2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
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18 * This product includes software developed by the University of
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24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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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
36 * from: @(#)vm_kern.c 8.3 (Berkeley) 1/12/94
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
42 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
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.
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.
54 * Carnegie Mellon requests users of this software to return to
56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
57 * School of Computer Science
58 * Carnegie Mellon University
59 * Pittsburgh PA 15213-3890
61 * any improvements or extensions that they make and grant Carnegie the
62 * rights to redistribute these changes.
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 1.11 2003/10/19 00:23:30 dillon Exp $
69 * Kernel memory management.
72 #include <sys/param.h>
73 #include <sys/systm.h>
75 #include <sys/malloc.h>
78 #include <vm/vm_param.h>
81 #include <vm/vm_map.h>
82 #include <vm/vm_object.h>
83 #include <vm/vm_page.h>
84 #include <vm/vm_pageout.h>
85 #include <vm/vm_extern.h>
87 vm_map_t kernel_map=0;
90 vm_map_t buffer_map=0;
95 * kmem_alloc_pageable:
97 * Allocate pageable memory to the kernel's address map.
98 * "map" must be kernel_map or a submap of kernel_map.
102 kmem_alloc_pageable(map, size)
109 size = round_page(size);
110 addr = vm_map_min(map);
111 result = vm_map_find(map, NULL, (vm_offset_t) 0,
112 &addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
113 if (result != KERN_SUCCESS) {
120 * kmem_alloc_nofault:
122 * Same as kmem_alloc_pageable, except that it create a nofault entry.
126 kmem_alloc_nofault(map, size)
133 size = round_page(size);
134 addr = vm_map_min(map);
135 result = vm_map_find(map, NULL, (vm_offset_t) 0,
136 &addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
137 if (result != KERN_SUCCESS) {
144 * Allocate wired-down memory in the kernel's address map
148 kmem_alloc(vm_map_t map, vm_size_t size)
155 size = round_page(size);
157 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT);
160 * Use the kernel object for wired-down kernel pages. Assume that no
161 * region of the kernel object is referenced more than once.
163 * Locate sufficient space in the map. This will give us the final
164 * virtual address for the new memory, and thus will tell us the
165 * offset within the kernel map.
168 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr)) {
170 vm_map_entry_krelease(count);
173 offset = addr - VM_MIN_KERNEL_ADDRESS;
174 vm_object_reference(kernel_object);
175 vm_map_insert(map, &count,
176 kernel_object, offset, addr, addr + size,
177 VM_PROT_ALL, VM_PROT_ALL, 0);
179 vm_map_entry_krelease(count);
182 * Guarantee that there are pages already in this object before
183 * calling vm_map_wire. This is to prevent the following
186 * 1) Threads have swapped out, so that there is a pager for the
187 * kernel_object. 2) The kmsg zone is empty, and so we are
188 * kmem_allocing a new page for it. 3) vm_map_wire calls vm_fault;
189 * there is no page, but there is a pager, so we call
190 * pager_data_request. But the kmsg zone is empty, so we must
191 * kmem_alloc. 4) goto 1 5) Even if the kmsg zone is not empty: when
192 * we get the data back from the pager, it will be (very stale)
193 * non-zero data. kmem_alloc is defined to return zero-filled memory.
195 * We're intentionally not activating the pages we allocate to prevent a
196 * race with page-out. vm_map_wire will wire the pages.
199 for (i = 0; i < size; i += PAGE_SIZE) {
202 mem = vm_page_grab(kernel_object, OFF_TO_IDX(offset + i),
203 VM_ALLOC_ZERO | VM_ALLOC_RETRY);
204 if ((mem->flags & PG_ZERO) == 0)
205 vm_page_zero_fill(mem);
206 mem->valid = VM_PAGE_BITS_ALL;
207 vm_page_flag_clear(mem, PG_ZERO);
212 * And finally, mark the data as non-pageable.
215 (void) vm_map_wire(map, (vm_offset_t) addr, addr + size, FALSE);
223 * Release a region of kernel virtual memory allocated
224 * with kmem_alloc, and return the physical pages
225 * associated with that region.
227 * This routine may not block on kernel maps.
230 kmem_free(map, addr, size)
235 (void) vm_map_remove(map, trunc_page(addr), round_page(addr + size));
241 * Allocates a map to manage a subrange
242 * of the kernel virtual address space.
244 * Arguments are as follows:
246 * parent Map to take range from
247 * size Size of range to find
248 * min, max Returned endpoints of map
249 * pageable Can the region be paged
252 kmem_suballoc(parent, min, max, size)
254 vm_offset_t *min, *max;
260 size = round_page(size);
262 *min = (vm_offset_t) vm_map_min(parent);
263 ret = vm_map_find(parent, NULL, (vm_offset_t) 0,
264 min, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
265 if (ret != KERN_SUCCESS) {
266 printf("kmem_suballoc: bad status return of %d.\n", ret);
267 panic("kmem_suballoc");
270 pmap_reference(vm_map_pmap(parent));
271 result = vm_map_create(vm_map_pmap(parent), *min, *max);
273 panic("kmem_suballoc: cannot create submap");
274 if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS)
275 panic("kmem_suballoc: unable to change range to submap");
282 * Allocate wired-down memory in the kernel's address map for the higher
283 * level kernel memory allocator (kern/kern_malloc.c). We cannot use
284 * kmem_alloc() because we may need to allocate memory at interrupt
285 * level where we cannot block (canwait == FALSE).
287 * This routine has its own private kernel submap (kmem_map) and object
288 * (kmem_object). This, combined with the fact that only malloc uses
289 * this routine, ensures that we will never block in map or object waits.
291 * Note that this still only works in a uni-processor environment and
292 * when called at splhigh().
