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freebsd-nq/sys/vm/vm_pageout.c

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/*
* Copyright (c) 1991 Regents of the University of California.
* All rights reserved.
* Copyright (c) 1994 John S. Dyson
* All rights reserved.
* Copyright (c) 1994 David Greenman
* 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_pageout.c 7.4 (Berkeley) 5/7/91
*
*
* 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_pageout.c,v 1.18 1994/10/15 13:33:08 davidg Exp $
*/
/*
* The proverbial page-out daemon.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/malloc.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/swap_pager.h>
extern vm_map_t kmem_map;
int vm_pages_needed; /* Event on which pageout daemon sleeps */
int vm_pagescanner; /* Event on which pagescanner sleeps */
int vm_pageout_free_min = 0; /* Stop pageout to wait for pagers at this free level */
int vm_pageout_pages_needed = 0; /* flag saying that the pageout daemon needs pages */
int vm_page_pagesfreed;
int vm_desired_cache_size;
extern int npendingio;
extern int hz;
int vm_pageout_proc_limit;
extern int nswiodone;
extern int swap_pager_full;
extern int swap_pager_ready();
#define MAXREF 32767
#define MAXSCAN 512 /* maximum number of pages to scan in active queue */
/* set the "clock" hands to be (MAXSCAN * 4096) Bytes */
#define ACT_DECLINE 1
#define ACT_ADVANCE 3
#define ACT_MAX 100
#define LOWATER ((2048*1024)/NBPG)
#define VM_PAGEOUT_PAGE_COUNT 8
int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT;
int vm_pageout_req_do_stats;
int vm_page_max_wired = 0; /* XXX max # of wired pages system-wide */
/*
* vm_pageout_clean:
* cleans a vm_page
*/
int
vm_pageout_clean(m, sync)
register vm_page_t m;
int sync;
{
/*
* Clean the page and remove it from the
* laundry.
*
* We set the busy bit to cause
* potential page faults on this page to
* block.
*
* And we set pageout-in-progress to keep
* the object from disappearing during
* pageout. This guarantees that the
* page won't move from the inactive
* queue. (However, any other page on
* the inactive queue may move!)
*/
register vm_object_t object;
register vm_pager_t pager;
int pageout_status[VM_PAGEOUT_PAGE_COUNT];
vm_page_t ms[VM_PAGEOUT_PAGE_COUNT];
int pageout_count;
int anyok=0;
int i;
vm_offset_t offset = m->offset;
object = m->object;
if (!object) {
printf("pager: object missing\n");
return 0;
}
/*
* Try to collapse the object before
* making a pager for it. We must
* unlock the page queues first.
* We try to defer the creation of a pager
* until all shadows are not paging. This
* allows vm_object_collapse to work better and
* helps control swap space size.
* (J. Dyson 11 Nov 93)
*/
if (!object->pager &&
cnt.v_free_count < vm_pageout_free_min)
return 0;
if (!object->pager &&
object->shadow &&
object->shadow->paging_in_progress)
return 0;
if( !sync) {
if (object->shadow) {
vm_object_collapse(object);
if (!vm_page_lookup(object, offset))
return 0;
}
if ((m->busy != 0) ||
(m->flags & PG_BUSY) || (m->hold_count != 0)) {
return 0;
}
}
pageout_count = 1;
ms[0] = m;
pager = object->pager;
if (pager) {
for (i = 1; i < vm_pageout_page_count; i++) {
ms[i] = vm_page_lookup(object, offset+i*NBPG);
if (ms[i]) {
if (( ((ms[i]->flags & (PG_CLEAN|PG_INACTIVE|PG_BUSY)) == PG_INACTIVE)
|| ( (ms[i]->flags & (PG_CLEAN|PG_BUSY)) == 0 && sync == VM_PAGEOUT_FORCE))
&& (ms[i]->wire_count == 0)
&& (ms[i]->busy == 0)
&& (ms[i]->hold_count == 0))
pageout_count++;
else
break;
} else
break;
}
for(i=0;i<pageout_count;i++) {
ms[i]->flags |= PG_BUSY;
pmap_page_protect(VM_PAGE_TO_PHYS(ms[i]), VM_PROT_READ);
}
object->paging_in_progress += pageout_count;
} else {
m->flags |= PG_BUSY;
pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_READ);
object->paging_in_progress++;
pager = vm_pager_allocate(PG_DFLT, (caddr_t)0,
object->size, VM_PROT_ALL, 0);
if (pager != NULL) {
vm_object_setpager(object, pager, 0, FALSE);
}
}
/*
* If there is no pager for the page,
* use the default pager. If there's
* no place to put the page at the
* moment, leave it in the laundry and
* hope that there will be paging space
* later.
