RFR: 8232365: Implementation for JEP 363: Remove the Concurrent Mark Sweep (CMS) Garbage Collector

[Leo Korinth]

On 29/10/2019 10:50, Magnus Ihse Bursie wrote:
> On 2019-10-24 20:03, Leo Korinth wrote:
>> Fixes after suggestions from Coleen, David, Erik, Igor and Kim:
>>
>> http://cr.openjdk.java.net/~lkorinth/8232365/00_01/ (incremental)
>> http://cr.openjdk.java.net/~lkorinth/8232365/01/ (full)
> Build changes now look fine.
> 
> /Magnus

Thanks Magnus, I will add you as a reviewer.

/Leo
>>
>> Thanks,
>> Leo
>>
>> On 18/10/2019 10:20, Leo Korinth wrote:
>>> Hi,
>>>
>>> Here is a patch that removes the CMS GC.
>>>
>>> I have neither tested arm nor ppc; I hope my changes to those .ad 
>>> files are correct, if someone can test those architectures, that 
>>> would be great.
>>>
>>> Please take an extra look at 
>>> CollectedHeap::check_for_non_bad_heap_word_value, it was buggy before 
>>> (but never called), It is now called (and hopefully correct).
>>>
>>> I have tried to remove most parts of CMS. I have not made it a goal 
>>> to remove all traces of CMS. I guess there are much more to cleanup, 
>>> and suggestions of more to remove are welcomed. I think more 
>>> complicated cleanups should be dealt with in separate enhancements.
>>>
>>> Not fully addressed in code, but an issue that has to be dealt with, 
>>> how do I obsolete -Xconcgc and -Xnoconcgc? I believe the option 
>>> should be obsoleted, though I do not know if we have any precedence 
>>> obsoleting -X options.
>>>
>>> My patch prints:
>>>
>>> $ java -Xconcgc -jar Notepad.jar
>>> Java HotSpot(TM) 64-Bit Server VM warning: -Xconcgc uses 
>>> UseConcMarkSweepGC
>>>
>>> I guess that is not enough for being obsolete, compare with:
>>>
>>> $ java -XX:UseConcMarkSweepGC -jar Notepad.jar
>>> Java HotSpot(TM) 64-Bit Server VM warning: Ignoring option 
>>> UseConcMarkSweepGC; support was removed in 14.0
>>>
>>> Bug:
>>>    https://bugs.openjdk.java.net/browse/JDK-8232365
>>>
>>> Webrev:
>>>    http://cr.openjdk.java.net/~lkorinth/8232365/00
>>>
>>> Testing:
>>>    tier 1-5.
>>>
>>> Thanks,
>>> Leo
>