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HardenedBSD/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 1.57 1995/10/07 19:02:55 davidg Exp $
*/
/*
* The proverbial page-out daemon.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/signalvar.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_kern.h>
#include <vm/vm_pager.h>
#include <vm/swap_pager.h>
/*
* System initialization
*/
/* the kernel process "vm_pageout"*/
static void vm_pageout __P((void));
struct proc *pageproc;
static struct kproc_desc page_kp = {
"pagedaemon",
vm_pageout,
&pageproc
};
SYSINIT_KT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, kproc_start, &page_kp)
/* the kernel process "vm_daemon"*/
static void vm_daemon __P((void));
struct proc *vmproc;
static struct kproc_desc vm_kp = {
"vmdaemon",
vm_daemon,
&vmproc
};
SYSINIT_KT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp)
int vm_pages_needed; /* Event on which pageout daemon sleeps */
int vm_pageout_pages_needed; /* flag saying that the pageout daemon needs pages */
extern int npendingio;
int vm_pageout_req_swapout; /* XXX */
int vm_daemon_needed;
extern int nswiodone;
extern int vm_swap_size;
extern int vfs_update_wakeup;
#define MAXSCAN 1024 /* maximum number of pages to scan in queues */
#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_page_max_wired; /* XXX max # of wired pages system-wide */
typedef int freeer_fcn_t __P((vm_map_t, vm_object_t, int, int));
static void vm_pageout_map_deactivate_pages __P((vm_map_t, vm_map_entry_t,
int *, freeer_fcn_t *));
static freeer_fcn_t vm_pageout_object_deactivate_pages;
static void vm_req_vmdaemon __P((void));
/*
* vm_pageout_clean:
*
* 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!)
*/
int
vm_pageout_clean(m, sync)
vm_page_t m;
int sync;
{
register vm_object_t object;
int pageout_status[VM_PAGEOUT_PAGE_COUNT];
vm_page_t mc[2*VM_PAGEOUT_PAGE_COUNT];
int pageout_count;
int anyok = 0;
int i, forward_okay, backward_okay, page_base;
vm_offset_t offset = m->offset;
object = m->object;
/*
* If not OBJT_SWAP, additional memory may be needed to do the pageout.
* Try to avoid the deadlock.
*/
if ((sync != VM_PAGEOUT_FORCE) &&
(object->type != OBJT_SWAP) &&
((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min))
return 0;
/*
* Don't mess with the page if it's busy.
*/
if ((!sync && m->hold_count != 0) ||
((m->busy != 0) || (m->flags & PG_BUSY)))
return 0;
/*
* Try collapsing before it's too late.
*/
if (!sync && object->backing_object) {
vm_object_collapse(object);
}
mc[VM_PAGEOUT_PAGE_COUNT] = m;
pageout_count = 1;
page_base = VM_PAGEOUT_PAGE_COUNT;
forward_okay = TRUE;
if (offset != 0)
backward_okay = TRUE;
else
backward_okay = FALSE;
/*
* Scan object for clusterable pages.
*
* We can cluster ONLY if: ->> the page is NOT
* clean, wired, busy, held, or mapped into a
* buffer, and one of the following:
* 1) The page is inactive, or a seldom used
* active page.
* -or-
* 2) we force the issue.
*/
for (i = 1; (i < vm_pageout_page_count) && (forward_okay || backward_okay); i++) {
vm_page_t p;
/*
* See if forward page is clusterable.
*/
if (forward_okay) {
/*
* Stop forward scan at end of object.
*/
if ((offset + i * PAGE_SIZE) > object->size) {
forward_okay = FALSE;
goto do_backward;
}
p = vm_page_lookup(object, offset + i * PAGE_SIZE);
if (p) {
if ((p->flags & (PG_BUSY|PG_CACHE)) || p->busy) {
forward_okay = FALSE;
goto do_backward;
}
vm_page_test_dirty(p);
if ((p->dirty & p->valid) != 0 &&
((p->flags & PG_INACTIVE) ||
(sync == VM_PAGEOUT_FORCE)) &&
(p->wire_count == 0) &&
(p->hold_count == 0)) {
mc[VM_PAGEOUT_PAGE_COUNT + i] = p;
pageout_count++;
if (pageout_count == vm_pageout_page_count)
break;
} else {
forward_okay = FALSE;
}
} else {
forward_okay = FALSE;
}
}
do_backward:
/*
* See if backward page is clusterable.
*/
if (backward_okay) {
/*
* Stop backward scan at beginning of object.
