Re: [RFC 1/8] sched: Add nice value change notifier

6 Oct 2021


      HI Tvrtko
On 2021/10/4 22:36, Tvrtko Ursulin wrote:
...
void set_user_nice(struct task_struct *p, long nice)
  {
   bool queued, running;

int old_prio;


int old_prio, ret;
struct rq_flags rf;
struct rq *rq;

@@ -6915,6 +6947,9 @@ void set_user_nice(struct task_struct *p, long nice)
out_unlock:
   task_rq_unlock(rq, p, &rf);


ret = atomic_notifier_call_chain(&user_nice_notifier_list, nice, p);
WARN_ON_ONCE(ret != NOTIFY_DONE);
}

How about adding a new "io_nice" to task_struct，and move the call chain to
sched_setattr/getattr, there are two benefits:
1. Decoupled with fair scheduelr. In our use case, high priority tasks often
    use rt scheduler.
2. The range of value don't need to be bound to -20~19 or 0~139

    