linux-kernel - Re: [PATCH 6/7] sched/deadline: depend on clearing throttled status in replenish_dl

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Date:	Tue, 21 Apr 2015 16:10:21 +0800
From:	Wanpeng Li <wanpeng.li@...ux.intel.com>
To:	Juri Lelli <juri.lelli@....com>
Cc:	Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org, Juri Lelli <juri.lelli@....com>
Subject: Re: [PATCH 6/7] sched/deadline: depend on clearing throttled status
 in replenish_dl_entity

Hi Juri,
On Tue, Apr 21, 2015 at 09:16:47AM +0100, Juri Lelli wrote:
>Hi,
>
>On 06/04/2015 09:53, Wanpeng Li wrote:
>> Since the natural place to clear ->dl_throttled is in replenish_dl_entity(), and 
>> the task which is adjusted the priority is the current, it will be dequeued and 
>> then enqueued w/ replenish which can guarantee ->dl_throttled can be cleared, 
>> this patch drop the clear throttled status in function rt_mutex_setprio.
>> 
>
>Patch looks good. But, I'd slightly change subject and changelog. Something like
>this, maybe?
>
>sched/core: remove superfluous resetting of dl_throttled flag
>
>Resetting dl_throttled flag in rt_mutex_setprio (for a task that is going
>to be boosted) is superfluous, as the natural place to do so is in
>replenish_dl_entity(). If the task was on the runqueue and it is boosted
>by a DL task, it will be enqueued back with ENQUEUE_REPLENISH flag set,
>which can guarantee that dl_throttled is reset in replenish_dl_entity().
>
>This patch drops the resetting of throttled status in function
>rt_mutex_setprio().

Cool, many thanks for your review. :)

Regards,
Wanpeng Li 

>
>Thanks,
>
>- Juri
>
>> Signed-off-by: Wanpeng Li <wanpeng.li@...ux.intel.com>
>> ---
>>  kernel/sched/core.c | 1 -
>>  1 file changed, 1 deletion(-)
>> 
>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>> index 28b0d75..f1b9222 100644
>> --- a/kernel/sched/core.c
>> +++ b/kernel/sched/core.c
>> @@ -3037,7 +3037,6 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
>>  		if (!dl_prio(p->normal_prio) ||
>>  		    (pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) {
>>  			p->dl.dl_boosted = 1;
>> -			p->dl.dl_throttled = 0;
>>  			enqueue_flag = ENQUEUE_REPLENISH;
>>  		} else
>>  			p->dl.dl_boosted = 0;
>> 
--
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