uvm_page.c revision 1.82 1 /* $NetBSD: uvm_page.c,v 1.82 2003/01/27 02:10:20 enami Exp $ */
2
3 /*
4 * Copyright (c) 1997 Charles D. Cranor and Washington University.
5 * Copyright (c) 1991, 1993, The Regents of the University of California.
6 *
7 * All rights reserved.
8 *
9 * This code is derived from software contributed to Berkeley by
10 * The Mach Operating System project at Carnegie-Mellon University.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by Charles D. Cranor,
23 * Washington University, the University of California, Berkeley and
24 * its contributors.
25 * 4. Neither the name of the University nor the names of its contributors
26 * may be used to endorse or promote products derived from this software
27 * without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 * SUCH DAMAGE.
40 *
41 * @(#)vm_page.c 8.3 (Berkeley) 3/21/94
42 * from: Id: uvm_page.c,v 1.1.2.18 1998/02/06 05:24:42 chs Exp
43 *
44 *
45 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
46 * All rights reserved.
47 *
48 * Permission to use, copy, modify and distribute this software and
49 * its documentation is hereby granted, provided that both the copyright
50 * notice and this permission notice appear in all copies of the
51 * software, derivative works or modified versions, and any portions
52 * thereof, and that both notices appear in supporting documentation.
53 *
54 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
55 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
56 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
57 *
58 * Carnegie Mellon requests users of this software to return to
59 *
60 * Software Distribution Coordinator or Software.Distribution (at) CS.CMU.EDU
61 * School of Computer Science
62 * Carnegie Mellon University
63 * Pittsburgh PA 15213-3890
64 *
65 * any improvements or extensions that they make and grant Carnegie the
66 * rights to redistribute these changes.
67 */
68
69 /*
70 * uvm_page.c: page ops.
71 */
72
73 #include <sys/cdefs.h>
74 __KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.82 2003/01/27 02:10:20 enami Exp $");
75
76 #include "opt_uvmhist.h"
77
78 #include <sys/param.h>
79 #include <sys/systm.h>
80 #include <sys/malloc.h>
81 #include <sys/sched.h>
82 #include <sys/kernel.h>
83 #include <sys/vnode.h>
84 #include <sys/proc.h>
85
86 #define UVM_PAGE /* pull in uvm_page.h functions */
87 #include <uvm/uvm.h>
88
89 /*
90 * global vars... XXXCDC: move to uvm. structure.
91 */
92
93 /*
94 * physical memory config is stored in vm_physmem.
95 */
96
97 struct vm_physseg vm_physmem[VM_PHYSSEG_MAX]; /* XXXCDC: uvm.physmem */
98 int vm_nphysseg = 0; /* XXXCDC: uvm.nphysseg */
99
100 /*
101 * Some supported CPUs in a given architecture don't support all
102 * of the things necessary to do idle page zero'ing efficiently.
103 * We therefore provide a way to disable it from machdep code here.
104 */
105 /*
106 * XXX disabled until we can find a way to do this without causing
107 * problems for either cpu caches or DMA latency.
108 */
109 boolean_t vm_page_zero_enable = FALSE;
110
111 /*
112 * local variables
113 */
114
115 /*
116 * these variables record the values returned by vm_page_bootstrap,
117 * for debugging purposes. The implementation of uvm_pageboot_alloc
118 * and pmap_startup here also uses them internally.
119 */
120
121 static vaddr_t virtual_space_start;
122 static vaddr_t virtual_space_end;
123
124 /*
125 * we use a hash table with only one bucket during bootup. we will
126 * later rehash (resize) the hash table once the allocator is ready.
127 * we static allocate the one bootstrap bucket below...
128 */
129
130 static struct pglist uvm_bootbucket;
131
132 /*
133 * we allocate an initial number of page colors in uvm_page_init(),
134 * and remember them. We may re-color pages as cache sizes are
135 * discovered during the autoconfiguration phase. But we can never
136 * free the initial set of buckets, since they are allocated using
137 * uvm_pageboot_alloc().
138 */
139
140 static boolean_t have_recolored_pages /* = FALSE */;
141
142 /*
143 * local prototypes
144 */
145
146 static void uvm_pageinsert __P((struct vm_page *));
147 static void uvm_pageremove __P((struct vm_page *));
148
149 /*
150 * inline functions
151 */
152
153 /*
154 * uvm_pageinsert: insert a page in the object and the hash table
155 *
156 * => caller must lock object
157 * => caller must lock page queues
158 * => call should have already set pg's object and offset pointers
159 * and bumped the version counter
160 */
161
162 __inline static void
163 uvm_pageinsert(pg)
164 struct vm_page *pg;
165 {
166 struct pglist *buck;
167 struct uvm_object *uobj = pg->uobject;
168
169 KASSERT((pg->flags & PG_TABLED) == 0);
170 buck = &uvm.page_hash[uvm_pagehash(uobj, pg->offset)];
171 simple_lock(&uvm.hashlock);
172 TAILQ_INSERT_TAIL(buck, pg, hashq);
173 simple_unlock(&uvm.hashlock);
174
175 if (UVM_OBJ_IS_AOBJ(uobj)) {
176 uvmexp.anonpages++;
177 }
178
179 TAILQ_INSERT_TAIL(&uobj->memq, pg, listq);
180 pg->flags |= PG_TABLED;
181 uobj->uo_npages++;
182 }
183
184 /*
185 * uvm_page_remove: remove page from object and hash
186 *
187 * => caller must lock object
188 * => caller must lock page queues
189 */
190
191 static __inline void
192 uvm_pageremove(pg)
193 struct vm_page *pg;
194 {
195 struct pglist *buck;
196 struct uvm_object *uobj = pg->uobject;
197
198 KASSERT(pg->flags & PG_TABLED);
199 buck = &uvm.page_hash[uvm_pagehash(uobj, pg->offset)];
200 simple_lock(&uvm.hashlock);
201 TAILQ_REMOVE(buck, pg, hashq);
202 simple_unlock(&uvm.hashlock);
203
204 if (UVM_OBJ_IS_VTEXT(uobj)) {
205 uvmexp.execpages--;
206 } else if (UVM_OBJ_IS_VNODE(uobj)) {
207 uvmexp.filepages--;
208 } else if (UVM_OBJ_IS_AOBJ(uobj)) {
209 uvmexp.anonpages--;
210 }
211
212 /* object should be locked */
213 uobj->uo_npages--;
214 TAILQ_REMOVE(&uobj->memq, pg, listq);
215 pg->flags &= ~PG_TABLED;
216 pg->uobject = NULL;
217 }
218
219 static void
220 uvm_page_init_buckets(struct pgfreelist *pgfl)
221 {
222 int color, i;
223
224 for (color = 0; color < uvmexp.ncolors; color++) {
225 for (i = 0; i < PGFL_NQUEUES; i++) {
226 TAILQ_INIT(&pgfl->pgfl_buckets[
227 color].pgfl_queues[i]);
228 }
229 }
230 }
231
232 /*
233 * uvm_page_init: init the page system. called from uvm_init().
