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7fc0fd1f47
freebsd-skq/sys/vm/vm_pageout.c
dg 7fc0fd1f47 swap_pager.c: 
Fixed long standing bug in freeing swap space during object collapses.
Fixed 'out of space' messages from printing out too often.
Modified to use new kmem_malloc() calling convention.
Implemented an additional stat in the swap pager struct to count the
amount of space allocated to that pager. This may be removed at some
point in the future.
Minimized unnecessary wakeups.

vm_fault.c:
Don't try to collect fault stats on 'swapped' processes - there aren't
any upages to store the stats in.
Changed read-ahead policy (again!).

vm_glue.c:
Be sure to gain a reference to the process's map before swapping.
Be sure to lose it when done.

kern_malloc.c:
Added the ability to specify if allocations are at interrupt time or
are 'safe'; this affects what types of pages can be allocated.

vm_map.c:
Fixed a variety of map lock problems; there's still a lurking bug that
will eventually bite.

vm_object.c:
Explicitly initialize the object fields rather than bzeroing the struct.
Eliminated the 'rcollapse' code and folded it's functionality into the
"real" collapse routine.
Moved an object_unlock() so that the backing_object is protected in
the qcollapse routine.
Make sure nobody fools with the backing_object when we're destroying it.
Added some diagnostic code which can be called from the debugger that
looks through all the internal objects and makes certain that they
all belong to someone.

vm_page.c:
Fixed a rather serious logic bug that would result in random system
crashes. Changed pagedaemon wakeup policy (again!).

vm_pageout.c:
Removed unnecessary page rotations on the inactive queue.
Changed the number of pages to explicitly free to just free_reserved
level.

