linux-kernel - [PATCH 02/10] cpuidle, riscv: Push RCU-idle into driver

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Date:   Fri, 3 Mar 2023 17:23:24 +0800
From:   Cheng-Jui Wang <cheng-jui.wang@...iatek.com>
To:     <stable@...r.kernel.org>, Anup Patel <anup@...infault.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        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-riscv@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>
Subject: [PATCH 02/10] cpuidle, riscv: Push RCU-idle into driver

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

commit 8e9ab9e8da1eae61fdff35690d998eaf8cd527dc upstream.

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

That is, once implicitly through the cpu_pm_*() calls and once
explicitly doing ct_irq_*_irqon().

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: Anup Patel <anup@...infault.org>
Reviewed-by: Frederic Weisbecker <frederic@...nel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Link: https://lore.kernel.org/r/20230112195539.637185846@infradead.org
Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
Signed-off-by: Cheng-Jui Wang <cheng-jui.wang@...iatek.com>
---
 drivers/cpuidle/cpuidle-riscv-sbi.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c
index 05fe2902df9a..cbdbb11b972b 100644
--- a/drivers/cpuidle/cpuidle-riscv-sbi.c
+++ b/drivers/cpuidle/cpuidle-riscv-sbi.c
@@ -121,12 +121,12 @@ static int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
 		return -1;
 
 	/* Do runtime PM to manage a hierarchical CPU toplogy. */
-	ct_irq_enter_irqson();
 	if (s2idle)
 		dev_pm_genpd_suspend(pd_dev);
 	else
 		pm_runtime_put_sync_suspend(pd_dev);
-	ct_irq_exit_irqson();
+
+	ct_idle_enter();
 
 	if (sbi_is_domain_state_available())
 		state = sbi_get_domain_state();
@@ -135,12 +135,12 @@ static int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
 
 	ret = sbi_suspend(state) ? -1 : idx;
 
-	ct_irq_enter_irqson();
+	ct_idle_exit();
+
 	if (s2idle)
 		dev_pm_genpd_resume(pd_dev);
 	else
 		pm_runtime_get_sync(pd_dev);
-	ct_irq_exit_irqson();
 
 	cpu_pm_exit();
 
@@ -251,6 +251,7 @@ static int sbi_dt_cpu_init_topology(struct cpuidle_driver *drv,
 	 * of a shared state for the domain, assumes the domain states are all
 	 * deeper states.
 	 */
+	drv->states[state_count - 1].flags |= CPUIDLE_FLAG_RCU_IDLE;
 	drv->states[state_count - 1].enter = sbi_enter_domain_idle_state;
 	drv->states[state_count - 1].enter_s2idle =
 					sbi_enter_s2idle_domain_idle_state;
-- 
2.18.0