RFR (M): JDK-8159262: Walking PackageEntry Export and ModuleEntry Reads Must Occur Only When Neccessary And Wait Until ClassLoader's Aliveness Determined

[Zhengyu Gu]

Thanks for the changes.

PackageEntry::delete_qualified_exports() has nothing to do with class 
unloading, should it be handled in earlier loop? or it may get lost.

-Zhengyu

On 06/27/2016 04:50 PM, Lois Foltan wrote:
>
> On 6/27/2016 12:03 PM, Zhengyu Gu wrote:
>> Hi Lois,
>>
>> I have a question:
>>
>> classLoaderData.cpp # 1004 - 1013
>>
>> If there is no class loader unloaded, (for example, _unloading == 
>> NULL), do you still need to execute this purge loop?
> Hi Zhengyu,
>
> Thank you for the review.  I have addressed your concern by moving the 
> purge loop into the following conditional that only executes "if 
> (seen_dead_loader)", nice catch.  This updated webrev also contains an 
> improvement to the test ModuleStress.java to include a module defined 
> to a custom system class loader, specified via 
> -Djava.system.class.loader.
>
> http://cr.openjdk.java.net/~lfoltan/bug_jdk8159262.2/webrev/
>
> Thanks,
> Lois
>
>>
>> Thanks,
>>
>> -Zhengyu
>>
>> On 06/22/2016 10:51 AM, Lois Foltan wrote:
>>>
>>> On 6/22/2016 8:56 AM, Alan Bateman wrote:
>>>>
>>>>
>>>> On 22/06/2016 13:51, David Holmes wrote:
>>>>>
>>>>> How do you envisage any system classloader "dying" ??
>>>> The system class loader (be it the built-in application class 
>>>> loader or a custom system class loader configured via 
>>>> -Djava.system.class.loader) will/can never be GC'ed. 
>>>> ClassLoader.getSystemClassLoader() always returns a reference to it 
>>>> (for example).
>>> Ahh, ok, I was being overly cautious, so no opportunity to reset the 
>>> system class loader dynamically at all? 
>>> SystemDictionary::_java_class_loader is not initialized until after 
>>> the module system initialization is complete.  Due to this I have 
>>> updated my webrev to check for either the built-in application class 
>>> loader or a custom system class loader and have renamed the method 
>>> to is_system_class_loader().
>>>
>>> http://cr.openjdk.java.net/~lfoltan/bug_jdk8159262.1/webrev/
>>>
>>> Thanks,
>>> Lois
>>>
>>
>