[PATCH 1/3] sched / idle: Call idle_set_state() from cpuidle_enter_state()

From: Rafael J. Wysocki
Date: Sat May 09 2015 - 18:55:53 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Introduce a wrapper function around idle_set_state() called
sched_idle_set_state() that will pass this_rq() to it as the
first argument and make cpuidle_enter_state() call the new
function before and after entering the target state.

At the same time, remove direct invocations of idle_set_state()
from call_cpuidle().

This will allow the invocation of default_idle_call() to be
moved from call_cpuidle() to cpuidle_enter_state() safely
and call_cpuidle() to be simplified a bit as a result.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/cpuidle/cpuidle.c | 6 ++++++
include/linux/cpuidle.h | 3 +++
kernel/sched/idle.c | 15 +++++++++------
3 files changed, 18 insertions(+), 6 deletions(-)

Index: linux-pm/kernel/sched/idle.c
===================================================================
--- linux-pm.orig/kernel/sched/idle.c
+++ linux-pm/kernel/sched/idle.c
@@ -15,6 +15,15 @@

#include "sched.h"

+/**
+ * sched_idle_set_state - Record idle state for the current CPU.
+ * @idle_state: State to record.
+ */
+void sched_idle_set_state(struct cpuidle_state *idle_state)
+{
+ idle_set_state(this_rq(), idle_state);
+}
+
static int __read_mostly cpu_idle_force_poll;

void cpu_idle_poll_ctrl(bool enable)
@@ -100,9 +109,6 @@ static int call_cpuidle(struct cpuidle_d
return -EBUSY;
}

- /* Take note of the planned idle state. */
- idle_set_state(this_rq(), &drv->states[next_state]);
-
/*
* Enter the idle state previously returned by the governor decision.
* This function will block until an interrupt occurs and will take
@@ -110,9 +116,6 @@ static int call_cpuidle(struct cpuidle_d
*/
entered_state = cpuidle_enter(drv, dev, next_state);

- /* The cpu is no longer idle or about to enter idle. */
- idle_set_state(this_rq(), NULL);
-
if (entered_state == -EBUSY)
default_idle_call();

Index: linux-pm/drivers/cpuidle/cpuidle.c
===================================================================
--- linux-pm.orig/drivers/cpuidle/cpuidle.c
+++ linux-pm/drivers/cpuidle/cpuidle.c
@@ -170,6 +170,9 @@ int cpuidle_enter_state(struct cpuidle_d
if (broadcast && tick_broadcast_enter())
return -EBUSY;

+ /* Take note of the planned idle state. */
+ sched_idle_set_state(target_state);
+
trace_cpu_idle_rcuidle(index, dev->cpu);
time_start = ktime_get();

@@ -178,6 +181,9 @@ int cpuidle_enter_state(struct cpuidle_d
time_end = ktime_get();
trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);

+ /* The cpu is no longer idle or about to enter idle. */
+ sched_idle_set_state(NULL);
+
if (broadcast) {
if (WARN_ON_ONCE(!irqs_disabled()))
local_irq_disable();
Index: linux-pm/include/linux/cpuidle.h
===================================================================
--- linux-pm.orig/include/linux/cpuidle.h
+++ linux-pm/include/linux/cpuidle.h
@@ -200,6 +200,9 @@ static inline struct cpuidle_driver *cpu
struct cpuidle_device *dev) {return NULL; }
#endif

+/* kernel/sched/idle.c */
+extern void sched_idle_set_state(struct cpuidle_state *idle_state);
+
#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
#else
--
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