FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_kern.c
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 1.27.2.4 1999/09/05 08:24:26 peter Exp $
65 */
66
67 /*
68 * Kernel memory management.
69 */
70
71 #include <sys/param.h>
72 #include <sys/systm.h>
73 #include <sys/kernel.h>
74 #include <sys/proc.h>
75 #include <sys/malloc.h>
76 #include <sys/syslog.h>
77 #include <sys/queue.h>
78 #include <sys/vmmeter.h>
79
80 #include <vm/vm.h>
81 #include <vm/vm_param.h>
82 #include <vm/vm_prot.h>
83 #include <vm/lock.h>
84 #include <vm/pmap.h>
85 #include <vm/vm_map.h>
86 #include <vm/vm_object.h>
87 #include <vm/vm_page.h>
88 #include <vm/vm_pageout.h>
89 #include <vm/vm_kern.h>
90 #include <vm/vm_extern.h>
91
92 vm_map_t kernel_map=0;
93 vm_map_t kmem_map=0;
94 vm_map_t exec_map=0;
95 vm_map_t clean_map=0;
96 vm_map_t u_map=0;
97 vm_map_t buffer_map=0;
98 vm_map_t mb_map=0;
99 int mb_map_full=0;
100 vm_map_t io_map=0;
101 vm_map_t phys_map=0;
102
103 /*
104 * kmem_alloc_pageable:
105 *
106 * Allocate pageable memory to the kernel's address map.
107 * "map" must be kernel_map or a submap of kernel_map.
108 */
109
110 vm_offset_t
111 kmem_alloc_pageable(map, size)
112 vm_map_t map;
113 register vm_size_t size;
114 {
115 vm_offset_t addr;
116 register int result;
117
118 size = round_page(size);
119 addr = vm_map_min(map);
120 result = vm_map_find(map, NULL, (vm_offset_t) 0,
121 &addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
122 if (result != KERN_SUCCESS) {
123 return (0);
124 }
125 return (addr);
126 }
127
128 /*
129 * Allocate wired-down memory in the kernel's address map
130 * or a submap.
131 */
132 vm_offset_t
133 kmem_alloc(map, size)
134 register vm_map_t map;
135 register vm_size_t size;
136 {
137 vm_offset_t addr;
138 register vm_offset_t offset;
139 vm_offset_t i;
140
141 size = round_page(size);
142
143 /*
144 * Use the kernel object for wired-down kernel pages. Assume that no
145 * region of the kernel object is referenced more than once.
146 */
147
148 /*
149 * Locate sufficient space in the map. This will give us the final
150 * virtual address for the new memory, and thus will tell us the
151 * offset within the kernel map.
152 */
153 vm_map_lock(map);
154 if (vm_map_findspace(map, 0, size, &addr)) {
155 vm_map_unlock(map);
156 return (0);
157 }
158 offset = addr - VM_MIN_KERNEL_ADDRESS;
159 vm_object_reference(kernel_object);
160 vm_map_insert(map, kernel_object, offset, addr, addr + size,
161 VM_PROT_ALL, VM_PROT_ALL, 0);
162 vm_map_unlock(map);
163
164 /*
165 * Guarantee that there are pages already in this object before
166 * calling vm_map_pageable. This is to prevent the following
167 * scenario:
168 *
169 * 1) Threads have swapped out, so that there is a pager for the
170 * kernel_object. 2) The kmsg zone is empty, and so we are
171 * kmem_allocing a new page for it. 3) vm_map_pageable calls vm_fault;
172 * there is no page, but there is a pager, so we call
173 * pager_data_request. But the kmsg zone is empty, so we must
174 * kmem_alloc. 4) goto 1 5) Even if the kmsg zone is not empty: when
175 * we get the data back from the pager, it will be (very stale)
176 * non-zero data. kmem_alloc is defined to return zero-filled memory.
177 *
178 * We're intentionally not activating the pages we allocate to prevent a
179 * race with page-out. vm_map_pageable will wire the pages.
180 */
181
182 for (i = 0; i < size; i += PAGE_SIZE) {
183 vm_page_t mem;
184
185 while ((mem = vm_page_alloc(kernel_object,
186 OFF_TO_IDX(offset + i), VM_ALLOC_ZERO)) == NULL) {
187 VM_WAIT;
188 }
189 if ((mem->flags & PG_ZERO) == 0)
190 vm_page_zero_fill(mem);
191 mem->flags &= ~(PG_BUSY|PG_ZERO);
192 mem->valid = VM_PAGE_BITS_ALL;
193 }
194
195 /*
196 * And finally, mark the data as non-pageable.
