From bc721c1e4517a5110c4b0ae2e80345d3db6425fc Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 6 Feb 2020 18:41:06 +0100 Subject: intel_idle: Clean up definitions of cpuidle callbacks Add proper kerneldoc descriptions to intel_idle() and intel_idle_s2idle(), annotate the latter with __cpuidle and reorder the declarations of local variables in both of them to reflect the mwait_idle_with_hints() arguments order. No intentional functional impact. Signed-off-by: Rafael J. Wysocki --- drivers/idle/intel_idle.c | 39 +++++++++++++++++++++++++++------------ 1 file changed, 27 insertions(+), 12 deletions(-) (limited to 'drivers/idle/intel_idle.c') diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 8d66efc53b89..5adc058c705d 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -892,19 +892,28 @@ static struct cpuidle_state dnv_cstates[] = { }; /** - * intel_idle - * @dev: cpuidle_device - * @drv: cpuidle driver - * @index: index of cpuidle state + * intel_idle - Ask the processor to enter the given idle state. + * @dev: cpuidle device of the target CPU. + * @drv: cpuidle driver (assumed to point to intel_idle_driver). + * @index: Target idle state index. + * + * Use the MWAIT instruction to notify the processor that the CPU represented by + * @dev is idle and it can try to enter the idle state corresponding to @index. + * + * If the local APIC timer is not known to be reliable in the target idle state, + * enable one-shot tick broadcasting for the target CPU before executing MWAIT. + * + * Optionally call leave_mm() for the target CPU upfront to avoid wakeups due to + * flushing user TLBs. * * Must be called under local_irq_disable(). */ static __cpuidle int intel_idle(struct cpuidle_device *dev, struct cpuidle_driver *drv, int index) { - unsigned long ecx = 1; /* break on interrupt flag */ struct cpuidle_state *state = &drv->states[index]; unsigned long eax = flg2MWAIT(state->flags); + unsigned long ecx = 1; /* break on interrupt flag */ bool uninitialized_var(tick); int cpu = smp_processor_id(); @@ -937,16 +946,22 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev, } /** - * intel_idle_s2idle - simplified "enter" callback routine for suspend-to-idle - * @dev: cpuidle_device - * @drv: cpuidle driver - * @index: state index + * intel_idle_s2idle - Ask the processor to enter the given idle state. + * @dev: cpuidle device of the target CPU. + * @drv: cpuidle driver (assumed to point to intel_idle_driver). + * @index: Target idle state index. + * + * Use the MWAIT instruction to notify the processor that the CPU represented by + * @dev is idle and it can try to enter the idle state corresponding to @index. + * + * Invoked as a suspend-to-idle callback routine with frozen user space, frozen + * scheduler tick and suspended scheduler clock on the target CPU. */ -static void intel_idle_s2idle(struct cpuidle_device *dev, - struct cpuidle_driver *drv, int index) +static __cpuidle void intel_idle_s2idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) { - unsigned long ecx = 1; /* break on interrupt flag */ unsigned long eax = flg2MWAIT(drv->states[index].flags); + unsigned long ecx = 1; /* break on interrupt flag */ mwait_idle_with_hints(eax, ecx); } -- cgit v1.2.3