Re: [PATCH v3 4/6] sched/fair: Carve out logic to mark a group for asymmetric packing

[Ricardo Neri <ricardo.neri-calderon@linux.intel.com>]

On Mon, May 17, 2021 at 04:21:36PM +0200, Dietmar Eggemann wrote:
> On 13/05/2021 17:49, Ricardo Neri wrote:
> 
> [...]
> 
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index c8c04e9d0d3b..c8b66a5d593e 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -8447,6 +8447,20 @@ group_type group_classify(unsigned int imbalance_pct,
> >  	return group_has_spare;
> >  }
> >  
> > +static inline bool
> > +sched_asym(struct lb_env *env, struct sd_lb_stats *sds,  struct sg_lb_stats *sgs,
> > +	   struct sched_group *group)
> > +{
> > +	/*
> > +	 * Because sd->groups starts with the local group, anything that isn't
> > +	 * the local group will have access to the local state.
> > +	 */
> > +	if (group == sds->local)
> > +		return false;
> 
> sched_asym() is called under if(!local_group ...) from
> update_sg_lb_stats(). So why checking this here again?

This is true. It looks to me that this check is not needed. I makes
sense to me to keep the check in update_sg_lb_stats() so that we can
avoid the extra checks, right?

Thanks and BR,
Ricardo