Merge tag 'v4.0-rc2' into irq/core, to refresh the tree before applying new changes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 18 insertions, 1 deletions

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index c47fce75e666..94b2d7b88a27 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -7,6 +7,7 @@
 #include <linux/tick.h>
 #include <linux/mm.h>
 #include <linux/stackprotector.h>
+#include <linux/suspend.h>
 
 #include <asm/tlb.h>
 
@@ -47,7 +48,8 @@ static inline int cpu_idle_poll(void)
 	rcu_idle_enter();
 	trace_cpu_idle_rcuidle(0, smp_processor_id());
 	local_irq_enable();
-	while (!tif_need_resched())
+	while (!tif_need_resched() &&
+		(cpu_idle_force_poll || tick_check_broadcast_expired()))
 		cpu_relax();
 	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
 	rcu_idle_exit();
@@ -104,6 +106,21 @@ static void cpuidle_idle_call(void)
 	rcu_idle_enter();
 
 	/*
+	 * Suspend-to-idle ("freeze") is a system state in which all user space
+	 * has been frozen, all I/O devices have been suspended and the only
+	 * activity happens here and in iterrupts (if any).  In that case bypass
+	 * the cpuidle governor and go stratight for the deepest idle state
+	 * available.  Possibly also suspend the local tick and the entire
+	 * timekeeping to prevent timer interrupts from kicking us out of idle
+	 * until a proper wakeup interrupt happens.
+	 */
+	if (idle_should_freeze()) {
+		cpuidle_enter_freeze();
+		local_irq_enable();
+		goto exit_idle;
+	}
+
+	/*
 	 * Ask the cpuidle framework to choose a convenient idle state.
 	 * Fall back to the default arch idle method on errors.
 	 */