RFR: 8371320: runtime/ErrorHandling/PrintVMInfoAtExitTest.java fails with unexpected amount for Java Heap reserved memory

[Paul Hübner]

On Fri, 7 Nov 2025 09:11:07 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

> > It turns out that, rarely, we do reserve more memory even without asan enabled.
> 
> We only saw this with ASAN and there was an explanation why this happened. Any idea why did this occur in your tests, without ASAN ?
> 
> (otherwise the test looks okay if we really agree that this check should be relaxed)

@jsikstro and I are doing a small investigation into this, I'll keep you updated. We see that G1's reservation size is what we expect, but CDS also uses the `mtJavaHeap` tag.


> The condition of `reserved < committed` is/should be always true, otherwise NMT is not doing its tasks correctly.
> I suggest to check if the reported amount of `reserved` (and `committed` for a restricter condition) is at least 64M (which is given as options in command line).

Would it make sense to keep `reserved < committed` as a sanity check? Would you also suggest checking that `|reserved - committed| <= some_upper_bound`?

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PR Comment: https://git.openjdk.org/jdk/pull/28179#issuecomment-3501945001