234 *
235 * => we return the range of kernel virtual memory in kvm_startp/kvm_endp
236 */
237
238 void
239 uvm_page_init(kvm_startp, kvm_endp)
240 vaddr_t *kvm_startp, *kvm_endp;
241 {
242 vsize_t freepages, pagecount, bucketcount, n;
243 struct pgflbucket *bucketarray;
244 struct vm_page *pagearray;
245 int lcv;
246 u_int i;
247 paddr_t paddr;
248
249 /*
250 * init the page queues and page queue locks, except the free
251 * list; we allocate that later (with the initial vm_page
252 * structures).
253 */
254
255 TAILQ_INIT(&uvm.page_active);
256 TAILQ_INIT(&uvm.page_inactive);
257 simple_lock_init(&uvm.pageqlock);
258 simple_lock_init(&uvm.fpageqlock);
259
260 /*
261 * init the <obj,offset> => <page> hash table. for now
262 * we just have one bucket (the bootstrap bucket). later on we
263 * will allocate new buckets as we dynamically resize the hash table.
264 */
265
266 uvm.page_nhash = 1; /* 1 bucket */
267 uvm.page_hashmask = 0; /* mask for hash function */
268 uvm.page_hash = &uvm_bootbucket; /* install bootstrap bucket */
269 TAILQ_INIT(uvm.page_hash); /* init hash table */
270 simple_lock_init(&uvm.hashlock); /* init hash table lock */
271
272 /*
273 * allocate vm_page structures.
274 */
275
276 /*
277 * sanity check:
278 * before calling this function the MD code is expected to register
279 * some free RAM with the uvm_page_physload() function. our job
280 * now is to allocate vm_page structures for this memory.
281 */
282
283 if (vm_nphysseg == 0)
284 panic("uvm_page_bootstrap: no memory pre-allocated");
285
286 /*
287 * first calculate the number of free pages...
288 *
289 * note that we use start/end rather than avail_start/avail_end.
290 * this allows us to allocate extra vm_page structures in case we
291 * want to return some memory to the pool after booting.
292 */
293
294 freepages = 0;
295 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
296 freepages += (vm_physmem[lcv].end - vm_physmem[lcv].start);
297
298 /*
299 * Let MD code initialize the number of colors, or default
300 * to 1 color if MD code doesn't care.
301 */
302 if (uvmexp.ncolors == 0)
303 uvmexp.ncolors = 1;
304 uvmexp.colormask = uvmexp.ncolors - 1;
305
306 /*
307 * we now know we have (PAGE_SIZE * freepages) bytes of memory we can
308 * use. for each page of memory we use we need a vm_page structure.
309 * thus, the total number of pages we can use is the total size of
310 * the memory divided by the PAGE_SIZE plus the size of the vm_page
311 * structure. we add one to freepages as a fudge factor to avoid
312 * truncation errors (since we can only allocate in terms of whole
313 * pages).
314 */
315
316 bucketcount = uvmexp.ncolors * VM_NFREELIST;
317 pagecount = ((freepages + 1) << PAGE_SHIFT) /
318 (PAGE_SIZE + sizeof(struct vm_page));
319
320 bucketarray = (void *)uvm_pageboot_alloc((bucketcount *
321 sizeof(struct pgflbucket)) + (pagecount *
322 sizeof(struct vm_page)));
323 pagearray = (struct vm_page *)(bucketarray + bucketcount);
324
325 for (lcv = 0; lcv < VM_NFREELIST; lcv++) {
326 uvm.page_free[lcv].pgfl_buckets =
327 (bucketarray + (lcv * uvmexp.ncolors));
328 uvm_page_init_buckets(&uvm.page_free[lcv]);
329 }
330 memset(pagearray, 0, pagecount * sizeof(struct vm_page));
331
332 /*
333 * init the vm_page structures and put them in the correct place.
334 */
335
336 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) {
337 n = vm_physmem[lcv].end - vm_physmem[lcv].start;
338
339 /* set up page array pointers */
340 vm_physmem[lcv].pgs = pagearray;
341 pagearray += n;
342 pagecount -= n;
343 vm_physmem[lcv].lastpg = vm_physmem[lcv].pgs + (n - 1);
344
345 /* init and free vm_pages (we've already zeroed them) */
346 paddr = ptoa(vm_physmem[lcv].start);
347 for (i = 0 ; i < n ; i++, paddr += PAGE_SIZE) {
348 vm_physmem[lcv].pgs[i].phys_addr = paddr;
349 #ifdef __HAVE_VM_PAGE_MD
350 VM_MDPAGE_INIT(&vm_physmem[lcv].pgs[i]);
351 #endif
352 if (atop(paddr) >= vm_physmem[lcv].avail_start &&
353 atop(paddr) <= vm_physmem[lcv].avail_end) {
354 uvmexp.npages++;
355 /* add page to free pool */
356 uvm_pagefree(&vm_physmem[lcv].pgs[i]);
357 }
358 }
359 }
360
361 /*
362 * pass up the values of virtual_space_start and
363 * virtual_space_end (obtained by uvm_pageboot_alloc) to the upper
364 * layers of the VM.
365 */
366
367 *kvm_startp = round_page(virtual_space_start);
368 *kvm_endp = trunc_page(virtual_space_end);
369
370 /*
371 * init locks for kernel threads
372 */
373
374 simple_lock_init(&uvm.pagedaemon_lock);
375 simple_lock_init(&uvm.aiodoned_lock);
376
377 /*
378 * init various thresholds.
