[patch 23/34] mn10300: Use generic idle loop

Thomas Gleixner
2013-03-21T21:57:53Z

[-- Attachment #1: mn10300-use-generic-idle-loop.patch --]
[-- Type: text/plain, Size: 3358 bytes --]

default_idle() boils down to safe_halt() and the other option is idle
polling. Use the core functionality.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David Howells <dhowells@redhat.com>
---
arch/mn10300/Kconfig | 1
arch/mn10300/kernel/process.c | 70 +++---------------------------------------
arch/mn10300/kernel/smp.c | 2 -
3 files changed, 8 insertions(+), 65 deletions(-)

Index: linux-2.6/arch/mn10300/Kconfig
===================================================================
--- linux-2.6.orig/arch/mn10300/Kconfig
+++ linux-2.6/arch/mn10300/Kconfig
@@ -13,6 +13,7 @@ config MN10300
select MODULES_USE_ELF_RELA
select OLD_SIGSUSPEND3
select OLD_SIGACTION
+ select GENERIC_IDLE_LOOP

config AM33_2
def_bool n
Index: linux-2.6/arch/mn10300/kernel/process.c
===================================================================
--- linux-2.6.orig/arch/mn10300/kernel/process.c
+++ linux-2.6/arch/mn10300/kernel/process.c
@@ -50,77 +50,19 @@ unsigned long thread_saved_pc(struct tas
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);

-#if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
-/*
- * we use this if we don't have any better idle routine
- */
-static void default_idle(void)
-{
- local_irq_disable();
- if (!need_resched())
- safe_halt();
- else
- local_irq_enable();
-}
-
-#else /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
/*
* On SMP it's slightly faster (but much more power-consuming!)
* to poll the ->work.need_resched flag instead of waiting for the
* cross-CPU IPI to arrive. Use this option with caution.
+ *
+ * tglx: No idea why this depends on HOTPLUG_CPU !?!
*/
-static inline void poll_idle(void)
-{
- int oldval;
-
- local_irq_enable();
-
- /*
- * Deal with another CPU just having chosen a thread to
- * run here:
- */
- oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
-
- if (!oldval) {
- set_thread_flag(TIF_POLLING_NRFLAG);
- while (!need_resched())
- cpu_relax();
- clear_thread_flag(TIF_POLLING_NRFLAG);
- } else {
- set_need_resched();
- }
-}
-#endif /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
-
-/*
- * the idle thread
- * - there's no useful work to be done, so just try to conserve power and have
- * a low exit latency (ie sit in a loop waiting for somebody to say that
- * they'd like to reschedule)
- */
-void cpu_idle(void)
+#if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
+void arch_cpu_idle(void)
{
- /* endless idle loop with no priority at all */
- for (;;) {
- rcu_idle_enter();
- while (!need_resched()) {
- void (*idle)(void);
-
- smp_rmb();
- if (!idle) {
-#if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
- idle = poll_idle;
-#else /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
- idle = default_idle;
-#endif /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
- }
- idle();
- }
- rcu_idle_exit();
-
- schedule_preempt_disabled();
- }
+ safe_halt();
}
+#endif

void release_segments(struct mm_struct *mm)
{
Index: linux-2.6/arch/mn10300/kernel/smp.c
===================================================================
--- linux-2.6.orig/arch/mn10300/kernel/smp.c
+++ linux-2.6/arch/mn10300/kernel/smp.c
@@ -675,7 +675,7 @@ int __init start_secondary(void *unused)
#ifdef CONFIG_GENERIC_CLOCKEVENTS
init_clockevents();
#endif
- cpu_idle();
+ cpu_startup_entry(CPUHP_ONLINE);
return 0;
}