Patch "x86/idle: Restore trace_cpu_idle to mwait_idle() calls" has been added to the 4.1-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    x86/idle: Restore trace_cpu_idle to mwait_idle() calls

to the 4.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     x86-idle-restore-trace_cpu_idle-to-mwait_idle-calls.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From e43d0189ac02415fe4487f79fc35e8f147e9ea0d Mon Sep 17 00:00:00 2001
From: Jisheng Zhang <jszhang@xxxxxxxxxxx>
Date: Thu, 20 Aug 2015 12:54:39 +0800
Subject: x86/idle: Restore trace_cpu_idle to mwait_idle() calls

From: Jisheng Zhang <jszhang@xxxxxxxxxxx>

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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/x86/kernel/process.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -453,6 +453,7 @@ static int prefer_mwait_c1_over_halt(con
 static void mwait_idle(void)
 {
 	if (!current_set_polling_and_test()) {
+		trace_cpu_idle_rcuidle(1, smp_processor_id());
 		if (this_cpu_has(X86_BUG_CLFLUSH_MONITOR)) {
 			smp_mb(); /* quirk */
 			clflush((void *)&current_thread_info()->flags);
@@ -464,6 +465,7 @@ 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();
 	}


Patches currently in stable-queue which might be from jszhang@xxxxxxxxxxx are

queue-4.1/x86-idle-restore-trace_cpu_idle-to-mwait_idle-calls.patch
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