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x86: simplify idle selection

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default_idle is selected in cpu_idle(), when no other idle routine is
selected. Select it in select_idle_routine() when mwait is not
selected.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Thomas Gleixner 2008-06-09 16:59:53 +02:00 committed by Ingo Molnar
parent 9e26d84273
commit 6ddd2a2794
3 changed files with 10 additions and 22 deletions
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18
arch/x86/kernel/process.c
View File

@ -139,27 +139,23 @@ static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c)
void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
{
static int selected;
if (selected)
return;
#ifdef CONFIG_X86_SMP
if (pm_idle == poll_idle && smp_num_siblings > 1) {
printk(KERN_WARNING "WARNING: polling idle and HT enabled,"
" performance may degrade.\n");
}
#endif
if (pm_idle)
return;
if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
/*
* Skip, if setup has overridden idle.
* One CPU supports mwait => All CPUs supports mwait
*/
if (!pm_idle) {
printk(KERN_INFO "using mwait in idle threads.\n");
pm_idle = mwait_idle;
}
}
selected = 1;
printk(KERN_INFO "using mwait in idle threads.\n");
pm_idle = mwait_idle;
} else
pm_idle = default_idle;
}
static int __init idle_setup(char *str)

7
arch/x86/kernel/process_32.c
View File

@ -168,24 +168,19 @@ void cpu_idle(void)
while (1) {
tick_nohz_stop_sched_tick();
while (!need_resched()) {
void (*idle)(void);
check_pgt_cache();
rmb();
idle = pm_idle;
if (rcu_pending(cpu))
rcu_check_callbacks(cpu, 0);
if (!idle)
idle = default_idle;
if (cpu_is_offline(cpu))
play_dead();
local_irq_disable();
__get_cpu_var(irq_stat).idle_timestamp = jiffies;
idle();
pm_idle();
}
tick_nohz_restart_sched_tick();
preempt_enable_no_resched();

7
arch/x86/kernel/process_64.c
View File

@ -150,12 +150,9 @@ void cpu_idle(void)
while (1) {
tick_nohz_stop_sched_tick();
while (!need_resched()) {
void (*idle)(void);
rmb();
idle = pm_idle;
if (!idle)
idle = default_idle;
if (cpu_is_offline(smp_processor_id()))
play_dead();
/*
@ -165,7 +162,7 @@ void cpu_idle(void)
*/
local_irq_disable();
enter_idle();
idle();
pm_idle();
/* In many cases the interrupt that ended idle
has already called exit_idle. But some idle
loops can be woken up without interrupt. */