At least one resource must be held in a non-shareable mode.
This means that only oneProcess (进程) can use the resource at any given time
If another process requests the resource, that process must wait until the resource has been released
Hold and Wait
A process must be holding at least one resource and waiting to acquire additional resources that are currently being held by other processes
No Preemption
Resources cannot be preempted from a process. They can only be released by the process holding them, typically after the process has finished its task.
Circular Wait
There exists a set of waiting processes such that P0 is waiting for a resource held by P1, P1 is waiting for a resource held by P2, and so on, with Pn waiting for a resource held by P0
Handling Strategies
Prevention
Ensure that at least one of the [Coffman conditions does not hold. For example, by implementing a resource allocation policy that ensures no Circular Wait
Avoidance
The system has some additional a prior information available.
The most famous algorithm used for deadlock avoidance is the Banker’s Algorithm
Detection
The system periodically checks for Deadlock (死锁). If detected, actions are taken to recover from it
Ignorance
Simply ignore the problem and assume Deadlock (死锁) will never occur.
This is suitable for some environments where deadlocks are rare and the overhead of other handling strategies is not justified
