On Thu, Mar 11, 2021 at 03:13:04PM +0000, Valentin Schneider wrote: > > #ifdef CONFIG_SCHED_SMT > > /* > > * When going down, decrement the number of cores with SMT present. > > > @@ -8206,7 +8212,7 @@ void __init sched_init(void) > > rq->sd = NULL; > > rq->rd = NULL; > > rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE; > > - rq->balance_callback = NULL; > > + rq->balance_callback = &balance_push_callback; > > rq->active_balance = 0; > > rq->next_balance = jiffies; > > rq->push_cpu = 0; > > @@ -8253,6 +8259,7 @@ void __init sched_init(void) > > > > #ifdef CONFIG_SMP > > idle_thread_set_boot_cpu(); > > + balance_push_set(smp_processor_id(), false); > > #endif > > init_sched_fair_class(); > > > > I don't get what these two changes do - the end result is the same as > before, no?
IIRC the idea was to initialize the offline CPUs to the same state as if they'd been offlined.
