Re: can somebody explain barrier() macro ?

[Erik Mouw]

On Tue, Feb 20, 2001 at 12:50:54PM -0700, [e-mail] wrote:
> barrier() is defined in kernel.h as follows :
> 
> #define barrier() __asm__ __volatile__("": : :"memory")
> 
> what does this mean ? is this like "nop" ?

It's a write barrier. It prevents the compiler from optimising writes
to memory: all outstanding writes should be done before the program
flow crosses the barrier().

Erik

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J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
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