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_pageout.h> 45 #include <vm/vm_pager.h> 46 47 /* list of phys 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; 51 52 static void 53 phys_pager_init(void) 54 { 55 56 TAILQ_INIT(&phys_pager_object_list); 57 mtx_init(&phys_pager_mtx, "phys_pager list", NULL, MTX_DEF); 58 } 59 60 static vm_object_t 61 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 62 vm_ooffset_t foff, struct ucred *cred) 63 { 64 vm_object_t object, object1; 65 vm_pindex_t pindex; 66 67 /* 68 * Offset should be page aligned. 69 */ 70 if (foff & PAGE_MASK) 71 return (NULL); 72 73 pindex = OFF_TO_IDX(foff + PAGE_MASK + size); 74 75 if (handle != NULL) { 76 mtx_lock(&phys_pager_mtx); 77 /* 78 * Look up pager, creating as necessary. 79 */ 80 object1 = NULL; 81 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 82 if (object == NULL) { 83 /* 84 * Allocate object and associate it with the pager. 85 */ 86 mtx_unlock(&phys_pager_mtx); 87 object1 = vm_object_allocate(OBJT_PHYS, pindex); 88 mtx_lock(&phys_pager_mtx); 89 object = vm_pager_object_lookup(&phys_pager_object_list, 90 handle); 91 if (object != NULL) { 92 /* 93 * We raced with other thread while 94 * allocating object. 95 */ 96 if (pindex > object->size) 97 object->size = pindex; 98 } else { 99 object = object1; 100 object1 = NULL; 101 object->handle = handle; 102 vm_object_set_flag(object, OBJ_POPULATE); 103 TAILQ_INSERT_TAIL(&phys_pager_object_list, 104 object, 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 vm_object_set_flag(object, OBJ_POPULATE); 115 } 116 117 return (object); 118 } 119 120 static void 121 phys_pager_dealloc(vm_object_t object) 122 { 123 124 if (object->handle != NULL) { 125 VM_OBJECT_WUNLOCK(object); 126 mtx_lock(&phys_pager_mtx); 127 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 128 mtx_unlock(&phys_pager_mtx); 129 VM_OBJECT_WLOCK(object); 130 } 131 object->handle = NULL; 132 object->type = OBJT_DEAD; 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 *rbehind, 140 int *rahead) 141 { 142 int i; 143 144 VM_OBJECT_ASSERT_WLOCKED(object); 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; 150 } 151 KASSERT(m[i]->valid == VM_PAGE_BITS_ALL, 152 ("phys_pager_getpages: partially valid page %p", m[i])); 153 KASSERT(m[i]->dirty == 0, 154 ("phys_pager_getpages: dirty page %p", m[i])); 155 } 156 if (rbehind) 157 *rbehind = 0; 158 if (rahead) 159 *rahead = 0; 160 return (VM_PAGER_OK); 161 } 162 163 /* 164 * Implement a pretty aggressive clustered getpages strategy. Hint that 165 * everything in an entire 4MB window should be prefaulted at once. 166 * 167 * 4MB (1024 slots per page table page) is convenient for x86, 168 * but may not be for other arches. 169 */ 170 #ifndef PHYSCLUSTER 171 #define PHYSCLUSTER 1024 172 #endif 173 static int phys_pager_cluster = PHYSCLUSTER; 174 SYSCTL_INT(_vm, OID_AUTO, phys_pager_cluster, CTLFLAG_RWTUN, 175 &phys_pager_cluster, 0, 176 "prefault window size for phys pager"); 177 178 /* 179 * Max hint to vm_page_alloc() about the further allocation needs 180 * inside the phys_pager_populate() loop. The number of bits used to 181 * implement VM_ALLOC_COUNT() determines the hard limit on this value. 182 * That limit is currently 65535. 183 */ 184 #define PHYSALLOC 16 185 186 static int 187 phys_pager_populate(vm_object_t object, vm_pindex_t pidx, 188 int fault_type __unused, vm_prot_t max_prot __unused, vm_pindex_t *first, 189 vm_pindex_t *last) 190 { 191 vm_page_t m; 192 vm_pindex_t base, end, i; 193 int ahead; 194 195 base = rounddown(pidx, phys_pager_cluster); 196 end = base + phys_pager_cluster - 1; 197 if (end >= object->size) 198 end = object->size - 1; 199 if (*first > base) 200 base = *first; 201 if (end > *last) 202 end = *last; 203 *first = base; 204 *last = end; 205 206 for (i = base; i <= end; i++) { 207 retry: 208 m = vm_page_lookup(object, i); 209 if (m == NULL) { 210 ahead = MIN(end - i, PHYSALLOC); 211 m = vm_page_alloc(object, i, VM_ALLOC_NORMAL | 212 VM_ALLOC_ZERO | VM_ALLOC_WAITFAIL | 213 VM_ALLOC_COUNT(ahead)); 214 if (m == NULL) 215 goto retry; 216 if ((m->flags & PG_ZERO) == 0) 217 pmap_zero_page(m); 218 m->valid = VM_PAGE_BITS_ALL; 219 } else if (vm_page_xbusied(m)) { 220 vm_page_lock(m); 221 VM_OBJECT_WUNLOCK(object); 222 vm_page_busy_sleep(m, "physb", true); 223 VM_OBJECT_WLOCK(object); 224 goto retry; 225 } else { 226 vm_page_xbusy(m); 227 if (m->valid != VM_PAGE_BITS_ALL) 228 vm_page_zero_invalid(m, TRUE); 229 } 230 231 KASSERT(m->valid == VM_PAGE_BITS_ALL, 232 ("phys_pager_populate: partially valid page %p", m)); 233 KASSERT(m->dirty == 0, 234 ("phys_pager_populate: dirty page %p", m)); 235 } 236 return (VM_PAGER_OK); 237 } 238 239 static void 240 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, 241 int *rtvals) 242 { 243 244 panic("phys_pager_putpage called"); 245 } 246 247 static boolean_t 248 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 249 int *after) 250 { 251 vm_pindex_t base, end; 252 253 base = rounddown(pindex, phys_pager_cluster); 254 end = base + phys_pager_cluster - 1; 255 if (before != NULL) 256 *before = pindex - base; 257 if (after != NULL) 258 *after = end - pindex; 259 return (TRUE); 260 } 261 262 struct pagerops physpagerops = { 263 .pgo_init = phys_pager_init, 264 .pgo_alloc = phys_pager_alloc, 265 .pgo_dealloc = phys_pager_dealloc, 266 .pgo_getpages = phys_pager_getpages, 267 .pgo_putpages = phys_pager_putpages, 268 .pgo_haspage = phys_pager_haspage, 269 .pgo_populate = phys_pager_populate, 270 }; 271