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1. Remove a rather strangely gratuitous bit of profanity
[unix-history] / sys / vm / vm_page.c
/*
* Copyright (c) 1991 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_page.c 7.4 (Berkeley) 5/7/91
* $Id: vm_page.c,v 1.17 1994/04/20 07:07:14 davidg Exp $
*/
/*
* 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.
*/
/*
* Resident memory management module.
*/
#include "param.h"
#include "systm.h"
#include "vm.h"
#include "vm_map.h"
#include "vm_page.h"
#include "vm_pageout.h"
#include "proc.h"
/*
* Associated with page of user-allocatable memory is a
* page structure.
*/
queue_head_t *vm_page_buckets; /* Array of buckets */
int vm_page_bucket_count = 0; /* How big is array? */
int vm_page_hash_mask; /* Mask for hash function */
simple_lock_data_t bucket_lock; /* lock for all buckets XXX */
queue_head_t vm_page_queue_free;
queue_head_t vm_page_queue_active;
queue_head_t vm_page_queue_inactive;
simple_lock_data_t vm_page_queue_lock;
simple_lock_data_t vm_page_queue_free_lock;
vm_page_t vm_page_array;
long first_page;
long last_page;
vm_offset_t first_phys_addr;
vm_offset_t last_phys_addr;
int vm_page_free_count;
int vm_page_active_count;
int vm_page_inactive_count;
int vm_page_wire_count;
int vm_page_laundry_count;
int vm_page_count;
extern int vm_pageout_pages_needed;
int vm_page_free_target = 0;
int vm_page_free_min = 0;
int vm_page_inactive_target = 0;
int vm_page_free_reserved = 0;
vm_size_t page_size = PAGE_SIZE;
/*
* vm_page_startup:
*
* Initializes the resident memory module.
*
* Allocates memory for the page cells, and
* for the object/offset-to-page hash table headers.
* Each page cell is initialized and placed on the free list.
*/
vm_offset_t
vm_page_startup(starta, enda, vaddr)
register vm_offset_t starta;
vm_offset_t enda;
register vm_offset_t vaddr;
{
register vm_offset_t mapped;
register vm_page_t m;
register queue_t bucket;
vm_size_t npages, page_range;
register vm_offset_t new_start;
int i;
vm_offset_t pa;
int nblocks;
vm_offset_t first_managed_page;
int size;
extern vm_offset_t kentry_data;
extern vm_size_t kentry_data_size;
extern vm_offset_t phys_avail[];
/* the biggest memory array is the second group of pages */
vm_offset_t start;
vm_offset_t biggestone, biggestsize;
vm_offset_t total;
total = 0;
biggestsize = 0;
biggestone = 0;
nblocks = 0;
vaddr = round_page(vaddr);
for (i = 0; phys_avail[i + 1]; i += 2) {
phys_avail[i] = round_page(phys_avail[i]);
phys_avail[i+1] = trunc_page(phys_avail[i+1]);
}
for (i = 0; phys_avail[i + 1]; i += 2) {
int size = phys_avail[i+1] - phys_avail[i];
if (size > biggestsize) {
biggestone = i;
biggestsize = size;
}
++nblocks;
total += size;
}
start = phys_avail[biggestone];
/*
* Initialize the locks
*/
simple_lock_init(&vm_page_queue_free_lock);
simple_lock_init(&vm_page_queue_lock);
/*
* Initialize the queue headers for the free queue,
* the active queue and the inactive queue.
*/
queue_init(&vm_page_queue_free);
queue_init(&vm_page_queue_active);
queue_init(&vm_page_queue_inactive);
/*
* Allocate (and initialize) the hash table buckets.
*
* The number of buckets MUST BE a power of 2, and
* the actual value is the next power of 2 greater
* than the number of physical pages in the system.
*
* Note:
* This computation can be tweaked if desired.
*/
vm_page_buckets = (queue_t) vaddr;
bucket = vm_page_buckets;
if (vm_page_bucket_count == 0) {
vm_page_bucket_count = 1;
while (vm_page_bucket_count < atop(total))
vm_page_bucket_count <<= 1;
}
vm_page_hash_mask = vm_page_bucket_count - 1;
/*
* Validate these addresses.
