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

[Peter Zijlstra]

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 :-)