1 /* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. 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.h 8.2 (Berkeley) 12/13/93 37 * 38 * 39 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 40 * All rights reserved. 41 * 42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 43 * 44 * Permission to use, copy, modify and distribute this software and 45 * its documentation is hereby granted, provided that both the copyright 46 * notice and this permission notice appear in all copies of the 47 * software, derivative works or modified versions, and any portions 48 * thereof, and that both notices appear in supporting documentation. 49 * 50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 53 * 54 * Carnegie Mellon requests users of this software to return to 55 * 56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 57 * School of Computer Science 58 * Carnegie Mellon University 59 * Pittsburgh PA 15213-3890 60 * 61 * any improvements or extensions that they make and grant Carnegie the 62 * rights to redistribute these changes. 63 * 64 * $FreeBSD: src/sys/vm/vm_page.h,v 1.75.2.8 2002/03/06 01:07:09 dillon Exp $ 65 * $DragonFly: src/sys/vm/vm_page.h,v 1.28 2008/05/09 07:24:48 dillon Exp $ 66 */ 67 68 /* 69 * Resident memory system definitions. 70 */ 71 72 #ifndef _VM_VM_PAGE_H_ 73 #define _VM_VM_PAGE_H_ 74 75 #if !defined(KLD_MODULE) && defined(_KERNEL) 76 #include "opt_vmpage.h" 77 #endif 78 79 #ifndef _SYS_TYPES_H_ 80 #include <sys/types.h> 81 #endif 82 #ifndef _SYS_TREE_H_ 83 #include <sys/tree.h> 84 #endif 85 #ifndef _MACHINE_PMAP_H_ 86 #include <machine/pmap.h> 87 #endif 88 #ifndef _VM_PMAP_H_ 89 #include <vm/pmap.h> 90 #endif 91 #ifndef _MACHINE_ATOMIC_H_ 92 #include <machine/atomic.h> 93 #endif 94 95 #ifdef _KERNEL 96 97 #ifndef _SYS_SYSTM_H_ 98 #include <sys/systm.h> 99 #endif 100 #ifndef _SYS_THREAD2_H_ 101 #include <sys/thread2.h> 102 #endif 103 104 #endif 105 106 typedef enum vm_page_event { VMEVENT_NONE, VMEVENT_COW } vm_page_event_t; 107 108 struct vm_page_action { 109 LIST_ENTRY(vm_page_action) entry; 110 vm_page_event_t event; 111 void (*func)(struct vm_page *, 112 struct vm_page_action *); 113 void *data; 114 }; 115 116 typedef struct vm_page_action *vm_page_action_t; 117 118 /* 119 * Management of resident (logical) pages. 120 * 121 * A small structure is kept for each resident 122 * page, indexed by page number. Each structure 123 * is an element of several lists: 124 * 125 * A hash table bucket used to quickly 126 * perform object/offset lookups 127 * 128 * A list of all pages for a given object, 129 * so they can be quickly deactivated at 130 * time of deallocation. 131 * 132 * An ordered list of pages due for pageout. 133 * 134 * In addition, the structure contains the object 135 * and offset to which this page belongs (for pageout), 136 * and sundry status bits. 137 * 138 * Fields in this structure are locked either by the lock on the 139 * object that the page belongs to (O) or by the lock on the page 140 * queues (P). 141 * 142 * The 'valid' and 'dirty' fields are distinct. A page may have dirty 143 * bits set without having associated valid bits set. This is used by 144 * NFS to implement piecemeal writes. 