Deadlock Handling Deadlocks are situations where multiple threads or processes are indefinitely blocked, waiting for resources held by each other. This can d...
Deadlocks are situations where multiple threads or processes are indefinitely blocked, waiting for resources held by each other. This can deadlock the system, preventing any further progress.
Causes of Deadlock:
Mutual Exclusion: Threads or processes can hold a resource exclusively, preventing others from acquiring it.
Hold and Wait: Threads are waiting for resources held by other threads or processes, and each holds a resource while waiting.
Circular Dependencies: Threads are waiting for resources held by other threads, but those other threads are waiting for resources held by the first thread.
Effects of Deadlock:
System unresponsive: No further transactions can be processed.
Resource starvation: One or more threads are starved of resources, leading to performance degradation.
Data integrity issues: Deadlocks can cause lost or corrupted data.
Deadlock Handling Techniques:
Resource ordering: Threads acquire resources in a specific order, ensuring they acquire resources in the order they are released.
Deadlock detection: Systems employ algorithms to identify deadlocks early on.
Deadlock prevention: Strategies are implemented to avoid situations that can lead to deadlocks.
Deadlock recovery: When a deadlock is detected, mechanisms are used to recover the system and resume normal operation.
Example:
Imagine two threads, A and B, waiting for resources held by each other. Thread A holds resource X and thread B holds resource Y. However, thread B needs resource Z held by thread A for its next step. Similarly, thread A needs resource W held by thread B for its operation. This creates a deadlock where neither thread can proceed.
Key Takeaways:
Deadlocks are a serious issue that can halt system performance.
Causes of deadlocks include mutual exclusion, hold and wait, and circular dependencies.
Deadlock handling techniques aim to prevent, detect, and recover from deadlocks