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 #ifdef __amd64__ 105 #include <machine/vmparam.h> 106 #endif 107 108 #endif 109 110 typedef enum vm_page_event { VMEVENT_NONE, VMEVENT_COW } vm_page_event_t; 111 112 struct vm_page_action { 113 LIST_ENTRY(vm_page_action) entry; 114 vm_page_event_t event; 115 void (*func)(struct vm_page *, 116 struct vm_page_action *); 117 void *data; 118 }; 119 120 typedef struct vm_page_action *vm_page_action_t; 121 122 /* 123 * Management of resident (logical) pages. 124 * 125 * A small structure is kept for each resident 126 * page, indexed by page number. Each structure 127 * is an element of several lists: 128 * 129 * A hash table bucket used to quickly 130 * perform object/offset lookups 131 * 132 * A list of all pages for a given object, 133 * so they can be quickly deactivated at 134 * time of deallocation. 135 * 136 * An ordered list of pages due for pageout. 137 * 138 * In addition, the structure contains the object 139 * and offset to which this page belongs (for pageout), 140 * and sundry status bits. 141 * 142 * Fields in this structure are locked either by the lock on the 143 * object that the page belongs to (O) or by the lock on the page 144 * queues (P). 145 * 146 * The 'valid' and 'dirty' fields are distinct. A page may have dirty 147 * bits set without having associated valid bits set. This is used by 148 * NFS to implement piecemeal writes. 149 */ 150 151 TAILQ_HEAD(pglist, vm_page); 152 153 struct msf_buf; 154 struct vm_object; 155 156 int rb_vm_page_compare(struct vm_page *, struct vm_page *); 157 158 struct vm_page_rb_tree; 159 RB_PROTOTYPE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare, vm_pindex_t); 160 161 struct vm_page { 162 TAILQ_ENTRY(vm_page) pageq; /* vm_page_queues[] list (P) */ 163 RB_ENTRY(vm_page) rb_entry; /* Red-Black tree based at object */ 164 165 struct vm_object *object; /* which object am I in (O,P)*/ 166 vm_pindex_t pindex; /* offset into object (O,P) */ 167 vm_paddr_t phys_addr; /* physical address of page */ 168 struct md_page md; /* machine dependant stuff */ 169 u_short queue; /* page queue index */ 170 u_short flags; /* see below */ 171 u_short pc; /* page color */ 172 u_char act_count; /* page usage count */ 173 u_char busy; /* page busy count */ 174 u_int wire_count; /* wired down maps refs (P) */ 175 int hold_count; /* page hold count */ 176 177 /* 178 * NOTE that these must support one bit per DEV_BSIZE in a page!!! 179 * so, on normal X86 kernels, they must be at least 8 bits wide. 180 */ 181 #if PAGE_SIZE == 4096 182 u_char valid; /* map of valid DEV_BSIZE chunks */ 183 u_char dirty; /* map of dirty DEV_BSIZE chunks */ 184 #elif PAGE_SIZE == 8192 185 u_short valid; /* map of valid DEV_BSIZE chunks */ 186 u_short dirty; /* map of dirty DEV_BSIZE chunks */ 187 #endif 188 struct msf_buf *msf_hint; /* first page of an msfbuf map */ 189 LIST_HEAD(,vm_page_action) action_list; 190 }; 191 192 #ifndef __VM_PAGE_T_DEFINED__ 193 #define __VM_PAGE_T_DEFINED__ 194 typedef struct vm_page *vm_page_t; 195 #endif 196 197 /* 198 * note: currently use SWAPBLK_NONE as an absolute value rather then 199 * a flag bit. 200 */ 201 #define SWAPBLK_MASK ((daddr_t)((u_daddr_t)-1 >> 1)) /* mask */ 202 #define SWAPBLK_NONE ((daddr_t)((u_daddr_t)SWAPBLK_MASK + 1))/* flag */ 203 204 /* 205 * Page coloring parameters. We default to a middle of the road optimization. 206 * Larger selections would not really hurt us but if a machine does not have 207 * a lot of memory it could cause vm_page_alloc() to eat more cpu cycles 208 * looking for free pages. 209 * 210 * Page coloring cannot be disabled. Modules do not have access to most PQ 211 * constants because they can change between builds. 