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freebsd/sys/vm/vm_pageout.c
John Dyson 4f4d35edf0 This commit is meant to solve a couple of VM system problems or 
performance issues.

	1) The pmap module has had too many inlines, and so the
	   object file is simply bigger than it needs to be.
	   Some common code is also merged into subroutines.
	2) Removal of some *evil* PHYS_TO_VM_PAGE macro calls.
	   Unfortunately, a few have needed to be added also.
	   The removal caused the need for more vm_page_lookups.
	   I added lookup hints to minimize the need for the
	   page table lookup operations.
	3) Removal of some bogus performance improvements, that
	   mostly made the code more complex (tracking individual
	   page table page updates unnecessarily).  Those improvements
	   actually hurt 386 processors perf (not that people who
	   worry about perf use 386 processors anymore :-)).
	4) Changed pv queue manipulations/structures to be TAILQ's.
	5) The pv queue code has had some performance problems since
	   day one.  Some significant scalability issues are resolved
	   by threading the pv entries from the pmap AND the physical
	   address instead of just the physical address.  This makes
	   certain pmap operations run much faster.  This does
	   not affect most micro-benchmarks, but should help loaded system
	   performance *significantly*.  DG helped and came up with most
	   of the solution for this one.
	6) Most if not all pmap bit operations follow the pattern:
		pmap_test_bit();
		pmap_clear_bit();
	   That made for twice the necessary pv list traversal.   The
	   pmap interface now supports only pmap_tc_bit type operations:
	   pmap_[test/clear]_modified, pmap_[test/clear]_referenced.
	   Additionally, the modified routine now takes a vm_page_t arg
	   instead of a phys address.  This eliminates a PHYS_TO_VM_PAGE
	   operation.
	7) Several rewrites of routines that contain redundant code to
	   use common routines, so that there is a greater likelihood of
	   keeping the cache footprint smaller.
1996-07-27 03:24:10 +00:00

1101 lines
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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 1.81 1996/07/08 02:25:53 dyson 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 <sys/vmmeter.h>
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_prot.h>
#include <vm/lock.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_pageout.h>
#include <vm/vm_kern.h>
#include <vm/vm_pager.h>
#include <vm/swap_pager.h>
#include <vm/vm_extern.h>
/*
* System initialization
*/
/* the kernel process "vm_pageout"*/
static void vm_pageout __P((void));
static int vm_pageout_clean __P((vm_page_t, int));
static int vm_pageout_scan __P((void));
static int vm_pageout_free_page_calc __P((vm_size_t count));
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)
#if !defined(NO_SWAPPING)
/* the kernel process "vm_daemon"*/
static void vm_daemon __P((void));
static 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)
#endif
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;
#if !defined(NO_SWAPPING)
static int vm_pageout_req_swapout; /* XXX */
static int vm_daemon_needed;
#endif
extern int nswiodone;
extern int vm_swap_size;
extern int vfs_update_wakeup;
int vm_pageout_algorithm_lru=0;
#if defined(NO_SWAPPING)
int vm_swapping_enabled=0;
#else
int vm_swapping_enabled=1;
#endif
SYSCTL_INT(_vm, VM_PAGEOUT_ALGORITHM, pageout_algorithm,
CTLFLAG_RW, &vm_pageout_algorithm_lru, 0, "");
#if defined(NO_SWAPPING)
SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swapping_enabled,
CTLFLAG_RD, &vm_swapping_enabled, 0, "");
#else
SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swapping_enabled,
CTLFLAG_RW, &vm_swapping_enabled, 0, "");
#endif
#define MAXLAUNDER (cnt.v_page_count > 1800 ? 32 : 16)
#define VM_PAGEOUT_PAGE_COUNT 16
int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT;
int vm_page_max_wired; /* XXX max # of wired pages system-wide */
#if !defined(NO_SWAPPING)
typedef void freeer_fcn_t __P((vm_map_t, vm_object_t, vm_pindex_t, int));
static void vm_pageout_map_deactivate_pages __P((vm_map_t, vm_pindex_t));
static freeer_fcn_t vm_pageout_object_deactivate_pages;
static void vm_req_vmdaemon __P((void));
#endif
/*
* 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!)
