On Tue, Sep 10, 2013 at 10:31:41AM +0100, Mel Gorman wrote:
> @@ -5045,15 +5038,50 @@ static int need_active_balance(struct lb_env *env)
>
> static int active_load_balance_cpu_stop(void *data);
>
> +static int should_we_balance(struct lb_env *env)
> +{
> + struct sched_group *sg = env->sd->groups;
> + struct cpumask *sg_cpus, *sg_mask;
> + int cpu, balance_cpu = -1;
> +
> + /*
> + * In the newly idle case, we will allow all the cpu's
> + * to do the newly idle load balance.
> + */
> + if (env->idle == CPU_NEWLY_IDLE)
> + return 1;
> +
> + sg_cpus = sched_group_cpus(sg);
> + sg_mask = sched_group_mask(sg);
> + /* Try to find first idle cpu */
> + for_each_cpu_and(cpu, sg_cpus, env->cpus) {
> + if (!cpumask_test_cpu(cpu, sg_mask) || !idle_cpu(cpu))
> + continue;
> +
> + balance_cpu = cpu;
> + break;
> + }
> +
> + if (balance_cpu == -1)
> + balance_cpu = group_balance_cpu(sg);
> +
> + /*
> + * First idle cpu or the first cpu(busiest) in this sched group
> + * is eligible for doing load balancing at this and above domains.
> + */
> + return balance_cpu != env->dst_cpu;
> +}
> +
Hello, Mel.
There is one mistake from me.
The last return statement in should_we_balance() should be
'return balance_cpu == env->dst_cpu'. The fix was submitted yesterday.
You can get more information on below thread.
https://lkml.org/lkml/2013/9/10/1
I think that this fix is somewhat important to scheduler's behavior,
so it may be better to update your test result with this fix.
Sorry for notifying this.
Thanks.
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