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 <jacob.jun....@linux.intel.com>
---
drivers/cpuidle/cpuidle.c | 13 ++++++++++++-
include/linux/cpuidle.h | 7 ++++++-
kernel/sched/idle.c | 13 ++++++++-----
3 files changed, 26 insertions(+), 7 deletions(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index c73207a..afc005b 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -97,7 +97,17 @@ static int find_deepest_state(struct cpuidle_driver *drv,
return ret;
}
-#ifdef CONFIG_SUSPEND
+/* 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();
+}
+
/**
* cpuidle_find_deepest_state - Find the deepest available idle state.
* @drv: cpuidle driver for the given CPU.
@@ -109,6 +119,7 @@ int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
return find_deepest_state(drv, dev, UINT_MAX, 0, false);
}
+#ifdef CONFIG_SUSPEND
static void enter_freeze_proper(struct cpuidle_driver *drv,
struct cpuidle_device *dev, int index)
{
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index bb31373..63bf385 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)
+#ifdef 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)
@@ -204,6 +206,9 @@ static inline int cpuidle_find_deepest_state(struct
cpuidle_driver *drv,
static inline int cpuidle_enter_freeze(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
{return -ENODEV; }
+static inline void cpuidle_use_deepest_state(bool enable)
+{
+}
#endif
/* kernel/sched/idle.c */
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 1d8718d..513e4df 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -164,11 +164,14 @@ static void cpuidle_idle_call(void)
* timekeeping to prevent timer interrupts from kicking us out of idle
* until a proper wakeup interrupt happens.
*/
- if (idle_should_freeze()) {
- entered_state = cpuidle_enter_freeze(drv, dev);
- if (entered_state > 0) {
- local_irq_enable();
- goto exit_idle;
+
+ if (idle_should_freeze() || dev->use_deepest_state) {
+ if (idle_should_freeze()) {
+ entered_state = cpuidle_enter_freeze(drv, dev);
+ if (entered_state > 0) {
+ local_irq_enable();
+ goto exit_idle;
+ }
}
next_state = cpuidle_find_deepest_state(drv, dev);
--
1.9.1
