linux-kernel - Re: [PATCH 1/3] sched: Add new API wake_up_if

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <540860AC.3030905@linaro.org>
Date:	Thu, 04 Sep 2014 14:53:00 +0200
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	Chuansheng Liu <chuansheng.liu@...el.com>, peterz@...radead.org,
	luto@...capital.net, rjw@...ysocki.net, mingo@...hat.com
CC:	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	changcheng.liu@...el.com, xiaoming.wang@...el.com,
	souvik.k.chakravarty@...el.com
Subject: Re: [PATCH 1/3] sched: Add new API wake_up_if_idle() to wake up the
 idle cpu

On 09/04/2014 09:17 AM, Chuansheng Liu wrote:
> Implementing one new API wake_up_if_idle(), which is used to
> wake up the idle CPU.
>
> Suggested-by: Andy Lutomirski <luto@...capital.net>
> Signed-off-by: Chuansheng Liu <chuansheng.liu@...el.com>

Hi Chuanseng,

in the future, please prefix the patches with the version number and a 
changelog.

Thanks

   -- Daniel

Acked-by: Daniel Lezcano <daniel.lezcano@...aro.org>

> ---
>   include/linux/sched.h |    1 +
>   kernel/sched/core.c   |   19 +++++++++++++++++++
>   2 files changed, 20 insertions(+)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 857ba40..3f89ac1 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -1024,6 +1024,7 @@ struct sched_domain_topology_level {
>   extern struct sched_domain_topology_level *sched_domain_topology;
>
>   extern void set_sched_topology(struct sched_domain_topology_level *tl);
> +extern void wake_up_if_idle(int cpu);
>
>   #ifdef CONFIG_SCHED_DEBUG
>   # define SD_INIT_NAME(type)		.name = #type
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 1211575..b818548 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -1620,6 +1620,25 @@ static void ttwu_queue_remote(struct task_struct *p, int cpu)
>   	}
>   }
>
> +void wake_up_if_idle(int cpu)
> +{
> +	struct rq *rq = cpu_rq(cpu);
> +	unsigned long flags;
> +
> +	if (!is_idle_task(rq->curr))
> +		return;
> +
> +	if (set_nr_if_polling(rq->idle)) {
> +		trace_sched_wake_idle_without_ipi(cpu);
> +	} else {
> +		raw_spin_lock_irqsave(&rq->lock, flags);
> +		if (is_idle_task(rq->curr))
> +			smp_send_reschedule(cpu);
> +		/* Else cpu is not in idle, do nothing here */
> +		raw_spin_unlock_irqrestore(&rq->lock, flags);
> +	}
> +}
> +
>   bool cpus_share_cache(int this_cpu, int that_cpu)
>   {
>   	return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
>


-- 
  <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/