*/
static int
vm_pageout_clean(m, sync)
vm_page_t m;
int sync;
{
register vm_object_t object;
vm_page_t mc[2*vm_pageout_page_count];
int pageout_count;
int i, forward_okay, backward_okay, page_base;
vm_pindex_t pindex = m->pindex;
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_DEFAULT) &&
((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 (pindex != 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 ((pindex + i) > object->size) {
forward_okay = FALSE;
goto do_backward;
}
p = vm_page_lookup(object, pindex + i);
if (p) {
if ((p->queue == PQ_CACHE) || (p->flags & PG_BUSY) || p->busy) {
forward_okay = FALSE;
goto do_backward;
}
vm_page_test_dirty(p);
if ((p->dirty & p->valid) != 0 &&
((p->queue == PQ_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 ((pindex - i) == 0) {
backward_okay = FALSE;
}
p = vm_page_lookup(object, pindex - i);
if (p) {
if ((p->queue == PQ_CACHE) || (p->flags & PG_BUSY) || p->busy) {
backward_okay = FALSE;
continue;
}
vm_page_test_dirty(p);
if ((p->dirty & p->valid) != 0 &&
((p->queue == PQ_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;
}
}
}
for (i = page_base; i < (page_base + pageout_count); i++) {
mc[i]->flags |= PG_BUSY;
vm_page_protect(mc[i], VM_PROT_NONE);
}
return vm_pageout_flush(&mc[page_base], pageout_count, sync);
}
int
vm_pageout_flush(mc, count, sync)
vm_page_t *mc;
int count;
int sync;
{
register vm_object_t object;
int pageout_status[count];
int anyok = 0;
int i;
object = mc[0]->object;
object->paging_in_progress += count;
vm_pager_put_pages(object, mc, count,
((sync || (object == kernel_object)) ? TRUE : FALSE),
pageout_status);
for (i = 0; i < count; i++) {
vm_page_t mt = mc[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_tc_modified(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->queue == PQ_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);
PAGE_WAKEUP(mt);
}
}
return anyok;
}
#if !defined(NO_SWAPPING)
/*
* 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 void
vm_pageout_object_deactivate_pages(map, object, desired, map_remove_only)
vm_map_t map;
vm_object_t object;
vm_pindex_t desired;
int map_remove_only;
{
register vm_page_t p, next;
int rcount;
int remove_mode;
int s;
if (object->type == OBJT_DEVICE)
return;
while (object) {
if (vm_map_pmap(map)->pm_stats.resident_count <= desired)
return;
if (object->paging_in_progress)
return;
remove_mode = map_remove_only;
if (object->shadow_count > 1)
remove_mode = 1;
/*
* scan the objects entire memory queue
*/
rcount = object->resident_page_count;
p = TAILQ_FIRST(&object->memq);
while (p && (rcount-- > 0)) {
int refcount;
if (vm_map_pmap(map)->pm_stats.resident_count <= desired)
return;
next = TAILQ_NEXT(p, listq);
cnt.v_pdpages++;
if (p->wire_count != 0 ||
p->hold_count != 0 ||
p->busy != 0 ||
(p->flags & PG_BUSY) ||
!pmap_page_exists(vm_map_pmap(map), VM_PAGE_TO_PHYS(p))) {
p = next;
continue;
}
refcount = pmap_tc_referenced(VM_PAGE_TO_PHYS(p));
if (refcount) {
p->flags |= PG_REFERENCED;
} else if (p->flags & PG_REFERENCED) {
refcount = 1;
}
if ((p->queue != PQ_ACTIVE) &&
(p->flags & PG_REFERENCED)) {
vm_page_activate(p);
p->act_count += refcount;
p->flags &= ~PG_REFERENCED;
} else if (p->queue == PQ_ACTIVE) {
