Final cache directory state indication

A computer program product comprising:

• one or more computer readable storage media and program instructions stored on the one or more computer readable storage media, the program instructions comprising instructions to:
• identify an initial designated authority (DA) member cache for a cache line, the initial DA member cache having a DA status;
• transfer the DA status from the initial DA member cache to a new DA member cache;
• receive an operation request;
• indicate that the initial DA member cache will be invalidated without allowing any other access to the cache line prior to invalidation;
• and
• allow the operation request to proceed as though the initial DA member cache has been invalidated prior to invalidation of the initial DA member cache.

A computer system comprising:

• one or more computer processors;
• one or more computer-readable storage media;
• and
• program instructions stored on the computer-readable storage media for execution by at least one of the one or more processors, the program instructions comprising instructions to:
• identify an initial designated authority (DA) member cache for a cache line, the initial DA member cache having a DA status;
• transfer the DA status from the initial DA member cache to a new DA member cache;
• receive an operation request;
• indicate that the initial DA member cache will be invalidated without allowing any other access to the cache line prior to invalidation;
• and
• allow the operation request to proceed as though the initial DA member cache has been invalidated prior to invalidation of the initial DA member cache.

A computer implemented method comprising:

• receiving a designated authority (DA) status transfer request from a first cache to a second cache of a corresponding cache line;
• receiving an indication that the first cache will invalidate a respective copy of the cache line without allowing any other access to the respective copy of the cache line prior to invalidation;
• responsive to the received indication, allowing the second cache to assume a DA status for the corresponding cache line prior to the first cache invalidating the respective copy of the cache line;
• and
• denying access to the respective copy of the cache line until invalidation by the first cache is complete.

A computer program product comprising:

• one or more computer readable storage media and program instructions stored on the one or more computer readable storage media, the program instructions comprising instructions to:
• receive a designated authority (DA) status transfer request from a first cache to a second cache of a corresponding cache line;
• receive an indication that the first cache will invalidate a respective copy of the cache line without allowing any other access to the respective copy of the cache line prior to invalidation;
• responsive to the received indication, allow the second cache to assume a DA status for the corresponding cache line prior to the first cache invalidating the respective copy of the cache line;
• and
• deny access to the respective copy of the cache line until invalidation by the first cache is complete.