RFR(S) 8208658: Make CDS archived heap regions usable even if compressed oop encoding has changed

[Lindenmaier, Goetz]

... I figured there is GC.Z.isSupported(), which just does what I need, and 
what you proposed, Ioi.

See also 
http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2018-August/029865.html

Best regards,
  Goetz.

> -----Original Message-----
> From: Lindenmaier, Goetz
> Sent: Freitag, 31. August 2018 09:41
> To: 'Ioi Lam' <ioi.lam at oracle.com>; Jiangli Zhou <jiangli.zhou at oracle.com>;
> Thomas Schatzl <thomas.schatzl at oracle.com>; hotspot-runtime-
> dev at openjdk.java.net runtime <hotspot-runtime-dev at openjdk.java.net>;
> hotspot-gc-dev <hotspot-gc-dev at openjdk.java.net>
> Subject: RE: RFR(S) 8208658: Make CDS archived heap regions usable even if
> compressed oop encoding has changed
> 
> Hi Ioi, Jinagli,
> 
> Thanks for your feedback! I will look into this and post a webrev.
> I'll open a bug myself.
> 
> Best regards
>   Goetz.
> 
> > -----Original Message-----
> > From: Ioi Lam <ioi.lam at oracle.com>
> > Sent: Mittwoch, 29. August 2018 19:05
> > To: Jiangli Zhou <jiangli.zhou at oracle.com>; Lindenmaier, Goetz
> > <goetz.lindenmaier at sap.com>; Thomas Schatzl
> > <thomas.schatzl at oracle.com>; hotspot-runtime-dev at openjdk.java.net
> > runtime <hotspot-runtime-dev at openjdk.java.net>; hotspot-gc-dev
> > <hotspot-gc-dev at openjdk.java.net>
> > Subject: Re: RFR(S) 8208658: Make CDS archived heap regions usable even
> if
> > compressed oop encoding has changed
> >
> > How about creating a general purpose WB API that can query for all the
> > SupportedGCs[] defined in src/hotspot/share/gc/shared/gcConfig.cpp?
> >
> > Thanks
> >
> > - Ioi
> >
> >
> > On 8/29/18 9:43 AM, Jiangli Zhou wrote:
> > > Hi Goetz,
> > >
> > > Adding WB_IsZGCIncludedInVmBuild() in whitebox sounds good. It might
> > > be useful in other cases as well. Have you filed a bug for the
> > > sharedStrings/IncompatibleOptions.java issue? If not, I can create one.
> > >
> > > Thanks,
> > >
> > > Jiangli
> > >
> > >
> > > On 8/29/18 1:18 AM, Lindenmaier, Goetz wrote:
> > >> Hi,
> > >>
> > >> I see appcds/sharedStrings/IncompatibleOptions.java failing since it
> > >> was pushed. Now two more tests for this were added in 8208658.
> > >>
> > >> They fail because we build on linuxx86_64 without ZGC, but the test
> > >> contains
> > >> if (Platform.isLinux() && Platform.isX64()) {
> > >>              testDump(1, "-XX:+UnlockExperimentalVMOptions",
> > >> "-XX:+UseZGC", COOPS_DUMP_WARNING, true);
> > >> }
> > >>
> > >> Should we implement WB_IsZGCIncludedInVmBuild() similar to
> > >> WB_IsCDSIncludedInVmBuild()
> > >> in whitebox?  This could be used instead.
> > >> Or is there already functionality to test this better than checking
> > >> the platforms?
> > >>
> > >> Best regards,
> > >>    Goetz.
> > >>
> > >>
> > >>
> > >>> -----Original Message-----
> > >>> From: hotspot-gc-dev <hotspot-gc-dev-bounces at openjdk.java.net>
> On
> > >>> Behalf Of Ioi Lam
> > >>> Sent: Mittwoch, 22. August 2018 17:30
> > >>> To: Thomas Schatzl <thomas.schatzl at oracle.com>; Jiangli Zhou
> > >>> <jiangli.zhou at oracle.com>; hotspot-runtime-dev at openjdk.java.net
> > >>> runtime <hotspot-runtime-dev at openjdk.java.net>; hotspot-gc-dev
> > >>> <hotspot-gc-dev at openjdk.java.net>
> > >>> Subject: Re: RFR(S) 8208658: Make CDS archived heap regions usable
> > >>> even if
> > >>> compressed oop encoding has changed
> > >>>
> > >>> Thanks Thomas. I've fixed the comment, did more hs-tier1-3 testing to
> > >>> validate the patch, and pushed.
> > >>>
> > >>> - Ioi
> > >>>
> > >>> On 8/22/18 1:32 AM, Thomas Schatzl wrote:
> > >>>> Hi Ioi,
> > >>>>
> > >>>> On Tue, 2018-08-21 at 10:38 -0700, Ioi Lam wrote:
> > >>>>> Hi Thomas.
> > >>>>>
> > >>>>> Thanks for the review. I've updated the webrev according to your
> > >>>>> comments. See
> > >>>>>
> > >>>>> http://cr.openjdk.java.net/~iklam/jdk12/8208658-relocate-
> archived-
> > hea
> > >>>>> p-regions.v03.delta/
> > >>>>>
> > >>>>     looks good sans Jiangli's comment about that log message. I do not
> > >>>> need to see a new webrev for that change either.
> > >>>>
> > >>>> Thanks,
> > >>>>     Thomas
> > >>>>
> > >