212 */ 213 #if defined(_KERNEL) && !defined(KLD_MODULE) 214 215 #if !defined(PQ_CACHESIZE) 216 #define PQ_CACHESIZE 256 /* max is 1024 (MB) */ 217 #endif 218 219 #if PQ_CACHESIZE >= 1024 220 #define PQ_PRIME1 31 /* Prime number somewhat less than PQ_HASH_SIZE */ 221 #define PQ_PRIME2 23 /* Prime number somewhat less than PQ_HASH_SIZE */ 222 #define PQ_L2_SIZE 256 /* A number of colors opt for 1M cache */ 223 224 #elif PQ_CACHESIZE >= 512 225 #define PQ_PRIME1 31 /* Prime number somewhat less than PQ_HASH_SIZE */ 226 #define PQ_PRIME2 23 /* Prime number somewhat less than PQ_HASH_SIZE */ 227 #define PQ_L2_SIZE 128 /* A number of colors opt for 512K cache */ 228 229 #elif PQ_CACHESIZE >= 256 230 #define PQ_PRIME1 13 /* Prime number somewhat less than PQ_HASH_SIZE */ 231 #define PQ_PRIME2 7 /* Prime number somewhat less than PQ_HASH_SIZE */ 232 #define PQ_L2_SIZE 64 /* A number of colors opt for 256K cache */ 233 234 #elif PQ_CACHESIZE >= 128 235 #define PQ_PRIME1 9 /* Produces a good PQ_L2_SIZE/3 + PQ_PRIME1 */ 236 #define PQ_PRIME2 5 /* Prime number somewhat less than PQ_HASH_SIZE */ 237 #define PQ_L2_SIZE 32 /* A number of colors opt for 128k cache */ 238 239 #else 240 #define PQ_PRIME1 5 /* Prime number somewhat less than PQ_HASH_SIZE */ 241 #define PQ_PRIME2 3 /* Prime number somewhat less than PQ_HASH_SIZE */ 242 #define PQ_L2_SIZE 16 /* A reasonable number of colors (opt for 64K cache) */ 243 244 #endif 245 246 #define PQ_L2_MASK (PQ_L2_SIZE - 1) 247 248 #endif /* KERNEL && !KLD_MODULE */ 249 250 /* 251 * 252 * The queue array is always based on PQ_MAXL2_SIZE regardless of the actual 253 * cache size chosen in order to present a uniform interface for modules. 254 */ 255 #define PQ_MAXL2_SIZE 256 /* fixed maximum (in pages) / module compat */ 256 257 #if PQ_L2_SIZE > PQ_MAXL2_SIZE 258 #error "Illegal PQ_L2_SIZE" 259 #endif 260 261 #define PQ_NONE 0 262 #define PQ_FREE 1 263 #define PQ_INACTIVE (1 + 1*PQ_MAXL2_SIZE) 264 #define PQ_ACTIVE (2 + 1*PQ_MAXL2_SIZE) 265 #define PQ_CACHE (3 + 1*PQ_MAXL2_SIZE) 266 #define PQ_HOLD (3 + 2*PQ_MAXL2_SIZE) 267 #define PQ_COUNT (4 + 2*PQ_MAXL2_SIZE) 268 269 /* 270 * Scan support 271 */ 272 struct vm_map; 273 274 struct rb_vm_page_scan_info { 275 vm_pindex_t start_pindex; 276 vm_pindex_t end_pindex; 277 int limit; 278 int desired; 279 int error; 280 int pagerflags; 281 vm_offset_t addr; 282 vm_pindex_t backing_offset_index; 283 struct vm_object *object; 284 struct vm_object *backing_object; 285 struct vm_page *mpte; 286 struct pmap *pmap; 287 struct vm_map *map; 288 }; 289 290 int rb_vm_page_scancmp(struct vm_page *, void *); 291 292 struct vpgqueues { 293 struct pglist pl; 294 int *cnt; 295 int lcnt; 296 int flipflop; /* probably not the best place */ 297 }; 298 299 extern struct vpgqueues vm_page_queues[PQ_COUNT]; 300 301 /* 302 * These are the flags defined for vm_page. 303 * 304 * PG_UNMANAGED (used by OBJT_PHYS) indicates that the page is 305 * not under PV management but otherwise should be treated as a 306 * normal page. Pages not under PV management cannot be paged out 307 * via the object/vm_page_t because there is no knowledge of their 308 * pte mappings, nor can they be removed from their objects via 309 * the object, and such pages are also not on any PQ queue. The 310 * PG_MAPPED and PG_WRITEABLE flags are not applicable. 311 * 312 * PG_MAPPED only applies to managed pages, indicating whether the page 313 * is mapped onto one or more pmaps. A page might still be mapped to 314 * special pmaps in an unmanaged fashion, for example when mapped into a 315 * buffer cache buffer, without setting PG_MAPPED. 316 * 317 * PG_WRITEABLE indicates that there may be a writeable managed pmap entry 318 * somewhere, and that the page can be dirtied by hardware at any time 319 * and may have to be tested for that. The modified bit in unmanaged 320 * mappings or in the special clean map is not tested. 