1 /* $NetBSD: uvm_page.h,v 1.76 2013/10/25 14:30:21 martin 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 * o: page owner's lock (UVM object or amap/anon) 102 * p: lock on the page queues 103 * o|p: either lock can be acquired 104 * o&p: both locks are required 105 * ?: locked by pmap or assumed page owner's lock 106 * 107 * UVM and pmap(9) may use uvm_page_locked_p() to assert whether the 108 * page owner's lock is acquired. 109 */ 110 111 struct vm_page { 112 struct rb_node rb_node; /* o: tree of pages in obj */ 113 114 union { 115 TAILQ_ENTRY(vm_page) queue; 116 LIST_ENTRY(vm_page) list; 117 } pageq; /* p: queue info for FIFO 118 * queue or free list */ 119 union { 120 TAILQ_ENTRY(vm_page) queue; 121 LIST_ENTRY(vm_page) list; 122 } listq; /* o: pages in same object */ 123 124 struct vm_anon *uanon; /* o,p: anon */ 125 struct uvm_object *uobject; /* o,p: object */ 126 voff_t offset; /* o,p: offset into object */ 127 uint16_t flags; /* o: object flags */ 128 uint16_t loan_count; /* number of active loans 129 * o|p: for reading 130 * o&p: for modification */ 131 uint16_t wire_count; /* p: wired down map refs */ 132 uint16_t pqflags; /* p: page queue flags */ 133 paddr_t phys_addr; /* physical address of page */ 134 135 #ifdef __HAVE_VM_PAGE_MD 136 struct vm_page_md mdpage; /* ?: pmap-specific data */ 137 #endif 138 139 #if defined(UVM_PAGE_TRKOWN) 140 /* debugging fields to track page ownership */ 141 pid_t owner; /* proc that set PG_BUSY */ 142 lwpid_t lowner; /* lwp that set PG_BUSY */ 143 const char *owner_tag; /* why it was set busy */ 144 #endif 145 }; 146 147 /* 148 * Overview of UVM page flags. 149 * 150 * Locking notes: 151 * 152 * PG_, struct vm_page::flags => locked by the owner 153 * PQ_, struct vm_page::pqflags => locked by the page-queue lock 154 * PQ_FREE => additionally locked by free-queue lock 155 * 156 * Flag descriptions: 157 * 158 * PG_BUSY: 159 * Page is long-term locked, usually because of I/O (transfer from the 160 * page memory to the backing store) is in progress. LWP attempting 161 * to access the page shall set PG_WANTED and wait. 162 * 163 * PG_WANTED: 164 * Indicates that the page, which is currently PG_BUSY, is wanted by 165 * some other LWP. The page owner (i.e. LWP which set PG_BUSY) is 166 * responsible to clear both flags and wake up any waiters once it has 167 * released the long-term lock (PG_BUSY). 168 * 169 * PG_RELEASED: 170 * Indicates that the page, which is currently PG_BUSY, should be freed 171 * after the release of long-term lock. It is responsibility of the 172 * owning LWP (i.e. which set PG_BUSY) to do it. 173 * 174 * PG_CLEAN: 175 * Page has not been modified since it was loaded from the backing 176 * store. If this flag is not set, page is considered "dirty". 177 * XXX: Currently it means that the page *might* be clean; will be 178 * fixed with yamt-pagecache merge. 