1 /* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)vm_kern.c 8.3 (Berkeley) 1/12/94 37 * 38 * 39 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 40 * All rights reserved. 41 * 42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 43 * 44 * Permission to use, copy, modify and distribute this software and 45 * its documentation is hereby granted, provided that both the copyright 46 * notice and this permission notice appear in all copies of the 47 * software, derivative works or modified versions, and any portions 48 * thereof, and that both notices appear in supporting documentation. 49 * 50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 53 * 54 * Carnegie Mellon requests users of this software to return to 55 * 56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 57 * School of Computer Science 58 * Carnegie Mellon University 59 * Pittsburgh PA 15213-3890 60 * 61 * any improvements or extensions that they make and grant Carnegie the 62 * rights to redistribute these changes. 63 * 64 * $FreeBSD: src/sys/vm/vm_kern.c,v 1.61.2.2 2002/03/12 18:25:26 tegge Exp $ 65 * $DragonFly: src/sys/vm/vm_kern.c,v 1.29 2007/06/07 23:14:29 dillon Exp $ 66 */ 67 68 /* 69 * Kernel memory management. 70 */ 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/proc.h> 75 #include <sys/malloc.h> 76 #include <sys/kernel.h> 77 #include <sys/sysctl.h> 78 79 #include <vm/vm.h> 80 #include <vm/vm_param.h> 81 #include <sys/lock.h> 82 #include <vm/pmap.h> 83 #include <vm/vm_map.h> 84 #include <vm/vm_object.h> 85 #include <vm/vm_page.h> 86 #include <vm/vm_pageout.h> 87 #include <vm/vm_kern.h> 88 #include <vm/vm_extern.h> 89 90 struct vm_map kernel_map; 91 struct vm_map clean_map; 92 struct vm_map buffer_map; 93 94 /* 95 * kmem_alloc_pageable: 96 * 97 * Allocate pageable memory to the kernel's address map. 98 * "map" must be kernel_map or a submap of kernel_map. 99 */ 100 vm_offset_t 101 kmem_alloc_pageable(vm_map_t map, vm_size_t size) 102 { 103 vm_offset_t addr; 104 int result; 105 106 size = round_page(size); 107 addr = vm_map_min(map); 108 result = vm_map_find(map, NULL, (vm_offset_t) 0, 109 &addr, size, 110 TRUE, 111 VM_MAPTYPE_NORMAL, 112 VM_PROT_ALL, VM_PROT_ALL, 113 0); 114 if (result != KERN_SUCCESS) { 115 return (0); 116 } 117 return (addr); 118 } 119 120 /* 121 * kmem_alloc_nofault: 122 * 123 * Same as kmem_alloc_pageable, except that it create a nofault entry. 124 */ 125 vm_offset_t 126 kmem_alloc_nofault(vm_map_t map, vm_size_t size) 127 { 128 vm_offset_t addr; 129 int result; 130 131 size = round_page(size); 132 addr = vm_map_min(map); 133 result = vm_map_find(map, NULL, (vm_offset_t) 0, 134 &addr, size, 135 TRUE, 136 VM_MAPTYPE_NORMAL, 137 VM_PROT_ALL, VM_PROT_ALL, 138 MAP_NOFAULT); 139 if (result != KERN_SUCCESS) { 140 return (0); 141 } 142 return (addr); 143 } 144 145 /* 146 * Allocate wired-down memory in the kernel's address map 147 * or a submap. 148 */ 149 vm_offset_t 150 kmem_alloc3(vm_map_t map, vm_size_t size, int kmflags) 151 { 152 vm_offset_t addr; 153 vm_offset_t i; 154 int count; 155 156 size = round_page(size); 157 158 if (kmflags & KM_KRESERVE) 159 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT); 160 else 161 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 162 163 /* 164 * Use the kernel object for wired-down kernel pages. Assume that no 165 * region of the kernel object is referenced more than once. 166 * 167 * Locate sufficient space in the map. This will give us the final 168 * virtual address for the new memory, and thus