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/conf.h> 32 #include <sys/kernel.h> 33 #include <sys/lock.h> 34 #include <sys/proc.h> 35 #include <sys/mutex.h> 36 #include <sys/mman.h> 37 #include <sys/rwlock.h> 38 #include <sys/sysctl.h> 39 40 #include <vm/vm.h> 41 #include <vm/vm_param.h> 42 #include <vm/vm_object.h> 43 #include <vm/vm_page.h> 44 #include <vm/vm_pager.h> 45 46 /* list of phys pager objects */ 47 static struct pagerlst phys_pager_object_list; 48 /* protect access to phys_pager_object_list */ 49 static struct mtx phys_pager_mtx; 50 51 static void 52 phys_pager_init(void) 53 { 54 55 TAILQ_INIT(&phys_pager_object_list); 56 mtx_init(&phys_pager_mtx, "phys_pager list", NULL, MTX_DEF); 57 } 58 59 static vm_object_t 60 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 61 vm_ooffset_t foff, struct ucred *cred) 62 { 63 vm_object_t object, object1; 64 vm_pindex_t pindex; 65 66 /* 67 * Offset should be page aligned. 68 */ 69 if (foff & PAGE_MASK) 70 return (NULL); 71 72 pindex = OFF_TO_IDX(foff + PAGE_MASK + size); 73 74 if (handle != NULL) { 75 mtx_lock(&phys_pager_mtx); 76 /* 77 * Look up pager, creating as necessary. 78 */ 79 object1 = NULL; 80 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 81 if (object == NULL) { 82 /* 83 * Allocate object and associate it with the pager. 84 */ 85 mtx_unlock(&phys_pager_mtx); 86 object1 = vm_object_allocate(OBJT_PHYS, pindex); 87 mtx_lock(&phys_pager_mtx); 88 object = vm_pager_object_lookup(&phys_pager_object_list, 89 handle); 90 if (object != NULL) { 91 /* 92 * We raced with other thread while 93 * allocating object. 94 */ 95 if (pindex > object->size) 96 object->size = pindex; 97 } else { 98 object = object1; 99 object1 = NULL; 100 object->handle = handle; 101 TAILQ_INSERT_TAIL(&phys_pager_object_list, 102 object, pager_object_list); 103 } 104 } else { 105 if (pindex > object->size) 106 object->size = pindex; 107 } 108 mtx_unlock(&phys_pager_mtx); 109 vm_object_deallocate(object1); 110 } else { 111 object = vm_object_allocate(OBJT_PHYS, pindex); 112 } 113 114 return (object); 115 } 116 117 static void 118 phys_pager_dealloc(vm_object_t object) 119 { 120 121 if (object->handle != NULL) { 122 VM_OBJECT_WUNLOCK(object); 123 mtx_lock(&phys_pager_mtx); 124 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 125 mtx_unlock(&phys_pager_mtx); 126 VM_OBJECT_WLOCK(object); 127 } 128 object->handle = NULL; 129 object->type = OBJT_DEAD; 130 } 131 132 /* 133 * Fill as many pages as vm_fault has allocated for us. 134 */ 135 static int 136 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind, 137 int *rahead) 138 { 139 int i; 140 141 VM_OBJECT_ASSERT_WLOCKED(object); 142 for (i = 0; i < count; i++) { 143 if (m[i]->valid == 0) { 144 if ((m[i]->flags & PG_ZERO) == 0) 145 pmap_zero_page(m[i]); 146 m[i]->valid = VM_PAGE_BITS_ALL; 147 } 148 KASSERT(m[i]->valid == VM_PAGE_BITS_ALL, 149 ("phys_pager_getpages: partially valid page %p", m[i])); 150 KASSERT(m[i]->dirty == 0, 151 ("phys_pager_getpages: dirty page %p", m[i])); 152 } 153 if (rbehind) 154 *rbehind = 0; 155 if (rahead) 156 *rahead = 0; 157 return (VM_PAGER_OK); 158 } 159 160 static void 161 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, 162 int *rtvals) 163 { 164 165 panic("phys_pager_putpage called"); 166 } 167 168 /* 169 * Implement a pretty aggressive clustered getpages strategy. Hint that 170 * everything in an entire 4MB window should be prefaulted at once. 171 * 172 * XXX 4MB (1024 slots per page table page) is convenient for x86, 173 * but may not be for other arches. 174 */ 175 #ifndef PHYSCLUSTER 176 #define PHYSCLUSTER 1024 177 #endif 178 static boolean_t 179 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 180 int *after) 181 { 182 vm_pindex_t base, end; 183 184 base = rounddown2(pindex, PHYSCLUSTER); 185 end = base + (PHYSCLUSTER - 1); 186 if (before != NULL) 187 *before = pindex - base; 188 if (after != NULL) 189 *after = end - pindex; 190 return (TRUE); 191 } 192 193 struct pagerops physpagerops = { 194 .pgo_init = phys_pager_init, 195 .pgo_alloc = phys_pager_alloc, 196 .pgo_dealloc = phys_pager_dealloc, 197 .pgo_getpages = phys_pager_getpages, 198 .pgo_putpages = phys_pager_putpages, 199 .pgo_haspage = phys_pager_haspage, 200 }; 201