You can see linux/Documentation/memory_barriers.txt about barriers in common

i think, that specific definition of __memory_barrier depend on architecture. What file did you found this definition in?

2011/3/6 loody <miloody@gmail.com>

hi all:
I grep kernel source and found cpu_relax is defined as
__memory_barrier(), which seems not defined in kernel source.
At beginning I think it may be the gcc build-in functions, but I
cannot find in the gcc document.
Where and what is that used for?

--
Regards,
miloody

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