linux-kernel - [PATCH 3/6] cpuidle: menu: Get rid of first_idx from menu

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Date:   Tue, 02 Oct 2018 23:44:06 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PM <linux-pm@...r.kernel.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>
Subject: [PATCH 3/6] cpuidle: menu: Get rid of first_idx from menu_select()

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Rearrange the code in menu_select() so that the loop over idle states
always starts from 0 and get rid of the first_idx variable.

While at it, add two empty lines to separate conditional statements
one another.

No intentional behavior changes.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/cpuidle/governors/menu.c |   32 ++++++++++++++------------------
 1 file changed, 14 insertions(+), 18 deletions(-)

Index: linux-pm/drivers/cpuidle/governors/menu.c
===================================================================
--- linux-pm.orig/drivers/cpuidle/governors/menu.c
+++ linux-pm/drivers/cpuidle/governors/menu.c
@@ -285,7 +285,6 @@ static int menu_select(struct cpuidle_dr
 	struct menu_device *data = this_cpu_ptr(&menu_devices);
 	int latency_req = cpuidle_governor_latency_req(dev->cpu);
 	int i;
-	int first_idx;
 	int idx;
 	unsigned int interactivity_req;
 	unsigned int expected_interval;
@@ -348,36 +347,33 @@ static int menu_select(struct cpuidle_dr
 			latency_req = interactivity_req;
 	}
 
-	first_idx = 0;
-	if (drv->states[0].flags & CPUIDLE_FLAG_POLLING) {
-		struct cpuidle_state *s = &drv->states[1];
-		unsigned int polling_threshold;
-
-		/*
-		 * Default to a physical idle state, not to busy polling, unless
-		 * a timer is going to trigger really really soon.
-		 */
-		polling_threshold = max_t(unsigned int, 20, s->target_residency);
-		if (data->next_timer_us > polling_threshold &&
-		    latency_req > s->exit_latency && !s->disabled &&
-		    !dev->states_usage[1].disable)
-			first_idx = 1;
-	}
-
 	/*
 	 * Find the idle state with the lowest power while satisfying
 	 * our constraints.
 	 */
 	idx = -1;
-	for (i = first_idx; i < drv->state_count; i++) {
+	for (i = 0; i < drv->state_count; i++) {
 		struct cpuidle_state *s = &drv->states[i];
 		struct cpuidle_state_usage *su = &dev->states_usage[i];
 
 		if (s->disabled || su->disable)
 			continue;
+
 		if (idx == -1)
 			idx = i; /* first enabled state */
+
 		if (s->target_residency > predicted_us) {
+			/*
+			 * Use a physical idle state, not busy polling, unless
+			 * a timer is going to trigger really really soon.
+			 */
+			if ((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) &&
+			    i == idx + 1 && latency_req > s->exit_latency &&
+			    data->next_timer_us > max_t(unsigned int, 20,
+							s->target_residency)) {
+				idx = i;
+				break;
+			}
 			if (predicted_us < TICK_USEC)
 				break;