RFR: 8304074: [JMX] Add an approximation of total bytes allocated on the Java heap by the JVM [v5]

[Paul Hohensee]

On Tue, 9 May 2023 14:21:05 GMT, Volker Simonis <simonis at openjdk.org> wrote:

>> @dcubed-ojdk This is the current thread acting on itself
>
> This method (i.e. `ThreadService::remove_thread()`) is called from `Threads::remove()` *after* the thread was removed from the thread list:
> 
> void Threads::remove(JavaThread* p, bool is_daemon) {
>   ...
>     // Maintain fast thread list
>     ThreadsSMRSupport::remove_thread(p);
>     ...
>     ThreadService::remove_thread(p, is_daemon);
> 
> 
> But if we reach here from `JavaThread::cleanup_failed_attach_current_thread()` as the comment implies (`JavaThread::cleanup_failed_attach_current_thread()` calls `Threads::remove()` in the case of an attach failure), calling `ThreadService::incr_exited_allocated_bytes()` is probably irrelevant, because a thread which failed to attach can't allocate anyway.
> 
> So instead of doing the call to `ThreadService::incr_exited_allocated_bytes()` here you can do it unconditionally and move it up before the check for `is_hidden_thread()`. This would then also account for regular thread exits where you arrive here from `JavaThread::exit()` and make the call to `ThreadService::incr_exited_allocated_bytes()` in `ThreadService::current_thread_exiting()` obsolete (also see my comment there).

Done.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13814#discussion_r1192495985