On Wed, 5 Apr 2023 08:37:26 GMT, David Holmes <dhol...@openjdk.org> wrote:
>> We have the strange situation where calling `t.isAlive()` on a >> `java.lang.Thread` `t`, will call into the VM (via `alive()` then >> `isAlive0()`) where the VM then examines the `eetop` field of `t` to extract >> its `JavaThread` pointer and compare it to null. We can simply read `eetop` >> directly in `Thread.alive()`: >> >> boolean alive() { >> return eetop != 0; >> } >> >> I also updated a comment in relation to `eetop`. >> >> Testing: tiers 1-3 >> >> Thanks > > David Holmes has updated the pull request incrementally with one additional > commit since the last revision: > > Test tweaks Yes, I suspect having isAlive be synchronized would have had side-effects and maybe deadlock in some cases. Volatile-read on the libs side + OrderAccess::release in the VM at termination time looks okay. ------------- Marked as reviewed by alanb (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/13287#pullrequestreview-1372446213