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.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * from: @(#)vm_kern.c 8.3 (Berkeley) 1/12/94
35 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
36 * All rights reserved.
38 * Authors: Avadis Tevanian, Jr., Michael Wayne Young
40 * Permission to use, copy, modify and distribute this software and
41 * its documentation is hereby granted, provided that both the copyright
42 * notice and this permission notice appear in all copies of the
43 * software, derivative works or modified versions, and any portions
44 * thereof, and that both notices appear in supporting documentation.
46 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
47 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
48 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
50 * Carnegie Mellon requests users of this software to return to
52 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
53 * School of Computer Science
54 * Carnegie Mellon University
55 * Pittsburgh PA 15213-3890
57 * any improvements or extensions that they make and grant Carnegie the
58 * rights to redistribute these changes.
62 * Kernel memory management.
65 #include <sys/cdefs.h>
66 __FBSDID("$FreeBSD$");
68 #include <sys/param.h>
69 #include <sys/systm.h>
70 #include <sys/kernel.h> /* for ticks and hz */
71 #include <sys/eventhandler.h>
74 #include <sys/malloc.h>
75 #include <sys/rwlock.h>
76 #include <sys/sysctl.h>
80 #include <vm/vm_param.h>
81 #include <vm/vm_kern.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_extern.h>
94 const void *zero_region;
95 CTASSERT((ZERO_REGION_SIZE & PAGE_MASK) == 0);
97 /* NB: Used by kernel debuggers. */
98 const u_long vm_maxuser_address = VM_MAXUSER_ADDRESS;
100 SYSCTL_ULONG(_vm, OID_AUTO, min_kernel_address, CTLFLAG_RD,
101 SYSCTL_NULL_ULONG_PTR, VM_MIN_KERNEL_ADDRESS, "Min kernel address");
103 SYSCTL_ULONG(_vm, OID_AUTO, max_kernel_address, CTLFLAG_RD,
104 #if defined(__arm__) || defined(__sparc64__)
105 &vm_max_kernel_address, 0,
107 SYSCTL_NULL_ULONG_PTR, VM_MAX_KERNEL_ADDRESS,
109 "Max kernel address");
114 * Allocate a virtual address range with no underlying object and
115 * no initial mapping to physical memory. Any mapping from this
116 * range to physical memory must be explicitly created prior to
117 * its use, typically with pmap_qenter(). Any attempt to create
118 * a mapping on demand through vm_fault() will result in a panic.
126 size = round_page(size);
127 if (vmem_alloc(kernel_arena, size, M_BESTFIT | M_NOWAIT, &addr))
136 * Release a region of kernel virtual memory allocated
137 * with kva_alloc, and return the physical pages
138 * associated with that region.
140 * This routine may not block on kernel maps.
148 size = round_page(size);
149 vmem_free(kernel_arena, addr, size);
153 * Allocates a region from the kernel address map and physical pages
154 * within the specified address range to the kernel object. Creates a
155 * wired mapping from this region to these pages, and returns the
156 * region's starting virtual address. The allocated pages are not
157 * necessarily physically contiguous. If M_ZERO is specified through the
158 * given flags, then the pages are zeroed before they are mapped.
