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 __x86_64__ 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 vm_object; 154 155 int rb_vm_page_compare(struct vm_page *, struct vm_page *); 156 157 struct vm_page_rb_tree; 158 RB_PROTOTYPE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare, vm_pindex_t); 159 160 struct vm_page { 161 TAILQ_ENTRY(vm_page) pageq; /* vm_page_queues[] list (P) */ 162 RB_ENTRY(vm_page) rb_entry; /* Red-Black tree based at object */ 163 164 struct vm_object *object; /* which object am I in (O,P)*/ 165 vm_pindex_t pindex; /* offset into object (O,P) */ 166 vm_paddr_t phys_addr; /* physical address of page */ 167 struct md_page md; /* machine dependant stuff */ 168 u_short queue; /* page queue index */ 169 u_short flags; /* see below */ 170 u_short pc; /* page color */ 171 u_char act_count; /* page usage count */ 172 u_char busy; /* page busy count */ 173 u_int wire_count; /* wired down maps refs (P) */ 174 int hold_count; /* page hold count */ 175 176 /* 177 * NOTE that these must support one bit per DEV_BSIZE in a page!!! 178 * so, on normal X86 kernels, they must be at least 8 bits wide. 179 */ 180 #if PAGE_SIZE == 4096 181 u_char valid; /* map of valid DEV_BSIZE chunks */ 182 u_char dirty; /* map of dirty DEV_BSIZE chunks */ 183 #elif PAGE_SIZE == 8192 184 u_short valid; /* map of valid DEV_BSIZE chunks */ 185 u_short dirty; /* map of dirty DEV_BSIZE chunks */ 186 #endif 187 LIST_HEAD(,vm_page_action) action_list; 188 }; 189 190 #ifndef __VM_PAGE_T_DEFINED__ 191 #define __VM_PAGE_T_DEFINED__ 192 typedef struct vm_page *vm_page_t; 193 #endif 194 195 /* 196 * note: currently use SWAPBLK_NONE as an absolute value rather then 197 * a flag bit. 198 */ 199 #define SWAPBLK_MASK ((daddr_t)((u_daddr_t)-1 >> 1)) /* mask */ 200 #define SWAPBLK_NONE ((daddr_t)((u_daddr_t)SWAPBLK_MASK + 1))/* flag */ 201 202 /* 203 * Page coloring parameters. We default to a middle of the road optimization. 204 * Larger selections would not really hurt us but if a machine does not have 205 * a lot of memory it could cause vm_page_alloc() to eat more cpu cycles 206 * looking for free pages. 207 * 208 * Page coloring cannot be disabled. Modules do not have access to most PQ 209 * constants because they can change between builds. 210 */ 211 #if defined(_KERNEL) && !defined(KLD_MODULE) 212 213 #if !defined(PQ_CACHESIZE) 214 #define PQ_CACHESIZE 256 /* max is 1024 (MB) */ 215 #endif 216 217 #if PQ_CACHESIZE >= 1024 218 #define PQ_PRIME1 31 /* Prime number somewhat less than PQ_HASH_SIZE */ 219 #define PQ_PRIME2 23 /* Prime number somewhat less than PQ_HASH_SIZE */ 220 #define PQ_L2_SIZE 256 /* A number of colors opt for 1M cache */ 221 222 #elif PQ_CACHESIZE >= 512 223 #define PQ_PRIME1 31 /* Prime number somewhat less than PQ_HASH_SIZE */ 224 #define PQ_PRIME2 23 /* Prime number somewhat less than PQ_HASH_SIZE */ 225 #define PQ_L2_SIZE 128 /* A number of colors opt for 512K cache */ 226 227 #elif PQ_CACHESIZE >= 256 228 #define PQ_PRIME1 13 /* Prime number somewhat less than PQ_HASH_SIZE */ 229 #define PQ_PRIME2 7 /* Prime number somewhat less than PQ_HASH_SIZE */ 230 #define PQ_L2_SIZE 64 /* A number of colors opt for 256K cache */ 231 232 #elif PQ_CACHESIZE >= 128 233 #define PQ_PRIME1 9 /* Produces a good PQ_L2_SIZE/3 + PQ_PRIME1 */ 234 #define PQ_PRIME2 5 /* Prime number somewhat less than PQ_HASH_SIZE */ 235 #define PQ_L2_SIZE 32 /* A number of colors opt for 128k cache */ 236 237 #else 238 #define PQ_PRIME1 5 /* Prime number somewhat less than PQ_HASH_SIZE */ 239 #define PQ_PRIME2 3 /* Prime number somewhat less than PQ_HASH_SIZE */ 240 #define PQ_L2_SIZE 16 /* A reasonable number of colors (opt for 64K cache) */ 241 242 #endif 243 244 #define PQ_L2_MASK (PQ_L2_SIZE - 1) 245 246 #endif /* KERNEL && !KLD_MODULE */ 247 248 /* 249 * 250 * The queue array is always based on PQ_MAXL2_SIZE regardless of the actual 251 * cache size chosen in order to present a uniform interface for modules. 