This is a major revamping of the pageout and low-memory handling code.
[dragonfly.git] / sys / vm / vm_page.c
CommitLineData
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1/*
2 * Copyright (c) 1991 Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91
37 * $FreeBSD: src/sys/vm/vm_page.c,v 1.147.2.18 2002/03/10 05:03:19 alc Exp $
cfd17028 38 * $DragonFly: src/sys/vm/vm_page.c,v 1.40 2008/08/25 17:01:42 dillon Exp $
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39 */
40
41/*
42 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
43 * All rights reserved.
44 *
45 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
46 *
47 * Permission to use, copy, modify and distribute this software and
48 * its documentation is hereby granted, provided that both the copyright
49 * notice and this permission notice appear in all copies of the
50 * software, derivative works or modified versions, and any portions
51 * thereof, and that both notices appear in supporting documentation.
52 *
53 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
54 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
55 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
56 *
57 * Carnegie Mellon requests users of this software to return to
58 *
59 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
60 * School of Computer Science
61 * Carnegie Mellon University
62 * Pittsburgh PA 15213-3890
63 *
64 * any improvements or extensions that they make and grant Carnegie the
65 * rights to redistribute these changes.
66 */
984263bc 67/*
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68 * Resident memory management module. The module manipulates 'VM pages'.
69 * A VM page is the core building block for memory management.
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70 */
71
72#include <sys/param.h>
73#include <sys/systm.h>
74#include <sys/malloc.h>
75#include <sys/proc.h>
76#include <sys/vmmeter.h>
77#include <sys/vnode.h>
78
79#include <vm/vm.h>
80#include <vm/vm_param.h>
81#include <sys/lock.h>
82#include <vm/vm_kern.h>
83#include <vm/pmap.h>
84#include <vm/vm_map.h>
85#include <vm/vm_object.h>
86#include <vm/vm_page.h>
87#include <vm/vm_pageout.h>
88#include <vm/vm_pager.h>
89#include <vm/vm_extern.h>
12e4aaff 90#include <vm/vm_page2.h>
984263bc 91
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92static void vm_page_queue_init(void);
93static void vm_page_free_wakeup(void);
94static vm_page_t vm_page_select_cache(vm_object_t, vm_pindex_t);
74232d8e 95static vm_page_t _vm_page_list_find2(int basequeue, int index);
984263bc 96
de71fd3f 97struct vpgqueues vm_page_queues[PQ_COUNT]; /* Array of tailq lists */
984263bc 98
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99#define ASSERT_IN_CRIT_SECTION() KKASSERT(crit_test(curthread));
100
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101RB_GENERATE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare,
102 vm_pindex_t, pindex);
103
984263bc 104static void
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105vm_page_queue_init(void)
106{
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107 int i;
108
de71fd3f 109 for (i = 0; i < PQ_L2_SIZE; i++)
12e4aaff 110 vm_page_queues[PQ_FREE+i].cnt = &vmstats.v_free_count;
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111 for (i = 0; i < PQ_L2_SIZE; i++)
112 vm_page_queues[PQ_CACHE+i].cnt = &vmstats.v_cache_count;
984263bc 113
de71fd3f 114 vm_page_queues[PQ_INACTIVE].cnt = &vmstats.v_inactive_count;
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115 vm_page_queues[PQ_ACTIVE].cnt = &vmstats.v_active_count;
116 vm_page_queues[PQ_HOLD].cnt = &vmstats.v_active_count;
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117 /* PQ_NONE has no queue */
118
119 for (i = 0; i < PQ_COUNT; i++)
984263bc 120 TAILQ_INIT(&vm_page_queues[i].pl);
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121}
122
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123/*
124 * note: place in initialized data section? Is this necessary?
125 */
984263bc 126long first_page = 0;
de71fd3f 127int vm_page_array_size = 0;
984263bc 128int vm_page_zero_count = 0;
de71fd3f 129vm_page_t vm_page_array = 0;
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130
131/*
de71fd3f 132 * (low level boot)
984263bc 133 *
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134 * Sets the page size, perhaps based upon the memory size.
135 * Must be called before any use of page-size dependent functions.
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136 */
137void
138vm_set_page_size(void)
139{
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140 if (vmstats.v_page_size == 0)
141 vmstats.v_page_size = PAGE_SIZE;
142 if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0)
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143 panic("vm_set_page_size: page size not a power of two");
144}
145
146/*
de71fd3f 147 * (low level boot)
984263bc 148 *
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149 * Add a new page to the freelist for use by the system. New pages
150 * are added to both the head and tail of the associated free page
151 * queue in a bottom-up fashion, so both zero'd and non-zero'd page
152 * requests pull 'recent' adds (higher physical addresses) first.
161399b3 153 *
654a39f0 154 * Must be called in a critical section.
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155 */
156vm_page_t
6ef943a3 157vm_add_new_page(vm_paddr_t pa)
984263bc 158{
161399b3 159 struct vpgqueues *vpq;
de71fd3f 160 vm_page_t m;
984263bc 161
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162 ++vmstats.v_page_count;
163 ++vmstats.v_free_count;
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164 m = PHYS_TO_VM_PAGE(pa);
165 m->phys_addr = pa;
166 m->flags = 0;
167 m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK;
168 m->queue = m->pc + PQ_FREE;
26bcc0c0 169 KKASSERT(m->dirty == 0);
de71fd3f 170
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171 vpq = &vm_page_queues[m->queue];
172 if (vpq->flipflop)
173 TAILQ_INSERT_TAIL(&vpq->pl, m, pageq);
174 else
175 TAILQ_INSERT_HEAD(&vpq->pl, m, pageq);
176 vpq->flipflop = 1 - vpq->flipflop;
de71fd3f 177
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178 vm_page_queues[m->queue].lcnt++;
179 return (m);
180}
181
182/*
de71fd3f 183 * (low level boot)
984263bc 184 *
de71fd3f 185 * Initializes the resident memory module.
984263bc 186 *
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187 * Allocates memory for the page cells, and for the object/offset-to-page
188 * hash table headers. Each page cell is initialized and placed on the
189 * free list.
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190 *
191 * starta/enda represents the range of physical memory addresses available
192 * for use (skipping memory already used by the kernel), subject to
193 * phys_avail[]. Note that phys_avail[] has already mapped out memory
194 * already in use by the kernel.
984263bc 195 */
984263bc 196vm_offset_t
26bcc0c0 197vm_page_startup(vm_offset_t vaddr)
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198{
199 vm_offset_t mapped;
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200 vm_size_t npages;
201 vm_paddr_t page_range;
202 vm_paddr_t new_end;
984263bc 203 int i;
6ef943a3 204 vm_paddr_t pa;
984263bc 205 int nblocks;
6ef943a3 206 vm_paddr_t last_pa;
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207 vm_paddr_t end;
208 vm_paddr_t biggestone, biggestsize;
6ef943a3 209 vm_paddr_t total;
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210
211 total = 0;
212 biggestsize = 0;
213 biggestone = 0;
214 nblocks = 0;
215 vaddr = round_page(vaddr);
216
217 for (i = 0; phys_avail[i + 1]; i += 2) {
218 phys_avail[i] = round_page(phys_avail[i]);
219 phys_avail[i + 1] = trunc_page(phys_avail[i + 1]);
220 }
221
222 for (i = 0; phys_avail[i + 1]; i += 2) {
6ef943a3 223 vm_paddr_t size = phys_avail[i + 1] - phys_avail[i];
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224
225 if (size > biggestsize) {
226 biggestone = i;
227 biggestsize = size;
228 }
229 ++nblocks;
230 total += size;
231 }
232
233 end = phys_avail[biggestone+1];
1f804340 234 end = trunc_page(end);
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235
236 /*
237 * Initialize the queue headers for the free queue, the active queue
238 * and the inactive queue.