145 */ 146 147 TAILQ_HEAD(pglist, vm_page); 148 149 struct msf_buf; 150 struct vm_object; 151 152 int rb_vm_page_compare(struct vm_page *, struct vm_page *); 153 154 struct vm_page_rb_tree; 155 RB_PROTOTYPE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare, vm_pindex_t); 156 157 struct vm_page { 158 TAILQ_ENTRY(vm_page) pageq; /* vm_page_queues[] list (P) */ 159 RB_ENTRY(vm_page) rb_entry; /* Red-Black tree based at object */ 160 161 struct vm_object *object; /* which object am I in (O,P)*/ 162 vm_pindex_t pindex; /* offset into object (O,P) */ 163 vm_paddr_t phys_addr; /* physical address of page */ 164 struct md_page md; /* machine dependant stuff */ 165 u_short queue; /* page queue index */ 166 u_short flags; /* see below */ 167 u_short pc; /* page color */ 168 u_char act_count; /* page usage count */ 169 u_char busy; /* page busy count */ 170 u_int wire_count; /* wired down maps refs (P) */ 171 int hold_count; /* page hold count */ 172 173 /* 174 * NOTE that these must support one bit per DEV_BSIZE in a page!!! 175 * so, on normal X86 kernels, they must be at least 8 bits wide. 176 */ 177 #if PAGE_SIZE == 4096 178 u_char valid; /* map of valid DEV_BSIZE chunks */ 179 u_char dirty; /* map of dirty DEV_BSIZE chunks */ 180 #elif PAGE_SIZE == 8192 181 u_short valid; /* map of valid DEV_BSIZE chunks */ 182 u_short dirty; /* map of dirty DEV_BSIZE chunks */ 183 #endif 184 struct msf_buf *msf_hint; /* first page of an msfbuf map */ 185 LIST_HEAD(,vm_page_action) action_list; 186 }; 187 188 #ifndef __VM_PAGE_T_DEFINED__ 189 #define __VM_PAGE_T_DEFINED__ 190 typedef struct vm_page *vm_page_t; 191 #endif 192 193 /* 194 * note: currently use SWAPBLK_NONE as an absolute value rather then 195 * a flag bit. 196 */ 197 #define SWAPBLK_MASK ((daddr_t)((u_daddr_t)-1 >> 1)) /* mask */ 198 #define SWAPBLK_NONE ((daddr_t)((u_daddr_t)SWAPBLK_MASK + 1))/* flag */ 199 200 /* 201 * Page coloring parameters. We default to a middle of the road optimization. 202 * Larger selections would not really hurt us but if a machine does not have 203 * a lot of memory it could cause vm_page_alloc() to eat more cpu cycles 204 * looking for free pages. 205 * 206 * Page coloring cannot be disabled. Modules do not have access to most PQ 207 * constants because they can change between builds. 208 */ 209 #if defined(_KERNEL) && !defined(KLD_MODULE) 210 211 #if !defined(PQ_CACHESIZE) 212 #define PQ_CACHESIZE 256 /* max is 1024 (MB) */ 213 #endif 214 215 #if PQ_CACHESIZE >= 1024 216 #define PQ_PRIME1 31 /* Prime number somewhat less than PQ_HASH_SIZE */ 217 #define PQ_PRIME2 23 /* Prime number somewhat less than PQ_HASH_SIZE */ 218 #define PQ_L2_SIZE 256 /* A number of colors opt for 1M cache */ 219 220 #elif PQ_CACHESIZE >= 512 221 #define PQ_PRIME1 31 /* Prime number somewhat less than PQ_HASH_SIZE */ 222 #define PQ_PRIME2 23 /* Prime number somewhat less than PQ_HASH_SIZE */ 223 #define PQ_L2_SIZE 128 /* A number of colors opt for 512K cache */ 224 225 #elif PQ_CACHESIZE >= 256 226 #define PQ_PRIME1 13 /* Prime number somewhat less than PQ_HASH_SIZE */ 227 #define PQ_PRIME2 7 /* Prime number somewhat less than PQ_HASH_SIZE */ 228 #define PQ_L2_SIZE 64 /* A number of colors opt for 256K cache */ 229 230 #elif PQ_CACHESIZE >= 128 231 #define PQ_PRIME1 9 /* Produces a good PQ_L2_SIZE/3 + PQ_PRIME1 */ 232 #define PQ_PRIME2 5 /* Prime number somewhat less than PQ_HASH_SIZE */ 233 #define PQ_L2_SIZE 32 /* A number of colors opt for 128k cache */ 234 235 #else 236 #define PQ_PRIME1 5 /* Prime number somewhat less than PQ_HASH_SIZE */ 237 #define PQ_PRIME2 3 /* Prime number somewhat less than PQ_HASH_SIZE */ 238 #define PQ_L2_SIZE 16 /* A reasonable number of colors (opt for 64K cache) */ 239 240 #endif 241 242 #define PQ_L2_MASK (PQ_L2_SIZE - 1) 243 244 #endif /* KERNEL && !KLD_MODULE */ 245 246 /* 247 * 248 * The queue array is always based on PQ_MAXL2_SIZE regardless of the actual 249 * cache size chosen in order to present a uniform interface for modules. 