*/
new_start = start + vm_page_bucket_count * sizeof(struct queue_entry);
new_start = round_page(new_start);
mapped = vaddr;
vaddr = pmap_map(mapped, start, new_start,
VM_PROT_READ|VM_PROT_WRITE);
start = new_start;
bzero((caddr_t) mapped, vaddr - mapped);
mapped = vaddr;
for (i = 0; i< vm_page_bucket_count; i++) {
queue_init(bucket);
bucket++;
}
simple_lock_init(&bucket_lock);
/*
* round (or truncate) the addresses to our page size.
*/
/*
* Pre-allocate maps and map entries that cannot be dynamically
* allocated via malloc(). The maps include the kernel_map and
* kmem_map which must be initialized before malloc() will
* work (obviously). Also could include pager maps which would
* be allocated before kmeminit.
*
* Allow some kernel map entries... this should be plenty
* since people shouldn't be cluttering up the kernel
* map (they should use their own maps).
*/
kentry_data_size = MAX_KMAP * sizeof(struct vm_map) +
MAX_KMAPENT * sizeof(struct vm_map_entry);
kentry_data_size = round_page(kentry_data_size);
kentry_data = (vm_offset_t) vaddr;
vaddr += kentry_data_size;
/*
* Validate these zone addresses.
*/
new_start = start + (vaddr - mapped);
pmap_map(mapped, start, new_start, VM_PROT_READ|VM_PROT_WRITE);
bzero((caddr_t) mapped, (vaddr - mapped));
start = round_page(new_start);
/*
* Compute the number of pages of memory that will be
* available for use (taking into account the overhead
* of a page structure per page).
*/
npages = (total - (start - phys_avail[biggestone])) / (PAGE_SIZE + sizeof(struct vm_page));
first_page = phys_avail[0] / PAGE_SIZE;
page_range = (phys_avail[(nblocks-1)*2 + 1] - phys_avail[0]) / PAGE_SIZE;
/*
* Initialize the mem entry structures now, and
* put them in the free queue.
*/
vm_page_array = (vm_page_t) vaddr;
mapped = vaddr;
/*
* Validate these addresses.
*/
new_start = round_page(start + page_range * sizeof (struct vm_page));
mapped = pmap_map(mapped, start, new_start,
VM_PROT_READ|VM_PROT_WRITE);
start = new_start;
first_managed_page = start / PAGE_SIZE;
/*
* Clear all of the page structures
*/
bzero((caddr_t)vm_page_array, page_range * sizeof(struct vm_page));
vm_page_count = 0;
vm_page_free_count = 0;
for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) {
if (i == biggestone)
pa = ptoa(first_managed_page);
else
pa = phys_avail[i];
while (pa < phys_avail[i + 1] && npages-- > 0) {
++vm_page_count;
++vm_page_free_count;
m = PHYS_TO_VM_PAGE(pa);
m->flags = 0;
m->object = 0;
m->phys_addr = pa;
m->hold_count = 0;
queue_enter(&vm_page_queue_free, m, vm_page_t, pageq);
pa += PAGE_SIZE;
}
}
/*
* Initialize vm_pages_needed lock here - don't wait for pageout
* daemon XXX
*/
simple_lock_init(&vm_pages_needed_lock);
return(mapped);
}
/*
* vm_page_hash:
*
* Distributes the object/offset key pair among hash buckets.
*
* NOTE: This macro depends on vm_page_bucket_count being a power of 2.
*/
inline const int
vm_page_hash(object, offset)
vm_object_t object;
vm_offset_t offset;
{
return ((unsigned)object + offset/NBPG) & vm_page_hash_mask;
}
/*
* vm_page_insert: [ internal use only ]
*
* Inserts the given mem entry into the object/object-page
* table and object list.
*
* The object and page must be locked.
* interrupts must be disable in this routine!!!
