On Wed, Jan 27, 2016 at 02:57:07PM +0000, David Howells wrote:

Peter Zijlstra [off-list ref] wrote:

quoted

+==========
+DISCLAIMER
+==========
+
+This document is not a specification; it is intentionally (for the sake of
+brevity) and unintentionally (due to being human) incomplete. This document is
+meant as a guide to using the various memory barriers provided by Linux, but
+in case of any doubt (and there are many) please ask.
+
+I repeat, this document is not a specification of what Linux expects from
+hardware.

The purpose of this document is twofold:

 (1) to specify the minimum functionality that one can rely on for any
     particular barrier, and

 (2) to provide a guide as to how to use the barriers that are available.

Note that an architecture can provide more than the minimum requirement for
any particular barrier, but if the barrier provides less than that, it is
incorrect.

Note also that it is possible that a barrier may be a no-op for an
architecture because the way that arch works renders an explicit barrier
unnecessary in that case.

quoted

+

Can you bung an extra blank line in here if you have to redo this at all?

quoted

+========
+CONTENTS
+========
 
  (*) Abstract memory access model.

Good point!  Would you be willing to add a Signed-off-by so I
can take the combined change, assuming Peter and Will are good
with it?

							Thanx, Paul