From 53398ebe004ca1f6c195a7ec37bac59c678e9276 Mon Sep 17 00:00:00 2001 From: rstone Date: Thu, 17 Sep 2015 17:09:03 +0000 Subject: 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 --- sys/vm/vm_pageout.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'sys/vm') diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c index 998cd37..6a56fd7 100644 --- a/sys/vm/vm_pageout.c +++ b/sys/vm/vm_pageout.c @@ -93,6 +93,7 @@ __FBSDID("$FreeBSD$"); #include #include #include +#include #include #include #include @@ -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, int pass) * 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, int pass) * drained above. */ uma_reclaim(); - lowmem_ticks = ticks; + lowmem_uptime = time_uptime; } /* -- cgit v1.1