FreeBSD/Linux Kernel Cross Reference
sys/vm/phys_pager.c
1 /*-
2 * Copyright (c) 2000 Peter Wemm
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/linker_set.h>
32 #include <sys/conf.h>
33 #include <sys/kernel.h>
34 #include <sys/lock.h>
35 #include <sys/proc.h>
36 #include <sys/mutex.h>
37 #include <sys/mman.h>
38 #include <sys/sysctl.h>
39
40 #include <vm/vm.h>
41 #include <vm/vm_object.h>
42 #include <vm/vm_page.h>
43 #include <vm/vm_pager.h>
44
45 /* list of phys pager objects */
46 static struct pagerlst phys_pager_object_list;
47 /* protect access to phys_pager_object_list */
48 static struct mtx phys_pager_mtx;
49
50 static void
51 phys_pager_init(void)
52 {
53
54 TAILQ_INIT(&phys_pager_object_list);
55 mtx_init(&phys_pager_mtx, "phys_pager list", NULL, MTX_DEF);
56 }
57
58 /*
59 * MPSAFE
60 */
61 static vm_object_t
62 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
63 vm_ooffset_t foff)
64 {
65 vm_object_t object, object1;
66 vm_pindex_t pindex;
67
68 /*
69 * Offset should be page aligned.
70 */
71 if (foff & PAGE_MASK)
72 return (NULL);
73
74 pindex = OFF_TO_IDX(foff + PAGE_MASK + size);
75
76 if (handle != NULL) {
77 mtx_lock(&phys_pager_mtx);
78 /*
79 * Look up pager, creating as necessary.
80 */
81 object1 = NULL;
82 object = vm_pager_object_lookup(&phys_pager_object_list, handle);
83 if (object == NULL) {
84 /*
85 * Allocate object and associate it with the pager.
86 */
87 mtx_unlock(&phys_pager_mtx);
88 object1 = vm_object_allocate(OBJT_PHYS, pindex);
89 mtx_lock(&phys_pager_mtx);
90 object = vm_pager_object_lookup(&phys_pager_object_list,
91 handle);
92 if (object != NULL) {
93 /*
94 * We raced with other thread while
95 * allocating object.
96 */
97 if (pindex > object->size)
98 object->size = pindex;
99 } else {
100 object = object1;
101 object1 = NULL;
102 object->handle = handle;
103 TAILQ_INSERT_TAIL(&phys_pager_object_list, object,
104 pager_object_list);
105 }
106 } else {
107 if (pindex > object->size)
108 object->size = pindex;
109 }
110 mtx_unlock(&phys_pager_mtx);
111 vm_object_deallocate(object1);
112 } else {
113 object = vm_object_allocate(OBJT_PHYS, pindex);
114 }
115
116 return (object);
117 }
118
119 /*
120 * MPSAFE
121 */
122 static void
123 phys_pager_dealloc(vm_object_t object)
124 {
125
126 if (object->handle != NULL) {
127 VM_OBJECT_UNLOCK(object);
128 mtx_lock(&phys_pager_mtx);
129 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list);
130 mtx_unlock(&phys_pager_mtx);
131 VM_OBJECT_LOCK(object);
132 }
133 }
134
135 /*
136 * Fill as many pages as vm_fault has allocated for us.
137 */
138 static int
139 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
140 {
141 int i;
142
143 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
144 for (i = 0; i < count; i++) {
145 if (m[i]->valid == 0) {
146 if ((m[i]->flags & PG_ZERO) == 0)
147 pmap_zero_page(m[i]);
148 m[i]->valid = VM_PAGE_BITS_ALL;
149 }
150 KASSERT(m[i]->valid == VM_PAGE_BITS_ALL,
151 ("phys_pager_getpages: partially valid page %p", m[i]));
152 m[i]->dirty = 0;
153 /* The requested page must remain busy, the others not. */
154 if (reqpage != i) {
155 m[i]->oflags &= ~VPO_BUSY;
156 m[i]->busy = 0;
157 }
158 }
159 return (VM_PAGER_OK);
160 }
161
162 static void
163 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync,
164 int *rtvals)
165 {
166
167 panic("phys_pager_putpage called");
168 }
169
170 /*
171 * Implement a pretty aggressive clustered getpages strategy. Hint that
172 * everything in an entire 4MB window should be prefaulted at once.
173 *
174 * XXX 4MB (1024 slots per page table page) is convenient for x86,
175 * but may not be for other arches.
176 */
177 #ifndef PHYSCLUSTER
178 #define PHYSCLUSTER 1024
179 #endif
180 static boolean_t
181 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
182 int *after)
183 {
184 vm_pindex_t base, end;
185
186 base = pindex & (~(PHYSCLUSTER - 1));
187 end = base + (PHYSCLUSTER - 1);
188 if (before != NULL)
189 *before = pindex - base;
190 if (after != NULL)
191 *after = end - pindex;
192 return (TRUE);
193 }
194
195 struct pagerops physpagerops = {
196 .pgo_init = phys_pager_init,
197 .pgo_alloc = phys_pager_alloc,
198 .pgo_dealloc = phys_pager_dealloc,
199 .pgo_getpages = phys_pager_getpages,
200 .pgo_putpages = phys_pager_putpages,
201 .pgo_haspage = phys_pager_haspage,
202 };
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