161 kmem_alloc_attr(vmem_t *vmem, vm_size_t size, int flags, vm_paddr_t low,
162 vm_paddr_t high, vm_memattr_t memattr)
164 vm_object_t object = vmem == kmem_arena ? kmem_object : kernel_object;
170 size = round_page(size);
171 if (vmem_alloc(vmem, size, M_BESTFIT | flags, &addr))
173 offset = addr - VM_MIN_KERNEL_ADDRESS;
174 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED;
175 VM_OBJECT_WLOCK(object);
176 for (i = 0; i < size; i += PAGE_SIZE) {
179 m = vm_page_alloc_contig(object, OFF_TO_IDX(offset + i),
180 pflags, 1, low, high, PAGE_SIZE, 0, memattr);
182 VM_OBJECT_WUNLOCK(object);
183 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) {
184 vm_pageout_grow_cache(tries, low, high);
185 VM_OBJECT_WLOCK(object);
189 kmem_unback(object, addr, i);
190 vmem_free(vmem, addr, size);
193 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0)
195 m->valid = VM_PAGE_BITS_ALL;
196 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL,
197 VM_PROT_ALL | PMAP_ENTER_WIRED, 0);
199 VM_OBJECT_WUNLOCK(object);
204 * Allocates a region from the kernel address map and physically
205 * contiguous pages within the specified address range to the kernel
206 * object. Creates a wired mapping from this region to these pages, and
207 * returns the region's starting virtual address. If M_ZERO is specified
208 * through the given flags, then the pages are zeroed before they are
212 kmem_alloc_contig(struct vmem *vmem, vm_size_t size, int flags, vm_paddr_t low,
213 vm_paddr_t high, u_long alignment, vm_paddr_t boundary,
214 vm_memattr_t memattr)
216 vm_object_t object = vmem == kmem_arena ? kmem_object : kernel_object;
217 vm_offset_t addr, tmp;
222 size = round_page(size);
223 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr))
225 offset = addr - VM_MIN_KERNEL_ADDRESS;
226 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED;
227 VM_OBJECT_WLOCK(object);
230 m = vm_page_alloc_contig(object, OFF_TO_IDX(offset), pflags,
231 atop(size), low, high, alignment, boundary, memattr);
233 VM_OBJECT_WUNLOCK(object);
234 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) {
235 vm_pageout_grow_cache(tries, low, high);
236 VM_OBJECT_WLOCK(object);
240 vmem_free(vmem, addr, size);
243 end_m = m + atop(size);
245 for (; m < end_m; m++) {
246 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0)
248 m->valid = VM_PAGE_BITS_ALL;
249 pmap_enter(kernel_pmap, tmp, m, VM_PROT_ALL,
250 VM_PROT_ALL | PMAP_ENTER_WIRED, 0);
253 VM_OBJECT_WUNLOCK(object);
260 * Allocates a map to manage a subrange
261 * of the kernel virtual address space.
263 * Arguments are as follows:
265 * parent Map to take range from
266 * min, max Returned endpoints of map
267 * size Size of range to find
268 * superpage_align Request that min is superpage aligned
271 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max,
272 vm_size_t size, boolean_t superpage_align)
277 size = round_page(size);
279 *min = vm_map_min(parent);
280 ret = vm_map_find(parent, NULL, 0, min, size, 0, superpage_align ?
281 VMFS_SUPER_SPACE : VMFS_ANY_SPACE, VM_PROT_ALL, VM_PROT_ALL,
283 if (ret != KERN_SUCCESS)
284 panic("kmem_suballoc: bad status return of %d", ret);
286 result = vm_map_create(vm_map_pmap(parent), *min, *max);
288 panic("kmem_suballoc: cannot create submap");
289 if (vm_map_submap(parent, *min, *max, result) != KERN_SUCCESS)
290 panic("kmem_suballoc: unable to change range to submap");
297 * Allocate wired-down pages in the kernel's address space.
300 kmem_malloc(struct vmem *vmem, vm_size_t size, int flags)
305 size = round_page(size);
306 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr))
309 rv = kmem_back((vmem == kmem_arena) ? kmem_object : kernel_object,
311 if (rv != KERN_SUCCESS) {
312 vmem_free(vmem, addr, size);
321 * Allocate physical pages for the specified virtual address range.
324 kmem_back(vm_object_t object, vm_offset_t addr, vm_size_t size, int flags)
326 vm_offset_t offset, i;
330 KASSERT(object == kmem_object || object == kernel_object,
331 ("kmem_back: only supports kernel objects."));
333 offset = addr - VM_MIN_KERNEL_ADDRESS;
334 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED;
336 VM_OBJECT_WLOCK(object);
337 for (i = 0; i < size; i += PAGE_SIZE) {
339 m = vm_page_alloc(object, OFF_TO_IDX(offset + i), pflags);
342 * Ran out of space, free everything up and return. Don't need
343 * to lock page queues here as we know that the pages we got
344 * aren't on any queues.
