In other words, vhand starts stealing pages when there are fewer than gpgslo free pages in the system. Once vhand starts stealing pages, it continues until there are gpgshi pages.
If, at boot time, gpgslo and gpgshi are 0, the system sets gpgshi to 8% of the number of pages of memory in the system, and sets gpgslo to one half of gpgshi.
This parameter is specified in /var/sysgen/mtune. For more information, see the kernel parameters gpgsmsk and gpgslo.
Range: 30 pages - 1/2 of memory