On Wed, 5 Apr 2023 08:37:26 GMT, David Holmes <[email protected]> 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
