Re: [PATCH v2 12/23] sched/cache: Add migrate_llc_task migration type for cache-aware balancing

[Chen, Yu C]

On 12/10/2025 9:32 PM, Peter Zijlstra wrote:
> On Wed, Dec 03, 2025 at 03:07:31PM -0800, Tim Chen wrote:
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index db555c11b5b8..529adf342ce0 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -9547,7 +9547,8 @@ enum migration_type {
> >   	migrate_load = 0,
> >   	migrate_util,
> >   	migrate_task,
> > -	migrate_misfit
> > +	migrate_misfit,
> > +	migrate_llc_task
> >   };
> >   
> >   #define LBF_ALL_PINNED	0x01
> > @@ -10134,6 +10135,10 @@ static int detach_tasks(struct lb_env *env)
> >   			env->imbalance -= util;
> >   			break;
> >   
> > +		case migrate_llc_task:
> > +			env->imbalance--;
> > +			break;
> > +
> >   		case migrate_task:
> >   			env->imbalance--;
> >   			break;
>
> > @@ -12181,6 +12199,16 @@ static struct rq *sched_balance_find_src_rq(struct lb_env *env,
> >   			}
> >   			break;
> >   
> > +		case migrate_llc_task:
> > +#ifdef CONFIG_SCHED_CACHE
> > +			dst_llc = llc_id(env->dst_cpu);
> > +			if (dst_llc >= 0 &&
> > +			    busiest_pref_llc < rq->nr_pref_llc[dst_llc]) {
> > +				busiest_pref_llc = rq->nr_pref_llc[dst_llc];
> > +				busiest = rq;
> > +			}
> > +#endif
> > +			break;
> >   		case migrate_task:
> >   			if (busiest_nr < nr_running) {
> >   				busiest_nr = nr_running;
> > @@ -12363,6 +12391,8 @@ static void update_lb_imbalance_stat(struct lb_env *env, struct sched_domain *sd
> >   	case migrate_misfit:
> >   		__schedstat_add(sd->lb_imbalance_misfit[idle], env->imbalance);
> >   		break;
> > +	case migrate_llc_task:
> > +		break;
> >   	}
> >   }
>
> The enum and all switch statements had the same order; you wrecked it!

OK, will fix the order.

Thanks,
Chenyu