252 */ 253 #define PQ_MAXL2_SIZE 256 /* fixed maximum (in pages) / module compat */ 254 255 #if PQ_L2_SIZE > PQ_MAXL2_SIZE 256 #error "Illegal PQ_L2_SIZE" 257 #endif 258 259 #define PQ_NONE 0 260 #define PQ_FREE 1 261 #define PQ_INACTIVE (1 + 1*PQ_MAXL2_SIZE) 262 #define PQ_ACTIVE (2 + 1*PQ_MAXL2_SIZE) 263 #define PQ_CACHE (3 + 1*PQ_MAXL2_SIZE) 264 #define PQ_HOLD (3 + 2*PQ_MAXL2_SIZE) 265 #define PQ_COUNT (4 + 2*PQ_MAXL2_SIZE) 266 267 /* 268 * Scan support 269 */ 270 struct vm_map; 271 272 struct rb_vm_page_scan_info { 273 vm_pindex_t start_pindex; 274 vm_pindex_t end_pindex; 275 int limit; 276 int desired; 277 int error; 278 int pagerflags; 279 vm_offset_t addr; 280 vm_pindex_t backing_offset_index; 281 struct vm_object *object; 282 struct vm_object *backing_object; 283 struct vm_page *mpte; 284 struct pmap *pmap; 285 struct vm_map *map; 286 }; 287 288 int rb_vm_page_scancmp(struct vm_page *, void *); 289 290 struct vpgqueues { 291 struct pglist pl; 292 int *cnt; 293 int lcnt; 294 int flipflop; /* probably not the best place */ 295 }; 296 297 extern struct vpgqueues vm_page_queues[PQ_COUNT]; 298 299 /* 300 * These are the flags defined for vm_page. 301 * 302 * PG_UNMANAGED (used by OBJT_PHYS) indicates that the page is 303 * not under PV management but otherwise should be treated as a 304 * normal page. Pages not under PV management cannot be paged out 305 * via the object/vm_page_t because there is no knowledge of their 306 * pte mappings, nor can they be removed from their objects via 307 * the object, and such pages are also not on any PQ queue. The 308 * PG_MAPPED and PG_WRITEABLE flags are not applicable. 309 * 310 * PG_MAPPED only applies to managed pages, indicating whether the page 311 * is mapped onto one or more pmaps. A page might still be mapped to 312 * special pmaps in an unmanaged fashion, for example when mapped into a 313 * buffer cache buffer, without setting PG_MAPPED. 314 * 315 * PG_WRITEABLE indicates that there may be a writeable managed pmap entry 316 * somewhere, and that the page can be dirtied by hardware at any time 317 * and may have to be tested for that. The modified bit in unmanaged 318 * mappings or in the special clean map is not tested. 319 * 320 * PG_SWAPPED indicates that the page is backed by a swap block. Any 321 * VM object type other than OBJT_DEFAULT can have swap-backed pages now. 322 */ 323 #define PG_BUSY 0x0001 /* page is in transit (O) */ 324 #define PG_WANTED 0x0002 /* someone is waiting for page (O) */ 325 #define PG_WINATCFLS 0x0004 /* flush dirty page on inactive q */ 326 #define PG_FICTITIOUS 0x0008 /* physical page doesn't exist (O) */ 327 #define PG_WRITEABLE 0x0010 /* page is writeable */ 328 #define PG_MAPPED 0x0020 /* page is mapped (managed) */ 329 #define PG_ZERO 0x0040 /* page is zeroed */ 330 #define PG_REFERENCED 0x0080 /* page has been referenced */ 331 #define PG_CLEANCHK 0x0100 /* page will be checked for cleaning */ 332 #define PG_SWAPINPROG 0x0200 /* swap I/O in progress on page */ 333 #define PG_NOSYNC 0x0400 /* do not collect for syncer */ 334 #define PG_UNMANAGED 0x0800 /* No PV management for page */ 335 #define PG_MARKER 0x1000 /* special queue marker page */ 336 #define PG_RAM 0x2000 /* read ahead mark */ 337 #define PG_SWAPPED 0x4000 /* backed by swap */ 338 #define PG_NOTMETA 0x8000 /* do not back with swap */ 339 /* u_short, only 16 flag bits */ 340 341 /* 342 * Misc constants. 