Re: [PATCH 07/15] sched/smp: Use lag to simplify cross-runqueue placement

From: Peter Zijlstra
Date: Wed Sep 13 2023 - 05:04:14 EST


On Tue, Sep 12, 2023 at 05:32:21PM +0200, Sebastian Andrzej Siewior wrote:
> On 2023-05-31 13:58:46 [+0200], Peter Zijlstra wrote:
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -12492,22 +12440,9 @@ static void task_fork_fair(struct task_s
> >
> > cfs_rq = task_cfs_rq(current);
> > curr = cfs_rq->curr;
> > - if (curr) {
> > + if (curr)
> > update_curr(cfs_rq);
> > - se->vruntime = curr->vruntime;
> > - }
> > place_entity(cfs_rq, se, 1);
> > -
> > - if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) {
>
> Since the removal of sysctl_sched_child_runs_first there is no user of
> this anymore. There is still the sysctl file sched_child_runs_first with
> no functionality.
> Is this intended or should it be removed?

Hurmph... I think that knob has been somewat dysfunctional for a long
while and it might be time to remove it.

Ingo?