379 */
380
381 uvmexp.reserve_pagedaemon = 1;
382 uvmexp.reserve_kernel = 5;
383 uvmexp.anonminpct = 10;
384 uvmexp.fileminpct = 10;
385 uvmexp.execminpct = 5;
386 uvmexp.anonmaxpct = 80;
387 uvmexp.filemaxpct = 50;
388 uvmexp.execmaxpct = 30;
389 uvmexp.anonmin = uvmexp.anonminpct * 256 / 100;
390 uvmexp.filemin = uvmexp.fileminpct * 256 / 100;
391 uvmexp.execmin = uvmexp.execminpct * 256 / 100;
392 uvmexp.anonmax = uvmexp.anonmaxpct * 256 / 100;
393 uvmexp.filemax = uvmexp.filemaxpct * 256 / 100;
394 uvmexp.execmax = uvmexp.execmaxpct * 256 / 100;
395
396 /*
397 * determine if we should zero pages in the idle loop.
398 */
399
400 uvm.page_idle_zero = vm_page_zero_enable;
401
402 /*
403 * done!
404 */
405
406 uvm.page_init_done = TRUE;
407 }
408
409 /*
410 * uvm_setpagesize: set the page size
411 *
412 * => sets page_shift and page_mask from uvmexp.pagesize.
413 */
414
415 void
416 uvm_setpagesize()
417 {
418 if (uvmexp.pagesize == 0)
419 uvmexp.pagesize = DEFAULT_PAGE_SIZE;
420 uvmexp.pagemask = uvmexp.pagesize - 1;
421 if ((uvmexp.pagemask & uvmexp.pagesize) != 0)
422 panic("uvm_setpagesize: page size not a power of two");
423 for (uvmexp.pageshift = 0; ; uvmexp.pageshift++)
424 if ((1 << uvmexp.pageshift) == uvmexp.pagesize)
425 break;
426 }
427
428 /*
429 * uvm_pageboot_alloc: steal memory from physmem for bootstrapping
430 */
431
432 vaddr_t
433 uvm_pageboot_alloc(size)
434 vsize_t size;
435 {
436 static boolean_t initialized = FALSE;
437 vaddr_t addr;
438 #if !defined(PMAP_STEAL_MEMORY)
439 vaddr_t vaddr;
440 paddr_t paddr;
441 #endif
442
443 /*
444 * on first call to this function, initialize ourselves.
445 */
446 if (initialized == FALSE) {
447 pmap_virtual_space(&virtual_space_start, &virtual_space_end);
448
449 /* round it the way we like it */
450 virtual_space_start = round_page(virtual_space_start);
451 virtual_space_end = trunc_page(virtual_space_end);
452
453 initialized = TRUE;
454 }
455
456 /* round to page size */
457 size = round_page(size);
458
459 #if defined(PMAP_STEAL_MEMORY)
460
461 /*
462 * defer bootstrap allocation to MD code (it may want to allocate
463 * from a direct-mapped segment). pmap_steal_memory should adjust
464 * virtual_space_start/virtual_space_end if necessary.
465 */
466
467 addr = pmap_steal_memory(size, &virtual_space_start,
468 &virtual_space_end);
469
470 return(addr);
471
472 #else /* !PMAP_STEAL_MEMORY */
473
474 /*
475 * allocate virtual memory for this request
476 */
477 if (virtual_space_start == virtual_space_end ||
478 (virtual_space_end - virtual_space_start) < size)
479 panic("uvm_pageboot_alloc: out of virtual space");
480
481 addr = virtual_space_start;
482
483 #ifdef PMAP_GROWKERNEL
484 /*
485 * If the kernel pmap can't map the requested space,
486 * then allocate more resources for it.
487 */
488 if (uvm_maxkaddr < (addr + size)) {
489 uvm_maxkaddr = pmap_growkernel(addr + size);
490 if (uvm_maxkaddr < (addr + size))
491 panic("uvm_pageboot_alloc: pmap_growkernel() failed");
492 }
493 #endif
494
495 virtual_space_start += size;
496
497 /*
498 * allocate and mapin physical pages to back new virtual pages
499 */
500
501 for (vaddr = round_page(addr) ; vaddr < addr + size ;
502 vaddr += PAGE_SIZE) {
503
504 if (!uvm_page_physget(&paddr))
505 panic("uvm_pageboot_alloc: out of memory");
506
507 /*
508 * Note this memory is no longer managed, so using
509 * pmap_kenter is safe.
510 */
511 pmap_kenter_pa(vaddr, paddr, VM_PROT_READ|VM_PROT_WRITE);
512 }
513 pmap_update(pmap_kernel());
514 return(addr);
515 #endif /* PMAP_STEAL_MEMORY */
516 }
517
518 #if !defined(PMAP_STEAL_MEMORY)
519 /*
520 * uvm_page_physget: "steal" one page from the vm_physmem structure.
521 *
522 * => attempt to allocate it off the end of a segment in which the "avail"
523 * values match the start/end values. if we can't do that, then we
524 * will advance both values (making them equal, and removing some
525 * vm_page structures from the non-avail area).
526 * => return false if out of memory.
