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Date: Thu, 26 Sep 2013 00:22:47 +0200
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: Viresh Kumar <viresh.kumar@...aro.org>, rjw@...k.pl
CC: linaro-kernel@...ts.linaro.org, patches@...aro.org,
linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 18/21] cpuidle: don't call poll_idle_init() for every
cpu
On 09/22/2013 03:21 AM, Viresh Kumar wrote:
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
The optimization sounds good but IMHO if we can move this state out of
the cpuidle common framework that would be nicer.
The poll_idle is only applicable for x86 (acpi_driver and intel_idle),
hence I suggest we move this state to these drivers, that will cleanup
the framework code and will remove index shift macro
CPUIDLE_DRIVER_STATE_START which IMHO is weid and prone-to-error.
> ---
> drivers/cpuidle/cpuidle.c | 41 -----------------------------------------
> drivers/cpuidle/driver.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 42 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index 43d5836..bf80236 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -226,45 +226,6 @@ void cpuidle_resume(void)
> mutex_unlock(&cpuidle_lock);
> }
>
> -#ifdef CONFIG_ARCH_HAS_CPU_RELAX
> -static int poll_idle(struct cpuidle_device *dev,
> - struct cpuidle_driver *drv, int index)
> -{
> - ktime_t t1, t2;
> - s64 diff;
> -
> - t1 = ktime_get();
> - local_irq_enable();
> - while (!need_resched())
> - cpu_relax();
> -
> - t2 = ktime_get();
> - diff = ktime_to_us(ktime_sub(t2, t1));
> - if (diff > INT_MAX)
> - diff = INT_MAX;
> -
> - dev->last_residency = (int) diff;
> -
> - return index;
> -}
> -
> -static void poll_idle_init(struct cpuidle_driver *drv)
> -{
> - struct cpuidle_state *state = &drv->states[0];
> -
> - snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
> - snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
> - state->exit_latency = 0;
> - state->target_residency = 0;
> - state->power_usage = -1;
> - state->flags = 0;
> - state->enter = poll_idle;
> - state->disabled = false;
> -}
> -#else
> -static void poll_idle_init(struct cpuidle_driver *drv) {}
> -#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
> -
> /**
> * cpuidle_enable_device - enables idle PM for a CPU
> * @dev: the CPU
> @@ -294,8 +255,6 @@ int cpuidle_enable_device(struct cpuidle_device *dev)
> if (!dev->state_count)
> dev->state_count = drv->state_count;
>
> - poll_idle_init(drv);
> -
> ret = cpuidle_add_device_sysfs(dev);
> if (ret)
> return ret;
> diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
> index 7b2510a..a4a93b4 100644
> --- a/drivers/cpuidle/driver.c
> +++ b/drivers/cpuidle/driver.c
> @@ -10,6 +10,7 @@
>
> #include <linux/mutex.h>
> #include <linux/module.h>
> +#include <linux/sched.h>
> #include <linux/cpuidle.h>
> #include <linux/cpumask.h>
> #include <linux/clockchips.h>
> @@ -179,6 +180,45 @@ static void __cpuidle_driver_init(struct cpuidle_driver *drv)
> }
> }
>
> +#ifdef CONFIG_ARCH_HAS_CPU_RELAX
> +static int poll_idle(struct cpuidle_device *dev,
> + struct cpuidle_driver *drv, int index)
> +{
> + ktime_t t1, t2;
> + s64 diff;
> +
> + t1 = ktime_get();
> + local_irq_enable();
> + while (!need_resched())
> + cpu_relax();
> +
> + t2 = ktime_get();
> + diff = ktime_to_us(ktime_sub(t2, t1));
> + if (diff > INT_MAX)
> + diff = INT_MAX;
> +
> + dev->last_residency = (int) diff;
> +
> + return index;
> +}
> +
> +static void poll_idle_init(struct cpuidle_driver *drv)
> +{
> + struct cpuidle_state *state = &drv->states[0];
> +
> + snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
> + snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
> + state->exit_latency = 0;
> + state->target_residency = 0;
> + state->power_usage = -1;
> + state->flags = 0;
> + state->enter = poll_idle;
> + state->disabled = false;
> +}
> +#else
> +static void poll_idle_init(struct cpuidle_driver *drv) {}
> +#endif /* !CONFIG_ARCH_HAS_CPU_RELAX */
> +
> /**
> * __cpuidle_register_driver: register the driver
> * @drv: a valid pointer to a struct cpuidle_driver
> @@ -212,6 +252,8 @@ static int __cpuidle_register_driver(struct cpuidle_driver *drv)
> on_each_cpu_mask(drv->cpumask, cpuidle_setup_broadcast_timer,
> (void *)CLOCK_EVT_NOTIFY_BROADCAST_ON, 1);
>
> + poll_idle_init(drv);
> +
> return 0;
> }
>
>
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