freebsd-dev/sys/vm/vm_kern.c
Matthew Dillon 1d58b2bc7d Potential bug fix, do not just clear PG_BUSY... call vm_page_wakeup()
instead to properly handle any waiters.

    Added comments, added support for M_ASLEEP.  Generally treat M_ flags
    as flags instead of constants to compare against.
1999-01-21 09:38:20 +00:00

478 lines
14 KiB
C

/*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)vm_kern.c 8.3 (Berkeley) 1/12/94
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $Id: vm_kern.c,v 1.51 1999/01/21 08:29:10 dillon Exp $
*/
/*
* Kernel memory management.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_prot.h>
#include <sys/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_extern.h>
vm_map_t kernel_map=0;
vm_map_t kmem_map=0;
vm_map_t exec_map=0;
vm_map_t clean_map=0;
vm_map_t u_map=0;
vm_map_t buffer_map=0;
vm_map_t mb_map=0;
int mb_map_full=0;
vm_map_t io_map=0;
vm_map_t phys_map=0;
/*
* kmem_alloc_pageable:
*
* Allocate pageable memory to the kernel's address map.
* "map" must be kernel_map or a submap of kernel_map.
*/
vm_offset_t
kmem_alloc_pageable(map, size)
vm_map_t map;
register vm_size_t size;
{
vm_offset_t addr;
register int result;
size = round_page(size);
addr = vm_map_min(map);
result = vm_map_find(map, NULL, (vm_offset_t) 0,
&addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
if (result != KERN_SUCCESS) {
return (0);
}
return (addr);
}
/*
* Allocate wired-down memory in the kernel's address map
* or a submap.
*/
vm_offset_t
kmem_alloc(map, size)
register vm_map_t map;
register vm_size_t size;
{
vm_offset_t addr;
register vm_offset_t offset;
vm_offset_t i;
size = round_page(size);
/*
* Use the kernel object for wired-down kernel pages. Assume that no
* region of the kernel object is referenced more than once.
*/
/*
* Locate sufficient space in the map. This will give us the final
* virtual address for the new memory, and thus will tell us the
* offset within the kernel map.
*/
vm_map_lock(map);
if (vm_map_findspace(map, vm_map_min(map), size, &addr)) {
vm_map_unlock(map);
return (0);
}
offset = addr - VM_MIN_KERNEL_ADDRESS;
vm_object_reference(kernel_object);
vm_map_insert(map, kernel_object, offset, addr, addr + size,
VM_PROT_ALL, VM_PROT_ALL, 0);
vm_map_unlock(map);
/*
* Guarantee that there are pages already in this object before
* calling vm_map_pageable. This is to prevent the following
* scenario:
*
* 1) Threads have swapped out, so that there is a pager for the
* kernel_object. 2) The kmsg zone is empty, and so we are
* kmem_allocing a new page for it. 3) vm_map_pageable calls vm_fault;
* there is no page, but there is a pager, so we call
* pager_data_request. But the kmsg zone is empty, so we must
* kmem_alloc. 4) goto 1 5) Even if the kmsg zone is not empty: when
* we get the data back from the pager, it will be (very stale)
* non-zero data. kmem_alloc is defined to return zero-filled memory.
*
* We're intentionally not activating the pages we allocate to prevent a
* race with page-out. vm_map_pageable will wire the pages.
*/
for (i = 0; i < size; i += PAGE_SIZE) {
vm_page_t mem;
mem = vm_page_grab(kernel_object, OFF_TO_IDX(offset + i),
VM_ALLOC_ZERO | VM_ALLOC_RETRY);
if ((mem->flags & PG_ZERO) == 0)
vm_page_zero_fill(mem);
mem->valid = VM_PAGE_BITS_ALL;
vm_page_flag_clear(mem, PG_ZERO);
vm_page_wakeup(mem);
}
/*
* And finally, mark the data as non-pageable.
*/
(void) vm_map_pageable(map, (vm_offset_t) addr, addr + size, FALSE);
return (addr);
}
/*
* kmem_free:
*
* Release a region of kernel virtual memory allocated
* with kmem_alloc, and return the physical pages
* associated with that region.