527 */
528
529 /* subroutine: try to allocate from memory chunks on the specified freelist */
530 static boolean_t uvm_page_physget_freelist __P((paddr_t *, int));
531
532 static boolean_t
533 uvm_page_physget_freelist(paddrp, freelist)
534 paddr_t *paddrp;
535 int freelist;
536 {
537 int lcv, x;
538
539 /* pass 1: try allocating from a matching end */
540 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST)
541 for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--)
542 #else
543 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
544 #endif
545 {
546
547 if (uvm.page_init_done == TRUE)
548 panic("uvm_page_physget: called _after_ bootstrap");
549
550 if (vm_physmem[lcv].free_list != freelist)
551 continue;
552
553 /* try from front */
554 if (vm_physmem[lcv].avail_start == vm_physmem[lcv].start &&
555 vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) {
556 *paddrp = ptoa(vm_physmem[lcv].avail_start);
557 vm_physmem[lcv].avail_start++;
558 vm_physmem[lcv].start++;
559 /* nothing left? nuke it */
560 if (vm_physmem[lcv].avail_start ==
561 vm_physmem[lcv].end) {
562 if (vm_nphysseg == 1)
563 panic("vum_page_physget: out of memory!");
564 vm_nphysseg--;
565 for (x = lcv ; x < vm_nphysseg ; x++)
566 /* structure copy */
567 vm_physmem[x] = vm_physmem[x+1];
568 }
569 return (TRUE);
570 }
571
572 /* try from rear */
573 if (vm_physmem[lcv].avail_end == vm_physmem[lcv].end &&
574 vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) {
575 *paddrp = ptoa(vm_physmem[lcv].avail_end - 1);
576 vm_physmem[lcv].avail_end--;
577 vm_physmem[lcv].end--;
578 /* nothing left? nuke it */
579 if (vm_physmem[lcv].avail_end ==
580 vm_physmem[lcv].start) {
581 if (vm_nphysseg == 1)
582 panic("uvm_page_physget: out of memory!");
583 vm_nphysseg--;
584 for (x = lcv ; x < vm_nphysseg ; x++)
585 /* structure copy */
586 vm_physmem[x] = vm_physmem[x+1];
587 }
588 return (TRUE);
589 }
590 }
591
592 /* pass2: forget about matching ends, just allocate something */
593 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST)
594 for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--)
595 #else
596 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
597 #endif
598 {
599
600 /* any room in this bank? */
601 if (vm_physmem[lcv].avail_start >= vm_physmem[lcv].avail_end)
602 continue; /* nope */
603
604 *paddrp = ptoa(vm_physmem[lcv].avail_start);
605 vm_physmem[lcv].avail_start++;
606 /* truncate! */
607 vm_physmem[lcv].start = vm_physmem[lcv].avail_start;
608
609 /* nothing left? nuke it */
610 if (vm_physmem[lcv].avail_start == vm_physmem[lcv].end) {
611 if (vm_nphysseg == 1)
612 panic("uvm_page_physget: out of memory!");
613 vm_nphysseg--;
614 for (x = lcv ; x < vm_nphysseg ; x++)
615 /* structure copy */
616 vm_physmem[x] = vm_physmem[x+1];
617 }
618 return (TRUE);
619 }
620
621 return (FALSE); /* whoops! */
622 }
623
624 boolean_t
625 uvm_page_physget(paddrp)
626 paddr_t *paddrp;
627 {
628 int i;
629
630 /* try in the order of freelist preference */
631 for (i = 0; i < VM_NFREELIST; i++)
632 if (uvm_page_physget_freelist(paddrp, i) == TRUE)
633 return (TRUE);
634 return (FALSE);
635 }
636 #endif /* PMAP_STEAL_MEMORY */
637
638 /*
639 * uvm_page_physload: load physical memory into VM system
640 *
641 * => all args are PFs
642 * => all pages in start/end get vm_page structures
643 * => areas marked by avail_start/avail_end get added to the free page pool
644 * => we are limited to VM_PHYSSEG_MAX physical memory segments
645 */
646
647 void
648 uvm_page_physload(start, end, avail_start, avail_end, free_list)
649 paddr_t start, end, avail_start, avail_end;
650 int free_list;
651 {
652 int preload, lcv;
653 psize_t npages;
654 struct vm_page *pgs;
655 struct vm_physseg *ps;
656
657 if (uvmexp.pagesize == 0)
658 panic("uvm_page_physload: page size not set!");
659 if (free_list >= VM_NFREELIST || free_list < VM_FREELIST_DEFAULT)
660 panic("uvm_page_physload: bad free list %d", free_list);
661 if (start >= end)
662 panic("uvm_page_physload: start >= end");
663
664 /*
665 * do we have room?
666 */
667
668 if (vm_nphysseg == VM_PHYSSEG_MAX) {
669 printf("uvm_page_physload: unable to load physical memory "
670 "segment\n");
671 printf("\t%d segments allocated, ignoring 0x%llx -> 0x%llx\n",
672 VM_PHYSSEG_MAX, (long long)start, (long long)end);
673 printf("\tincrease VM_PHYSSEG_MAX\n");
674 return;
675 }
676
677 /*
678 * check to see if this is a "preload" (i.e. uvm_mem_init hasn't been
679 * called yet, so malloc is not available).
680 */
681
682 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) {
683 if (vm_physmem[lcv].pgs)
684 break;
685 }
686 preload = (lcv == vm_nphysseg);
687
688 /*
689 * if VM is already running, attempt to malloc() vm_page structures
690 */
691
692 if (!preload) {
693 #if defined(VM_PHYSSEG_NOADD)
694 panic("uvm_page_physload: tried to add RAM after vm_mem_init");
695 #else
696 /* XXXCDC: need some sort of lockout for this case */
697 paddr_t paddr;
698 npages = end - start; /* # of pages */
699 pgs = malloc(sizeof(struct vm_page) * npages,
700 M_VMPAGE, M_NOWAIT);
701 if (pgs == NULL) {
702 printf("uvm_page_physload: can not malloc vm_page "
703 "structs for segment\n");
704 printf("\tignoring 0x%lx -> 0x%lx\n", start, end);
705 return;
706 }
707 /* zero data, init phys_addr and free_list, and free pages */
708 memset(pgs, 0, sizeof(struct vm_page) * npages);
709 for (lcv = 0, paddr = ptoa(start) ;
710 lcv < npages ; lcv++, paddr += PAGE_SIZE) {
711 pgs[lcv].phys_addr = paddr;
712 pgs[lcv].free_list = free_list;
713 if (atop(paddr) >= avail_start &&
714 atop(paddr) <= avail_end)
715 uvm_pagefree(&pgs[lcv]);
716 }
717 /* XXXCDC: incomplete: need to update uvmexp.free, what else? */
718 /* XXXCDC: need hook to tell pmap to rebuild pv_list, etc... */
719 #endif
720 } else {
721 pgs = NULL;
722 npages = 0;
723 }
724
725 /*
726 * now insert us in the proper place in vm_physmem[]
727 */
728
729 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_RANDOM)
730 /* random: put it at the end (easy!) */
731 ps = &vm_physmem[vm_nphysseg];
732 #elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BSEARCH)
733 {
734 int x;
735 /* sort by address for binary search */
736 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
737 if (start < vm_physmem[lcv].start)
738 break;
739 ps = &vm_physmem[lcv];
740 /* move back other entries, if necessary ... */
741 for (x = vm_nphysseg ; x > lcv ; x--)
742 /* structure copy */
743 vm_physmem[x] = vm_physmem[x - 1];
744 }
745 #elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST)
746 {
747 int x;
748 /* sort by largest segment first */
749 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
750 if ((end - start) >
751 (vm_physmem[lcv].end - vm_physmem[lcv].start))
752 break;
753 ps = &vm_physmem[lcv];
754 /* move back other entries, if necessary ... */
755 for (x = vm_nphysseg ; x > lcv ; x--)
756 /* structure copy */
757 vm_physmem[x] = vm_physmem[x - 1];
758 }
759 #else
760 panic("uvm_page_physload: unknown physseg strategy selected!");
761 #endif
762
763 ps->start = start;
764 ps->end = end;
765 ps->avail_start = avail_start;
766 ps->avail_end = avail_end;
767 if (preload) {
768 ps->pgs = NULL;
769 } else {
770 ps->pgs = pgs;
771 ps->lastpg = pgs + npages - 1;
772 }
773 ps->free_list = free_list;
774 vm_nphysseg++;
775
776 if (!preload)
777 uvm_page_rehash();
778 }
779
780 /*
781 * uvm_page_rehash: reallocate hash table based on number of free pages.
