COOTS 2001 Abstract
Distributed Garbage Collection for Wide Area Replicated Memory
Alfonso Sánchez, Luís Veiga, and Paulo Ferreira, INESC/IST, Portugal
It is well known that distributed systems pose serious difficulties
concerning memory management: when done manually, it leads to memory
leaks and dangling references causing applications to fail.
We address this problem by presenting a distributed garbage collection
(DGC) algorithm for distributed systems supporting replicated data
over wide area networks.
Current DGC algorithms are not well suited for such systems because
either (i) they do not consider the existence of replication, or (ii)
they impose severe constraints on scalability by requiring causal
delivery to be provided by the underlying communication layer.
Our algorithm solves these problems by (i) adapting classical
reference-counting DGC algorithms that were conceived for
non-replicated systems (e.g. indirect reference-counting, SSP chains,
etc.), and (ii) improving our previous algorithm for replicated
systems (i.e. Larchant).
The result is a DGC algorithm that, besides being correct in presence
of replicated data and independent of the protocol that maintains
such replicas coherent among processes, it does not require causal
delivery to be ensured by the underlying communications support.
In addition, it has minimal performance impact on applications.