RFR(XS) 8224115: Shenandoah: Eliminate RWLock that protects recorded nmethod data array

[Zhengyu Gu]

Split the original patch, moved root processing changes that deal with 
traversal GC problem into JDK-8224179.

Updated webrev: http://cr.openjdk.java.net/~zgu/JDK-8224115/webrev.01/

Test:
   reran hotspot_gc_shenandoah (fastdebug and release)
   applications/ctw/modules (fastdebug)

Thanks,

-Zhengyu


On 5/17/19 11:57 AM, Zhengyu Gu wrote:
> I would like to eliminate RWLock that used to protect recorded nmethod 
> data array in ShenandoahCodeRoots, because the methods that update the 
> array, are already guarded by CodeCache_lock.
> 
> The patch also helps concurrent class unloading work, by avoiding two 
> lock dances, which are deadlock prone.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8224115
> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8224115/webrev.00/
> 
> Test:
>    hotspot_gc_shenandoah (fastdebug and release)
> 
> Thanks,
> 
> -Zhengyu