[RFC PATCH 04/20] Idle notifier standardization x86_32

Mathieu Desnoyers
2010-08-17T23:23:28Z

[-- Attachment #1: idle-notifier-x86_32.patch --]
[-- Type: text/plain, Size: 3333 bytes --]

Add idle notifier callback to x86_32.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
arch/x86/include/asm/idle.h | 5 -----
arch/x86/kernel/apm_32.c | 6 ++++++
arch/x86/kernel/process_32.c | 33 +++++++++++++++++++++++++++++++++
3 files changed, 39 insertions(+), 5 deletions(-)

Index: linux.trees.git/arch/x86/kernel/process_32.c
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/process_32.c 2010-06-19 16:09:48.000000000 -0400
+++ linux.trees.git/arch/x86/kernel/process_32.c 2010-06-19 16:16:53.000000000 -0400
@@ -38,6 +38,8 @@
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/kdebug.h>
+#include <linux/notifier.h>
+#include <linux/idle.h>

#include <asm/pgtable.h>
#include <asm/system.h>
@@ -61,6 +63,30 @@

asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");

+static DEFINE_PER_CPU(unsigned char, is_idle);
+
+void enter_idle(void)
+{
+ percpu_write(is_idle, 1);
+ notify_idle(IDLE_START);
+}
+
+static void __exit_idle(void)
+{
+ if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
+ return;
+ notify_idle(IDLE_END);
+}
+
+/* Called from interrupts to signify idle end */
+void exit_idle(void)
+{
+ /* idle loop has pid 0 */
+ if (current->pid)
+ return;
+ __exit_idle();
+}
+
/*
* Return saved PC of a blocked thread.
*/
@@ -109,10 +135,17 @@ void cpu_idle(void)
play_dead();

local_irq_disable();
+ enter_idle();
/* Don't trace irqs off for idle */
stop_critical_timings();
pm_idle();
start_critical_timings();
+ /*
+ * In many cases the interrupt that ended idle
+ * has already called exit_idle. But some idle loops can
+ * be woken up without interrupt.
+ */
+ __exit_idle();

trace_power_end(smp_processor_id());
}
Index: linux.trees.git/arch/x86/include/asm/idle.h
===================================================================
--- linux.trees.git.orig/arch/x86/include/asm/idle.h 2010-06-19 16:15:29.000000000 -0400
+++ linux.trees.git/arch/x86/include/asm/idle.h 2010-06-19 16:15:34.000000000 -0400
@@ -1,13 +1,8 @@
#ifndef _ASM_X86_IDLE_H
#define _ASM_X86_IDLE_H

-#ifdef CONFIG_X86_64
void enter_idle(void);
void exit_idle(void);
-#else /* !CONFIG_X86_64 */
-static inline void enter_idle(void) { }
-static inline void exit_idle(void) { }
-#endif /* CONFIG_X86_64 */

void c1e_remove_cpu(int cpu);

Index: linux.trees.git/arch/x86/kernel/apm_32.c
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/apm_32.c 2010-06-19 16:08:32.000000000 -0400
+++ linux.trees.git/arch/x86/kernel/apm_32.c 2010-06-19 16:15:34.000000000 -0400
@@ -227,6 +227,7 @@
#include <linux/suspend.h>
#include <linux/kthread.h>
#include <linux/jiffies.h>
+#include <linux/idle.h>

#include <asm/system.h>
#include <asm/uaccess.h>
@@ -947,10 +948,15 @@ recalc:
break;
}
}
+ enter_idle();
if (original_pm_idle)
original_pm_idle();
else
default_idle();
+ /* In many cases the interrupt that ended idle
+ has already called exit_idle. But some idle
+ loops can be woken up without interrupt. */
+ __exit_idle();
local_irq_disable();
jiffies_since_last_check = jiffies - last_jiffies;
if (jiffies_since_last_check > idle_period)