linux-kernel - [PATCH 07/10] cpuidle, armada: Push RCU-idle into driver

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Date:   Fri, 3 Mar 2023 17:23:29 +0800
From:   Cheng-Jui Wang <cheng-jui.wang@...iatek.com>
To:     <stable@...r.kernel.org>, "Rafael J. Wysocki" <rafael@...nel.org>,
        "Daniel Lezcano" <daniel.lezcano@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>
CC:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Cheng-Jui Wang <cheng-jui.wang@...iatek.com>,
        <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>
Subject: [PATCH 07/10] cpuidle, armada: Push RCU-idle into driver

From: Peter Zijlstra <peterz@...radead.org>

commit 4ce40e9dbe83153f60d7e4ccd24a1eb4f8264f6a upstream.

Doing RCU-idle outside the driver, only to then temporarily enable it
again before going idle is suboptimal.

Notably the cpu_pm_*() calls implicitly re-enable RCU for a bit.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Tested-by: Tony Lindgren <tony@...mide.com>
Tested-by: Ulf Hansson <ulf.hansson@...aro.org>
Reviewed-by: Frederic Weisbecker <frederic@...nel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Link: https://lore.kernel.org/r/20230112195539.946630819@infradead.org
Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
Signed-off-by: Cheng-Jui Wang <cheng-jui.wang@...iatek.com>
---
 drivers/cpuidle/cpuidle-mvebu-v7.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/cpuidle/cpuidle-mvebu-v7.c b/drivers/cpuidle/cpuidle-mvebu-v7.c
index 01a856971f05..c9568aa9410c 100644
--- a/drivers/cpuidle/cpuidle-mvebu-v7.c
+++ b/drivers/cpuidle/cpuidle-mvebu-v7.c
@@ -36,7 +36,10 @@ static int mvebu_v7_enter_idle(struct cpuidle_device *dev,
 	if (drv->states[index].flags & MVEBU_V7_FLAG_DEEP_IDLE)
 		deepidle = true;
 
+	ct_idle_enter();
 	ret = mvebu_v7_cpu_suspend(deepidle);
+	ct_idle_exit();
+
 	cpu_pm_exit();
 
 	if (ret)
@@ -49,6 +52,7 @@ static struct cpuidle_driver armadaxp_idle_driver = {
 	.name			= "armada_xp_idle",
 	.states[0]		= ARM_CPUIDLE_WFI_STATE,
 	.states[1]		= {
+		.flags			= CPUIDLE_FLAG_RCU_IDLE,
 		.enter			= mvebu_v7_enter_idle,
 		.exit_latency		= 100,
 		.power_usage		= 50,
@@ -57,6 +61,7 @@ static struct cpuidle_driver armadaxp_idle_driver = {
 		.desc			= "CPU power down",
 	},
 	.states[2]		= {
+		.flags			= CPUIDLE_FLAG_RCU_IDLE,
 		.enter			= mvebu_v7_enter_idle,
 		.exit_latency		= 1000,
 		.power_usage		= 5,
@@ -72,6 +77,7 @@ static struct cpuidle_driver armada370_idle_driver = {
 	.name			= "armada_370_idle",
 	.states[0]		= ARM_CPUIDLE_WFI_STATE,
 	.states[1]		= {
+		.flags			= CPUIDLE_FLAG_RCU_IDLE,
 		.enter			= mvebu_v7_enter_idle,
 		.exit_latency		= 100,
 		.power_usage		= 5,
@@ -87,6 +93,7 @@ static struct cpuidle_driver armada38x_idle_driver = {
 	.name			= "armada_38x_idle",
 	.states[0]		= ARM_CPUIDLE_WFI_STATE,
 	.states[1]		= {
+		.flags			= CPUIDLE_FLAG_RCU_IDLE,
 		.enter			= mvebu_v7_enter_idle,
 		.exit_latency		= 10,
 		.power_usage		= 5,
-- 
2.18.0