239 */
240
241 vm_page_queue_init();
242
243 /*
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244 * Compute the number of pages of memory that will be available for
245 * use (taking into account the overhead of a page structure per
246 * page).
247 */
984263bc 248 first_page = phys_avail[0] / PAGE_SIZE;
984263bc 249 page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page;
1f804340 250 npages = (total - (page_range * sizeof(struct vm_page))) / PAGE_SIZE;
de71fd3f 251
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252 /*
253 * Initialize the mem entry structures now, and put them in the free
254 * queue.
255 */
256 vm_page_array = (vm_page_t) vaddr;
257 mapped = vaddr;
258
259 /*
260 * Validate these addresses.
261 */
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262 new_end = trunc_page(end - page_range * sizeof(struct vm_page));
263 mapped = pmap_map(mapped, new_end, end,
264 VM_PROT_READ | VM_PROT_WRITE);
265
266 /*
267 * Clear all of the page structures
268 */
269 bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page));
270 vm_page_array_size = page_range;
271
272 /*
161399b3 273 * Construct the free queue(s) in ascending order (by physical
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274 * address) so that the first 16MB of physical memory is allocated
275 * last rather than first. On large-memory machines, this avoids
276 * the exhaustion of low physical memory before isa_dmainit has run.
277 */
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278 vmstats.v_page_count = 0;
279 vmstats.v_free_count = 0;
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280 for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) {
281 pa = phys_avail[i];
282 if (i == biggestone)
283 last_pa = new_end;
284 else
285 last_pa = phys_avail[i + 1];
286 while (pa < last_pa && npages-- > 0) {
287 vm_add_new_page(pa);
288 pa += PAGE_SIZE;
289 }
290 }
291 return (mapped);
292}
293
294/*
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295 * Scan comparison function for Red-Black tree scans. An inclusive
296 * (start,end) is expected. Other fields are not used.
984263bc 297 */
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298int
299rb_vm_page_scancmp(struct vm_page *p, void *data)
984263bc 300{
1f804340 301 struct rb_vm_page_scan_info *info = data;
984263bc 302
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303 if (p->pindex < info->start_pindex)
304 return(-1);
305 if (p->pindex > info->end_pindex)
306 return(1);
307 return(0);
308}
309
310int
311rb_vm_page_compare(struct vm_page *p1, struct vm_page *p2)
312{
313 if (p1->pindex < p2->pindex)
314 return(-1);
315 if (p1->pindex > p2->pindex)
316 return(1);
317 return(0);
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318}
319
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320/*
321 * The opposite of vm_page_hold(). A page can be freed while being held,
322 * which places it on the PQ_HOLD queue. We must call vm_page_free_toq()
323 * in this case to actually free it once the hold count drops to 0.
324 *
325 * This routine must be called at splvm().
326 */
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327void
328vm_page_unhold(vm_page_t mem)
329{
330 --mem->hold_count;
331 KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!"));
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332 if (mem->hold_count == 0 && mem->queue == PQ_HOLD) {
333 vm_page_busy(mem);
984263bc 334 vm_page_free_toq(mem);
97edb3b6 335 }
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336}
337
338/*
de71fd3f 339 * Inserts the given mem entry into the object and object list.
984263bc 340 *
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341 * The pagetables are not updated but will presumably fault the page
342 * in if necessary, or if a kernel page the caller will at some point
343 * enter the page into the kernel's pmap. We are not allowed to block
344 * here so we *can't* do this anyway.
984263bc 345 *
de71fd3f 346 * This routine may not block.
654a39f0 347 * This routine must be called with a critical section held.
984263bc 348 */
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349void
350vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
351{
654a39f0 352 ASSERT_IN_CRIT_SECTION();
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353 if (m->object != NULL)
354 panic("vm_page_insert: already inserted");
355
356 /*
357 * Record the object/offset pair in this page
358 */
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359 m->object = object;
360 m->pindex = pindex;
361
362 /*
1f804340 363 * Insert it into the object.
984263bc 364 */
1f804340 365 vm_page_rb_tree_RB_INSERT(&object->rb_memq, m);
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366 object->generation++;
367
368 /*
369 * show that the object has one more resident page.
370 */
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371 object->resident_page_count++;
372
373 /*
374 * Since we are inserting a new and possibly dirty page,
375 * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags.
376 */
17cde63e 377 if ((m->valid & m->dirty) || (m->flags & PG_WRITEABLE))
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378 vm_object_set_writeable_dirty(object);
379}
380
381/*
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382 * Removes the given vm_page_t from the global (object,index) hash table
383 * and from the object's memq.
984263bc 384 *
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385 * The underlying pmap entry (if any) is NOT removed here.
386 * This routine may not block.
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387 *
388 * The page must be BUSY and will remain BUSY on return. No spl needs to be
389 * held on call to this routine.
390 *
391 * note: FreeBSD side effect was to unbusy the page on return. We leave
392 * it busy.
984263bc 393 */
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394void
395vm_page_remove(vm_page_t m)
396{
397 vm_object_t object;
398
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399 crit_enter();
400 if (m->object == NULL) {
401 crit_exit();
984263bc 402 return;
654a39f0 403 }
984263bc 404
de71fd3f 405 if ((m->flags & PG_BUSY) == 0)
984263bc 406 panic("vm_page_remove: page not busy");
984263bc 407
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408 object = m->object;
409
410 /*
1f804340 411 * Remove the page from the object and update the object.
984263bc 412 */
1f804340 413 vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m);
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414 object->resident_page_count--;
415 object->generation++;
984263bc 416 m->object = NULL;
1f804340 417
9765affa 418 crit_exit();
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419}
420
421/*
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422 * Locate and return the page at (object, pindex), or NULL if the
423 * page could not be found.
424 *
425 * This routine will operate properly without spl protection, but
426 * the returned page could be in flux if it is busy. Because an
427 * interrupt can race a caller's busy check (unbusying and freeing the
428 * page we return before the caller is able to check the busy bit),
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429 * the caller should generally call this routine with a critical
430 * section held.
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431 *
432 * Callers may call this routine without spl protection if they know
433 * 'for sure' that the page will not be ripped out from under them
434 * by an interrupt.
984263bc 435 */
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436vm_page_t
437vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
438{
439 vm_page_t m;
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440
441 /*
442 * Search the hash table for this object/offset pair
443 */
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444 crit_enter();
445 m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex);
446 crit_exit();
447 KKASSERT(m == NULL || (m->object == object && m->pindex == pindex));
448 return(m);
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449}
450
451/*
de71fd3f 452 * vm_page_rename()
984263bc 453 *
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454 * Move the given memory entry from its current object to the specified
455 * target object/offset.
984263bc 456 *
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457 * The object must be locked.
458 * This routine may not block.
984263bc 459 *
de71fd3f 460 * Note: This routine will raise itself to splvm(), the caller need not.
984263bc 461 *
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462 * Note: Swap associated with the page must be invalidated by the move. We
463 * have to do this for several reasons: (1) we aren't freeing the
464 * page, (2) we are dirtying the page, (3) the VM system is probably
465 * moving the page from object A to B, and will then later move
466 * the backing store from A to B and we can't have a conflict.