*/
void
vm_page_insert(mem, object, offset)
register vm_page_t mem;
register vm_object_t object;
register vm_offset_t offset;
{
register queue_t bucket;
int spl;
VM_PAGE_CHECK(mem);
if (mem->flags & PG_TABLED)
panic("vm_page_insert: already inserted");
/*
* Record the object/offset pair in this page
*/
mem->object = object;
mem->offset = offset;
/*
* Insert it into the object_object/offset hash table
*/
bucket = &vm_page_buckets[vm_page_hash(object, offset)];
simple_lock(&bucket_lock);
queue_enter(bucket, mem, vm_page_t, hashq);
simple_unlock(&bucket_lock);
/*
* Now link into the object's list of backed pages.
*/
queue_enter(&object->memq, mem, vm_page_t, listq);
mem->flags |= PG_TABLED;
/*
* And show that the object has one more resident
* page.
*/
object->resident_page_count++;
}
/*
* vm_page_remove: [ internal use only ]
*
* Removes the given mem entry from the object/offset-page
* table and the object page list.
*
* The object and page must be locked.
*
* interrupts must be disable in this routine!!!
*/
void
vm_page_remove(mem)
register vm_page_t mem;
{
register queue_t bucket;
int spl;
VM_PAGE_CHECK(mem);
if (!(mem->flags & PG_TABLED)) {
printf("page not tabled?????\n");
return;
}
/*
* Remove from the object_object/offset hash table
*/
bucket = &vm_page_buckets[vm_page_hash(mem->object, mem->offset)];
simple_lock(&bucket_lock);
queue_remove(bucket, mem, vm_page_t, hashq);
simple_unlock(&bucket_lock);
/*
* Now remove from the object's list of backed pages.
*/
queue_remove(&mem->object->memq, mem, vm_page_t, listq);
/*
* And show that the object has one fewer resident
* page.
*/
mem->object->resident_page_count--;
mem->object = 0;
mem->flags &= ~PG_TABLED;
}
/*
* vm_page_lookup:
*
* Returns the page associated with the object/offset
* pair specified; if none is found, NULL is returned.
*
* The object must be locked. No side effects.
*/
vm_page_t
vm_page_lookup(object, offset)
register vm_object_t object;
register vm_offset_t offset;
{
register vm_page_t mem;
register queue_t bucket;
int spl;
/*
* Search the hash table for this object/offset pair
*/
bucket = &vm_page_buckets[vm_page_hash(object, offset)];
spl = splimp();
simple_lock(&bucket_lock);
mem = (vm_page_t) queue_first(bucket);
while (!queue_end(bucket, (queue_entry_t) mem)) {
VM_PAGE_CHECK(mem);
if ((mem->object == object) && (mem->offset == offset)) {
simple_unlock(&bucket_lock);
splx(spl);
return(mem);
}
mem = (vm_page_t) queue_next(&mem->hashq);
}
simple_unlock(&bucket_lock);
splx(spl);
return(NULL);
}
/*
* vm_page_rename:
*
* Move the given memory entry from its
* current object to the specified target object/offset.
*
* The object must be locked.
*/
void
vm_page_rename(mem, new_object, new_offset)
register vm_page_t mem;
register vm_object_t new_object;
vm_offset_t new_offset;
{
int spl;
if (mem->object == new_object)
return;
vm_page_lock_queues(); /* keep page from moving out from
under pageout daemon */
spl = splimp();
vm_page_remove(mem);
vm_page_insert(mem, new_object, new_offset);
splx(spl);
vm_page_unlock_queues();
}
/*
* vm_page_alloc:
*
* Allocate and return a memory cell associated
* with this VM object/offset pair.
*
* Object must be locked.
*/
vm_page_t
vm_page_alloc(object, offset)
vm_object_t object;
vm_offset_t offset;
{
register vm_page_t mem;
int spl;
spl = splimp();
simple_lock(&vm_page_queue_free_lock);
if ( object != kernel_object &&
object != kmem_object &&
curproc != pageproc && curproc != &proc0 &&
vm_page_free_count < vm_page_free_reserved) {
simple_unlock(&vm_page_queue_free_lock);
splx(spl);
/*
* this wakeup seems unnecessary, but there is code that
* might just check to see if there are free pages, and
* punt if there aren't. VM_WAIT does this too, but
* redundant wakeups aren't that bad...
