perf events ring buffer memory barrier on powerpc

[Peter Zijlstra]

On Wed, Oct 30, 2013 at 03:28:54PM +0200, Victor Kaplansky wrote:
> one of the authors of Documentation/memory-barriers.txt is on cc: list ;-)
> 
> Disclaimer: it is anyway impossible to prove lack of *any* problem.
> 
> Having said that, lets look into an example in
> Documentation/circular-buffers.txt:

> 
> We can see that authors of the document didn't put any memory barrier

Note that both documents have the same author list ;-)

Anyway, I didn't know about the circular thing, I suppose I should use
CIRC_SPACE() thing :-)