will tell us the 169 * offset within the kernel map. 170 */ 171 vm_map_lock(map); 172 if (vm_map_findspace(map, vm_map_min(map), size, 1, 0, &addr)) { 173 vm_map_unlock(map); 174 if (kmflags & KM_KRESERVE) 175 vm_map_entry_krelease(count); 176 else 177 vm_map_entry_release(count); 178 return (0); 179 } 180 vm_object_reference(&kernel_object); 181 vm_map_insert(map, &count, 182 &kernel_object, addr, addr, addr + size, 183 VM_MAPTYPE_NORMAL, 184 VM_PROT_ALL, VM_PROT_ALL, 185 0); 186 vm_map_unlock(map); 187 if (kmflags & KM_KRESERVE) 188 vm_map_entry_krelease(count); 189 else 190 vm_map_entry_release(count); 191 192 /* 193 * Guarantee that there are pages already in this object before 194 * calling vm_map_wire. This is to prevent the following 195 * scenario: 196 * 197 * 1) Threads have swapped out, so that there is a pager for the 198 * kernel_object. 2) The kmsg zone is empty, and so we are 199 * kmem_allocing a new page for it. 3) vm_map_wire calls vm_fault; 200 * there is no page, but there is a pager, so we call 201 * pager_data_request. But the kmsg zone is empty, so we must 202 * kmem_alloc. 4) goto 1 5) Even if the kmsg zone is not empty: when 203 * we get the data back from the pager, it will be (very stale) 204 * non-zero data. kmem_alloc is defined to return zero-filled memory. 205 * 206 * We're intentionally not activating the pages we allocate to prevent a 207 * race with page-out. vm_map_wire will wire the pages. 208 */ 209 210 for (i = 0; i < size; i += PAGE_SIZE) { 211 vm_page_t mem; 212 213 mem = vm_page_grab(&kernel_object, OFF_TO_IDX(addr + i), 214 VM_ALLOC_ZERO | VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 215 if ((mem->flags & PG_ZERO) == 0) 216 vm_page_zero_fill(mem); 217 mem->valid = VM_PAGE_BITS_ALL; 218 vm_page_flag_clear(mem, PG_ZERO); 219 vm_page_wakeup(mem); 220 } 221 222 /* 223 * And finally, mark the data as non-pageable. 224 */ 225 226 vm_map_wire(map, (vm_offset_t) addr, addr + size, kmflags); 227 228 return (addr); 229 } 230 231 /* 232 * kmem_free: 233 * 234 * Release a region of kernel virtual memory allocated 235 * with kmem_alloc, and return the physical pages 236 * associated with that region. 237 * 238 * This routine may not block on kernel maps. 239 */ 240 void 241 kmem_free(vm_map_t map, vm_offset_t addr, vm_size_t size) 242 { 243 vm_map_remove(map, trunc_page(addr), round_page(addr + size)); 244 } 245 246 /* 247 * kmem_suballoc: 248 * 249 * Used to break a system map into smaller maps, usually to reduce 250 * contention and to provide large KVA spaces for subsystems like the 251 * buffer cache. 252 * 253 * parent Map to take range from 254 * result 255 * size Size of range to find 256 * min, max Returned endpoints of map 257 * pageable Can the region be paged 258 */ 259 void 260 kmem_suballoc(vm_map_t parent, vm_map_t result, 261 vm_offset_t *min, vm_offset_t *max, vm_size_t size) 262 { 263 int ret; 264 265 size = round_page(size); 266 267 *min = (vm_offset_t) vm_map_min(parent); 268 ret = vm_map_find(parent, NULL, (vm_offset_t) 0, 269 min, size, 270 TRUE, 271 VM_MAPTYPE_UNSPECIFIED, 272 VM_PROT_ALL, VM_PROT_ALL, 273 0); 274 if (ret != KERN_SUCCESS) { 275 kprintf("kmem_suballoc: bad status return of %d.\n", ret); 276 panic("kmem_suballoc"); 277 } 278 *max = *min + size; 279 pmap_reference(vm_map_pmap(parent)); 280 vm_map_init(result, *min, *max, vm_map_pmap(parent)); 281 if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS) 282 panic("kmem_suballoc: unable to change range to submap"); 283 } 284 285 /* 286 * kmem_alloc_wait: 287 * 288 * Allocates pageable memory from a sub-map of the kernel. If the submap 289 * has no room, the caller sleeps waiting for more memory in the submap. 