Re: [tip:perfcounters/core] x86, perfcounters: add atomic64_xchg()

From: Ingo Molnar
Date: Tue Apr 07 2009 - 09:28:50 EST



* Paul Mackerras <paulus@xxxxxxxxx> wrote:

> Ingo Molnar writes:
>
> > Complete atomic64_t support on the 32-bit side by adding atomic64_xch().
> >
> > Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> > LKML-Reference: <20090406094518.445450972@xxxxxxxxx>
> > Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> >
> >
> > ---
> > arch/x86/include/asm/atomic_32.h | 6 ++++++
> > 1 files changed, 6 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/atomic_32.h b/arch/x86/include/asm/atomic_32.h
> > index 977250e..a9fef6c 100644
> > --- a/arch/x86/include/asm/atomic_32.h
> > +++ b/arch/x86/include/asm/atomic_32.h
> > @@ -306,6 +306,12 @@ static inline void atomic64_set(atomic64_t *ptr, unsigned long long new_val)
> > } while (atomic64_cmpxchg(ptr, old_val, new_val) != old_val);
> > }
> >
> > +static inline void
> > +atomic64_xchg(atomic64_t *ptr, unsigned long long new_val)
> > +{
> > + atomic64_set(ptr, new_val);
> > +}
>
> Umm, I don't know much about x86, but that doesn't look like an
> exchange operation to me... Shouldn't it return a value, for a
> start?

Yes, indeed :) Fixed it.

/me officially loves commit notifications

Ingo
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