Re: [PATCH 3/3] task: Clean house now that tasks on the runqueue are rcu protected

[Oleg Nesterov]

On 09/02, Eric W. Biederman wrote:
>
> @@ -1644,7 +1644,7 @@ static void task_numa_compare(struct task_numa_env *env,
>  		return;
>  
>  	rcu_read_lock();
> -	cur = task_rcu_dereference(&dst_rq->curr);
> +	cur = rcu_dereference(dst_rq->curr);
>  	if (cur && ((cur->flags & PF_EXITING) || is_idle_task(cur)))
>  		cur = NULL;

afaics rq->curr can't be NULL, so you can also simplify the "if" check

	cur = task_rcu_dereference(&dst_rq->curr);
	if ((cur->flags & PF_EXITING) || is_idle_task(cur))
		cur = NULL;

Same for membarrier_global_expedited/membarrier_private_expedited changed
by this patch.

Oleg.