From: Len Brown <len.brown@xxxxxxxxx>
pm_idle does not scale as an idle handler registration mechanism.
Don't use it for cpuidle. Instead, call cpuidle directly, and
allow architectures to use pm_idle as an arch-specific default
if they need it. ie.
cpu_idle()
...
if(cpuidle_call_idle())
pm_idle();
cc: x86@xxxxxxxxxx
cc: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
---
arch/arm/kernel/process.c | 4 +++-
arch/sh/kernel/idle.c | 6 ++++--
arch/x86/kernel/process_32.c | 4 +++-
arch/x86/kernel/process_64.c | 4 +++-
drivers/cpuidle/cpuidle.c | 39 ++++++++++++++++++---------------------
include/linux/cpuidle.h | 2 ++
6 files changed, 33 insertions(+), 26 deletions(-)
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 5e1e541..d7ee0d4 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -30,6 +30,7 @@
#include <linux/uaccess.h>
#include <linux/random.h>
#include <linux/hw_breakpoint.h>
+#include <linux/cpuidle.h>
#include <asm/cacheflush.h>
#include <asm/leds.h>
@@ -196,7 +197,8 @@ void cpu_idle(void)
cpu_relax();
} else {
stop_critical_timings();
- pm_idle();
+ if (cpuidle_call_idle())
+ pm_idle();
start_critical_timings();
/*
* This will eventually be removed - pm_idle
diff --git a/arch/sh/kernel/idle.c b/arch/sh/kernel/idle.c
index 425d604..9c7099e 100644
--- a/arch/sh/kernel/idle.c
+++ b/arch/sh/kernel/idle.c
@@ -16,12 +16,13 @@
#include <linux/thread_info.h>
#include <linux/irqflags.h>
#include <linux/smp.h>
+#include <linux/cpuidle.h>
#include <asm/pgalloc.h>
#include <asm/system.h>
#include <asm/atomic.h>
#include <asm/smp.h>
-void (*pm_idle)(void) = NULL;
+static void (*pm_idle)(void);
static int hlt_counter;
@@ -100,7 +101,8 @@ void cpu_idle(void)
local_irq_disable();
/* Don't trace irqs off for idle */
stop_critical_timings();
- pm_idle();
+ if (cpuidle_call_idle())
+ pm_idle();
/*
* Sanity check to ensure that pm_idle() returns
* with IRQs enabled
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 8d12878..61fadbe 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -38,6 +38,7 @@
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/kdebug.h>
+#include <linux/cpuidle.h>
#include <asm/pgtable.h>
#include <asm/system.h>
@@ -109,7 +110,8 @@ void cpu_idle(void)
local_irq_disable();
/* Don't trace irqs off for idle */
stop_critical_timings();
- pm_idle();
+ if (cpuidle_idle_call())
+ pm_idle();
start_critical_timings();
}
tick_nohz_restart_sched_tick();
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 6c9dd92..62c219a 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -37,6 +37,7 @@
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/ftrace.h>
+#include <linux/cpuidle.h>
#include <asm/pgtable.h>
#include <asm/system.h>
@@ -136,7 +137,8 @@ void cpu_idle(void)
enter_idle();
/* Don't trace irqs off for idle */
stop_critical_timings();
- pm_idle();
+ if (cpuidle_idle_call())
+ pm_idle();
start_critical_timings();
/* In many cases the interrupt that ended idle
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 8d7303b..304e378 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -25,10 +25,10 @@ DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
DEFINE_MUTEX(cpuidle_lock);
LIST_HEAD(cpuidle_detected_devices);
-static void (*pm_idle_old)(void);
static int enabled_devices;
static int off __read_mostly;
+static int initialized __read_mostly;
int cpuidle_disabled(void)
{
@@ -56,27 +56,24 @@ static int __cpuidle_register_device(struct cpuidle_device *dev);
* cpuidle_idle_call - the main idle loop
*
* NOTE: no locks or semaphores should be used here
+ * return non-zero on failure
*/
-static void cpuidle_idle_call(void)
+int cpuidle_idle_call(void)
{
struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
struct cpuidle_driver *drv = cpuidle_get_driver();
struct cpuidle_state *target_state;
int next_state, entered_state;
- /* check if the device is ready */
- if (!dev || !dev->enabled) {
- if (pm_idle_old)
- pm_idle_old();
- else
-#if defined(CONFIG_ARCH_HAS_DEFAULT_IDLE)
- default_idle();
-#else
- local_irq_enable();
-#endif
- return;
- }
+ if (off)
+ return -ENODEV;
+
+ if (!initialized)
+ return -ENODEV;
+ /* check if the device is ready */
+ if (!dev || !dev->enabled)
+ return -EBUSY;
#if 0
/* shows regressions, re-enable for 2.6.29 */
/*
@@ -90,7 +87,7 @@ static void cpuidle_idle_call(void)
next_state = cpuidle_curr_governor->select(drv, dev);
if (need_resched()) {
local_irq_enable();
- return;
+ return 0;
}
target_state = &drv->states[next_state];
@@ -116,6 +113,8 @@ static void cpuidle_idle_call(void)
/* give the governor an opportunity to reflect on the outcome */
if (cpuidle_curr_governor->reflect)
cpuidle_curr_governor->reflect(dev, entered_state);
+
+ return 0;
}
/**
@@ -123,10 +122,10 @@ static void cpuidle_idle_call(void)
*/
void cpuidle_install_idle_handler(void)
{
- if (enabled_devices && (pm_idle != cpuidle_idle_call)) {
+ if (enabled_devices) {
/* Make sure all changes finished before we switch to new idle */
smp_wmb();
- pm_idle = cpuidle_idle_call;
+ initialized = 1;
}
}
@@ -135,8 +134,8 @@ void cpuidle_install_idle_handler(void)
*/
void cpuidle_uninstall_idle_handler(void)
{
- if (enabled_devices && pm_idle_old && (pm_idle != pm_idle_old)) {
- pm_idle = pm_idle_old;
+ if (enabled_devices) {
+ initialized = 0;
cpuidle_kick_cpus();
}
}
@@ -410,8 +409,6 @@ static int __init cpuidle_init(void)
if (cpuidle_disabled())
return -ENODEV;
- pm_idle_old = pm_idle;
-
ret = cpuidle_add_class_sysfs(&cpu_sysdev_class);
if (ret)
return ret;
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 2786787..c904188 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -128,6 +128,7 @@ struct cpuidle_driver {
#ifdef CONFIG_CPU_IDLE
extern void disable_cpuidle(void);
+extern int cpuidle_idle_call(void);
extern int cpuidle_register_driver(struct cpuidle_driver *drv);
struct cpuidle_driver *cpuidle_get_driver(void);
@@ -142,6 +143,7 @@ extern void cpuidle_disable_device(struct cpuidle_device *dev);
#else
static inline void disable_cpuidle(void) { }
+static inline int cpuidle_idle_call(void) { return -ENODEV; }
static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
{return -ENODEV; }
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