Re: [PATCH 2/2] sched: fix a logical error in select_task_rq_fair

From: Alex Shi
Date: Thu Jul 26 2012 - 05:11:42 EST


On 07/26/2012 04:17 PM, Peter Zijlstra wrote:

> On Thu, 2012-07-26 at 13:27 +0800, Alex Shi wrote:
>> If find_idlest_cpu() return '-1', and sd->child is NULL. The function
>> select_task_rq_fair will return -1. That is not the function's purpose.
>
> But find_idlest_cpu() will only return -1 if the group mask is fully
> excluded by the cpus_allowed mask, right?


Yes.

>
> In that case aren't we covering up a bug in find_idlest_group(), it
> appears to have returned a group that isn't eligible to be idlest.


If it is possible happening in sched_domain rebuilding?
I didn't meet this bug. Just guess.

>
>


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