This PR proposes to improve the performance of the newly integrated confined arena cache. Confined arenas now remember the platform pool array and the pool array index used for pool acquisition. Upon closing the arena, the pool can be returned (in most cases) directly to the correct index in the confined arena cache.
If the opportunistic pool index is occupied, the logic falls back to the regular path, which scans the array for an empty slot. The PR additionally proposes to add a test to make sure the unusual release path works correctly. --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - Strengthen test - Remember pool and pool slot Changes: https://git.openjdk.org/jdk/pull/32766/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=32766&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8391909 Stats: 119 lines in 3 files changed: 109 ins; 2 del; 8 mod Patch: https://git.openjdk.org/jdk/pull/32766.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/32766/head:pull/32766 PR: https://git.openjdk.org/jdk/pull/32766
