1 /* $NetBSD: uvm_page.h,v 1.109 2020/12/20 16:38:26 skrll 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. 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 * @(#)vm_page.h 7.3 (Berkeley) 4/21/91 37 * from: Id: uvm_page.h,v 1.1.2.6 1998/02/04 02:31:42 chuck Exp 38 * 39 * 40 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 41 * All rights reserved. 42 * 43 * Permission to use, copy, modify and distribute this software and 44 * its documentation is hereby granted, provided that both the copyright 45 * notice and this permission notice appear in all copies of the 46 * software, derivative works or modified versions, and any portions 47 * thereof, and that both notices appear in supporting documentation. 48 * 49 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 50 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 51 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 52 * 53 * Carnegie Mellon requests users of this software to return to 54 * 55 * Software Distribution Coordinator or Software.Distribution (at) CS.CMU.EDU 56 * School of Computer Science 57 * Carnegie Mellon University 58 * Pittsburgh PA 15213-3890 59 * 60 * any improvements or extensions that they make and grant Carnegie the 61 * rights to redistribute these changes. 62 */ 63 64 #ifndef _UVM_UVM_PAGE_H_ 65 #define _UVM_UVM_PAGE_H_ 66 67 #ifdef _KERNEL_OPT 68 #include "opt_uvm_page_trkown.h" 69 #endif 70 71 #include <sys/rwlock.h> 72 73 #include <uvm/uvm_extern.h> 74 #include <uvm/uvm_pglist.h> 75 76 /* 77 * Management of resident (logical) pages. 78 * 79 * Each resident page has a vm_page structure, indexed by page number. 80 * There are several lists in the structure: 81 * 82 * - A red-black tree rooted with the containing object is used to 83 * quickly perform object+offset lookups. 84 * - A list of all pages for a given object, for a quick deactivation 85 * at a time of deallocation. 86 * - An ordered list of pages due for pageout. 87 * 88 * In addition, the structure contains the object and offset to which 89 * this page belongs (for pageout) and sundry status bits. 90 * 91 * Note that the page structure has no lock of its own. The page is 92 * generally protected by its owner's lock (UVM object or amap/anon). 93 * It should be noted that UVM has to serialize pmap(9) operations on 94 * the managed pages, e.g. for pmap_enter() calls. Hence, the lock 95 * order is as follows: 96 * 97 * [vmpage-owner-lock] -> 98 * any pmap locks (e.g. PV hash lock) 99 * 100 * Since the kernel is always self-consistent, no serialization is 101 * required for unmanaged mappings, e.g. for pmap_kenter_pa() calls. 102 * 103 * Field markings and the corresponding locks: 104 * 105 * f: free page queue lock, uvm_fpageqlock 106 * o: page owner (uvm_object::vmobjlock, vm_amap::am_lock, vm_anon::an_lock) 107 * i: vm_page::interlock 108 * => flags set and cleared only with o&i held can 109 * safely be tested for with only o held. 110 * o,i: o|i for read, o&i for write (depends on context - if could be loaned) 111 * => see uvm_loan.c 112 * w: wired page queue or uvm_pglistalloc: 113 * => wired page queue: o&i to change, stable from wire to unwire 114 * XXX What about concurrent or nested wire? 115 * => uvm_pglistalloc: owned by caller 116 * ?: locked by pmap or assumed page owner's lock 117 * p: locked by pagedaemon policy module (pdpolicy) 118 * c: cpu private 119 * s: stable, does not change 120 * 121 * UVM and pmap(9) may use uvm_page_owner_locked_p() to assert whether the 122 * page owner's lock is acquired. 