RFR(xs): 8247252: TestCombinedCompressedFlags.java failed src/hotspot/share/services/virtualMemoryTracker.cpp:388 Error: ShouldNotReachHere()

[Thomas Stüfe]

Thanks Dan for the information.

..Thomas

On Wed, Jun 10, 2020 at 5:52 PM Daniel D. Daugherty <
daniel.daugherty at oracle.com> wrote:

> > The reason we did not see these errors before in our (SAPs) CI was that
> we
> > run our tests with NMT (by default) switched off. Apparently Oracle runs
> > the jtreg tests with NMT enabled via -vmoptions? We will change our CI to
> > do this too. But it would be good if the test flags would be published
> > somewhere, and we would all use the same flags.
>
> This failure first showed up in our Tier4 testing. It looks like
> that tier's task definition includes these options:
>
> -XX:+UnlockDiagnosticVMOptions -XX:ArchiveRelocationMode=1
> -Xlog:cds=debug -XX:NativeMemoryTracking=detail
>
>
> The task itself is named: tier4-rt-cds-relocation.
>
> I don't know if there are plans to publish the tiered testing
> task definitions.
>
> Dan
>
>
> On 6/10/20 9:09 AM, Thomas Stüfe wrote:
> > Hi all,
> >
> > could I please have reviews for this bug fix.
> >
> > JBS: https://bugs.openjdk.java.net/browse/JDK-8247252
> > webrev:
> >
> http://cr.openjdk.java.net/~stuefe/webrevs/8247252-cds-nmt-ccps-off/webrev.00/webrev/
> >
> > This bug was introduced with "8243535 NMT may show wrong numbers for CDS
> > and CCS".
> >
> > The error is that a VM loading a shared archive but having compressed
> class
> > pointers disabled would reserve space for the CDS but fail to register it
> > with the correct tag with NMT. So, inside NMT it still is marked as
> > "mtUnknown". This leads to a follow up error when the actual archive
> files
> > are to be mapped into this reserved region, since the region is expected
> to
> > carry the "mtClassShared" tag for this to work.
> >
> > The fix is simple to add the missing registration in metaspaceShared.cpp
> > when the cds has been reserved for the non-class-space case:
> >
> > @@ -2469,10 +2470,12 @@
> >       archive_space_rs = ReservedSpace(archive_space_size,
> > archive_space_alignment,
> >                                        false /* bool large */,
> > (char*)base_address);
> >       if (archive_space_rs.is_reserved()) {
> >         assert(base_address == NULL ||
> >                (address)archive_space_rs.base() == base_address,
> "Sanity");
> > +      // Register archive space with NMT.
> > +      MemTracker::record_virtual_memory_type(archive_space_rs.base(),
> > mtClassShared);
> >         return archive_space_rs.base();
> >       }
> >       return NULL;
> >     }
> >
> > All the rest is fluff:
> >
> > - added logging in a number of places to make analysis of these kinds of
> > errors simpler
> > - explicitly switched on NMT for a number of cds jtreg tests.
> >
> > ---
> >
> > The reason we did not see these errors before in our (SAPs) CI was that
> we
> > run our tests with NMT (by default) switched off. Apparently Oracle runs
> > the jtreg tests with NMT enabled via -vmoptions? We will change our CI to
> > do this too. But it would be good if the test flags would be published
> > somewhere, and we would all use the same flags.
> >
> > Thanks, Thomas
>
>