| Message ID | 1455310238-8963-5-git-send-email-lina.iyer@linaro.org (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
On 02/12, Lina Iyer wrote: > @@ -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. > + > /* > * 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? > + 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?
On Fri, Feb 26 2016 at 11:24 -0700, Stephen Boyd wrote: >On 02/12, Lina Iyer wrote: >> @@ -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. > OK. >> + >> /* >> * 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? > OK >> + 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. > OK >> + 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? > True. Will remove. > + >> /* >> * 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? > I did this so we dont even register a hotplug notifier. Will change. Thanks, Lina -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c index 545069d..bf7a80c 100644 --- a/drivers/cpuidle/cpuidle-arm.c +++ b/drivers/cpuidle/cpuidle-arm.c @@ -11,12 +11,14 @@ #define pr_fmt(fmt) "CPUidle arm: " fmt +#include <linux/cpu.h> #include <linux/cpuidle.h> #include <linux/cpumask.h> #include <linux/cpu_pm.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of.h> +#include <linux/pm_runtime.h> #include <linux/slab.h> #include <asm/cpuidle.h> @@ -37,6 +39,7 @@ static int arm_enter_idle_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, int idx) { int ret; + struct device *cpu_dev = get_cpu_device(dev->cpu); if (!idx) { cpu_do_idle(); @@ -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)); + /* * 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, + unsigned long action, void *data) +{ + struct device *cpu_dev = get_cpu_device(smp_processor_id()); + + /* Execute CPU runtime PM on that CPU */ + switch (action) { + case CPU_DYING: + case CPU_DYING_FROZEN: + RCU_NONIDLE(pm_runtime_put_sync_suspend(cpu_dev)); + 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. @@ -118,6 +149,16 @@ static int __init arm_idle_init(void) * idle states suspend back-end specific data */ for_each_possible_cpu(cpu) { + + /* Initialize Runtime PM for the CPU */ + cpu_dev = get_cpu_device(cpu); + pm_runtime_irq_safe(cpu_dev); + pm_runtime_enable(cpu_dev); + if (cpu_online(cpu)) { + pm_runtime_get_noresume(cpu_dev); + pm_runtime_set_active(cpu_dev); + } + ret = arm_cpuidle_init(cpu); /* @@ -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); +#endif + return 0; out_fail: while (--cpu >= 0) { dev = per_cpu(cpuidle_devices, cpu); + cpu_dev = get_cpu_device(cpu); + __pm_runtime_disable(cpu_dev, false); cpuidle_unregister_device(dev); kfree(dev); }
Notify runtime PM when the CPU is going to be powered off in the idle state. This allows for runtime PM suspend/resume of the CPU as well as its PM domain. We do not call into runtime PM for ARM WFI to keep the default state simple and faster. Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Lina Iyer <lina.iyer@linaro.org> --- Changes since RFC v1 - - runtime PM initialization is now done as part of this file - hotplug and its runtime PM invocation is done here drivers/cpuidle/cpuidle-arm.c | 48 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+)