123 * 124 * A page can have one of four identities: 125 * 126 * o free 127 * => pageq.list is entry on global free page queue 128 * => uanon is unused (or (void *)0xdeadbeef for DEBUG) 129 * => uobject is unused (or (void *)0xdeadbeef for DEBUG) 130 * => PG_FREE is set in flags 131 * o owned by a uvm_object 132 * => pageq.queue is entry on wired page queue, if any 133 * => uanon is NULL or the vm_anon to which it has been O->A loaned 134 * => uobject is owner 135 * o owned by a vm_anon 136 * => pageq is unused (XXX correct?) 137 * => uanon is owner 138 * => uobject is NULL 139 * => PG_ANON is set in flags 140 * o allocated by uvm_pglistalloc 141 * => pageq.queue is entry on resulting pglist, owned by caller 142 * => uanon is unused 143 * => uobject is unused 144 * 145 * The following transitions are allowed: 146 * 147 * - uvm_pagealloc: free -> owned by a uvm_object/vm_anon 148 * - uvm_pagefree: owned by a uvm_object/vm_anon -> free 149 * - uvm_pglistalloc: free -> allocated by uvm_pglistalloc 150 * - uvm_pglistfree: allocated by uvm_pglistalloc -> free 151 * 152 * On the ordering of fields: 153 * 154 * The fields most heavily used during fault processing are clustered 155 * together at the start of the structure to reduce cache misses. 156 * XXX This entire thing should be shrunk to fit in one cache line. 157 */ 158 159 struct vm_page { 160 /* _LP64: first cache line */ 161 union { 162 TAILQ_ENTRY(vm_page) queue; /* w: wired page queue 163 * or uvm_pglistalloc output */ 164 LIST_ENTRY(vm_page) list; /* f: global free page queue */ 165 } pageq; 166 uint32_t pqflags; /* i: pagedaemon flags */ 167 uint32_t flags; /* o: object flags */ 168 paddr_t phys_addr; /* o: physical address of pg */ 169 uint32_t loan_count; /* o,i: num. active loans */ 170 uint32_t wire_count; /* o,i: wired down map refs */ 171 struct vm_anon *uanon; /* o,i: anon */ 172 struct uvm_object *uobject; /* o,i: object */ 173 voff_t offset; /* o: offset into object */ 174 175 /* _LP64: second cache line */ 176 kmutex_t interlock; /* s: lock on identity */ 177 TAILQ_ENTRY(vm_page) pdqueue; /* p: pagedaemon queue */ 178 179 #ifdef __HAVE_VM_PAGE_MD 180 struct vm_page_md mdpage; /* ?: pmap-specific data */ 181 #endif 182 183 #if defined(UVM_PAGE_TRKOWN) 184 /* debugging fields to track page ownership */ 185 pid_t owner; /* proc that set PG_BUSY */ 186 lwpid_t lowner; /* lwp that set PG_BUSY */ 187 const char *owner_tag; /* why it was set busy */ 188 #endif 189 }; 190 191 /* 192 * Overview of UVM page flags, stored in pg->flags. 193 * 194 * Locking notes: 195 * 196 * PG_, struct vm_page::flags => locked by owner 197 * PG_AOBJ => additionally locked by vm_page::interlock 198 * PG_ANON => additionally locked by vm_page::interlock 199 * PG_FREE => additionally locked by uvm_fpageqlock 200 * for uvm_pglistalloc() 201 * 202 * Flag descriptions: 203 * 204 * PG_CLEAN: 205 * Page is known clean. 206 * The contents of the page is consistent with its backing store. 207 * 208 * PG_DIRTY: 209 * Page is known dirty. 