linux-kernel - [PATCH v1 4/9] cpuidle: teo: Drop local variable prev_intercept

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Message-ID: <3327997.aeNJFYEL58@rjwysocki.net>
Date: Mon, 13 Jan 2025 19:40:49 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
 Daniel Lezcano <daniel.lezcano@...aro.org>,
 Christian Loehle <christian.loehle@....com>,
 Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
Subject: [PATCH v1 4/9] cpuidle: teo: Drop local variable prev_intercept_idx

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

Local variable prev_intercept_idx in teo_select() is redundant becase
it cannot be 0 when candidate state index is 0.

The prev_intercept_idx value is the index of the deepest enabled idle
state, so if it is 0, state 0 is the deepest enabled idle state, in
which case it must be the only enabled idle state, but then teo_select()
would have returned early before initializing prev_intercept_idx.

Thus prev_intercept_idx must be nonzero and the check of it against 0
always passes, so it can be dropped altogether.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/cpuidle/governors/teo.c |   15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

--- a/drivers/cpuidle/governors/teo.c
+++ b/drivers/cpuidle/governors/teo.c
@@ -292,7 +292,6 @@
 	unsigned int hit_sum = 0;
 	int constraint_idx = 0;
 	int idx0 = 0, idx = -1;
-	int prev_intercept_idx;
 	s64 duration_ns;
 	int i;

@@ -370,7 +369,6 @@
 	 * all of the deeper states, a shallower idle state is likely to be a
 	 * better choice.
 	 */
-	prev_intercept_idx = idx;
 	if (2 * idx_intercept_sum > cpu_data->total - idx_hit_sum) {
 		int first_suitable_idx = idx;

@@ -437,14 +435,11 @@
 		idx = constraint_idx;

 	if (!idx) {
-		if (prev_intercept_idx) {
-			/*
-			 * Query the sleep length to be able to count the wakeup
-			 * as a hit if it is caused by a timer.
-			 */
-			duration_ns = tick_nohz_get_sleep_length(&delta_tick);
-			cpu_data->sleep_length_ns = duration_ns;
-		}
+		/*
+		 * Query the sleep length to be able to count the wakeup as a
+		 * hit if it is caused by a timer.
+		 */
+		cpu_data->sleep_length_ns = tick_nohz_get_sleep_length(&delta_tick);
 		goto out_tick;
 	}