Mastering Linux Kernel Development

RR

The round-robin policy is similar to FIFO, with the only exception being that it is allocated a timeslice to run. This is kind of an enhancement to FIFO (as a FIFO process may run until it yields or waits). Similar to FIFO, the RR process at the head of the list is picked for execution (if no other higher-priority task is available) and on completion of the timeslice gets preempted and is added back to the tail end of the list. RR processes with the same priority run round robin until preempted by a high-priority task. When a high-priority task preempts an RR task, it waits at the head of the list, and on resumption runs for the remainder of its timeslice only.