*
* This routine may not block on kernel maps.
*/
void
kmem_free(map, addr, size)
vm_map_t map;
register vm_offset_t addr;
vm_size_t size;
{
(void) vm_map_remove(map, trunc_page(addr), round_page(addr + size));
}
/*
* kmem_suballoc:
*
* Allocates a map to manage a subrange
* of the kernel virtual address space.
*
* Arguments are as follows:
*
* parent Map to take range from
* size Size of range to find
* min, max Returned endpoints of map
* pageable Can the region be paged
*/
vm_map_t
kmem_suballoc(parent, min, max, size)
register vm_map_t parent;
vm_offset_t *min, *max;
register vm_size_t size;
{
register int ret;
vm_map_t result;
size = round_page(size);
*min = (vm_offset_t) vm_map_min(parent);
ret = vm_map_find(parent, NULL, (vm_offset_t) 0,
min, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
if (ret != KERN_SUCCESS) {
printf("kmem_suballoc: bad status return of %d.\n", ret);
panic("kmem_suballoc");
}
*max = *min + size;
pmap_reference(vm_map_pmap(parent));
result = vm_map_create(vm_map_pmap(parent), *min, *max);
if (result == NULL)
panic("kmem_suballoc: cannot create submap");
if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS)
panic("kmem_suballoc: unable to change range to submap");
return (result);
}
/*
* kmem_malloc:
*
* Allocate wired-down memory in the kernel's address map for the higher
* level kernel memory allocator (kern/kern_malloc.c). We cannot use
* kmem_alloc() because we may need to allocate memory at interrupt
* level where we cannot block (canwait == FALSE).
*
* This routine has its own private kernel submap (kmem_map) and object
* (kmem_object). This, combined with the fact that only malloc uses
* this routine, ensures that we will never block in map or object waits.
*
* Note that this still only works in a uni-processor environment and
* when called at splhigh().
*
* We don't worry about expanding the map (adding entries) since entries
* for wired maps are statically allocated.
*
* NOTE: This routine is not supposed to block if M_NOWAIT is set, but
* I have not verified that it actually does not block.
*/
vm_offset_t
kmem_malloc(map, size, flags)
register vm_map_t map;
register vm_size_t size;
int flags;
{
register vm_offset_t offset, i;
vm_map_entry_t entry;
vm_offset_t addr;
vm_page_t m;
if (map != kmem_map && map != mb_map)
panic("kmem_malloc: map != {kmem,mb}_map");
size = round_page(size);
addr = vm_map_min(map);
/*
* Locate sufficient space in the map. This will give us the final
* virtual address for the new memory, and thus will tell us the
* offset within the kernel map.
*/
vm_map_lock(map);
if (vm_map_findspace(map, vm_map_min(map), size, &addr)) {
vm_map_unlock(map);
if (map == mb_map) {
mb_map_full = TRUE;
printf("Out of mbuf clusters - adjust NMBCLUSTERS or increase maxusers!\n");
return (0);
}
if ((flags & M_NOWAIT) == 0)
panic("kmem_malloc(%d): kmem_map too small: %d total allocated",
size, map->size);
return (0);
}
offset = addr - VM_MIN_KERNEL_ADDRESS;
vm_object_reference(kmem_object);
vm_map_insert(map, kmem_object, offset, addr, addr + size,
VM_PROT_ALL, VM_PROT_ALL, 0);
for (i = 0; i < size; i += PAGE_SIZE) {
/*
* Note: if M_NOWAIT specified alone, allocate from
* interrupt-safe queues only (just the free list). If
* M_ASLEEP or M_USE_RESERVE is also specified, we can also
* allocate from the cache. Neither of the latter two
* flags may be specified from an interrupt since interrupts
* are not allowed to mess with the cache queue.
*/
retry:
m = vm_page_alloc(kmem_object, OFF_TO_IDX(offset + i),
((flags & (M_NOWAIT|M_ASLEEP|M_USE_RESERVE)) == M_NOWAIT) ?
VM_ALLOC_INTERRUPT :
VM_ALLOC_SYSTEM);
/*
* Ran out of space, free everything up and return. Don't need
* to lock page queues here as we know that the pages we got
* aren't on any queues.
