On HPUX it is impossible for a userspace process to query the maximum allocatable amount of memory for a single process. This is actually not an issue with this module, since it will start using VM files when system memory is exhausted.
Swapping mapped files proves to be extremely unefficient on HPUX, but this probably also depends on the kind of hard disks available on the machine. Only benchmarking can give a reasonable estimate for HP performances.