Re: [PATCH v2] sched/core: Preempt current task in favour of bound kthread

Peter Zijlstra
2019-12-10T09:33:53Z

On Tue, Dec 10, 2019 at 10:26:01AM +0100, Peter Zijlstra wrote:

> > @@ -6716,7 +6737,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
> > find_matching_se(&se, &pse);
> > update_curr(cfs_rq_of(se));
> > BUG_ON(!pse);
> > - if (wakeup_preempt_entity(se, pse) == 1) {
> > + if (wakeup_preempt_entity(se, pse) == 1 || kthread_wakeup_preempt(rq, p, wake_flags)) {
> > /*
> > * Bias pick_next to pick the sched entity that is
> > * triggering this preemption.
>
> How about something like:
>
if (wakeup_preempt_entity(se, pse) >= !(wake_flags & WF_KTHREAD))

That's a slightly less convoluted expression for the same value :-)