VMS Help SET, ENTRY, Qualifiers, /WSEXTENT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /WSEXTENT=n

    Defines, for the batch job, a working set extent, which is the
    maximum amount of physical memory that the job can use. The job
    uses the maximum amount of physical memory only when the system
    has excess free pages. If the queue on which the job executes has
    a nonzero working set extent, the smaller of the specified job
    and queue values is used. If the queue on which the job executes
    has a working set extent of zero, the smaller of the specified
    job value and the value established in the user authorization
    file (UAF) is used.

    Specify the value of n as a number of 512-byte pagelets on
    Alpha or 512-byte pages on VAX. Note that the operating system
    rounds up this value to the nearest CPU-specific page so that
    the actual amount of physical memory allowed may be larger than
    the specified amount on Alpha. If you specify zero or NONE, the
    specified queue or UAF value is used. Working set extent values
    must range between the numbers specified by the system parameters
    PQL_MWSEXTENT and WSMAX.