*/
if (m == NULL) {
if ((flags & M_NOWAIT) == 0) {
VM_WAIT;
goto retry;
}
while (i != 0) {
i -= PAGE_SIZE;
m = vm_page_lookup(kmem_object,
OFF_TO_IDX(offset + i));
vm_page_free(m);
}
vm_map_delete(map, addr, addr + size);
vm_map_unlock(map);
if (flags & M_ASLEEP) {
VM_AWAIT;
}
return (0);
}
vm_page_flag_clear(m, PG_ZERO);
m->valid = VM_PAGE_BITS_ALL;
}
/*
* Mark map entry as non-pageable. Assert: vm_map_insert() will never
* be able to extend the previous entry so there will be a new entry
* exactly corresponding to this address range and it will have
* wired_count == 0.
*/
if (!vm_map_lookup_entry(map, addr, &entry) ||
entry->start != addr || entry->end != addr + size ||
entry->wired_count)
panic("kmem_malloc: entry not found or misaligned");
entry->wired_count++;
vm_map_simplify_entry(map, entry);
/*
* Loop thru pages, entering them in the pmap. (We cannot add them to
* the wired count without wrapping the vm_page_queue_lock in
* splimp...)
*/
for (i = 0; i < size; i += PAGE_SIZE) {
m = vm_page_lookup(kmem_object, OFF_TO_IDX(offset + i));
vm_page_wire(m);
vm_page_wakeup(m);
/*
* Because this is kernel_pmap, this call will not block.
*/
pmap_enter(kernel_pmap, addr + i, VM_PAGE_TO_PHYS(m),
VM_PROT_ALL, 1);
vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED);
}
vm_map_unlock(map);
return (addr);
}
/*
* kmem_alloc_wait:
*
* Allocates pageable memory from a sub-map of the kernel. If the submap
* has no room, the caller sleeps waiting for more memory in the submap.
*
* This routine may block.
*/
vm_offset_t
kmem_alloc_wait(map, size)
vm_map_t map;
vm_size_t size;
{
vm_offset_t addr;
size = round_page(size);
for (;;) {
/*
* To make this work for more than one map, use the map's lock
* to lock out sleepers/wakers.
*/
vm_map_lock(map);
if (vm_map_findspace(map, vm_map_min(map), size, &addr) == 0)
break;
/* no space now; see if we can ever get space */
if (vm_map_max(map) - vm_map_min(map) < size) {
vm_map_unlock(map);
return (0);
}
vm_map_unlock(map);
tsleep(map, PVM, "kmaw", 0);
}
vm_map_insert(map, NULL, (vm_offset_t) 0, addr, addr + size, VM_PROT_ALL, VM_PROT_ALL, 0);
vm_map_unlock(map);
return (addr);
}
/*
* kmem_free_wakeup:
*
* Returns memory to a submap of the kernel, and wakes up any processes
* waiting for memory in that map.
*/
void
kmem_free_wakeup(map, addr, size)
vm_map_t map;
vm_offset_t addr;
vm_size_t size;
{
vm_map_lock(map);
(void) vm_map_delete(map, trunc_page(addr), round_page(addr + size));
wakeup(map);
vm_map_unlock(map);
}
/*
* kmem_init:
*
* Create the kernel map; insert a mapping covering kernel text,
* data, bss, and all space allocated thus far (`boostrap' data). The
* new map will thus map the range between VM_MIN_KERNEL_ADDRESS and
* `start' as allocated, and the range between `start' and `end' as free.
*/
void
kmem_init(start, end)
vm_offset_t start, end;
{
register vm_map_t m;
m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
vm_map_lock(m);
/* N.B.: cannot use kgdb to debug, starting with this assignment ... */
kernel_map = m;
kernel_map->system_map = 1;
(void) vm_map_insert(m, NULL, (vm_offset_t) 0,
VM_MIN_KERNEL_ADDRESS, start, VM_PROT_ALL, VM_PROT_ALL, 0);
/* ... and ending with the completion of the above `insert' */
vm_map_unlock(m);
}