[tip:smp/hotplug] cpuidle/coupled: Convert to hotplug state machine

From: tip-bot for Sebastian Andrzej Siewior
Date: Tue Sep 06 2016 - 12:42:58 EST


Commit-ID: dfc616d8b3df3013c579e023e67f29ada60bdd50
Gitweb: http://git.kernel.org/tip/dfc616d8b3df3013c579e023e67f29ada60bdd50
Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate: Wed, 24 Aug 2016 11:14:44 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 6 Sep 2016 18:30:24 +0200

cpuidle/coupled: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: linux-pm@xxxxxxxxxxxxxxx
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: rt@xxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20160824091444.brdr5zpbxjvh6n3f@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
drivers/cpuidle/coupled.c | 75 +++++++++++++++++++---------------------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 32 insertions(+), 44 deletions(-)

diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
index d5657d5..71e586d 100644
--- a/drivers/cpuidle/coupled.c
+++ b/drivers/cpuidle/coupled.c
@@ -749,65 +749,52 @@ static void cpuidle_coupled_allow_idle(struct cpuidle_coupled *coupled)
put_cpu();
}

-/**
- * cpuidle_coupled_cpu_notify - notifier called during hotplug transitions
- * @nb: notifier block
- * @action: hotplug transition
- * @hcpu: target cpu number
- *
- * Called when a cpu is brought on or offline using hotplug. Updates the
- * coupled cpu set appropriately
- */
-static int cpuidle_coupled_cpu_notify(struct notifier_block *nb,
- unsigned long action, void *hcpu)
+static int coupled_cpu_online(unsigned int cpu)
{
- int cpu = (unsigned long)hcpu;
struct cpuidle_device *dev;

- switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_UP_PREPARE:
- case CPU_DOWN_PREPARE:
- case CPU_ONLINE:
- case CPU_DEAD:
- case CPU_UP_CANCELED:
- case CPU_DOWN_FAILED:
- break;
- default:
- return NOTIFY_OK;
- }
-
mutex_lock(&cpuidle_lock);

dev = per_cpu(cpuidle_devices, cpu);
- if (!dev || !dev->coupled)
- goto out;
-
- switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_UP_PREPARE:
- case CPU_DOWN_PREPARE:
- cpuidle_coupled_prevent_idle(dev->coupled);
- break;
- case CPU_ONLINE:
- case CPU_DEAD:
+ if (dev && dev->coupled) {
cpuidle_coupled_update_online_cpus(dev->coupled);
- /* Fall through */
- case CPU_UP_CANCELED:
- case CPU_DOWN_FAILED:
cpuidle_coupled_allow_idle(dev->coupled);
- break;
}

-out:
mutex_unlock(&cpuidle_lock);
- return NOTIFY_OK;
+ return 0;
}

-static struct notifier_block cpuidle_coupled_cpu_notifier = {
- .notifier_call = cpuidle_coupled_cpu_notify,
-};
+static int coupled_cpu_up_prepare(unsigned int cpu)
+{
+ struct cpuidle_device *dev;
+
+ mutex_lock(&cpuidle_lock);
+
+ dev = per_cpu(cpuidle_devices, cpu);
+ if (dev && dev->coupled)
+ cpuidle_coupled_prevent_idle(dev->coupled);
+
+ mutex_unlock(&cpuidle_lock);
+ return 0;
+}

static int __init cpuidle_coupled_init(void)
{
- return register_cpu_notifier(&cpuidle_coupled_cpu_notifier);
+ int ret;
+
+ ret = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_COUPLED_PREPARE,
+ "cpuidle/coupled:prepare",
+ coupled_cpu_up_prepare,
+ coupled_cpu_online);
+ if (ret)
+ return ret;
+ ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+ "cpuidle/coupled:online",
+ coupled_cpu_online,
+ coupled_cpu_up_prepare);
+ if (ret < 0)
+ cpuhp_remove_state_nocalls(CPUHP_CPUIDLE_COUPLED_PREPARE);
+ return ret;
}
core_initcall(cpuidle_coupled_init);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 0fb22b9..e860877 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -30,6 +30,7 @@ enum cpuhp_state {
CPUHP_SLAB_PREPARE,
CPUHP_MD_RAID5_PREPARE,
CPUHP_RCUTREE_PREP,
+ CPUHP_CPUIDLE_COUPLED_PREPARE,
CPUHP_NOTIFY_PREPARE,
CPUHP_TIMERS_DEAD,
CPUHP_BRINGUP_CPU,