Date: Thu, 31 Aug 2017 09:54:40 -0400
From: Josef Bacik <josef@toxicpanda.com>
To: Brendan Jackman <brendan.jackman@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>, Peter Zijlstra <peterz@infradead.org>,
        linux-kernel@vger.kernel.org,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Josef Bacik <josef@toxicpanda.com>,
        Morten Rasmussen <morten.rasmussen@arm.com>
Subject: Re: [PATCH v3 4/5] sched/fair: Fix use of find_idlest_group when no
 groups are allowed
Message-ID: <20170831135440.t5mhrhuofudxlgy4@destiny>
References: <20170831115802.26365-1-brendan.jackman@arm.com>
 <20170831115802.26365-5-brendan.jackman@arm.com>
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On Thu, Aug 31, 2017 at 12:58:01PM +0100, Brendan Jackman wrote:
> When p is allowed on none of the CPUs in the sched_domain, we
> currently return NULL from find_idlest_group, and pointlessly
> continue the search on lower sched_domain levels (where p is also not
> allowed) before returning prev_cpu regardless (as we have not updated
> new_cpu).
> 
> Add an explicit check for this case, and a comment to
> find_idlest_group. Now when find_idlest_group returns NULL, it always
> means that the local group is allowed and idlest.
> 

Reviewed-by: Josef Bacik <jbacik@fb.com>

Thanks,

Josef