984263bc 467 *
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468 * Note: We *always* dirty the page. It is necessary both for the
469 * fact that we moved it, and because we may be invalidating
470 * swap. If the page is on the cache, we have to deactivate it
471 * or vm_page_dirty() will panic. Dirty pages are not allowed
472 * on the cache.
984263bc 473 */
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474void
475vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
476{
9765affa 477 crit_enter();
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478 vm_page_remove(m);
479 vm_page_insert(m, new_object, new_pindex);
480 if (m->queue - m->pc == PQ_CACHE)
481 vm_page_deactivate(m);
482 vm_page_dirty(m);
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483 vm_page_wakeup(m);
484 crit_exit();
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485}
486
487/*
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488 * vm_page_unqueue() without any wakeup. This routine is used when a page
489 * is being moved between queues or otherwise is to remain BUSYied by the
490 * caller.
984263bc 491 *
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492 * This routine must be called at splhigh().
493 * This routine may not block.
984263bc 494 */
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495void
496vm_page_unqueue_nowakeup(vm_page_t m)
497{
498 int queue = m->queue;
499 struct vpgqueues *pq;
de71fd3f 500
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501 if (queue != PQ_NONE) {
502 pq = &vm_page_queues[queue];
503 m->queue = PQ_NONE;
504 TAILQ_REMOVE(&pq->pl, m, pageq);
505 (*pq->cnt)--;
506 pq->lcnt--;
507 }
508}
509
510/*
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511 * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon
512 * if necessary.
984263bc 513 *
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514 * This routine must be called at splhigh().
515 * This routine may not block.
984263bc 516 */
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517void
518vm_page_unqueue(vm_page_t m)
519{
520 int queue = m->queue;
521 struct vpgqueues *pq;
de71fd3f 522
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523 if (queue != PQ_NONE) {
524 m->queue = PQ_NONE;
525 pq = &vm_page_queues[queue];
526 TAILQ_REMOVE(&pq->pl, m, pageq);
527 (*pq->cnt)--;
528 pq->lcnt--;
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529 if ((queue - m->pc) == PQ_CACHE || (queue - m->pc) == PQ_FREE)
530 pagedaemon_wakeup();
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531 }
532}
533
984263bc 534/*
de71fd3f 535 * vm_page_list_find()
984263bc 536 *
de71fd3f 537 * Find a page on the specified queue with color optimization.
984263bc 538 *
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539 * The page coloring optimization attempts to locate a page that does
540 * not overload other nearby pages in the object in the cpu's L1 or L2
541 * caches. We need this optimization because cpu caches tend to be
542 * physical caches, while object spaces tend to be virtual.
984263bc 543 *
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544 * This routine must be called at splvm().
545 * This routine may not block.
984263bc 546 *
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547 * Note that this routine is carefully inlined. A non-inlined version
548 * is available for outside callers but the only critical path is
549 * from within this source file.
984263bc 550 */
74232d8e 551static __inline
984263bc 552vm_page_t
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553_vm_page_list_find(int basequeue, int index, boolean_t prefer_zero)
554{
555 vm_page_t m;
556
557 if (prefer_zero)
558 m = TAILQ_LAST(&vm_page_queues[basequeue+index].pl, pglist);
559 else
560 m = TAILQ_FIRST(&vm_page_queues[basequeue+index].pl);
561 if (m == NULL)
562 m = _vm_page_list_find2(basequeue, index);
563 return(m);
564}
565
566static vm_page_t
567_vm_page_list_find2(int basequeue, int index)
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568{
569 int i;
570 vm_page_t m = NULL;
571 struct vpgqueues *pq;
572
573 pq = &vm_page_queues[basequeue];
574
575 /*
576 * Note that for the first loop, index+i and index-i wind up at the
577 * same place. Even though this is not totally optimal, we've already
578 * blown it by missing the cache case so we do not care.
579 */
580
581 for(i = PQ_L2_SIZE / 2; i > 0; --i) {
582 if ((m = TAILQ_FIRST(&pq[(index + i) & PQ_L2_MASK].pl)) != NULL)
583 break;
584
585 if ((m = TAILQ_FIRST(&pq[(index - i) & PQ_L2_MASK].pl)) != NULL)
586 break;
587 }
588 return(m);
589}
590
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591vm_page_t
592vm_page_list_find(int basequeue, int index, boolean_t prefer_zero)
593{
594 return(_vm_page_list_find(basequeue, index, prefer_zero));
595}
596
984263bc 597/*
de71fd3f
MD
598 * Find a page on the cache queue with color optimization. As pages
599 * might be found, but not applicable, they are deactivated. This
600 * keeps us from using potentially busy cached pages.
984263bc 601 *
654a39f0 602 * This routine must be called with a critical section held.
de71fd3f 603 * This routine may not block.
984263bc
MD
604 */
605vm_page_t
606vm_page_select_cache(vm_object_t object, vm_pindex_t pindex)
607{
608 vm_page_t m;
609
610 while (TRUE) {
659c6a07 611 m = _vm_page_list_find(
984263bc
MD
612 PQ_CACHE,
613 (pindex + object->pg_color) & PQ_L2_MASK,
614 FALSE
615 );
616 if (m && ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy ||
617 m->hold_count || m->wire_count)) {
618 vm_page_deactivate(m);
619 continue;
620 }
621 return m;
622 }
de71fd3f 623 /* not reached */
984263bc
MD
624}
625
626/*
de71fd3f
MD
627 * Find a free or zero page, with specified preference. We attempt to
628 * inline the nominal case and fall back to _vm_page_select_free()
629 * otherwise.
984263bc 630 *
654a39f0 631 * This routine must be called with a critical section held.
de71fd3f 632 * This routine may not block.
984263bc 633 */
984263bc
MD
634static __inline vm_page_t
635vm_page_select_free(vm_object_t object, vm_pindex_t pindex, boolean_t prefer_zero)
636{
637 vm_page_t m;
638
659c6a07 639 m = _vm_page_list_find(
984263bc
MD
640 PQ_FREE,
641 (pindex + object->pg_color) & PQ_L2_MASK,
642 prefer_zero
643 );
644 return(m);
645}
646
647/*
de71fd3f 648 * vm_page_alloc()
984263bc 649 *
de71fd3f
MD
650 * Allocate and return a memory cell associated with this VM object/offset
651 * pair.
984263bc
MD
652 *
653 * page_req classes:
de71fd3f 654 *
dc1fd4b3
MD
655 * VM_ALLOC_NORMAL allow use of cache pages, nominal free drain
656 * VM_ALLOC_SYSTEM greater free drain
657 * VM_ALLOC_INTERRUPT allow free list to be completely drained
658 * VM_ALLOC_ZERO advisory request for pre-zero'd page
984263bc 659 *
de71fd3f
MD
660 * The object must be locked.
661 * This routine may not block.
9765affa 662 * The returned page will be marked PG_BUSY
984263bc 663 *
de71fd3f
MD
664 * Additional special handling is required when called from an interrupt
665 * (VM_ALLOC_INTERRUPT). We are not allowed to mess with the page cache
666 * in this case.
984263bc 667 */
984263bc
MD
668vm_page_t
669vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int page_req)
670{
671 vm_page_t m = NULL;
984263bc 672
cfd17028 673 KKASSERT(object != NULL);
984263bc
MD
674 KASSERT(!vm_page_lookup(object, pindex),
675 ("vm_page_alloc: page already allocated"));
dc1fd4b3
MD
676 KKASSERT(page_req &
677 (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
984263bc
MD
678
679 /*
4ecf7cc9
MD
680 * Certain system threads (pageout daemon, buf_daemon's) are
681 * allowed to eat deeper into the free page list.
