[patch 2/2] powerpc: optimise smp_wmb

Segher Boessenkool segher at kernel.crashing.org
Thu May 22 06:16:31 EST 2008


> +#ifdef __SUBARCH_HAS_LWSYNC
> +#    define SMPWMB      lwsync
> +#else
> +#    define SMPWMB      eieio
> +#endif
> +
>  #define smp_mb()	mb()
>  #define smp_rmb()	rmb()
> -#define smp_wmb()	eieio()
> +#define smp_wmb()	__asm__ __volatile__ (__stringify(SMPWMB) : : 
> :"memory")

SMPWMB is used only here.  Why not just

#ifdef __SUBARCH_HAS_LWSYNC
#define smp_wmb() lwsync()
#else
#define smp_wmb() eieio()
#endif

?


Segher




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