Re: [RFC][patch 4/5] clocksource_read/clocksource_read_raw inlinefunctions

From: john stultz
Date: Tue Jul 21 2009 - 18:01:24 EST


On Tue, 2009-07-21 at 21:17 +0200, Martin Schwidefsky wrote:
> plain text document attachment (clocksource-read-ns.diff)
> From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
>
> Add clocksource_read / clocksource_read_raw inline functions and use
> them for getnstimeofday, ktime_get, ktime_get_ts and getrawmonotonic.
>
> Cc: Ingo Molnar <mingo@xxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: john stultz <johnstul@xxxxxxxxxx>
> Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
> ---
> include/linux/clocksource.h | 45 +++++++++++++++++++++++++++++++++++++++++++
> kernel/time/timekeeping.c | 46 +++-----------------------------------------
> 2 files changed, 49 insertions(+), 42 deletions(-)
>
> Index: linux-2.6/include/linux/clocksource.h
> ===================================================================
> --- linux-2.6.orig/include/linux/clocksource.h
> +++ linux-2.6/include/linux/clocksource.h
> @@ -284,6 +284,51 @@ static inline s64 cyc2ns(struct clocksou
> return ret;
> }
>
> +/**
> + * clocksource_read: - Read nanosecond delta from clocksource.
> + * @cs: pointer to clocksource being read
> + *
> + * Read from the clock source and return the clock value converted
> + * to nanoseconds.
> + */
> +static inline s64 clocksource_read(struct clocksource *cs)
> +{
> + cycle_t cycle_now, cycle_delta;
> +
> + /* read clocksource: */
> + cycle_now = cs->read(cs);
> +
> + /* calculate the delta since the last update_wall_time: */
> + cycle_delta = (cycle_now - cs->cycle_last) & cs->mask;
> +
> + /* convert to nanoseconds: */
> + return cyc2ns(cs, cycle_delta);
> +}

Oof. So you took out clocksource_read() only to replace with a different
function with the same name? If this move is necessary, could we call
these clocksource_get_ns()/clocksource_get_raw_ns() to avoid the
confusion?

thanks
-john


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