if ((p->flags & PG_REFERENCED) == 0) {
p->act_count -= min(p->act_count, ACT_DECLINE);
if (!remove_mode && (vm_pageout_algorithm_lru || (p->act_count == 0))) {
vm_page_protect(p, VM_PROT_NONE);
vm_page_deactivate(p);
} else {
s = splvm();
TAILQ_REMOVE(&vm_page_queue_active, p, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq);
splx(s);
}
} else {
p->flags &= ~PG_REFERENCED;
if (p->act_count < (ACT_MAX - ACT_ADVANCE))
p->act_count += ACT_ADVANCE;
s = splvm();
TAILQ_REMOVE(&vm_page_queue_active, p, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq);
splx(s);
}
} else if (p->queue == PQ_INACTIVE) {
vm_page_protect(p, VM_PROT_NONE);
}
p = next;
}
object = object->backing_object;
}
return;
}
/*
* 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, desired)
vm_map_t map;
vm_pindex_t desired;
{
vm_map_entry_t tmpe;
vm_object_t obj, bigobj;
vm_map_reference(map);
if (!lock_try_write(&map->lock)) {
vm_map_deallocate(map);
return;
}
bigobj = NULL;
/*
* first, search out the biggest object, and try to free pages from
* that.
*/
tmpe = map->header.next;
while (tmpe != &map->header) {
if ((tmpe->is_sub_map == 0) && (tmpe->is_a_map == 0)) {
obj = tmpe->object.vm_object;
if ((obj != NULL) && (obj->shadow_count <= 1) &&
((bigobj == NULL) ||
(bigobj->resident_page_count < obj->resident_page_count))) {
bigobj = obj;
}
}
tmpe = tmpe->next;
}
if (bigobj)
vm_pageout_object_deactivate_pages(map, bigobj, desired, 0);
/*
* Next, hunt around for other pages to deactivate. We actually
* do this search sort of wrong -- .text first is not the best idea.
*/
tmpe = map->header.next;
while (tmpe != &map->header) {
if (vm_map_pmap(map)->pm_stats.resident_count <= desired)
break;
if ((tmpe->is_sub_map == 0) && (tmpe->is_a_map == 0)) {
obj = tmpe->object.vm_object;
if (obj)
vm_pageout_object_deactivate_pages(map, obj, desired, 0);
}
tmpe = tmpe->next;
};
/*
* Remove all mappings if a process is swapped out, this will free page
* table pages.
*/
if (desired == 0)
pmap_remove(vm_map_pmap(map),
VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS);
vm_map_unlock(map);
vm_map_deallocate(map);
return;
}
#endif
/*
* vm_pageout_scan does the dirty work for the pageout daemon.
*/
static int
vm_pageout_scan()
{
vm_page_t m, next;
int page_shortage, addl_page_shortage, maxscan, maxlaunder, pcount;
int pages_freed;
struct proc *p, *bigproc;
vm_offset_t size, bigsize;
vm_object_t object;
int force_wakeup = 0;
int vnodes_skipped = 0;
int s;
/*
* 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.
*/
pages_freed = 0;
addl_page_shortage = 0;
maxlaunder = (cnt.v_inactive_target > MAXLAUNDER) ?
MAXLAUNDER : cnt.v_inactive_target;
maxscan = cnt.v_inactive_count;
for( m = TAILQ_FIRST(&vm_page_queue_inactive);
(m != NULL) && (maxscan-- > 0) &&
((cnt.v_cache_count + cnt.v_free_count) <
(cnt.v_cache_min + cnt.v_free_target));
m = next) {
cnt.v_pdpages++;
if (m->queue != PQ_INACTIVE) {
break;
}
next = TAILQ_NEXT(m, pageq);
if (m->hold_count) {
s = splvm();
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
splx(s);
addl_page_shortage++;
continue;
}
/*
* Dont mess with busy pages, keep in the front of the
* queue, most likely are being paged out.