*/
if (curproc != pageproc)
wakeup((caddr_t) &vm_pages_needed);
return(NULL);
}
if (queue_empty(&vm_page_queue_free)) {
simple_unlock(&vm_page_queue_free_lock);
splx(spl);
/*
* comment above re: wakeups applies here too...
*/
if (curproc != pageproc)
wakeup((caddr_t) &vm_pages_needed);
return(NULL);
}
queue_remove_first(&vm_page_queue_free, mem, vm_page_t, pageq);
vm_page_free_count--;
simple_unlock(&vm_page_queue_free_lock);
mem->flags = PG_BUSY|PG_CLEAN|PG_FAKE;
vm_page_insert(mem, object, offset);
mem->wire_count = 0;
mem->hold_count = 0;
mem->act_count = 0;
splx(spl);
/*
* don't wakeup too often, so we wakeup the pageout daemon when
* we would be nearly out of memory.
*/
if (curproc != pageproc &&
(vm_page_free_count < vm_page_free_reserved))
wakeup((caddr_t) &vm_pages_needed);
return(mem);
}
/*
* vm_page_free:
*
* Returns the given page to the free list,
* disassociating it with any VM object.
*
* Object and page must be locked prior to entry.
*/
void
vm_page_free(mem)
register vm_page_t mem;
{
int spl;
spl = splimp();
vm_page_remove(mem);
if (mem->flags & PG_ACTIVE) {
queue_remove(&vm_page_queue_active, mem, vm_page_t, pageq);
mem->flags &= ~PG_ACTIVE;
vm_page_active_count--;
}
if (mem->flags & PG_INACTIVE) {
queue_remove(&vm_page_queue_inactive, mem, vm_page_t, pageq);
mem->flags &= ~PG_INACTIVE;
vm_page_inactive_count--;
}
if (!(mem->flags & PG_FICTITIOUS)) {
simple_lock(&vm_page_queue_free_lock);
if (mem->wire_count) {
vm_page_wire_count--;
mem->wire_count = 0;
}
queue_enter(&vm_page_queue_free, mem, vm_page_t, pageq);
vm_page_free_count++;
simple_unlock(&vm_page_queue_free_lock);
splx(spl);
/*
* if pageout daemon needs pages, then tell it that there
* are some free.
*/
if (vm_pageout_pages_needed)
wakeup((caddr_t)&vm_pageout_pages_needed);
/*
* wakeup processes that are waiting on memory if we
* hit a high water mark.
*/
if (vm_page_free_count == vm_page_free_min) {
wakeup((caddr_t)&vm_page_free_count);
}
/*
* wakeup scheduler process if we have lots of memory.
* this process will swapin processes.
*/
if (vm_page_free_count == vm_page_free_target) {
wakeup((caddr_t)&proc0);
}
} else {
splx(spl);
}
wakeup((caddr_t) mem);
}
/*
* vm_page_wire:
*
* Mark this page as wired down by yet
* another map, removing it from paging queues
* as necessary.
*
* The page queues must be locked.
*/
void
vm_page_wire(mem)
register vm_page_t mem;
{
int spl;
VM_PAGE_CHECK(mem);
spl = splimp();
if (mem->wire_count == 0) {
if (mem->flags & PG_ACTIVE) {
queue_remove(&vm_page_queue_active, mem, vm_page_t,
pageq);
vm_page_active_count--;
mem->flags &= ~PG_ACTIVE;
}
if (mem->flags & PG_INACTIVE) {
queue_remove(&vm_page_queue_inactive, mem, vm_page_t,
pageq);
vm_page_inactive_count--;
mem->flags &= ~PG_INACTIVE;
}
vm_page_wire_count++;
}
mem->wire_count++;
splx(spl);
}
/*
* vm_page_unwire:
*
* Release one wiring of this page, potentially
* enabling it to be paged again.
*
* The page queues must be locked.