Submitted by:	John Dyson
1995-02-02 09:09:15 +00:00

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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 1.32 1995/01/28 02:02:25 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 <sys/kernel.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_pages_needed = 0;/* flag saying that the pageout daemon needs pages */
int vm_page_pagesfreed;
extern int npendingio;
int vm_pageout_proc_limit;
int vm_pageout_req_swapout;
int vm_daemon_needed;
extern int nswiodone;
extern int swap_pager_full;
extern int vm_swap_size;
extern int swap_pager_ready();
#define MAXREF 32767
#define MAXSCAN 512 /* maximum number of pages to scan in active queue */
#define ACT_DECLINE 1
#define ACT_ADVANCE 3
#define ACT_MAX 100
#define MAXISCAN 256
#define MINTOFREE 6
#define MINFREE 2
#define MAXLAUNDER (cnt.v_page_count > 1800 ? 32 : 16)
#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;
}
if (!object->pager && (object->flags & OBJ_INTERNAL) == 0) {
printf("pager: non internal obj without pager\n");
}
/*
* 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 + cnt.v_cache_count) < cnt.v_pageout_free_min)
return 0;
if ((!sync && m->bmapped != 0 && m->hold_count != 0) ||
((m->busy != 0) || (m->flags & PG_BUSY)))
return 0;
if (!sync && object->shadow) {
vm_object_collapse(object);
}
pageout_count = 1;
ms[0] = m;
pager = object->pager;
if (pager) {
for (i = 1; i < vm_pageout_page_count; i++) {
vm_page_t mt;
ms[i] = mt = vm_page_lookup(object, offset + i * NBPG);
if (mt) {
vm_page_test_dirty(mt);
/*
* we can cluster ONLY if: ->> the page is NOT
* busy, and is NOT clean the page is not
* wired, busy, held, or mapped into a buffer.
* and one of the following: 1) The page is
* inactive, or a seldom used active page. 2)
* or we force the issue.
*/
if ((mt->dirty & mt->valid) != 0
&& (((mt->flags & (PG_BUSY | PG_INACTIVE)) == PG_INACTIVE)
|| sync == VM_PAGEOUT_FORCE)
&& (mt->wire_count == 0)
&& (mt->busy == 0)
&& (mt->hold_count == 0)
&& (mt->bmapped == 0))
pageout_count++;
else
break;
} else
break;
}
/*
* we allow reads during pageouts...
*/
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 + cnt.v_cache_count) >= cnt.v_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:
++anyok;
break;
case VM_PAGER_PEND:
++anyok;
break;
case VM_PAGER_BAD:
/*
* Page outside of range of object. Right now we
* essentially lose the changes by pretending it
* worked.
*/
pmap_clear_modify(VM_PAGE_TO_PHYS(ms[i]));
ms[i]->dirty = 0;
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, map_remove_only)
vm_map_t map;
vm_object_t object;
int count;
int map_remove_only;
{
register vm_page_t p, next;
int rcount;
int dcount;
dcount = 0;
if (count == 0)
count = 1;
if (object->pager && (object->pager->pg_type == PG_DEVICE))
return 0;
if (object->shadow) {
if (object->shadow->ref_count == 1)
dcount += vm_pageout_object_deactivate_pages(map, object->shadow, count / 2 + 1, map_remove_only);
else
vm_pageout_object_deactivate_pages(map, object->shadow, count, 1);
}
if (object->paging_in_progress || !vm_object_lock_try(object))
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 (p->wire_count != 0 ||
p->hold_count != 0 ||
p->bmapped != 0 ||
p->busy != 0 ||
!pmap_page_exists(vm_map_pmap(map), VM_PAGE_TO_PHYS(p))) {
p = next;
continue;
}
/*
* 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) {
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) {
if (!map_remove_only)
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();
vm_object_unlock(object);
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);
}
} else if ((p->flags & (PG_INACTIVE | PG_BUSY)) == PG_INACTIVE) {
pmap_page_protect(VM_PAGE_TO_PHYS(p),
VM_PROT_NONE);
}
vm_page_unlock_queues();
p = next;
}
vm_object_unlock(object);
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, 0);
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, 0);
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;
}
void
vm_req_vmdaemon()
{
extern int ticks;
static int lastrun = 0;
if ((ticks > (lastrun + hz / 10)) || (ticks < lastrun)) {
wakeup((caddr_t) &vm_daemon_needed);
lastrun = ticks;
}
}
void
vm_pageout_inactive_stats(int maxiscan)
{
vm_page_t m;
int s;
if (maxiscan > cnt.v_inactive_count)
maxiscan = cnt.v_inactive_count;
m = vm_page_queue_inactive.tqh_first;
while (m && (maxiscan-- > 0)) {
vm_page_t next;
next = m->pageq.tqe_next;
if (((m->flags & PG_REFERENCED) == 0) &&
pmap_is_referenced(VM_PAGE_TO_PHYS(m))) {
m->flags |= PG_REFERENCED;
}
if (m->object->ref_count == 0) {
m->flags &= ~PG_REFERENCED;
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
}
if (m->flags & PG_REFERENCED) {
m->flags &= ~PG_REFERENCED;
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
vm_page_activate(m);
/*
* heuristic alert -- if a page is being re-activated,
* it probably will be used one more time...
*/
if (m->act_count < ACT_MAX)
m->act_count += ACT_ADVANCE;
}
m = next;
}
}
/*
* 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, *bigproc;
vm_offset_t size, bigsize;
vm_object_t object;
int force_wakeup = 0;
int cache_size, orig_cache_size;
int minscan;
int mintofree;
#ifdef LFS
lfs_reclaim_buffers();
#endif
/* calculate the total cached size */
if ((cnt.v_inactive_count + cnt.v_free_count + cnt.v_cache_count) <
(cnt.v_inactive_target + cnt.v_free_min)) {
vm_req_vmdaemon();
}
/*
* now swap processes out if we are in low memory conditions
*/
if ((cnt.v_free_count <= cnt.v_free_min) &&
!swap_pager_full && vm_swap_size && vm_pageout_req_swapout == 0) {
vm_pageout_req_swapout = 1;
vm_req_vmdaemon();
}
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.
*/
rescan0:
vm_pageout_inactive_stats(MAXISCAN);
maxlaunder = (cnt.v_inactive_target > MAXLAUNDER) ?
MAXLAUNDER : cnt.v_inactive_target;
rescan1:
maxscan = cnt.v_inactive_count;
mintofree = MINTOFREE;
m = vm_page_queue_inactive.tqh_first;
while (m &&
(maxscan-- > 0) &&
(((cnt.v_free_count + cnt.v_cache_count) < desired_free) ||
(--mintofree > 0))) {
vm_page_t next;
cnt.v_pdpages++;
next = m->pageq.tqe_next;
#if defined(VM_DIAGNOSE)