343 */ 344 345 #define ACT_DECLINE 1 346 #define ACT_ADVANCE 3 347 #define ACT_INIT 5 348 #define ACT_MAX 64 349 350 #ifdef _KERNEL 351 /* 352 * Each pageable resident page falls into one of four lists: 353 * 354 * free 355 * Available for allocation now. 356 * 357 * The following are all LRU sorted: 358 * 359 * cache 360 * Almost available for allocation. Still in an 361 * object, but clean and immediately freeable at 362 * non-interrupt times. 363 * 364 * inactive 365 * Low activity, candidates for reclamation. 366 * This is the list of pages that should be 367 * paged out next. 368 * 369 * active 370 * Pages that are "active" i.e. they have been 371 * recently referenced. 372 * 373 * zero 374 * Pages that are really free and have been pre-zeroed 375 * 376 */ 377 378 extern int vm_page_zero_count; 379 extern struct vm_page *vm_page_array; /* First resident page in table */ 380 extern int vm_page_array_size; /* number of vm_page_t's */ 381 extern long first_page; /* first physical page number */ 382 383 #define VM_PAGE_TO_PHYS(entry) \ 384 ((entry)->phys_addr) 385 386 #define PHYS_TO_VM_PAGE(pa) \ 387 (&vm_page_array[atop(pa) - first_page]) 388 389 /* 390 * Functions implemented as macros 391 */ 392 393 static __inline void 394 vm_page_flag_set(vm_page_t m, unsigned int bits) 395 { 396 atomic_set_short(&(m)->flags, bits); 397 } 398 399 static __inline void 400 vm_page_flag_clear(vm_page_t m, unsigned int bits) 401 { 402 atomic_clear_short(&(m)->flags, bits); 403 } 404 405 static __inline void 406 vm_page_busy(vm_page_t m) 407 { 408 ASSERT_LWKT_TOKEN_HELD(&vm_token); 409 KASSERT((m->flags & PG_BUSY) == 0, 410 ("vm_page_busy: page already busy!!!")); 411 vm_page_flag_set(m, PG_BUSY); 412 } 413 414 /* 415 * vm_page_flash: 416 * 417 * wakeup anyone waiting for the page. 418 */ 419 420 static __inline void 421 vm_page_flash(vm_page_t m) 422 { 423 lwkt_gettoken(&vm_token); 424 if (m->flags & PG_WANTED) { 425 vm_page_flag_clear(m, PG_WANTED); 426 wakeup(m); 427 } 428 lwkt_reltoken(&vm_token); 429 } 430 431 /* 432 * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This 433 * is typically the last call you make on a page before moving onto 434 * other things. 435 */ 436 static __inline void 437 vm_page_wakeup(vm_page_t m) 438 { 439 KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!")); 440 vm_page_flag_clear(m, PG_BUSY); 441 vm_page_flash(m); 442 } 443 444 /* 445 * These routines manipulate the 'soft busy' count for a page. A soft busy 446 * is almost like PG_BUSY except that it allows certain compatible operations 447 * to occur on the page while it is busy. For example, a page undergoing a 448 * write can still be mapped read-only. 449 */ 450 static __inline void 451 vm_page_io_start(vm_page_t m) 452 { 453 atomic_add_char(&(m)->busy, 1); 454 } 455 456 static __inline void 457 vm_page_io_finish(vm_page_t m) 458 { 459 atomic_subtract_char(&m->busy, 1); 460 if (m->busy == 0) 461 vm_page_flash(m); 462 } 463 464 465 #if PAGE_SIZE == 4096 466 #define VM_PAGE_BITS_ALL 0xff 467 #endif 468 469 #if PAGE_SIZE == 8192 470 #define VM_PAGE_BITS_ALL 0xffff 471 #endif 472 473 /* 474 * Note: the code will always use nominally free pages from the free list 475 * before trying other flag-specified sources. 