*/
if ((pager && pager->pg_type == PG_SWAP) ||
cnt.v_free_count >= vm_pageout_free_min) {
if( pageout_count == 1) {
pageout_status[0] = pager ?
vm_pager_put(pager, m,
((sync || (object == kernel_object)) ? TRUE: FALSE)) :
VM_PAGER_FAIL;
} else {
if( !pager) {
for(i=0;i<pageout_count;i++)
pageout_status[i] = VM_PAGER_FAIL;
} else {
vm_pager_put_pages(pager, ms, pageout_count,
((sync || (object == kernel_object)) ? TRUE : FALSE),
pageout_status);
}
}
} else {
for(i=0;i<pageout_count;i++)
pageout_status[i] = VM_PAGER_FAIL;
}
for(i=0;i<pageout_count;i++) {
switch (pageout_status[i]) {
case VM_PAGER_OK:
ms[i]->flags &= ~PG_LAUNDRY;
++anyok;
break;
case VM_PAGER_PEND:
ms[i]->flags &= ~PG_LAUNDRY;
++anyok;
break;
case VM_PAGER_BAD:
/*
* Page outside of range of object.
* Right now we essentially lose the
* changes by pretending it worked.
*/
ms[i]->flags &= ~PG_LAUNDRY;
ms[i]->flags |= PG_CLEAN;
pmap_clear_modify(VM_PAGE_TO_PHYS(ms[i]));
break;
case VM_PAGER_ERROR:
case VM_PAGER_FAIL:
/*
* If page couldn't be paged out, then
* reactivate the page so it doesn't
* clog the inactive list. (We will
* try paging out it again later).
*/
if (ms[i]->flags & PG_INACTIVE)
vm_page_activate(ms[i]);
break;
case VM_PAGER_AGAIN:
break;
}
/*
* If the operation is still going, leave
* the page busy to block all other accesses.
* Also, leave the paging in progress
* indicator set so that we don't attempt an
* object collapse.
*/
if (pageout_status[i] != VM_PAGER_PEND) {
PAGE_WAKEUP(ms[i]);
if (--object->paging_in_progress == 0)
wakeup((caddr_t) object);
if ((ms[i]->flags & PG_REFERENCED) ||
pmap_is_referenced(VM_PAGE_TO_PHYS(ms[i]))) {
pmap_clear_reference(VM_PAGE_TO_PHYS(ms[i]));
ms[i]->flags &= ~PG_REFERENCED;
if( ms[i]->flags & PG_INACTIVE)
vm_page_activate(ms[i]);
}
}
}
return anyok;
}
/*
* vm_pageout_object_deactivate_pages
*
* deactivate enough pages to satisfy the inactive target
* requirements or if vm_page_proc_limit is set, then
* deactivate all of the pages in the object and its
* shadows.
*
* The object and map must be locked.
*/
int
vm_pageout_object_deactivate_pages(map, object, count)
vm_map_t map;
vm_object_t object;
int count;
{
register vm_page_t p, next;
int rcount;
int dcount;
dcount = 0;
if (count == 0)
count = 1;
if (object->shadow) {
int scount = count;
if( object->shadow->ref_count > 1)
scount /= object->shadow->ref_count;
if( scount)
dcount += vm_pageout_object_deactivate_pages(map, object->shadow, scount);
}
if (object->paging_in_progress)
return dcount;
/*
* scan the objects entire memory queue
*/
rcount = object->resident_page_count;
p = object->memq.tqh_first;
while (p && (rcount-- > 0)) {
next = p->listq.tqe_next;
cnt.v_pdpages++;
vm_page_lock_queues();
/*
* if a page is active, not wired and is in the processes pmap,
* then deactivate the page.
*/
if ((p->flags & (PG_ACTIVE|PG_BUSY)) == PG_ACTIVE &&
p->wire_count == 0 &&
p->hold_count == 0 &&
p->busy == 0 &&
pmap_page_exists(vm_map_pmap(map), VM_PAGE_TO_PHYS(p))) {
if (!pmap_is_referenced(VM_PAGE_TO_PHYS(p)) &&
(p->flags & PG_REFERENCED) == 0) {
p->act_count -= min(p->act_count, ACT_DECLINE);
/*
* if the page act_count is zero -- then we deactivate
*/
if (!p->act_count) {
vm_page_deactivate(p);
pmap_page_protect(VM_PAGE_TO_PHYS(p),
VM_PROT_NONE);
/*
* else if on the next go-around we will deactivate the page
* we need to place the page on the end of the queue to age
* the other pages in memory.
