Re: [PATCH] numa,sched: only consider less busy nodes as numa balancing destination

[Peter Zijlstra <peterz@infradead.org>]

On Wed, May 13, 2015 at 08:29:06AM +0200, Peter Zijlstra wrote:
> @@ -1572,9 +1582,10 @@ static void numa_migrate_preferred(struct task_struct *p)
>   * are added when they cause over 6/16 of the maximum number of faults, but
>   * only removed when they drop below 3/16.
>   */
> -static void update_numa_active_node_mask(struct numa_group *numa_group)
> +static bool update_numa_active_node_mask(struct numa_group *numa_group)
>  {
>  	unsigned long faults, max_faults = 0;
> +	bool update = false;
>  	int nid;
>  
>  	for_each_online_node(nid) {
> @@ -1586,11 +1597,17 @@ static void update_numa_active_node_mask(struct numa_group *numa_group)
>  	for_each_online_node(nid) {
>  		faults = group_faults_cpu(numa_group, nid);
>  		if (!node_isset(nid, numa_group->active_nodes)) {
> -			if (faults > max_faults * 6 / 16)
> +			if (faults > max_faults * 6 / 16) {
>  				node_set(nid, numa_group->active_nodes);
> -		} else if (faults < max_faults * 3 / 16)
> +				update = true;
> +			}
> +		} else if (faults < max_faults * 3 / 16) {
>  			node_clear(nid, numa_group->active_nodes);
> +			update = true;
> +		}
>  	}
> +
> +	return update;
>  }
>  
>  /*

Ignore these hunks, they're dead wood.