From 00c2438241750769b9da9c896e4f99c662035b7c Mon Sep 17 00:00:00 2001 From: Kirk McKusick Date: Fri, 8 Mar 1985 02:38:54 -0800 Subject: [PATCH] Add a second hand to the clock algorithm. The front hand clears the reference bit, the back hand frees pages that are still unreferenced. SCCS-vsn: sys/vax/include/vmparam.h 6.4 --- usr/src/sys/vax/include/vmparam.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/usr/src/sys/vax/include/vmparam.h b/usr/src/sys/vax/include/vmparam.h index 139f90406b..a644605cd7 100644 --- a/usr/src/sys/vax/include/vmparam.h +++ b/usr/src/sys/vax/include/vmparam.h @@ -1,4 +1,4 @@ -/* vmparam.h 6.3 85/03/07 */ +/* vmparam.h 6.4 85/03/07 */ /* * Machine dependent constants for VAX @@ -109,6 +109,20 @@ #define MINFREE (64 * 1024) #define MINFREEFRACT 2 +/* + * There are two clock hands, initially separated by HANDSPREAD bytes + * (but at most all of user memory). The amount of time to reclaim + * a page once the pageout process examines it increases with this + * distance and decreases as the scan rate rises. + */ +#define HANDSPREAD (2 * 1024 * 1024) + +/* + * The number of times per second to recompute the desired paging rate + * and poke the pagedaemon. + */ +#define RATETOSCHEDPAGING 4 + /* * Believed threshold (in megabytes) for which interleaved * swapping area is desirable. -- 2.20.1