if ((m->flags & PG_INACTIVE) == 0) {
printf("vm_pageout_scan: page not inactive?\n");
break;
}
#endif
/*
* dont mess with busy pages
*/
if (m->hold_count || m->busy || (m->flags & PG_BUSY) ||
m->bmapped != 0) {
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
m = next;
continue;
}
if (((m->flags & PG_REFERENCED) == 0) &&
pmap_is_referenced(VM_PAGE_TO_PHYS(m))) {
m->flags |= PG_REFERENCED;
}
if (m->object->ref_count == 0) {
m->flags &= ~PG_REFERENCED;
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
}
if ((m->flags & PG_REFERENCED) != 0) {
m->flags &= ~PG_REFERENCED;
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
vm_page_activate(m);
if (m->act_count < ACT_MAX)
m->act_count += ACT_ADVANCE;
m = next;
continue;
}
vm_page_test_dirty(m);
if ((m->dirty & m->valid) == 0) {
if (m->valid == 0) {
pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_NONE);
vm_page_free(m);
} else if (((cnt.v_free_count + cnt.v_cache_count) < desired_free) ||
(cnt.v_cache_count < cnt.v_cache_min)) {
vm_page_cache(m);
}
} else if (maxlaunder > 0) {
int written;
object = m->object;
if ((object->flags & OBJ_DEAD) || !vm_object_lock_try(object)) {
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);
vm_object_unlock(object);
if (!next) {
break;
}
maxlaunder -= written;
/*
* if the next page has been re-activated, start
* scanning again
*/
if ((next->flags & PG_INACTIVE) == 0) {
goto rescan1;
}
}
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 + cnt.v_cache_count);
if (page_shortage <= 0) {
if (pages_freed == 0) {
if ((cnt.v_free_count + cnt.v_cache_count) < desired_free) {
page_shortage =
desired_free - (cnt.v_free_count + cnt.v_cache_count);
}
}
if( (page_shortage <= 0) && (cnt.v_free_count < cnt.v_free_min))
page_shortage = 1;
}
maxscan = cnt.v_active_count;
minscan = cnt.v_active_count;
if (minscan > MAXSCAN)
minscan = MAXSCAN;
m = vm_page_queue_active.tqh_first;
while (m && ((maxscan > 0 && (page_shortage > 0)) || minscan > 0)) {
if (maxscan)
--maxscan;
if (minscan)
--minscan;
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->bmapped != 0)) {
TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
m = next;
continue;
}
if (m->object->ref_count && ((m->flags & PG_REFERENCED) ||
pmap_is_referenced(VM_PAGE_TO_PHYS(m)))) {
int s;
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);
s = splhigh();
TAILQ_REMOVE(&m->object->memq, m, listq);
TAILQ_INSERT_TAIL(&m->object->memq, m, listq);
splx(s);
} else {
m->flags &= ~PG_REFERENCED;
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
m->act_count -= min(m->act_count, ACT_DECLINE);
/*
* if the page act_count is zero -- then we deactivate
*/
if (!m->act_count && (page_shortage > 0)) {
if (m->object->ref_count == 0) {
vm_page_test_dirty(m);
--page_shortage;
if ((m->dirty & m->valid) == 0) {
m->act_count = 0;
vm_page_cache(m);
} else {
vm_page_deactivate(m);
}
} else {
vm_page_deactivate(m);
--page_shortage;
}
} else if (m->act_count) {
TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
}
}
m = next;
}
/*
* We try to maintain some *really* free pages, this allows interrupt
* code to be guaranteed space.
*/
while (cnt.v_free_count < cnt.v_free_reserved) {
m = vm_page_queue_cache.tqh_first;
if (!m)
break;
vm_page_free(m);
}
/*
* make sure that we have swap space -- if we are low on memory and
* swap -- then kill the biggest process.
*/
if ((vm_swap_size == 0 || swap_pager_full) &&
((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min)) {
bigproc = NULL;
bigsize = 0;
for (p = (struct proc *) allproc; p != NULL; p = p->p_next) {
/*
* if this is a system process, skip it
*/
if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) ||
((p->p_pid < 48) && (vm_swap_size != 0))) {
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 the process size
*/
size = p->p_vmspace->vm_pmap.pm_stats.resident_count;
/*
* if the this process is bigger than the biggest one
* remember it.
*/
if (size > bigsize) {
bigproc = p;
bigsize = size;
}
}
if (bigproc != NULL) {
printf("Process %lu killed by vm_pageout -- out of swap\n", (u_long) bigproc->p_pid);
psignal(bigproc, SIGKILL);
bigproc->p_estcpu = 0;
bigproc->p_nice = PRIO_MIN;
resetpriority(bigproc);
wakeup((caddr_t) &cnt.v_free_count);
}
}
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.
*/
if (cnt.v_page_count > 1024)
cnt.v_free_min = 4 + (cnt.v_page_count - 1024) / 200;
else
cnt.v_free_min = 4;
/*
* free_reserved needs to include enough for the largest swap pager
* structures plus enough for any pv_entry structs when paging.
*/
cnt.v_pageout_free_min = 6 + cnt.v_page_count / 1024;
cnt.v_free_reserved = cnt.v_pageout_free_min + 2;
cnt.v_free_target = 3 * cnt.v_free_min + cnt.v_free_reserved;
cnt.v_inactive_target = cnt.v_free_count / 4;
if (cnt.v_inactive_target > 512)
cnt.v_inactive_target = 512;
cnt.v_free_min += cnt.v_free_reserved;
if (cnt.v_page_count > 1024) {
cnt.v_cache_max = (cnt.v_free_count - 1024) / 2;
cnt.v_cache_min = (cnt.v_free_count - 1024) / 20;
} else {
cnt.v_cache_min = 0;
cnt.v_cache_max = 0;
}
/* 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) {
tsleep((caddr_t) &vm_pages_needed, PVM, "psleep", 0);
cnt.v_pdwakeups++;
vm_pager_sync();
vm_pageout_scan();
vm_pager_sync();
wakeup((caddr_t) &cnt.v_free_count);
wakeup((caddr_t) kmem_map);
}
}
void
vm_daemon()
{
int cache_size;
vm_object_t object;
struct proc *p;
while (TRUE) {
tsleep((caddr_t) &vm_daemon_needed, PUSER, "psleep", 0);
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) {
int overage;
quad_t limit;
vm_offset_t size;
/*
* 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; /* XXX */
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);
}
}
}
/*
* we remove cached objects that have no RSS...
*/
restart:
vm_object_cache_lock();
object = vm_object_cached_list.tqh_first;
while (object) {
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_cache_trim: I'm sooo confused.");
pager_cache(object, FALSE);
goto restart;
}
object = object->cached_list.tqe_next;
vm_object_cache_lock();
}
vm_object_cache_unlock();
}
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