linux-kernel - Re: [PATCH v2] tick/broadcast: Allow later registered device enter oneshot mode

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Date:   Wed, 31 Mar 2021 10:06:57 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Jindong Yue <jindong.yue@....com>, fweisbec@...il.com,
        mingo@...nel.org
Cc:     linux-kernel@...r.kernel.org, jindong.yue@....com
Subject: Re: [PATCH v2] tick/broadcast: Allow later registered device enter oneshot mode

On Wed, Mar 31 2021 at 09:10, Jindong Yue wrote:
> --- a/kernel/time/tick-broadcast.c
> +++ b/kernel/time/tick-broadcast.c
> @@ -47,6 +47,7 @@ static inline void tick_resume_broadcast_oneshot(struct clock_event_device *bc)
>  static inline void tick_broadcast_oneshot_offline(unsigned int cpu) { }
>  # endif
>  #endif
> +static void tick_handle_oneshot_broadcast(struct clock_event_device *dev);

Leftover ...
  
>  /*
>   * Debugging: see timer_list.c
> @@ -107,6 +108,19 @@ void tick_install_broadcast_device(struct clock_event_device *dev)
>  	tick_broadcast_device.evtdev = dev;
>  	if (!cpumask_empty(tick_broadcast_mask))
>  		tick_broadcast_start_periodic(dev);
> +
> +	if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
> +		return;
> +
> +	/*
> +	 * If system already runs in oneshot mode, switch new registered

the system .... the newly registered

> +	 * broadcast device to oneshot mode explicitly if possiable.

s/possible/possiable/

But the 'if possible' makes no sense here. The above check for
CLOCK_EVT_FEAT_ONESHOT established that it _is_ possible. So just remove
the 'if ...'.

> +	 */
> +	if (tick_broadcast_oneshot_active()) {
> +		tick_broadcast_switch_to_oneshot();
> +		return;
> +	}

Thanks,

        tglx