Concurrent patch to logical partition manager of a logically partitioned system

摘要

A method of replacing a current version of a program module with a replacement version of the module concurrently with the execution of the program on a computer system. While execution of the program is suspended, each address reference in the program to an entry point within the current version of the module is replaced with an address reference to the corresponding entry point within the replacement version of the module. After the address references have been replaced and before execution is resumed, a patch initialization routine is invoked to perform initialization functions such as storage allocation, table initialization and feature detection that are performed before execution of the concurrently applied patch. Execution of the program is resumed when each address reference to the current module has been replaced with one to the replacement module and the patch initialization routine has been performed. A bit vector is used to ensure that each initialization function is performed only once per instantiation of the program being patched. An available storage value indicates the amount of initially allocated storage remaining available after performing an initialization function involving storage allocation.