Re: [PATCH 04/11] cpuset: update cs->real_{cpus,mems}_allowed when config changes

[Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Wed, Aug 21, 2013 at 05:59:32PM +0800, Li Zefan wrote:
...
> +	cpuset_for_each_descendant_pre(cp, pos_css, cs) {
> +		struct cpuset *parent = parent_cs(cs);
> +		struct cpumask *new_cpus = trialcs->real_cpus_allowed;
> +
> +		cpumask_and(new_cpus, cp->cpus_allowed,
> +			    parent->real_cpus_allowed);
> +
> +		/*
> +		 * Skip the whole subtree if the cpumask is not changed, unless
> +		 * it's empty, and in this case we need to update tasks to take
> +		 * on an ancestor's cpumask.

Something like the following would be clearer?

"Skip the whole subtree if the cpumask remains the same and isn't
empty.  If empty, we need..."

> @@ -931,7 +941,6 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
>  {
>  	struct ptr_heap heap;
>  	int retval;
> -	int is_load_balanced;
>  
>  	/* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */
>  	if (cs == &top_cpuset)
> @@ -966,17 +975,15 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
>  	if (retval)
>  		return retval;
>  
> -	is_load_balanced = is_sched_load_balance(trialcs);
> -
>  	mutex_lock(&callback_mutex);
>  	cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
>  	mutex_unlock(&callback_mutex);
>  
> -	update_tasks_cpumask_hier(cs, true, &heap);
> +	update_cpumasks_hier(cs, trialcs, &heap);
>  
>  	heap_free(&heap);
>  
> -	if (is_load_balanced)
> +	if (is_sched_load_balance(cs))
>  		rebuild_sched_domains_locked();

Hmmm... Maybe the above change needs some explanation in the patch
description?

Ooh and @update_root params are gone.  Maybe nice to note that in the
description too?

Thanks.

-- 
tejun