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Support applications that need to resist or deny use of swap space.

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sysctl -w vm.defer_swap_pageouts=1
	Causes the system to resist the use of swap space.  In low memory
	conditions, performance will decrease.
sysctl -w vm.disable_swap_pageouts=1
	Causes the system to mostly disable the use of swap space.  In
	low memory conditions, the system will likely start killing
	processes.
This commit is contained in:
John Dyson 1997-12-04 19:00:56 +00:00
parent 4bfaee9023
commit 12ac6a1dbb
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=31542
1 changed files with 26 additions and 2 deletions
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28
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 1.99 1997/10/06 02:48:16 dyson Exp $
* $Id: vm_pageout.c,v 1.100 1997/10/25 02:41:56 dyson Exp $
*/
/*
@ -141,6 +141,8 @@ extern int vfs_update_wakeup;
int vm_pageout_stats_max=0, vm_pageout_stats_interval = 0;
int vm_pageout_full_stats_interval = 0;
int vm_pageout_stats_free_max=0, vm_pageout_algorithm_lru=0;
int defer_swap_pageouts=0;
int disable_swap_pageouts=0;
#if defined(NO_SWAPPING)
int vm_swapping_enabled=0;
#else
@ -170,6 +172,12 @@ SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swapping_enabled,
CTLFLAG_RW, &vm_swapping_enabled, 0, "");
#endif
SYSCTL_INT(_vm, OID_AUTO, defer_swap_pageouts,
CTLFLAG_RW, &defer_swap_pageouts, 0, "");
SYSCTL_INT(_vm, OID_AUTO, disable_swap_pageouts,
CTLFLAG_RW, &disable_swap_pageouts, 0, "");
#define MAXLAUNDER (cnt.v_page_count > 1800 ? 32 : 16)
#define VM_PAGEOUT_PAGE_COUNT 16
@ -716,6 +724,7 @@ vm_pageout_scan()
*/
} else if (maxlaunder > 0) {
int written;
int swap_pageouts_ok;
struct vnode *vp = NULL;
object = m->object;
@ -732,6 +741,22 @@ vm_pageout_scan()
continue;
}
if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) {
swap_pageouts_ok = 1;
} else {
swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts);
swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts &&
(cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min);
}
if (!swap_pageouts_ok) {
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) ||
@ -793,7 +818,6 @@ vm_pageout_scan()
* start the cleaning operation.
*/
written = vm_pageout_clean(m, 0);
if (vp)
vput(vp);