RFR: Account trashed regions from coalesced CM-with-UR

[Roman Kennke]

Am 04.12.2017 um 11:32 schrieb Aleksey Shipilev:
> http://cr.openjdk.java.net/~shade/shenandoah/heuristics-coalesced-trash/webrev.01/
> 
> Adaptive CSet selection runs into trouble with coalesced CM-with-UR: final mark would trash the cset
> regions from the previous cycle, but that would not get accounted for current CSet sizing. In
> extreme cases, it would just make empty CSet, relying solely on immediate garbage:
> 
> [10.687s][info][gc     ] GC(9) Pause Init Mark 1.173ms
> [10.919s][info][gc     ] Cancelling concurrent GC: Allocation Failure
> [10.922s][info][gc     ] GC(9) Concurrent marking 1867M->1985M(2048M) 234.823ms
> [10.922s][info][gc,ergo] GC(9) Adjusting free threshold to: 55% (1126M)
> [11.011s][info][gc,ergo] GC(9) Adaptive CSet selection: free target = 1228M, actual free = 0M; min
> cset = 0M, max cset = 0M
> [11.011s][info][gc,ergo] GC(9) Total Garbage: 355M
> [11.011s][info][gc,ergo] GC(9) Immediate Garbage: 0M, 0 regions (0% of total)
> [11.011s][info][gc,ergo] GC(9) Garbage to be collected: 0M (0% of total), 0 regions
> [11.011s][info][gc,ergo] GC(9) Live objects to be evacuated: 0M
> [11.011s][info][gc,ergo] GC(9) Live/garbage ratio in collected regions: 0%
> [11.011s][info][gc,ergo] GC(9) Free: 0M, 0 regions (0% of total)
> [11.011s][info][gc     ] GC(9) Pause Final Mark 88.866ms
> [11.011s][info][gc     ] GC(9) Concurrent cleanup 1985M->1075M(2048M) 0.183ms
> [11.012s][info][gc     ] GC(9) Concurrent cleanup 1075M->1075M(2048M) 0.719ms
> 
> Testing: hotspot_gc_shenandoah
> 
> Thanks,
> -Aleksey
> 

Ok