[jdk17u-dev] RFR: 8288663: JFR: Disabling the JfrThreadSampler commits only a partially disabled state

[Dmitry Chuyko]

On 17u JFR sometimes continues to sample threads after recordings are closed. In particular that happens on Linux aarch64 when JFR streaming is used and only jdk.ExecutionSample event is enabled. Symptoms:


[76.403s][debug][jfr      ] Recording "Recording Stream: 2023-11-21T14:57:07.651509569Z" (2) added chunk /tmp/2023_11_21_14_56_06_9044/2023_11_21_14_57_07.jfr, current size=4397790
[76.404s][trace][jfr      ] Disenrolling thread sampler
[76.404s][trace][jfr      ] Enrolling thread sampler
[76.404s][trace][jfr      ] Updated thread sampler for java: 1  ms, native 0 ms


This fix cures that enrolling after disenrolling. I'm not sure if related JDK-8295274 should be backported as well.

The patch was mostly applied cleanly but few hunks were replicated by hand without changes in their code.

Testing: tier1, tier2, jdk_jfr, gc/stress/jfr on (linux-aarch64 fastdebug).

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

Commit messages:
 - Backport a7df5a40639a4d3138616c9fc1b144381240d2e5

Changes: https://git.openjdk.org/jdk17u-dev/pull/1986/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1986&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8288663
  Stats: 121 lines in 7 files changed: 47 ins; 18 del; 56 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1986.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1986/head:pull/1986

PR: https://git.openjdk.org/jdk17u-dev/pull/1986