106fdfcb2b
caller to vm_page_grab(). Although this gives VM_ALLOC_ZERO a different meaning for vm_page_grab() than for vm_page_alloc(), I feel such change is necessary to accomplish other goals. Specifically, I want to make the PG_ZERO flag immutable between the time it is allocated by vm_page_alloc() and freed by vm_page_free() or vm_page_free_zero() to avoid locking overheads. Once we gave up on the ability to automatically recognize a zeroed page upon entry to vm_page_free(), the ability to mutate the PG_ZERO flag became useless. Instead, I would like to say that "Once a page becomes valid, its PG_ZERO flag must be ignored."
534 lines
15 KiB
C
534 lines
15 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.
|
|
* 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.
|
|
*/
|
|
|
|
/*
|
|
* Kernel memory management.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h> /* for ticks and hz */
|
|
#include <sys/lock.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/malloc.h>
|
|
|
|
#include <vm/vm.h>
|
|
#include <vm/vm_param.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 pipe_map;
|
|
vm_map_t buffer_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;
|
|
vm_size_t size;
|
|
{
|
|
vm_offset_t addr;
|
|
int result;
|
|
|
|
size = round_page(size);
|
|
addr = vm_map_min(map);
|
|
result = vm_map_find(map, NULL, 0,
|
|
&addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
|
|
if (result != KERN_SUCCESS) {
|
|
return (0);
|
|
}
|
|
return (addr);
|
|
}
|
|
|
|
/*
|
|
* kmem_alloc_nofault:
|
|
*
|
|
* Allocate a virtual address range with no underlying object and
|
|
* no initial mapping to physical memory. Any mapping from this
|
|
* range to physical memory must be explicitly created prior to
|
|
* its use, typically with pmap_qenter(). Any attempt to create
|
|
* a mapping on demand through vm_fault() will result in a panic.
|
|
*/
|
|
vm_offset_t
|
|
kmem_alloc_nofault(map, size)
|
|
vm_map_t map;
|
|
vm_size_t size;
|
|
{
|
|
vm_offset_t addr;
|
|
int result;
|
|
|
|
size = round_page(size);
|
|
addr = vm_map_min(map);
|
|
result = vm_map_find(map, NULL, 0,
|
|
&addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
|
|
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)
|
|
vm_map_t map;
|
|
vm_size_t size;
|
|
{
|
|
vm_offset_t addr;
|
|
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_wire. 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_wire 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_wire will wire the pages.
|
|
*/
|
|
VM_OBJECT_LOCK(kernel_object);
|
|
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);
|
|
mem->valid = VM_PAGE_BITS_ALL;
|
|
vm_page_lock_queues();
|
|
vm_page_unmanage(mem);
|
|
vm_page_wakeup(mem);
|
|
vm_page_unlock_queues();
|
|
}
|
|
VM_OBJECT_UNLOCK(kernel_object);
|
|
|
|
/*
|
|
* And finally, mark the data as non-pageable.
|
|
*/
|
|
(void) vm_map_wire(map, addr, addr + size,
|
|
VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES);
|
|
|
|
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;
|
|
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
|
|
* min, max Returned endpoints of map
|
|
* size Size of range to find
|
|
*/
|
|
vm_map_t
|
|
kmem_suballoc(parent, min, max, size)
|
|
vm_map_t parent;
|
|
vm_offset_t *min, *max;
|
|
vm_size_t size;
|
|
{
|
|
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;
|
|
result = vm_map_create(vm_map_pmap(parent), *min, *max);
|
|
if (result == NULL)
|
|
panic("kmem_suballoc: cannot create submap");
|
|
if (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.
|
|
*
|
|
* `map' is ONLY allowed to be kmem_map or one of the mbuf submaps to
|
|
* which we never free.
|
|
*/
|
|
vm_offset_t
|
|
kmem_malloc(map, size, flags)
|
|
vm_map_t map;
|
|
vm_size_t size;
|
|
int flags;
|
|
{
|
|
vm_offset_t offset, i;
|
|
vm_map_entry_t entry;
|
|
vm_offset_t addr;
|
|
vm_page_t m;
|
|
int pflags;
|
|
|
|
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 != kmem_map) {
|
|
static int last_report; /* when we did it (in ticks) */
|
|
if (ticks < last_report ||
|
|
(ticks - last_report) >= hz) {
|
|
last_report = ticks;
|
|
printf("Out of mbuf address space!\n");
|
|
printf("Consider increasing NMBCLUSTERS\n");
|
|
}
|
|
return (0);
|
|
}
|
|
if ((flags & M_NOWAIT) == 0)
|
|
panic("kmem_malloc(%ld): kmem_map too small: %ld total allocated",
|
|
(long)size, (long)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);
|
|
|
|
/*
|
|
* Note: if M_NOWAIT specified alone, allocate from
|
|
* interrupt-safe queues only (just the free list). If
|
|
* 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.
