Extending Cache In A Multi-Processor Computer

Methods, apparatuses, and computer program products of extending cache in a multi-processor computer are provided. Embodiments include detecting, by a donor processor, nonuse of a donor processor's cache; broadcasting to one or more processors in the multi-processor computer, by the donor processor, a donor-ready message indicating the donor processor's cache is available for ownership transferment; receiving from a first requesting processor, by the donor processor, a first ownership-request message requesting ownership of the donor processor's cache by the first requesting processor; transmitting to the first requesting processor, by the donor processor, an ownership-grant message indicating an intention of the donor processor to transfer ownership of the donor processor's cache to the first requesting processor; and receiving from the first requesting processor, by the donor processor, an ownership-claim message indicating that the first requesting processor intends to claim ownership of the donor processor's cache.