RFR: Soft refs should be purged reliably on allocation failure, or with compact heuristics

[Roman Kennke]

Am 03.09.2018 um 19:31 schrieb Aleksey Shipilev:
> http://cr.openjdk.java.net/~shade/shenandoah/softrefs-trigger/webrev.01/
> 
> Have been following up on the question from Simon: why Full GC cleans up several times more heap
> than degenerated or normal cycle? My gut feeling was about soft-references, and experiments
> confirmed it. But, this led me to discover our soft ref policy needs reliability fixes. This patch
> does them: we purge soft refs on allocation failure, and some heuristics (compact) do that
> unconditionally.
> 
> Testing: IDEA with sh/jdk8 and this patch beckported, tier3_gc_shenandoah (running)
> 
> Thanks,
> -Aleksey
> 

Good. Thanks!
Roman