On Mon, 4 Nov 2024 11:32:12 GMT, Maurizio Cimadamore <mcimadam...@openjdk.org> wrote:
>> I'm dubious about this. Typically these modes work in a symmetric way - if >> you `setOpaque` you need to `getOpaque`. From >> [this](https://gee.cs.oswego.edu/dl/html/j9mm.html): >> >>> Opaque mode, obtained using VarHandle getOpaque and setOpaque, adds >>> constraints over Plain mode that provide minimal awareness of a variable >>> that is subject to interthread access, **when all accesses use Opaque (or >>> stronger) mode** > >> I'm dubious about this. > > NVM, I see it now -`sharedSessionAlreadyAcquired` uses a `getVolatile` (which > has stronger semantics), so we're in the clear. `checkValidStateRaw` synchronizes with `justClose` using handshakes so an opaque or higher load is only needed in `sharedSessionAlreadyClosed`. A `getOpaque` would probably be adequate. But I believe there is no formal restriction preventing the load from being hoisted out of the loop, so I decided to go for the strongest ordering in this exception-throwing case. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/21810#discussion_r1827717654
