When idle injection is used to cap power, we need to override governor's choice of idle states. This patch allows caller to select the deepest idle state on a CPU therefore achieve the maximum potential power saving.
Signed-off-by: Jacob Pan <[email protected]> --- drivers/cpuidle/cpuidle.c | 12 ++++++++++++ include/linux/cpuidle.h | 4 +++- kernel/sched/idle.c | 3 +++ 3 files changed, 18 insertions(+), 1 deletion(-) diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index c73207a..9ad45b3 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -97,6 +97,18 @@ static int find_deepest_state(struct cpuidle_driver *drv, return ret; } +/* Set the current cpu to use the deepest idle state, override governors */ +void cpuidle_use_deepest_state(bool enable) +{ + struct cpuidle_device *dev; + + preempt_disable(); + dev = cpuidle_get_device(); + dev->use_deepest_state = enable; + preempt_enable(); +} +EXPORT_SYMBOL_GPL(cpuidle_use_deepest_state); + #ifdef CONFIG_SUSPEND /** * cpuidle_find_deepest_state - Find the deepest available idle state. diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index bb31373..7f93c63 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -74,6 +74,7 @@ struct cpuidle_state { struct cpuidle_device { unsigned int registered:1; unsigned int enabled:1; + unsigned int use_deepest_state:1; unsigned int cpu; int last_residency; @@ -192,11 +193,12 @@ static inline struct cpuidle_driver *cpuidle_get_cpu_driver( static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; } #endif -#if defined(CONFIG_CPU_IDLE) && defined(CONFIG_SUSPEND) +#if defined(CONFIG_CPU_IDLE) extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv, struct cpuidle_device *dev); extern int cpuidle_enter_freeze(struct cpuidle_driver *drv, struct cpuidle_device *dev); +extern void cpuidle_use_deepest_state(bool enable); #else static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv, struct cpuidle_device *dev) diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index ffd9a83..fc65147 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -173,6 +173,9 @@ static void cpuidle_idle_call(void) next_state = cpuidle_find_deepest_state(drv, dev); call_cpuidle(drv, dev, next_state); + } else if (dev->use_deepest_state) { + next_state = cpuidle_find_deepest_state(drv, dev); + call_cpuidle(drv, dev, next_state); } else { /* * Ask the cpuidle framework to choose a convenient idle state. -- 1.9.1