290 * 291 * This routine may block. 292 */ 293 294 vm_offset_t 295 kmem_alloc_wait(vm_map_t map, vm_size_t size) 296 { 297 vm_offset_t addr; 298 int count; 299 300 size = round_page(size); 301 302 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 303 304 for (;;) { 305 /* 306 * To make this work for more than one map, use the map's lock 307 * to lock out sleepers/wakers. 308 */ 309 vm_map_lock(map); 310 if (vm_map_findspace(map, vm_map_min(map), size, 311 1, 0, &addr) == 0) { 312 break; 313 } 314 /* no space now; see if we can ever get space */ 315 if (vm_map_max(map) - vm_map_min(map) < size) { 316 vm_map_entry_release(count); 317 vm_map_unlock(map); 318 return (0); 319 } 320 vm_map_unlock(map); 321 tsleep(map, 0, "kmaw", 0); 322 } 323 vm_map_insert(map, &count, 324 NULL, (vm_offset_t) 0, 325 addr, addr + size, 326 VM_MAPTYPE_NORMAL, 327 VM_PROT_ALL, VM_PROT_ALL, 328 0); 329 vm_map_unlock(map); 330 vm_map_entry_release(count); 331 return (addr); 332 } 333 334 /* 335 * kmem_free_wakeup: 336 * 337 * Returns memory to a submap of the kernel, and wakes up any processes 338 * waiting for memory in that map. 339 */ 340 void 341 kmem_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size) 342 { 343 int count; 344 345 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 346 vm_map_lock(map); 347 vm_map_delete(map, trunc_page(addr), round_page(addr + size), &count); 348 wakeup(map); 349 vm_map_unlock(map); 350 vm_map_entry_release(count); 351 } 352 353 /* 354 * kmem_init: 355 * 356 * Create the kernel_map and insert mappings to cover areas already 357 * allocated or reserved thus far. That is, the area (KvaStart,start) 358 * and (end,KvaEnd) must be marked as allocated. 359 * 360 * We could use a min_offset of 0 instead of KvaStart, but since the 361 * min_offset is not used for any calculations other then a bounds check 362 * it does not effect readability. KvaStart is more appropriate. 363 * 364 * Depend on the zalloc bootstrap cache to get our vm_map_entry_t. 365 */ 366 void 367 kmem_init(vm_offset_t start, vm_offset_t end) 368 { 369 vm_map_t m; 370 int count; 371 372 m = vm_map_create(&kernel_map, &kernel_pmap, KvaStart, KvaEnd); 373 vm_map_lock(m); 374 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */ 375 m->system_map = 1; 376 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 377 if (KvaStart != start) { 378 vm_map_insert(m, &count, NULL, (vm_offset_t) 0, 379 KvaStart, start, 380 VM_MAPTYPE_NORMAL, 381 VM_PROT_ALL, VM_PROT_ALL, 382 0); 383 } 384 if (KvaEnd != end) { 385 vm_map_insert(m, &count, NULL, (vm_offset_t) 0, 386 end, KvaEnd, 387 VM_MAPTYPE_NORMAL, 388 VM_PROT_ALL, VM_PROT_ALL, 389 0); 390 } 391 /* ... and ending with the completion of the above `insert' */ 392 vm_map_unlock(m); 393 vm_map_entry_release(count); 394 } 395 396 static int 397 kvm_size(SYSCTL_HANDLER_ARGS) 398 { 399 unsigned long ksize = KvaSize; 400 401 return sysctl_handle_long(oidp, &ksize, 0, req); 402 } 403 SYSCTL_PROC(_vm, OID_AUTO, kvm_size, CTLTYPE_LONG|CTLFLAG_RD, 404 0, 0, kvm_size, "IU", "Size of KVM"); 405 406 static int 407 kvm_free(SYSCTL_HANDLER_ARGS) 408 { 409 unsigned long kfree = virtual_end - kernel_vm_end; 410 411 return sysctl_handle_long(oidp, &kfree, 0, req); 412 } 413 SYSCTL_PROC(_vm, OID_AUTO, kvm_free, CTLTYPE_LONG|CTLFLAG_RD, 414 0, 0, kvm_free, "IU", "Amount of KVM free"); 415 416