Moving this data in and out of memory as needed is done by kpiod and kswapd . Every second or so, kswapd wakes up to check out the memory situation, and if something out on the disk is needed in memory, or there is not enough free memory, kpiod is called in. There might also be a kapmd daemon running on your system if you have configured automatic power management into your kernel. The program update allows you to configure kflushd and kswapd . Try update -h for some information.
Swap space is turned on by swapon and off by swapoff .
I'm told that swapoff is handy for saving power on laptops. See what you can work out.