321 */ 322 #define PG_BUSY 0x0001 /* page is in transit (O) */ 323 #define PG_WANTED 0x0002 /* someone is waiting for page (O) */ 324 #define PG_WINATCFLS 0x0004 /* flush dirty page on inactive q */ 325 #define PG_FICTITIOUS 0x0008 /* physical page doesn't exist (O) */ 326 #define PG_WRITEABLE 0x0010 /* page is writeable */ 327 #define PG_MAPPED 0x0020 /* page is mapped (managed) */ 328 #define PG_ZERO 0x0040 /* page is zeroed */ 329 #define PG_REFERENCED 0x0080 /* page has been referenced */ 330 #define PG_CLEANCHK 0x0100 /* page will be checked for cleaning */ 331 #define PG_SWAPINPROG 0x0200 /* swap I/O in progress on page */ 332 #define PG_NOSYNC 0x0400 /* do not collect for syncer */ 333 #define PG_UNMANAGED 0x0800 /* No PV management for page */ 334 #define PG_MARKER 0x1000 /* special queue marker page */ 335 336 /* 337 * Misc constants. 338 */ 339 340 #define ACT_DECLINE 1 341 #define ACT_ADVANCE 3 342 #define ACT_INIT 5 343 #define ACT_MAX 64 344 345 #ifdef _KERNEL 346 /* 347 * Each pageable resident page falls into one of four lists: 348 * 349 * free 350 * Available for allocation now. 351 * 352 * The following are all LRU sorted: 353 * 354 * cache 355 * Almost available for allocation. Still in an 356 * object, but clean and immediately freeable at 357 * non-interrupt times. 358 * 359 * inactive 360 * Low activity, candidates for reclamation. 361 * This is the list of pages that should be 362 * paged out next. 363 * 364 * active 365 * Pages that are "active" i.e. they have been 366 * recently referenced. 367 * 368 * zero 369 * Pages that are really free and have been pre-zeroed 370 * 371 */ 372 373 extern int vm_page_zero_count; 374 extern struct vm_page *vm_page_array; /* First resident page in table */ 375 extern int vm_page_array_size; /* number of vm_page_t's */ 376 extern long first_page; /* first physical page number */ 377 378 #define VM_PAGE_TO_PHYS(entry) \ 379 ((entry)->phys_addr) 380 381 #define PHYS_TO_VM_PAGE(pa) \ 382 (&vm_page_array[atop(pa) - first_page]) 383 384 /* 385 * Functions implemented as macros 386 */ 387 388 static __inline void 389 vm_page_flag_set(vm_page_t m, unsigned int bits) 390 { 391 atomic_set_short(&(m)->flags, bits); 392 } 393 394 static __inline void 395 vm_page_flag_clear(vm_page_t m, unsigned int bits) 396 { 397 atomic_clear_short(&(m)->flags, bits); 398 } 399 400 static __inline void 401 vm_page_busy(vm_page_t m) 402 { 403 KASSERT((m->flags & PG_BUSY) == 0, 404 ("vm_page_busy: page already busy!!!")); 405 vm_page_flag_set(m, PG_BUSY); 406 } 407 408 /* 409 * vm_page_flash: 410 * 411 * wakeup anyone waiting for the page. 412 */ 413 414 static __inline void 415 vm_page_flash(vm_page_t m) 416 { 417 if (m->flags & PG_WANTED) { 418 vm_page_flag_clear(m, PG_WANTED); 419 wakeup(m); 420 } 421 } 422 423 /* 424 * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This 425 * is typically the last call you make on a page before moving onto 426 * other things. 427 */ 428 static __inline void 429 vm_page_wakeup(vm_page_t m) 430 { 431 KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!")); 432 vm_page_flag_clear(m, PG_BUSY); 433 vm_page_flash(m); 434 } 435 436 /* 437 * These routines manipulate the 'soft busy' count for a page. A soft busy 438 * is almost like PG_BUSY except that it allows certain compatible operations 439 * to occur on the page while it is busy. For example, a page undergoing a 440 * write can still be mapped read-only. 441 */ 442 static __inline void 443 vm_page_io_start(vm_page_t m) 444 { 445 atomic_add_char(&(m)->busy, 1); 446 } 447 448 static __inline void 449 vm_page_io_finish(vm_page_t m) 450 { 451 atomic_subtract_char(&m->busy, 1); 452 if (m->busy == 0) 453 vm_page_flash(m); 454 } 455 456 457 #if PAGE_SIZE == 4096 458 #define VM_PAGE_BITS_ALL 0xff 459 #endif 460 461 #if PAGE_SIZE == 8192 462 #define VM_PAGE_BITS_ALL 0xffff 463 #endif 464 465 /* 466 * Note: the code will always use nominally free pages from the free list 467 * before trying other flag-specified sources. 