197 */
198
199 (void) vm_map_pageable(map, (vm_offset_t) addr, addr + size, FALSE);
200
201 return (addr);
202 }
203
204 /*
205 * kmem_free:
206 *
207 * Release a region of kernel virtual memory allocated
208 * with kmem_alloc, and return the physical pages
209 * associated with that region.
210 */
211 void
212 kmem_free(map, addr, size)
213 vm_map_t map;
214 register vm_offset_t addr;
215 vm_size_t size;
216 {
217 (void) vm_map_remove(map, trunc_page(addr), round_page(addr + size));
218 }
219
220 /*
221 * kmem_suballoc:
222 *
223 * Allocates a map to manage a subrange
224 * of the kernel virtual address space.
225 *
226 * Arguments are as follows:
227 *
228 * parent Map to take range from
229 * size Size of range to find
230 * min, max Returned endpoints of map
231 * pageable Can the region be paged
232 */
233 vm_map_t
234 kmem_suballoc(parent, min, max, size, pageable)
235 register vm_map_t parent;
236 vm_offset_t *min, *max;
237 register vm_size_t size;
238 boolean_t pageable;
239 {
240 register int ret;
241 vm_map_t result;
242
243 size = round_page(size);
244
245 *min = (vm_offset_t) vm_map_min(parent);
246 ret = vm_map_find(parent, NULL, (vm_offset_t) 0,
247 min, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
248 if (ret != KERN_SUCCESS) {
249 printf("kmem_suballoc: bad status return of %d.\n", ret);
250 panic("kmem_suballoc");
251 }
252 *max = *min + size;
253 pmap_reference(vm_map_pmap(parent));
254 result = vm_map_create(vm_map_pmap(parent), *min, *max, pageable);
255 if (result == NULL)
256 panic("kmem_suballoc: cannot create submap");
257 if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS)
258 panic("kmem_suballoc: unable to change range to submap");
259 return (result);
260 }
261
262 /*
263 * Allocate wired-down memory in the kernel's address map for the higher
264 * level kernel memory allocator (kern/kern_malloc.c). We cannot use
265 * kmem_alloc() because we may need to allocate memory at interrupt
266 * level where we cannot block (canwait == FALSE).
267 *
268 * This routine has its own private kernel submap (kmem_map) and object
269 * (kmem_object). This, combined with the fact that only malloc uses
270 * this routine, ensures that we will never block in map or object waits.
271 *
272 * Note that this still only works in a uni-processor environment and
273 * when called at splhigh().
274 *
275 * We don't worry about expanding the map (adding entries) since entries
276 * for wired maps are statically allocated.
277 */
278 vm_offset_t
279 kmem_malloc(map, size, waitflag)
280 register vm_map_t map;
281 register vm_size_t size;
282 boolean_t waitflag;
283 {
284 register vm_offset_t offset, i;
285 vm_map_entry_t entry;
286 vm_offset_t addr;
287 vm_page_t m;
288
289 if (map != kmem_map && map != mb_map)
290 panic("kmem_malloc: map != {kmem,mb}_map");
291
292 size = round_page(size);
293 addr = vm_map_min(map);
294
295 /*
296 * Locate sufficient space in the map. This will give us the final
297 * virtual address for the new memory, and thus will tell us the
298 * offset within the kernel map.
299 */
300 vm_map_lock(map);
301 if (vm_map_findspace(map, 0, size, &addr)) {
302 vm_map_unlock(map);
303 if (map == mb_map) {
304 mb_map_full = TRUE;
305 log(LOG_ERR, "Out of mbuf clusters - increase maxusers!\n");
306 return (0);
307 }
308 if (waitflag == M_WAITOK)
309 panic("kmem_malloc: kmem_map too small");
310 return (0);
311 }
312 offset = addr - VM_MIN_KERNEL_ADDRESS;
313 vm_object_reference(kmem_object);
314 vm_map_insert(map, kmem_object, offset, addr, addr + size,
315 VM_PROT_ALL, VM_PROT_ALL, 0);
316
317 for (i = 0; i < size; i += PAGE_SIZE) {
318 retry:
319 m = vm_page_alloc(kmem_object, OFF_TO_IDX(offset + i),
320 (waitflag == M_NOWAIT) ? VM_ALLOC_INTERRUPT : VM_ALLOC_SYSTEM);
321
322 /*
323 * Ran out of space, free everything up and return. Don't need
324 * to lock page queues here as we know that the pages we got
325 * aren't on any queues.
