RFR: 8334147: Shenandoah: Avoid taking lock for disabled free set logging [v2]

[William Kemper]

> Not clean. Backport to only take lock for logging when log level is enabled.

William Kemper has updated the pull request incrementally with one additional commit since the last revision:

  Update generational mode to use log status under lock

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

Changes:
  - all: https://git.openjdk.org/shenandoah-jdk21u/pull/113/files
  - new: https://git.openjdk.org/shenandoah-jdk21u/pull/113/files/38ca9a85..d4ee79ea

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=113&range=01
 - incr: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=113&range=00-01

  Stats: 14 lines in 1 file changed: 0 ins; 5 del; 9 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/113.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/113/head:pull/113

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/113