RFR: Rewire control loop to avoid double cleanup work

[Roman Kennke]

Am 19.03.2018 um 11:44 schrieb Aleksey Shipilev:
> http://cr.openjdk.java.net/~shade/shenandoah/concthread-dbl-cleanup/webrev.01/
> 
> Current shortcut cycle does the cleanup twice:
> 
> [14.085s][info][gc] GC(2) Pause Init Mark 0.485ms
> [14.097s][info][gc] GC(2) Concurrent marking 716M->717M(1024M) 11.723ms
> [14.098s][info][gc] GC(2) Pause Final Mark 0.887ms
> [14.168s][info][gc] GC(2) Concurrent cleanup 717M->27M(1024M) 69.883ms  <--- (1)
> [14.170s][info][gc] GC(2) Concurrent cleanup 27M->27M(1024M) 1.782ms    <--- (2)
> 
> We can avoid this by restructuring the code to be more logical.
> 
> Testing: hotspot_gc_shenandoah
> 
> Thanks,
> -Aleksey
> 

Looks good. Thanks!

Roman