PPT Slide
Deadlock Recovery
- Deadlock detection & recovery is optimistic; assumes no deadlock will occur. VMS uses a timer of 10 seconds after a resource request is started. If when the timer goes off the request is still not granted then the deadlock detection/recovery algorithm is invoked.
- Recovery from the deadlock can involve a number of techniques:
- Rollback - return a process back to an earlier point in execution before the deadlock occurs; perhaps a future allocation will avoid the deadlock. This is an expensive proposition!
- Process termination - kill one or more processes until the deadlock is broken.