250 */ 251 #define PQ_MAXL2_SIZE 256 /* fixed maximum (in pages) / module compat */ 252 253 #if PQ_L2_SIZE > PQ_MAXL2_SIZE 254 #error "Illegal PQ_L2_SIZE" 255 #endif 256 257 #define PQ_NONE 0 258 #define PQ_FREE 1 259 #define PQ_INACTIVE (1 + 1*PQ_MAXL2_SIZE) 260 #define PQ_ACTIVE (2 + 1*PQ_MAXL2_SIZE) 261 #define PQ_CACHE (3 + 1*PQ_MAXL2_SIZE) 262 #define PQ_HOLD (3 + 2*PQ_MAXL2_SIZE) 263 #define PQ_COUNT (4 + 2*PQ_MAXL2_SIZE) 264 265 /* 266 * Scan support 267 */ 268 struct vm_map; 269 270 struct rb_vm_page_scan_info { 271 vm_pindex_t start_pindex; 272 vm_pindex_t end_pindex; 273 int limit; 274 int desired; 275 int error; 276 int pagerflags; 277 vm_offset_t addr; 278 vm_pindex_t backing_offset_index; 279 struct vm_object *object; 280 struct vm_object *backing_object; 281 struct vm_page *mpte; 282 struct pmap *pmap; 283 struct vm_map *map; 284 }; 285 286 int rb_vm_page_scancmp(struct vm_page *, void *); 287 288 struct vpgqueues { 289 struct pglist pl; 290 int *cnt; 291 int lcnt; 292 int flipflop; /* probably not the best place */ 293 }; 294 295 extern struct vpgqueues vm_page_queues[PQ_COUNT]; 296 297 /* 298 * These are the flags defined for vm_page. 299 * 300 * PG_UNMANAGED (used by OBJT_PHYS) indicates that the page is 301 * not under PV management but otherwise should be treated as a 302 * normal page. Pages not under PV management cannot be paged out 303 * via the object/vm_page_t because there is no knowledge of their 304 * pte mappings, nor can they be removed from their objects via 305 * the object, and such pages are also not on any PQ queue. The 306 * PG_MAPPED and PG_WRITEABLE flags are not applicable. 307 * 308 * PG_MAPPED only applies to managed pages, indicating whether the page 309 * is mapped onto one or more pmaps. A page might still be mapped to 310 * special pmaps in an unmanaged fashion, for example when mapped into a 311 * buffer cache buffer, without setting PG_MAPPED. 312 * 313 * PG_WRITEABLE indicates that there may be a writeable managed pmap entry 314 * somewhere, and that the page can be dirtied by hardware at any time 315 * and may have to be tested for that. The modified bit in unmanaged 316 * mappings or in the special clean map is not tested. 317 */ 318 #define PG_BUSY 0x0001 /* page is in transit (O) */ 319 #define PG_WANTED 0x0002 /* someone is waiting for page (O) */ 320 #define PG_WINATCFLS 0x0004 /* flush dirty page on inactive q */ 321 #define PG_FICTITIOUS 0x0008 /* physical page doesn't exist (O) */ 322 #define PG_WRITEABLE 0x0010 /* page is writeable */ 323 #define PG_MAPPED 0x0020 /* page is mapped (managed) */ 324 #define PG_ZERO 0x0040 /* page is zeroed */ 325 #define PG_REFERENCED 0x0080 /* page has been referenced */ 326 #define PG_CLEANCHK 0x0100 /* page will be checked for cleaning */ 327 #define PG_SWAPINPROG 0x0200 /* swap I/O in progress on page */ 328 #define PG_NOSYNC 0x0400 /* do not collect for syncer */ 329 #define PG_UNMANAGED 0x0800 /* No PV management for page */ 330 #define PG_MARKER 0x1000 /* special queue marker page */ 331 332 /* 333 * Misc constants. 