468 * 469 * At least one of VM_ALLOC_NORMAL|VM_ALLOC_SYSTEM|VM_ALLOC_INTERRUPT 470 * must be specified. VM_ALLOC_RETRY may only be specified if VM_ALLOC_NORMAL 471 * is also specified. 472 */ 473 #define VM_ALLOC_NORMAL 0x01 /* ok to use cache pages */ 474 #define VM_ALLOC_SYSTEM 0x02 /* ok to exhaust most of free list */ 475 #define VM_ALLOC_INTERRUPT 0x04 /* ok to exhaust entire free list */ 476 #define VM_ALLOC_ZERO 0x08 /* req pre-zero'd memory if avail */ 477 #define VM_ALLOC_RETRY 0x80 /* indefinite block (vm_page_grab()) */ 478 479 void vm_page_unhold(vm_page_t mem); 480 void vm_page_activate (vm_page_t); 481 vm_page_t vm_page_alloc (struct vm_object *, vm_pindex_t, int); 482 vm_page_t vm_page_grab (struct vm_object *, vm_pindex_t, int); 483 void vm_page_cache (vm_page_t); 484 int vm_page_try_to_cache (vm_page_t); 485 int vm_page_try_to_free (vm_page_t); 486 void vm_page_dontneed (vm_page_t); 487 void vm_page_deactivate (vm_page_t); 488 void vm_page_insert (vm_page_t, struct vm_object *, vm_pindex_t); 489 vm_page_t vm_page_lookup (struct vm_object *, vm_pindex_t); 490 void vm_page_remove (vm_page_t); 491 void vm_page_rename (vm_page_t, struct vm_object *, vm_pindex_t); 492 vm_offset_t vm_page_startup (vm_offset_t); 493 vm_page_t vm_add_new_page (vm_paddr_t pa); 494 void vm_page_unmanage (vm_page_t); 495 void vm_page_unwire (vm_page_t, int); 496 void vm_page_wire (vm_page_t); 497 void vm_page_unqueue (vm_page_t); 498 void vm_page_unqueue_nowakeup (vm_page_t); 499 void vm_page_set_validclean (vm_page_t, int, int); 500 void vm_page_set_valid (vm_page_t, int, int); 501 void vm_page_set_dirty (vm_page_t, int, int); 502 void vm_page_clear_dirty (vm_page_t, int, int); 503 void vm_page_set_invalid (vm_page_t, int, int); 504 int vm_page_is_valid (vm_page_t, int, int); 505 void vm_page_test_dirty (vm_page_t); 506 int vm_page_bits (int, int); 507 vm_page_t vm_page_list_find(int basequeue, int index, boolean_t prefer_zero); 508 void vm_page_zero_invalid(vm_page_t m, boolean_t setvalid); 509 void vm_page_free_toq(vm_page_t m); 510 vm_offset_t vm_contig_pg_kmap(int, u_long, vm_map_t, int); 511 void vm_contig_pg_free(int, u_long); 512 void vm_page_event_internal(vm_page_t, vm_page_event_t); 513 void vm_page_dirty(vm_page_t m); 514 515 /* 516 * Holding a page keeps it from being reused. Other parts of the system 517 * can still disassociate the page from its current object and free it, or 518 * perform read or write I/O on it and/or otherwise manipulate the page, 519 * but if the page is held the VM system will leave the page and its data 520 * intact and not reuse the page for other purposes until the last hold 521 * reference is released. (see vm_page_wire() if you want to prevent the 522 * page from being disassociated from its object too). 523 * 524 * This routine must be called while at splvm() or better. 525 * 526 * The caller must still validate the contents of the page and, if necessary, 527 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete 528 * before manipulating the page. 529 */ 530 static __inline void 531 vm_page_hold(vm_page_t mem) 532 { 533 mem->hold_count++; 534 } 535 536 /* 537 * Reduce the protection of a page. This routine never raises the 538 * protection and therefore can be safely called if the page is already 539 * at VM_PROT_NONE (it will be a NOP effectively ). 