8337994: [REDO] Native memory leak when not recording any events

[bulasevich]

(not a clean backport)
Reworked to avoid https://github.com/openjdk/jdk/pull/17328/files backport

Functional jtreg1-3 tests are Ok.
Manual testing: the reproducer shows the problem is fixed with the change (see comments below)

---

Progress

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• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8337994 needs maintainer approval

Issue

• JDK-8337994: [REDO] Native memory leak when not recording any events (Bug - P3 - Requested)

Reviewers

• Paul Hohensee (@phohensee - Reviewer)

Reviewing

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$ git checkout pull/1095

Update a local copy of the PR:
$ git checkout pull/1095
$ git pull https://git.openjdk.org/jdk21u-dev.git pull/1095/head

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[bridgekeeper]

👋 Welcome back bulasevich! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[phohensee]

Just a context difference in jfrTypeSet.cpp. Lgtm.

[openjdk]

⚠️ @bulasevich This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[mlbridge]

Webrevs

• 00: Full (bf98d3a5)

[bulasevich]

Reproducer:

import jdk.jfr.consumer.RecordingStream;

/**
  * Stress test to provoke the memory leak:
  * starts 1M empty threads in VM with jfr recording
  */
public class PinnedThreadTracker implements AutoCloseable
{
    private final RecordingStream recordingStream;

    public PinnedThreadTracker() {
        recordingStream = new RecordingStream();
        recordingStream.startAsync();
        System.out.println("start recording..");
    }

    @Override
    public void close() {
        recordingStream.close();
    }

    class MyThread extends Thread {
        public void run() {
        }
    }
    public void runThreads() {
        for (int i = 0; i < 100; i++) {
            for (int j = 0; j < 100; j++) {
                for (int k = 0; k < 100; k++) {
                    new MyThread().start();
                }
                MyThread thr = new MyThread(); thr.start();
                try {
                    thr.join();
                } catch (Exception ex) {}
            }
            System.out.print(".");
        }
    }

    public static void main(String a[]) {
        PinnedThreadTracker ptt = new PinnedThreadTracker();
        ptt.runThreads();
        ptt.close();
    }
}	

Manual testing results on jdk21u:

$ for i in {0..60}; do
    export PID=`ps -ax | grep java | grep PinnedThreadTracker | sed "s/^ *// ; s/ .*//"`
    jcmd $PID VM.native_memory | grep Tracing.*reserved
    sleep 1s
  done

Before the change (jcmd VM.native_memory output once a second):
-                   Tracing (reserved=17355KB, committed=17355KB)
-                   Tracing (reserved=21646KB, committed=21646KB)
-                   Tracing (reserved=25870KB, committed=25870KB)
-                   Tracing (reserved=30065KB, committed=30065KB)
...
-                   Tracing (reserved=240567KB, committed=240567KB)
-                   Tracing (reserved=244519KB, committed=244519KB)
-                   Tracing (reserved=248525KB, committed=248525KB)
-                   Tracing (reserved=252527KB, committed=252527KB)

With the fix:
-                   Tracing (reserved=17655KB, committed=17655KB)
-                   Tracing (reserved=18125KB, committed=18125KB)
-                   Tracing (reserved=18449KB, committed=18449KB)
-                   Tracing (reserved=18961KB, committed=18961KB)
...
-                   Tracing (reserved=17443KB, committed=17443KB)
-                   Tracing (reserved=17958KB, committed=17958KB)
-                   Tracing (reserved=18491KB, committed=18491KB)
-                   Tracing (reserved=18970KB, committed=18970KB)

[bulasevich]

/approval request
The change fixes jfr memory leak. We need that in jdk21.

[openjdk]

@bulasevich
8337994: The approval request has been created successfully.

[GoeLin]

Hi @bulasevich, can this wait for the April update? It would get some more test coverage.

[bulasevich]

Hi @bulasevich, can this wait for the April update? It would get some more test coverage.

Hi @GoeLin
In my opinion, this bug could have a significant impact on customers, and it would be ideal to fix it as soon as possible. However, I understand that some reasonable patience is necessary. I'm not opposed to waiting for the next update.