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
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/linker_set.h>
33 #include <sys/kernel.h>
36 #include <sys/mutex.h>
38 #include <sys/sysctl.h>
41 #include <vm/vm_object.h>
42 #include <vm/vm_page.h>
43 #include <vm/vm_pager.h>
45 /* prevent concurrant creation races */
46 static int phys_pager_alloc_lock;
47 /* list of device pager objects */
48 static struct pagerlst phys_pager_object_list;
49 /* protect access to phys_pager_object_list */
50 static struct mtx phys_pager_mtx;
56 TAILQ_INIT(&phys_pager_object_list);
57 mtx_init(&phys_pager_mtx, "phys_pager list", NULL, MTX_DEF);
64 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
71 * Offset should be page aligned.
76 pindex = OFF_TO_IDX(foff + PAGE_MASK + size);
81 * Lock to prevent object creation race condition.
83 while (phys_pager_alloc_lock) {
84 phys_pager_alloc_lock = -1;
85 tsleep(&phys_pager_alloc_lock, PVM, "swpalc", 0);
87 phys_pager_alloc_lock = 1;
90 * Look up pager, creating as necessary.
92 object = vm_pager_object_lookup(&phys_pager_object_list, handle);
95 * Allocate object and associate it with the pager.
97 object = vm_object_allocate(OBJT_PHYS, pindex);
98 object->handle = handle;
99 mtx_lock(&phys_pager_mtx);
100 TAILQ_INSERT_TAIL(&phys_pager_object_list, object,
102 mtx_unlock(&phys_pager_mtx);
105 * Gain a reference to the object.
107 vm_object_reference(object);
108 if (pindex > object->size)
109 object->size = pindex;
111 if (phys_pager_alloc_lock == -1)
112 wakeup(&phys_pager_alloc_lock);
113 phys_pager_alloc_lock = 0;
116 object = vm_object_allocate(OBJT_PHYS, pindex);
126 phys_pager_dealloc(vm_object_t object)
129 if (object->handle != NULL) {
130 mtx_lock(&phys_pager_mtx);
131 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list);
132 mtx_unlock(&phys_pager_mtx);
137 * Fill as many pages as vm_fault has allocated for us.
140 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
144 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
145 for (i = 0; i < count; i++) {
146 if (m[i]->valid == 0) {
147 if ((m[i]->flags & PG_ZERO) == 0)
148 pmap_zero_page(m[i]);
149 m[i]->valid = VM_PAGE_BITS_ALL;
151 KASSERT(m[i]->valid == VM_PAGE_BITS_ALL,
152 ("phys_pager_getpages: partially valid page %p", m[i]));
154 vm_page_lock_queues();
155 for (i = 0; i < count; i++) {
156 /* Switch off pv_entries */
157 vm_page_unmanage(m[i]);
159 /* The requested page must remain busy, the others not. */
161 vm_page_flag_clear(m[i], PG_BUSY);
165 vm_page_unlock_queues();
166 return (VM_PAGER_OK);
170 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync,
174 panic("phys_pager_putpage called");
178 * Implement a pretty aggressive clustered getpages strategy. Hint that
179 * everything in an entire 4MB window should be prefaulted at once.
181 * XXX 4MB (1024 slots per page table page) is convenient for x86,
182 * but may not be for other arches.
185 #define PHYSCLUSTER 1024
188 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
191 vm_pindex_t base, end;
193 base = pindex & (~(PHYSCLUSTER - 1));
194 end = base + (PHYSCLUSTER - 1);
196 *before = pindex - base;
198 *after = end - pindex;
202 struct pagerops physpagerops = {
203 .pgo_init = phys_pager_init,
204 .pgo_alloc = phys_pager_alloc,
205 .pgo_dealloc = phys_pager_dealloc,
206 .pgo_getpages = phys_pager_getpages,
207 .pgo_putpages = phys_pager_putpages,
208 .pgo_haspage = phys_pager_haspage,