210 * To avoid losing data, the contents of the page should be written 211 * back to the backing store before freeing the page. 212 * 213 * PG_BUSY: 214 * Page is long-term locked, usually because of I/O (transfer from the 215 * page memory to the backing store) is in progress. LWP attempting 216 * to access the page shall set PQ_WANTED and wait. PG_BUSY may only 217 * be set with a write lock held on the object. 218 * 219 * PG_PAGEOUT: 220 * Indicates that the page is being paged-out in preparation for 221 * being freed. 222 * 223 * PG_RELEASED: 224 * Indicates that the page, which is currently PG_BUSY, should be freed 225 * after the release of long-term lock. It is responsibility of the 226 * owning LWP (i.e. which set PG_BUSY) to do it. 227 * 228 * PG_FAKE: 229 * Page has been allocated, but not yet initialised. The flag is used 230 * to avoid overwriting of valid data, e.g. to prevent read from the 231 * backing store when in-core data is newer. 232 * 233 * PG_RDONLY: 234 * Indicates that the page must be mapped read-only. 235 * 236 * PG_MARKER: 237 * Dummy marker page, generally used for list traversal. 238 */ 239 240 /* 241 * if you want to renumber PG_CLEAN and PG_DIRTY, check __CTASSERTs in 242 * uvm_page_status.c first. 243 */ 244 245 #define PG_CLEAN 0x00000001 /* page is known clean */ 246 #define PG_DIRTY 0x00000002 /* page is known dirty */ 247 #define PG_BUSY 0x00000004 /* page is locked */ 248 #define PG_PAGEOUT 0x00000010 /* page to be freed for pagedaemon */ 249 #define PG_RELEASED 0x00000020 /* page to be freed when unbusied */ 250 #define PG_FAKE 0x00000040 /* page is not yet initialized */ 251 #define PG_RDONLY 0x00000080 /* page must be mapped read-only */ 252 #define PG_TABLED 0x00000200 /* page is tabled in object */ 253 #define PG_AOBJ 0x00000400 /* page is part of an anonymous 254 uvm_object */ 255 #define PG_ANON 0x00000800 /* page is part of an anon, rather 256 than an uvm_object */ 257 #define PG_FILE 0x00001000 /* file backed (non-anonymous) */ 258 #define PG_READAHEAD 0x00002000 /* read-ahead but not "hit" yet */ 259 #define PG_FREE 0x00004000 /* page is on free list */ 260 #define PG_MARKER 0x00008000 /* dummy marker page */ 261 #define PG_PAGER1 0x00010000 /* pager-specific flag */ 262 #define PG_PGLCA 0x00020000 /* allocated by uvm_pglistalloc_contig */ 263 264 #define PG_STAT (PG_ANON|PG_AOBJ|PG_FILE) 265 #define PG_SWAPBACKED (PG_ANON|PG_AOBJ) 266 267 #define UVM_PGFLAGBITS \ 268 "\20\1CLEAN\2DIRTY\3BUSY" \ 269 "\5PAGEOUT\6RELEASED\7FAKE\10RDONLY" \ 270 "\11ZERO\12TABLED\13AOBJ\14ANON" \ 271 "\15FILE\16READAHEAD\17FREE\20MARKER" \ 272 "\21PAGER1\22PGLCA" 273 274 /* 275 * Flags stored in pg->pqflags, which is protected by pg->interlock. 276 * 277 * PQ_PRIVATE: 278 * ... is for uvmpdpol to do whatever it wants with. 279 * 280 * PQ_INTENT_SET: 281 * Indicates that the intent set on the page has not yet been realized. 282 * 283 * PQ_INTENT_QUEUED: 284 * Indicates that the page is, or will soon be, on a per-CPU queue for 285 * the intent to be realized. 286 * 287 * PQ_WANTED: 288 * Indicates that the page, which is currently PG_BUSY, is wanted by 289 * some other LWP. The page owner (i.e. LWP which set PG_BUSY) is 290 * responsible to clear both flags and wake up any waiters once it has 291 * released the long-term lock (PG_BUSY). 