The Oracle Solaris OS uses a two-handed clock algorithm to look for pages that are candidates for reclaiming when memory is low. The first hand of the clock walks through memory marking pages as unused. The second hand walks through memory some distance after the first hand, checking to see if the page is still marked as unused. If so, the page is subject to being reclaimed. The distance between the first hand and the second hand is handspreadpages.
1 to maximum number of physical memory pages on the system
Yes. This parameter requires that the kernel reset_hands parameter also be set to a non-zero value. Once the new value of handspreadpages has been recognized, reset_hands is set to zero.
The value is set to the lesser of either the amount of physical memory and the handspreadpages value.
When you want to increase the amount of time that pages are potentially resident before being reclaimed. Increasing this value increases the separation between the hands, and therefore, the amount of time before a page can be reclaimed.