perf events ring buffer memory barrier on powerpc

[Paul E. McKenney]

On Wed, Oct 30, 2013 at 04:51:16PM +0100, Peter Zijlstra wrote:
> 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 :-)

Interesting that we didn't seem to supply a definition...  ;-)

							Thanx, Paul