When to use a reusable ASID

Consider the following situations when determining when to use a reusable ASID:
  • If you have an address space that becomes nonreusable when it terminates, as identified by the message IEF352I ADDRESS SPACE UNAVAILABLE at termination, consider using a reusable ASID with it.
  • If you have an address space that does not become nonreusable when it terminates, do not use a reusable ASID with it.
To use a reusable ASID, specify REUSASID=YES on the START command for the address space or specify ATTR=(REUSASID) on the ASCRE.
Note: If there is a request for a reusable ASID but there are no available ASIDs that were previously used as reusable ASIDs, z/OS® takes an ASID from the pool of available ordinary ASIDs to satisfy the request.
If any 0D3 abends then result from the use of a reusable ASID, investigate and resolve them.
Attention: As soon as an ASID is used to satisfy a request for a reusable ASID, it must always serve as a reusable ASID; you cannot then use it for a START without REUSASID=YES or an ASCRE without ATTR=(REUSASID). Unnecessary use of REUSASID=YES or ATTR=(REUSASID) can reduce the number of ordinary ASIDs that are available for satisfying ordinary address space requests.