334 */ 335 336 #define ACT_DECLINE 1 337 #define ACT_ADVANCE 3 338 #define ACT_INIT 5 339 #define ACT_MAX 64 340 341 #ifdef _KERNEL 342 /* 343 * Each pageable resident page falls into one of four lists: 344 * 345 * free 346 * Available for allocation now. 347 * 348 * The following are all LRU sorted: 349 * 350 * cache 351 * Almost available for allocation. Still in an 352 * object, but clean and immediately freeable at 353 * non-interrupt times. 354 * 355 * inactive 356 * Low activity, candidates for reclamation. 357 * This is the list of pages that should be 358 * paged out next. 359 * 360 * active 361 * Pages that are "active" i.e. they have been 362 * recently referenced. 363 * 364 * zero 365 * Pages that are really free and have been pre-zeroed 366 * 367 */ 368 369 extern int vm_page_zero_count; 370 extern struct vm_page *vm_page_array; /* First resident page in table */ 371 extern int vm_page_array_size; /* number of vm_page_t's */ 372 extern long first_page; /* first physical page number */ 373 374 #define VM_PAGE_TO_PHYS(entry) \ 375 ((entry)->phys_addr) 376 377 #define PHYS_TO_VM_PAGE(pa) \ 378 (&vm_page_array[atop(pa) - first_page]) 379 380 /* 381 * Functions implemented as macros 382 */ 383 384 static __inline void 385 vm_page_flag_set(vm_page_t m, unsigned int bits) 386 { 387 atomic_set_short(&(m)->flags, bits); 388 } 389 390 static __inline void 391 vm_page_flag_clear(vm_page_t m, unsigned int bits) 392 { 393 atomic_clear_short(&(m)->flags, bits); 394 } 395 396 static __inline void 397 vm_page_busy(vm_page_t m) 398 { 399 KASSERT((m->flags & PG_BUSY) == 0, 400 ("vm_page_busy: page already busy!!!")); 401 vm_page_flag_set(m, PG_BUSY); 402 } 403 404 /* 405 * vm_page_flash: 406 * 407 * wakeup anyone waiting for the page. 408 */ 409 410 static __inline void 411 vm_page_flash(vm_page_t m) 412 { 413 if (m->flags & PG_WANTED) { 414 vm_page_flag_clear(m, PG_WANTED); 415 wakeup(m); 416 } 417 } 418 419 /* 420 * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This 421 * is typically the last call you make on a page before moving onto 422 * other things. 423 */ 424 static __inline void 425 vm_page_wakeup(vm_page_t m) 426 { 427 KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!")); 428 vm_page_flag_clear(m, PG_BUSY); 429 vm_page_flash(m); 430 } 431 432 /* 433 * These routines manipulate the 'soft busy' count for a page. A soft busy 434 * is almost like PG_BUSY except that it allows certain compatible operations 435 * to occur on the page while it is busy. For example, a page undergoing a 436 * write can still be mapped read-only. 437 */ 438 static __inline void 439 vm_page_io_start(vm_page_t m) 440 { 441 atomic_add_char(&(m)->busy, 1); 442 } 443 444 static __inline void 445 vm_page_io_finish(vm_page_t m) 446 { 447 atomic_subtract_char(&m->busy, 1); 448 if (m->busy == 0) 449 vm_page_flash(m); 450 } 451 452 453 #if PAGE_SIZE == 4096 454 #define VM_PAGE_BITS_ALL 0xff 455 #endif 456 457 #if PAGE_SIZE == 8192 458 #define VM_PAGE_BITS_ALL 0xffff 459 #endif 460 461 /* 462 * Note: the code will always use nominally free pages from the free list 463 * before trying other flag-specified sources. 464 * 465 * At least one of VM_ALLOC_NORMAL|VM_ALLOC_SYSTEM|VM_ALLOC_INTERRUPT 466 * must be specified. VM_ALLOC_RETRY may only be specified if VM_ALLOC_NORMAL 467 * is also specified. 