1 /* $NetBSD: uvm_page.h,v 1.80 2015/03/23 07:59:12 riastradh 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@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 #include <uvm/uvm_extern.h> 68 #include <uvm/uvm_pglist.h> 69 70 #include <sys/rbtree.h> 71 72 /* 73 * Management of resident (logical) pages. 74 * 75 * Each resident page has a vm_page structure, indexed by page number. 76 * There are several lists in the structure: 77 * 78 * - A red-black tree rooted with the containing object is used to 79 * quickly perform object+offset lookups. 80 * - A list of all pages for a given object, for a quick deactivation 81 * at a time of deallocation. 82 * - An ordered list of pages due for pageout. 83 * 84 * In addition, the structure contains the object and offset to which 85 * this page belongs (for pageout) and sundry status bits. 86 * 87 * Note that the page structure has no lock of its own. The page is 88 * generally protected by its owner's lock (UVM object or amap/anon). 89 * It should be noted that UVM has to serialize pmap(9) operations on 90 * the managed pages, e.g. for pmap_enter() calls. Hence, the lock 91 * order is as follows: 92 * 93 * [vmpage-owner-lock] -> 94 * any pmap locks (e.g. PV hash lock) 95 * 96 * Since the kernel is always self-consistent, no serialization is 97 * required for unmanaged mappings, e.g. for pmap_kenter_pa() calls. 98 * 99 * Field markings and the corresponding locks: 100 * 101 * f: free page queue lock, uvm_fpageqlock 102 * o: page owner (uvm_object::vmobjlock, vm_amap::am_lock, vm_anon::an_lock) 103 * p: page queue lock, uvm_pageqlock 104 * o,p: o|p for read, o&p for write 105 * w: wired page queue or uvm_pglistalloc: 106 * => wired page queue: o&p to change, stable from wire to unwire 107 * XXX What about concurrent or nested wire? 108 * => uvm_pglistalloc: owned by caller 109 * ?: locked by pmap or assumed page owner's lock 110 * 111 * UVM and pmap(9) may use uvm_page_locked_p() to assert whether the 112 * page owner's lock is acquired. 113 * 114 * A page can have one of four identities: 115 * 116 * o free 117 * => pageq.list is entry on global free page queue 118 * => listq.list is entry on per-CPU free page queue 119 * => uanon is unused (or (void *)0xdeadbeef for DEBUG) 120 * => uobject is unused (or (void *)0xdeadbeef for DEBUG) 121 * => PQ_FREE is set in pqflags 122 * o owned by a uvm_object 123 * => pageq.queue is entry on wired page queue, if any 124 * => listq.queue is entry on list of pages in object 125 * => uanon is NULL or the vm_anon to which it has been O->A loaned 126 * => uobject is owner 127 * o owned by a vm_anon 128 * => pageq is unused (XXX correct?) 129 * => listq is unused (XXX correct?) 130 * => uanon is owner 131 * => uobject is NULL 132 * => PQ_ANON is set in pqflags 133 * o allocated by uvm_pglistalloc 134 * => pageq.queue is entry on resulting pglist, owned by caller 135 * => listq is unused (XXX correct?) 136 * => uanon is unused 137 * => uobject is unused 138 * 139 * The following transitions are allowed: 140 * 141 * - uvm_pagealloc: free -> owned by a uvm_object/vm_anon 142 * - uvm_pagefree: owned by a uvm_object/vm_anon -> free 143 * - uvm_pglistalloc: free -> allocated by uvm_pglistalloc 144 * - uvm_pglistfree: allocated by uvm_pglistalloc -> free 145 */ 146 147 struct vm_page { 148 struct rb_node rb_node; /* o: tree of pages in obj */ 149 150 union { 151 TAILQ_ENTRY(vm_page) queue; /* w: wired page queue 152 * or uvm_pglistalloc output */ 153 LIST_ENTRY(vm_page) list; /* f: global free page queue */ 154 } pageq; 155 156 union { 157 TAILQ_ENTRY(vm_page) queue; /* o: pages in same object */ 158 LIST_ENTRY(vm_page) list; /* f: CPU free page queue */ 159 } listq; 160 161 struct vm_anon *uanon; /* o,p: anon */ 162 struct uvm_object *uobject; /* o,p: object */ 163 voff_t offset; /* o,p: offset into object */ 164 uint16_t flags; /* o: object flags */ 165 uint16_t loan_count; /* o,p: num. active loans */ 166 uint16_t wire_count; /* p: wired down map refs */ 167 uint16_t pqflags; /* p: page queue flags */ 168 paddr_t phys_addr; /* physical address of page */ 169 170 #ifdef __HAVE_VM_PAGE_MD 171 struct vm_page_md mdpage; /* ?: pmap-specific data */ 172 #endif 173 174 #if defined(UVM_PAGE_TRKOWN) 175 /* debugging fields to track page ownership */ 176 pid_t owner; /* proc that set PG_BUSY */ 177 lwpid_t lowner; /* lwp that set PG_BUSY */ 178 const char *owner_tag; /* why it was set busy */ 179 #endif 180 }; 181 182 /* 183 * Overview of UVM page flags. 