Garbage Collection and DSM Consistency

This paper presents the design of a copying garbage collector for persistent distributed shared objects in a loosely coupled network with weakly consistent distributed shared memory (DSM). The main goal of the design for this garbage collector is to minimize the communication overhead due to collection between nodes of the system, and to avoid any interference with the DSM memory consistency protocol. Our design is based ont eh observation that, in a weakly consistent DSM system, the memory consistency requirements of the garbage collector are less strict than those of the applications. Thus, the garbage collector reclaims objects independently of other copies of the same objects without interfering with the DSM consistency protocol. Furthermore, our design does not require reliable communication support, and is capable of reclaiming distributed cycles of dead objects.