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 1.16 2004/10/04 09:05:26 dillon Exp $ 66 */ 67 68 /* 69 * Resident memory system definitions. 70 */ 71 72 #ifndef _VM_PAGE_H_ 73 #define _VM_PAGE_H_ 74 75 #if !defined(KLD_MODULE) && defined(_KERNEL) 76 #include "opt_vmpage.h" 77 #endif 78 79 #include <vm/pmap.h> 80 #include <machine/atomic.h> 81 82 /* 83 * Management of resident (logical) pages. 84 * 85 * A small structure is kept for each resident 86 * page, indexed by page number. Each structure 87 * is an element of several lists: 88 * 89 * A hash table bucket used to quickly 90 * perform object/offset lookups 91 * 92 * A list of all pages for a given object, 93 * so they can be quickly deactivated at 94 * time of deallocation. 95 * 96 * An ordered list of pages due for pageout. 97 * 98 * In addition, the structure contains the object 99 * and offset to which this page belongs (for pageout), 100 * and sundry status bits. 101 * 102 * Fields in this structure are locked either by the lock on the 103 * object that the page belongs to (O) or by the lock on the page 104 * queues (P). 105 * 106 * The 'valid' and 'dirty' fields are distinct. A page may have dirty 107 * bits set without having associated valid bits set. This is used by 108 * NFS to implement piecemeal writes. 109 */ 110 111 TAILQ_HEAD(pglist, vm_page); 112 113 struct vm_page { 114 TAILQ_ENTRY(vm_page) pageq; /* vm_page_queues[] list (P) */ 115 struct vm_page *hnext; /* hash table link (O,P) */ 116 TAILQ_ENTRY(vm_page) listq; /* pages in same object (O) */ 117 118 vm_object_t object; /* which object am I in (O,P)*/ 119 vm_pindex_t pindex; /* offset into object (O,P) */ 120 vm_paddr_t phys_addr; /* physical address of page */ 121 struct md_page md; /* machine dependant stuff */ 122 u_short queue; /* page queue index */ 123 u_short flags; /* see below */ 124 u_short pc; /* page color */ 125 u_short wire_count; /* wired down maps refs (P) */ 126 short hold_count; /* page hold count */ 127 u_char act_count; /* page usage count */ 128 u_char busy; /* page busy count */ 129 130 /* 131 * NOTE that these must support one bit per DEV_BSIZE in a page!!! 132 * so, on normal X86 kernels, they must be at least 8 bits wide. 133 */ 134 #if PAGE_SIZE == 4096 135 u_char valid; /* map of valid DEV_BSIZE chunks */ 136 u_char dirty; /* map of dirty DEV_BSIZE chunks */ 137 #elif PAGE_SIZE == 8192 138 u_short valid; /* map of valid DEV_BSIZE chunks */ 139 u_short dirty; /* map of dirty DEV_BSIZE chunks */ 140 #endif 141 }; 142 143 /* 144 * note: currently use SWAPBLK_NONE as an absolute value rather then 145 * a flag bit. 146 */ 147 #define SWAPBLK_MASK ((daddr_t)((u_daddr_t)-1 >> 1)) /* mask */ 148 #define SWAPBLK_NONE ((daddr_t)((u_daddr_t)SWAPBLK_MASK + 1))/* flag */ 149 150 /* 151 * Page coloring parameters. We default to a middle of the road optimization. 152 * Larger selections would not really hurt us but if a machine does not have 153 * a lot of memory it could cause vm_page_alloc() to eat more cpu cycles 154 * looking for free pages. 155 * 156 * Page coloring cannot be disabled. Modules do not have access to most PQ 157 * constants because they can change between builds. 