468 */ 469 #define VM_ALLOC_NORMAL 0x01 /* ok to use cache pages */ 470 #define VM_ALLOC_SYSTEM 0x02 /* ok to exhaust most of free list */ 471 #define VM_ALLOC_INTERRUPT 0x04 /* ok to exhaust entire free list */ 472 #define VM_ALLOC_ZERO 0x08 /* req pre-zero'd memory if avail */ 473 #define VM_ALLOC_RETRY 0x80 /* indefinite block (vm_page_grab()) */ 474 475 void vm_page_unhold(vm_page_t mem); 476 void vm_page_activate (vm_page_t); 477 vm_page_t vm_page_alloc (struct vm_object *, vm_pindex_t, int); 478 vm_page_t vm_page_grab (struct vm_object *, vm_pindex_t, int); 479 void vm_page_cache (vm_page_t); 480 int vm_page_try_to_cache (vm_page_t); 481 int vm_page_try_to_free (vm_page_t); 482 void vm_page_dontneed (vm_page_t); 483 void vm_page_deactivate (vm_page_t); 484 void vm_page_insert (vm_page_t, struct vm_object *, vm_pindex_t); 485 vm_page_t vm_page_lookup (struct vm_object *, vm_pindex_t); 486 void vm_page_remove (vm_page_t); 487 void vm_page_rename (vm_page_t, struct vm_object *, vm_pindex_t); 488 vm_offset_t vm_page_startup (vm_offset_t); 489 vm_page_t vm_add_new_page (vm_paddr_t pa); 490 void vm_page_unmanage (vm_page_t); 491 void vm_page_unwire (vm_page_t, int); 492 void vm_page_wire (vm_page_t); 493 void vm_page_unqueue (vm_page_t); 494 void vm_page_unqueue_nowakeup (vm_page_t); 495 void vm_page_set_validclean (vm_page_t, int, int); 496 void vm_page_set_dirty (vm_page_t, int, int); 497 void vm_page_clear_dirty (vm_page_t, int, int); 498 void vm_page_set_invalid (vm_page_t, int, int); 499 int vm_page_is_valid (vm_page_t, int, int); 500 void vm_page_test_dirty (vm_page_t); 501 int vm_page_bits (int, int); 502 vm_page_t vm_page_list_find(int basequeue, int index, boolean_t prefer_zero); 503 void vm_page_zero_invalid(vm_page_t m, boolean_t setvalid); 504 void vm_page_free_toq(vm_page_t m); 505 vm_offset_t vm_contig_pg_kmap(int, u_long, vm_map_t, int); 506 void vm_contig_pg_free(int, u_long); 507 void vm_page_event_internal(vm_page_t, vm_page_event_t); 508 void vm_page_dirty(vm_page_t m); 509 510 /* 511 * Holding a page keeps it from being reused. Other parts of the system 512 * can still disassociate the page from its current object and free it, or 513 * perform read or write I/O on it and/or otherwise manipulate the page, 514 * but if the page is held the VM system will leave the page and its data 515 * intact and not reuse the page for other purposes until the last hold 516 * reference is released. (see vm_page_wire() if you want to prevent the 517 * page from being disassociated from its object too). 518 * 519 * This routine must be called while at splvm() or better. 520 * 521 * The caller must still validate the contents of the page and, if necessary, 522 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete 523 * before manipulating the page. 524 */ 525 static __inline void 526 vm_page_hold(vm_page_t mem) 527 { 528 mem->hold_count++; 529 } 530 531 /* 532 * Reduce the protection of a page. This routine never raises the 533 * protection and therefore can be safely called if the page is already 534 * at VM_PROT_NONE (it will be a NOP effectively ). 535 * 536 * VM_PROT_NONE will remove all user mappings of a page. This is often 537 * necessary when a page changes state (for example, turns into a copy-on-write 538 * page or needs to be frozen for write I/O) in order to force a fault, or 539 * to force a page's dirty bits to be synchronized and avoid hardware 540 * (modified/accessed) bit update races with pmap changes. 