476 * 477 * At least one of VM_ALLOC_NORMAL|VM_ALLOC_SYSTEM|VM_ALLOC_INTERRUPT 478 * must be specified. VM_ALLOC_RETRY may only be specified if VM_ALLOC_NORMAL 479 * is also specified. 480 */ 481 #define VM_ALLOC_NORMAL 0x01 /* ok to use cache pages */ 482 #define VM_ALLOC_SYSTEM 0x02 /* ok to exhaust most of free list */ 483 #define VM_ALLOC_INTERRUPT 0x04 /* ok to exhaust entire free list */ 484 #define VM_ALLOC_ZERO 0x08 /* req pre-zero'd memory if avail */ 485 #define VM_ALLOC_QUICK 0x10 /* like NORMAL but do not use cache */ 486 #define VM_ALLOC_RETRY 0x80 /* indefinite block (vm_page_grab()) */ 487 488 void vm_page_hold(vm_page_t); 489 void vm_page_unhold(vm_page_t); 490 void vm_page_activate (vm_page_t); 491 vm_page_t vm_page_alloc (struct vm_object *, vm_pindex_t, int); 492 vm_page_t vm_page_grab (struct vm_object *, vm_pindex_t, int); 493 void vm_page_cache (vm_page_t); 494 int vm_page_try_to_cache (vm_page_t); 495 int vm_page_try_to_free (vm_page_t); 496 void vm_page_dontneed (vm_page_t); 497 void vm_page_deactivate (vm_page_t); 498 void vm_page_insert (vm_page_t, struct vm_object *, vm_pindex_t); 499 vm_page_t vm_page_lookup (struct vm_object *, vm_pindex_t); 500 void vm_page_remove (vm_page_t); 501 void vm_page_rename (vm_page_t, struct vm_object *, vm_pindex_t); 502 vm_offset_t vm_page_startup (vm_offset_t); 503 vm_page_t vm_add_new_page (vm_paddr_t pa); 504 void vm_page_unmanage (vm_page_t); 505 void vm_page_unwire (vm_page_t, int); 506 void vm_page_wire (vm_page_t); 507 void vm_page_unqueue (vm_page_t); 508 void vm_page_unqueue_nowakeup (vm_page_t); 509 void vm_page_set_validclean (vm_page_t, int, int); 510 void vm_page_set_validdirty (vm_page_t, int, int); 511 void vm_page_set_valid (vm_page_t, int, int); 512 void vm_page_set_dirty (vm_page_t, int, int); 513 void vm_page_clear_dirty (vm_page_t, int, int); 514 void vm_page_set_invalid (vm_page_t, int, int); 515 int vm_page_is_valid (vm_page_t, int, int); 516 void vm_page_test_dirty (vm_page_t); 517 int vm_page_bits (int, int); 518 vm_page_t vm_page_list_find(int basequeue, int index, boolean_t prefer_zero); 519 void vm_page_zero_invalid(vm_page_t m, boolean_t setvalid); 520 void vm_page_free_toq(vm_page_t m); 521 vm_page_t vm_page_free_fromq_fast(void); 522 vm_offset_t vm_contig_pg_kmap(int, u_long, vm_map_t, int); 523 void vm_contig_pg_free(int, u_long); 524 void vm_page_event_internal(vm_page_t, vm_page_event_t); 525 void vm_page_dirty(vm_page_t m); 526 527 /* 528 * Reduce the protection of a page. This routine never raises the 529 * protection and therefore can be safely called if the page is already 530 * at VM_PROT_NONE (it will be a NOP effectively ). 531 * 532 * VM_PROT_NONE will remove all user mappings of a page. This is often 533 * necessary when a page changes state (for example, turns into a copy-on-write 534 * page or needs to be frozen for write I/O) in order to force a fault, or 535 * to force a page's dirty bits to be synchronized and avoid hardware 536 * (modified/accessed) bit update races with pmap changes. 537 * 538 * Since 'prot' is usually a constant, this inline usually winds up optimizing 539 * out the primary conditional. 