|
|
*/
|
|
|
|
if ((flags & (M_NOWAIT|M_USE_RESERVE)) == M_NOWAIT)
|
|
pflags = VM_ALLOC_INTERRUPT | VM_ALLOC_WIRED;
|
|
else
|
|
pflags = VM_ALLOC_SYSTEM | VM_ALLOC_WIRED;
|
|
|
|
if (flags & M_ZERO)
|
|
pflags |= VM_ALLOC_ZERO;
|
|
|
|
VM_OBJECT_LOCK(kmem_object);
|
|
for (i = 0; i < size; i += PAGE_SIZE) {
|
|
retry:
|
|
m = vm_page_alloc(kmem_object, OFF_TO_IDX(offset + i), pflags);
|
|
|
|
/*
|
|
* 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_OBJECT_UNLOCK(kmem_object);
|
|
vm_map_unlock(map);
|
|
VM_WAIT;
|
|
vm_map_lock(map);
|
|
VM_OBJECT_LOCK(kmem_object);
|
|
goto retry;
|
|
}
|
|
/*
|
|
* Free the pages before removing the map entry.
|
|
* They are already marked busy. Calling
|
|
* vm_map_delete before the pages has been freed or
|
|
* unbusied will cause a deadlock.
|
|
*/
|
|
while (i != 0) {
|
|
i -= PAGE_SIZE;
|
|
m = vm_page_lookup(kmem_object,
|
|
OFF_TO_IDX(offset + i));
|
|
vm_page_lock_queues();
|
|
vm_page_unwire(m, 0);
|
|
vm_page_free(m);
|
|
vm_page_unlock_queues();
|
|
}
|
|
VM_OBJECT_UNLOCK(kmem_object);
|
|
vm_map_delete(map, addr, addr + size);
|
|
vm_map_unlock(map);
|
|
return (0);
|
|
}
|
|
if (flags & M_ZERO && (m->flags & PG_ZERO) == 0)
|
|
pmap_zero_page(m);
|
|
m->valid = VM_PAGE_BITS_ALL;
|
|
vm_page_lock_queues();
|
|
vm_page_unmanage(m);
|
|
vm_page_unlock_queues();
|
|
}
|
|
VM_OBJECT_UNLOCK(kmem_object);
|
|
|
|
/*
|
|
* 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 != 0)
|
|
panic("kmem_malloc: entry not found or misaligned");
|
|
entry->wired_count = 1;
|
|
|
|
/*
|
|
* At this point, the kmem_object must be unlocked because
|
|
* vm_map_simplify_entry() calls vm_object_deallocate(), which
|
|
* locks the kmem_object.
|
|
*/
|
|
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...)
|
|
*/
|
|
VM_OBJECT_LOCK(kmem_object);
|
|
for (i = 0; i < size; i += PAGE_SIZE) {
|
|
m = vm_page_lookup(kmem_object, OFF_TO_IDX(offset + i));
|
|
/*
|
|
* Because this is kernel_pmap, this call will not block.
|
|
*/
|
|
pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 1);
|
|
vm_page_lock_queues();
|
|
vm_page_flag_set(m, PG_WRITEABLE | PG_REFERENCED);
|
|
vm_page_wakeup(m);
|
|
vm_page_unlock_queues();
|
|
}
|
|
VM_OBJECT_UNLOCK(kmem_object);
|
|
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);
|
|
}
|
|
map->needs_wakeup = TRUE;
|
|
vm_map_unlock_and_wait(map, FALSE);
|
|
}
|
|
vm_map_insert(map, NULL, 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));
|
|
if (map->needs_wakeup) {
|
|
map->needs_wakeup = FALSE;
|
|
vm_map_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;
|
|
{
|
|
vm_map_t m;
|
|
|
|
m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
|
|
m->system_map = 1;
|
|
vm_map_lock(m);
|
|
/* N.B.: cannot use kgdb to debug, starting with this assignment ... */
|
|
kernel_map = m;
|
|
(void) vm_map_insert(m, NULL, (vm_ooffset_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);
|
|
}
|