Strange behaviour on half-occupied heap

[Simon Ogorodnik]

> On 29 Aug 2018, at 18:49, Aleksey Shipilev <shade at redhat.com> wrote:
> 
> On 08/29/2018 05:36 PM, Simon Ogorodnik wrote:
>> Even with -XX:ShenandoahMaxCSetFactor=60 same situation reproduces. 
>> 
>> I recorded visualiser:
>> https://drive.google.com/file/d/1uhJiGE3kCCDZNbOds6G853u7AmSlPbs0/view?usp=sharing
> 
> Aha. Heuristics have run is into the corner: there is no space to evacuate to with concurrent GC,
> and all we are left to do is Full GC. I think I know what to do -- we have the "evacuation reserve"
> patch that we need to get in, so heap always have some reserved space to evacuate to.
> 
> Give it more heap to work around meanwhile.


I doubled heap to 4G, but situation still reproduces after a bit more time

Maybe there also some problem with marking
Why those garbage is marked with ‘Live’ color in visualiser and not getting into CSet? 
Is it actually live and HPROF heap dump is incorrect?