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Subject: Re: [PATCH v2 1/5] sched/fair: Reorder enqueue/dequeue_task_fair path
To:     Vincent Guittot <vincent.guittot@linaro.org>, mingo@redhat.com,
        peterz@infradead.org, juri.lelli@redhat.com, rostedt@goodmis.org,
        bsegall@google.com, mgorman@suse.de, linux-kernel@vger.kernel.org
Cc:     pauld@redhat.com, parth@linux.ibm.com, valentin.schneider@arm.com,
        hdanton@sina.com
References: <20200214152729.6059-1-vincent.guittot@linaro.org>
 <20200214152729.6059-2-vincent.guittot@linaro.org>
From:   Dietmar Eggemann <dietmar.eggemann@arm.com>
Message-ID: <ee38d205-b356-9474-785e-e514d81b7d7f@arm.com>
Date:   Tue, 18 Feb 2020 13:37:37 +0100
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On 14/02/2020 16:27, Vincent Guittot wrote:
> The walk through the cgroup hierarchy during the enqueue/dequeue of a task
> is split in 2 distinct parts for throttled cfs_rq without any added value
> but making code less readable.
> 
> Change the code ordering such that everything related to a cfs_rq
> (throttled or not) will be done in the same loop.
> 
> In addition, the same steps ordering is used when updating a cfs_rq:
> - update_load_avg
> - update_cfs_group
> - update *h_nr_running

Is this code change really necessary? You pay with two extra goto's. We
still have the two for_each_sched_entity(se)'s because of 'if
(se->on_rq); break;'.

[...]