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 x86-centric, out-of-date, incomplete and demonstrably incorrect in places.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