[foreign-memaccess] RFC: to scope or not to scope?

[John Rose]

On Jun 1, 2019, at 8:41 PM, John Rose <john.r.rose at oracle.com> wrote:
> 
> For example, if the root segment allows writing, then any thread can
> initiate a racy write to it.  Unless this is provably under a mutex of
> some sort, this racy write can still be "handing around" when the
> segment transitions back to the confined state.  This means that the
> confined state can suffer "hangovers" from previous states, when a
> write from that state is not yet completed.

(I meant to say "hanging around".  If you read the JMM carefully
you will be horrified to find that there are no promptness guarantees
about reads and writes, unless they are also connected with
monitors or volatile references.  Java platforms tend to commit
writes quickly, whatever that means, and report reads from fresh
data, whatever that means, but this is *not* guaranteed by the JMM.)