Malloc disclaim
Malloc Disclaim is an optional extension of the malloc subsystem, providing the user with a means to enable the automatic disclaiming of memory returned by the free subroutine.
This is useful in instances where a process has a high paging-space usage, but is not actually using the memory.
Malloc Disclaim is not enabled by default. It can be enabled and
configured prior to process startup through the MALLOCOPTIONS environment
variable, as follows:
MALLOCOPTIONS=disclaim