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

[Mathieu Desnoyers <compudj@krystal.dyndns.org>]

* Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca) 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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