540 * 541 * WARNING: VM_PROT_NONE can block, but will loop until all mappings have 542 * been cleared. Callers should be aware that other page related elements 543 * might have changed, however. 544 */ 545 static __inline void 546 vm_page_protect(vm_page_t mem, int prot) 547 { 548 if (prot == VM_PROT_NONE) { 549 if (mem->flags & (PG_WRITEABLE|PG_MAPPED)) { 550 pmap_page_protect(mem, VM_PROT_NONE); 551 /* PG_WRITEABLE & PG_MAPPED cleared by call */ 552 } 553 } else if ((prot == VM_PROT_READ) && (mem->flags & PG_WRITEABLE)) { 554 pmap_page_protect(mem, VM_PROT_READ); 555 /* PG_WRITEABLE cleared by call */ 556 } 557 } 558 559 /* 560 * Zero-fill the specified page. The entire contents of the page will be 561 * zero'd out. 562 */ 563 static __inline boolean_t 564 vm_page_zero_fill(vm_page_t m) 565 { 566 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 567 return (TRUE); 568 } 569 570 /* 571 * Copy the contents of src_m to dest_m. The pages must be stable but spl 572 * and other protections depend on context. 573 */ 574 static __inline void 575 vm_page_copy(vm_page_t src_m, vm_page_t dest_m) 576 { 577 pmap_copy_page(VM_PAGE_TO_PHYS(src_m), VM_PAGE_TO_PHYS(dest_m)); 578 dest_m->valid = VM_PAGE_BITS_ALL; 579 dest_m->dirty = VM_PAGE_BITS_ALL; 580 } 581 582 /* 583 * Free a page. The page must be marked BUSY. 584 * 585 * The clearing of PG_ZERO is a temporary safety until the code can be 586 * reviewed to determine that PG_ZERO is being properly cleared on 587 * write faults or maps. PG_ZERO was previously cleared in 588 * vm_page_alloc(). 589 */ 590 static __inline void 591 vm_page_free(vm_page_t m) 592 { 593 vm_page_flag_clear(m, PG_ZERO); 594 vm_page_free_toq(m); 595 } 596 597 /* 598 * Free a page to the zerod-pages queue 599 */ 600 static __inline void 601 vm_page_free_zero(vm_page_t m) 602 { 603 #ifdef __x86_64__ 604 /* JG DEBUG64 We check if the page is really zeroed. */ 605 char *p = (char *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m)); 606 int i; 607 608 for (i = 0; i < PAGE_SIZE; i++) { 609 if (p[i] != 0) { 610 panic("non-zero page in vm_page_free_zero()"); 611 } 612 } 613 614 #endif 615 vm_page_flag_set(m, PG_ZERO); 616 vm_page_free_toq(m); 617 } 618 619 /* 620 * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE) 621 * m->busy is zero. Returns TRUE if it had to sleep ( including if 622 * it almost had to sleep and made temporary spl*() mods), FALSE 623 * otherwise. 624 * 625 * This routine assumes that interrupts can only remove the busy 626 * status from a page, not set the busy status or change it from 627 * PG_BUSY to m->busy or vise versa (which would create a timing 628 * window). 629 * 630 * Note: as an inline, 'also_m_busy' is usually a constant and well 631 * optimized. 632 */ 633 static __inline int 634 vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg) 635 { 636 if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) { 637 lwkt_gettoken(&vm_token); 638 if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) { 639 /* 640 * Page is busy. Wait and retry. 641 */ 642 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); 643 tsleep(m, 0, msg, 0); 644 } 645 lwkt_reltoken(&vm_token); 646 return(TRUE); 647 /* not reached */ 648 } 649 return(FALSE); 650 } 651 652 /* 653 * Set page to not be dirty. Note: does not clear pmap modify bits . 654 */ 655 static __inline void 656 vm_page_undirty(vm_page_t m) 657 { 658 m->dirty = 0; 659 } 660 661 #endif /* _KERNEL */ 662 #endif /* !_VM_VM_PAGE_H_ */ 663