RFR: Verifier performance improvements: scan objects once, avoid double oop checks

[Zhengyu Gu]

Okay.

-Zhengyu



On 06/27/2017 12:14 PM, Aleksey Shipilev wrote:
> Marked object verification now takes considerable time, because it now touches
> normally unreachable objects after TAMS. This captures most recent allocations,
> especially during Init Mark verification, when immediate garbage regions are not
> yet reclaimed.
>
> We can improve verifier performance a little bit by using verification bitmap to
> avoid scanning already scanned objects. We can also revise fully inline is_oop
> assert to avoid useless double checking for is_in and check_alignment.
>
> Webrev:
>   http://cr.openjdk.java.net/~shade/shenandoah/verifier-perf/webrev.01/
>
> Thanks,
> -Aleksey
>