Granting exclusive cache access using locality cache coherency state

A computer program product for managing exclusive access to cache lines of a cache of a computing environment, said computer program product comprising:

• a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:
• requesting, by a node of the computing environment, exclusive access to a selected cache line of the cache, the computing environment including a plurality of regions of nodes and the requesting comprising sending a request for exclusive access to at least multiple regions of nodes of the plurality of regions of nodes, wherein one region of nodes of the plurality of regions of nodes includes a plurality of nodes, the plurality of nodes comprising the node requesting exclusive access and another node of the computing environment, wherein the node requesting exclusive access and the another node are local to one another as defined by a predetermined criteria, and wherein at least one node of the node requesting exclusive access and the another node includes a plurality of processors;
• checking, by the node requesting exclusive access, a locality cache coherency state of the another node of the one region of nodes, the locality cache coherency state being on a per cache line basis to indicate whether a copy of the selected cache line is maintained outside of the plurality of nodes of the one region of nodes, the locality cache coherency state, based on being set to a defined value, indicating that no node outside of the one region of nodes has a copy of the selected cache line and that at least one node within the one region of nodes has access to the selected cache line;
• and
• determining, based on the locality cache coherency state indicating that the another node has access to the selected cache line, that the node requesting exclusive access is to be granted exclusive access to the selected cache line, the determining being independent of transmission of information relating to the selected cache line from one or more other nodes of one or more other regions of nodes of the plurality of regions of nodes, and wherein, in response to the locality cache coherency state indicating that the another node has access to the selected cache line, the determining ignores information, other than provided by the locality cache coherency state of the another node, of whether nodes outside of the one region of nodes have copies of the selected cache line.