On Sat, 17 Jan 2026 16:11:35 GMT, Viktor Klang <[email protected]> wrote:
>> Patricio Chilano Mateo has updated the pull request incrementally with one
>> additional commit since the last revision:
>>
>> add comment in test
>
> src/java.base/share/classes/java/lang/VirtualThread.java line 641:
>
>> 639: synchronized (timedWaitLock()) {
>> 640: byte seqNo = ++timedWaitSeqNo;
>> 641: timeoutTask = schedule(() ->
>> waitTimeoutExpired(seqNo), timeout, MILLISECONDS);
>
> Just a sidenote, I think it would be nice to see if we could eliminate the
> need for the seqNo if we were able to allocate the timeoutTask before
> submitting it, then using getAndSet or compareAndExchange to install it in
> the timeoutTask-field, and on cancellation we can CAS out it to null and only
> if we succeed we have successfully uninstalled it and can cancel it. Not high
> priority, but I find it valuable to always have an idea of how to do it
> differently. This might also make it possible to avoid having to use the
> timedWaitLock.
The seqNo is because the timeout task executes asynchronously, and can be
executing when cancelled. It reduces the potential for interference and
spurious wakeups when there is tight sequence of waits. There may be better
designs, we went through when the changes were baking in the loom repo.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/29255#discussion_r2701418098
