Merge tag 'pm-6.18-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:
 "These fix three regressions, two recent ones and one introduced during
  the 6.17 development cycle:

   - Add an exit latency check to the menu cpuidle governor in the case
     when it considers using a real idle state instead of a polling one
     to address a performance regression (Rafael Wysocki)

   - Revert an attempted cleanup of a system suspend code path that
     introduced a regression elsewhere (Samuel Wu)

   - Allow pm_restrict_gfp_mask() to be called multiple times in a row
     and adjust pm_restore_gfp_mask() accordingly to avoid having to
     play nasty games with these calls during hibernation (Rafael
     Wysocki)"

* tag 'pm-6.18-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM: sleep: Allow pm_restrict_gfp_mask() stacking
  cpuidle: governors: menu: Select polling state in some more cases
  Revert "PM: sleep: Make pm_wakeup_clear() call more clear"

Author: torvalds

drivers/cpuidle/governors/menu.c

@@ -318,10 +318,13 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
 
 		/*
 		 * Use a physical idle state, not busy polling, unless a timer
-		 * is going to trigger soon enough.
+		 * is going to trigger soon enough or the exit latency of the
+		 * idle state in question is greater than the predicted idle
+		 * duration.
 		 */
 		if ((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) &&
-		    s->target_residency_ns <= data->next_timer_ns) {
+		    s->target_residency_ns <= data->next_timer_ns &&
+		    s->exit_latency_ns <= predicted_ns) {
 			predicted_ns = s->target_residency_ns;
 			idx = i;
 			break;

kernel/power/hibernate.c

@@ -706,7 +706,6 @@ static void power_down(void)
 
 #ifdef CONFIG_SUSPEND
 	if (hibernation_mode == HIBERNATION_SUSPEND) {
-		pm_restore_gfp_mask();
 		error = suspend_devices_and_enter(mem_sleep_current);
 		if (!error)
 			goto exit;
@@ -746,9 +745,6 @@ static void power_down(void)
 		cpu_relax();
 
 exit:
-	/* Match the pm_restore_gfp_mask() call in hibernate(). */
-	pm_restrict_gfp_mask();
-
 	/* Restore swap signature. */
 	error = swsusp_unmark();
 	if (error)

kernel/power/main.c

@@ -31,23 +31,35 @@
  * held, unless the suspend/hibernate code is guaranteed not to run in parallel
  * with that modification).
  */
+static unsigned int saved_gfp_count;
 static gfp_t saved_gfp_mask;
 
 void pm_restore_gfp_mask(void)
 {
 	WARN_ON(!mutex_is_locked(&system_transition_mutex));
-	if (saved_gfp_mask) {
-		gfp_allowed_mask = saved_gfp_mask;
-		saved_gfp_mask = 0;
-	}
+
+	if (WARN_ON(!saved_gfp_count) || --saved_gfp_count)
+		return;
+
+	gfp_allowed_mask = saved_gfp_mask;
+	saved_gfp_mask = 0;
+
+	pm_pr_dbg("GFP mask restored\n");
 }
 
 void pm_restrict_gfp_mask(void)
 {
 	WARN_ON(!mutex_is_locked(&system_transition_mutex));
-	WARN_ON(saved_gfp_mask);
+
+	if (saved_gfp_count++) {
+		WARN_ON((saved_gfp_mask & ~(__GFP_IO | __GFP_FS)) != gfp_allowed_mask);
+		return;
+	}
+
 	saved_gfp_mask = gfp_allowed_mask;
 	gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
+
+	pm_pr_dbg("GFP mask restricted\n");
 }
 
 unsigned int lock_system_sleep(void)

kernel/power/process.c

@@ -132,6 +132,7 @@ int freeze_processes(void)
 	if (!pm_freezing)
 		static_branch_inc(&freezer_active);
 
+	pm_wakeup_clear(0);
 	pm_freezing = true;
 	error = try_to_freeze_tasks(true);
 	if (!error)

kernel/power/suspend.c

@@ -595,7 +595,6 @@ static int enter_state(suspend_state_t state)
 	}
 
 	pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
-	pm_wakeup_clear(0);
 	pm_suspend_clear_flags();
 	error = suspend_prepare(state);
 	if (error)