Patent ID: 7415556

Claim:
An exclusion controller which allows an information processing unit to acquire a contended resource to the exclusion of other information processing units, the exclusion controller comprising: a storage area including i) a prioritized information processing unit information storage area for storing information for identifying a prioritized information processing unit that is to execute writes for acquiring a contended resource by using normal write instructions; ii) a prioritized exclusion right information storage area for storing information indicating whether the prioritized information processing unit is trying to acquire the contended resource; and iii) a non-prioritized exclusion right information storage area for storing non-prioritized exclusion right information that indicates whether a non-prioritized exclusion right has been acquired by a non-prioritized information processing unit, a plurality of non-prioritized information processing units mutually exclusively acquiring a non-prioritized exclusion right by a first process using the information in the non-prioritized exclusion right information storage area to determine that the non-prioritized exclusion right information has not yet been stored, the non-prioritized exclusion right indicating a candidate for acquiring the contended resource, the first process executing writes by using compare-and-swap instructions; and a prioritized information processing unit identified by the prioritized information processing unit information storage area acquiring the contended resource by a second process to the exclusion of the non-prioritized information processing unit having acquired the non-prioritized exclusion right, the exclusion being determined from the non-prioritized exclusion right information storage area, updating the information in the prioritized exclusion right information storage area to indicate that the prioritized information processing unit is trying to acquire the contended resource, the second process executing writes by using normal write instructions.