*/
void
vm_page_unwire(mem)
register vm_page_t mem;
{
int spl;
VM_PAGE_CHECK(mem);
spl = splimp();
if (mem->wire_count != 0)
mem->wire_count--;
if (mem->wire_count == 0) {
queue_enter(&vm_page_queue_active, mem, vm_page_t, pageq);
vm_page_active_count++;
mem->flags |= PG_ACTIVE;
vm_page_wire_count--;
}
splx(spl);
}
/*
* vm_page_deactivate:
*
* Returns the given page to the inactive list,
* indicating that no physical maps have access
* to this page. [Used by the physical mapping system.]
*
* The page queues must be locked.
*/
void
vm_page_deactivate(m)
register vm_page_t m;
{
int spl;
VM_PAGE_CHECK(m);
/*
* Only move active pages -- ignore locked or already
* inactive ones.
*
* XXX: sometimes we get pages which aren't wired down
* or on any queue - we need to put them on the inactive
* queue also, otherwise we lose track of them.
* Paul Mackerras (paulus@cs.anu.edu.au) 9-Jan-93.
*/
spl = splimp();
if (!(m->flags & PG_INACTIVE) && m->wire_count == 0 && m->hold_count == 0) {
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
if (m->flags & PG_ACTIVE) {
queue_remove(&vm_page_queue_active, m, vm_page_t, pageq);
m->flags &= ~PG_ACTIVE;
vm_page_active_count--;
}
queue_enter(&vm_page_queue_inactive, m, vm_page_t, pageq);
m->flags |= PG_INACTIVE;
vm_page_inactive_count++;
#define NOT_DEACTIVATE_PROTECTS
#ifndef NOT_DEACTIVATE_PROTECTS
pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_NONE);
#else
if (pmap_is_modified(VM_PAGE_TO_PHYS(m)))
m->flags &= ~PG_CLEAN;
#endif
if ((m->flags & PG_CLEAN) == 0)
m->flags |= PG_LAUNDRY;
}
splx(spl);
}
/*
* vm_page_makefault
*
* Cause next access of this page to fault
*/
void
vm_page_makefault(m)
vm_page_t m;
{
pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_NONE);
if ((m->flags & PG_CLEAN) == 0)
m->flags |= PG_LAUNDRY;
}
/*
* vm_page_activate:
*
* Put the specified page on the active list (if appropriate).
*
* The page queues must be locked.
*/
void
vm_page_activate(m)
register vm_page_t m;
{
int spl, target, shortage, maxscan;
vm_page_t actm, next;
VM_PAGE_CHECK(m);
spl = splimp();
if (m->wire_count) {
splx(spl);
return;
}
if ((m->flags & (PG_INACTIVE|PG_ACTIVE)) ==
(PG_INACTIVE|PG_ACTIVE)) {
panic("vm_page_activate: on both queues?");
}
if (m->flags & PG_INACTIVE) {
queue_remove(&vm_page_queue_inactive, m, vm_page_t, pageq);
vm_page_inactive_count--;
m->flags &= ~PG_INACTIVE;
vm_stat.reactivations++;
}
if (m->flags & PG_ACTIVE)
panic("vm_page_activate: already active");
m->flags |= PG_ACTIVE;
queue_enter(&vm_page_queue_active, m, vm_page_t, pageq);
queue_remove(&m->object->memq, m, vm_page_t, listq);
queue_enter(&m->object->memq, m, vm_page_t, listq);
vm_page_active_count++;
/* m->act_count = 10; */
m->act_count = 1;
splx(spl);
}
/*
* vm_page_zero_fill:
*
* Zero-fill the specified page.
* Written as a standard pagein routine, to
* be used by the zero-fill object.
*/
boolean_t
vm_page_zero_fill(m)
vm_page_t m;
{
VM_PAGE_CHECK(m);
pmap_zero_page(VM_PAGE_TO_PHYS(m));
return(TRUE);
}
/*
* vm_page_copy:
*
* Copy one page to another
*/
void
vm_page_copy(src_m, dest_m)
vm_page_t src_m;
vm_page_t dest_m;
{
VM_PAGE_CHECK(src_m);
VM_PAGE_CHECK(dest_m);
pmap_copy_page(VM_PAGE_TO_PHYS(src_m), VM_PAGE_TO_PHYS(dest_m));
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.