Re: [PATCH 05/10] local_t : mips extension

From: Mathieu Desnoyers
Date: Fri Jan 26 2007 - 11:58:28 EST


* Mathieu Desnoyers (mathieu.desnoyers@xxxxxxxxxx) wrote:
> > What I generally dislike about this patch is that several fairly large
> > functions have been duplicated with only little change.
> >
>
> Yeah, I know. Until we find some way to share atomic operation code for
> both operation on local and shared data, we have to duplicate this. We
> could think about a header that would support multiple inclusion and
> behave differently (different function prefix and LOCKing/memory
> barriers) depending on defines set by the top level header.
>
> Something like
>
> asm/atomic.h
> #define ATOMIC_SHARED
> #include <asm/atomic-ops.h> /* shared */
> #undef ATOMIC_SHARED
> #include <asm/atomic-ops.h> /* local */
>
> asm/atomic-ops.h
> #ifdef ATOMIC_SHARED
> #define ATOMIC_PREFIX atomic
> #define ATOMIC_BARRIER() smp_mb()
> #define ATOMIC_TYPE atomic_t
> #define ATOMIC_VAR (v->counter)
> #else
> #define ATOMIC_PREFIX local
> #define ATOMIC_BARRIER()
> #define ATOMIC_TYPE local_t
> #define ATOMIC_VAR (v->a.counter)
> #endif
>
> static __inline__ ATOMIC_PREFIX##_add_return(int i, ATOMIC_TYPE *v)
> .....
> #undef ATOMIC_PREFIX
> #undef ATOMIC_BARRIER
> #undef ATOMIC_TYPE
> #undef ATOMIC_VAR
>

More prefisely, for this to work, we should change :
#define ATOMIC_PREFIX atomic
and
#define ATOMIC_PREFIX local
for

#define ATOMICF(fctname) atomic_##fctname
and
#define ATOMICF(fctname) local_##fctname


which would make de declaration look like :

static __inline__ ATOMICF(add_return)(int i, ATOMIC_TYPE *v)

Which starts to look a little odd to me, doesn't it ?

Regards,

Mathieu

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