RFR: 8221648: Remove CollectedHeap::is_in_closed_subset()

[Thomas Schatzl]

Hi,

On Thu, 2019-03-28 at 22:49 +0100, Per Liden wrote:
> I propose that we remove CollectedHeap::is_in_closed_subset() and
> its unused sibling CollectedHeap::is_in_closed_subset_or_null(). We
> can replace all calls to is_in_closed_subset(), most of which is in 
> verification code, with calls to is_in(). For Serial and ZGC, 
> is_in_closed_subset() is already equivalent to is_in(). For G1, 
> is_in_closed_subset() is very close to equivalent to is_in(). For
> CMS, Parallel, Epsilon, and Shenandoah, is_in_closed_subset() is
> equivalent to is_in_reserved(). However, their is_in() is arguably
> not a lot more expensive, at least not to the degree that is
> motivates keeping the is_in_closed_subset() API around. G1 is the
> only GC that calls is_in_closed_subset() outside of verification code
> (in RegisterHumongousWithInCSetFastTestClosure).
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8221648
> Webrev: http://cr.openjdk.java.net/~pliden/8221648/webrev.0
> 
> /Per

  looks good.

Thomas