review request (M): 7121140: Allocation paths require explicit memory synchronization operations for RMO systems

[Roland Westrelin]

> I think the instruct name should be membar_storestoree instead of unnecessary_membar_storestore and remove the "unnecessary so" part of the comment.  It's like membar_release where it's necessary but it never emits any assembly.

Makes sense. I'll change that before I push it.

> I wouldn't expect this to affect performance since it's not emitting an extra instructions but we are emitting some extra barriers which tangles of the memory graph a bit.  Could you do some quick performance to make sure nothing's changed?

Ok. I'll do that. Would specjvm98 + specjbb2005 on x86 be sufficient?

> Otherwise it looks good.

Thanks for the review.

Roland.