294 * We don't worry about expanding the map (adding entries) since entries
295 * for wired maps are statically allocated.
297 * NOTE: This routine is not supposed to block if M_NOWAIT is set, but
298 * I have not verified that it actually does not block.
301 kmem_malloc(vm_map_t map, vm_size_t size, int flags)
303 vm_offset_t offset, i;
304 vm_map_entry_t entry;
309 if (map != kernel_map && map != mb_map)
310 panic("kmem_malloc: map != {kmem,mb}_map");
312 size = round_page(size);
313 addr = vm_map_min(map);
316 * Locate sufficient space in the map. This will give us the final
317 * virtual address for the new memory, and thus will tell us the
318 * offset within the kernel map.
321 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT);
322 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr)) {
324 vm_map_entry_krelease(count);
327 printf("Out of mbuf clusters - adjust NMBCLUSTERS or increase maxusers!\n");
330 if ((flags & M_NOWAIT) == 0)
331 panic("kmem_malloc(%ld): kernel_map too small: %ld total allocated",
332 (long)size, (long)map->size);
335 offset = addr - VM_MIN_KERNEL_ADDRESS;
336 vm_object_reference(kmem_object);
337 vm_map_insert(map, &count,
338 kmem_object, offset, addr, addr + size,
339 VM_PROT_ALL, VM_PROT_ALL, 0);
341 for (i = 0; i < size; i += PAGE_SIZE) {
343 * Note: if M_NOWAIT specified alone, allocate from
344 * interrupt-safe queues only (just the free list). If
345 * M_USE_RESERVE is also specified, we can also
346 * allocate from the cache. Neither of the latter two
347 * flags may be specified from an interrupt since interrupts
348 * are not allowed to mess with the cache queue.
351 m = vm_page_alloc(kmem_object, OFF_TO_IDX(offset + i),
352 ((flags & (M_NOWAIT|M_USE_RESERVE)) == M_NOWAIT) ?
357 * Ran out of space, free everything up and return. Don't need
358 * to lock page queues here as we know that the pages we got
359 * aren't on any queues.
362 if ((flags & M_NOWAIT) == 0) {
369 * Free the pages before removing the map entry.
370 * They are already marked busy. Calling
371 * vm_map_delete before the pages has been freed or
372 * unbusied will cause a deadlock.
376 m = vm_page_lookup(kmem_object,
377 OFF_TO_IDX(offset + i));
380 vm_map_delete(map, addr, addr + size, &count);
382 vm_map_entry_krelease(count);
385 vm_page_flag_clear(m, PG_ZERO);
386 m->valid = VM_PAGE_BITS_ALL;
390 * Mark map entry as non-pageable. Assert: vm_map_insert() will never
391 * be able to extend the previous entry so there will be a new entry
392 * exactly corresponding to this address range and it will have
395 if (!vm_map_lookup_entry(map, addr, &entry) ||
396 entry->start != addr || entry->end != addr + size ||
397 entry->wired_count != 0)
398 panic("kmem_malloc: entry not found or misaligned");
399 entry->wired_count = 1;
401 vm_map_simplify_entry(map, entry, &count);
404 * Loop thru pages, entering them in the pmap. (We cannot add them to
405 * the wired count without wrapping the vm_page_queue_lock in
408 for (i = 0; i < size; i += PAGE_SIZE) {
409 m = vm_page_lookup(kmem_object, OFF_TO_IDX(offset + i));
413 * Because this is kernel_pmap, this call will not block.
415 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 1);
416 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED);
419 vm_map_entry_krelease(count);
427 * Allocates pageable memory from a sub-map of the kernel. If the submap
428 * has no room, the caller sleeps waiting for more memory in the submap.
430 * This routine may block.
434 kmem_alloc_wait(vm_map_t map, vm_size_t size)
439 size = round_page(size);
441 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT);
445 * To make this work for more than one map, use the map's lock
446 * to lock out sleepers/wakers.
449 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr) == 0)
451 /* no space now; see if we can ever get space */
452 if (vm_map_max(map) - vm_map_min(map) < size) {
453 vm_map_entry_krelease(count);
458 tsleep(map, 0, "kmaw", 0);
460 vm_map_insert(map, &count,
461 NULL, (vm_offset_t) 0,
462 addr, addr + size, VM_PROT_ALL, VM_PROT_ALL, 0);
464 vm_map_entry_krelease(count);
471 * Returns memory to a submap of the kernel, and wakes up any processes
472 * waiting for memory in that map.
475 kmem_free_wakeup(map, addr, size)
482 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT);
484 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size), &count);
487 vm_map_entry_krelease(count);
493 * Create the kernel map; insert a mapping covering kernel text,
494 * data, bss, and all space allocated thus far (`boostrap' data). The
495 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and
496 * `start' as allocated, and the range between `start' and `end' as free.
498 * Depend on the zalloc bootstrap cache to get our vm_map_entry_t.
501 kmem_init(vm_offset_t start, vm_offset_t end)
506 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
508 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */
510 kernel_map->system_map = 1;
511 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
512 (void) vm_map_insert(m, &count, NULL, (vm_offset_t) 0,
513 VM_MIN_KERNEL_ADDRESS, start, VM_PROT_ALL, VM_PROT_ALL, 0);
514 /* ... and ending with the completion of the above `insert' */
516 vm_map_entry_release(count);
522 * Load up extra vm_map_entry structures in each cpu's globaldata
523 * cache. These allow us to expand the mapent zone for kernel_map.
524 * Without them we would get into a recursion deadlock trying to
525 * reserve map entries (reserve->zalloc->kmem_alloc->reserve->...)
530 vm_map_entry_reserve(MAP_RESERVE_COUNT * 2);