Real-Time Scheduling Class

As mandated by the POSIX standard, Linux supports two real-time scheduling classes in addition to
‘‘normal‘‘ processes. The structure of the scheduler enables real-time processes to be integrated into the
kernel without any changes in the core scheduler — this is a definitive advantage of scheduling classes.

Real-time processes can be identified
by the fact that they have a higher priority than normal processes — accordingly, their static_prio
value is always lower than that of normal processes

The rt_task macro is provided to establish whether a given task is a real-time process or not by inspecting its priority, and
task_has_rt_policy checks if the process is associated with a real-time scheduling policy.