x86_64: prepare idle loop for dynamic ticks

Add tick_nohz_{stop,restart}_sched_tick to idle loop in prepartion for turning
on dynticks.  These are just noops until NO_HZ is enabled.

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 98956555450beff2c49d22eed79a63aecff87175..6f9dbbe65eef7c109e9d986dfca3bdda69072e9e 100644 (file)
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -38,6 +38,7 @@
 #include <linux/notifier.h>
 #include <linux/kprobes.h>
 #include <linux/kdebug.h>
+#include <linux/tick.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -208,6 +209,8 @@ void cpu_idle (void)
                        if (__get_cpu_var(cpu_idle_state))
                                __get_cpu_var(cpu_idle_state) = 0;
 
+                       tick_nohz_stop_sched_tick();
+
                        rmb();
                        idle = pm_idle;
                        if (!idle)
@@ -228,6 +231,7 @@ void cpu_idle (void)
                        __exit_idle();
                }
 
+               tick_nohz_restart_sched_tick();
                preempt_enable_no_resched();
                schedule();
                preempt_disable();