
->event
= VMEVENT_NONE
;
3170 LIST_REMOVE(action
, entry
);
3172 hv
= (int)((intptr_t)action
->m
>> 8) & VMACTION_HMASK
;
3173 list
= &action_list
[hv
];
3174 if (LIST_EMPTY(list
))
3175 vm_page_flag_clear(action
->m
, PG_ACTIONLIST
);
3177 lwkt_reltoken(&vm_token
);
3181 * Issue an event on a VM page. Corresponding action structures are
3182 * removed from the page's list and called.
3184 * If the vm_page has no more pending action events we clear its
3185 * PG_ACTIONLIST flag.
3188 vm_page_event_internal(vm_page_t m
, vm_page_event_t event
)
3190 struct vm_page_action_list
*list
;
3191 struct vm_page_action
*scan
;
3192 struct vm_page_action
*next
;
3196 hv
= (int)((intptr_t)m
>> 8) & VMACTION_HMASK
;
3197 list
= &action_list
[hv
];
3200 lwkt_gettoken(&vm_token
);
3201 LIST_FOREACH_MUTABLE(scan
, list
, entry
, next
) {
3203 if (scan
->event
== event
) {
3204 scan
->event
= VMEVENT_NONE
;
3205 LIST_REMOVE(scan
, entry
);
3206 scan
->func(m
, scan
);
3214 vm_page_flag_clear(m
, PG_ACTIONLIST
);
3215 lwkt_reltoken(&vm_token
);
3218 #include "opt_ddb.h"
3220 #include <sys/kernel.h>
3222 #include <ddb/ddb.h>
3224 DB_SHOW_COMMAND(page
, vm_page_print_page_info
)
3226 db_printf("vmstats.v_free_count: %d\n", vmstats
.v_free_count
);
3227 db_printf("vmstats.v_cache_count: %d\n", vmstats
.v_cache_count
);
3228 db_printf("vmstats.v_inactive_count: %d\n", vmstats
.v_inactive_count
);
3229 db_printf("vmstats.v_active_count: %d\n", vmstats
.v_active_count
);
3230 db_printf("vmstats.v_wire_count: %d\n", vmstats
.v_wire_count
);
3231 db_printf("vmstats.v_free_reserved: %d\n", vmstats
.v_free_reserved
);
3232 db_printf("vmstats.v_free_min: %d\n", vmstats
.v_free_min
);
3233 db_printf("vmstats.v_free_target: %d\n", vmstats
.v_free_target
);
3234 db_printf("vmstats.v_cache_min: %d\n", vmstats
.v_cache_min
);
3235 db_printf("vmstats.v_inactive_target: %d\n", vmstats
.v_inactive_target
);
3238 DB_SHOW_COMMAND(pageq
, vm_page_print_pageq_info
)
3241 db_printf("PQ_FREE:");
3242 for(i
=0;i
<PQ_L2_SIZE
;i
++) {
3243 db_printf(" %d", vm_page_queues
[PQ_FREE
+ i
].lcnt
);
3247 db_printf("PQ_CACHE:");
3248 for(i
=0;i
<PQ_L2_SIZE
;i
++) {
3249 db_printf(" %d", vm_page_queues
[PQ_CACHE
+ i
].lcnt
);
3253 db_printf("PQ_ACTIVE:");
3254 for(i
=0;i
<PQ_L2_SIZE
;i
++) {
3255 db_printf(" %d", vm_page_queues
[PQ_ACTIVE
+ i
].lcnt
);
3259 db_printf("PQ_INACTIVE:");
3260 for(i
=0;i
<PQ_L2_SIZE
;i
++) {
3261 db_printf(" %d", vm_page_queues
[PQ_INACTIVE
+ i
].lcnt
);