RFR (S) 8178336: Unnecessary SystemDictionary walk for Protection domain liveness

[David Holmes]

Hi Coleen,

On 11/04/2017 6:18 AM, coleen.phillimore at oracle.com wrote:
> Summary: remove system dictionary walk and pass strong closure for
> !ClassUnloading

Can't really comment on functional change but noticed this comment:

241   // Then iterate over the protection domain cache to apply the 
closure on the
  242   // previously marked ones.
  243   _pd_cache_table->oops_do(blk);

is no longer accurate: there is nothing "before" for the "then" to 
follow, and there is no previous marking done.

Thanks,
David

> See bug for more details:
>
> open webrev at http://cr.openjdk.java.net/~coleenp/8178336.01/webrev
> bug link https://bugs.openjdk.java.net/browse/JDK-8178336
>
> Tested with nightly tier2-5 tests and jprt (runs all GCs) and runThese
> with -XX:-ClassUnloading.
>
> Thanks,
> Coleen