*/
} else {
TAILQ_REMOVE(&vm_page_queue_active, p, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq);
TAILQ_REMOVE(&object->memq, p, listq);
TAILQ_INSERT_TAIL(&object->memq, p, listq);
}
/*
* see if we are done yet
*/
if (p->flags & PG_INACTIVE) {
--count;
++dcount;
if (count <= 0 &&
cnt.v_inactive_count > cnt.v_inactive_target) {
vm_page_unlock_queues();
return dcount;
}
}
} else {
/*
* Move the page to the bottom of the queue.
*/
pmap_clear_reference(VM_PAGE_TO_PHYS(p));
p->flags &= ~PG_REFERENCED;
if (p->act_count < ACT_MAX)
p->act_count += ACT_ADVANCE;
TAILQ_REMOVE(&vm_page_queue_active, p, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq);
TAILQ_REMOVE(&object->memq, p, listq);
TAILQ_INSERT_TAIL(&object->memq, p, listq);
}
}
vm_page_unlock_queues();
p = next;
}
return dcount;
}
/*
* deactivate some number of pages in a map, try to do it fairly, but
* that is really hard to do.
*/
void
vm_pageout_map_deactivate_pages(map, entry, count, freeer)
vm_map_t map;
vm_map_entry_t entry;
int *count;
int (*freeer)(vm_map_t, vm_object_t, int);
{
vm_map_t tmpm;
vm_map_entry_t tmpe;
vm_object_t obj;
if (*count <= 0)
return;
vm_map_reference(map);
if (!lock_try_read(&map->lock)) {
vm_map_deallocate(map);
return;
}
if (entry == 0) {
tmpe = map->header.next;
while (tmpe != &map->header && *count > 0) {
vm_pageout_map_deactivate_pages(map, tmpe, count, freeer);
tmpe = tmpe->next;
};
} else if (entry->is_sub_map || entry->is_a_map) {
tmpm = entry->object.share_map;
tmpe = tmpm->header.next;
while (tmpe != &tmpm->header && *count > 0) {
vm_pageout_map_deactivate_pages(tmpm, tmpe, count, freeer);
tmpe = tmpe->next;
};
} else if ((obj = entry->object.vm_object) != 0) {
*count -= (*freeer)(map, obj, *count);
}
lock_read_done(&map->lock);
vm_map_deallocate(map);
return;
}
/*
* vm_pageout_scan does the dirty work for the pageout daemon.
*/
int
vm_pageout_scan()
{
vm_page_t m;
int page_shortage, maxscan, maxlaunder;
int pages_freed;
int desired_free;
vm_page_t next;
struct proc *p;
vm_object_t object;
int force_wakeup = 0;
int cache_size, orig_cache_size;
/*
* We manage the cached memory by attempting to keep it
* at about the desired level.
* We deactivate the pages for the oldest cached objects
* first. This keeps pages that are "cached" from hogging
* physical memory.
*/
orig_cache_size = 0;
object = vm_object_cached_list.tqh_first;
/* calculate the total cached size */
while( object) {
orig_cache_size += object->resident_page_count;
object = object->cached_list.tqe_next;
}
redeact:
cache_size = orig_cache_size;
object = vm_object_cached_list.tqh_first;
vm_object_cache_lock();
while ( object && (cnt.v_inactive_count < cnt.v_inactive_target) &&
(cache_size >= vm_desired_cache_size)) {
vm_object_cache_unlock();
/*
* if there are no resident pages -- get rid of the object
*/
if( object->resident_page_count == 0) {
if (object != vm_object_lookup(object->pager))
panic("vm_object_deactivate: I'm sooo confused.");
pager_cache(object, FALSE);
goto redeact;
} else {
/*
* if there are resident pages -- deactivate them
*/
vm_object_deactivate_pages(object);
cache_size -= object->resident_page_count;
object = object->cached_list.tqe_next;
}
vm_object_cache_lock();
}
vm_object_cache_unlock();
morefree:
/*
* now swap processes out if we are in low memory conditions
*/
if (cnt.v_free_count <= cnt.v_free_min) {
/*
* swap out inactive processes
*/
swapout_threads();
}
/*
* scan the processes for exceeding their rlimits or if process
* is swapped out -- deactivate pages
*/
for (p = (struct proc *)allproc; p != NULL; p = p->p_next) {
vm_offset_t size;
int overage;
quad_t limit;
/*
* if this is a system process or if we have already
* looked at this process, skip it.
