[PATCH 08/36] cpuidle,psci: Push RCU-idle into driver

From: Peter Zijlstra
Date: Wed Jun 08 2022 - 10:47:39 EST


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

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
drivers/cpuidle/cpuidle-psci.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

--- a/drivers/cpuidle/cpuidle-psci.c
+++ b/drivers/cpuidle/cpuidle-psci.c
@@ -69,12 +69,12 @@ static int __psci_enter_domain_idle_stat
return -1;

/* Do runtime PM to manage a hierarchical CPU toplogy. */
- rcu_irq_enter_irqson();
if (s2idle)
dev_pm_genpd_suspend(pd_dev);
else
pm_runtime_put_sync_suspend(pd_dev);
- rcu_irq_exit_irqson();
+
+ rcu_idle_enter();

state = psci_get_domain_state();
if (!state)
@@ -82,12 +82,12 @@ static int __psci_enter_domain_idle_stat

ret = psci_cpu_suspend_enter(state) ? -1 : idx;

- rcu_irq_enter_irqson();
+ rcu_idle_exit();
+
if (s2idle)
dev_pm_genpd_resume(pd_dev);
else
pm_runtime_get_sync(pd_dev);
- rcu_irq_exit_irqson();

cpu_pm_exit();

@@ -240,6 +240,7 @@ static int psci_dt_cpu_init_topology(str
* 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 = psci_enter_domain_idle_state;
drv->states[state_count - 1].enter_s2idle = psci_enter_s2idle_domain_idle_state;
psci_cpuidle_use_cpuhp = true;