linux-kernel - [PATCH 06/10] cpuidle: Remove unnecessary current_clr_polling_and

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Date:   Fri, 11 Aug 2023 19:00:45 +0200
From:   Frederic Weisbecker <frederic@...nel.org>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Frederic Weisbecker <frederic@...nel.org>,
        Marcelo Tosatti <mtosatti@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Anna-Maria Behnsen <anna-maria@...utronix.de>
Subject: [PATCH 06/10] cpuidle: Remove unnecessary current_clr_polling_and_test() from haltpoll

When cpuidle drivers ->enter() callback are called, the TIF_NR_POLLING
flag is cleared already and TIF_NEED_RESCHED checked by call_cpuidle().

Therefore calling current_clr_polling_and_test() is redundant here and
further setting of TIF_NEED_RESCHED will result in an IPI and thus an
idle loop exit. This call can be safely removed.

Cc: Marcelo Tosatti <mtosatti@...hat.com>
Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
---
 drivers/cpuidle/cpuidle-haltpoll.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
index e66df22f9695..b641bc535102 100644
--- a/drivers/cpuidle/cpuidle-haltpoll.c
+++ b/drivers/cpuidle/cpuidle-haltpoll.c
@@ -28,11 +28,8 @@ static enum cpuhp_state haltpoll_hp_state;
 static int default_enter_idle(struct cpuidle_device *dev,
 			      struct cpuidle_driver *drv, int index)
 {
-	if (current_clr_polling_and_test()) {
-		local_irq_enable();
-		return index;
-	}
 	arch_cpu_idle();
+
 	return index;
 }
 
-- 
2.34.1