[patch 39/66] clocksource/dummy_timer: Convert to hotplug state machine
From: Anna-Maria Gleixner <anna-maria@linutronix.de>
Date: 2016-07-11 12:40:51
Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. Signed-off-by: Richard Cochran <redacted> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Lezcano <redacted> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> --- drivers/clocksource/dummy_timer.c | 36 ++++++------------------------------ include/linux/cpuhotplug.h | 1 + 2 files changed, 7 insertions(+), 30 deletions(-)
--- a/drivers/clocksource/dummy_timer.c
+++ b/drivers/clocksource/dummy_timer.c@@ -16,10 +16,9 @@ static DEFINE_PER_CPU(struct clock_event_device, dummy_timer_evt); -static void dummy_timer_setup(void) +static int dummy_timer_starting_cpu(unsigned int cpu) { - int cpu = smp_processor_id(); - struct clock_event_device *evt = raw_cpu_ptr(&dummy_timer_evt); + struct clock_event_device *evt = per_cpu_ptr(&dummy_timer_evt, cpu); evt->name = "dummy_timer"; evt->features = CLOCK_EVT_FEAT_PERIODIC |
@@ -29,36 +28,13 @@ static void dummy_timer_setup(void) evt->cpumask = cpumask_of(cpu); clockevents_register_device(evt); + return 0; } -static int dummy_timer_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) -{ - if ((action & ~CPU_TASKS_FROZEN) == CPU_STARTING) - dummy_timer_setup(); - - return NOTIFY_OK; -} - -static struct notifier_block dummy_timer_cpu_nb = { - .notifier_call = dummy_timer_cpu_notify, -}; - static int __init dummy_timer_register(void) { - int err = 0; - - cpu_notifier_register_begin(); - err = __register_cpu_notifier(&dummy_timer_cpu_nb); - if (err) - goto out; - - /* We won't get a call on the boot CPU, so register immediately */ - if (num_possible_cpus() > 1) - dummy_timer_setup(); - -out: - cpu_notifier_register_done(); - return err; + return cpuhp_setup_state(CPUHP_AP_DUMMY_TIMER_STARTING, + "AP_DUMMY_TIMER_STARTING", + dummy_timer_starting_cpu, NULL); } early_initcall(dummy_timer_register); --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h
@@ -39,6 +39,7 @@ enum cpuhp_state { CPUHP_AP_PERF_ARM_STARTING, CPUHP_AP_ARM_ARCH_TIMER_STARTING, CPUHP_AP_ARM_GLOBAL_TIMER_STARTING, + CPUHP_AP_DUMMY_TIMER_STARTING, CPUHP_AP_KVM_STARTING, CPUHP_AP_NOTIFY_STARTING, CPUHP_AP_ONLINE,