184 * 185 * Locking notes: 186 * 187 * PG_, struct vm_page::flags => locked by owner 188 * PQ_, struct vm_page::pqflags => locked by uvm_pageqlock 189 * PQ_FREE => additionally locked by uvm_fpageqlock 190 * 191 * Flag descriptions: 192 * 193 * PG_BUSY: 194 * Page is long-term locked, usually because of I/O (transfer from the 195 * page memory to the backing store) is in progress. LWP attempting 196 * to access the page shall set PG_WANTED and wait. 197 * 198 * PG_WANTED: 199 * Indicates that the page, which is currently PG_BUSY, is wanted by 200 * some other LWP. The page owner (i.e. LWP which set PG_BUSY) is 201 * responsible to clear both flags and wake up any waiters once it has 202 * released the long-term lock (PG_BUSY). 203 * 204 * PG_RELEASED: 205 * Indicates that the page, which is currently PG_BUSY, should be freed 206 * after the release of long-term lock. It is responsibility of the 207 * owning LWP (i.e. which set PG_BUSY) to do it. 208 * 209 * PG_CLEAN: 210 * Page has not been modified since it was loaded from the backing 211 * store. If this flag is not set, page is considered "dirty". 212 * XXX: Currently it means that the page *might* be clean; will be 213 * fixed with yamt-pagecache merge. 214 * 215 * PG_FAKE: 216 * Page has been allocated, but not yet initialised. The flag is used 217 * to avoid overwriting of valid data, e.g. to prevent read from the 218 * backing store when in-core data is newer. 219 * 220 * PG_TABLED: 221 * Indicates that the page is currently in the object's offset queue, 222 * and that it should be removed from it once the page is freed. Used 223 * diagnostic purposes. 224 * 225 * PG_PAGEOUT: 226 * Indicates that the page is being paged-out in preparation for 227 * being freed. 228 * 229 * PG_RDONLY: 230 * Indicates that the page must be mapped read-only. 231 * 232 * PG_ZERO: 233 * Indicates that the page has been pre-zeroed. This flag is only 234 * set when the page is not in the queues and is cleared when the 235 * page is placed on the free list. 236 * 237 * PG_MARKER: 238 * Dummy marker page. 239 */ 240 241 #define PG_BUSY 0x0001 242 #define PG_WANTED 0x0002 243 #define PG_TABLED 0x0004 244 #define PG_CLEAN 0x0008 245 #define PG_PAGEOUT 0x0010 246 #define PG_RELEASED 0x0020 247 #define PG_FAKE 0x0040 248 #define PG_RDONLY 0x0080 249 #define PG_ZERO 0x0100 250 #define PG_MARKER 0x0200 251 252 #define PG_PAGER1 0x1000 /* pager-specific flag */ 253 254 #define UVM_PGFLAGBITS \ 255 "\20\1BUSY\2WANTED\3TABLED\4CLEAN\5PAGEOUT\6RELEASED\7FAKE\10RDONLY" \ 256 "\11ZERO\12MARKER\15PAGER1" 257 258 #define PQ_FREE 0x0001 /* page is on free list */ 259 #define PQ_ANON 0x0002 /* page is part of an anon, rather 260 than an uvm_object */ 261 #define PQ_AOBJ 0x0004 /* page is part of an anonymous 262 uvm_object */ 263 #define PQ_SWAPBACKED (PQ_ANON|PQ_AOBJ) 264 #define PQ_READAHEAD 0x0008 /* read-ahead but has not been "hit" yet */ 265 266 #define PQ_PRIVATE1 0x0100 267 #define PQ_PRIVATE2 0x0200 268 #define PQ_PRIVATE3 0x0400 269 #define PQ_PRIVATE4 0x0800 270 #define PQ_PRIVATE5 0x1000 271 #define PQ_PRIVATE6 0x2000 272 #define PQ_PRIVATE7 0x4000 273 #define PQ_PRIVATE8 0x8000 274 275 #define UVM_PQFLAGBITS \ 276 "\20\1FREE\2ANON\3AOBJ\4READAHEAD" \ 277 "\11PRIVATE1\12PRIVATE2\13PRIVATE3\14PRIVATE4" \ 278 "\15PRIVATE5\16PRIVATE6\17PRIVATE7\20PRIVATE8" 279 280 /* 281 * physical memory layout structure 282 * 283 * MD vmparam.h must #define: 284 * VM_PHYSEG_MAX = max number of physical memory segments we support 285 * (if this is "1" then we revert to a "contig" case) 286 * VM_PHYSSEG_STRAT: memory sort/search options (for VM_PHYSEG_MAX > 1) 287 * - VM_PSTRAT_RANDOM: linear search (random order) 288 * - VM_PSTRAT_BSEARCH: binary search (sorted by address) 289 * - VM_PSTRAT_BIGFIRST: linear search (sorted by largest segment first) 290 * - others? 