x86: simplify idle selection

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>

3 files changed, 10 insertions, 22 deletions

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index ba370dc8685b..b3078f4ce25b 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -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)
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index f8476dfbb60d..ee4ab461c50d 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -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();
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index e2319f39988b..db3d89a04399 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -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. */