*/
if (m->busy || (m->flags & PG_BUSY)) {
addl_page_shortage++;
continue;
}
if (m->valid != 0) {
if (m->object->ref_count == 0) {
m->flags &= ~PG_REFERENCED;
pmap_tc_referenced(VM_PAGE_TO_PHYS(m));
} else if (((m->flags & PG_REFERENCED) == 0) &&
pmap_tc_referenced(VM_PAGE_TO_PHYS(m))) {
vm_page_activate(m);
continue;
}
if ((m->flags & PG_REFERENCED) != 0) {
m->flags &= ~PG_REFERENCED;
pmap_tc_referenced(VM_PAGE_TO_PHYS(m));
vm_page_activate(m);
continue;
}
if (m->dirty == 0) {
vm_page_test_dirty(m);
} else if (m->dirty != 0) {
m->dirty = VM_PAGE_BITS_ALL;
}
}
if (m->valid == 0) {
vm_page_protect(m, VM_PROT_NONE);
vm_page_free(m);
++cnt.v_dfree;
++pages_freed;
} else if (m->dirty == 0) {
vm_page_cache(m);
++pages_freed;
} else if (maxlaunder > 0) {
int written;
struct vnode *vp = NULL;
object = m->object;
if (object->flags & OBJ_DEAD) {
s = splvm();
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
splx(s);
continue;
}
if (object->type == OBJT_VNODE) {
vp = object->handle;
if (VOP_ISLOCKED(vp) || vget(vp, 1)) {
if ((m->queue == PQ_INACTIVE) &&
(m->hold_count == 0) &&
(m->busy == 0) &&
(m->flags & PG_BUSY) == 0) {
s = splvm();
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
splx(s);
}
if (object->flags & OBJ_MIGHTBEDIRTY)
++vnodes_skipped;
continue;
}
/*
* The page might have been moved to another queue
* during potential blocking in vget() above.
*/
if (m->queue != PQ_INACTIVE) {
if (object->flags & OBJ_MIGHTBEDIRTY)
++vnodes_skipped;
vput(vp);
continue;
}
/*
* The page may have been busied during the blocking in
* vput(); We don't move the page back onto the end of
* the queue so that statistics are more correct if we don't.
*/
if (m->busy || (m->flags & PG_BUSY)) {
vput(vp);
continue;
}
/*
* If the page has become held, then skip it
*/
if (m->hold_count) {
s = splvm();
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
splx(s);
if (object->flags & OBJ_MIGHTBEDIRTY)
++vnodes_skipped;
vput(vp);
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);
maxlaunder -= written;
}
}
/*
* 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_cache_min) -
(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;
}
}
if (addl_page_shortage) {
if (page_shortage < 0)
page_shortage = 0;
page_shortage += addl_page_shortage;
}
pcount = cnt.v_active_count;
m = TAILQ_FIRST(&vm_page_queue_active);
while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) {
int refcount;
if (m->queue != PQ_ACTIVE) {
break;
}
next = TAILQ_NEXT(m, pageq);
/*
* Don't deactivate pages that are busy.
*/
if ((m->busy != 0) ||
(m->flags & PG_BUSY) ||
(m->hold_count != 0)) {
s = splvm();
TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
splx(s);
m = next;
continue;
}
/*
* The count for pagedaemon pages is done after checking the
* page for eligbility...
