For request blocks (RBs) and service request blocks (SRBs), alternate serialization methods are available. Usually, these alternate methods provide better performance than do WAIT and POST processing. To serialize an RB routine, use the SUSPEND, CALLDISP, and RESUME macros. The SUSPEND macro identifies the RB that is to be suspended until an expected event occurs. The CALLDISP macro enables a routine that has suspended the current RB to call the system to have other work dispatched. After issuing the CALLDISP macro, the RB routine is suspended. When the event occurs that the suspended RB is waiting for, use the RESUME macro to tell the system that the suspended RB is again eligible to execute.
Serializing an SRB is described in Serializing SRB processing.