782 */
783
784 void
785 uvm_page_rehash()
786 {
787 int freepages, lcv, bucketcount, oldcount;
788 struct pglist *newbuckets, *oldbuckets;
789 struct vm_page *pg;
790 size_t newsize, oldsize;
791
792 /*
793 * compute number of pages that can go in the free pool
794 */
795
796 freepages = 0;
797 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
798 freepages +=
799 (vm_physmem[lcv].avail_end - vm_physmem[lcv].avail_start);
800
801 /*
802 * compute number of buckets needed for this number of pages
803 */
804
805 bucketcount = 1;
806 while (bucketcount < freepages)
807 bucketcount = bucketcount * 2;
808
809 /*
810 * compute the size of the current table and new table.
811 */
812
813 oldbuckets = uvm.page_hash;
814 oldcount = uvm.page_nhash;
815 oldsize = round_page(sizeof(struct pglist) * oldcount);
816 newsize = round_page(sizeof(struct pglist) * bucketcount);
817
818 /*
819 * allocate the new buckets
820 */
821
822 newbuckets = (struct pglist *) uvm_km_alloc(kernel_map, newsize);
823 if (newbuckets == NULL) {
824 printf("uvm_page_physrehash: WARNING: could not grow page "
825 "hash table\n");
826 return;
827 }
828 for (lcv = 0 ; lcv < bucketcount ; lcv++)
829 TAILQ_INIT(&newbuckets[lcv]);
830
831 /*
832 * now replace the old buckets with the new ones and rehash everything
833 */
834
835 simple_lock(&uvm.hashlock);
836 uvm.page_hash = newbuckets;
837 uvm.page_nhash = bucketcount;
838 uvm.page_hashmask = bucketcount - 1; /* power of 2 */
839
840 /* ... and rehash */
841 for (lcv = 0 ; lcv < oldcount ; lcv++) {
842 while ((pg = oldbuckets[lcv].tqh_first) != NULL) {
843 TAILQ_REMOVE(&oldbuckets[lcv], pg, hashq);
844 TAILQ_INSERT_TAIL(
845 &uvm.page_hash[uvm_pagehash(pg->uobject, pg->offset)],
846 pg, hashq);
847 }
848 }
849 simple_unlock(&uvm.hashlock);
850
851 /*
852 * free old bucket array if is not the boot-time table
853 */
854
855 if (oldbuckets != &uvm_bootbucket)
856 uvm_km_free(kernel_map, (vaddr_t) oldbuckets, oldsize);
857 }
858
859 /*
860 * uvm_page_recolor: Recolor the pages if the new bucket count is
861 * larger than the old one.
862 */
863
864 void
865 uvm_page_recolor(int newncolors)
866 {
867 struct pgflbucket *bucketarray, *oldbucketarray;
868 struct pgfreelist pgfl;
869 struct vm_page *pg;
870 vsize_t bucketcount;
871 int s, lcv, color, i, ocolors;
872
873 if (newncolors <= uvmexp.ncolors)
874 return;
875
876 if (uvm.page_init_done == FALSE) {
877 uvmexp.ncolors = newncolors;
878 return;
879 }
880
881 bucketcount = newncolors * VM_NFREELIST;
882 bucketarray = malloc(bucketcount * sizeof(struct pgflbucket),
883 M_VMPAGE, M_NOWAIT);
884 if (bucketarray == NULL) {
885 printf("WARNING: unable to allocate %ld page color buckets\n",
886 (long) bucketcount);
887 return;
888 }
889
890 s = uvm_lock_fpageq();
891
892 /* Make sure we should still do this. */
893 if (newncolors <= uvmexp.ncolors) {
894 uvm_unlock_fpageq(s);
895 free(bucketarray, M_VMPAGE);
896 return;
897 }
898
899 oldbucketarray = uvm.page_free[0].pgfl_buckets;
900 ocolors = uvmexp.ncolors;
901
902 uvmexp.ncolors = newncolors;
903 uvmexp.colormask = uvmexp.ncolors - 1;
904
905 for (lcv = 0; lcv < VM_NFREELIST; lcv++) {
906 pgfl.pgfl_buckets = (bucketarray + (lcv * newncolors));
907 uvm_page_init_buckets(&pgfl);
908 for (color = 0; color < ocolors; color++) {
909 for (i = 0; i < PGFL_NQUEUES; i++) {
910 while ((pg = TAILQ_FIRST(&uvm.page_free[
911 lcv].pgfl_buckets[color].pgfl_queues[i]))
912 != NULL) {
913 TAILQ_REMOVE(&uvm.page_free[
914 lcv].pgfl_buckets[
915 color].pgfl_queues[i], pg, pageq);
916 TAILQ_INSERT_TAIL(&pgfl.pgfl_buckets[
917 VM_PGCOLOR_BUCKET(pg)].pgfl_queues[
918 i], pg, pageq);
919 }
920 }
921 }
922 uvm.page_free[lcv].pgfl_buckets = pgfl.pgfl_buckets;
923 }
924
925 if (have_recolored_pages) {
926 uvm_unlock_fpageq(s);
927 free(oldbucketarray, M_VMPAGE);
928 return;
929 }
930
931 have_recolored_pages = TRUE;
932 uvm_unlock_fpageq(s);
933 }
934
935 /*
936 * uvm_pagealloc_pgfl: helper routine for uvm_pagealloc_strat
937 */
938
939 static __inline struct vm_page *
940 uvm_pagealloc_pgfl(struct pgfreelist *pgfl, int try1, int try2,
941 int *trycolorp)
942 {
943 struct pglist *freeq;
944 struct vm_page *pg;
945 int color, trycolor = *trycolorp;
946
947 color = trycolor;
948 do {
949 if ((pg = TAILQ_FIRST((freeq =
950 &pgfl->pgfl_buckets[color].pgfl_queues[try1]))) != NULL)
951 goto gotit;
952 if ((pg = TAILQ_FIRST((freeq =
953 &pgfl->pgfl_buckets[color].pgfl_queues[try2]))) != NULL)
954 goto gotit;
955 color = (color + 1) & uvmexp.colormask;
956 } while (color != trycolor);
957
958 return (NULL);
959
960 gotit:
961 TAILQ_REMOVE(freeq, pg, pageq);
962 uvmexp.free--;
963
964 /* update zero'd page count */
965 if (pg->flags & PG_ZERO)
966 uvmexp.zeropages--;
967
968 if (color == trycolor)
969 uvmexp.colorhit++;
970 else {
971 uvmexp.colormiss++;
972 *trycolorp = color;
973 }
974
975 return (pg);
976 }
977
978 /*
979 * uvm_pagealloc_strat: allocate vm_page from a particular free list.