158 */ 159 #if defined(_KERNEL) && !defined(KLD_MODULE) 160 161 #if !defined(PQ_CACHESIZE) 162 #define PQ_CACHESIZE 256 /* max is 1024 (MB) */ 163 #endif 164 165 #if PQ_CACHESIZE >= 1024 166 #define PQ_PRIME1 31 /* Prime number somewhat less than PQ_HASH_SIZE */ 167 #define PQ_PRIME2 23 /* Prime number somewhat less than PQ_HASH_SIZE */ 168 #define PQ_L2_SIZE 256 /* A number of colors opt for 1M cache */ 169 170 #elif PQ_CACHESIZE >= 512 171 #define PQ_PRIME1 31 /* Prime number somewhat less than PQ_HASH_SIZE */ 172 #define PQ_PRIME2 23 /* Prime number somewhat less than PQ_HASH_SIZE */ 173 #define PQ_L2_SIZE 128 /* A number of colors opt for 512K cache */ 174 175 #elif PQ_CACHESIZE >= 256 176 #define PQ_PRIME1 13 /* Prime number somewhat less than PQ_HASH_SIZE */ 177 #define PQ_PRIME2 7 /* Prime number somewhat less than PQ_HASH_SIZE */ 178 #define PQ_L2_SIZE 64 /* A number of colors opt for 256K cache */ 179 180 #elif PQ_CACHESIZE >= 128 181 #define PQ_PRIME1 9 /* Produces a good PQ_L2_SIZE/3 + PQ_PRIME1 */ 182 #define PQ_PRIME2 5 /* Prime number somewhat less than PQ_HASH_SIZE */ 183 #define PQ_L2_SIZE 32 /* A number of colors opt for 128k cache */ 184 185 #else 186 #define PQ_PRIME1 5 /* Prime number somewhat less than PQ_HASH_SIZE */ 187 #define PQ_PRIME2 3 /* Prime number somewhat less than PQ_HASH_SIZE */ 188 #define PQ_L2_SIZE 16 /* A reasonable number of colors (opt for 64K cache) */ 189 190 #endif 191 192 #define PQ_L2_MASK (PQ_L2_SIZE - 1) 193 194 #endif /* KERNEL && !KLD_MODULE */ 195 196 /* 197 * 198 * The queue array is always based on PQ_MAXL2_SIZE regardless of the actual 199 * cache size chosen in order to present a uniform interface for modules. 200 */ 201 #define PQ_MAXL2_SIZE 256 /* fixed maximum (in pages) / module compat */ 202 203 #if PQ_L2_SIZE > PQ_MAXL2_SIZE 204 #error "Illegal PQ_L2_SIZE" 205 #endif 206 207 #define PQ_NONE 0 208 #define PQ_FREE 1 209 #define PQ_INACTIVE (1 + 1*PQ_MAXL2_SIZE) 210 #define PQ_ACTIVE (2 + 1*PQ_MAXL2_SIZE) 211 #define PQ_CACHE (3 + 1*PQ_MAXL2_SIZE) 212 #define PQ_HOLD (3 + 2*PQ_MAXL2_SIZE) 213 #define PQ_COUNT (4 + 2*PQ_MAXL2_SIZE) 214 215 struct vpgqueues { 216 struct pglist pl; 217 int *cnt; 218 int lcnt; 219 int flipflop; /* probably not the best place */ 220 }; 221 222 extern struct vpgqueues vm_page_queues[PQ_COUNT]; 223 224 /* 225 * These are the flags defined for vm_page. 226 * 227 * Note: PG_UNMANAGED (used by OBJT_PHYS) indicates that the page is 228 * not under PV management but otherwise should be treated as a 229 * normal page. Pages not under PV management cannot be paged out 230 * via the object/vm_page_t because there is no knowledge of their 231 * pte mappings, nor can they be removed from their objects via 232 * the object, and such pages are also not on any PQ queue. 233 */ 234 #define PG_BUSY 0x0001 /* page is in transit (O) */ 235 #define PG_WANTED 0x0002 /* someone is waiting for page (O) */ 236 #define PG_WINATCFLS 0x0004 /* flush dirty page on inactive q */ 237 #define PG_FICTITIOUS 0x0008 /* physical page doesn't exist (O) */ 238 #define PG_WRITEABLE 0x0010 /* page is mapped writeable */ 239 #define PG_MAPPED 0x0020 /* page is mapped */ 240 #define PG_ZERO 0x0040 /* page is zeroed */ 241 #define PG_REFERENCED 0x0080 /* page has been referenced */ 242 #define PG_CLEANCHK 0x0100 /* page will be checked for cleaning */ 243 #define PG_SWAPINPROG 0x0200 /* swap I/O in progress on page */ 244 #define PG_NOSYNC 0x0400 /* do not collect for syncer */ 245 #define PG_UNMANAGED 0x0800 /* No PV management for page */ 246 #define PG_MARKER 0x1000 /* special queue marker page */ 247 248 /* 249 * Misc constants. 