Messages in this thread Patch in this message |  | | From | Petr Mladek <> | Subject | [PATCH 3/3] thermal/intel_powerclamp: Convert to CPU hotplug state | Date | Mon, 17 Oct 2016 14:32:52 +0200 |
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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> --- drivers/thermal/intel_powerclamp.c | 69 +++++++++++++++++++------------------- 1 file changed, 35 insertions(+), 34 deletions(-)
diff --git a/drivers/thermal/intel_powerclamp.c b/drivers/thermal/intel_powerclamp.c index a94f7c849a4e..390e50b97324 100644 --- a/drivers/thermal/intel_powerclamp.c +++ b/drivers/thermal/intel_powerclamp.c @@ -622,43 +622,35 @@ 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 (clamping == false) + return 0; + start_power_clamp_worker(cpu); + /* prefer BSP as controlling CPU */ + if (cpu == 0) { + control_cpu = 0; + smp_mb(); + } + return 0; +} - if (false == clamping) - goto exit_ok; +static int powerclamp_cpu_predown(unsigned int cpu) +{ + if (clamping == false) + return 0; - 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(); - } - } + stop_power_clamp_worker(cpu); + if (cpu != control_cpu) + return 0; -exit_ok: - return NOTIFY_OK; + control_cpu = cpumask_first(cpu_online_mask); + if (control_cpu == cpu) + control_cpu = cpumask_next(cpu, cpu_online_mask); + smp_mb(); + return 0; } -static struct notifier_block powerclamp_cpu_notifier = { - .notifier_call = powerclamp_cpu_callback, -}; - static int powerclamp_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) { @@ -788,6 +780,8 @@ static inline void powerclamp_create_debug_files(void) debugfs_remove_recursive(debug_dir); } +static enum cpuhp_state hp_state; + static int __init powerclamp_init(void) { int retval; @@ -805,7 +799,14 @@ 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 +831,7 @@ 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 +840,8 @@ static int __init powerclamp_init(void) 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); -- 1.8.5.6
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