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thermal/intel_powerclamp: Convert to CPU hotplug state 

This is a conversation to the new hotplug state machine with
the difference that CPU_DEAD becomes CPU_PREDOWN.

At the same time it makes the handling of the two states symmetrical.
stop_power_clamp_worker() is called unconditionally and the controversial
error message is removed.

Finally, the hotplug state callbacks are removed after the powerclamping
is stopped to avoid a potential race.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
[pmladek@suse.com: Fixed the possible race in powerclamp_exit()]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Sebastian Andrzej Siewior 2016-11-28 13:44:51 -08:00 committed by Rafael J. Wysocki
parent 8d962ac7f3
commit cb91fef1b7
1 changed files with 37 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

75
drivers/thermal/intel_powerclamp.c
View File

@ -43,7 +43,6 @@
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/cpu.h>
#include <linux/thermal.h>
#include <linux/slab.h>
@ -530,8 +529,7 @@ static void start_power_clamp_worker(unsigned long cpu)
struct powerclamp_worker_data *w_data = per_cpu_ptr(worker_data, cpu);
struct kthread_worker *worker;
worker = kthread_create_worker_on_cpu(cpu, KTW_FREEZABLE,
"kidle_inject/%ld", cpu);
worker = kthread_create_worker_on_cpu(cpu, 0, "kidle_inject/%ld", cpu);
if (IS_ERR(worker))
return;
@ -622,42 +620,34 @@ static void end_power_clamp(void)
}
}
static int powerclamp_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
static int powerclamp_cpu_online(unsigned int cpu)
{
unsigned long cpu = (unsigned long)hcpu;
if (false == clamping)
goto exit_ok;
switch (action) {
case CPU_ONLINE:
start_power_clamp_worker(cpu);
/* prefer BSP as controlling CPU */
if (cpu == 0) {
control_cpu = 0;
smp_mb();
}
break;
case CPU_DEAD:
if (test_bit(cpu, cpu_clamping_mask)) {
pr_err("cpu %lu dead but powerclamping thread is not\n",
cpu);
stop_power_clamp_worker(cpu);
}
if (cpu == control_cpu) {
control_cpu = smp_processor_id();
smp_mb();
}
if (clamping == false)
return 0;
start_power_clamp_worker(cpu);
/* prefer BSP as controlling CPU */
if (cpu == 0) {
control_cpu = 0;
smp_mb();
}
exit_ok:
return NOTIFY_OK;
return 0;
}
static struct notifier_block powerclamp_cpu_notifier = {
.notifier_call = powerclamp_cpu_callback,
};
static int powerclamp_cpu_predown(unsigned int cpu)
{
if (clamping == false)
return 0;
stop_power_clamp_worker(cpu);
if (cpu != control_cpu)
return 0;
control_cpu = cpumask_first(cpu_online_mask);
if (control_cpu == cpu)
control_cpu = cpumask_next(cpu, cpu_online_mask);
smp_mb();
return 0;
}
static int powerclamp_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
@ -788,6 +778,8 @@ file_error:
debugfs_remove_recursive(debug_dir);
}
static enum cpuhp_state hp_state;
static int __init powerclamp_init(void)
{
int retval;
@ -805,7 +797,14 @@ static int __init powerclamp_init(void)
/* set default limit, maybe adjusted during runtime based on feedback */
window_size = 2;
register_hotcpu_notifier(&powerclamp_cpu_notifier);
retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
"thermal/intel_powerclamp:online",
powerclamp_cpu_online,
powerclamp_cpu_predown);
if (retval < 0)
goto exit_free;
hp_state = retval;
worker_data = alloc_percpu(struct powerclamp_worker_data);
if (!worker_data) {
@ -830,7 +829,7 @@ static int __init powerclamp_init(void)
exit_free_thread:
free_percpu(worker_data);
exit_unregister:
unregister_hotcpu_notifier(&powerclamp_cpu_notifier);
cpuhp_remove_state_nocalls(hp_state);
exit_free:
kfree(cpu_clamping_mask);
return retval;
@ -839,8 +838,8 @@ module_init(powerclamp_init);
static void __exit powerclamp_exit(void)
{
unregister_hotcpu_notifier(&powerclamp_cpu_notifier);
end_power_clamp();
cpuhp_remove_state_nocalls(hp_state);
free_percpu(worker_data);
thermal_cooling_device_unregister(cooling_dev);
kfree(cpu_clamping_mask);