540 * 541 * VM_PROT_NONE will remove all user mappings of a page. This is often 542 * necessary when a page changes state (for example, turns into a copy-on-write 543 * page or needs to be frozen for write I/O) in order to force a fault, or 544 * to force a page's dirty bits to be synchronized and avoid hardware 545 * (modified/accessed) bit update races with pmap changes. 546 * 547 * Since 'prot' is usually a constant, this inline usually winds up optimizing 548 * out the primary conditional. 549 * 550 * WARNING: VM_PROT_NONE can block, but will loop until all mappings have 551 * been cleared. Callers should be aware that other page related elements 552 * might have changed, however. 553 */ 554 static __inline void 555 vm_page_protect(vm_page_t mem, int prot) 556 { 557 if (prot == VM_PROT_NONE) { 558 if (mem->flags & (PG_WRITEABLE|PG_MAPPED)) { 559 pmap_page_protect(mem, VM_PROT_NONE); 560 /* PG_WRITEABLE & PG_MAPPED cleared by call */ 561 } 562 } else if ((prot == VM_PROT_READ) && (mem->flags & PG_WRITEABLE)) { 563 pmap_page_protect(mem, VM_PROT_READ); 564 /* PG_WRITEABLE cleared by call */ 565 } 566 } 567 568 /* 569 * Zero-fill the specified page. The entire contents of the page will be 570 * zero'd out. 571 */ 572 static __inline boolean_t 573 vm_page_zero_fill(vm_page_t m) 574 { 575 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 576 return (TRUE); 577 } 578 579 /* 580 * Copy the contents of src_m to dest_m. The pages must be stable but spl 581 * and other protections depend on context. 582 */ 583 static __inline void 584 vm_page_copy(vm_page_t src_m, vm_page_t dest_m) 585 { 586 pmap_copy_page(VM_PAGE_TO_PHYS(src_m), VM_PAGE_TO_PHYS(dest_m)); 587 dest_m->valid = VM_PAGE_BITS_ALL; 588 dest_m->dirty = VM_PAGE_BITS_ALL; 589 } 590 591 /* 592 * Free a page. The page must be marked BUSY. 593 * 594 * The clearing of PG_ZERO is a temporary safety until the code can be 595 * reviewed to determine that PG_ZERO is being properly cleared on 596 * write faults or maps. PG_ZERO was previously cleared in 597 * vm_page_alloc(). 598 */ 599 static __inline void 600 vm_page_free(vm_page_t m) 601 { 602 vm_page_flag_clear(m, PG_ZERO); 603 vm_page_free_toq(m); 604 } 605 606 /* 607 * Free a page to the zerod-pages queue 608 */ 609 static __inline void 610 vm_page_free_zero(vm_page_t m) 611 { 612 #ifdef __amd64__ 613 /* JG DEBUG64 We check if the page is really zeroed. */ 614 char *p = (char *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m)); 615 int i; 616 617 for (i = 0; i < PAGE_SIZE; i++) { 618 if (p[i] != 0) { 619 panic("non-zero page in vm_page_free_zero()"); 620 } 621 } 622 623 #endif 624 vm_page_flag_set(m, PG_ZERO); 625 vm_page_free_toq(m); 626 } 627 628 /* 629 * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE) 630 * m->busy is zero. Returns TRUE if it had to sleep ( including if 631 * it almost had to sleep and made temporary spl*() mods), FALSE 632 * otherwise. 633 * 634 * This routine assumes that interrupts can only remove the busy 635 * status from a page, not set the busy status or change it from 636 * PG_BUSY to m->busy or vise versa (which would create a timing 637 * window). 638 * 639 * Note: as an inline, 'also_m_busy' is usually a constant and well 640 * optimized. 641 */ 642 static __inline int 643 vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg) 644 { 645 if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) { 646 crit_enter(); 647 if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) { 648 /* 649 * Page is busy. Wait and retry. 650 */ 651 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); 652 tsleep(m, 0, msg, 0); 653 } 654 crit_exit(); 655 return(TRUE); 656 /* not reached */ 657 } 658 return(FALSE); 659 } 660 661 /* 662 * Set page to not be dirty. Note: does not clear pmap modify bits . 663 */ 664 static __inline void 665 vm_page_undirty(vm_page_t m) 666 { 667 m->dirty = 0; 668 } 669 670 #endif /* _KERNEL */ 671 #endif /* !_VM_VM_PAGE_H_ */ 672