On Fri, 5 Nov 2021 21:54:01 GMT, Coleen Phillimore <cole...@openjdk.org> wrote:
>> I've written up a rather long analysis about how the use of >> `JvmtiThreadState_lock` >> in `JvmtiEventControllerPrivate::recompute_enabled()` means that we can >> safely >> traverse the JvmtiThreadState list returned by `JvmtiThreadState::first()` >> without >> racing with an exiting JavaThread. I've sent it to you via direct email. >> >> I could amend the comment above the ThreadsListHandle like this: >> >> // If we have a JvmtiThreadState, then we've reached the point where >> // threads can exist so create a ThreadsListHandle to protect them. >> // The held JvmtiThreadState_lock prevents exiting JavaThreads from >> // being removed from the JvmtiThreadState list we're about to walk >> // so this ThreadsListHandle exists just to satisfy the lower level >> sanity >> // checks that the target JavaThreads are protected. >> ThreadsListHandle tlh; > > Yes, this comment is good and it does explain why it's safe and why the TLH > is there. Thanks for doing the deep dive and explanation. Updated comment has been pushed to this PR. ------------- PR: https://git.openjdk.java.net/jdk/pull/4677
