FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_pager.h
1 /*-
2 * Copyright (c) 1990 University of Utah.
3 * Copyright (c) 1991, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * the Systems Programming Group of the University of Utah Computer
8 * Science Department.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)vm_pager.h 8.4 (Berkeley) 1/12/94
35 * $FreeBSD$
36 */
37
38 /*
39 * Pager routine interface definition.
40 */
41
42 #ifndef _VM_PAGER_
43 #define _VM_PAGER_
44
45 #include <sys/queue.h>
46
47 TAILQ_HEAD(pagerlst, vm_object);
48
49 struct bio;
50
51 typedef void pgo_init_t(void);
52 typedef vm_object_t pgo_alloc_t(void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t);
53 typedef void pgo_dealloc_t(vm_object_t);
54 typedef int pgo_getpages_t(vm_object_t, vm_page_t *, int, int);
55 typedef void pgo_putpages_t(vm_object_t, vm_page_t *, int, int, int *);
56 typedef boolean_t pgo_haspage_t(vm_object_t, vm_pindex_t, int *, int *);
57 typedef void pgo_pageunswapped_t(vm_page_t);
58
59 struct pagerops {
60 pgo_init_t *pgo_init; /* Initialize pager. */
61 pgo_alloc_t *pgo_alloc; /* Allocate pager. */
62 pgo_dealloc_t *pgo_dealloc; /* Disassociate. */
63 pgo_getpages_t *pgo_getpages; /* Get (read) page. */
64 pgo_putpages_t *pgo_putpages; /* Put (write) page. */
65 pgo_haspage_t *pgo_haspage; /* Does pager have page? */
66 pgo_pageunswapped_t *pgo_pageunswapped;
67 };
68
69 extern struct pagerops defaultpagerops;
70 extern struct pagerops swappagerops;
71 extern struct pagerops vnodepagerops;
72 extern struct pagerops devicepagerops;
73 extern struct pagerops physpagerops;
74
75 /*
76 * get/put return values
77 * OK operation was successful
78 * BAD specified data was out of the accepted range
79 * FAIL specified data was in range, but doesn't exist
80 * PEND operations was initiated but not completed
81 * ERROR error while accessing data that is in range and exists
82 * AGAIN temporary resource shortage prevented operation from happening
83 */
84 #define VM_PAGER_OK 0
85 #define VM_PAGER_BAD 1
86 #define VM_PAGER_FAIL 2
87 #define VM_PAGER_PEND 3
88 #define VM_PAGER_ERROR 4
89 #define VM_PAGER_AGAIN 5
90
91 #define VM_PAGER_PUT_SYNC 0x0001
92 #define VM_PAGER_PUT_INVAL 0x0002
93 #define VM_PAGER_IGNORE_CLEANCHK 0x0004
94 #define VM_PAGER_CLUSTER_OK 0x0008
95
96 #ifdef _KERNEL
97 #ifdef MALLOC_DECLARE
98 MALLOC_DECLARE(M_VMPGDATA);
99 #endif
100
101 extern vm_map_t pager_map;
102 extern struct pagerops *pagertab[];
103 extern struct mtx pbuf_mtx;
104
105 vm_object_t vm_pager_allocate(objtype_t, void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t);
106 void vm_pager_bufferinit(void);
107 void vm_pager_deallocate(vm_object_t);
108 static __inline int vm_pager_get_pages(vm_object_t, vm_page_t *, int, int);
109 static __inline boolean_t vm_pager_has_page(vm_object_t, vm_pindex_t, int *, int *);
110 void vm_pager_init(void);
111 vm_object_t vm_pager_object_lookup(struct pagerlst *, void *);
112
113 /*
114 * vm_page_get_pages:
115 *
116 * Retrieve pages from the VM system in order to map them into an object
117 * ( or into VM space somewhere ). If the pagein was successful, we
118 * must fully validate it.
119 */
120 static __inline int
121 vm_pager_get_pages(
122 vm_object_t object,
123 vm_page_t *m,
124 int count,
125 int reqpage
126 ) {
127 int r;
128
129 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
130 r = (*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage);
131 if (r == VM_PAGER_OK && m[reqpage]->valid != VM_PAGE_BITS_ALL) {
132 vm_page_zero_invalid(m[reqpage], TRUE);
133 }
134 return (r);
135 }
136
137 static __inline void
138 vm_pager_put_pages(
139 vm_object_t object,
140 vm_page_t *m,
141 int count,
142 int flags,
143 int *rtvals
144 ) {
145
146 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
147 (*pagertab[object->type]->pgo_putpages)
148 (object, m, count, flags, rtvals);
149 }
150
151 /*
152 * vm_pager_haspage
153 *
154 * Check to see if an object's pager has the requested page. The
155 * object's pager will also set before and after to give the caller
156 * some idea of the number of pages before and after the requested
157 * page can be I/O'd efficiently.
158 *
159 * The object must be locked.
160 */
161 static __inline boolean_t
162 vm_pager_has_page(
163 vm_object_t object,
164 vm_pindex_t offset,
165 int *before,
166 int *after
167 ) {
168 boolean_t ret;
169
170 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
171 ret = (*pagertab[object->type]->pgo_haspage)
172 (object, offset, before, after);
173 return (ret);
174 }
175
176 /*
177 * vm_pager_page_unswapped
178 *
179 * Destroy swap associated with the page.
180 *
181 * The object containing the page must be locked.
182 * This function may not block.
183 *
184 * XXX: A much better name would be "vm_pager_page_dirtied()"
185 * XXX: It is not obvious if this could be profitably used by any
186 * XXX: pagers besides the swap_pager or if it should even be a
187 * XXX: generic pager_op in the first place.
188 */
189 static __inline void
190 vm_pager_page_unswapped(vm_page_t m)
191 {
192
193 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
194 if (pagertab[m->object->type]->pgo_pageunswapped)
195 (*pagertab[m->object->type]->pgo_pageunswapped)(m);
196 }
197
198 #endif /* _KERNEL */
199 #endif /* _VM_PAGER_ */
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