Merge tag 'pm-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more power management updates from Rafael Wysocki:
 "These remove a questionable heuristic from the menu cpuidle governor,
  fix a recent build regression in the intel_pstate driver, clean up ARM
  big-Little support in cpufreq and fix up hung task watchdog's
  interaction with system-wide power management transitions.

  Specifics:

   - Fix build regression in the intel_pstate driver that doesn't build
     without CONFIG_ACPI after recent changes (Dominik Brodowski).

   - One of the heuristics in the menu cpuidle governor is based on a
     function returning 0 most of the time, so drop it and clean up the
     scheduler code related to it (Daniel Lezcano).

   - Prevent the arm_big_little cpufreq driver from being used on ARM64
     which is not suitable for it and drop the arm_big_little_dt driver
     that is not used any more (Sudeep Holla).

   - Prevent the hung task watchdog from triggering during resume from
     system-wide sleep states by disabling it before freezing tasks and
     enabling it again after they have been thawed (Vitaly Kuznetsov)"

* tag 'pm-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  kernel: hung_task.c: disable on suspend
  cpufreq: remove unused arm_big_little_dt driver
  cpufreq: drop ARM_BIG_LITTLE_CPUFREQ support for ARM64
  cpufreq: intel_pstate: Fix compilation for !CONFIG_ACPI
  cpuidle: menu: Remove get_loadavg() from the performance multiplier
  sched: Factor out nr_iowait and nr_iowait_cpu

1 files changed, 29 insertions, 1 deletions

diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index b9132d1269ef..cb8e3e8ac7b9 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -15,6 +15,7 @@
 #include <linux/lockdep.h>
 #include <linux/export.h>
 #include <linux/sysctl.h>
+#include <linux/suspend.h>
 #include <linux/utsname.h>
 #include <linux/sched/signal.h>
 #include <linux/sched/debug.h>
@@ -242,6 +243,28 @@ void reset_hung_task_detector(void)
 }
 EXPORT_SYMBOL_GPL(reset_hung_task_detector);
 
+static bool hung_detector_suspended;
+
+static int hungtask_pm_notify(struct notifier_block *self,
+			      unsigned long action, void *hcpu)
+{
+	switch (action) {
+	case PM_SUSPEND_PREPARE:
+	case PM_HIBERNATION_PREPARE:
+	case PM_RESTORE_PREPARE:
+		hung_detector_suspended = true;
+		break;
+	case PM_POST_SUSPEND:
+	case PM_POST_HIBERNATION:
+	case PM_POST_RESTORE:
+		hung_detector_suspended = false;
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
 /*
  * kthread which checks for tasks stuck in D state
  */
@@ -261,7 +284,8 @@ static int watchdog(void *dummy)
 		interval = min_t(unsigned long, interval, timeout);
 		t = hung_timeout_jiffies(hung_last_checked, interval);
 		if (t <= 0) {
-			if (!atomic_xchg(&reset_hung_task, 0))
+			if (!atomic_xchg(&reset_hung_task, 0) &&
+			    !hung_detector_suspended)
 				check_hung_uninterruptible_tasks(timeout);
 			hung_last_checked = jiffies;
 			continue;
@@ -275,6 +299,10 @@ static int watchdog(void *dummy)
 static int __init hung_task_init(void)
 {
 	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+
+	/* Disable hung task detector on suspend */
+	pm_notifier(hungtask_pm_notify, 0);
+
 	watchdog_task = kthread_run(watchdog, NULL, "khungtaskd");
 
 	return 0;