A stack-based resource allocation policy for realtime processes

The Stack Resource Policy (SRP) is a resource allocation policy which permits processes with different priorities to share a single runtime stack. It is a refinement of the Priority Ceiling Protocol (PCP) of Sha, Rajkumar and Lehoczky, which strictly bounds priority inversion and permits simple schedulability tests. With or without stack sharing, the SRP offers im-provements over the PCP, by: (1) unifying the treatment of stack, reader-writer, and multiunit resources, and bi-nary semaphores; (2) applying directly to some dynamic scheduling policies, including EDF, as well as to static priority policies; (3) with EDF scheduling, supporting a stronger schedulability test; (4) reducing the maximum number of context switches for a job execution request by a factor of two. It is at least as good as the PCP in reducing maximum priority inversion.