RFR: Cease JDK 10 support for Shenandoah

[Aleksey Shipilev]

Seems only a few people need it. I would like to go forward with ceasing support.

This is the last call for comments about the need to keep Shenandoah JDK 10 backport supported.

-Aleksey

On 09/19/2018 10:35 AM, Aleksey Shipilev wrote:
> Gauging public interest here as well:
>   https://twitter.com/shipilev/status/1042330798798585856
> 
> -Aleksey
> 
> On 09/19/2018 10:27 AM, Aleksey Shipilev wrote:
>> Upstream had ceased to publish any fixes to 10u, and 11 is going to be released next week. sh/jdk11
>> is stable enough for adopters to use. In fact, many adopters who prefer the up-to-date JDKs already
>> do use sh/jdk11. We also have quite substantial cleanup/backports coming, especially in compiler
>> area. All of the above makes sh/jdk10 support dubious, and I propose we cease it.
>>
>> Like with sh/jdk9 before, let us print the warning message on startup:
>>
>> diff -r 82f1eec5affa src/hotspot/share/gc/shenandoah/shenandoahArguments.cpp
>> --- a/src/hotspot/share/gc/shenandoah/shenandoahArguments.cpp   Mon Sep 10 17:56:38 2018 +0200
>> +++ b/src/hotspot/share/gc/shenandoah/shenandoahArguments.cpp   Wed Sep 19 10:22:47 2018 +0200
>> @@ -29,10 +29,16 @@
>>  #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
>>  #include "gc/shenandoah/shenandoahHeap.hpp"
>>  #include "utilities/defaultStream.hpp"
>>
>>  void ShenandoahArguments::initialize_flags() {
>> +  log_warning(gc)("**************************************************************************");
>> +  log_warning(gc)("*  Shenandoah GC support for this JDK release had ceased.                *");
>> +  log_warning(gc)("*  JDK 10 is a short-term release, and it had reached end of life.       *");
>> +  log_warning(gc)("*  This JDK would not get security, functionality or performance fixes.  *");
>> +  log_warning(gc)("*  Use this build at your own risk, and consider migrating to next JDK.  *");
>> +  log_warning(gc)("**************************************************************************");
>>
>>  #if !(defined AARCH64 || defined AMD64 || defined IA32)
>>    vm_exit_during_initialization("Shenandoah GC is not supported on this platform.");
>>  #endif
>>
>> Testing: tier1_gc_shenandoah
>>
>> Thanks,
>> -Aleksey
>>
> 
>