Re: [PATCH] timekeeping: drop irq-context clocksource polling

Daniel Walker
2007-04-05T21:30:53Z

On Thu, 2007-04-05 at 14:25 -0700, john stultz wrote:
> On Thu, 2007-04-05 at 14:03 -0700, Daniel Walker wrote:
> > Before this change the timekeeping code would poll the clocksource
> > list every interrupt. This changes that so the clocksource list is
> > only checked when there has been and update, and no longer checks
> > in interrupt context.
> >
> > This also has a few small space and line cleanups.
> >
> > Boot tested on i386, compile tested on x86_64 .. However, I couldn't
> > find a !GENERIC_TIME that compiled without this change so it's untested..
> >
> > Signed-Off-By: Daniel Walker <dwalker@mvista.com>
>
> Err.. I think you need to be holding a write on the xtime_lock (as is
> done before calling update_wall_time()) when changing the clocksource.

I added a write_seqlock_irqsave() on xtime_lock in
change_clocksource() .. Did I need more (different) protection than
that?

Daniel