980 *
981 * => return null if no pages free
982 * => wake up pagedaemon if number of free pages drops below low water mark
983 * => if obj != NULL, obj must be locked (to put in hash)
984 * => if anon != NULL, anon must be locked (to put in anon)
985 * => only one of obj or anon can be non-null
986 * => caller must activate/deactivate page if it is not wired.
987 * => free_list is ignored if strat == UVM_PGA_STRAT_NORMAL.
988 * => policy decision: it is more important to pull a page off of the
989 * appropriate priority free list than it is to get a zero'd or
990 * unknown contents page. This is because we live with the
991 * consequences of a bad free list decision for the entire
992 * lifetime of the page, e.g. if the page comes from memory that
993 * is slower to access.
994 */
995
996 struct vm_page *
997 uvm_pagealloc_strat(obj, off, anon, flags, strat, free_list)
998 struct uvm_object *obj;
999 voff_t off;
1000 int flags;
1001 struct vm_anon *anon;
1002 int strat, free_list;
1003 {
1004 int lcv, try1, try2, s, zeroit = 0, color;
1005 struct vm_page *pg;
1006 boolean_t use_reserve;
1007
1008 KASSERT(obj == NULL || anon == NULL);
1009 KASSERT(off == trunc_page(off));
1010 LOCK_ASSERT(obj == NULL || simple_lock_held(&obj->vmobjlock));
1011 LOCK_ASSERT(anon == NULL || simple_lock_held(&anon->an_lock));
1012
1013 s = uvm_lock_fpageq();
1014
1015 /*
1016 * This implements a global round-robin page coloring
1017 * algorithm.
1018 *
1019 * XXXJRT: Should we make the `nextcolor' per-cpu?
1020 * XXXJRT: What about virtually-indexed caches?
1021 */
1022
1023 color = uvm.page_free_nextcolor;
1024
1025 /*
1026 * check to see if we need to generate some free pages waking
1027 * the pagedaemon.
1028 */
1029
1030 UVM_KICK_PDAEMON();
1031
1032 /*
1033 * fail if any of these conditions is true:
1034 * [1] there really are no free pages, or
1035 * [2] only kernel "reserved" pages remain and
1036 * the page isn't being allocated to a kernel object.
1037 * [3] only pagedaemon "reserved" pages remain and
1038 * the requestor isn't the pagedaemon.
1039 */
1040
1041 use_reserve = (flags & UVM_PGA_USERESERVE) ||
1042 (obj && UVM_OBJ_IS_KERN_OBJECT(obj));
1043 if ((uvmexp.free <= uvmexp.reserve_kernel && !use_reserve) ||
1044 (uvmexp.free <= uvmexp.reserve_pagedaemon &&
1045 !(use_reserve && curproc == uvm.pagedaemon_proc)))
1046 goto fail;
1047
1048 #if PGFL_NQUEUES != 2
1049 #error uvm_pagealloc_strat needs to be updated
1050 #endif
1051
1052 /*
1053 * If we want a zero'd page, try the ZEROS queue first, otherwise
1054 * we try the UNKNOWN queue first.
1055 */
1056 if (flags & UVM_PGA_ZERO) {
1057 try1 = PGFL_ZEROS;
1058 try2 = PGFL_UNKNOWN;
1059 } else {
1060 try1 = PGFL_UNKNOWN;
1061 try2 = PGFL_ZEROS;
1062 }
1063
1064 again:
1065 switch (strat) {
1066 case UVM_PGA_STRAT_NORMAL:
1067 /* Check all freelists in descending priority order. */
1068 for (lcv = 0; lcv < VM_NFREELIST; lcv++) {
1069 pg = uvm_pagealloc_pgfl(&uvm.page_free[lcv],
1070 try1, try2, &color);
1071 if (pg != NULL)
1072 goto gotit;
1073 }
1074
1075 /* No pages free! */
1076 goto fail;
1077
1078 case UVM_PGA_STRAT_ONLY:
1079 case UVM_PGA_STRAT_FALLBACK:
1080 /* Attempt to allocate from the specified free list. */
1081 KASSERT(free_list >= 0 && free_list < VM_NFREELIST);
1082 pg = uvm_pagealloc_pgfl(&uvm.page_free[free_list],
1083 try1, try2, &color);
1084 if (pg != NULL)
1085 goto gotit;
1086
1087 /* Fall back, if possible. */
1088 if (strat == UVM_PGA_STRAT_FALLBACK) {
1089 strat = UVM_PGA_STRAT_NORMAL;
1090 goto again;
1091 }
1092
1093 /* No pages free! */
1094 goto fail;
1095
1096 default:
1097 panic("uvm_pagealloc_strat: bad strat %d", strat);
1098 /* NOTREACHED */
1099 }
1100
1101 gotit:
1102 /*
1103 * We now know which color we actually allocated from; set
1104 * the next color accordingly.
