Mastering Linux Kernel Development

The scheduler's entry point

The process of scheduling starts with a call to the generic scheduler, that is, the schedule() function, defined in <kernel/sched/core.c>. This is perhaps one of the most invoked routines in the kernel. The functionality of schedule() is to pick the next best runnable task. The pick_next_task() of the schedule() function iterates through all the corresponding functions contained in the scheduler classes and ends up picking the next best task to run. Each scheduler class is linked using a single linked list, which enables the pick_next_task() to iterate through these classes.

Considering that Linux was primarily designed to cater to highly interactive systems, the function first looks for the next best runnable ...