541 * 542 * Since 'prot' is usually a constant, this inline usually winds up optimizing 543 * out the primary conditional. 544 * 545 * WARNING: VM_PROT_NONE can block, but will loop until all mappings have 546 * been cleared. Callers should be aware that other page related elements 547 * might have changed, however. 548 */ 549 static __inline void 550 vm_page_protect(vm_page_t mem, int prot) 551 { 552 if (prot == VM_PROT_NONE) { 553 if (mem->flags & (PG_WRITEABLE|PG_MAPPED)) { 554 pmap_page_protect(mem, VM_PROT_NONE); 555 /* PG_WRITEABLE & PG_MAPPED cleared by call */ 556 } 557 } else if ((prot == VM_PROT_READ) && (mem->flags & PG_WRITEABLE)) { 558 pmap_page_protect(mem, VM_PROT_READ); 559 /* PG_WRITEABLE cleared by call */ 560 } 561 } 562 563 /* 564 * Zero-fill the specified page. The entire contents of the page will be 565 * zero'd out. 566 */ 567 static __inline boolean_t 568 vm_page_zero_fill(vm_page_t m) 569 { 570 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 571 return (TRUE); 572 } 573 574 /* 575 * Copy the contents of src_m to dest_m. The pages must be stable but spl 576 * and other protections depend on context. 577 */ 578 static __inline void 579 vm_page_copy(vm_page_t src_m, vm_page_t dest_m) 580 { 581 pmap_copy_page(VM_PAGE_TO_PHYS(src_m), VM_PAGE_TO_PHYS(dest_m)); 582 dest_m->valid = VM_PAGE_BITS_ALL; 583 dest_m->dirty = VM_PAGE_BITS_ALL; 584 } 585 586 /* 587 * Free a page. The page must be marked BUSY. 588 * 589 * The clearing of PG_ZERO is a temporary safety until the code can be 590 * reviewed to determine that PG_ZERO is being properly cleared on 591 * write faults or maps. PG_ZERO was previously cleared in 592 * vm_page_alloc(). 593 */ 594 static __inline void 595 vm_page_free(vm_page_t m) 596 { 597 vm_page_flag_clear(m, PG_ZERO); 598 vm_page_free_toq(m); 599 } 600 601 /* 602 * Free a page to the zerod-pages queue 603 */ 604 static __inline void 605 vm_page_free_zero(vm_page_t m) 606 { 607 vm_page_flag_set(m, PG_ZERO); 608 vm_page_free_toq(m); 609 } 610 611 /* 612 * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE) 613 * m->busy is zero. Returns TRUE if it had to sleep ( including if 614 * it almost had to sleep and made temporary spl*() mods), FALSE 615 * otherwise. 616 * 617 * This routine assumes that interrupts can only remove the busy 618 * status from a page, not set the busy status or change it from 619 * PG_BUSY to m->busy or vise versa (which would create a timing 620 * window). 621 * 622 * Note: as an inline, 'also_m_busy' is usually a constant and well 623 * optimized. 624 */ 625 static __inline int 626 vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg) 627 { 628 if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) { 629 crit_enter(); 630 if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) { 631 /* 632 * Page is busy. Wait and retry. 633 */ 634 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); 635 tsleep(m, 0, msg, 0); 636 } 637 crit_exit(); 638 return(TRUE); 639 /* not reached */ 640 } 641 return(FALSE); 642 } 643 644 /* 645 * Set page to not be dirty. Note: does not clear pmap modify bits . 646 */ 647 static __inline void 648 vm_page_undirty(vm_page_t m) 649 { 650 m->dirty = 0; 651 } 652 653 #endif /* _KERNEL */ 654 #endif /* !_VM_VM_PAGE_H_ */ 655