[patch added to 3.12-stable] x86/idle: Restore trace_cpu_idle to mwait_idle() calls

[Jiri Slaby <jslaby@xxxxxxx>]

From: Jisheng Zhang <jszhang@xxxxxxxxxxx>

This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.

===============

commit e43d0189ac02415fe4487f79fc35e8f147e9ea0d upstream.

Commit b253149b843f ("sched/idle/x86: Restore mwait_idle() to fix boot
hangs, to improve power savings and to improve performance") restores
mwait_idle(), but the trace_cpu_idle related calls are missing. This
causes powertop on my old desktop powered by Intel Core2 E6550 to
report zero wakeups and zero events.

Add them back to restore the proper behaviour.

Fixes: b253149b843f ("sched/idle/x86: Restore mwait_idle() to ...")
Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
Cc: <len.brown@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1440046479-4262-1-git-send-email-jszhang@xxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 arch/x86/kernel/process.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index c5db2a43e730..ef486d90f318 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -428,6 +428,7 @@ static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c)
 static void mwait_idle(void)
 {
 	if (!current_set_polling_and_test()) {
+		trace_cpu_idle_rcuidle(1, smp_processor_id());
 		if (static_cpu_has(X86_FEATURE_CLFLUSH_MONITOR)) {
 			mb();
 			clflush((void *)&current_thread_info()->flags);
@@ -439,6 +440,7 @@ static void mwait_idle(void)
 			__sti_mwait(0, 0);
 		else
 			local_irq_enable();
+		trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
 	} else
 		local_irq_enable();
 	__current_clr_polling();
-- 
2.11.0

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