250 */ 251 252 #define ACT_DECLINE 1 253 #define ACT_ADVANCE 3 254 #define ACT_INIT 5 255 #define ACT_MAX 64 256 257 #ifdef _KERNEL 258 /* 259 * Each pageable resident page falls into one of four lists: 260 * 261 * free 262 * Available for allocation now. 263 * 264 * The following are all LRU sorted: 265 * 266 * cache 267 * Almost available for allocation. Still in an 268 * object, but clean and immediately freeable at 269 * non-interrupt times. 270 * 271 * inactive 272 * Low activity, candidates for reclamation. 273 * This is the list of pages that should be 274 * paged out next. 275 * 276 * active 277 * Pages that are "active" i.e. they have been 278 * recently referenced. 279 * 280 * zero 281 * Pages that are really free and have been pre-zeroed 282 * 283 */ 284 285 extern int vm_page_zero_count; 286 extern vm_page_t vm_page_array; /* First resident page in table */ 287 extern int vm_page_array_size; /* number of vm_page_t's */ 288 extern long first_page; /* first physical page number */ 289 290 #define VM_PAGE_TO_PHYS(entry) \ 291 ((entry)->phys_addr) 292 293 #define PHYS_TO_VM_PAGE(pa) \ 294 (&vm_page_array[atop(pa) - first_page]) 295 296 /* 297 * Functions implemented as macros 298 */ 299 300 static __inline void 301 vm_page_flag_set(vm_page_t m, unsigned int bits) 302 { 303 atomic_set_short(&(m)->flags, bits); 304 } 305 306 static __inline void 307 vm_page_flag_clear(vm_page_t m, unsigned int bits) 308 { 309 atomic_clear_short(&(m)->flags, bits); 310 } 311 312 static __inline void 313 vm_page_busy(vm_page_t m) 314 { 315 KASSERT((m->flags & PG_BUSY) == 0, 316 ("vm_page_busy: page already busy!!!")); 317 vm_page_flag_set(m, PG_BUSY); 318 } 319 320 /* 321 * vm_page_flash: 322 * 323 * wakeup anyone waiting for the page. 324 */ 325 326 static __inline void 327 vm_page_flash(vm_page_t m) 328 { 329 if (m->flags & PG_WANTED) { 330 vm_page_flag_clear(m, PG_WANTED); 331 wakeup(m); 332 } 333 } 334 335 /* 336 * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This 337 * is typically the last call you make on a page before moving onto 338 * other things. 339 */ 340 static __inline void 341 vm_page_wakeup(vm_page_t m) 342 { 343 KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!")); 344 vm_page_flag_clear(m, PG_BUSY); 345 vm_page_flash(m); 346 } 347 348 /* 349 * These routines manipulate the 'soft busy' count for a page. A soft busy 350 * is almost like PG_BUSY except that it allows certain compatible operations 351 * to occur on the page while it is busy. For example, a page undergoing a 352 * write can still be mapped read-only. 353 */ 354 static __inline void 355 vm_page_io_start(vm_page_t m) 356 { 357 atomic_add_char(&(m)->busy, 1); 358 } 359 360 static __inline void 361 vm_page_io_finish(vm_page_t m) 362 { 363 atomic_subtract_char(&m->busy, 1); 364 if (m->busy == 0) 365 vm_page_flash(m); 366 } 367 368 369 #if PAGE_SIZE == 4096 370 #define VM_PAGE_BITS_ALL 0xff 371 #endif 372 373 #if PAGE_SIZE == 8192 374 #define VM_PAGE_BITS_ALL 0xffff 375 #endif 376 377 /* 378 * Note: the code will always use nominally free pages from the free list 379 * before trying other flag-specified sources. 380 * 381 * At least one of VM_ALLOC_NORMAL|VM_ALLOC_SYSTEM|VM_ALLOC_INTERRUPT 382 * must be specified. VM_ALLOC_RETRY may only be specified if VM_ALLOC_NORMAL 383 * is also specified. 