Abstract

We present a 'fine-grained' solution to the mutual exclusion problem. A program is finegrained if it uses only single-reader, single-writer boolean variables and if each of its atomic operations has at most one occurrence of at most one shared variable. In contrast to other fine-grained solutions that have appeared in the literature, processes in our solution do not busy-wait, but wait on one another only by executing await statements. Such statements can be implemented in practice either by means of context switching or by means of 'local' spinning. We show that our algorithm is correct even if shared variables are accessed nonatomically. Keywords: Busy-waiting, mutual exclusion, nonatomic operations, shared data, synchronization primitives.

Citations