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>
Reviewed-on: http://android.intel.com:8080/48858
Reviewed-by: Gross, Mark <mark.gross@intel.com>
Reviewed-by: Yang, Fei <fei.yang@intel.com>
Reviewed-by: Kuppuswamy, Sathyanarayanan <sathyanarayanan.kuppuswamy@intel.com>
Tested-by: Ng, Cheon-woei <cheon-woei.ng@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index a3d0dc5..e6e043d 100644 (file)
--- 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();