RFR(XS): 8039089 - List verification enabled in product builds

[Thomas Schatzl]

Hi Jesper,

On Wed, 2014-04-02 at 18:45 +0200, Jesper Wilhelmsson wrote:
> Hi,
> 
> This is a one-liner to stop ConcurrentMark::completeCleanup() from running list 
> verification in product builds.
> 
> It is currently calling _cleanup_list.verify_list(). This will unconditionally 
> run the verification, even in product builds. I replaced it with 
> verify_optional() that only runs the verification code in debug builds.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8039089
> 
> Webrev: http://cr.openjdk.java.net/~jwilhelm/8039089/webrev/


  looks good.

Some request though, as it is somewhat related: HeapRegionSetBase::add()
and HeapRegionSetBase::remove() should assert on that the prev-pointers
of the doubly linked list should be NULL, not only the next pointer.

However the change is fine as is to me.

Thomas