Recovery from Deadlock

Recovery from Deadlock: Process Termination
• Abort all deadlocked processes.
• Abort one process at a time until the deadlock cycle is eliminated.
• In which order should we choose to abort?
– Priority of the process.
– How long process has computed, and how much longer to completion.
– Resources the process has used.
– Resources process needs to complete.
– How many processes will need to be terminated.
– Is process interactive or batch?

Recovery from Deadlock: Resource Preemption
• Selecting a victim – minimize cost
• Rollback – return to some safe state, restart process from that state
– Require the system to keep more information about the state of all the running processes
• Starvation – same process may always be picked as victim, include number of rollback in cost factor