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Date:   Tue, 12 May 2020 15:48:05 +0530
From:   Pavan Kondeti <pkondeti@codeaurora.org>
To:     Vincent Guittot <vincent.guittot@linaro.org>
Cc:     mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
        dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com,
        mgorman@suse.de, linux-kernel@vger.kernel.org, pauld@redhat.com,
        ouwen210@hotmail.com
Subject: Re: [PATCH] sched/fair: enqueue_task_fair optimization
Message-ID: <20200512101805.GB31725@codeaurora.org>
References: <20200511192301.1009-1-vincent.guittot@linaro.org>
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On Mon, May 11, 2020 at 09:23:01PM +0200, Vincent Guittot wrote:
> enqueue_task_fair() jumps to enqueue_throttle when cfs_rq_of(se) is
> throttled, which means that se can't be NULL and we can skip the test.
> 
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
>  kernel/sched/fair.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 4b73518aa25c..910bbbe50365 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -5512,7 +5512,6 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
>                         list_add_leaf_cfs_rq(cfs_rq);
>  	}
>  
> -enqueue_throttle:
>  	if (!se) {
>  		add_nr_running(rq, 1);
>  		/*
> @@ -5534,6 +5533,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
>  
>  	}
>  
> +enqueue_throttle:
>  	if (cfs_bandwidth_used()) {
>  		/*
>  		 * When bandwidth control is enabled; the cfs_rq_throttled()

Right, se can't be NULL when we break upon throttling. Looks good to me.

Thanks,
Pavan

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