[jdk21u-dev] RFR: 8309953: Strengthen and optimize oopDesc age methods

Tue Jul 8 16:46:06 UTC 2025

https://bugs.openjdk.org/browse/JDK-8309953

A clean backport. An minor optimization for oopDesc age. 

tier 1 passed locally. The logic is simple - store the `mark()` value into a var so we don't read it twice. The original commit is in tip for almost 2 years. Low risk.

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Commit messages:
 - Backport 4a5475ce0492fc02019b0f89b50601c388c63e21

Changes: https://git.openjdk.org/jdk21u-dev/pull/1950/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1950&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8309953
  Stats: 10 lines in 1 file changed: 2 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1950.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1950/head:pull/1950

PR: https://git.openjdk.org/jdk21u-dev/pull/1950