384 */ 385 #define VM_ALLOC_NORMAL 0x01 /* ok to use cache pages */ 386 #define VM_ALLOC_SYSTEM 0x02 /* ok to exhaust most of free list */ 387 #define VM_ALLOC_INTERRUPT 0x04 /* ok to exhaust entire free list */ 388 #define VM_ALLOC_ZERO 0x08 /* req pre-zero'd memory if avail */ 389 #define VM_ALLOC_RETRY 0x80 /* indefinite block (vm_page_grab()) */ 390 391 void vm_page_unhold(vm_page_t mem); 392 void vm_page_activate (vm_page_t); 393 vm_page_t vm_page_alloc (vm_object_t, vm_pindex_t, int); 394 vm_page_t vm_page_grab (vm_object_t, vm_pindex_t, int); 395 void vm_page_cache (vm_page_t); 396 int vm_page_try_to_cache (vm_page_t); 397 int vm_page_try_to_free (vm_page_t); 398 void vm_page_dontneed (vm_page_t); 399 void vm_page_deactivate (vm_page_t); 400 void vm_page_insert (vm_page_t, vm_object_t, vm_pindex_t); 401 vm_page_t vm_page_lookup (vm_object_t, vm_pindex_t); 402 void vm_page_remove (vm_page_t); 403 void vm_page_rename (vm_page_t, vm_object_t, vm_pindex_t); 404 vm_offset_t vm_page_startup (vm_offset_t, vm_offset_t, vm_offset_t); 405 vm_page_t vm_add_new_page (vm_paddr_t pa); 406 void vm_page_unmanage (vm_page_t); 407 void vm_page_unwire (vm_page_t, int); 408 void vm_page_wire (vm_page_t); 409 void vm_page_unqueue (vm_page_t); 410 void vm_page_unqueue_nowakeup (vm_page_t); 411 void vm_page_set_validclean (vm_page_t, int, int); 412 void vm_page_set_dirty (vm_page_t, int, int); 413 void vm_page_clear_dirty (vm_page_t, int, int); 414 void vm_page_set_invalid (vm_page_t, int, int); 415 int vm_page_is_valid (vm_page_t, int, int); 416 void vm_page_test_dirty (vm_page_t); 417 int vm_page_bits (int, int); 418 vm_page_t vm_page_list_find(int basequeue, int index, boolean_t prefer_zero); 419 void vm_page_zero_invalid(vm_page_t m, boolean_t setvalid); 420 void vm_page_free_toq(vm_page_t m); 421 int vm_contig_pg_alloc(u_long, vm_paddr_t, vm_paddr_t, u_long, u_long); 422 vm_offset_t vm_contig_pg_kmap(int, u_long, vm_map_t, int); 423 void vm_contig_pg_free(int, u_long); 424 425 /* 426 * Holding a page keeps it from being reused. Other parts of the system 427 * can still disassociate the page from its current object and free it, or 428 * perform read or write I/O on it and/or otherwise manipulate the page, 429 * but if the page is held the VM system will leave the page and its data 430 * intact and not reuse the page for other purposes until the last hold 431 * reference is released. (see vm_page_wire() if you want to prevent the 432 * page from being disassociated from its object too). 433 * 434 * This routine must be called while at splvm() or better. 435 * 436 * The caller must still validate the contents of the page and, if necessary, 437 * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete 438 * before manipulating the page. 439 */ 440 static __inline void 441 vm_page_hold(vm_page_t mem) 442 { 443 mem->hold_count++; 444 } 445 446 /* 447 * Reduce the protection of a page. This routine never raises the 448 * protection and therefore can be safely called if the page is already 449 * at VM_PROT_NONE (it will be a NOP effectively ). 450 * 451 * VM_PROT_NONE will remove all user mappings of a page. This is often 452 * necessary when a page changes state (for example, turns into a copy-on-write 453 * page or needs to be frozen for write I/O) in order to force a fault, or 454 * to force a page's dirty bits to be synchronized and avoid hardware 455 * (modified/accessed) bit update races with pmap changes. 