1105 */
1106
1107 uvm.page_free_nextcolor = (color + 1) & uvmexp.colormask;
1108
1109 /*
1110 * update allocation statistics and remember if we have to
1111 * zero the page
1112 */
1113
1114 if (flags & UVM_PGA_ZERO) {
1115 if (pg->flags & PG_ZERO) {
1116 uvmexp.pga_zerohit++;
1117 zeroit = 0;
1118 } else {
1119 uvmexp.pga_zeromiss++;
1120 zeroit = 1;
1121 }
1122 }
1123 uvm_unlock_fpageq(s);
1124
1125 pg->offset = off;
1126 pg->uobject = obj;
1127 pg->uanon = anon;
1128 pg->flags = PG_BUSY|PG_CLEAN|PG_FAKE;
1129 if (anon) {
1130 anon->u.an_page = pg;
1131 pg->pqflags = PQ_ANON;
1132 uvmexp.anonpages++;
1133 } else {
1134 if (obj) {
1135 uvm_pageinsert(pg);
1136 }
1137 pg->pqflags = 0;
1138 }
1139 #if defined(UVM_PAGE_TRKOWN)
1140 pg->owner_tag = NULL;
1141 #endif
1142 UVM_PAGE_OWN(pg, "new alloc");
1143
1144 if (flags & UVM_PGA_ZERO) {
1145 /*
1146 * A zero'd page is not clean. If we got a page not already
1147 * zero'd, then we have to zero it ourselves.
1148 */
1149 pg->flags &= ~PG_CLEAN;
1150 if (zeroit)
1151 pmap_zero_page(VM_PAGE_TO_PHYS(pg));
1152 }
1153
1154 return(pg);
1155
1156 fail:
1157 uvm_unlock_fpageq(s);
1158 return (NULL);
1159 }
1160
1161 /*
1162 * uvm_pagerealloc: reallocate a page from one object to another
1163 *
1164 * => both objects must be locked
1165 */
1166
1167 void
1168 uvm_pagerealloc(pg, newobj, newoff)
1169 struct vm_page *pg;
1170 struct uvm_object *newobj;
1171 voff_t newoff;
1172 {
1173 /*
1174 * remove it from the old object
1175 */
1176
1177 if (pg->uobject) {
1178 uvm_pageremove(pg);
1179 }
1180
1181 /*
1182 * put it in the new object
1183 */
1184
1185 if (newobj) {
1186 pg->uobject = newobj;
1187 pg->offset = newoff;
1188 uvm_pageinsert(pg);
1189 }
1190 }
1191
1192 /*
1193 * uvm_pagefree: free page
1194 *
1195 * => erase page's identity (i.e. remove from hash/object)
1196 * => put page on free list
1197 * => caller must lock owning object (either anon or uvm_object)
1198 * => caller must lock page queues
1199 * => assumes all valid mappings of pg are gone
1200 */
1201
1202 void
1203 uvm_pagefree(pg)
1204 struct vm_page *pg;
1205 {
1206 int s;
1207
1208 KASSERT((pg->flags & PG_PAGEOUT) == 0);
1209 LOCK_ASSERT(simple_lock_held(&uvm.pageqlock) ||
1210 (pg->pqflags & (PQ_ACTIVE|PQ_INACTIVE)) == 0);
1211 LOCK_ASSERT(pg->uobject == NULL ||
1212 simple_lock_held(&pg->uobject->vmobjlock));
1213 LOCK_ASSERT(pg->uobject != NULL || pg->uanon == NULL ||
1214 simple_lock_held(&pg->uanon->an_lock));
1215
1216 #ifdef DEBUG
1217 if (pg->uobject == (void *)0xdeadbeef &&
1218 pg->uanon == (void *)0xdeadbeef) {
1219 panic("uvm_pagefree: freeing free page %p", pg);
1220 }
1221 #endif
1222
1223 /*
1224 * if the page is loaned, resolve the loan instead of freeing.
1225 */
1226
1227 if (pg->loan_count) {
1228 KASSERT(pg->wire_count == 0);
1229
1230 /*
1231 * if the page is owned by an anon then we just want to
1232 * drop anon ownership. the kernel will free the page when
1233 * it is done with it. if the page is owned by an object,
1234 * remove it from the object and mark it dirty for the benefit
1235 * of possible anon owners.
1236 *
1237 * regardless of previous ownership, wakeup any waiters,
1238 * unbusy the page, and we're done.
1239 */
1240
1241 if (pg->uobject != NULL) {
1242 uvm_pageremove(pg);
1243 pg->flags &= ~PG_CLEAN;
1244 } else if (pg->uanon != NULL) {
1245 if ((pg->pqflags & PQ_ANON) == 0) {
1246 pg->loan_count--;
1247 } else {
1248 pg->pqflags &= ~PQ_ANON;
1249 }
1250 pg->uanon = NULL;
1251 }
1252 if (pg->flags & PG_WANTED) {
1253 wakeup(pg);
1254 }
1255 pg->flags &= ~(PG_WANTED|PG_BUSY|PG_RELEASED);
1256 #ifdef UVM_PAGE_TRKOWN
1257 pg->owner_tag = NULL;
1258 #endif
1259 if (pg->loan_count) {
1260 uvm_pagedequeue(pg);
1261 return;
1262 }
1263 }
1264
1265 /*
1266 * remove page from its object or anon.
1267 */
1268
1269 if (pg->uobject != NULL) {
1270 uvm_pageremove(pg);
1271 } else if (pg->uanon != NULL) {
1272 pg->uanon->u.an_page = NULL;
1273 uvmexp.anonpages--;
1274 }
1275
1276 /*
1277 * now remove the page from the queues.
1278 */
1279
1280 uvm_pagedequeue(pg);
1281
1282 /*
1283 * if the page was wired, unwire it now.
1284 */
1285
1286 if (pg->wire_count) {
1287 pg->wire_count = 0;
1288 uvmexp.wired--;
1289 }
1290
1291 /*
1292 * and put on free queue
1293 */
1294
1295 pg->flags &= ~PG_ZERO;
1296
1297 s = uvm_lock_fpageq();
1298 TAILQ_INSERT_TAIL(&uvm.page_free[
1299 uvm_page_lookup_freelist(pg)].pgfl_buckets[
1300 VM_PGCOLOR_BUCKET(pg)].pgfl_queues[PGFL_UNKNOWN], pg, pageq);
1301 pg->pqflags = PQ_FREE;
1302 #ifdef DEBUG
1303 pg->uobject = (void *)0xdeadbeef;
1304 pg->offset = 0xdeadbeef;
1305 pg->uanon = (void *)0xdeadbeef;
1306 #endif
1307 uvmexp.free++;
1308
1309 if (uvmexp.zeropages < UVM_PAGEZERO_TARGET)
1310 uvm.page_idle_zero = vm_page_zero_enable;
1311
1312 uvm_unlock_fpageq(s);
1313 }
1314
1315 /*
1316 * uvm_page_unbusy: unbusy an array of pages.
