Amount of physical memory that is desired be kept free for the rest of the system. Attempts to reserve memory for use as swap space by any process that causes the system's perception of available memory to fall below this value are rejected. Pages reserved in this manner can only be used for locked-down allocations by the kernel or by user-level processes.
The larger of 2 Mbytes and 1/8th of physical memory
1 to amount of physical memory
When processes are failing because of an inability to obtain swap space, yet the system has memory available.