From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Chuansheng Liu <chuansheng.liu@intel.com>,
peterz@infradead.org, luto@amacapital.net, rjw@rjwysocki.net,
mingo@redhat.com
Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
changcheng.liu@intel.com, xiaoming.wang@intel.com,
souvik.k.chakravarty@intel.com
Subject: Re: [PATCH 2/3] smp: Adding new function wake_up_all_idle_cpus()
Date: Thu, 04 Sep 2014 14:56:17 +0200 [thread overview]
Message-ID: <54086171.20107@linaro.org> (raw)
In-Reply-To: <1409815075-4180-2-git-send-email-chuansheng.liu@intel.com>
On 09/04/2014 09:17 AM, Chuansheng Liu wrote:
> Currently kick_all_cpus_sync() can break non-polling idle cpus
> thru IPI interrupts.
>
> But sometimes we need to break the polling idle cpus immediately
> to reselect the suitable c-state, also for non-idle cpus, we need
> to do nothing if we try to wake up them.
>
> Here adding one new function wake_up_all_idle_cpus() to let all cpus
> out of idle based on function wake_up_if_idle().
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
> ---
> include/linux/smp.h | 2 ++
> kernel/smp.c | 22 ++++++++++++++++++++++
> 2 files changed, 24 insertions(+)
>
> diff --git a/include/linux/smp.h b/include/linux/smp.h
> index 34347f2..93dff5f 100644
> --- a/include/linux/smp.h
> +++ b/include/linux/smp.h
> @@ -100,6 +100,7 @@ int smp_call_function_any(const struct cpumask *mask,
> smp_call_func_t func, void *info, int wait);
>
> void kick_all_cpus_sync(void);
> +void wake_up_all_idle_cpus(void);
>
> /*
> * Generic and arch helpers
> @@ -148,6 +149,7 @@ smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
> }
>
> static inline void kick_all_cpus_sync(void) { }
> +static inline void wake_up_all_idle_cpus(void) { }
>
> #endif /* !SMP */
>
> diff --git a/kernel/smp.c b/kernel/smp.c
> index aff8aa1..9e0d0b2 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -13,6 +13,7 @@
> #include <linux/gfp.h>
> #include <linux/smp.h>
> #include <linux/cpu.h>
> +#include <linux/sched.h>
>
> #include "smpboot.h"
>
> @@ -699,3 +700,24 @@ void kick_all_cpus_sync(void)
> smp_call_function(do_nothing, NULL, 1);
> }
> EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
> +
> +/**
> + * wake_up_all_idle_cpus - break all cpus out of idle
> + * wake_up_all_idle_cpus try to break all cpus which is in idle state even
> + * including idle polling cpus, for non-idle cpus, we will do nothing
> + * for them.
> + */
> +void wake_up_all_idle_cpus(void)
> +{
> + int cpu;
> +
> + preempt_disable();
> + for_each_online_cpu(cpu) {
> + if (cpu == smp_processor_id())
> + continue;
> +
> + wake_up_if_idle(cpu);
> + }
> + preempt_enable();
> +}
> +EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus);
>
--
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next prev parent reply other threads:[~2014-09-04 12:56 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-04 7:17 [PATCH 1/3] sched: Add new API wake_up_if_idle() to wake up the idle cpu Chuansheng Liu
2014-09-04 7:17 ` [PATCH 2/3] smp: Adding new function wake_up_all_idle_cpus() Chuansheng Liu
2014-09-04 12:56 ` Daniel Lezcano [this message]
2014-09-19 11:44 ` [tip:sched/core] smp: Add new wake_up_all_idle_cpus() function tip-bot for Chuansheng Liu
2014-09-04 7:17 ` [PATCH 3/3] cpuidle: Using the wake_up_all_idle_cpus() to wake up all idle cpus Chuansheng Liu
2014-09-04 13:01 ` Daniel Lezcano
2014-09-04 13:39 ` Liu, Chuansheng
2014-09-04 13:39 ` Liu, Chuansheng
2014-09-04 15:47 ` Peter Zijlstra
2014-09-19 11:44 ` [tip:sched/core] cpuidle: Use " tip-bot for Chuansheng Liu
2014-09-04 12:53 ` [PATCH 1/3] sched: Add new API wake_up_if_idle() to wake up the idle cpu Daniel Lezcano
2014-09-04 12:59 ` Liu, Chuansheng
2014-09-04 12:59 ` Liu, Chuansheng
2014-09-19 11:43 ` [tip:sched/core] " tip-bot for Chuansheng Liu
2014-12-19 20:23 ` Andy Lutomirski
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