RFR: 8364516: Serial: Move class unloading logic inside SerialFullGC::invoke_at_safepoint

Fri Aug 1 08:53:06 UTC 2025

Encapsulating classunloading logic inside `invoke_at_safepoint` and adding doc explaining why the classunloading logic can't be placed at the end of marking during full-gc, like other STW collectors.

Test: tier1-3

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Commit messages:
 - sgc-unloading-doc

Changes: https://git.openjdk.org/jdk/pull/26588/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26588&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8364516
  Stats: 27 lines in 2 files changed: 17 ins; 10 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/26588.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26588/head:pull/26588

PR: https://git.openjdk.org/jdk/pull/26588