RFR(s): 8222015: Small VM.metaspace improvements

[Jiangli Zhou]

Hi Thomas,

This seems good to me. I have a few minor suggestions below, but please
feel free to keep your existing code without changing.

- For consistency with the existing code and VM.metaspace output, it might
be worth renaming _num_classes_cds to _num_classes_shared, and
_num_classes_cds_by_spacetype to _num_classes_shared_by_spacetype.

- src/hotspot/share/memory/metaspace/printCLDMetaspaceInfoClosure.cpp
You could replace the following MetaspaceShared::is_in_shared_metaspace(k)
call with k->is_shared() if 'k' is guaranteed to be a valid Klass.

  58   void do_klass(Klass* k) {  59     _num_classes ++;  60     if
(MetaspaceShared::is_in_shared_metaspace(k)) {  61
_num_classes_cds ++;  62     }  63   }

- src/hotspot/share/memory/metaspace/printMetaspaceInfoKlassClosure.cpp

  46   // Print a 's' for shared classes  47
_out->put(MetaspaceShared::is_in_shared_metaspace(k) ? 's': ' ');  48

Same suggestion as the above.

Thanks and regards,
Jiangli


On Fri, Apr 5, 2019 at 3:07 AM Thomas Stüfe <thomas.stuefe at gmail.com> wrote:

> Hi all,
>
> may I have please a review for this collection of small improvements to the
> VM.metaspace diagnostic command?
>
> - it clearly marks now classes whose metadata reside in cds
> - it shows the number of classes loaded, incl. those from cds, in the
> overviews too.
>
> Issue: https://bugs.openjdk.java.net/browse/JDK-8222015
> cr:
>
> http://cr.openjdk.java.net/~stuefe/webrevs/8222015--small-vm.metaspace-improvements/webrev.00/webrev/
>
> Example output:
>
> http://cr.openjdk.java.net/~stuefe/webrevs/8222015--small-vm.metaspace-improvements/example-by-spacetype.txt
>
> http://cr.openjdk.java.net/~stuefe/webrevs/8222015--small-vm.metaspace-improvements/example-showloaders.txt
>
> http://cr.openjdk.java.net/~stuefe/webrevs/8222015--small-vm.metaspace-improvements/example-showloaders-showclasses.txt
> (scroll
> down -> cds classes in <bootstrap> are now marked with 's')
>
> Thank you,
>
> Thomas
>