diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index 8c7930b5a65fabaa3ae58c8a2224ed056e1fc95f..7e48eb5bf0a7a1aebb958157c38a0d6b1228a437 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -19,11 +19,9 @@ config CPU_IDLE_MULTIPLE_DRIVERS
config CPU_IDLE_GOV_LADDER
bool "Ladder governor (for periodic timer tick)"
- default y
config CPU_IDLE_GOV_MENU
bool "Menu governor (for tickless system)"
- default y
config DT_IDLE_STATES
bool
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 17a6dc0e211110f00ac2e73728414f161d5a194f..046423b0c5ca22aad3455101d3cafae7fc4dda87 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -79,9 +79,9 @@ static int find_deepest_state(struct cpuidle_driver *drv,
bool freeze)
{
unsigned int latency_req = 0;
- int i, ret = -ENXIO;
+ int i, ret = 0;
- for (i = 0; i < drv->state_count; i++) {
+ for (i = 1; i < drv->state_count; i++) {
struct cpuidle_state *s = &drv->states[i];
struct cpuidle_state_usage *su = &dev->states_usage[i];
@@ -243,7 +243,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
* @drv: the cpuidle driver
* @dev: the cpuidle device
*
- * Returns the index of the idle state.
+ * Returns the index of the idle state. The return value must not be negative.
*/
int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
{
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index 401c0106ed345eda469a590aa345f88d8ff59eca..63bd5a403e22f1a5e30cb633998368c60a1b384c 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -17,6 +17,7 @@
#include <linux/pm_qos.h>
#include <linux/module.h>
#include <linux/jiffies.h>
+#include <linux/tick.h>
#include <asm/io.h>
#include <asm/uaccess.h>
@@ -184,6 +185,14 @@ static struct cpuidle_governor ladder_governor = {
*/
static int __init init_ladder(void)
{
+ /*
+ * When NO_HZ is disabled, or when booting with nohz=off, the ladder
+ * governor is better so give it a higher rating than the menu
+ * governor.
+ */
+ if (!tick_nohz_enabled)
+ ladder_governor.rating = 25;
+
return cpuidle_register_governor(&ladder_governor);
}
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 7b0971d97cc331e81ac19681029056fc9cda7cd5..0742b32966739cc3a125acd6f28c7e067dc9cb7b 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -294,8 +294,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
data->needs_update = 0;
}
- data->last_state_idx = CPUIDLE_DRIVER_STATE_START - 1;
-
/* Special case when user has set very strict latency requirement */
if (unlikely(latency_req == 0))
return 0;
@@ -326,20 +324,25 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
if (latency_req > interactivity_req)
latency_req = interactivity_req;
- /*
- * We want to default to C1 (hlt), not to busy polling
- * unless the timer is happening really really soon.
- */
- if (interactivity_req > 20 &&
- !drv->states[CPUIDLE_DRIVER_STATE_START].disabled &&
- dev->states_usage[CPUIDLE_DRIVER_STATE_START].disable == 0)
+ if (CPUIDLE_DRIVER_STATE_START > 0) {
+ data->last_state_idx = CPUIDLE_DRIVER_STATE_START - 1;
+ /*
+ * We want to default to C1 (hlt), not to busy polling
+ * unless the timer is happening really really soon.
+ */
+ if (interactivity_req > 20 &&
+ !drv->states[CPUIDLE_DRIVER_STATE_START].disabled &&
+ dev->states_usage[CPUIDLE_DRIVER_STATE_START].disable == 0)
+ data->last_state_idx = CPUIDLE_DRIVER_STATE_START;
+ } else {
data->last_state_idx = CPUIDLE_DRIVER_STATE_START;
+ }
/*
* Find the idle state with the lowest power while satisfying
* our constraints.
*/
- for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
+ for (i = data->last_state_idx + 1; i < drv->state_count; i++) {
struct cpuidle_state *s = &drv->states[i];
struct cpuidle_state_usage *su = &dev->states_usage[i];
diff --git a/include/linux/tick.h b/include/linux/tick.h
index e312219ff8230bb8a4b8fad60ed4fc0e40a6afd3..97fd4e543846b5f4de1dc5e366f250cc26724098 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -98,6 +98,7 @@ static inline void tick_broadcast_exit(void)
}
#ifdef CONFIG_NO_HZ_COMMON
+extern int tick_nohz_enabled;
extern int tick_nohz_tick_stopped(void);
extern void tick_nohz_idle_enter(void);
extern void tick_nohz_idle_exit(void);
@@ -106,6 +107,7 @@ extern ktime_t tick_nohz_get_sleep_length(void);
extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
#else /* !CONFIG_NO_HZ_COMMON */
+#define tick_nohz_enabled (0)
static inline int tick_nohz_tick_stopped(void) { return 0; }
static inline void tick_nohz_idle_enter(void) { }
static inline void tick_nohz_idle_exit(void) { }
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 4a2ef5a02fd3f91d7c4228378c23d5606bb73812..34852ee70d549848d5793517677c276cdb7e98e5 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -97,12 +97,6 @@ void default_idle_call(void)
static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
int next_state)
{
- /* Fall back to the default arch idle method on errors. */
- if (next_state < 0) {
- default_idle_call();
- return next_state;
- }
-
/*
* The idle task must be scheduled, it is pointless to go to idle, just
* update no idle residency and return.
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 9cc20af58c76300111f23a007b9fd5ad0c8bd60b..9d7a053545f5aca7a324f3530ee52ca9dac413f8 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -387,7 +387,7 @@ void __init tick_nohz_init(void)
/*
* NO HZ enabled ?
*/
-static int tick_nohz_enabled __read_mostly = 1;
+int tick_nohz_enabled __read_mostly = 1;
unsigned long tick_nohz_active __read_mostly;
/*
* Enable / Disable tickless mode