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: releng/7.4/sys/vm/vm_pager.h 197197 2009-09-14 17:34:49Z jhb $
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 extern struct pagerops sgpagerops;
75
76 /*
77 * get/put return values
78 * OK operation was successful
79 * BAD specified data was out of the accepted range
80 * FAIL specified data was in range, but doesn't exist
81 * PEND operations was initiated but not completed
82 * ERROR error while accessing data that is in range and exists
83 * AGAIN temporary resource shortage prevented operation from happening
84 */
85 #define VM_PAGER_OK 0
86 #define VM_PAGER_BAD 1
87 #define VM_PAGER_FAIL 2
88 #define VM_PAGER_PEND 3
89 #define VM_PAGER_ERROR 4
90 #define VM_PAGER_AGAIN 5
91
92 #define VM_PAGER_PUT_SYNC 0x0001
93 #define VM_PAGER_PUT_INVAL 0x0002
94 #define VM_PAGER_IGNORE_CLEANCHK 0x0004
95 #define VM_PAGER_CLUSTER_OK 0x0008
96
97 #ifdef _KERNEL
98 #ifdef MALLOC_DECLARE
99 MALLOC_DECLARE(M_VMPGDATA);
100 #endif
101
102 extern vm_map_t pager_map;
103 extern struct pagerops *pagertab[];
104 extern struct mtx pbuf_mtx;
105
106 vm_object_t vm_pager_allocate(objtype_t, void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t);
107 void vm_pager_bufferinit(void);
108 void vm_pager_deallocate(vm_object_t);
109 static __inline int vm_pager_get_pages(vm_object_t, vm_page_t *, int, int);
110 static __inline boolean_t vm_pager_has_page(vm_object_t, vm_pindex_t, int *, int *);
111 void vm_pager_init(void);
112 vm_object_t vm_pager_object_lookup(struct pagerlst *, void *);
113
114 /*
115 * vm_page_get_pages:
116 *
117 * Retrieve pages from the VM system in order to map them into an object
118 * ( or into VM space somewhere ). If the pagein was successful, we
119 * must fully validate it.
120 */
121 static __inline int
122 vm_pager_get_pages(
123 vm_object_t object,
124 vm_page_t *m,
125 int count,
126 int reqpage
127 ) {
128 int r;
129
130 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
131 r = (*pagertab[object->type]->pgo_getpages)(object, m, count, reqpage);
132 if (r == VM_PAGER_OK && m[reqpage]->valid != VM_PAGE_BITS_ALL) {
133 vm_page_zero_invalid(m[reqpage], TRUE);
134 }
135 return (r);
136 }
137
138 static __inline void
139 vm_pager_put_pages(
140 vm_object_t object,
141 vm_page_t *m,
142 int count,
143 int flags,
144 int *rtvals
145 ) {
146
147 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
148 (*pagertab[object->type]->pgo_putpages)
149 (object, m, count, flags, rtvals);
150 }
151
152 /*
153 * vm_pager_haspage
154 *
155 * Check to see if an object's pager has the requested page. The
156 * object's pager will also set before and after to give the caller
157 * some idea of the number of pages before and after the requested
158 * page can be I/O'd efficiently.
159 *
160 * The object must be locked.
161 */
162 static __inline boolean_t
163 vm_pager_has_page(
164 vm_object_t object,
165 vm_pindex_t offset,
166 int *before,
167 int *after
168 ) {
169 boolean_t ret;
170
171 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
172 ret = (*pagertab[object->type]->pgo_haspage)
173 (object, offset, before, after);
174 return (ret);
175 }
176
177 /*
178 * vm_pager_page_unswapped
179 *
180 * Destroy swap associated with the page.
181 *
182 * The object containing the page must be locked.
183 * This function may not block.
184 *
185 * XXX: A much better name would be "vm_pager_page_dirtied()"
186 * XXX: It is not obvious if this could be profitably used by any
187 * XXX: pagers besides the swap_pager or if it should even be a
188 * XXX: generic pager_op in the first place.
189 */
190 static __inline void
191 vm_pager_page_unswapped(vm_page_t m)
192 {
193
194 VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
195 if (pagertab[m->object->type]->pgo_pageunswapped)
196 (*pagertab[m->object->type]->pgo_pageunswapped)(m);
197 }
198
199 #endif /* _KERNEL */
200 #endif /* _VM_PAGER_ */
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