Re: [PATCH -V11 2/9] mm/migrate: update node demotion order on hotplug events

[Dave Hansen]

On 3/8/22 02:27, Oscar Salvador wrote:
> @@ -2043,7 +2044,12 @@ static void __init init_cpu_node_state(void)
>  static int vmstat_cpu_online(unsigned int cpu)
>  {
>  	refresh_zone_stat_thresholds();
> -	node_set_state(cpu_to_node(cpu), N_CPU);
> +
> +	if (!node_state(cpu_to_node(cpu), N_CPU)) {
> +		node_set_state(cpu_to_node(cpu), N_CPU);
> +		set_migration_target_nodes();
> +	}
> +
>  	return 0;
>  }
> 
> @@ -2066,6 +2072,8 @@ static int vmstat_cpu_dead(unsigned int cpu)
>  		return 0;
> 
>  	node_clear_state(node, N_CPU);
> +	set_migration_target_nodes();
> +
>  	return 0;
>  }

Yeah, those callbacks do look like they're reinventing the wheel.  This
is a much more direct way of doing it.