linux-kernel - [PATCH v1 1/4] cpuidle: governors: teo: Drop incorrect target residency check

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Message-ID: <5035693.GXAFRqVoOG@rafael.j.wysocki>
Date: Wed, 12 Nov 2025 17:22:30 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Linux PM <linux-pm@...r.kernel.org>,
 Christian Loehle <christian.loehle@....com>
Cc: LKML <linux-kernel@...r.kernel.org>, Reka Norman <rekanorman@...omium.org>
Subject:
 [PATCH v1 1/4] cpuidle: governors: teo: Drop incorrect target residency check

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

When the target residency of the current candidate idle state is
greater than the expected time till the closest timer (the sleep
length), it does not matter whether or not the tick has already
been stopped or if it is going to be stopped.  The closest timer
will trigger anyway at its due time, so it does not make sense to
select an idle state with target residency above the sleep length.

Accordingly, drop the teo_state_ok() check done in that case and
let the governor use the teo_find_shallower_state() return value
as the new candidate idle state index.

Fixes: 21d28cd2fa5f ("cpuidle: teo: Do not call tick_nohz_get_sleep_length() upfront")
Cc: All applicable <stable@...r.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/cpuidle/governors/teo.c |    7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

--- a/drivers/cpuidle/governors/teo.c
+++ b/drivers/cpuidle/governors/teo.c
@@ -458,11 +458,8 @@ static int teo_select(struct cpuidle_dri
 	 * If the closest expected timer is before the target residency of the
 	 * candidate state, a shallower one needs to be found.
 	 */
-	if (drv->states[idx].target_residency_ns > duration_ns) {
-		i = teo_find_shallower_state(drv, dev, idx, duration_ns, false);
-		if (teo_state_ok(i, drv))
-			idx = i;
-	}
+	if (drv->states[idx].target_residency_ns > duration_ns)
+		idx = teo_find_shallower_state(drv, dev, idx, duration_ns, false);

 	/*
 	 * If the selected state's target residency is below the tick length