Patent ID: 8543769

Claim:
A method, in a data processing system, for fine grained cache allocation of a shared cache, the method comprising: receiving, by a cache controller, a tag portion from an application, within a plurality of applications, to allocate a group of cache lines in a shared cache to the application, wherein each cache line within the shared cache has a tag having a most significant bit portion and a least significant hit portion, wherein the shared cache is shared between the plurality of applications, wherein the most significant bit portion of the tag comprises a group tag for each group of cache lines, wherein the least significant bit portion of the tag comprises a private tag for each respective cache line, wherein only cache lines with the most significant bit portion of the tag can be cached in the group of cache lines; allocating the group of cache lines to the application by setting the most significant hit tag portion to the tag portion horn the application for the group of cache lines in a tag array of the shared cache; responsive to an attempt to overwrite a given cache line within the group of cache lines, determining whether the given cache line is locked to the application based on the most significant bit tag portion of the given cache line; and overwriting, by the cache controller, the given cache line if the cache line is not locked, wherein overwriting the given cache line comprises overwriting a most significant bit portion of a tag of the given cache line.