984263bc 682 */
4ecf7cc9 683 if (curthread->td_flags & TDF_SYSTHREAD)
dc1fd4b3 684 page_req |= VM_ALLOC_SYSTEM;
984263bc 685
9765affa 686 crit_enter();
984263bc 687loop:
dc1fd4b3
MD
688 if (vmstats.v_free_count > vmstats.v_free_reserved ||
689 ((page_req & VM_ALLOC_INTERRUPT) && vmstats.v_free_count > 0) ||
690 ((page_req & VM_ALLOC_SYSTEM) && vmstats.v_cache_count == 0 &&
691 vmstats.v_free_count > vmstats.v_interrupt_free_min)
692 ) {
984263bc 693 /*
dc1fd4b3 694 * The free queue has sufficient free pages to take one out.
984263bc 695 */
dc1fd4b3 696 if (page_req & VM_ALLOC_ZERO)
984263bc
MD
697 m = vm_page_select_free(object, pindex, TRUE);
698 else
699 m = vm_page_select_free(object, pindex, FALSE);
dc1fd4b3 700 } else if (page_req & VM_ALLOC_NORMAL) {
984263bc 701 /*
dc1fd4b3
MD
702 * Allocatable from the cache (non-interrupt only). On
703 * success, we must free the page and try again, thus
704 * ensuring that vmstats.v_*_free_min counters are replenished.
984263bc 705 */
dc1fd4b3
MD
706#ifdef INVARIANTS
707 if (curthread->td_preempted) {
086c1d7e 708 kprintf("vm_page_alloc(): warning, attempt to allocate"
dc1fd4b3
MD
709 " cache page from preempting interrupt\n");
710 m = NULL;
711 } else {
712 m = vm_page_select_cache(object, pindex);
713 }
714#else
715 m = vm_page_select_cache(object, pindex);
716#endif
984263bc 717 /*
9765affa 718 * On success move the page into the free queue and loop.
984263bc 719 */
dc1fd4b3
MD
720 if (m != NULL) {
721 KASSERT(m->dirty == 0,
722 ("Found dirty cache page %p", m));
723 vm_page_busy(m);
724 vm_page_protect(m, VM_PROT_NONE);
725 vm_page_free(m);
726 goto loop;
727 }
728
729 /*
730 * On failure return NULL
731 */
9765affa 732 crit_exit();
984263bc 733#if defined(DIAGNOSTIC)
dc1fd4b3 734 if (vmstats.v_cache_count > 0)
086c1d7e 735 kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats.v_cache_count);
984263bc 736#endif
dc1fd4b3
MD
737 vm_pageout_deficit++;
738 pagedaemon_wakeup();
739 return (NULL);
984263bc
MD
740 } else {
741 /*
dc1fd4b3 742 * No pages available, wakeup the pageout daemon and give up.
984263bc 743 */
9765affa 744 crit_exit();
984263bc
MD
745 vm_pageout_deficit++;
746 pagedaemon_wakeup();
747 return (NULL);
748 }
749
750 /*
9765affa
MD
751 * Good page found. The page has not yet been busied. We are in
752 * a critical section.
984263bc 753 */
dc1fd4b3 754 KASSERT(m != NULL, ("vm_page_alloc(): missing page on free queue\n"));
26bcc0c0
MD
755 KASSERT(m->dirty == 0,
756 ("vm_page_alloc: free/cache page %p was dirty", m));
984263bc
MD
757
758 /*
759 * Remove from free queue
760 */
984263bc
MD
761 vm_page_unqueue_nowakeup(m);
762
763 /*
9765affa
MD
764 * Initialize structure. Only the PG_ZERO flag is inherited. Set
765 * the page PG_BUSY
984263bc 766 */
984263bc
MD
767 if (m->flags & PG_ZERO) {
768 vm_page_zero_count--;
769 m->flags = PG_ZERO | PG_BUSY;
770 } else {
771 m->flags = PG_BUSY;
772 }
773 m->wire_count = 0;
774 m->hold_count = 0;
775 m->act_count = 0;
776 m->busy = 0;
777 m->valid = 0;
984263bc
MD
778
779 /*
9765affa 780 * vm_page_insert() is safe prior to the crit_exit(). Note also that
984263bc
MD
781 * inserting a page here does not insert it into the pmap (which
782 * could cause us to block allocating memory). We cannot block
783 * anywhere.
784 */
984263bc
MD
785 vm_page_insert(m, object, pindex);
786
787 /*
788 * Don't wakeup too often - wakeup the pageout daemon when
789 * we would be nearly out of memory.
790 */
20479584 791 pagedaemon_wakeup();
984263bc 792
9765affa
MD
793 crit_exit();
794
795 /*
796 * A PG_BUSY page is returned.
797 */
984263bc
MD
798 return (m);
799}
800
801/*
de71fd3f
MD
802 * Block until free pages are available for allocation, called in various
803 * places before memory allocations.
984263bc 804 */
984263bc 805void
4ecf7cc9 806vm_wait(int timo)
984263bc 807{
cdd46d2e 808 crit_enter();
bc6dffab 809 if (curthread == pagethread) {
984263bc 810 vm_pageout_pages_needed = 1;
4ecf7cc9 811 tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo);
984263bc 812 } else {
20479584 813 if (vm_pages_needed == 0) {
984263bc
MD
814 vm_pages_needed = 1;
815 wakeup(&vm_pages_needed);
816 }
4ecf7cc9 817 tsleep(&vmstats.v_free_count, 0, "vmwait", timo);
984263bc 818 }
cdd46d2e 819 crit_exit();
984263bc
MD
820}
821
822/*
de71fd3f
MD
823 * Block until free pages are available for allocation
824 *
825 * Called only in vm_fault so that processes page faulting can be
826 * easily tracked.
984263bc 827 */
984263bc
MD
828void
829vm_waitpfault(void)
830{
cdd46d2e 831 crit_enter();
20479584 832 if (vm_pages_needed == 0) {
984263bc
MD
833 vm_pages_needed = 1;
834 wakeup(&vm_pages_needed);
835 }
377d4740 836 tsleep(&vmstats.v_free_count, 0, "pfault", 0);
cdd46d2e 837 crit_exit();
984263bc
MD
838}
839
840/*
de71fd3f
MD
841 * Put the specified page on the active list (if appropriate). Ensure
842 * that act_count is at least ACT_INIT but do not otherwise mess with it.
984263bc 843 *
de71fd3f
MD
844 * The page queues must be locked.
845 * This routine may not block.
984263bc
MD
846 */
847void
848vm_page_activate(vm_page_t m)
849{
9765affa 850 crit_enter();
984263bc
MD
851 if (m->queue != PQ_ACTIVE) {
852 if ((m->queue - m->pc) == PQ_CACHE)
12e4aaff 853 mycpu->gd_cnt.v_reactivated++;
984263bc
MD
854
855 vm_page_unqueue(m);
856
857 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
858 m->queue = PQ_ACTIVE;
859 vm_page_queues[PQ_ACTIVE].lcnt++;
de71fd3f
MD
860 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl,
861 m, pageq);
984263bc
MD
862 if (m->act_count < ACT_INIT)
863 m->act_count = ACT_INIT;
12e4aaff 864 vmstats.v_active_count++;
984263bc
MD
865 }
866 } else {
867 if (m->act_count < ACT_INIT)
868 m->act_count = ACT_INIT;
869 }
9765affa 870 crit_exit();
984263bc
MD
871}
872
873/*
de71fd3f
MD
874 * Helper routine for vm_page_free_toq() and vm_page_cache(). This
875 * routine is called when a page has been added to the cache or free
876 * queues.
