Re: [PATCH 1/4] watchdog: introduce watchdog_park_threads() and watchdog_unpark_threads()

[Michal Hocko <mhocko@kernel.org>]

On Sat 01-08-15 14:49:22, Ulrich Obergfell wrote:
> These functions are intended to be used only from inside kernel/watchdog.c
> to park/unpark all watchdog threads that are specified in watchdog_cpumask.

I would suggest merging this into Patch2. It is usually better to add
new functions along with their users.

> Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com>
> ---
>  kernel/watchdog.c | 36 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
> index a6ffa43..5571f20 100644
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -24,6 +24,7 @@
>  #include <asm/irq_regs.h>
>  #include <linux/kvm_para.h>
>  #include <linux/perf_event.h>
> +#include <linux/kthread.h>
>  
>  /*
>   * The run state of the lockup detectors is controlled by the content of the
> @@ -666,6 +667,41 @@ static struct smp_hotplug_thread watchdog_threads = {
>  	.unpark			= watchdog_enable,
>  };
>  
> +/*
> + * park all watchdog threads that are specified in 'watchdog_cpumask'
> + */
> +static int watchdog_park_threads(void)
> +{
> +	int cpu, ret = 0;
> +
> +	get_online_cpus();
> +	for_each_watchdog_cpu(cpu) {
> +		ret = kthread_park(per_cpu(softlockup_watchdog, cpu));
> +		if (ret)
> +			break;
> +	}
> +	if (ret) {
> +		for_each_watchdog_cpu(cpu)
> +			kthread_unpark(per_cpu(softlockup_watchdog, cpu));
> +	}
> +	put_online_cpus();
> +
> +	return ret;
> +}
> +
> +/*
> + * unpark all watchdog threads that are specified in 'watchdog_cpumask'
> + */
> +static void watchdog_unpark_threads(void)
> +{
> +	int cpu;
> +
> +	get_online_cpus();
> +	for_each_watchdog_cpu(cpu)
> +		kthread_unpark(per_cpu(softlockup_watchdog, cpu));
> +	put_online_cpus();
> +}
> +
>  static void restart_watchdog_hrtimer(void *info)
>  {
>  	struct hrtimer *hrtimer = raw_cpu_ptr(&watchdog_hrtimer);
> -- 
> 1.7.11.7
> 
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-- 
Michal Hocko
SUSE Labs