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Date: Fri, 9 Sep 2016 15:39:24 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Nicolas Pitre <nico@fluxnic.net>
cc: John Stultz <john.stultz@linaro.org>, linux-kernel@vger.kernel.org
Subject: Re: [RFC/PATCH] posix-timers: make them configurable
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On Thu, 8 Sep 2016, Nicolas Pitre wrote:
> Small embedded systems typically don't need them.  This removes about
> 16KB from the kernel binary size on ARM when configured out.  
> Corresponding syscalls are routed to a stub logging the attempt to
> use those syscalls which should be enough of a clue if they were 
> disabled without proper consideration.
> 
> Signed-off-by: Nicolas Pitre <nico@linaro.org>
> 
> diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig
> index ee3de3421f..00e6098e9a 100644
> --- a/drivers/ptp/Kconfig
> +++ b/drivers/ptp/Kconfig
> @@ -6,7 +6,7 @@ menu "PTP clock support"
>  
>  config PTP_1588_CLOCK
>  	tristate "PTP clock support"
> -	depends on NET
> +	depends on NET && POSIX_TIMERS
>  	select PPS
>  	select NET_PTP_CLASSIFY
>  	help

You forgot CONFIG_TIMERFD ....

> +void do_schedule_next_timer(struct siginfo *info)
> +{
> +}

 ....

> +void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
> +{
> +}

You should make them static inlines in the headers so they get compiled out
completely.

Thanks,

	tglx