RFR: Optimize heap verification

[Roman Kennke]

Am 02.06.2017 um 11:03 schrieb Aleksey Shipilev:
> Hi,
>
> There are few easy things to improve in verification performance- and sanity-wise:
>
>  *) Use non-synchronized Stack instead of SCM Queue. This helps performance, and
> detaches verifier from relying on optimized Shenandoah implementation.
>
>  *) Use single-oop task holder. This again helps performance, and keeps us away
> from Shenandoah-optimized implementation, which deals with workstealing arrays
> better. This does not apply to single-threaded verification.
>
>  *) Peel verification method with test, to aid its inlineablity.
>
>  *) Use BrooksPointer::get_raw to avoid excess asserts inside ::forwardee, which
> we will assert in verification anyway.
>
> All done here:
>  http://cr.openjdk.java.net/~shade/shenandoah/verifier-optimize/webrev.01/
>
> Testing: hotspot_gc_shenandoah
>
> -Aleksey
>
Great! Yes!

Roman