Avoiding unbounded priority inversion by integrating task inheritance and classification into preemption threshold scheduling

This paper considers the uncontrolled priority inversion problem occurs when a higher-priority thread is suspended because a lower-priority thread has a needed resource. A new strategy is presented to prevent uncontrolled priority inversion which integrates the priority inheritance protocol, the priority ceiling protocol, and the task classification based upon the priority of their subtasks relative to the task into preemption threshold scheduling. The new strategy provides schedulability improvement and reduces the excessive preemption overhead