x86: Call idle notifiers

BZ: 35303

Google patched the idle loop for x86-64 (commit 1fd57f722c) and for ARM
(commit 41fa406c26), but they forgot x86-32.

This is preventing their interactive governor from upshifting CPU
frequencies in intel's SOC platforms (e.g. Medfield, etc.).

Fixing that.

NOTE: The notifier calls are not located in the same exact place in the
idle loop for x86-64 and ARM.  The notifier is called inside the
`while(!need_resched)' loop in x86-64 and outside of it in ARM.  Since
Google has likely tuned this governor for ARM, leaving it as in ARM.

Change-Id: Ibefd0c8f08e4b4c24c4a5c32dcdc574f9090b2b9
Signed-off-by: German Monroy <german.monroy@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index fcdb1b3..12dae34 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -98,6 +98,7 @@ void cpu_idle(void)
 	/* endless idle loop with no priority at all */
 	while (1) {
 		tick_nohz_stop_sched_tick(1);
+		idle_notifier_call_chain(IDLE_START);
 		while (!need_resched()) {
 
 			check_pgt_cache();
@@ -112,6 +113,7 @@ void cpu_idle(void)
 			pm_idle();
 			start_critical_timings();
 		}
+		idle_notifier_call_chain(IDLE_END);
 		tick_nohz_restart_sched_tick();
 		preempt_enable_no_resched();
 		schedule();