[15] RFR 8245880: Shenandoah: should not mark all code roots if class unloading is enabled

[Zhengyu Gu]

Sorry, seems that we check class unloading flag in 
concurrent_scan_code_roots(), which is not optimal, I will change 
synopsis and send out new webrev.

Thanks,

-Zhengyu

On 5/27/20 10:56 AM, Zhengyu Gu wrote:
> Currently, concurrent code root scanning marks all code cache, no matter 
> if class unloading is enabled, which is wrong.
> 
> When class unloading is enabled, only on-stack code roots should be marked.
> 
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8245880
> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8245880/webrev.00/
> 
> Test:
>    hotspot_gc_shenandoah
>    tier1 with Shenandoah
> 
> 
> Thanks,
> 
> -Zhengyu