*/
if ((offset - i * PAGE_SIZE) == 0) {
backward_okay = FALSE;
}
p = vm_page_lookup(object, offset - i * PAGE_SIZE);
if (p) {
if ((p->flags & (PG_BUSY|PG_CACHE)) || p->busy) {
backward_okay = FALSE;
continue;
}
vm_page_test_dirty(p);
if ((p->dirty & p->valid) != 0 &&
((p->flags & PG_INACTIVE) ||
(sync == VM_PAGEOUT_FORCE)) &&
(p->wire_count == 0) &&
(p->hold_count == 0)) {
mc[VM_PAGEOUT_PAGE_COUNT - i] = p;
pageout_count++;
page_base--;
if (pageout_count == vm_pageout_page_count)
break;
} else {
backward_okay = FALSE;
}
} else {
backward_okay = FALSE;
}
}
}
/*
* we allow reads during pageouts...
*/
for (i = page_base; i < (page_base + pageout_count); i++) {
mc[i]->flags |= PG_BUSY;
vm_page_protect(mc[i], VM_PROT_READ);
}
object->paging_in_progress += pageout_count;
vm_pager_put_pages(object, &mc[page_base], pageout_count,
((sync || (object == kernel_object)) ? TRUE : FALSE),
pageout_status);
for (i = 0; i < pageout_count; i++) {
vm_page_t mt = mc[page_base + 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(mt));
mt->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 (mt->flags & PG_INACTIVE)
vm_page_activate(mt);
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) {
vm_object_pip_wakeup(object);
if ((mt->flags & (PG_REFERENCED|PG_WANTED)) ||
pmap_is_referenced(VM_PAGE_TO_PHYS(mt))) {
pmap_clear_reference(VM_PAGE_TO_PHYS(mt));
mt->flags &= ~PG_REFERENCED;
if (mt->flags & PG_INACTIVE)
vm_page_activate(mt);
}
PAGE_WAKEUP(mt);
}
}
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
* backing_objects.
*
* The object and map must be locked.
*/
static 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->type == OBJT_DEVICE)
return 0;
if (object->backing_object) {
if (object->backing_object->ref_count == 1)
dcount += vm_pageout_object_deactivate_pages(map,
object->backing_object, count / 2 + 1, map_remove_only);
else
vm_pageout_object_deactivate_pages(map,
object->backing_object, count, 1);
}
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++;
if (p->wire_count != 0 ||
p->hold_count != 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|PG_WANTED)) == 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);
vm_page_protect(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);
}
/*
* see if we are done yet
*/
if (p->flags & PG_INACTIVE) {
--count;
++dcount;
if (count <= 0 &&
cnt.v_inactive_count > cnt.v_inactive_target) {
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);
}
} else if ((p->flags & (PG_INACTIVE | PG_BUSY)) == PG_INACTIVE) {
vm_page_protect(p, VM_PROT_NONE);
}
p = next;
}
return dcount;
}
/*
* deactivate some number of pages in a map, try to do it fairly, but
* that is really hard to do.
*/
static void
vm_pageout_map_deactivate_pages(map, entry, count, freeer)
vm_map_t map;
vm_map_entry_t entry;
int *count;
freeer_fcn_t *freeer;
{
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, TRUE);
}
lock_read_done(&map->lock);
vm_map_deallocate(map);
return;
}
static void
vm_req_vmdaemon()
{
static int lastrun = 0;
if ((ticks > (lastrun + hz / 10)) || (ticks < lastrun)) {
wakeup(&vm_daemon_needed);
lastrun = ticks;
}
}
/*
* vm_pageout_scan does the dirty work for the pageout daemon.
*/
int
vm_pageout_scan()
{
vm_page_t m;
int page_shortage, maxscan, maxlaunder, pcount;
int pages_freed;
vm_page_t next;
struct proc *p, *bigproc;
vm_offset_t size, bigsize;
vm_object_t object;
int force_wakeup = 0;
int vnodes_skipped = 0;
pages_freed = 0;
/*
* 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_inactive_target > MAXLAUNDER) ?
