linux-kernel - Re: [PATCH v2 14/25] timekeeping: Introduce combined timekeeping action flag

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Message-ID: <CANDhNCpDySwAsx20Wwm3_Np=e2venKx16a0BYVmq9j_XmpEjUg@mail.gmail.com>
Date: Thu, 24 Oct 2024 15:12:53 -0700
From: John Stultz <jstultz@...gle.com>
To: Anna-Maria Behnsen <anna-maria@...utronix.de>
Cc: Frederic Weisbecker <frederic@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, 
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org, 
	Miroslav Lichvar <mlichvar@...hat.com>, Richard Cochran <richardcochran@...il.com>, 
	Christopher S Hall <christopher.s.hall@...el.com>
Subject: Re: [PATCH v2 14/25] timekeeping: Introduce combined timekeeping
 action flag

On Wed, Oct 9, 2024 at 1:29 AM Anna-Maria Behnsen
<anna-maria@...utronix.de> wrote:
>
> Instead of explicitly listing all the separate timekeeping actions flags,
> introduce a new one which covers all actions except TK_MIRROR action.
>
> No functional change.
>
> Signed-off-by: Anna-Maria Behnsen <anna-maria@...utronix.de>
> ---
>  kernel/time/timekeeping.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
> index fcb2b8b232d2..5a747afe64b4 100644
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -33,6 +33,8 @@
>  #define TK_MIRROR              (1 << 1)
>  #define TK_CLOCK_WAS_SET       (1 << 2)
>
> +#define TK_UPDATE_ALL          (TK_CLEAR_NTP | TK_CLOCK_WAS_SET)
> +

Hrm.  I feel a little wary around having a flag mask called _ALL when
it doesn't actually include all the other flags.
I also recognize the "TK_CLEAR_NTP | TK_CLOCK_WAS_SET"  arguments can
feel repetitive, but I find having them explicitly listed makes the
code more readable to me.
Combining these common ones together just means there is a 4th option
one has to keep in their head to translate.

Further, as I look through the logic TK_MIRROR could probably be
improved by adding a direction (it's easy to mix up what is being
mirrored to what). Maybe TK_MIRROR_TO_SHADOW?

But these are mostly just strategies to help my scatterbrained state,
so this isn't a hard objection if you disagree.

thanks
-john