Re: [PATCH 11/19] sched/fair: Identify busiest sched_group for LLC-aware load balancing

[Tim Chen]

On Wed, 2025-10-15 at 17:24 +0200, Peter Zijlstra wrote:
> On Sat, Oct 11, 2025 at 11:24:48AM -0700, Tim Chen wrote:
> 
> > @@ -11035,6 +11059,17 @@ static bool update_sd_pick_busiest(struct lb_env *env,
> >  	     sds->local_stat.group_type != group_has_spare))
> >  		return false;
> >  
> > +	/* deal with prefer LLC load balance, if failed, fall into normal load balance */
> > +	if (update_llc_busiest(env, busiest, sgs))
> > +		return true;
> > +
> > +	/*
> > +	 * If the busiest group has tasks with LLC preference,
> > +	 * skip normal load balance.
> > +	 */
> > +	if (busiest->group_llc_balance)
> > +		return false;
> > +
> >  	if (sgs->group_type > busiest->group_type)
> >  		return true;
> 
> This feels weird.. should we really override things like group_imbalance
> or group_misfit_task ?

Probably make sense to move the group_llc_balance priority to be lower than group_imblanace
and group_misfit_task. Will update accordingly.

Tim