RFR: 8373118: Test java/lang/Thread/virtual/Starvation.java timed out [v21]

[Viktor Klang]

On Thu, 8 Jan 2026 15:18:00 GMT, Doug Lea <dl at openjdk.org> wrote:

>> Changes signal filtering to avoid possible starvation
>
> Doug Lea has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Change signalWork fencing; in-progress activation changes

src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java line 1830:

> 1828:      */
> 1829:     final void signalWork(WorkQueue q, int qbase) {
> 1830:         int pc = U.getIntAcquire(this, PARALLELISM);

I like this, as this has the nice benefit of seeing potential changes to `parallelism` sooner.

src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java line 1855:

> 1853:                 break;
> 1854:             if (c == (c = ctl) &&
> 1855:                 c == (c = U.compareAndExchangeLong(this, CTL, c, nc))) {

Are there any measurable differences between the above and `c == (c = ctl) && U.compareAndSetLong(this, CTL, c, nc)` or `c == U.compareAndExchangeLong(this, CTL, c, nc)`? 🤔

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/28797#discussion_r2673104063
PR Review Comment: https://git.openjdk.org/jdk/pull/28797#discussion_r2673100883