292 */ 293 294 #define PQ_INTENT_A 0x00000000 /* intend activation */ 295 #define PQ_INTENT_I 0x00000001 /* intend deactivation */ 296 #define PQ_INTENT_E 0x00000002 /* intend enqueue */ 297 #define PQ_INTENT_D 0x00000003 /* intend dequeue */ 298 #define PQ_INTENT_MASK 0x00000003 /* mask of intended state */ 299 #define PQ_INTENT_SET 0x00000004 /* not realized yet */ 300 #define PQ_INTENT_QUEUED 0x00000008 /* queued for processing */ 301 #define PQ_PRIVATE 0x00000ff0 /* private for pdpolicy */ 302 #define PQ_WANTED 0x00001000 /* someone is waiting for page */ 303 304 #define UVM_PQFLAGBITS \ 305 "\20\1INTENT_0\2INTENT_1\3INTENT_SET\4INTENT_QUEUED" \ 306 "\5PRIVATE1\6PRIVATE2\7PRIVATE3\10PRIVATE4" \ 307 "\11PRIVATE5\12PRIVATE6\13PRIVATE7\14PRIVATE8" \ 308 "\15WANTED" 309 310 /* 311 * physical memory layout structure 312 * 313 * MD vmparam.h must #define: 314 * VM_PHYSEG_MAX = max number of physical memory segments we support 315 * (if this is "1" then we revert to a "contig" case) 316 * VM_PHYSSEG_STRAT: memory sort/search options (for VM_PHYSEG_MAX > 1) 317 * - VM_PSTRAT_RANDOM: linear search (random order) 318 * - VM_PSTRAT_BSEARCH: binary search (sorted by address) 319 * - VM_PSTRAT_BIGFIRST: linear search (sorted by largest segment first) 320 * - others? 321 * XXXCDC: eventually we should purge all left-over global variables... 322 */ 323 #define VM_PSTRAT_RANDOM 1 324 #define VM_PSTRAT_BSEARCH 2 325 #define VM_PSTRAT_BIGFIRST 3 326 327 #ifdef _KERNEL 328 329 /* 330 * prototypes: the following prototypes define the interface to pages 331 */ 332 333 void uvm_page_init(vaddr_t *, vaddr_t *); 334 void uvm_pglistalloc_init(void); 335 #if defined(UVM_PAGE_TRKOWN) 336 void uvm_page_own(struct vm_page *, const char *); 337 #endif 338 #if !defined(PMAP_STEAL_MEMORY) 339 bool uvm_page_physget(paddr_t *); 340 #endif 341 void uvm_page_recolor(int); 342 void uvm_page_rebucket(void); 343 344 void uvm_pageactivate(struct vm_page *); 345 vaddr_t uvm_pageboot_alloc(vsize_t); 346 void uvm_pagecopy(struct vm_page *, struct vm_page *); 347 void uvm_pagedeactivate(struct vm_page *); 348 void uvm_pagedequeue(struct vm_page *); 349 void uvm_pageenqueue(struct vm_page *); 350 void uvm_pagefree(struct vm_page *); 351 void uvm_pagelock(struct vm_page *); 352 void uvm_pagelock2(struct vm_page *, struct vm_page *); 353 void uvm_pageunlock(struct vm_page *); 354 void uvm_pageunlock2(struct vm_page *, struct vm_page *); 355 void uvm_page_unbusy(struct vm_page **, int); 356 struct vm_page *uvm_pagelookup(struct uvm_object *, voff_t); 357 void uvm_pageunwire(struct vm_page *); 358 void uvm_pagewire(struct vm_page *); 359 void uvm_pagezero(struct vm_page *); 360 bool uvm_pageismanaged(paddr_t); 361 bool uvm_page_owner_locked_p(struct vm_page *, bool); 362 void uvm_pgfl_lock(void); 363 void uvm_pgfl_unlock(void); 364 unsigned int uvm_pagegetdirty(struct vm_page *); 365 void uvm_pagemarkdirty(struct vm_page *, unsigned int); 366 bool uvm_pagecheckdirty(struct vm_page *, bool); 367 bool uvm_pagereadonly_p(struct vm_page *); 368 bool uvm_page_locked_p(struct vm_page *); 369 void uvm_pagewakeup(struct vm_page *); 370 bool uvm_pagewanted_p(struct vm_page *); 371 void uvm_pagewait(struct vm_page *, krwlock_t *, const char *); 372 373 int uvm_page_lookup_freelist(struct vm_page *); 374 375 struct vm_page *uvm_phys_to_vm_page(paddr_t); 376 