linux-kernel - Re: [PATCH v3 2/6] sched/fair: Fix NO_RUN_TO

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Message-ID: <CAKfTPtCCWZWCft2GbCQL9Pqe9g_xi-pkCB50AQR9UEnmywqRYQ@mail.gmail.com>
Date: Wed, 9 Jul 2025 11:32:16 +0200
From: Vincent Guittot <vincent.guittot@...aro.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: mingo@...hat.com, juri.lelli@...hat.com, dietmar.eggemann@....com, 
	rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de, vschneid@...hat.com, 
	dhaval@...nis.ca, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/6] sched/fair: Fix NO_RUN_TO_PARITY case

On Wed, 9 Jul 2025 at 11:17, Peter Zijlstra <peterz@...radead.org> wrote:
>
> On Tue, Jul 08, 2025 at 06:56:26PM +0200, Vincent Guittot wrote:
>
> >  static inline void set_protect_slice(struct sched_entity *se)
> >  {
> > -     se->vlag = se->deadline;
> > +     u64 quantum = se->slice;
> > +
> > +     if (!sched_feat(RUN_TO_PARITY))
> > +             quantum = min(quantum, normalized_sysctl_sched_base_slice);
> > +
> > +     if (quantum != se->slice)
> > +             se->vprot = min_vruntime(se->deadline, se->vruntime + calc_delta_fair(quantum, se));
> > +     else
> > +             se->vprot = se->deadline;
> >  }
>
> I've done s/quantum/slice/ on the whole series. In the end this thing:
>
> > +static inline bool resched_next_quantum(struct cfs_rq *cfs_rq, struct sched_entity *curr)
>
> is gone, and *_protect_slice() has slice in the name, and its mostly
> assigned from slice named variables.
>
> Final form ends up looking like so:
>
> static inline void set_protect_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
> {
>         u64 slice = normalized_sysctl_sched_base_slice;
>         u64 vprot = se->deadline;
>
>         if (sched_feat(RUN_TO_PARITY))
>                 slice = cfs_rq_min_slice(cfs_rq);
>
>         slice = min(slice, se->slice);
>         if (slice != se->slice)
>                 vprot = min_vruntime(vprot, se->vruntime + calc_delta_fair(slice, se));
>
>         se->vprot = vprot;
> }

ok, looks good to me

>
> I'll run a few compiles and then push out to queue/sched/core (and stick
> the ttwu bits in queue/sched/ttwu -- as I should've done earlier).