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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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 1.24 2006/12/23 00:41:31 swildner 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_kern.h>
86 #include <vm/vm_extern.h>
88 vm_map_t kernel_map=0;
91 vm_map_t buffer_map=0;
94 * kmem_alloc_pageable:
96 * Allocate pageable memory to the kernel's address map.
97 * "map" must be kernel_map or a submap of kernel_map.
100 kmem_alloc_pageable(vm_map_t map, vm_size_t size)
105 size = round_page(size);
106 addr = vm_map_min(map);
107 result = vm_map_find(map, NULL, (vm_offset_t) 0,
111 VM_PROT_ALL, VM_PROT_ALL,
113 if (result != KERN_SUCCESS) {
120 * kmem_alloc_nofault:
122 * Same as kmem_alloc_pageable, except that it create a nofault entry.
125 kmem_alloc_nofault(vm_map_t map, vm_size_t size)
130 size = round_page(size);
131 addr = vm_map_min(map);
132 result = vm_map_find(map, NULL, (vm_offset_t) 0,
136 VM_PROT_ALL, VM_PROT_ALL,
138 if (result != KERN_SUCCESS) {
145 * Allocate wired-down memory in the kernel's address map
149 kmem_alloc3(vm_map_t map, vm_size_t size, int kmflags)
156 size = round_page(size);
158 if (kmflags & KM_KRESERVE)
159 count = vm_map_entry_kreserve(MAP_RESERVE_COUNT);
161 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
164 * Use the kernel object for wired-down kernel pages. Assume that no
165 * region of the kernel object is referenced more than once.
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.
172 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr)) {
174 if (kmflags & KM_KRESERVE)
175 vm_map_entry_krelease(count);
177 vm_map_entry_release(count);
180 offset = addr - VM_MIN_KERNEL_ADDRESS;
181 vm_object_reference(kernel_object);
182 vm_map_insert(map, &count,
183 kernel_object, offset, addr, addr + size,
185 VM_PROT_ALL, VM_PROT_ALL,
188 if (kmflags & KM_KRESERVE)
189 vm_map_entry_krelease(count);
191 vm_map_entry_release(count);
194 * Guarantee that there are pages already in this object before
195 * calling vm_map_wire. This is to prevent the following
198 * 1) Threads have swapped out, so that there is a pager for the
199 * kernel_object. 2) The kmsg zone is empty, and so we are
200 * kmem_allocing a new page for it. 3) vm_map_wire calls vm_fault;
201 * there is no page, but there is a pager, so we call
202 * pager_data_request. But the kmsg zone is empty, so we must
203 * kmem_alloc. 4) goto 1 5) Even if the kmsg zone is not empty: when
204 * we get the data back from the pager, it will be (very stale)
205 * non-zero data. kmem_alloc is defined to return zero-filled memory.
207 * We're intentionally not activating the pages we allocate to prevent a
208 * race with page-out. vm_map_wire will wire the pages.
211 for (i = 0; i < size; i += PAGE_SIZE) {
214 mem = vm_page_grab(kernel_object, OFF_TO_IDX(offset + i),
215 VM_ALLOC_ZERO | VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
216 if ((mem->flags & PG_ZERO) == 0)
217 vm_page_zero_fill(mem);
218 mem->valid = VM_PAGE_BITS_ALL;
219 vm_page_flag_clear(mem, PG_ZERO);
224 * And finally, mark the data as non-pageable.
227 vm_map_wire(map, (vm_offset_t) addr, addr + size, kmflags);
235 * Release a region of kernel virtual memory allocated
236 * with kmem_alloc, and return the physical pages
237 * associated with that region.
239 * This routine may not block on kernel maps.
242 kmem_free(vm_map_t map, vm_offset_t addr, vm_size_t size)
244 vm_map_remove(map, trunc_page(addr), round_page(addr + size));
250 * Allocates a map to manage a subrange
251 * of the kernel virtual address space.
253 * Arguments are as follows:
255 * parent Map to take range from
256 * size Size of range to find
257 * min, max Returned endpoints of map
258 * pageable Can the region be paged
261 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max,
267 size = round_page(size);
269 *min = (vm_offset_t) vm_map_min(parent);
270 ret = vm_map_find(parent, NULL, (vm_offset_t) 0,
273 VM_MAPTYPE_UNSPECIFIED,
274 VM_PROT_ALL, VM_PROT_ALL,
276 if (ret != KERN_SUCCESS) {
277 kprintf("kmem_suballoc: bad status return of %d.\n", ret);
278 panic("kmem_suballoc");
281 pmap_reference(vm_map_pmap(parent));
282 result = vm_map_create(vm_map_pmap(parent), *min, *max);
284 panic("kmem_suballoc: cannot create submap");
285 if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS)
286 panic("kmem_suballoc: unable to change range to submap");
293 * Allocate wired-down memory in the kernel's address map for the higher
294 * level kernel memory allocator (kern/kern_malloc.c). We cannot use
295 * kmem_alloc() because we may need to allocate memory at interrupt
296 * level where we cannot block (canwait == FALSE).
298 * We don't worry about expanding the map (adding entries) since entries
299 * for wired maps are statically allocated.
