RFR(s): 8203343: VM.{metaspace|classloaders|classhierarchy...} jcmd should show invocation targets for Generated{Method|Constructor}AccessorImpl classes

[Thomas Stüfe]

Oh, copy paste error. I’ll correct that. Thanks, Coleen!

On Wed 13. Jun 2018 at 21:42, <coleen.phillimore at oracle.com> wrote:

>
>
> http://cr.openjdk.java.net/~stuefe/webrevs/8203343-VM.metaspace-show-reflection-invocation-targets/webrev.01/webrev/test/hotspot/jtreg/serviceability/dcmd/vm/ShowReflectionTargetTest.java.html
>
> Minor comment in copyright date.  Since it's a new test, it doesn't need
> 2014 as a start date.
>
> Otherwise, looks good.
> Thanks,
> Coleen
>
> On 6/13/18 6:32 AM, Thomas Stüfe wrote:
> > Hi Serguei,
> >
> > thank you for your review!
> >
> > You are right, a regression test makes sense here. I wrote one. See
> > updated webrev (only added the test, nothing else did change):
> >
> >
> http://cr.openjdk.java.net/~stuefe/webrevs/8203343-VM.metaspace-show-reflection-invocation-targets/webrev.01/webrev/
> >
> > I am re-running the jdk-submit tests.
> >
> > Thanks & Best Regards, Thomas
> >
> > On Tue, Jun 12, 2018 at 11:01 PM, serguei.spitsyn at oracle.com
> > <serguei.spitsyn at oracle.com> wrote:
> >> Hi Thomas,
> >>
> >> It looks good to me.
> >> But I'm not an expert in the area of Generated Accessors.
> >>
> >> How was this tested?
> >> Does it make sense to add a unit test for this?
> >>
> >> Thanks,
> >> Serguei
> >>
> >>
> >>
> >> On 6/6/18 09:05, Thomas Stüfe wrote:
> >>> Dear all,
> >>>
> >>> may I please have feedback and if possible reviews for this small
> >>> addition:
> >>>
> >>> CR: https://bugs.openjdk.java.net/browse/JDK-8203343
> >>> Webrev:
> >>>
> http://cr.openjdk.java.net/~stuefe/webrevs/8203343-VM.metaspace-show-reflection-invocation-targets/webrev.00/webrev/
> >>>
> >>> (Note: this patch goes atop of
> >>> https://bugs.openjdk.java.net/browse/JDK-8203682, which is currently
> >>> up for RFR).
> >>>
> >>> ---
> >>>
> >>> When analyzing situations involving a lot of reflection, one often
> >>> stares at walls of "GeneratedXXXAccessorXXX" classes. These names are
> >>> generated and not at all helpful in analyzing the problem (e.g. which
> >>> component in a server node does this much reflection and hence uses so
> >>> much metaspace).
> >>>
> >>> This patch adds the ability to print out invocation targets
> >>> additionally to class names if the class is a generated accessor - for
> >>> now this ability has been added to VM.metaspace, VM.classloaders and
> >>> VM.class_hierarchy.
> >>>
> >>> Example output from "VM.class_hierarchy":
> >>>
> >>> <snip>
> >>> |--jdk.internal.reflect.MagicAccessorImpl/null
> >>> <snip>
> >>> |  |--jdk.internal.reflect.ConstructorAccessorImpl/null
> >>> |  |
> >>>
> |--jdk.internal.reflect.GeneratedConstructorAccessor18/0x00007f9ee8350c10
> >>> (invokes:
> >>>
> org/springframework/boot/context/properties/ConfigurationPropertiesBindingPostProcessorRegistrar::<init>
> >>> ()V)
> >>> |  |
> >>>
> |--jdk.internal.reflect.GeneratedConstructorAccessor17/0x00007f9ee8349c00
> >>> (invokes:
> >>>
> org/springframework/boot/context/properties/EnableConfigurationPropertiesImportSelector$ConfigurationPropertiesBeanRegistrar::<init>
> >>> ()V)
> >>> <snip>
> >>> |  |--jdk.internal.reflect.MethodAccessorImpl/null
> >>> |  |
> |--jdk.internal.reflect.GeneratedMethodAccessor23/0x00007f9ec8329b60
> >>> (invokes: org/apache/tomcat/util/modeler/AttributeInfo::setIs (Z)V)
> >>> |  |
> |--jdk.internal.reflect.GeneratedMethodAccessor22/0x00007f9ee831bc70
> >>> (invokes:
> >>> org/springframework/boot/autoconfigure/SpringBootApplication::exclude
> >>> ()[Ljava/lang/Class;)
> >>> <snip>
> >>>
> >>> See here more examples:
> >>>
> >>> "VM.class_hierarchy"
> >>>
> >>>
> http://cr.openjdk.java.net/~stuefe/webrevs/8203343-VM.metaspace-show-reflection-invocation-targets/example-VM.class_hierarchy.txt
> >>>
> >>> "VM.classloaders show-classes"
> >>>
> >>>
> http://cr.openjdk.java.net/~stuefe/webrevs/8203343-VM.metaspace-show-reflection-invocation-targets/example-VM.classloaders.txt
> >>>
> >>>
> >>> ----
> >>>
> >>> Note: I am not sure if this is a fit for hotspot-runtime or
> >>> serviceability. Sorry for crossposting.
> >>>
> >>> Thank you,
> >>>
> >>> Thomas
> >>
>
>