Re: [PATCH v9 3/5] qrwlock, x86 - Treat all data type not biggerthan long as atomic in x86

[Waiman Long]

On 01/20/2014 10:03 AM, Peter Zijlstra wrote:
> On Tue, Jan 14, 2014 at 11:44:05PM -0500, Waiman Long wrote:
> > The generic __native_word() macro defined in include/linux/compiler.h
> > only allows "int" and "long" data types to be treated as native and
> > atomic. The x86 architecture, however, allow the use of char and short
> > data types as atomic as well.
> >
> > This patch extends the data type allowed in the __native_word() macro to
> > allow the use of char and short.
> >
> > Signed-off-by: Waiman Long<Waiman.Long@xxxxxx>
> > ---
> >   arch/x86/include/asm/barrier.h |    8 ++++++++
> >   1 files changed, 8 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
> > index 04a4890..4d3e30a 100644
> > --- a/arch/x86/include/asm/barrier.h
> > +++ b/arch/x86/include/asm/barrier.h
> > @@ -24,6 +24,14 @@
> >   #define wmb()	asm volatile("sfence" ::: "memory")
> >   #endif
> >
> > +/*
> > + * All data types<= long are atomic in x86
> > + */
> > +#ifdef __native_word
> > +#undef __native_word
> > +#endif
> > +#define __native_word(t)	(sizeof(t)<= sizeof(long))
> Yeah, not going to happen.

Does explicit list of acceptable sizes work for you?

#define __native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == 
sizeof(short) || sizeof(t) == sizeof(int ) ||
                 sizeof(t) == sizeof(long))

-Longman
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