RFR (S) 8213107: Make ClassLoaderDataGraph iterator skip unloaded CLDs

[Erik Österlund]

Hi Coleen,

Looks good.

Thanks,
/Erik

On 2018-10-30 14:25, coleen.phillimore at oracle.com wrote:
> Summary: with concurrent class unloading, the CLDG could contain 
> unloaded CLDs while iterating in a safepoint
>
> This fixes the parallel class loading tests (which unfortunately 
> aren't in the open tests) with concurrent class unloading. 
> Redefinition was iterating through the CLDG and barfing on unloaded 
> classes.
>
> Tested with pcl tests, test/hotspot/jtreg/runtime, jfr tests, and 
> test/hotspot/jtreg/vmTestbase/nsk which includes jvmti and jdi 
> tests.   These things iterate through CLDG.
>
> open webrev at http://cr.openjdk.java.net/~coleenp/8213107.01/webrev
> bug link https://bugs.openjdk.java.net/browse/JDK-8213107
>
> Thanks,
> Coleen