456 * 457 * Since 'prot' is usually a constant, this inline usually winds up optimizing 458 * out the primary conditional. 459 */ 460 static __inline void 461 vm_page_protect(vm_page_t mem, int prot) 462 { 463 if (prot == VM_PROT_NONE) { 464 if (mem->flags & (PG_WRITEABLE|PG_MAPPED)) { 465 pmap_page_protect(mem, VM_PROT_NONE); 466 vm_page_flag_clear(mem, PG_WRITEABLE|PG_MAPPED); 467 } 468 } else if ((prot == VM_PROT_READ) && (mem->flags & PG_WRITEABLE)) { 469 pmap_page_protect(mem, VM_PROT_READ); 470 vm_page_flag_clear(mem, PG_WRITEABLE); 471 } 472 } 473 474 /* 475 * Zero-fill the specified page. The entire contents of the page will be 476 * zero'd out. 477 */ 478 static __inline boolean_t 479 vm_page_zero_fill(vm_page_t m) 480 { 481 pmap_zero_page(VM_PAGE_TO_PHYS(m)); 482 return (TRUE); 483 } 484 485 /* 486 * Copy the contents of src_m to dest_m. The pages must be stable but spl 487 * and other protections depend on context. 488 */ 489 static __inline void 490 vm_page_copy(vm_page_t src_m, vm_page_t dest_m) 491 { 492 pmap_copy_page(VM_PAGE_TO_PHYS(src_m), VM_PAGE_TO_PHYS(dest_m)); 493 dest_m->valid = VM_PAGE_BITS_ALL; 494 } 495 496 /* 497 * Free a page. The page must be marked BUSY. 498 * 499 * The clearing of PG_ZERO is a temporary safety until the code can be 500 * reviewed to determine that PG_ZERO is being properly cleared on 501 * write faults or maps. PG_ZERO was previously cleared in 502 * vm_page_alloc(). 503 */ 504 static __inline void 505 vm_page_free(vm_page_t m) 506 { 507 vm_page_flag_clear(m, PG_ZERO); 508 vm_page_free_toq(m); 509 } 510 511 /* 512 * Free a page to the zerod-pages queue 513 */ 514 static __inline void 515 vm_page_free_zero(vm_page_t m) 516 { 517 vm_page_flag_set(m, PG_ZERO); 518 vm_page_free_toq(m); 519 } 520 521 /* 522 * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE) 523 * m->busy is zero. Returns TRUE if it had to sleep ( including if 524 * it almost had to sleep and made temporary spl*() mods), FALSE 525 * otherwise. 526 * 527 * This routine assumes that interrupts can only remove the busy 528 * status from a page, not set the busy status or change it from 529 * PG_BUSY to m->busy or vise versa (which would create a timing 530 * window). 531 * 532 * Note: as an inline, 'also_m_busy' is usually a constant and well 533 * optimized. 534 */ 535 static __inline int 536 vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg) 537 { 538 if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) { 539 int s = splvm(); 540 if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) { 541 /* 542 * Page is busy. Wait and retry. 543 */ 544 vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); 545 tsleep(m, 0, msg, 0); 546 } 547 splx(s); 548 return(TRUE); 549 /* not reached */ 550 } 551 return(FALSE); 552 } 553 554 /* 555 * Make page all dirty 556 */ 557 static __inline void 558 vm_page_dirty(vm_page_t m) 559 { 560 KASSERT(m->queue - m->pc != PQ_CACHE, 561 ("vm_page_dirty: page in cache!")); 562 m->dirty = VM_PAGE_BITS_ALL; 563 } 564 565 /* 566 * Set page to not be dirty. Note: does not clear pmap modify bits . 567 */ 568 static __inline void 569 vm_page_undirty(vm_page_t m) 570 { 571 m->dirty = 0; 572 } 573 574 #endif /* _KERNEL */ 575 #endif /* !_VM_PAGE_ */ 576