Memory Management Based on Method Invocation in RTSJ

Abstract

In this paper, we present a memory management model for the Ravenscar-Java profile. Because of the complexity and run-time overheads in verifying the proper use of the RTSJ’s scoped memory, it is unfavourable in the area of high integrity systems where any unpredictability must be cast out. Our approach maps one anonymous memory area to a user-specifiable method by means of our Java 1.5 annotation types. This straightforward model eliminates single parent rule checks and simplifies other run-time checks that are the main cause of unpredictability and overheads. In fact, it also makes the programmer’s job easier since he/she does not have to worry about creating and maintaining memory areas. All the annotated methods will be automatically converted by a transformer into an RTSJ/Ravenscar-Java compliant version. The semantics of the RTSJ remains the same, meaning that any program in our model when transformed is also a legal RTSJ program. Our key contribution is the definition of a predictable memory model and guidelines that will reduce/eliminate run-time overheads. A bonus to this is a less complicated programming model.