On Thursday, July 05, 2012, Daniel Lezcano wrote:
> When the system is booted with some cpus offline, the idle
> driver is not initialized. When a cpu is set online, the
> acpi code call the intel idle init function. Unfortunately
> this code introduce a dependency between intel_idle and acpi.
>
> This patch is intended to remove this dependency by using the
> notifier of intel_idle. This patch has the benefit of
> encapsulating the intel_idle driver and remove some exported
> functions.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> Acked-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
> Acked-by: Rafael J. Wysocki <rjw@xxxxxxx>
OK, I'm taking this one.
Thanks,
Rafael
> ---
> drivers/acpi/processor_driver.c | 7 ------
> drivers/idle/intel_idle.c | 41 +++++++++++++++++++++++++-------------
> include/linux/cpuidle.h | 7 ------
> 3 files changed, 27 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
> index 13103aeb..7048b97 100644
> --- a/drivers/acpi/processor_driver.c
> +++ b/drivers/acpi/processor_driver.c
> @@ -429,18 +429,11 @@ static int acpi_cpu_soft_notify(struct notifier_block *nfb,
> * Initialize missing things
> */
> if (pr->flags.need_hotplug_init) {
> - struct cpuidle_driver *idle_driver =
> - cpuidle_get_driver();
> -
> printk(KERN_INFO "Will online and init hotplugged "
> "CPU: %d\n", pr->id);
> WARN(acpi_processor_start(pr), "Failed to start CPU:"
> " %d\n", pr->id);
> pr->flags.need_hotplug_init = 0;
> - if (idle_driver && !strcmp(idle_driver->name,
> - "intel_idle")) {
> - intel_idle_cpu_init(pr->id);
> - }
> /* Normal CPU soft online event */
> } else {
> acpi_processor_ppc_has_changed(pr, 0);
> diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
> index d0f59c3..fe95d54 100644
> --- a/drivers/idle/intel_idle.c
> +++ b/drivers/idle/intel_idle.c
> @@ -96,6 +96,7 @@ static const struct idle_cpu *icpu;
> static struct cpuidle_device __percpu *intel_idle_cpuidle_devices;
> static int intel_idle(struct cpuidle_device *dev,
> struct cpuidle_driver *drv, int index);
> +static int intel_idle_cpu_init(int cpu);
>
> static struct cpuidle_state *cpuidle_state_table;
>
> @@ -302,22 +303,35 @@ static void __setup_broadcast_timer(void *arg)
> clockevents_notify(reason, &cpu);
> }
>
> -static int setup_broadcast_cpuhp_notify(struct notifier_block *n,
> - unsigned long action, void *hcpu)
> +static int cpu_hotplug_notify(struct notifier_block *n,
> + unsigned long action, void *hcpu)
> {
> int hotcpu = (unsigned long)hcpu;
> + struct cpuidle_device *dev;
>
> switch (action & 0xf) {
> case CPU_ONLINE:
> - smp_call_function_single(hotcpu, __setup_broadcast_timer,
> - (void *)true, 1);
> +
> + if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
> + smp_call_function_single(hotcpu, __setup_broadcast_timer,
> + (void *)true, 1);
> +
> + /*
> + * Some systems can hotplug a cpu at runtime after
> + * the kernel has booted, we have to initialize the
> + * driver in this case
> + */
> + dev = per_cpu_ptr(intel_idle_cpuidle_devices, hotcpu);
> + if (!dev->registered)
> + intel_idle_cpu_init(hotcpu);
> +
> break;
> }
> return NOTIFY_OK;
> }
>
> -static struct notifier_block setup_broadcast_notifier = {
> - .notifier_call = setup_broadcast_cpuhp_notify,
> +static struct notifier_block cpu_hotplug_notifier = {
> + .notifier_call = cpu_hotplug_notify,
> };
>
> static void auto_demotion_disable(void *dummy)
> @@ -405,10 +419,10 @@ static int intel_idle_probe(void)
>
> if (boot_cpu_has(X86_FEATURE_ARAT)) /* Always Reliable APIC Timer */
> lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
> - else {
> + else
> on_each_cpu(__setup_broadcast_timer, (void *)true, 1);
> - register_cpu_notifier(&setup_broadcast_notifier);
> - }
> +
> + register_cpu_notifier(&cpu_hotplug_notifier);
>
> pr_debug(PREFIX "v" INTEL_IDLE_VERSION
> " model 0x%X\n", boot_cpu_data.x86_model);
> @@ -494,7 +508,7 @@ static int intel_idle_cpuidle_driver_init(void)
> * allocate, initialize, register cpuidle_devices
> * @cpu: cpu/core to initialize
> */
> -int intel_idle_cpu_init(int cpu)
> +static int intel_idle_cpu_init(int cpu)
> {
> int cstate;
> struct cpuidle_device *dev;
> @@ -539,7 +553,6 @@ int intel_idle_cpu_init(int cpu)
>
> return 0;
> }
> -EXPORT_SYMBOL_GPL(intel_idle_cpu_init);
>
> static int __init intel_idle_init(void)
> {
> @@ -581,10 +594,10 @@ static void __exit intel_idle_exit(void)
> intel_idle_cpuidle_devices_uninit();
> cpuidle_unregister_driver(&intel_idle_driver);
>
> - if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE) {
> +
> + if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
> on_each_cpu(__setup_broadcast_timer, (void *)false, 1);
> - unregister_cpu_notifier(&setup_broadcast_notifier);
> - }
> + unregister_cpu_notifier(&cpu_hotplug_notifier);
>
> return;
> }
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index 8684a0d..a6b3f2e 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -207,14 +207,7 @@ struct cpuidle_governor {
> extern int cpuidle_register_governor(struct cpuidle_governor *gov);
> extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
>
> -#ifdef CONFIG_INTEL_IDLE
> -extern int intel_idle_cpu_init(int cpu);
> #else
> -static inline int intel_idle_cpu_init(int cpu) { return -1; }
> -#endif
> -
> -#else
> -static inline int intel_idle_cpu_init(int cpu) { return -1; }
>
> static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
> {return 0;}
>
