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
147struct 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 */
300struct 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
321extern 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
335extern struct vm_physseg vm_physmem[VM_PHYSSEG_MAX];
336extern int vm_nphysseg;
337
338/*
339 * prototypes: the following prototypes define the interface to pages
340 */
341
342void uvm_page_init(vaddr_t *, vaddr_t *);
343#if defined(UVM_PAGE_TRKOWN)
344void uvm_page_own(struct vm_page *, const char *);
345#endif
346#if !defined(PMAP_STEAL_MEMORY)
347bool uvm_page_physget(paddr_t *);
348#endif
349void uvm_page_recolor(int);
350void uvm_pageidlezero(void);
351
352void uvm_pageactivate(struct vm_page *);
353vaddr_t uvm_pageboot_alloc(vsize_t);
354void uvm_pagecopy(struct vm_page *, struct vm_page *);
355void uvm_pagedeactivate(struct vm_page *);
356void uvm_pagedequeue(struct vm_page *);
357void uvm_pageenqueue(struct vm_page *);
358void uvm_pagefree(struct vm_page *);
359void uvm_page_unbusy(struct vm_page **, int);
360struct vm_page *uvm_pagelookup(struct uvm_object *, voff_t);
361void uvm_pageunwire(struct vm_page *);
362void uvm_pagewire(struct vm_page *);
363void uvm_pagezero(struct vm_page *);
364bool uvm_pageismanaged(paddr_t);
365bool uvm_page_locked_p(struct vm_page *);
366
367int uvm_page_lookup_freelist(struct vm_page *);
368
369int vm_physseg_find(paddr_t, int *);
370struct vm_page *uvm_phys_to_vm_page(paddr_t);
371paddr_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
397void uvm_pagezerocheck(struct vm_page *);
398#endif /* DEBUG */
399
400#endif /* _KERNEL */
401
402#endif /* _UVM_UVM_PAGE_H_ */
403