Re: [PATCH v2 1/2] sched/deadline: Add cpudl_maximum_dl() for clean-up

From: Steven Rostedt
Date: Mon Sep 18 2017 - 10:48:06 EST


On Thu, 14 Sep 2017 10:05:18 +0900
Byungchul Park <byungchul.park@xxxxxxx> 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@xxxxxxx>
> Date: Wed, 22 Mar 2017 14:25:56 +0900
> Subject: [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.

Looks fine to me.

Acked-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>

-- Steve

>
> Signed-off-by: Byungchul Park <byungchul.park@xxxxxxx>
> ---
> 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);
>