[RFC v2 04/12] ARM: cpuidle: Add runtime PM support for CPUs
From: Stephen Boyd <hidden>
Date: 2016-02-26 18:24:21
Also in:
linux-arm-msm, linux-pm
On 02/12, Lina Iyer wrote:
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@@ -45,6 +48,8 @@ static int arm_enter_idle_state(struct cpuidle_device *dev, ret = cpu_pm_enter(); if (!ret) { + RCU_NONIDLE(pm_runtime_put_sync_suspend(cpu_dev));
Can you add a comment on why we need to use RCU_NONIDLE here? It's not super obvious.
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+ /* * Pass idle state index to cpu_suspend which in turn will * call the CPU ops suspend protocol with idle index as a@@ -52,6 +57,7 @@ static int arm_enter_idle_state(struct cpuidle_device *dev, */ arm_cpuidle_suspend(idx); + RCU_NONIDLE(pm_runtime_get_sync(cpu_dev)); cpu_pm_exit(); }@@ -84,6 +90,30 @@ static const struct of_device_id arm_idle_state_match[] __initconst = { { }, }; +#ifdef CONFIG_HOTPLUG_CPU +static int cpu_hotplug(struct notifier_block *nb,
This function is pretty generically named. Maybe something more runtime PM specific or cpu idle specific?
+ unsigned long action, void *data)
+{
+ struct device *cpu_dev = get_cpu_device(smp_processor_id());
+
+ /* Execute CPU runtime PM on that CPU */
+ switch (action) {We could do the & ~CPU_TASKS_FROZEN trick here to save a few cases.
+ case CPU_DYING: + case CPU_DYING_FROZEN: + RCU_NONIDLE(pm_runtime_put_sync_suspend(cpu_dev));
And do we actually need to use it for hotplug path? These notifiers don't run from idle context do they?
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+ break; + case CPU_STARTING: + case CPU_STARTING_FROZEN: + RCU_NONIDLE(pm_runtime_get_sync(cpu_dev)); + break; + default: + break; + } + + return NOTIFY_OK; +} +#endif + /* * arm_idle_init *@@ -96,6 +126,7 @@ static int __init arm_idle_init(void) int cpu, ret; struct cpuidle_driver *drv = &arm_idle_driver; struct cpuidle_device *dev; + struct device *cpu_dev; /* * Initialize idle states data, starting at index 1.@@ -148,10 +189,17 @@ static int __init arm_idle_init(void) } } +#ifdef CONFIG_HOTPLUG_CPU + /* Register for hotplug notifications for runtime PM */ + hotcpu_notifier(cpu_hotplug, 0);
Define an empty cpu_hotplug() function for !CONFIG_HOTPLUG_CPU and then always call this without the ifdef? -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project