Deadlock Conditions, Prevention and Avoidance

互相持有并等待某些不能被强抢或共用的资源
Hold and circularly waiting for some mutually exclusive non-preemptive resource

Hold and Wait
Holding some resources and waiting for some other resources

Circular Waiting
Circular dependencies exists, represented by some graphs

Mutual Exclusion
Resource cannot be shared, cannot be used at the same time by two entities

No Preemption
Resource cannot be taken by other before releasing. i.e. no once has authority or higher power