Re: [PATCH 11/13] timekeeping: remove xtime_update

Arnd Bergmann
2020-10-12T13:37:09Z

On Mon, Oct 12, 2020 at 3:16 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Thu, Oct 8, 2020 at 5:48 PM Arnd Bergmann <arnd@arndb.de> wrote:
> > There are no more users of xtime_update aside from legacy_timer_tick(),
> > so fold it into that function and remove the declaration.
> >
> > update_process_times() is now only called inside of the kernel/time/
> > code, so the declaration can be moved there.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>
> Thanks for your patch!
>
> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
>
> The comment about xtime_update() in arch/ia64/kernel/time.c needs
> an update.

I think the correct action for ia64 would be to make it a
proper clockevent driver with oneshot support, and remove
the rest of this logic.

I could try to rewrite the comment, but I tried not to touch that
part since I don't understand the logic behind it. Maybe the
ia64 maintainers can comment here why it even tries to skip
a timer tick. Is there a danger of ending up with the timer irq
permanently disabled if the timer_interrupt() function returns
with the itm register in the past, or is this simply about not having
too many interrupts in a row?

> Does the comment about update_process_times() in
> arch/openrisc/kernel/time.c needs an update, too?

I think that one is still technically correct.

Arnd