1317 *
1318 * => pages must either all belong to the same object, or all belong to anons.
1319 * => if pages are object-owned, object must be locked.
1320 * => if pages are anon-owned, anons must be locked.
1321 * => caller must lock page queues if pages may be released.
1322 */
1323
1324 void
1325 uvm_page_unbusy(pgs, npgs)
1326 struct vm_page **pgs;
1327 int npgs;
1328 {
1329 struct vm_page *pg;
1330 int i;
1331 UVMHIST_FUNC("uvm_page_unbusy"); UVMHIST_CALLED(ubchist);
1332
1333 for (i = 0; i < npgs; i++) {
1334 pg = pgs[i];
1335 if (pg == NULL || pg == PGO_DONTCARE) {
1336 continue;
1337 }
1338 if (pg->flags & PG_WANTED) {
1339 wakeup(pg);
1340 }
1341 if (pg->flags & PG_RELEASED) {
1342 UVMHIST_LOG(ubchist, "releasing pg %p", pg,0,0,0);
1343 pg->flags &= ~PG_RELEASED;
1344 uvm_pagefree(pg);
1345 } else {
1346 UVMHIST_LOG(ubchist, "unbusying pg %p", pg,0,0,0);
1347 pg->flags &= ~(PG_WANTED|PG_BUSY);
1348 UVM_PAGE_OWN(pg, NULL);
1349 }
1350 }
1351 }
1352
1353 #if defined(UVM_PAGE_TRKOWN)
1354 /*
1355 * uvm_page_own: set or release page ownership
1356 *
1357 * => this is a debugging function that keeps track of who sets PG_BUSY
1358 * and where they do it. it can be used to track down problems
1359 * such a process setting "PG_BUSY" and never releasing it.
1360 * => page's object [if any] must be locked
1361 * => if "tag" is NULL then we are releasing page ownership
1362 */
1363 void
1364 uvm_page_own(pg, tag)
1365 struct vm_page *pg;
1366 char *tag;
1367 {
1368 KASSERT((pg->flags & (PG_PAGEOUT|PG_RELEASED)) == 0);
1369
1370 /* gain ownership? */
1371 if (tag) {
1372 if (pg->owner_tag) {
1373 printf("uvm_page_own: page %p already owned "
1374 "by proc %d [%s]\n", pg,
1375 pg->owner, pg->owner_tag);
1376 panic("uvm_page_own");
1377 }
1378 pg->owner = (curproc) ? curproc->p_pid : (pid_t) -1;
1379 pg->owner_tag = tag;
1380 return;
1381 }
1382
1383 /* drop ownership */
1384 if (pg->owner_tag == NULL) {
1385 printf("uvm_page_own: dropping ownership of an non-owned "
1386 "page (%p)\n", pg);
1387 panic("uvm_page_own");
1388 }
1389 KASSERT((pg->pqflags & (PQ_ACTIVE|PQ_INACTIVE)) ||
1390 (pg->uanon == NULL && pg->uobject == NULL) ||
1391 pg->uobject == uvm.kernel_object ||
1392 pg->wire_count > 0 ||
1393 (pg->loan_count == 1 && pg->uanon == NULL) ||
1394 pg->loan_count > 1);
1395 pg->owner_tag = NULL;
1396 }
1397 #endif
1398
1399 /*
1400 * uvm_pageidlezero: zero free pages while the system is idle.
1401 *
1402 * => try to complete one color bucket at a time, to reduce our impact
1403 * on the CPU cache.
1404 * => we loop until we either reach the target or whichqs indicates that
1405 * there is a process ready to run.
1406 */
1407 void
1408 uvm_pageidlezero()
1409 {
1410 struct vm_page *pg;
1411 struct pgfreelist *pgfl;
1412 int free_list, s, firstbucket;
1413 static int nextbucket;
1414
1415 s = uvm_lock_fpageq();
1416 firstbucket = nextbucket;
1417 do {
1418 if (sched_whichqs != 0) {
1419 uvm_unlock_fpageq(s);
1420 return;
1421 }
1422 if (uvmexp.zeropages >= UVM_PAGEZERO_TARGET) {
1423 uvm.page_idle_zero = FALSE;
1424 uvm_unlock_fpageq(s);
1425 return;
1426 }
1427 for (free_list = 0; free_list < VM_NFREELIST; free_list++) {
1428 pgfl = &uvm.page_free[free_list];
1429 while ((pg = TAILQ_FIRST(&pgfl->pgfl_buckets[
1430 nextbucket].pgfl_queues[PGFL_UNKNOWN])) != NULL) {
1431 if (sched_whichqs != 0) {
1432 uvm_unlock_fpageq(s);
1433 return;
1434 }
1435
1436 TAILQ_REMOVE(&pgfl->pgfl_buckets[
1437 nextbucket].pgfl_queues[PGFL_UNKNOWN],
1438 pg, pageq);
1439 uvmexp.free--;
1440 uvm_unlock_fpageq(s);
1441 #ifdef PMAP_PAGEIDLEZERO
1442 if (!PMAP_PAGEIDLEZERO(VM_PAGE_TO_PHYS(pg))) {
1443
1444 /*
1445 * The machine-dependent code detected
1446 * some reason for us to abort zeroing
1447 * pages, probably because there is a
1448 * process now ready to run.
1449 */
1450
1451 s = uvm_lock_fpageq();
1452 TAILQ_INSERT_HEAD(&pgfl->pgfl_buckets[
1453 nextbucket].pgfl_queues[
1454 PGFL_UNKNOWN], pg, pageq);
1455 uvmexp.free++;
1456 uvmexp.zeroaborts++;
1457 uvm_unlock_fpageq(s);
1458 return;
1459 }
1460 #else
1461 pmap_zero_page(VM_PAGE_TO_PHYS(pg));
1462 #endif /* PMAP_PAGEIDLEZERO */
1463 pg->flags |= PG_ZERO;
1464
1465 s = uvm_lock_fpageq();
1466 TAILQ_INSERT_HEAD(&pgfl->pgfl_buckets[
1467 nextbucket].pgfl_queues[PGFL_ZEROS],
1468 pg, pageq);
1469 uvmexp.free++;
1470 uvmexp.zeropages++;
1471 }
1472 }
1473 nextbucket = (nextbucket + 1) & uvmexp.colormask;
1474 } while (nextbucket != firstbucket);
1475 uvm_unlock_fpageq(s);
1476 }
1477