[Ksummit-discuss] [TECH TOPIC] Memory model, using ISO C++11 atomic ops

[Luis R. Rodriguez]

On Fri, Jul 22, 2016 at 09:44:11AM -0700, Paul E. McKenney wrote:
> On Fri, Jul 22, 2016 at 11:34:35AM +0100, David Howells wrote:
> > Earlier this year we had a discussion of the possibilities of using ISO C++11
> > atomic operations inside the kernel to implement kernel atomic ops of sorts
> > various, posted here:
> > 
> > 	Subject: [RFC PATCH 00/15] Provide atomics and bitops implemented with ISO C++11 atomics
> > 	Date: Wed, 18 May 2016 16:10:37 +0100
> > 
> > Is it worth getting together to discuss these in person in one of the tech
> > slots - especially if there are some gcc or llvm people available at plumbers
> > who could join in?
> > 
> > 
> > Further, Paul McKenney and others are assembling a memory model description.
> 
> We are attempting to automate memory-barriers.txt, so that you could
> provide fragments of C code, and the tool would tell you whether a given
> outcome happens always, sometimes, or never.  The current prototype
> handles memory accesses, memory barriers, and RCU, but not yet locking
> or read-modify-write atomics (though there is some vestigal support for
> RMW atomics).  We are currently playing whack-a-mole with odd corner cases
> of various architectures' memory models.  We are therefore also working
> on ways of handling the resulting uncertainty.  Good clean fun!  ;-)

Consider me interested in this discussion, patches, etc.

  Luis