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[v2,6/7] ARM64: smp: Add runtime PM support for CPU hotplug

Message ID 1441310314-8857-7-git-send-email-lina.iyer@linaro.org
State New
Headers show

Commit Message

Lina Iyer Sept. 3, 2015, 7:58 p.m. UTC
Enable runtime PM for CPU devices. Do a runtime get of the CPU device
when the CPU is hotplugged in and runtime put of the CPU device when the
CPU is hotplugged off. When all the CPUs in a domain are hotplugged off,
the domain may also be powered off and cluster_pm_enter/exit()
notifications are be sent out.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 arch/arm64/kernel/smp.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

Comments

Geert Uytterhoeven Sept. 30, 2015, 12:36 p.m. UTC | #1
Hi Lina,

On Thu, Sep 3, 2015 at 9:58 PM, Lina Iyer <lina.iyer@linaro.org> wrote:
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index dbdaacd..4076962 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -135,6 +135,7 @@ asmlinkage void secondary_start_kernel(void)
>  {
>         struct mm_struct *mm = &init_mm;
>         unsigned int cpu = smp_processor_id();
> +       struct device *cpu_dev;
>
>         /*
>          * All kernel threads share the same mm context; grab a
> @@ -185,6 +186,11 @@ asmlinkage void secondary_start_kernel(void)
>         local_irq_enable();
>         local_async_enable();
>
> +       /* We are running, enable runtime PM for the CPU. */
> +       cpu_dev = get_cpu_device(cpu);
> +       if (cpu_dev)
> +               pm_runtime_get_sync(cpu_dev);

arch/arm64/kernel/smp.c:192:3: error: implicit declaration of function
'pm_runtime_get_sync' [-Werror=implicit-function-declaration]

Adding #include <linux/pm_runtime.h> fixes compilation.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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diff mbox

Patch

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index dbdaacd..4076962 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -135,6 +135,7 @@  asmlinkage void secondary_start_kernel(void)
 {
 	struct mm_struct *mm = &init_mm;
 	unsigned int cpu = smp_processor_id();
+	struct device *cpu_dev;
 
 	/*
 	 * All kernel threads share the same mm context; grab a
@@ -185,6 +186,11 @@  asmlinkage void secondary_start_kernel(void)
 	local_irq_enable();
 	local_async_enable();
 
+	/* We are running, enable runtime PM for the CPU. */
+	cpu_dev = get_cpu_device(cpu);
+	if (cpu_dev)
+		pm_runtime_get_sync(cpu_dev);
+
 	/*
 	 * OK, it's off to the idle thread for us
 	 */
@@ -292,6 +298,16 @@  void __cpu_die(unsigned int cpu)
 void cpu_die(void)
 {
 	unsigned int cpu = smp_processor_id();
+	struct device *cpu_dev;
+
+	/*
+	 * We dont need the CPU device anymore.
+	 * Lets do this before IRQs are disabled to allow
+	 * runtime PM to suspend the domain as well.
+	 */
+	cpu_dev = get_cpu_device(cpu);
+	if (cpu_dev)
+		pm_runtime_put_sync(cpu_dev);
 
 	idle_task_exit();