On Mon, 6 Jan 2025 05:00:01 GMT, David Holmes <dhol...@openjdk.org> wrote:
> In case my comment within the existing conversations gets missed I will > re-state that I don't think you need any new "is bootstrapping" logic because > you can just use `Threads::number_of_threads() > 0` to tell you if you need > to acquire the NMT lock. Though that assumes that the `WatcherThread` does > not use NMT ... but in that case you can use `WatcherThread::watcher_thread() > != nullptr` as the bootstrap condition instead. I think that the `WatcherThread` does use NMT (at least upon starting), since `Thread::call_run() ` calls `register_thread_stack_with_NMT()`. However, it looks like `WatcherThread::stop()` is called early in `before_exit` -- after which point NMT can still be used. So checking `WatcherThread::watcher_thread() != nullptr` may not work in this case as it could be set back to nullptr too early. Another solution might be to introduce something like `Threads::is_single_threaded()` which checks for `WatcherThread`, `Threads::number_of_threads()`, and any other threads that fall outside this set. I'm not sure whether that would be better than the current approach. ------------- PR Comment: https://git.openjdk.org/jdk/pull/22745#issuecomment-2573756615
