On Thu, 27 Aug 2026 09:27:18 GMT, Axel Boldt-Christmas <[email protected]> wrote:
>> Historically we have had displaced markWord's because locking (stack locks, >> and inflated monitors). >> >> After the `UseObjectMonitorTable` removal there are no more need to protect >> against displaced markWords. >> >> I suggest we simplify this logic and clean up the interface w.r.t. >> `identity_hash`. >> >> Changes the `fast_no_hash_check` and `has_no_hash` into `has_identity_hash` >> and `has_hash` checks. >> As before it is invalid to read the hash on marked objects, added asserts to >> ensure this. >> Rewrote `oopDesc::slow_identity_hash` to not regenerate a new hash every >> time it transiently fails to install the hash in the markWord due to some >> other header change. >> >> There are a few places which right now calls `identity_hash` from develop >> logging / introspection printing `InstanceStackChunkKlass::print_chunk` and >> `Continuation::print`. It is a bit unfortunate that we have these >> side-effects in debug VMs. But think we should handle these in a future RFE. >> >> Testing (in progress): >> * Tier 1-3 Oracle supported platforms >> * GHA >> >> --------- >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > Axel Boldt-Christmas has updated the pull request incrementally with two > additional commits since the last revision: > > - Use is_valhalla_enable instead of enable_preview > - Add newline to comment The AOT changes look good to me. There's duplication between the mapped and streamed versions of the updating code, but I will try to clean that up in a separate RFE. ------------- Marked as reviewed by iklam (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/32535#pullrequestreview-5043950787
