From: Peter Zijlstra peterz@infradead.org
commit 5fca0d9f5d76664786ca6c09076341def165a677 upstream.
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: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Ingo Molnar mingo@kernel.org Tested-by: Tony Lindgren tony@atomide.com Tested-by: Ulf Hansson ulf.hansson@linaro.org Reviewed-by: Frederic Weisbecker frederic@kernel.org Acked-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Link: https://lore.kernel.org/r/20230112195539.699546331@infradead.org Signed-off-by: Suren Baghdasaryan surenb@google.com Signed-off-by: Cheng-Jui Wang cheng-jui.wang@mediatek.com --- drivers/cpuidle/cpuidle-tegra.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/drivers/cpuidle/cpuidle-tegra.c b/drivers/cpuidle/cpuidle-tegra.c index 9845629aeb6d..3ca5cfb9d322 100644 --- a/drivers/cpuidle/cpuidle-tegra.c +++ b/drivers/cpuidle/cpuidle-tegra.c @@ -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",