linux-kernel - Re: [RESEND PATCH v3 1/2] sched/deadline: Add cpudl_maximum

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Date:   Fri, 22 Dec 2017 15:53:11 +0900
From:   Byungchul Park <byungchul.park@....com>
To:     peterz@...radead.org, mingo@...nel.org, rostedt@...dmis.org
Cc:     tglx@...utronix.de, raistlin@...ux.it,
        linux-kernel@...r.kernel.org, juri.lelli@...il.com,
        bristot@...hat.com, kernel-team@....com
Subject: Re: [RESEND PATCH v3 1/2] sched/deadline: Add cpudl_maximum_dl() for
 clean-up

On Tue, Dec 19, 2017 at 10:19:23AM +0900, Byungchul Park wrote:
> Changes from v2
>  - Run spellchecker over the text and fix typos
>  - Add acked-by Daniel
> 
> Changes from v1
>  - Enhance commit msg
>  - Prevent WARN in cpumask_test_cpu() in cpudl_find() when best_cpu == -1

Hello, shall I stop sending this? Let me know if so.

> -----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 v3 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 readable to add a function for the dl,
> as well. Added it.
> 
> 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