Re: perf events ring buffer memory barrier on powerpc

From: Paul E. McKenney
Date: Wed Oct 30 2013 - 05:27:38 EST

On Mon, Oct 28, 2013 at 10:58:58PM +0200, Victor Kaplansky wrote:
> Oleg Nesterov <oleg@xxxxxxxxxx> wrote on 10/28/2013 10:17:35 PM:
> > mb(); // XXXXXXXX: do we really need it? I think yes.
> Oh, it is hard to argue with feelings. Also, it is easy to be on
> conservative side and put the barrier here just in case.
> But I still insist that the barrier is redundant in your example.

If you were to back up that insistence with a description of the orderings
you are relying on, why other orderings are not important, and how the
important orderings are enforced, I might be tempted to pay attention
to your opinion.

Thanx, Paul

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