Commit 5fca0d9f authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

cpuidle, tegra: Push RCU-idle into driver 



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

Notably once implicitly through the cpu_pm_*() calls and once
explicitly doing RCU_NONIDLE().

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Tested-by: default avatarTony Lindgren <tony@atomide.com>
Tested-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20230112195539.699546331@infradead.org
parent 8e9ab9e8

drivers/cpuidle/cpuidle-tegra.c

+16 −5
Original line number Diff line number Diff line
@@ -180,9 +180,11 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev, 
	}



	local_fiq_disable();

	RCU_NONIDLE(tegra_pm_set_cpu_in_lp2());

	tegra_pm_set_cpu_in_lp2();

	cpu_pm_enter();



	ct_idle_enter();



	switch (index) {

	case TEGRA_C7:

		err = tegra_cpuidle_c7_enter();
@@ -197,8 +199,10 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev, 
		break;

	}



	ct_idle_exit();



	cpu_pm_exit();

	RCU_NONIDLE(tegra_pm_clear_cpu_in_lp2());

	tegra_pm_clear_cpu_in_lp2();

	local_fiq_enable();



	return err ?: index;
@@ -226,6 +230,7 @@ static int tegra_cpuidle_enter(struct cpuidle_device *dev, 
			       struct cpuidle_driver *drv,

			       int index)

{

	bool do_rcu = drv->states[index].flags & CPUIDLE_FLAG_RCU_IDLE;

	unsigned int cpu = cpu_logical_map(dev->cpu);

	int ret;
@@ -233,9 +238,13 @@ static int tegra_cpuidle_enter(struct cpuidle_device *dev, 
	if (dev->states_usage[index].disable)

		return -1;



	if (index == TEGRA_C1)

	if (index == TEGRA_C1) {

		if (do_rcu)

			ct_idle_enter();

		ret = arm_cpuidle_simple_enter(dev, drv, index);

	else

		if (do_rcu)

			ct_idle_exit();

	} else

		ret = tegra_cpuidle_state_enter(dev, index, cpu);



	if (ret < 0) {
@@ -285,7 +294,8 @@ static struct cpuidle_driver tegra_idle_driver = { 
			.exit_latency		= 2000,

			.target_residency	= 2200,

			.power_usage		= 100,

			.flags			= CPUIDLE_FLAG_TIMER_STOP,

			.flags			= CPUIDLE_FLAG_TIMER_STOP |

						  CPUIDLE_FLAG_RCU_IDLE,

			.name			= "C7",

			.desc			= "CPU core powered off",

		},
@@ -295,6 +305,7 @@ static struct cpuidle_driver tegra_idle_driver = { 
			.target_residency	= 10000,

			.power_usage		= 0,

			.flags			= CPUIDLE_FLAG_TIMER_STOP |

						  CPUIDLE_FLAG_RCU_IDLE   |

						  CPUIDLE_FLAG_COUPLED,

			.name			= "CC6",

			.desc			= "CPU cluster powered off",