linux-kernel - Re: [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum

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Date:   Mon, 13 Nov 2017 12:00:16 +0100
From:   Daniel Bristot de Oliveira <bristot@...hat.com>
To:     Byungchul Park <byungchul.park@....com>, peterz@...radead.org,
        mingo@...nel.org, rostedt@...dmis.org
Cc:     linux-kernel@...r.kernel.org, juri.lelli@...il.com,
        kernel-team@....com
Subject: Re: [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for
 clean-up

On 10/27/2017 10:38 AM, Byungchul Park wrote:
> On Tue, Oct 10, 2017 at 03:44:03PM +0900, Byungchul Park wrote:
>> Changes from v1
>>  - Enhance commit msg
>>  - Prevent WARN in cpumask_test_cpu() in cpudl_find() when best_cpu == -1
>>
>> -----8<-----
>> >From 7735382d07ae6a61d740ae39ba2ecf169d43b8a2 Mon Sep 17 00:00:00 2001
>> From: Byungchul Park <byungchul.park@....com>
>> Date: Wed, 22 Mar 2017 14:25:56 +0900
>> Subject: [RESEND PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up
>>
>> Current code uses cpudl_maximum() to get the root node's cpu, while it
>> directly accesses the root node like 'cp->elements[0].dl' to get the
>> root node's dl. It would be more readible to add a function for the dl,
>> as well. Added it.
> 
> Hello everyone,
> 
> Could you tell opinions?
> 
>> Signed-off-by: Byungchul Park <byungchul.park@....com>
>> Acked-by: Steven Rostedt (VMware) <rostedt@...dmis.org>

Acked-by: Daniel Bristot de Oliveira <bristot@...hat.com>

>> ---
>>  kernel/sched/cpudeadline.c | 11 ++++++++---
>>  1 file changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
>> index 8d9562d..9f02035 100644
>> --- a/kernel/sched/cpudeadline.c
>> +++ b/kernel/sched/cpudeadline.c
>> @@ -108,11 +108,16 @@ static void cpudl_heapify(struct cpudl *cp, int idx)
>>  		cpudl_heapify_down(cp, idx);
>>  }
>>  
>> -static inline int cpudl_maximum(struct cpudl *cp)
>> +static inline int cpudl_maximum_cpu(struct cpudl *cp)
>>  {
>>  	return cp->elements[0].cpu;
>>  }
>>  
>> +static inline u64 cpudl_maximum_dl(struct cpudl *cp)
>> +{
>> +	return cp->elements[0].dl;
>> +}
>> +
>>  /*
>>   * cpudl_find - find the best (later-dl) CPU in the system
>>   * @cp: the cpudl max-heap context
>> @@ -130,11 +135,11 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
>>  	    cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
>>  		return 1;
>>  	} else {
>> -		int best_cpu = cpudl_maximum(cp);
>> +		int best_cpu = cpudl_maximum_cpu(cp);
>>  		WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
>>  
>>  		if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
>> -		    dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
>> +		    dl_time_before(dl_se->deadline, cpudl_maximum_dl(cp))) {
>>  			if (later_mask)
>>  				cpumask_set_cpu(best_cpu, later_mask);
>>  
>> -- 
>> 1.9.1