RFR(M): 8190430 [MVT] Fixing GC support for Thread-local value buffers

[Frederic Parain]

Here’s an updated webrev with unnecessary GC barriers removed,
and an assertion added to check the consistency of the mark bits
of buffered values.

http://cr.openjdk.java.net/~fparain/8190430/webrev.02/index.html

Fred


> On Nov 8, 2017, at 14:39, Frederic Parain <frederic.parain at oracle.com> wrote:
> 
> Updated webrev where the memory allocation for the TLVB is changed from
> on-demand mmap() calls to a reserve/lazy commits mechanism.
> 
> http://cr.openjdk.java.net/~fparain/8190430/webrev.01/
> 
> Fred
> 
> 
>> On Oct 31, 2017, at 13:21, Frederic Parain <frederic.parain at oracle.com> wrote:
>> 
>> Please review this changeset fixing the GC support and other
>> issues with the Thread-Local Value Buffer:
>> 
>> http://cr.openjdk.java.net/~fparain/8190430/webrev.00/
>> 
>> This changeset re-activates the TLVB by default.
>> The VTBuffer test has been fixed to generate value types
>> with object references.
>> 
>> All hotspot_valhalla tests pass.
>> 
>> Thank you,
>> 
>> Fred
>