984263bc 877 *
de71fd3f
MD
878 * This routine may not block.
879 * This routine must be called at splvm()
984263bc
MD
880 */
881static __inline void
882vm_page_free_wakeup(void)
883{
884 /*
885 * if pageout daemon needs pages, then tell it that there are
886 * some free.
887 */
888 if (vm_pageout_pages_needed &&
de71fd3f
MD
889 vmstats.v_cache_count + vmstats.v_free_count >=
890 vmstats.v_pageout_free_min
891 ) {
984263bc
MD
892 wakeup(&vm_pageout_pages_needed);
893 vm_pageout_pages_needed = 0;
894 }
de71fd3f 895
984263bc
MD
896 /*
897 * wakeup processes that are waiting on memory if we hit a
898 * high water mark. And wakeup scheduler process if we have
899 * lots of memory. this process will swapin processes.
900 */
20479584 901 if (vm_pages_needed && !vm_page_count_min(0)) {
984263bc 902 vm_pages_needed = 0;
12e4aaff 903 wakeup(&vmstats.v_free_count);
984263bc
MD
904 }
905}
906
907/*
908 * vm_page_free_toq:
909 *
9765affa
MD
910 * Returns the given page to the PQ_FREE list, disassociating it with
911 * any VM object.
912 *
913 * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on
914 * return (the page will have been freed). No particular spl is required
915 * on entry.
984263bc 916 *
984263bc
MD
917 * This routine may not block.
918 */
984263bc
MD
919void
920vm_page_free_toq(vm_page_t m)
921{
984263bc 922 struct vpgqueues *pq;
984263bc 923
9765affa 924 crit_enter();
12e4aaff 925 mycpu->gd_cnt.v_tfree++;
984263bc 926
17cde63e
MD
927 KKASSERT((m->flags & PG_MAPPED) == 0);
928
984263bc 929 if (m->busy || ((m->queue - m->pc) == PQ_FREE)) {
086c1d7e 930 kprintf(
984263bc
MD
931 "vm_page_free: pindex(%lu), busy(%d), PG_BUSY(%d), hold(%d)\n",
932 (u_long)m->pindex, m->busy, (m->flags & PG_BUSY) ? 1 : 0,
933 m->hold_count);
934 if ((m->queue - m->pc) == PQ_FREE)
935 panic("vm_page_free: freeing free page");
936 else
937 panic("vm_page_free: freeing busy page");
938 }
939
940 /*
941 * unqueue, then remove page. Note that we cannot destroy
942 * the page here because we do not want to call the pager's
943 * callback routine until after we've put the page on the
944 * appropriate free queue.
945 */
984263bc
MD
946 vm_page_unqueue_nowakeup(m);
947 vm_page_remove(m);
948
949 /*
f2d22ebf
MD
950 * No further management of fictitious pages occurs beyond object
951 * and queue removal.
984263bc 952 */
984263bc 953 if ((m->flags & PG_FICTITIOUS) != 0) {
9765affa
MD
954 vm_page_wakeup(m);
955 crit_exit();
984263bc
MD
956 return;
957 }
958
959 m->valid = 0;
960 vm_page_undirty(m);
961
962 if (m->wire_count != 0) {
963 if (m->wire_count > 1) {
de71fd3f
MD
964 panic(
965 "vm_page_free: invalid wire count (%d), pindex: 0x%lx",
966 m->wire_count, (long)m->pindex);
984263bc 967 }
73c351d1 968 panic("vm_page_free: freeing wired page");
984263bc
MD
969 }
970
971 /*
984263bc
MD
972 * Clear the UNMANAGED flag when freeing an unmanaged page.
973 */
984263bc
MD
974 if (m->flags & PG_UNMANAGED) {
975 m->flags &= ~PG_UNMANAGED;
984263bc
MD
976 }
977
978 if (m->hold_count != 0) {
979 m->flags &= ~PG_ZERO;
980 m->queue = PQ_HOLD;
de71fd3f 981 } else {
984263bc 982 m->queue = PQ_FREE + m->pc;
de71fd3f 983 }
984263bc
MD
984 pq = &vm_page_queues[m->queue];
985 pq->lcnt++;
986 ++(*pq->cnt);
987
988 /*
989 * Put zero'd pages on the end ( where we look for zero'd pages
990 * first ) and non-zerod pages at the head.
991 */
984263bc
MD
992 if (m->flags & PG_ZERO) {
993 TAILQ_INSERT_TAIL(&pq->pl, m, pageq);
994 ++vm_page_zero_count;
995 } else {
996 TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
997 }
9765affa 998 vm_page_wakeup(m);
984263bc 999 vm_page_free_wakeup();
9765affa 1000 crit_exit();
984263bc
MD
1001}
1002
1003/*
de71fd3f
MD
1004 * vm_page_unmanage()
1005 *
1006 * Prevent PV management from being done on the page. The page is
1007 * removed from the paging queues as if it were wired, and as a
1008 * consequence of no longer being managed the pageout daemon will not
1009 * touch it (since there is no way to locate the pte mappings for the
1010 * page). madvise() calls that mess with the pmap will also no longer
1011 * operate on the page.
1012 *
1013 * Beyond that the page is still reasonably 'normal'. Freeing the page
1014 * will clear the flag.
1015 *
1016 * This routine is used by OBJT_PHYS objects - objects using unswappable
1017 * physical memory as backing store rather then swap-backed memory and
1018 * will eventually be extended to support 4MB unmanaged physical
1019 * mappings.
654a39f0
MD
1020 *
1021 * Must be called with a critical section held.
984263bc 1022 */
984263bc
MD
1023void
1024vm_page_unmanage(vm_page_t m)
1025{
654a39f0 1026 ASSERT_IN_CRIT_SECTION();
984263bc
MD
1027 if ((m->flags & PG_UNMANAGED) == 0) {
1028 if (m->wire_count == 0)
1029 vm_page_unqueue(m);
1030 }
1031 vm_page_flag_set(m, PG_UNMANAGED);
984263bc
MD
1032}
1033
1034/*
de71fd3f
MD
1035 * Mark this page as wired down by yet another map, removing it from
1036 * paging queues as necessary.
984263bc 1037 *
de71fd3f
MD
1038 * The page queues must be locked.
1039 * This routine may not block.
984263bc
MD
1040 */
1041void
1042vm_page_wire(vm_page_t m)
1043{
984263bc
MD
1044 /*
1045 * Only bump the wire statistics if the page is not already wired,
1046 * and only unqueue the page if it is on some queue (if it is unmanaged
f2d22ebf
MD
1047 * it is already off the queues). Don't do anything with fictitious
1048 * pages because they are always wired.
984263bc 1049 */
654a39f0 1050 crit_enter();
f2d22ebf
MD
1051 if ((m->flags & PG_FICTITIOUS) == 0) {
1052 if (m->wire_count == 0) {
1053 if ((m->flags & PG_UNMANAGED) == 0)
1054 vm_page_unqueue(m);
1055 vmstats.v_wire_count++;
1056 }
1057 m->wire_count++;
1058 KASSERT(m->wire_count != 0,
17cde63e 1059 ("vm_page_wire: wire_count overflow m=%p", m));
984263bc 1060 }
654a39f0 1061 crit_exit();
984263bc
MD
1062}
1063
1064/*
de71fd3f
MD
1065 * Release one wiring of this page, potentially enabling it to be paged again.
