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SubjectRe: [PATCH 1/8] sched: introduce task_se_h_load helper
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On Wed, 2019-06-19 at 14:52 +0200, Dietmar Eggemann wrote:

> > @@ -7833,14 +7834,19 @@ static void update_cfs_rq_h_load(struct
> > cfs_rq *cfs_rq)
> > }
> > }
> >
> > -static unsigned long task_h_load(struct task_struct *p)
> > +static unsigned long task_se_h_load(struct sched_entity *se)
> > {
> > - struct cfs_rq *cfs_rq = task_cfs_rq(p);
> > + struct cfs_rq *cfs_rq = cfs_rq_of(se);
> >
> > update_cfs_rq_h_load(cfs_rq);
> > - return div64_ul(p->se.avg.load_avg * cfs_rq->h_load,
> > + return div64_ul(se->avg.load_avg * cfs_rq->h_load,
> > cfs_rq_load_avg(cfs_rq) + 1);
> > }
>
> I wonder if this is necessary. I placed a BUG_ON(!entity_is_task(se))
> into task_se_h_load() after I applied the whole patch-set and ran
> some
> taskgroup related testcases. It didn't hit.
>
> So why not use task_h_load(task_of(se)) instead?
>
> [...]

That would work, but task_h_load then dereferences
task->se to get the se->avg.load_avg value.

Going back to task from the se, only to then get the
se from the task seems a little unnecessary :)

Can you explain why you think task_h_load(task_of(se))
would be better? I think I may be overlooking something.

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