291 * XXXCDC: eventually we should purge all left-over global variables... 292 */ 293 #define VM_PSTRAT_RANDOM 1 294 #define VM_PSTRAT_BSEARCH 2 295 #define VM_PSTRAT_BIGFIRST 3 296 297 /* 298 * vm_physseg: describes one segment of physical memory 299 */ 300 struct vm_physseg { 301 paddr_t start; /* PF# of first page in segment */ 302 paddr_t end; /* (PF# of last page in segment) + 1 */ 303 paddr_t avail_start; /* PF# of first free page in segment */ 304 paddr_t avail_end; /* (PF# of last free page in segment) +1 */ 305 struct vm_page *pgs; /* vm_page structures (from start) */ 306 struct vm_page *lastpg; /* vm_page structure for end */ 307 int free_list; /* which free list they belong on */ 308 u_int start_hint; /* start looking for free pages here */ 309 /* protected by uvm_fpageqlock */ 310 #ifdef __HAVE_PMAP_PHYSSEG 311 struct pmap_physseg pmseg; /* pmap specific (MD) data */ 312 #endif 313 }; 314 315 #ifdef _KERNEL 316 317 /* 318 * globals 319 */ 320 321 extern bool vm_page_zero_enable; 322 323 /* 324 * physical memory config is stored in vm_physmem. 325 */ 326 327 #define VM_PHYSMEM_PTR(i) (&vm_physmem[i]) 328 #if VM_PHYSSEG_MAX == 1 329 #define VM_PHYSMEM_PTR_SWAP(i, j) /* impossible */ 330 #else 331 #define VM_PHYSMEM_PTR_SWAP(i, j) \ 332 do { vm_physmem[(i)] = vm_physmem[(j)]; } while (0) 333 #endif 334 335 extern struct vm_physseg vm_physmem[VM_PHYSSEG_MAX]; 336 extern int vm_nphysseg; 337 338 /* 339 * prototypes: the following prototypes define the interface to pages 340 */ 341 342 void uvm_page_init(vaddr_t *, vaddr_t *); 343 #if defined(UVM_PAGE_TRKOWN) 344 void uvm_page_own(struct vm_page *, const char *); 345 #endif 346 #if !defined(PMAP_STEAL_MEMORY) 347 bool uvm_page_physget(paddr_t *); 348 #endif 349 void uvm_page_recolor(int); 350 void uvm_pageidlezero(void); 351 352 void uvm_pageactivate(struct vm_page *); 353 vaddr_t uvm_pageboot_alloc(vsize_t); 354 void uvm_pagecopy(struct vm_page *, struct vm_page *); 355 void uvm_pagedeactivate(struct vm_page *); 356 void uvm_pagedequeue(struct vm_page *); 357 void uvm_pageenqueue(struct vm_page *); 358 void uvm_pagefree(struct vm_page *); 359 void uvm_page_unbusy(struct vm_page **, int); 360 struct vm_page *uvm_pagelookup(struct uvm_object *, voff_t); 361 void uvm_pageunwire(struct vm_page *); 362 void uvm_pagewire(struct vm_page *); 363 void uvm_pagezero(struct vm_page *); 364 bool uvm_pageismanaged(paddr_t); 365 bool uvm_page_locked_p(struct vm_page *); 366 367 int uvm_page_lookup_freelist(struct vm_page *); 368 369 int vm_physseg_find(paddr_t, int *); 370 struct vm_page *uvm_phys_to_vm_page(paddr_t); 371 paddr_t uvm_vm_page_to_phys(const struct vm_page *); 372 373 /* 374 * macros 375 */ 376 377 #define UVM_PAGE_TREE_PENALTY 4 /* XXX: a guess */ 378 379 #define VM_PAGE_TO_PHYS(entry) uvm_vm_page_to_phys(entry) 380 381 #ifdef __HAVE_VM_PAGE_MD 382 #define VM_PAGE_TO_MD(pg) (&(pg)->mdpage) 383 #endif 384 385 /* 386 * Compute the page color bucket for a given page. 387 */ 388 #define VM_PGCOLOR_BUCKET(pg) \ 389 (atop(VM_PAGE_TO_PHYS((pg))) & uvmexp.colormask) 390 391 #define PHYS_TO_VM_PAGE(pa) uvm_phys_to_vm_page(pa) 392 393 #define VM_PAGE_IS_FREE(entry) ((entry)->pqflags & PQ_FREE) 394 #define VM_FREE_PAGE_TO_CPU(pg) ((struct uvm_cpu *)((uintptr_t)pg->offset)) 395 396 #ifdef DEBUG 397 void uvm_pagezerocheck(struct vm_page *); 398 #endif /* DEBUG */ 399 400 #endif /* _KERNEL */ 401 402 #endif /* _UVM_UVM_PAGE_H_ */ 403