Library /sys$common/syshlp/uafhelp.hlb ADD, Qualifiers, /WSEXTENT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /WSEXTENT=value

    Specifies the working set maximum. This represents the maximum
    amount of physical memory allowed to the process. The system
    provides memory to a process beyond its working set quota only
    when it has excess free pages. The additional memory is recalled
    by the system if needed.

    The value is an integer equal to or greater than WSQUOTA. By
    default, the value is 1024 pages on VAX systems and 16384
    pagelets on Alpha systems. The value cannot be greater than
    WSMAX. This quota value replaces smaller values of PQL_MWSEXTENT.