1066 *
1067 * Many pages placed on the inactive queue should actually go
1068 * into the cache, but it is difficult to figure out which. What
1069 * we do instead, if the inactive target is well met, is to put
1070 * clean pages at the head of the inactive queue instead of the tail.
1071 * This will cause them to be moved to the cache more quickly and
1072 * if not actively re-referenced, freed more quickly. If we just
1073 * stick these pages at the end of the inactive queue, heavy filesystem
1074 * meta-data accesses can cause an unnecessary paging load on memory bound
1075 * processes. This optimization causes one-time-use metadata to be
1076 * reused more quickly.
1077 *
1078 * BUT, if we are in a low-memory situation we have no choice but to
1079 * put clean pages on the cache queue.
1080 *
1081 * A number of routines use vm_page_unwire() to guarantee that the page
1082 * will go into either the inactive or active queues, and will NEVER
1083 * be placed in the cache - for example, just after dirtying a page.
1084 * dirty pages in the cache are not allowed.
1085 *
1086 * The page queues must be locked.
1087 * This routine may not block.
984263bc
MD
1088 */
1089void
1090vm_page_unwire(vm_page_t m, int activate)
1091{
654a39f0 1092 crit_enter();
f2d22ebf
MD
1093 if (m->flags & PG_FICTITIOUS) {
1094 /* do nothing */
1095 } else if (m->wire_count <= 0) {
1096 panic("vm_page_unwire: invalid wire count: %d", m->wire_count);
1097 } else {
1098 if (--m->wire_count == 0) {
1099 --vmstats.v_wire_count;
984263bc
MD
1100 if (m->flags & PG_UNMANAGED) {
1101 ;
1102 } else if (activate) {
f2d22ebf
MD
1103 TAILQ_INSERT_TAIL(
1104 &vm_page_queues[PQ_ACTIVE].pl, m, pageq);
984263bc
MD
1105 m->queue = PQ_ACTIVE;
1106 vm_page_queues[PQ_ACTIVE].lcnt++;
12e4aaff 1107 vmstats.v_active_count++;
984263bc
MD
1108 } else {
1109 vm_page_flag_clear(m, PG_WINATCFLS);
f2d22ebf
MD
1110 TAILQ_INSERT_TAIL(
1111 &vm_page_queues[PQ_INACTIVE].pl, m, pageq);
984263bc
MD
1112 m->queue = PQ_INACTIVE;
1113 vm_page_queues[PQ_INACTIVE].lcnt++;
12e4aaff 1114 vmstats.v_inactive_count++;
984263bc
MD
1115 }
1116 }
984263bc 1117 }
654a39f0 1118 crit_exit();
984263bc
MD
1119}
1120
1121
1122/*
1123 * Move the specified page to the inactive queue. If the page has
1124 * any associated swap, the swap is deallocated.
1125 *
1126 * Normally athead is 0 resulting in LRU operation. athead is set
1127 * to 1 if we want this page to be 'as if it were placed in the cache',
1128 * except without unmapping it from the process address space.
1129 *
1130 * This routine may not block.
1131 */
1132static __inline void
1133_vm_page_deactivate(vm_page_t m, int athead)
1134{
984263bc
MD
1135 /*
1136 * Ignore if already inactive.
1137 */
1138 if (m->queue == PQ_INACTIVE)
1139 return;
1140
984263bc
MD
1141 if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
1142 if ((m->queue - m->pc) == PQ_CACHE)
12e4aaff 1143 mycpu->gd_cnt.v_reactivated++;
984263bc
MD
1144 vm_page_flag_clear(m, PG_WINATCFLS);
1145 vm_page_unqueue(m);
1146 if (athead)
1147 TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
1148 else
1149 TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
1150 m->queue = PQ_INACTIVE;
1151 vm_page_queues[PQ_INACTIVE].lcnt++;
12e4aaff 1152 vmstats.v_inactive_count++;
984263bc 1153 }
984263bc
MD
1154}
1155
1156void
1157vm_page_deactivate(vm_page_t m)
1158{
654a39f0 1159 crit_enter();
984263bc 1160 _vm_page_deactivate(m, 0);
654a39f0 1161 crit_exit();
984263bc
MD
1162}
1163
1164/*
1165 * vm_page_try_to_cache:
1166 *
1167 * Returns 0 on failure, 1 on success
1168 */
1169int
1170vm_page_try_to_cache(vm_page_t m)
1171{
654a39f0 1172 crit_enter();
984263bc
MD
1173 if (m->dirty || m->hold_count || m->busy || m->wire_count ||
1174 (m->flags & (PG_BUSY|PG_UNMANAGED))) {
80137ef3 1175 crit_exit();
984263bc
MD
1176 return(0);
1177 }
1178 vm_page_test_dirty(m);
654a39f0
MD
1179 if (m->dirty) {
1180 crit_exit();
984263bc 1181 return(0);
654a39f0 1182 }
984263bc 1183 vm_page_cache(m);
654a39f0 1184 crit_exit();
984263bc
MD
1185 return(1);
1186}
1187
1188/*
de71fd3f
MD
1189 * Attempt to free the page. If we cannot free it, we do nothing.
1190 * 1 is returned on success, 0 on failure.
984263bc 1191 */
984263bc
MD
1192int
1193vm_page_try_to_free(vm_page_t m)
1194{
654a39f0 1195 crit_enter();
984263bc
MD
1196 if (m->dirty || m->hold_count || m->busy || m->wire_count ||
1197 (m->flags & (PG_BUSY|PG_UNMANAGED))) {
654a39f0 1198 crit_exit();
984263bc
MD
1199 return(0);
1200 }
1201 vm_page_test_dirty(m);
654a39f0
MD
1202 if (m->dirty) {
1203 crit_exit();
984263bc 1204 return(0);
654a39f0 1205 }
984263bc
MD
1206 vm_page_busy(m);
1207 vm_page_protect(m, VM_PROT_NONE);
1208 vm_page_free(m);
654a39f0 1209 crit_exit();
984263bc
MD
1210 return(1);
1211}
1212
984263bc
MD
1213/*
1214 * vm_page_cache
1215 *
1216 * Put the specified page onto the page cache queue (if appropriate).
1217 *
1218 * This routine may not block.
1219 */
1220void
1221vm_page_cache(vm_page_t m)
1222{
654a39f0 1223 ASSERT_IN_CRIT_SECTION();
984263bc 1224
2681a43c
HP
1225 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy ||
1226 m->wire_count || m->hold_count) {
086c1d7e 1227 kprintf("vm_page_cache: attempting to cache busy/held page\n");
984263bc
MD
1228 return;
1229 }
c9ec86b3
MD
1230
1231 /*
1232 * Already in the cache (and thus not mapped)
1233 */
17cde63e
MD
1234 if ((m->queue - m->pc) == PQ_CACHE) {
1235 KKASSERT((m->flags & PG_MAPPED) == 0);
984263bc 1236 return;
17cde63e 1237 }
984263bc
MD
1238
1239 /*
c9ec86b3
MD
1240 * Caller is required to test m->dirty, but note that the act of
1241 * removing the page from its maps can cause it to become dirty
1242 * on an SMP system due to another cpu running in usermode.
