Deadlock avoidance with a modified banker's algorithm

Abstract

There are three methods for handling deadlocks in resource allocation systems: deadlock prevention, deadlock avoidance and deadlock detection combined with recovery. Of these three methods deadlock avoidance is preferable in many cases but seldom used on account of its high cost. We present a simple modification of a known deadlock avoidance algorithm, the banker's algorithm, which has a running time Θ(mn ²) in a system consisting ofn processes andm different types of resources. Our modified algorithm gives an amortized worst case running time ofO(mn) under certain likely conditions and in that way it can be considered a competitive method for handling deadlocks. At worst, our algorithm is twice as fast as the banker's algorithm.