Writers' Preferred - A little bit complicated, it needs a queue.
Deadlock is one area where there is strong theory, but it's almost completely ignored in practice.
P1 grabs the memory it needs. P2 grabs the disk space it needs. P3 grabs the tape drive it needs. Each waits for the other to release to acquire the rest of the necessary resources. As long as a larger brother wants to eat, you can't.