179 * 180 * PG_FAKE: 181 * Page has been allocated, but not yet initialised. The flag is used 182 * to avoid overwriting of valid data, e.g. to prevent read from the 183 * backing store when in-core data is newer. 184 * 185 * PG_TABLED: 186 * Indicates that the page is currently in the object's offset queue, 187 * and that it should be removed from it once the page is freed. Used 188 * diagnostic purposes. 189 * 190 * PG_PAGEOUT: 191 * Indicates that the page is being paged-out in preparation for 192 * being freed. 193 * 194 * PG_RDONLY: 195 * Indicates that the page must be mapped read-only. 196 * 197 * PG_ZERO: 198 * Indicates that the page has been pre-zeroed. This flag is only 199 * set when the page is not in the queues and is cleared when the 200 * page is placed on the free list. 201 * 202 * PG_MARKER: 203 * Dummy marker page. 204 */ 205 206 #define PG_BUSY 0x0001 207 #define PG_WANTED 0x0002 208 #define PG_TABLED 0x0004 209 #define PG_CLEAN 0x0008 210 #define PG_PAGEOUT 0x0010 211 #define PG_RELEASED 0x0020 212 #define PG_FAKE 0x0040 213 #define PG_RDONLY 0x0080 214 #define PG_ZERO 0x0100 215 #define PG_MARKER 0x0200 216 217 #define PG_PAGER1 0x1000 /* pager-specific flag */ 218 219 #define UVM_PGFLAGBITS \ 220 "\20\1BUSY\2WANTED\3TABLED\4CLEAN\5PAGEOUT\6RELEASED\7FAKE\10RDONLY" \ 221 "\11ZERO\12MARKER\15PAGER1" 222 223 #define PQ_FREE 0x0001 /* page is on free list */ 224 #define PQ_ANON 0x0002 /* page is part of an anon, rather 225 than an uvm_object */ 226 #define PQ_AOBJ 0x0004 /* page is part of an anonymous 227 uvm_object */ 228 #define PQ_SWAPBACKED (PQ_ANON|PQ_AOBJ) 229 #define PQ_READAHEAD 0x0008 /* read-ahead but has not been "hit" yet */ 230 231 #define PQ_PRIVATE1 0x0100 232 #define PQ_PRIVATE2 0x0200 233 #define PQ_PRIVATE3 0x0400 234 #define PQ_PRIVATE4 0x0800 235 #define PQ_PRIVATE5 0x1000 236 #define PQ_PRIVATE6 0x2000 237 #define PQ_PRIVATE7 0x4000 238 #define PQ_PRIVATE8 0x8000 239 240 #define UVM_PQFLAGBITS \ 241 "\20\1FREE\2ANON\3AOBJ\4READAHEAD" \ 242 "\11PRIVATE1\12PRIVATE2\13PRIVATE3\14PRIVATE4" \ 243 "\15PRIVATE5\16PRIVATE6\17PRIVATE7\20PRIVATE8" 244 245 /* 246 * physical memory layout structure 247 * 248 * MD vmparam.h must #define: 249 * VM_PHYSEG_MAX = max number of physical memory segments we support 250 * (if this is "1" then we revert to a "contig" case) 251 * VM_PHYSSEG_STRAT: memory sort/search options (for VM_PHYSEG_MAX > 1) 252 * - VM_PSTRAT_RANDOM: linear search (random order) 253 * - VM_PSTRAT_BSEARCH: binary search (sorted by address) 254 * - VM_PSTRAT_BIGFIRST: linear search (sorted by largest segment first) 255 * - others? 256 * XXXCDC: eventually we should purge all left-over global variables... 