paddr_t uvm_vm_page_to_phys(const struct vm_page *); 377 378 #if defined(PMAP_DIRECT) 379 extern bool ubc_direct; 380 int uvm_direct_process(struct vm_page **, u_int, voff_t, vsize_t, 381 int (*)(void *, size_t, void *), void *); 382 #endif 383 384 /* 385 * page dirtiness status for uvm_pagegetdirty and uvm_pagemarkdirty 386 * 387 * UNKNOWN means that we need to consult pmap to know if the page is 388 * dirty or not. 389 * basically, UVM_PAGE_STATUS_CLEAN implies that the page has no writable 390 * mapping. 391 * 392 * if you want to renumber these, check __CTASSERTs in 393 * uvm_page_status.c first. 394 */ 395 396 #define UVM_PAGE_STATUS_UNKNOWN 0 397 #define UVM_PAGE_STATUS_CLEAN 1 398 #define UVM_PAGE_STATUS_DIRTY 2 399 #define UVM_PAGE_NUM_STATUS 3 400 401 /* 402 * macros 403 */ 404 405 #define VM_PAGE_TO_PHYS(entry) uvm_vm_page_to_phys(entry) 406 407 #ifdef __HAVE_VM_PAGE_MD 408 #define VM_PAGE_TO_MD(pg) (&(pg)->mdpage) 409 #define VM_MD_TO_PAGE(md) (container_of((md), struct vm_page, mdpage)) 410 #endif 411 412 /* 413 * Compute the page color for a given page. 414 */ 415 #define VM_PGCOLOR(pg) \ 416 (atop(VM_PAGE_TO_PHYS((pg))) & uvmexp.colormask) 417 #define PHYS_TO_VM_PAGE(pa) uvm_phys_to_vm_page(pa) 418 419 /* 420 * VM_PAGE_IS_FREE() can't tell if the page is on global free list, or a 421 * per-CPU cache. If you need to be certain, pause caching. 422 */ 423 #define VM_PAGE_IS_FREE(entry) ((entry)->flags & PG_FREE) 424 425 /* 426 * Use the lower 10 bits of pg->phys_addr to cache some some locators for 427 * the page. This implies that the smallest possible page size is 1kB, and 428 * that nobody should use pg->phys_addr directly (use VM_PAGE_TO_PHYS()). 429 * 430 * - 5 bits for the freelist index, because uvm_page_lookup_freelist() 431 * traverses an rbtree and therefore features prominently in traces 432 * captured during performance test. It would probably be more useful to 433 * cache physseg index here because freelist can be inferred from physseg, 434 * but it requires changes to allocation for UVM_HOTPLUG, so for now we'll 435 * go with freelist. 436 * 437 * - 5 bits for "bucket", a way for us to categorise pages further as 438 * needed (e.g. NUMA node). 439 * 440 * None of this is set in stone; it can be adjusted as needed. 441 */ 442 443 #define UVM_PHYSADDR_FREELIST __BITS(0,4) 444 #define UVM_PHYSADDR_BUCKET __BITS(5,9) 445 446 static inline unsigned 447 uvm_page_get_freelist(struct vm_page *pg) 448 { 449 unsigned fl = __SHIFTOUT(pg->phys_addr, UVM_PHYSADDR_FREELIST); 450 KASSERT(fl == (unsigned)uvm_page_lookup_freelist(pg)); 451 return fl; 452 } 453 454 static inline unsigned 455 uvm_page_get_bucket(struct vm_page *pg) 456 { 457 return __SHIFTOUT(pg->phys_addr, UVM_PHYSADDR_BUCKET); 458 } 459 460 static inline void 461 uvm_page_set_freelist(struct vm_page *pg, unsigned fl) 462 { 463 KASSERT(fl < 32); 464 pg->phys_addr &= ~UVM_PHYSADDR_FREELIST; 465 pg->phys_addr |= __SHIFTIN(fl, UVM_PHYSADDR_FREELIST); 466 } 467 468 static inline void 469 uvm_page_set_bucket(struct vm_page *pg, unsigned b) 470 { 471 KASSERT(b < 32); 472 pg->phys_addr &= ~UVM_PHYSADDR_BUCKET; 473 pg->phys_addr |= __SHIFTIN(b, UVM_PHYSADDR_BUCKET); 474 } 475 476 #endif /* _KERNEL */ 477 478 #endif /* _UVM_UVM_PAGE_H_ */ 479
Indexes created Sat Sep 20 22:09:52 GMT 2025