RFR (8u-backport): Implement early update references phase

[Aleksey Shipilev]

On 05/09/2017 09:02 PM, Roman Kennke wrote:
> Am 09.05.2017 um 19:24 schrieb Aleksey Shipilev:
>> On 05/09/2017 07:14 PM, Roman Kennke wrote:
>>> This is a straight backport of the early update references phase and all
>>> related code from JDK9.
>>>
>>> http://cr.openjdk.java.net/~rkennke/backport-uprefs/webrev.00/
>>> <http://cr.openjdk.java.net/%7Erkennke/backport-uprefs/webrev.00/>
>>>
>>> Testing: hotspot_gc_shenandoah, specjvm compiler
>>>
>>> Ok?
>> Nice and tidy, thanks.
>>
>> Comparing with 9, these are the interesting differences, which might be good to
>> fix in this iteration:
>>
>>  *) ShenandoahHeuristics::record_gc_start/end() seem to be missing?
> This one seems to be used only for partial GC. However, it looks more
> consistent in this iteration. Added.
> 
>>  *) ShenandoahHeap::update_refs_in_progress_addr() seems to be missing?
> Similar: this is only used for the improved store checks, but looks more
> consistent here. Added too.
> 
> I also added heap occupancy logging for the update refs pause, as
> present in jdk9.
> 
> http://cr.openjdk.java.net/~rkennke/backport-uprefs/webrev.01/
> <http://cr.openjdk.java.net/%7Erkennke/backport-uprefs/webrev.01/>
> 
> Ok?

OK!

Thanks,
-Aleksey