RFR (S) 8160539: Stack frame scanning acquires several mutexes

[Kim Barrett]

> On Mar 25, 2019, at 8:34 PM, David Holmes <david.holmes at oracle.com> wrote:
> 
> Hi Coleen,
> 
> On 26/03/2019 3:49 am, coleen.phillimore at oracle.com wrote:
>> Summary: Use CAS instead of OopMapCacheAlloc_lock
>> Tested with hs-tier1-5 and specjbb2017.
>> open webrev at http://cr.openjdk.java.net/~coleenp/2019/8160539.01/webrev
>> bug link https://bugs.openjdk.java.net/browse/JDK-8160539
> 
> How expensive is it to create OopMapCache? Are we likely to encounter a lot of contention on this?

I had the same question.  I suspect the added cognitive load of lock-free code
(vs the existing DCLP) is not worthwhile here.