984263bc 1243 */
c9ec86b3 1244 if (m->dirty) {
984263bc
MD
1245 panic("vm_page_cache: caching a dirty page, pindex: %ld",
1246 (long)m->pindex);
1247 }
c9ec86b3
MD
1248
1249 /*
1250 * Remove all pmaps and indicate that the page is not
17cde63e
MD
1251 * writeable or mapped. Our vm_page_protect() call may
1252 * have blocked (especially w/ VM_PROT_NONE), so recheck
1253 * everything.
c9ec86b3 1254 */
17cde63e 1255 vm_page_busy(m);
c9ec86b3 1256 vm_page_protect(m, VM_PROT_NONE);
17cde63e
MD
1257 vm_page_wakeup(m);
1258 if ((m->flags & (PG_BUSY|PG_UNMANAGED|PG_MAPPED)) || m->busy ||
1259 m->wire_count || m->hold_count) {
1260 /* do nothing */
1261 } else if (m->dirty) {
c9ec86b3
MD
1262 vm_page_deactivate(m);
1263 } else {
1264 vm_page_unqueue_nowakeup(m);
1265 m->queue = PQ_CACHE + m->pc;
1266 vm_page_queues[m->queue].lcnt++;
1267 TAILQ_INSERT_TAIL(&vm_page_queues[m->queue].pl, m, pageq);
1268 vmstats.v_cache_count++;
1269 vm_page_free_wakeup();
1270 }
984263bc
MD
1271}
1272
1273/*
de71fd3f
MD
1274 * vm_page_dontneed()
1275 *
1276 * Cache, deactivate, or do nothing as appropriate. This routine
1277 * is typically used by madvise() MADV_DONTNEED.
1278 *
1279 * Generally speaking we want to move the page into the cache so
1280 * it gets reused quickly. However, this can result in a silly syndrome
1281 * due to the page recycling too quickly. Small objects will not be
1282 * fully cached. On the otherhand, if we move the page to the inactive
1283 * queue we wind up with a problem whereby very large objects
1284 * unnecessarily blow away our inactive and cache queues.
1285 *
1286 * The solution is to move the pages based on a fixed weighting. We
1287 * either leave them alone, deactivate them, or move them to the cache,
1288 * where moving them to the cache has the highest weighting.
1289 * By forcing some pages into other queues we eventually force the
1290 * system to balance the queues, potentially recovering other unrelated
1291 * space from active. The idea is to not force this to happen too
1292 * often.
984263bc 1293 */
984263bc
MD
1294void
1295vm_page_dontneed(vm_page_t m)
1296{
1297 static int dnweight;
1298 int dnw;
1299 int head;
1300
1301 dnw = ++dnweight;
1302
1303 /*
1304 * occassionally leave the page alone
1305 */
654a39f0 1306 crit_enter();
984263bc
MD
1307 if ((dnw & 0x01F0) == 0 ||
1308 m->queue == PQ_INACTIVE ||
1309 m->queue - m->pc == PQ_CACHE
1310 ) {
1311 if (m->act_count >= ACT_INIT)
1312 --m->act_count;
654a39f0 1313 crit_exit();
984263bc
MD
1314 return;
1315 }
1316
1317 if (m->dirty == 0)
1318 vm_page_test_dirty(m);
1319
1320 if (m->dirty || (dnw & 0x0070) == 0) {
1321 /*
1322 * Deactivate the page 3 times out of 32.
1323 */
1324 head = 0;
1325 } else {
1326 /*
1327 * Cache the page 28 times out of every 32. Note that
1328 * the page is deactivated instead of cached, but placed
1329 * at the head of the queue instead of the tail.
1330 */
1331 head = 1;
1332 }
1333 _vm_page_deactivate(m, head);
654a39f0 1334 crit_exit();
984263bc
MD
1335}
1336
1337/*
06ecca5a
MD
1338 * Grab a page, blocking if it is busy and allocating a page if necessary.
1339 * A busy page is returned or NULL.
984263bc 1340 *
dc1fd4b3 1341 * If VM_ALLOC_RETRY is specified VM_ALLOC_NORMAL must also be specified.
06ecca5a 1342 * If VM_ALLOC_RETRY is not specified
dc1fd4b3 1343 *
06ecca5a
MD
1344 * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is
1345 * always returned if we had blocked.
1346 * This routine will never return NULL if VM_ALLOC_RETRY is set.
1347 * This routine may not be called from an interrupt.
1348 * The returned page may not be entirely valid.
1349 *
1350 * This routine may be called from mainline code without spl protection and
1351 * be guarenteed a busied page associated with the object at the specified
1352 * index.
984263bc
MD
1353 */
1354vm_page_t
1355vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
1356{
984263bc 1357 vm_page_t m;
654a39f0 1358 int generation;
984263bc 1359
dc1fd4b3
MD
1360 KKASSERT(allocflags &
1361 (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM));
654a39f0 1362 crit_enter();
984263bc
MD
1363retrylookup:
1364 if ((m = vm_page_lookup(object, pindex)) != NULL) {
1365 if (m->busy || (m->flags & PG_BUSY)) {
1366 generation = object->generation;
1367
984263bc
MD
1368 while ((object->generation == generation) &&
1369 (m->busy || (m->flags & PG_BUSY))) {
1370 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED);
377d4740 1371 tsleep(m, 0, "pgrbwt", 0);
984263bc 1372 if ((allocflags & VM_ALLOC_RETRY) == 0) {
06ecca5a
MD
1373 m = NULL;
1374 goto done;
984263bc
MD
1375 }
1376 }
984263bc
MD
1377 goto retrylookup;
1378 } else {
1379 vm_page_busy(m);
06ecca5a 1380 goto done;
984263bc
MD
1381 }
1382 }
984263bc
MD
1383 m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY);
1384 if (m == NULL) {
4ecf7cc9 1385 vm_wait(0);
984263bc 1386 if ((allocflags & VM_ALLOC_RETRY) == 0)
06ecca5a 1387 goto done;
984263bc
MD
1388 goto retrylookup;
1389 }
06ecca5a 1390done:
654a39f0 1391 crit_exit();
06ecca5a 1392 return(m);
984263bc
MD
1393}
1394
1395/*
1396 * Mapping function for valid bits or for dirty bits in
1397 * a page. May not block.
1398 *
1399 * Inputs are required to range within a page.
1400 */
984263bc
MD
1401__inline int
1402vm_page_bits(int base, int size)
1403{
1404 int first_bit;
1405 int last_bit;
1406
1407 KASSERT(
1408 base + size <= PAGE_SIZE,
1409 ("vm_page_bits: illegal base/size %d/%d", base, size)
1410 );
1411
1412 if (size == 0) /* handle degenerate case */
1413 return(0);
1414
1415 first_bit = base >> DEV_BSHIFT;
1416 last_bit = (base + size - 1) >> DEV_BSHIFT;
1417
1418 return ((2 << last_bit) - (1 << first_bit));
1419}
1420
1421/*
de71fd3f
MD
1422 * Sets portions of a page valid and clean. The arguments are expected
1423 * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
1424 * of any partial chunks touched by the range. The invalid portion of
1425 * such chunks will be zero'd.
984263bc 1426 *
de71fd3f 1427 * This routine may not block.
984263bc 1428 *
de71fd3f 1429 * (base + size) must be less then or equal to PAGE_SIZE.
984263bc
MD
1430 */
1431void
1432vm_page_set_validclean(vm_page_t m, int base, int size)
1433{
1434 int pagebits;
1435 int frag;
1436 int endoff;
1437
1438 if (size == 0) /* handle degenerate case */
1439 return;
1440
1441 /*
1442 * If the base is not DEV_BSIZE aligned and the valid
1443 * bit is clear, we have to zero out a portion of the
1444 * first block.