347 VM_OBJECT_WUNLOCK(object);
348 if ((flags & M_NOWAIT) == 0) {
350 VM_OBJECT_WLOCK(object);
353 kmem_unback(object, addr, i);
354 return (KERN_NO_SPACE);
356 if (flags & M_ZERO && (m->flags & PG_ZERO) == 0)
358 KASSERT((m->oflags & VPO_UNMANAGED) != 0,
359 ("kmem_malloc: page %p is managed", m));
360 m->valid = VM_PAGE_BITS_ALL;
361 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL,
362 VM_PROT_ALL | PMAP_ENTER_WIRED, 0);
364 VM_OBJECT_WUNLOCK(object);
366 return (KERN_SUCCESS);
372 * Unmap and free the physical pages underlying the specified virtual
375 * A physical page must exist within the specified object at each index
376 * that is being unmapped.
379 kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size)
382 vm_offset_t i, offset;
384 KASSERT(object == kmem_object || object == kernel_object,
385 ("kmem_unback: only supports kernel objects."));
387 pmap_remove(kernel_pmap, addr, addr + size);
388 offset = addr - VM_MIN_KERNEL_ADDRESS;
389 VM_OBJECT_WLOCK(object);
390 for (i = 0; i < size; i += PAGE_SIZE) {
391 m = vm_page_lookup(object, OFF_TO_IDX(offset + i));
392 vm_page_unwire(m, 0);
395 VM_OBJECT_WUNLOCK(object);
401 * Free memory allocated with kmem_malloc. The size must match the
402 * original allocation.
405 kmem_free(struct vmem *vmem, vm_offset_t addr, vm_size_t size)
408 size = round_page(size);
409 kmem_unback((vmem == kmem_arena) ? kmem_object : kernel_object,
411 vmem_free(vmem, addr, size);
417 * Allocates pageable memory from a sub-map of the kernel. If the submap
418 * has no room, the caller sleeps waiting for more memory in the submap.
420 * This routine may block.
423 kmap_alloc_wait(map, size)
429 size = round_page(size);
430 if (!swap_reserve(size))
435 * To make this work for more than one map, use the map's lock
436 * to lock out sleepers/wakers.
439 if (vm_map_findspace(map, vm_map_min(map), size, &addr) == 0)
441 /* no space now; see if we can ever get space */
442 if (vm_map_max(map) - vm_map_min(map) < size) {
447 map->needs_wakeup = TRUE;
448 vm_map_unlock_and_wait(map, 0);
450 vm_map_insert(map, NULL, 0, addr, addr + size, VM_PROT_ALL,
451 VM_PROT_ALL, MAP_ACC_CHARGED);
459 * Returns memory to a submap of the kernel, and wakes up any processes
460 * waiting for memory in that map.
463 kmap_free_wakeup(map, addr, size)
470 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size));
471 if (map->needs_wakeup) {
472 map->needs_wakeup = FALSE;
479 kmem_init_zero_region(void)
485 * Map a single physical page of zeros to a larger virtual range.
486 * This requires less looping in places that want large amounts of
487 * zeros, while not using much more physical resources.
489 addr = kva_alloc(ZERO_REGION_SIZE);
490 m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL |
491 VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO);
492 if ((m->flags & PG_ZERO) == 0)
494 for (i = 0; i < ZERO_REGION_SIZE; i += PAGE_SIZE)
495 pmap_qenter(addr + i, &m, 1);
496 pmap_protect(kernel_pmap, addr, addr + ZERO_REGION_SIZE, VM_PROT_READ);
498 zero_region = (const void *)addr;
504 * Create the kernel map; insert a mapping covering kernel text,
505 * data, bss, and all space allocated thus far (`boostrap' data). The
506 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and
507 * `start' as allocated, and the range between `start' and `end' as free.
510 kmem_init(start, end)
511 vm_offset_t start, end;
515 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
518 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */
520 (void) vm_map_insert(m, NULL, (vm_ooffset_t) 0,
524 VM_MIN_KERNEL_ADDRESS,
526 start, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
527 /* ... and ending with the completion of the above `insert' */
533 * Allow userspace to directly trigger the VM drain routine for testing
537 debug_vm_lowmem(SYSCTL_HANDLER_ARGS)
542 error = sysctl_handle_int(oidp, &i, 0, req);
546 EVENTHANDLER_INVOKE(vm_lowmem, 0);
550 SYSCTL_PROC(_debug, OID_AUTO, vm_lowmem, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
551 debug_vm_lowmem, "I", "set to trigger vm_lowmem event");