301 * NOTE: Please see kmem_slab_alloc() for a better explanation of the
305 kmem_malloc(vm_map_t map, vm_size_t size, int flags)
307 vm_offset_t offset, i;
308 vm_map_entry_t entry;
311 int count, vmflags, wanted_reserve;
314 if (map != kernel_map)
315 panic("kmem_malloc: map != kernel_map");
317 size = round_page(size);
318 addr = vm_map_min(map);
321 * Locate sufficient space in the map. This will give us the final
322 * virtual address for the new memory, and thus will tell us the
323 * offset within the kernel map. If we are unable to allocate space
324 * and neither RNOWAIT or NULLOK is set, we panic.
326 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
328 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr)) {
330 vm_map_entry_release(count);
331 if ((flags & M_NULLOK) == 0) {
332 panic("kmem_malloc(%ld): kernel_map too small: "
333 "%ld total allocated",
334 (long)size, (long)map->size);
338 offset = addr - VM_MIN_KERNEL_ADDRESS;
339 vm_object_reference(kmem_object);
340 vm_map_insert(map, &count,
341 kmem_object, offset, addr, addr + size,
343 VM_PROT_ALL, VM_PROT_ALL,
349 vmflags = VM_ALLOC_SYSTEM; /* XXX M_USE_RESERVE? */
350 if ((flags & (M_WAITOK|M_RNOWAIT)) == 0)
351 panic("kmem_malloc: bad flags %08x (%p)\n", flags, ((int **)&map)[-1]);
352 if (flags & M_USE_INTERRUPT_RESERVE)
353 vmflags |= VM_ALLOC_INTERRUPT;
355 for (i = 0; i < size; i += PAGE_SIZE) {
357 * Only allocate PQ_CACHE pages for M_WAITOK requests and
358 * then only if we are not preempting.
360 if (flags & M_WAITOK) {
361 if (td->td_preempted) {
362 vmflags &= ~VM_ALLOC_NORMAL;
365 vmflags |= VM_ALLOC_NORMAL;
370 m = vm_page_alloc(kmem_object, OFF_TO_IDX(offset + i), vmflags);
373 * Ran out of space, free everything up and return. Don't need
374 * to lock page queues here as we know that the pages we got
375 * aren't on any queues.
377 * If M_WAITOK is set we can yield or block.
380 if (flags & M_WAITOK) {
381 if (wanted_reserve) {
390 i -= PAGE_SIZE; /* retry */
394 * Free the pages before removing the map entry.
395 * They are already marked busy. Calling
396 * vm_map_delete before the pages has been freed or
397 * unbusied will cause a deadlock.
401 m = vm_page_lookup(kmem_object,
402 OFF_TO_IDX(offset + i));
405 vm_map_delete(map, addr, addr + size, &count);
407 vm_map_entry_release(count);
410 vm_page_flag_clear(m, PG_ZERO);
411 m->valid = VM_PAGE_BITS_ALL;
415 * Mark map entry as non-pageable. Assert: vm_map_insert() will never
416 * be able to extend the previous entry so there will be a new entry
417 * exactly corresponding to this address range and it will have
420 if (!vm_map_lookup_entry(map, addr, &entry) ||
421 entry->start != addr || entry->end != addr + size ||
422 entry->wired_count != 0)
423 panic("kmem_malloc: entry not found or misaligned");
424 entry->wired_count = 1;
426 vm_map_simplify_entry(map, entry, &count);
429 * Loop thru pages, entering them in the pmap. (We cannot add them to
430 * the wired count without wrapping the vm_page_queue_lock in
433 for (i = 0; i < size; i += PAGE_SIZE) {
434 m = vm_page_lookup(kmem_object, OFF_TO_IDX(offset + i));
438 * Because this is kernel_pmap, this call will not block.
440 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 1);
441 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED);
444 vm_map_entry_release(count);
452 * Allocates pageable memory from a sub-map of the kernel. If the submap
453 * has no room, the caller sleeps waiting for more memory in the submap.
455 * This routine may block.
459 kmem_alloc_wait(vm_map_t map, vm_size_t size)
464 size = round_page(size);
466 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
470 * To make this work for more than one map, use the map's lock
471 * to lock out sleepers/wakers.
474 if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr) == 0)
476 /* no space now; see if we can ever get space */
477 if (vm_map_max(map) - vm_map_min(map) < size) {
478 vm_map_entry_release(count);
483 tsleep(map, 0, "kmaw", 0);
485 vm_map_insert(map, &count,
486 NULL, (vm_offset_t) 0,
489 VM_PROT_ALL, VM_PROT_ALL,
492 vm_map_entry_release(count);
499 * Returns memory to a submap of the kernel, and wakes up any processes
500 * waiting for memory in that map.
503 kmem_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size)
507 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
509 vm_map_delete(map, trunc_page(addr), round_page(addr + size), &count);
512 vm_map_entry_release(count);
518 * Create the kernel map; insert a mapping covering kernel text,
519 * data, bss, and all space allocated thus far (`boostrap' data). The
520 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and
521 * `start' as allocated, and the range between `start' and `end' as free.
523 * Depend on the zalloc bootstrap cache to get our vm_map_entry_t.
526 kmem_init(vm_offset_t start, vm_offset_t end)
531 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
533 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */
535 kernel_map->system_map = 1;
536 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
537 vm_map_insert(m, &count, NULL, (vm_offset_t) 0,
538 VM_MIN_KERNEL_ADDRESS, start,
540 VM_PROT_ALL, VM_PROT_ALL,
542 /* ... and ending with the completion of the above `insert' */
544 vm_map_entry_release(count);