*/
if (p->p_flag & (P_SYSTEM|P_WEXIT)) {
continue;
}
/*
* if the process is in a non-running type state,
* don't touch it.
*/
if (p->p_stat != SRUN && p->p_stat != SSLEEP) {
continue;
}
/*
* get a limit
*/
limit = qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur,
p->p_rlimit[RLIMIT_RSS].rlim_max);
/*
* let processes that are swapped out really be swapped out
* set the limit to nothing (will force a swap-out.)
*/
if ((p->p_flag & P_INMEM) == 0)
limit = 0;
size = p->p_vmspace->vm_pmap.pm_stats.resident_count * NBPG;
if (limit >= 0 && size >= limit) {
overage = (size - limit) / NBPG;
vm_pageout_map_deactivate_pages(&p->p_vmspace->vm_map,
(vm_map_entry_t) 0, &overage, vm_pageout_object_deactivate_pages);
}
}
if (((cnt.v_free_count + cnt.v_inactive_count) >=
(cnt.v_inactive_target + cnt.v_free_target)) &&
(cnt.v_free_count >= cnt.v_free_target))
return force_wakeup;
pages_freed = 0;
desired_free = cnt.v_free_target;
/*
* Start scanning the inactive queue for pages we can free.
* We keep scanning until we have enough free pages or
* we have scanned through the entire queue. If we
* encounter dirty pages, we start cleaning them.
*/
maxlaunder = (cnt.v_free_target - cnt.v_free_count);
maxscan = cnt.v_inactive_count;
rescan1:
m = vm_page_queue_inactive.tqh_first;
while (m && (maxscan-- > 0) &&
(cnt.v_free_count < desired_free) ) {
vm_page_t next;
cnt.v_pdpages++;
next = m->pageq.tqe_next;
if( (m->flags & PG_INACTIVE) == 0) {
printf("vm_pageout_scan: page not inactive?");
continue;
}
/*
* activate held pages
*/
if (m->hold_count != 0) {
vm_page_activate(m);
m = next;
continue;
}
/*
* dont mess with busy pages
*/
if (m->busy || (m->flags & PG_BUSY)) {
m = next;
continue;
}
/*
* NOTE: PG_CLEAN doesn't guarantee that the page is clean.
*/
if (m->flags & PG_CLEAN) {
/*
* If we're not low on memory and the page has been reference,
* or if the page has been modified, then reactivate the page.
*/
if (((cnt.v_free_count > vm_pageout_free_min) &&
(pmap_is_referenced(VM_PAGE_TO_PHYS(m)) || ((m->flags & PG_REFERENCED) != 0))) ||
pmap_is_modified(VM_PAGE_TO_PHYS(m))) {
m->flags &= ~PG_REFERENCED;
vm_page_activate(m);
} else if (!m->act_count) {
pmap_page_protect(VM_PAGE_TO_PHYS(m),
VM_PROT_NONE);
vm_page_free(m);
++cnt.v_dfree;
++pages_freed;
} else {
m->act_count -= min(m->act_count, ACT_DECLINE);
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
}
} else if ((m->flags & PG_LAUNDRY) && maxlaunder > 0) {
int written;
if (pmap_is_referenced(VM_PAGE_TO_PHYS(m)) ||
((m->flags & PG_REFERENCED) != 0)) {
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
vm_page_activate(m);
m->flags &= ~PG_REFERENCED;
m = next;
continue;
}
/*
* If a page is dirty, then it is either
* being washed (but not yet cleaned)
* or it is still in the laundry. If it is
* still in the laundry, then we start the
* cleaning operation.
*/
written = vm_pageout_clean(m,0);
if (written)
maxlaunder -= written;
if (!next)
break;
/*
* if the next page has been re-activated, start scanning again
*/
if ((next->flags & PG_INACTIVE) == 0)
goto rescan1;
} else if ((m->flags & PG_REFERENCED) ||
pmap_is_referenced(VM_PAGE_TO_PHYS(m))) {
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
m->flags &= ~PG_REFERENCED;
vm_page_activate(m);
}
m = next;
}
/*
* Compute the page shortage. If we are still very low on memory
* be sure that we will move a minimal amount of pages from active
* to inactive.
