Post Syndicated from corbet original https://lwn.net/Articles/979532/

Changwoo Min has posted an
introduction to writing custom schedulers with sched_ext.

In a particular situation, when each scheduling policy needs its
specific action, the core kernel scheduler calls an operation
defined in struct sched_class. For example, when the core
kernel scheduler needs to select a task to be scheduled, it calls
the sched_class.pick_next_task(rq) callback of a concrete
scheduling policy. When a task becomes runnable, the core kernel
scheduler calls sched_class.enqueue(rq, p, flags) so the
concrete scheduling policy enqueues task p to run queue
rq. When a task’s runtime state needs to be updated, the
core kernel scheduler calls sched_class.update_curr(rq).