Deadlock in OS

 

Introduction of Deadlock in Operating System

 

A process in operating system uses resources in the following way. 

1. Requests a resource 
2. Use the resource 
3. Releases the resource 

A deadlock is a situation where a set of processes are blocked because each process is holding a resource and waiting for another resource acquired by some other process. 

Recovery from Deadlock

1. Manual Intervention:

When a deadlock is detected, one option is to inform the operator and let them handle the situation manually. While this approach allows for human judgment and decision-making, it can be time-consuming and may not be feasible in large-scale systems.

2. Automatic Recovery:

An alternative approach is to enable the system to recover from deadlock automatically. This method involves breaking the deadlock cycle by either aborting processes or preempting resources. Let’s delve into these strategies in more detail.

Recovery from Deadlock: Process Termination:

1. Abort all deadlocked processes:

This approach breaks the deadlock cycle, but it comes at a significant cost. The processes that were aborted may have executed for a considerable amount of time, resulting in the loss of partial computations. These computations may need to be recomputed later.

2. Abort one process at a time:

Instead of aborting all deadlocked processes simultaneously, this strategy involves selectively aborting one process at a time until the deadlock cycle is eliminated. However, this incurs overhead as a deadlock-detection algorithm must be invoked after each process termination to determine if any processes are still deadlocked.