*/
page_shortage = cnt.v_inactive_target -
(cnt.v_free_count + cnt.v_inactive_count);
if (page_shortage <= 0) {
if (pages_freed == 0) {
if( cnt.v_free_count < cnt.v_free_min) {
page_shortage = cnt.v_free_min - cnt.v_free_count;
} else if(((cnt.v_free_count + cnt.v_inactive_count) <
(cnt.v_free_min + cnt.v_inactive_target))) {
page_shortage = 1;
} else {
page_shortage = 0;
}
}
}
maxscan = cnt.v_active_count;
m = vm_page_queue_active.tqh_first;
while (m && maxscan-- && (page_shortage > 0)) {
cnt.v_pdpages++;
next = m->pageq.tqe_next;
/*
* Don't deactivate pages that are busy.
*/
if ((m->busy != 0) ||
(m->flags & PG_BUSY) || (m->hold_count != 0)) {
m = next;
continue;
}
if ((m->flags & PG_REFERENCED) ||
pmap_is_referenced(VM_PAGE_TO_PHYS(m))) {
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
m->flags &= ~PG_REFERENCED;
if (m->act_count < ACT_MAX)
m->act_count += ACT_ADVANCE;
TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
TAILQ_REMOVE(&m->object->memq, m, listq);
TAILQ_INSERT_TAIL(&m->object->memq, m, listq);
} else {
m->act_count -= min(m->act_count, ACT_DECLINE);
/*
* if the page act_count is zero -- then we deactivate
*/
if (!m->act_count) {
vm_page_deactivate(m);
--page_shortage;
/*
* else if on the next go-around we will deactivate the page
* we need to place the page on the end of the queue to age
* the other pages in memory.
*/
} else {
TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
TAILQ_REMOVE(&m->object->memq, m, listq);
TAILQ_INSERT_TAIL(&m->object->memq, m, listq);
}
}
m = next;
}
/*
* if we have not freed any pages and we are desparate for memory
* then we keep trying until we get some (any) memory.
*/
if( !force_wakeup && (swap_pager_full || !force_wakeup ||
(pages_freed == 0 && (cnt.v_free_count < cnt.v_free_min)))){
vm_pager_sync();
force_wakeup = 1;
goto morefree;
}
vm_page_pagesfreed += pages_freed;
return force_wakeup;
}
/*
* vm_pageout is the high level pageout daemon.
*/
void
vm_pageout()
{
(void) spl0();
/*
* Initialize some paging parameters.
*/
cnt.v_free_min = 12;
/*
* free_reserved needs to include enough for the largest
* swap pager structures plus enough for any pv_entry
* structs when paging.
*/
cnt.v_free_reserved = 4 + cnt.v_page_count / 1024;
if (cnt.v_free_min < 8)
cnt.v_free_min = 8;
if (cnt.v_free_min > 32)
cnt.v_free_min = 32;
vm_pageout_free_min = cnt.v_free_reserved;
cnt.v_free_target = 2*cnt.v_free_min + cnt.v_free_reserved;
cnt.v_inactive_target = cnt.v_free_count / 12;
cnt.v_free_min += cnt.v_free_reserved;
vm_desired_cache_size = cnt.v_page_count / 3;
/* XXX does not really belong here */
if (vm_page_max_wired == 0)
vm_page_max_wired = cnt.v_free_count / 3;
(void) swap_pager_alloc(0, 0, 0, 0);
/*
* The pageout daemon is never done, so loop
* forever.
*/
while (TRUE) {
int force_wakeup;
/*
cnt.v_free_min = 12 + averunnable.ldavg[0] / 1024;
cnt.v_free_target = 2*cnt.v_free_min + cnt.v_free_reserved;
cnt.v_inactive_target = cnt.v_free_target*2;
*/
tsleep((caddr_t) &vm_pages_needed, PVM, "psleep", 0);
cnt.v_pdwakeups++;
vm_pager_sync();
/*
* The force wakeup hack added to eliminate delays and potiential
* deadlock. It was possible for the page daemon to indefintely
* postpone waking up a process that it might be waiting for memory
* on. The putmulti stuff seems to have aggravated the situation.
*/
force_wakeup = vm_pageout_scan();
vm_pager_sync();
if( force_wakeup)
wakeup( (caddr_t) &cnt.v_free_count);
wakeup((caddr_t) kmem_map);
}
}
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