RFR 8204947: Port ShenandoahTaskTerminator to mainline and make it default

[Zhengyu Gu]

Hi Kim and Roman,

On 11/29/18 5:22 PM, Roman Kennke wrote:
> Hi Kim,
> 
>>>
>>> I believe if you add a flag, you need to file a CSR.
>>
>> Experimental and diagnositc options don't need a CSR.  From the CSR FAQ:
>> https://wiki.openjdk.java.net/display/csr/CSR+FAQs
>>
>> "Interfaces that are experimental or for diagnostic purposes do not
>> need to go through CSR process, but the CSR process may be employed if
>> feedback from the CSR reviewers is desired."
>>
>> That's a relatively recent change (this calendar year).

I wish I saw this before filing CSR, and somehow, I also missed David 
Holmes' comment 
(http://mail.openjdk.java.net/pipermail/jdk8u-dev/2018-November/008214.html), 
Sigh!


> 
> Interesting! Does that mean that, strictly speaking, we don't need a CSR
> for Shenandoah flags? :-)
> 
> (In any event, it would be nice if you or somebody else from hotspot-gc
> could review it:
> https://bugs.openjdk.java.net/browse/JDK-8214349 )
> 
>> I also think what's being proposed here is more of a diagnostic than
>> experimental flag.  I think an experimental flag ought to be opt-in,
>> e.g. off by default but one can choose to take the risk.  A diagnostic
>> flag can be used to opt-out of the "normal" behavior, in this case to
>> revert back to the old behavior.  Of course, we violate that a lot...
> 
> I agree. Diagnostic seems to fit the purpose better.

Thanks for the suggestion, I changed the flag to diagnostic. Please see 
updated webrev: http://cr.openjdk.java.net/~zgu/JDK-8204947/webrev.03/

I also wanted to update CSR 
(https://bugs.openjdk.java.net/browse/JDK-8214458) to reflect this 
change, but I could not add comments, that made me wonder if I can 
update text when it is in "provisional" status? or do I need to move 
back to "draft" to do so?

Anyway, could you please review CSR also?

FYI:
  Webrev02 passed vmTestbase_vm_gc and submit tests.

Thanks,

-Zhengyu





> 
> Roman
> 
>