RFR (round 1), JDK-8214259: Implementation: JEP 189: Shenandoah: A Low-Pause Garbage Collector

[Roman Kennke]

Hi Kim,

>> On Nov 26, 2018, at 4:39 PM, Roman Kennke <rkennke at redhat.com> wrote:
>>  *) shared-gc
>>     - This is mostly boilerplate that is common to any GC
>>     - referenceProcessor.cpp has a little change to make one assert not fail (next to CMS and G1)
>>     - taskqueue.hpp has some small adjustments to enable subclassing
> 
> I've reviewed the shared-gc webrev.  I only found a few trivial nits.
> 
> ------------------------------------------------------------------------------ 
> src/hotspot/share/gc/shared/gcName.hpp
>   42   NA,
>   43   Shenandoah,
> 
> Putting Shenandoah after NA seems odd.
> 
> ------------------------------------------------------------------------------
> src/hotspot/share/gc/shared/gcConfig.cpp
>   63      CMSGC_ONLY(static CMSArguments      cmsArguments;)
> ...
>   69 SHENANDOAHGC_ONLY(static ShenandoahArguments shenandoahArguments;)
> 
> Code alignment should probably be updated.
> 
> Similarly here:
>   73 static const SupportedGC SupportedGCs[] = {
> ...
>   79 SHENANDOAHGC_ONLY_ARG(SupportedGC(UseShenandoahGC,    CollectedHeap::Shenandoah, shenandoahArguments, "shenandoah gc"))
> 
> and here:
>   97 void GCConfig::fail_if_unsupported_gc_is_selected() {
> ...
>  105   NOT_SHENANDOAHGC(FAIL_IF_SELECTED(UseShenandoahGC,  true));
> 
> ------------------------------------------------------------------------------
> src/hotspot/share/gc/shared/collectedHeap.hpp
>   92 //   ShenandoahHeap
> 
> Moving it after ParallelScavengeHeap would give a better order.
> 
> ------------------------------------------------------------------------------
> src/hotspot/share/gc/shared/barrierSetConfig.hpp
>   36   SHENANDOAHGC_ONLY(f(Shenandoah))
> 
> Why is this "Shenandoah" while all the others are "<something>BarrierSet"?
> 

Don't know. I'll change it to be consistent. I have proposed a patch
with all changes to shenandoah-dev:

http://mail.openjdk.java.net/pipermail/shenandoah-dev/2018-November/008420.html

Will post an updated upstreaming webrev soon.

Thanks for reviewing,
 Roman