System using priority data of a host recall request to determine whether to release non-volatile storage with another host before processing further recall requests

A system for handling recall requests for data maintained in a non-volatile storage device from multiple host systems, comprising:

• a first host system capable of communicating with the non-volatile storage device;
• a second host system capable of communicating with the non-volatile storage device;
• a first memory location for storing data for access by a storage management program being executed on the second host system, comprising a first data structure defining a second host recall request for data stored in the non-volatile storage device, wherein the first data structure includes priority data indicating a priority of the second host recall request;
• a second memory location for storing data for access by a storage management program being executed on the first host system, comprising a second data structure defining a queue of recall requests for the non-volatile storage device;
• and
• a third memory location for storing data for access by storage management programs being executed on the first and second host systems comprising a third data structure indicating whether the non-volatile storage device is allocated to the first host system, wherein the second host system stores priority data in the third data structure indicating the priority of the second host recall request after determining that the non-volatile storage device is allocated to the first host system, wherein the second host system retries the second host recall request at a later time, and wherein the first host system uses the stored priority data in the third data structure to determine whether to release the non-volatile storage device before processing further recall requests indicated in the second data structure.

An article of manufacture for use in programming multiple host systems to process recall requests directed to a non-volatile storage device, the article of manufacture comprising at least one computer readable non-volatile storage device including at least one computer program embedded therein that causes the host systems to perform the steps of:

• allocating the non-volatile storage device to a first host system to process recall requests in a recall queue including a plurality of recall requests;
• initiating a second host recall request with a second host system for data from the non-volatile storage device;
• determining with the second host system whether the non-volatile storage device is allocated to the first host system;
• storing priority data in a data structure with the second host system indicating a priority of the second host recall request after determining that the non-volatile storage device is allocated to the first host system;
• retrying with the second host system the second host recall request at a later time;
• and
• using the stored priority data to determine whether to release the non-volatile storage device with the first host system before processing all the recall requests in the recall queue to make the non-volatile storage device available.

A plurality of memory locations for storing data for access by storage management programs being executed on multiple host systems capable of communicating with a non-volatile storage device, comprising:

• a first data structure defining a second host recall request initiated by a second host system for data stored in the non-volatile storage device, wherein the first data structure includes priority data indicating a priority of the second host recall request;
• a second data structure defining a queue of recall requests initiated by a first host system for the non-volatile storage device;
• and
• a third data structure indicating whether the non-volatile storage device is allocated to the first host system, wherein the second host system stores priority data in the third data structure indicating the priority of the second host recall request after determining that the non-volatile storage device is allocated to the first host system, wherein the second host system retries the second host recall request at a later time, and wherein the first host system processes the third data structure to determine whether to release the non-volatile storage device before processing further recall requests indicated in the second data structure.