2 * Copyright (c) 2000 Peter Wemm
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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.
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
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 1.3 2003/07/19 21:14:53 dillon Exp $
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/linker_set.h>
34 #include <sys/sysctl.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>
42 /* list of device pager objects */
43 static struct pagerlst phys_pager_object_list;
45 static int phys_pager_alloc_lock, phys_pager_alloc_lock_want;
51 TAILQ_INIT(&phys_pager_object_list);
55 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
61 * Offset should be page aligned.
66 size = round_page(size);
70 * Lock to prevent object creation race condition.
72 while (phys_pager_alloc_lock) {
73 phys_pager_alloc_lock_want++;
74 tsleep(&phys_pager_alloc_lock, 0, "ppall", 0);
75 phys_pager_alloc_lock_want--;
77 phys_pager_alloc_lock = 1;
80 * Look up pager, creating as necessary.
82 object = vm_pager_object_lookup(&phys_pager_object_list, handle);
85 * Allocate object and associate it with the pager.
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,
94 * Gain a reference to the object.
96 vm_object_reference(object);
97 if (OFF_TO_IDX(foff + size) > object->size)
98 object->size = OFF_TO_IDX(foff + size);
100 phys_pager_alloc_lock = 0;
101 if (phys_pager_alloc_lock_want)
102 wakeup(&phys_pager_alloc_lock);
104 object = vm_object_allocate(OBJT_PHYS,
105 OFF_TO_IDX(foff + size));
112 phys_pager_dealloc(vm_object_t object)
115 if (object->handle != NULL)
116 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list);
120 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
126 * Fill as many pages as vm_fault has allocated for us.
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;
136 /* The requested page must remain busy, the others not. */
138 vm_page_flag_clear(m[i], PG_BUSY);
144 return (VM_PAGER_OK);
148 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync,
152 panic("phys_pager_putpage called");
156 * Implement a pretty aggressive clustered getpages strategy. Hint that
157 * everything in an entire 4MB window should be prefaulted at once.
159 * XXX 4MB (1024 slots per page table page) is convenient for x86,
160 * but may not be for other arches.
163 #define PHYSCLUSTER 1024
166 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
169 vm_pindex_t base, end;
171 base = pindex & (~(PHYSCLUSTER - 1));
172 end = base + (PHYSCLUSTER - 1);
174 *before = pindex - base;
176 *after = end - pindex;
180 struct pagerops physpagerops = {