*/
cnt.v_pdpages++;
refcount = 0;
if (m->object->ref_count != 0) {
if (m->flags & PG_REFERENCED) {
refcount += 1;
}
refcount += pmap_tc_referenced(VM_PAGE_TO_PHYS(m));
if (refcount) {
m->act_count += ACT_ADVANCE + refcount;
if (m->act_count > ACT_MAX)
m->act_count = ACT_MAX;
}
}
m->flags &= ~PG_REFERENCED;
if (refcount && (m->object->ref_count != 0)) {
s = splvm();
TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
splx(s);
} else {
m->act_count -= min(m->act_count, ACT_DECLINE);
if (vm_pageout_algorithm_lru ||
(m->object->ref_count == 0) || (m->act_count == 0)) {
--page_shortage;
vm_page_protect(m, VM_PROT_NONE);
if ((m->dirty == 0) &&
(m->object->ref_count == 0)) {
vm_page_cache(m);
} else {
vm_page_deactivate(m);
}
} else {
s = splvm();
TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
splx(s);
}
}
m = next;
}
s = splvm();
/*
* 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 = TAILQ_FIRST(&vm_page_queue_cache);
if (!m)
break;
vm_page_free(m);
cnt.v_dfree++;
}
splx(s);
/*
* 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 + cnt.v_cache_min) ) {
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);
}
}
#if !defined(NO_SWAPPING)
if (vm_swapping_enabled &&
(cnt.v_free_count + cnt.v_cache_count < cnt.v_free_target)) {
vm_req_vmdaemon();
vm_pageout_req_swapout = 1;
}
#endif
}
/*
* 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 = allproc.lh_first; p != 0; p = p->p_list.le_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) {
killproc(bigproc, "out of swap space");
bigproc->p_estcpu = 0;
bigproc->p_nice = PRIO_MIN;
resetpriority(bigproc);
wakeup(&cnt.v_free_count);
}
}
return force_wakeup;
}
static int
vm_pageout_free_page_calc(count)
vm_size_t count;
{
if (count < cnt.v_page_count)
return 0;
/*
* free_reserved needs to include enough for the largest swap pager
* structures plus enough for any pv_entry structs when paging.
*/
if (cnt.v_page_count > 1024)
cnt.v_free_min = 4 + (cnt.v_page_count - 1024) / 200;
else
cnt.v_free_min = 4;
cnt.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE +
cnt.v_interrupt_free_min;
cnt.v_free_reserved = vm_pageout_page_count +
cnt.v_pageout_free_min + (count / 768);
cnt.v_free_min += cnt.v_free_reserved;
return 1;
}
#ifdef unused
int
vm_pageout_free_pages(object, add)
vm_object_t object;
int add;
{
return vm_pageout_free_page_calc(object->size);
}
#endif
/*
* 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 < 2000)
vm_pageout_page_count = 8;
vm_pageout_free_page_calc(cnt.v_page_count);
/*
* free_reserved needs to include enough for the largest swap pager
* structures plus enough for any pv_entry structs when paging.
*/
cnt.v_free_target = 3 * cnt.v_free_min + cnt.v_free_reserved;
if (cnt.v_free_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 inactive_target;
int s = splvm();
if (!vm_pages_needed ||
((cnt.v_free_count + cnt.v_cache_count) > cnt.v_free_min)) {
vm_pages_needed = 0;
tsleep(&vm_pages_needed, PVM, "psleep", 0);
} else if (!vm_pages_needed) {
tsleep(&vm_pages_needed, PVM, "psleep", hz/10);
}
inactive_target =
(cnt.v_page_count - cnt.v_wire_count) / 4;
if (inactive_target < 2*cnt.v_free_min)
inactive_target = 2*cnt.v_free_min;
cnt.v_inactive_target = inactive_target;
if (vm_pages_needed)
cnt.v_pdwakeups++;
vm_pages_needed = 0;
splx(s);
vm_pager_sync();
vm_pageout_scan();
vm_pager_sync();
wakeup(&cnt.v_free_count);
}
}
#if !defined(NO_SWAPPING)
static void
vm_req_vmdaemon()
{
static int lastrun = 0;
if ((ticks > (lastrun + hz)) || (ticks < lastrun)) {
wakeup(&vm_daemon_needed);
lastrun = ticks;
}
}
static void
vm_daemon()
{
vm_object_t object;
struct proc *p;
(void) spl0();
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 = allproc.lh_first; p != 0; p = p->p_list.le_next) {
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) {
vm_pageout_map_deactivate_pages(&p->p_vmspace->vm_map,
(vm_pindex_t)(limit >> PAGE_SHIFT) );
}
}
/*
* we remove cached objects that have no RSS...
*/
restart:
object = TAILQ_FIRST(&vm_object_cached_list);
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 = TAILQ_NEXT(object, cached_list);
}
}
}
#endif
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