An algorithm for k-mutual exclusion in decentralized systems

The distributed k-mutual exclusion problem or, simply the k-mutex problem, is the problem of allowing at most k processes to access their critical sections simultaneously. This might be the consequence where k identical copies of a resource are made available in the distributed system or that the resource by its nature can be accessed by at most k processes simultaneously. When a process enters it critical section such that there are l < k processes in their critical sections, there is no interference of the mutual exclusion condition. In this paper, we present an algorithm for the k-mutex problem. The algorithm is token based and k tokens are used. A node may enter the critical section only if it possesses a token. The algorithm has a worst case message complexity of O(n). Under heavy load the message requirement approaches 2 per critical section entry. The algorithm has been modified to enable fault tolerant capabilities. We have discussed node failure, message loss and link failure.