* Peter Zijlstra <pet...@infradead.org> wrote:
> On Thu, Jun 04, 2015 at 07:59:30AM +0200, Ingo Molnar wrote:
>
> > > --- a/include/linux/hrtimer.h
> > > +++ b/include/linux/hrtimer.h
> > > @@ -123,8 +123,10 @@ struct hrtimer_sleeper {
> > >
> > > #ifdef CONFIG_64BIT
> > > # define HRTIMER_CLOCK_BASE_ALIGN 64
> > > +# define __timer_base_running(timer) timer->base->running
> > > #else
> > > # define HRTIMER_CLOCK_BASE_ALIGN 32
> > > +# define __timer_base_running(timer) timer->base->cpu_base->running
> > > #endif
> >
> > Please put it into the cpu_base on 64-bit as well: the base pointer is
> > available
> > already on 64-bit so there should be no measurable performance difference,
> > and
> > readability is a primary concern with all this code.
>
> That's an extra pointer chase for no reason :-(
Only if we otherwise don't dereference cpu_base - is that the case in the
relevant
code paths?
If we already dereference cpu_base (say for the lock) and have its value loaded
then it's totally equivalent to chasing down it in base->.
Thanks,
Ingo
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