RFR(xs): 8225200: runtime/memory/RunUnitTestsConcurrently.java has a memory leak

[Thomas Stüfe]

Thanks Stefan!

On Mon, Jul 1, 2019, 21:06 Stefan Karlsson <stefan.karlsson at oracle.com>
wrote:

> On 2019-07-01 20:56, Thomas Stüfe wrote:
> > Hi all,
> >
> > may I please have reviews and opinions about the following patch:
> >
> > Issue: https://bugs.openjdk.java.net/browse/JDK-8227041
> > cr:
> >
> http://cr.openjdk.java.net/~stuefe/webrevs/8227041-rununittestsconcurrently-has-a-mem-leak/webrev.00/webrev/index.html
> >
> > There is a memory leak in test_virtual_space_list_large_chunk(), called
> as
> > part of the whitebox tests WB_RunMemoryUnitTests(). In this test
> metaspace
> > allocation is tested by rapidly allocating and subsequently leaking a
> > metachunk of ~512K. This is done by a number of threads in a tight loop
> for
> > 15 seconds, which usually makes for 10-20GB rss. Test is usually OOM
> killed.
> >
> > This test seems to be often excluded, which makes sense, since this leak
> > makes its memory usage difficult to predict.
> >
> > It is also earmarked by Oracle for gtest-ification, see 8213269.
> >
> > This leak is not easy to fix, among other things because it is not clear
> > what it is it wants to test. Meanwhile, time moved on and we have quite
> > nice gtests to test metaspace allocation (see e.g.
> > test_metaspace_allocation.cpp) and I rather would run those gtests
> > concurrently. Which could be a future RFE.
> >
> > So I just removed this metaspace related test from
> WB_RunMemoryUnitTests()
> > altogether, since to me it does nothing useful. Once you remove the
> leaking
> > allocation, not much is left.
> >
> > Without this part RunUnitTestsConcurrently test runs smoothly through its
> > other parts, and in that form it is still useful.
> >
> > What do you think?
>
> I think this makes sense and it looks good to me.
>
> Thanks,
> StefanK
>
> >
> > Cheers, Thomas
>
>