Re: [PATCH v7 02/15] sched/core: uclamp: Enforce last task UCLAMP_MAX

Suren Baghdasaryan
2019-03-14T00:29:02Z

On Wed, Mar 13, 2019 at 9:16 AM Patrick Bellasi <patrick.bellasi@arm.com> wrote:
>
> On 13-Mar 15:12, Peter Zijlstra wrote:
> > On Fri, Feb 08, 2019 at 10:05:41AM +0000, Patrick Bellasi wrote:
> > > +static inline void uclamp_idle_reset(struct rq *rq, unsigned int clamp_id,
> > > + unsigned int clamp_value)
> > > +{
> > > + /* Reset max-clamp retention only on idle exit */
> > > + if (!(rq->uclamp_flags & UCLAMP_FLAG_IDLE))
> > > + return;
> > > +
> > > + WRITE_ONCE(rq->uclamp[clamp_id].value, clamp_value);
> > > +
> > > + /*
> > > + * This function is called for both UCLAMP_MIN (before) and UCLAMP_MAX
> > > + * (after). The idle flag is reset only the second time, when we know
> > > + * that UCLAMP_MIN has been already updated.
> >
> > Why do we care? That is, what is this comment trying to tell us.
>
> Right, the code is clear enough, I'll remove this comment.

It would be probably even clearer if rq->uclamp_flags &=
~UCLAMP_FLAG_IDLE is done from inside uclamp_rq_inc after
uclamp_rq_inc_id for both clamps is called.

> >
> > > + */
> > > + if (clamp_id == UCLAMP_MAX)
> > > + rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE;
> > > +}
>
> --
> #include <best/regards.h>
>
> Patrick Bellasi