Re: [PATCH v2 2/6] sched: explicitly cpu_idle_type checking in rebalance_domains()

[Peter Zijlstra <peterz@infradead.org>]

On Tue, 2013-03-26 at 15:01 +0900, Joonsoo Kim wrote:
> @@ -5506,10 +5506,10 @@ static void rebalance_domains(int cpu, enum
> cpu_idle_type idle)
>                 if (time_after_eq(jiffies, sd->last_balance +
> interval)) {
>                         if (load_balance(cpu, rq, sd, idle, &balance))
> {
>                                 /*
> -                                * We've pulled tasks over so either
> we're no
> -                                * longer idle.
> +                                * We've pulled tasks over so either
> we may
> +                                * be no longer idle.
>                                  */

That comment didn't make sense and it does even less now.

How about we make that:

  /*
   * The LBF_SOME_PINNED logic could have changed
   * env->dst_cpu, so we can't know our idle state
   * even if we migrated tasks; update it.
   */

> -                               idle = CPU_NOT_IDLE;
> +                               idle = idle_cpu(cpu) ? CPU_IDLE :
> CPU_NOT_IDLE;
>                         }
>                         sd->last_balance = jiffies;
>                 }