Concurrent garbage collection on stock hardware

Abstract

We have demonstrated a practical design for memory management in a concurrent system running on stack hardware. Under our modification of Brooks' forwarding pointers, the only runtime costs, owing to storage reclamation, incurred by user processes are an extra level of indirection when accessing object contents and the need to scavenge when updating mutable objects. Therefore, we believe that our system can successfully off-load much of the cost of memory management to, otherwise unused, dead-time. Beyond Pegasus, this work has application to any system based on lightweight processes and heap allocation. We believe the ease with which the memory management system was implemented is a testimony to the soundness of Pegasus as a foundation for building programming environments.