MAXLAUNDER : cnt.v_inactive_target;
rescan1:
maxscan = cnt.v_inactive_count;
m = vm_page_queue_inactive.tqh_first;
while ((m != NULL) && (maxscan-- > 0) &&
((cnt.v_cache_count + cnt.v_free_count) < (cnt.v_cache_min + cnt.v_free_target))) {
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)) {
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|PG_WANTED)) != 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 == 0) {
if (m->bmapped == 0) {
if (m->valid == 0) {
pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_NONE);
vm_page_free(m);
cnt.v_dfree++;
} else {
vm_page_cache(m);
}
++pages_freed;
} else {
m = next;
continue;
}
} else if (maxlaunder > 0) {
int written;
struct vnode *vp = NULL;
object = m->object;
if (object->flags & OBJ_DEAD) {
m = next;
continue;
}
if (object->type == OBJT_VNODE) {
vp = object->handle;
if (VOP_ISLOCKED(vp) || vget(vp, 1)) {
if (object->flags & OBJ_WRITEABLE)
++vnodes_skipped;
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 (vp)
vput(vp);
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) {
page_shortage = cnt.v_free_min - cnt.v_free_count;
} else {
page_shortage = 1;
}
}
maxscan = MAXSCAN;
pcount = cnt.v_active_count;
m = vm_page_queue_active.tqh_first;
while ((m != NULL) && (maxscan > 0) && (pcount-- > 0) && (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)) {
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|PG_WANTED)) ||
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);
} 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) {
--page_shortage;
vm_page_test_dirty(m);
if ((m->bmapped == 0) && (m->dirty == 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);
}
}
maxscan--;
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);
cnt.v_dfree++;
}
/*
* If we didn't get enough free pages, and we have skipped a vnode
* in a writeable object, wakeup the sync daemon. And kick swapout
* if we did not get enough free pages.
*/
if ((cnt.v_cache_count + cnt.v_free_count) < cnt.v_free_target) {
if (vnodes_skipped &&
(cnt.v_cache_count + cnt.v_free_count) < cnt.v_free_min) {
if (!vfs_update_wakeup) {
vfs_update_wakeup = 1;
wakeup(&vfs_update_wakeup);
}
}
/*
* now swap processes out if we are in low memory conditions
*/
if (!swap_pager_full && vm_swap_size &&
vm_pageout_req_swapout == 0) {
vm_pageout_req_swapout = 1;
vm_req_vmdaemon();
}
}
if ((cnt.v_inactive_count + cnt.v_free_count + cnt.v_cache_count) <
(cnt.v_inactive_target + cnt.v_free_min)) {
vm_req_vmdaemon();
}
/*
* 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(&cnt.v_free_count);
}
}
return force_wakeup;
}
/*
* vm_pageout is the high level pageout daemon.
*/
static void
vm_pageout()
{
(void) spl0();
/*
* Initialize some paging parameters.
*/
cnt.v_interrupt_free_min = 2;
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_interrupt_free_min;
cnt.v_free_reserved = cnt.v_pageout_free_min + 6;
cnt.v_free_target = 3 * cnt.v_free_min + cnt.v_free_reserved;
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) / 8;
cnt.v_inactive_target = 2*cnt.v_cache_min + 192;
} else {
cnt.v_cache_min = 0;
cnt.v_cache_max = 0;
cnt.v_inactive_target = cnt.v_free_count / 4;
}
/* XXX does not really belong here */
if (vm_page_max_wired == 0)
vm_page_max_wired = cnt.v_free_count / 3;
swap_pager_swap_init();
/*
* The pageout daemon is never done, so loop forever.
*/
while (TRUE) {
int s = splhigh();
if (!vm_pages_needed ||
((cnt.v_free_count >= cnt.v_free_reserved) &&
(cnt.v_free_count + cnt.v_cache_count >= cnt.v_free_min))) {
vm_pages_needed = 0;
tsleep(&vm_pages_needed, PVM, "psleep", 0);
}
vm_pages_needed = 0;
splx(s);
cnt.v_pdwakeups++;
vm_pager_sync();
vm_pageout_scan();
vm_pager_sync();
wakeup(&cnt.v_free_count);
wakeup(kmem_map);
}
}
static void
vm_daemon()
{
vm_object_t object;
struct proc *p;
while (TRUE) {
tsleep(&vm_daemon_needed, PUSER, "psleep", 0);
if (vm_pageout_req_swapout) {
swapout_procs();
vm_pageout_req_swapout = 0;
}
/*
* 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 * PAGE_SIZE;
if (limit >= 0 && size >= limit) {
overage = (size - limit) >> PAGE_SHIFT;
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:
object = vm_object_cached_list.tqh_first;
while (object) {
/*
* if there are no resident pages -- get rid of the object
*/
if (object->resident_page_count == 0) {
vm_object_reference(object);
pager_cache(object, FALSE);
goto restart;
}
object = object->cached_list.tqe_next;
}
}
}
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