1445 */
1446
1447 if ((frag = base & ~(DEV_BSIZE - 1)) != base &&
1448 (m->valid & (1 << (base >> DEV_BSHIFT))) == 0
1449 ) {
1450 pmap_zero_page_area(
1451 VM_PAGE_TO_PHYS(m),
1452 frag,
1453 base - frag
1454 );
1455 }
1456
1457 /*
1458 * If the ending offset is not DEV_BSIZE aligned and the
1459 * valid bit is clear, we have to zero out a portion of
1460 * the last block.
1461 */
1462
1463 endoff = base + size;
1464
1465 if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff &&
1466 (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0
1467 ) {
1468 pmap_zero_page_area(
1469 VM_PAGE_TO_PHYS(m),
1470 endoff,
1471 DEV_BSIZE - (endoff & (DEV_BSIZE - 1))
1472 );
1473 }
1474
1475 /*
1476 * Set valid, clear dirty bits. If validating the entire
1477 * page we can safely clear the pmap modify bit. We also
1478 * use this opportunity to clear the PG_NOSYNC flag. If a process
1479 * takes a write fault on a MAP_NOSYNC memory area the flag will
1480 * be set again.
1481 *
1482 * We set valid bits inclusive of any overlap, but we can only
1483 * clear dirty bits for DEV_BSIZE chunks that are fully within
1484 * the range.
1485 */
1486
1487 pagebits = vm_page_bits(base, size);
1488 m->valid |= pagebits;
1489#if 0 /* NOT YET */
1490 if ((frag = base & (DEV_BSIZE - 1)) != 0) {
1491 frag = DEV_BSIZE - frag;
1492 base += frag;
1493 size -= frag;
1494 if (size < 0)
1495 size = 0;
1496 }
1497 pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1));
1498#endif
1499 m->dirty &= ~pagebits;
1500 if (base == 0 && size == PAGE_SIZE) {
1501 pmap_clear_modify(m);
1502 vm_page_flag_clear(m, PG_NOSYNC);
1503 }
1504}
1505
984263bc
MD
1506void
1507vm_page_clear_dirty(vm_page_t m, int base, int size)
1508{
1509 m->dirty &= ~vm_page_bits(base, size);
1510}
1511
1512/*
17cde63e
MD
1513 * Make the page all-dirty.
1514 *
1515 * Also make sure the related object and vnode reflect the fact that the
1516 * object may now contain a dirty page.
1517 */
1518void
1519vm_page_dirty(vm_page_t m)
1520{
1521#ifdef INVARIANTS
1522 int pqtype = m->queue - m->pc;
1523#endif
1524 KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE,
1525 ("vm_page_dirty: page in free/cache queue!"));
1526 if (m->dirty != VM_PAGE_BITS_ALL) {
1527 m->dirty = VM_PAGE_BITS_ALL;
1528 if (m->object)
1529 vm_object_set_writeable_dirty(m->object);
1530 }
1531}
1532
1533/*
de71fd3f
MD
1534 * Invalidates DEV_BSIZE'd chunks within a page. Both the
1535 * valid and dirty bits for the effected areas are cleared.
984263bc 1536 *
de71fd3f 1537 * May not block.
984263bc
MD
1538 */
1539void
1540vm_page_set_invalid(vm_page_t m, int base, int size)
1541{
1542 int bits;
1543
1544 bits = vm_page_bits(base, size);
1545 m->valid &= ~bits;
1546 m->dirty &= ~bits;
1547 m->object->generation++;
1548}
1549
1550/*
de71fd3f
MD
1551 * The kernel assumes that the invalid portions of a page contain
1552 * garbage, but such pages can be mapped into memory by user code.
1553 * When this occurs, we must zero out the non-valid portions of the
1554 * page so user code sees what it expects.
984263bc 1555 *
de71fd3f
MD
1556 * Pages are most often semi-valid when the end of a file is mapped
1557 * into memory and the file's size is not page aligned.
984263bc 1558 */
984263bc
MD
1559void
1560vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
1561{
1562 int b;
1563 int i;
1564
1565 /*
1566 * Scan the valid bits looking for invalid sections that
1567 * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the
1568 * valid bit may be set ) have already been zerod by
1569 * vm_page_set_validclean().
1570 */
984263bc
MD
1571 for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
1572 if (i == (PAGE_SIZE / DEV_BSIZE) ||
1573 (m->valid & (1 << i))
1574 ) {
1575 if (i > b) {
1576 pmap_zero_page_area(
1577 VM_PAGE_TO_PHYS(m),
1578 b << DEV_BSHIFT,
1579 (i - b) << DEV_BSHIFT
1580 );
1581 }
1582 b = i + 1;
1583 }
1584 }
1585
1586 /*
1587 * setvalid is TRUE when we can safely set the zero'd areas
1588 * as being valid. We can do this if there are no cache consistency
1589 * issues. e.g. it is ok to do with UFS, but not ok to do with NFS.
1590 */
984263bc
MD
1591 if (setvalid)
1592 m->valid = VM_PAGE_BITS_ALL;
1593}
1594
1595/*
de71fd3f
MD
1596 * Is a (partial) page valid? Note that the case where size == 0
1597 * will return FALSE in the degenerate case where the page is entirely
1598 * invalid, and TRUE otherwise.
984263bc 1599 *
de71fd3f 1600 * May not block.
984263bc 1601 */
984263bc
MD
1602int
1603vm_page_is_valid(vm_page_t m, int base, int size)
1604{
1605 int bits = vm_page_bits(base, size);
1606
1607 if (m->valid && ((m->valid & bits) == bits))
1608 return 1;
1609 else
1610 return 0;
1611}
1612
1613/*
1614 * update dirty bits from pmap/mmu. May not block.
1615 */
984263bc
MD
1616void
1617vm_page_test_dirty(vm_page_t m)
1618{
1619 if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) {
1620 vm_page_dirty(m);
1621 }
1622}
1623
10192bae
MD
1624/*
1625 * Issue an event on a VM page. Corresponding action structures are
1626 * removed from the page's list and called.
1627 */
1628void
1629vm_page_event_internal(vm_page_t m, vm_page_event_t event)
1630{
1631 struct vm_page_action *scan, *next;
1632
1633 LIST_FOREACH_MUTABLE(scan, &m->action_list, entry, next) {
1634 if (scan->event == event) {
1635 scan->event = VMEVENT_NONE;
1636 LIST_REMOVE(scan, entry);
1637 scan->func(m, scan);
1638 }
1639 }
1640}
1641
984263bc
MD
1642#include "opt_ddb.h"
1643#ifdef DDB
1644#include <sys/kernel.h>
1645
1646#include <ddb/ddb.h>
1647
1648DB_SHOW_COMMAND(page, vm_page_print_page_info)
1649{
12e4aaff
MD
1650 db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count);
1651 db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count);
1652 db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count);
1653 db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count);
1654 db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count);
1655 db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved);
1656 db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min);
1657 db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target);
1658 db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min);
1659 db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target);
984263bc
MD
1660}
1661
1662DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
1663{
1664 int i;
1665 db_printf("PQ_FREE:");
1666 for(i=0;i<PQ_L2_SIZE;i++) {
1667 db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt);
1668 }
1669 db_printf("\n");
1670
1671 db_printf("PQ_CACHE:");
1672 for(i=0;i<PQ_L2_SIZE;i++) {
1673 db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt);
1674 }
1675 db_printf("\n");
1676
1677 db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n",
1678 vm_page_queues[PQ_ACTIVE].lcnt,
1679 vm_page_queues[PQ_INACTIVE].lcnt);
1680}
1681#endif /* DDB */