Date: Thu, 17 Sep 2015 17:09:04 +0000 (UTC) From: Ryan Stone <rstone@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r287922 - stable/10/sys/vm Message-ID: <201509171709.t8HH94Im091953@repo.freebsd.org>
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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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