RFR: 8373118: Test java/lang/Thread/virtual/Starvation.java timed out [v5]

[Viktor Klang]

On Sun, 14 Dec 2025 13:06:46 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:
> 
>   Adjust runworker for previous update

src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java line 1865:

> 1863:             long ac = (c + RC_UNIT) & RC_MASK, nc;
> 1864:             int sp = (int)c, i = sp & SMASK;
> 1865:             if ((short)(c >>> RC_SHIFT) >= pc)

I'm wondering if it might make sense to re-read `parallelism` on each new loop, since if we have a parallelism resize *during this loop* we want to exit early?


Suggestion:

        for (long c = ctl;;) {
            WorkQueue[] qs = queues;
            long ac = (c + RC_UNIT) & RC_MASK, nc;
            int sp = (int)c, i = sp & SMASK, pc;
            if ((short)(c >>> RC_SHIFT) >= (pc = parallelism))

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PR Review Comment: https://git.openjdk.org/jdk/pull/28797#discussion_r2619038375