Re: [RFC PATCH] docs/memory-barriers.txt: Rewrite "KERNEL I/O BARRIER EFFECTS" section

[Will Deacon]

On Mon, Feb 11, 2019 at 12:22:18PM -0800, Paul E. McKenney wrote:
> On Mon, Feb 11, 2019 at 05:29:48PM +0000, Will Deacon wrote:
> > The "KERNEL I/O BARRIER EFFECTS" section of memory-barriers.txt is vague,
> > x86-centric, out-of-date, incomplete and demonstrably incorrect in places.
> > This is largely because I/O ordering is a horrible can of worms, but also
> > because the document has stagnated as our understanding has evolved.
> > 
> > Attempt to address some of that, by rewriting the section based on
> > recent(-ish) discussions with Arnd, BenH and others. Maybe one day we'll
> > find a way to formalise this stuff, but for now let's at least try to
> > make the English easier to understand.
> > 
> > Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxx>
> > Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> > Cc: Arnd Bergmann <arnd@xxxxxxxx>
> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > Cc: Andrea Parri <andrea.parri@xxxxxxxxxxxxxxxxxxxx>
> > Cc: Daniel Lustig <dlustig@xxxxxxxxxx>
> > Cc: David Howells <dhowells@xxxxxxxxxx>
> > Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> > cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
> 
> Hello, Will,
> 
> The intent is to replace commit 3f305018dcf3 ("docs/memory-barriers.txt:
> Enforce heavy ordering for port I/O accesses"), correct?  Either way is
> fine, just guessing based on the conflicts when applying this one.  ;-)

Yup, I decided to abandon the old patch:

http://lkml.kernel.org/r/20190211153043.GC32385@xxxxxxxxxxxxxxxxxxxxxxxxx

Thanks,

Will