RFR 8207778: Add locking to ModuleEntry and PackageEntry tables

[Harold David Seigel]

Thanks Coleen!

Harold


On 8/9/2018 3:11 PM, coleen.phillimore at oracle.com wrote:
>
> I think this looks really good.  Thank you for making this change!
> Coleen
>
> On 8/9/18 2:10 PM, Harold David Seigel wrote:
>> Hi,
>>
>> Please review this fix for JDK-8207778.  Instead of adding additional 
>> and unneeded locking to the ModuleEntry and PackageEntry tables, the 
>> ClassLoaderDataGraph unloading code was restructured to simplify 
>> changing SystemDictionary::do_unloading() to safely scan these tables 
>> either by taking a lock or during a safepoint.
>>
>> Also, asserts for other tables scanned by 
>> SystemDictionary::do_unloading() were changed from requiring a 
>> safepoint to requiring either a lock or a safepoint.
>>
>> Open Webrev: http://cr.openjdk.java.net/~hseigel/bug_8207778/webrev/
>>
>> JBS Bug:  https://bugs.openjdk.java.net/browse/JDK-8207778
>>
>> This fix was regression tested by running Mach5 tiers 1 and 2 tests 
>> and builds on Linux-x64, Windows, and Mac OS X, running tiers 3-5 
>> tests on Linux-x64, and by running JCK-11 API, Lang and VM tests on 
>> Linux-x64.
>>
>> Thanks, Harold
>>
>