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

[Thomas Stüfe]

On Tue, Jun 12, 2018 at 4:58 PM,  <coleen.phillimore at oracle.com> wrote:
>
> This change looks very useful.
>

:) Thanks!

> http://cr.openjdk.java.net/~stuefe/webrevs/8203343-VM.metaspace-show-reflection-invocation-targets/webrev.00/webrev/src/hotspot/share/oops/reflectionAccessorImplKlassHelper.hpp.html
>
> Can you have a forward declaration of InstanceKlass and Klass and not
> include instanceKlass.hpp ?  I don't need to see an additional webrev for
> this change.
>

Sure.

> Otherwise, this looks good.  Thank you for removing (now) unnecessary
> includes in
>
> http://cr.openjdk.java.net/~stuefe/webrevs/8203343-VM.metaspace-show-reflection-invocation-targets/webrev.00/webrev/src/hotspot/share/memory/metaspace/printMetaspaceInfoKlassClosure.cpp.udiff.html
>
> Thanks,
> Coleen
>
>

Thank you for the review,

..Thomas

> On 6/12/18 1:36 AM, Thomas Stüfe wrote:
>>
>> Ping.
>>
>> jdk-submit tests came back clean.
>>
>> Thanks, Thomas
>>
>> On Wed, Jun 6, 2018 at 6:05 PM, Thomas Stüfe <thomas.stuefe at gmail.com>
>> 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
>
>