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Fix a couple of problems in the pageout_scan routine. First, there is

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a condition when blocking can occur, and the daemon did not check properly
for a page remaining on the expected queue.  Additionally, the inactive
target was being set much too large for small memory machines.  It is now
being calculated based upon the amount of user memory available on every
pageout daemon run.  Another problem was that if memory was very low, the
pageout daemon could fail repeatedly to traverse the inactive queue.
This commit is contained in:
John Dyson 1996-05-26 07:52:09 +00:00
parent 0ed4376231
commit 85a376eb93
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=15905
1 changed files with 17 additions and 3 deletions
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20
sys/vm/vm_pageout.c
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@ -65,7 +65,7 @@
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $Id: vm_pageout.c,v 1.71 1996/05/18 03:38:00 dyson Exp $
* $Id: vm_pageout.c,v 1.72 1996/05/24 05:19:15 dyson Exp $
*/
/*
@ -540,6 +540,7 @@ vm_pageout_scan()
* them.
*/
rescan0:
maxlaunder = (cnt.v_inactive_target > MAXLAUNDER) ?
MAXLAUNDER : cnt.v_inactive_target;
@ -554,12 +555,10 @@ vm_pageout_scan()
cnt.v_pdpages++;
next = TAILQ_NEXT(m, pageq);
#if defined(VM_DIAGNOSE)
if (m->queue != PQ_INACTIVE) {
printf("vm_pageout_scan: page not inactive?\n");
break;
}
#endif
/*
* Dont mess with busy pages, keep in the front of the
@ -611,6 +610,8 @@ vm_pageout_scan()
object = m->object;
if (object->flags & OBJ_DEAD) {
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
m = next;
continue;
}
@ -618,8 +619,15 @@ vm_pageout_scan()
if (object->type == OBJT_VNODE) {
vp = object->handle;
if (VOP_ISLOCKED(vp) || vget(vp, 1)) {
if (m->queue == PQ_INACTIVE) {
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
}
if (object->flags & OBJ_MIGHTBEDIRTY)
++vnodes_skipped;
if (next->queue != PQ_INACTIVE) {
goto rescan0;
}
m = next;
continue;
}
@ -852,6 +860,7 @@ vm_pageout()
* 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_free_reserved) &&
@ -867,6 +876,11 @@ vm_pageout()
splx(s);
vm_pager_sync();
vm_pageout_scan();
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;
vm_pager_sync();
wakeup(&cnt.v_free_count);
}