I am using Linux 4.19.2 https://elixir.bootlin.com/linux/v4.19.2/ident/
I figured out the structure called task_struct which contains all the information in the Process Control Block. When we create a new process, the fork() function is called, which in turn, calls functions like _do_fork() and copy_process() to provide values for the fields in task_struct.
However, I couldn't find out where is the priority of a new process. The field name used for priority in the task_struct structure is prio. Where does it get its value from, when a process is started?