257 */ 258 #define VM_PSTRAT_RANDOM 1 259 #define VM_PSTRAT_BSEARCH 2 260 #define VM_PSTRAT_BIGFIRST 3 261 262 /* 263 * vm_physseg: describes one segment of physical memory 264 */ 265 struct vm_physseg { 266 paddr_t start; /* PF# of first page in segment */ 267 paddr_t end; /* (PF# of last page in segment) + 1 */ 268 paddr_t avail_start; /* PF# of first free page in segment */ 269 paddr_t avail_end; /* (PF# of last free page in segment) +1 */ 270 struct vm_page *pgs; /* vm_page structures (from start) */ 271 struct vm_page *lastpg; /* vm_page structure for end */ 272 int free_list; /* which free list they belong on */ 273 u_int start_hint; /* start looking for free pages here */ 274 /* protected by uvm_fpageqlock */ 275 #ifdef __HAVE_PMAP_PHYSSEG 276 struct pmap_physseg pmseg; /* pmap specific (MD) data */ 277 #endif 278 }; 279 280 #ifdef _KERNEL 281 282 /* 283 * globals 284 */ 285 286 extern bool vm_page_zero_enable; 287 288 /* 289 * physical memory config is stored in vm_physmem. 290 */ 291 292 #define VM_PHYSMEM_PTR(i) (&vm_physmem[i]) 293 #if VM_PHYSSEG_MAX == 1 294 #define VM_PHYSMEM_PTR_SWAP(i, j) /* impossible */ 295 #else 296 #define VM_PHYSMEM_PTR_SWAP(i, j) \ 297 do { vm_physmem[(i)] = vm_physmem[(j)]; } while (0) 298 #endif 299 300 extern struct vm_physseg vm_physmem[VM_PHYSSEG_MAX]; 301 extern int vm_nphysseg; 302 303 /* 304 * prototypes: the following prototypes define the interface to pages 305 */ 306 307 void uvm_page_init(vaddr_t *, vaddr_t *); 308 #if defined(UVM_PAGE_TRKOWN) 309 void uvm_page_own(struct vm_page *, const char *); 310 #endif 311 #if !defined(PMAP_STEAL_MEMORY) 312 bool uvm_page_physget(paddr_t *); 313 #endif 314 void uvm_page_recolor(int); 315 void uvm_pageidlezero(void); 316 317 void uvm_pageactivate(struct vm_page *); 318 vaddr_t uvm_pageboot_alloc(vsize_t); 319 void uvm_pagecopy(struct vm_page *, struct vm_page *); 320 void uvm_pagedeactivate(struct vm_page *); 321 void uvm_pagedequeue(struct vm_page *); 322 void uvm_pageenqueue(struct vm_page *); 323 void uvm_pagefree(struct vm_page *); 324 void uvm_page_unbusy(struct vm_page **, int); 325 struct vm_page *uvm_pagelookup(struct uvm_object *, voff_t); 326 void uvm_pageunwire(struct vm_page *); 327 void uvm_pagewire(struct vm_page *); 328 void uvm_pagezero(struct vm_page *); 329 bool uvm_pageismanaged(paddr_t); 330 bool uvm_page_locked_p(struct vm_page *); 331 332 int uvm_page_lookup_freelist(struct vm_page *); 333 334 int vm_physseg_find(paddr_t, int *); 335 struct vm_page *uvm_phys_to_vm_page(paddr_t); 336 paddr_t uvm_vm_page_to_phys(const struct vm_page *); 337 338 /* 339 * macros 340 */ 341 342 #define UVM_PAGE_TREE_PENALTY 4 /* XXX: a guess */ 343 344 #define VM_PAGE_TO_PHYS(entry) uvm_vm_page_to_phys(entry) 345 346 #ifdef __HAVE_VM_PAGE_MD 347 #define VM_PAGE_TO_MD(pg) (&(pg)->mdpage) 348 #endif 349 350 /* 351 * Compute the page color bucket for a given page. 352 */ 353 #define VM_PGCOLOR_BUCKET(pg) \ 354 (atop(VM_PAGE_TO_PHYS((pg))) & uvmexp.colormask) 355 356 #define PHYS_TO_VM_PAGE(pa) uvm_phys_to_vm_page(pa) 357 358 #define VM_PAGE_IS_FREE(entry) ((entry)->pqflags & PQ_FREE) 359 #define VM_FREE_PAGE_TO_CPU(pg) ((struct uvm_cpu *)((uintptr_t)pg->offset)) 360 361 #ifdef DEBUG 362 void uvm_pagezerocheck(struct vm_page *); 363 #endif /* DEBUG */ 364 365 #endif /* _KERNEL */ 366 367 #endif /* _UVM_UVM_PAGE_H_ */ 368