326 */
327 if (m == NULL) {
328 if (waitflag == M_WAITOK) {
329 VM_WAIT;
330 goto retry;
331 }
332 while (i != 0) {
333 i -= PAGE_SIZE;
334 m = vm_page_lookup(kmem_object,
335 OFF_TO_IDX(offset + i));
336 PAGE_WAKEUP(m);
337 vm_page_free(m);
338 }
339 vm_map_delete(map, addr, addr + size);
340 vm_map_unlock(map);
341 return (0);
342 }
343 m->flags &= ~PG_ZERO;
344 m->valid = VM_PAGE_BITS_ALL;
345 }
346
347 /*
348 * Mark map entry as non-pageable. Assert: vm_map_insert() will never
349 * be able to extend the previous entry so there will be a new entry
350 * exactly corresponding to this address range and it will have
351 * wired_count == 0.
352 */
353 if (!vm_map_lookup_entry(map, addr, &entry) ||
354 entry->start != addr || entry->end != addr + size ||
355 entry->wired_count)
356 panic("kmem_malloc: entry not found or misaligned");
357 entry->wired_count++;
358
359 vm_map_simplify_entry(map, entry);
360
361 /*
362 * Loop thru pages, entering them in the pmap. (We cannot add them to
363 * the wired count without wrapping the vm_page_queue_lock in
364 * splimp...)
365 */
366 for (i = 0; i < size; i += PAGE_SIZE) {
367 m = vm_page_lookup(kmem_object, OFF_TO_IDX(offset + i));
368 vm_page_wire(m);
369 PAGE_WAKEUP(m);
370 pmap_enter(kernel_pmap, addr + i, VM_PAGE_TO_PHYS(m),
371 VM_PROT_ALL, 1);
372 m->flags |= PG_MAPPED|PG_WRITEABLE;
373 }
374 vm_map_unlock(map);
375
376 return (addr);
377 }
378
379 /*
380 * kmem_alloc_wait
381 *
382 * Allocates pageable memory from a sub-map of the kernel. If the submap
383 * has no room, the caller sleeps waiting for more memory in the submap.
384 *
385 */
386 vm_offset_t
387 kmem_alloc_wait(map, size)
388 vm_map_t map;
389 vm_size_t size;
390 {
391 vm_offset_t addr;
392
393 size = round_page(size);
394
395 for (;;) {
396 /*
397 * To make this work for more than one map, use the map's lock
398 * to lock out sleepers/wakers.
399 */
400 vm_map_lock(map);
401 if (vm_map_findspace(map, 0, size, &addr) == 0)
402 break;
403 /* no space now; see if we can ever get space */
404 if (vm_map_max(map) - vm_map_min(map) < size) {
405 vm_map_unlock(map);
406 return (0);
407 }
408 vm_map_unlock(map);
409 tsleep(map, PVM, "kmaw", 0);
410 }
411 vm_map_insert(map, NULL, (vm_offset_t) 0, addr, addr + size, VM_PROT_ALL, VM_PROT_ALL, 0);
412 vm_map_unlock(map);
413 return (addr);
414 }
415
416 /*
417 * kmem_free_wakeup
418 *
419 * Returns memory to a submap of the kernel, and wakes up any processes
420 * waiting for memory in that map.
421 */
422 void
423 kmem_free_wakeup(map, addr, size)
424 vm_map_t map;
425 vm_offset_t addr;
426 vm_size_t size;
427 {
428 vm_map_lock(map);
429 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size));
430 wakeup(map);
431 vm_map_unlock(map);
432 }
433
434 /*
435 * Create the kernel map; insert a mapping covering kernel text, data, bss,
436 * and all space allocated thus far (`boostrap' data). The new map will thus
437 * map the range between VM_MIN_KERNEL_ADDRESS and `start' as allocated, and
438 * the range between `start' and `end' as free.
439 */
440 void
441 kmem_init(start, end)
442 vm_offset_t start, end;
443 {
444 register vm_map_t m;
445
446 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end, FALSE);
447 vm_map_lock(m);
448 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */
449 kernel_map = m;
450 (void) vm_map_insert(m, NULL, (vm_offset_t) 0,
451 VM_MIN_KERNEL_ADDRESS, start, VM_PROT_ALL, VM_PROT_ALL, 0);
452 /* ... and ending with the completion of the above `insert' */
453 vm_map_unlock(m);
454 }
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