RFR: 8308881: Strong CLD oop handle roots are demoted to non-roots concurrently

[Erik Österlund]

On Thu, 25 May 2023 16:20:57 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> Could this be using CollectedHeap::keep_alive instead of performing this clear/store dance?

No, because the problem isn't keeping the object alive. It's already kept alive using handles. The problem is that the snapshot of strong roots are not processed during marking, leading to ABA problems, causing things to go wrong later on. Therefore I wanted to model the solution conceptually as close as possible to other handles. Admittedly, it does look more like an exptic rain dance than ideal. Just got to clap our hands, spin around 360 degrees and then jump - then clap our hands again!

-------------

PR Comment: https://git.openjdk.org/jdk/pull/14154#issuecomment-1563275336