Author: rstone
Date: Thu Sep 17 17:09:03 2015
New Revision: 287922
URL: https://svnweb.freebsd.org/changeset/base/287922
Log:
MFC r286970:
Prevent ticks rollover from preventing vm_lowmem event
Currently vm_pageout_scan() uses a ticks-based scheme to rate-limit
the number of times that the vm_lowmem event will happen. However
if no events happen for long enough for ticks to roll over, this
leaves us in a long window in which vm_lowmem events will not
happen.
Replace the use of ticks with time_t to prevent rollover from ever
being an issue.
Reviewed by: ian
MFC after: 3 weeks
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D3439
Modified:
stable/10/sys/vm/vm_pageout.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/vm/vm_pageout.c
==============================================================================
--- stable/10/sys/vm/vm_pageout.c Thu Sep 17 17:00:36 2015
(r287921)
+++ stable/10/sys/vm/vm_pageout.c Thu Sep 17 17:09:03 2015
(r287922)
@@ -93,6 +93,7 @@ __FBSDID("$FreeBSD$");
#include <sys/sdt.h>
#include <sys/signalvar.h>
#include <sys/smp.h>
+#include <sys/time.h>
#include <sys/vnode.h>
#include <sys/vmmeter.h>
#include <sys/rwlock.h>
@@ -170,7 +171,7 @@ static int vm_pageout_update_period;
static int defer_swap_pageouts;
static int disable_swap_pageouts;
static int lowmem_period = 10;
-static int lowmem_ticks;
+static time_t lowmem_uptime;
#if defined(NO_SWAPPING)
static int vm_swap_enabled = 0;
@@ -932,7 +933,7 @@ vm_pageout_scan(struct vm_domain *vmd, i
* some. We rate limit to avoid thrashing.
*/
if (vmd == &vm_dom[0] && pass > 0 &&
- (ticks - lowmem_ticks) / hz >= lowmem_period) {
+ (time_uptime - lowmem_uptime) >= lowmem_period) {
/*
* Decrease registered cache sizes.
*/
@@ -943,7 +944,7 @@ vm_pageout_scan(struct vm_domain *vmd, i
* drained above.
*/
uma_reclaim();
- lowmem_ticks = ticks;
+ lowmem_uptime = time_uptime;
}
/*
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