proc->thread stage 4: rework the VFS and DEVICE subsystems to take thread
[dragonfly.git] / 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  * $FreeBSD: src/sys/vm/phys_pager.c,v 1.3.2.3 2000/12/17 02:05:41 alfred Exp $
26  * $DragonFly: src/sys/vm/phys_pager.c,v 1.2 2003/06/17 04:29:00 dillon Exp $
27  */
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/mman.h>
34 #include <sys/sysctl.h>
35
36 #include <vm/vm.h>
37 #include <vm/vm_object.h>
38 #include <vm/vm_page.h>
39 #include <vm/vm_pager.h>
40 #include <vm/vm_zone.h>
41
42 /* list of device pager objects */
43 static struct pagerlst phys_pager_object_list;
44
45 static int phys_pager_alloc_lock, phys_pager_alloc_lock_want;
46
47 static void
48 phys_pager_init(void)
49 {
50
51         TAILQ_INIT(&phys_pager_object_list);
52 }
53
54 static vm_object_t
55 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
56                  vm_ooffset_t foff)
57 {
58         vm_object_t object;
59
60         /*
61          * Offset should be page aligned.
62          */
63         if (foff & PAGE_MASK)
64                 return (NULL);
65
66         size = round_page(size);
67
68         if (handle != NULL) {
69                 /*
70                  * Lock to prevent object creation race condition.
71                  */
72                 while (phys_pager_alloc_lock) {
73                         phys_pager_alloc_lock_want++;
74                         tsleep(&phys_pager_alloc_lock, PVM, "ppall", 0);
75                         phys_pager_alloc_lock_want--;
76                 }
77                 phys_pager_alloc_lock = 1;
78         
79                 /*
80                  * Look up pager, creating as necessary.
81                  */
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                         object = vm_object_allocate(OBJT_PHYS,
88                                 OFF_TO_IDX(foff + size));
89                         object->handle = handle;
90                         TAILQ_INSERT_TAIL(&phys_pager_object_list, object,
91                             pager_object_list);
92                 } else {
93                         /*
94                          * Gain a reference to the object.
95                          */
96                         vm_object_reference(object);
97                         if (OFF_TO_IDX(foff + size) > object->size)
98                                 object->size = OFF_TO_IDX(foff + size);
99                 }
100                 phys_pager_alloc_lock = 0;
101                 if (phys_pager_alloc_lock_want)
102                         wakeup(&phys_pager_alloc_lock);
103         } else {
104                 object = vm_object_allocate(OBJT_PHYS,
105                         OFF_TO_IDX(foff + size));
106         }
107
108         return (object);
109 }
110
111 static void
112 phys_pager_dealloc(vm_object_t object)
113 {
114
115         if (object->handle != NULL)
116                 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list);
117 }
118
119 static int
120 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
121 {
122         int i, s;
123
124         s = splvm();
125         /*
126          * Fill as many pages as vm_fault has allocated for us.
127          */
128         for (i = 0; i < count; i++) {
129                 if ((m[i]->flags & PG_ZERO) == 0)
130                         vm_page_zero_fill(m[i]);
131                 vm_page_flag_set(m[i], PG_ZERO);
132                 /* Switch off pv_entries */
133                 vm_page_unmanage(m[i]);
134                 m[i]->valid = VM_PAGE_BITS_ALL;
135                 m[i]->dirty = 0;
136                 /* The requested page must remain busy, the others not. */
137                 if (reqpage != i) {
138                         vm_page_flag_clear(m[i], PG_BUSY);
139                         m[i]->busy = 0;
140                 }
141         }
142         splx(s);
143
144         return (VM_PAGER_OK);
145 }
146
147 static void
148 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync,
149                     int *rtvals)
150 {
151
152         panic("phys_pager_putpage called");
153 }
154
155 /*
156  * Implement a pretty aggressive clustered getpages strategy.  Hint that
157  * everything in an entire 4MB window should be prefaulted at once.
158  *
159  * XXX 4MB (1024 slots per page table page) is convenient for x86,
160  * but may not be for other arches.
161  */
162 #ifndef PHYSCLUSTER
163 #define PHYSCLUSTER 1024
164 #endif
165 static boolean_t
166 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
167                    int *after)
168 {
169         vm_pindex_t base, end;
170
171         base = pindex & (~(PHYSCLUSTER - 1));
172         end = base + (PHYSCLUSTER - 1);
173         if (before != NULL)
174                 *before = pindex - base;
175         if (after != NULL)
176                 *after = end - pindex;
177         return (TRUE);
178 }
179
180 struct pagerops physpagerops = {
181         phys_pager_init,
182         phys_pager_alloc,
183         phys_pager_dealloc,
184         phys_pager_getpages,
185         phys_pager_putpages,
186         phys_pager_haspage,
187         NULL
188 };