Re: Unlock-lock questions and the Linux Kernel Memory Model

[Paul E. McKenney]

On Thu, Nov 30, 2017 at 05:25:01PM +0100, Peter Zijlstra wrote:
> On Thu, Nov 30, 2017 at 08:14:01AM -0800, Paul E. McKenney wrote:
> > > (Also, technically speaking, the litmus test doesn't have any release 
> > > operations, so no release sequence...)
> > 
> > True!  But if you translated it into C11, you would probably turn the
> > smp_wmb() followed by write into a store release, which would get you
> > a release sequence.
> 
> 	smp_wmb()
> 	WRITE_ONCE(*y, 1);
> 
> does not a RELEASE make.

Agreed, but it also does not C11 make.  There is no pure write barrier
in C11.

							Thanx, Paul