6728271: G1: Cleanup G1CollectedHeap::get_gc_alloc_regions()
It allows the last half-full region to be allocated to during a GC to be reused during the next GC.
Reviewed-by: apetrusenko, jcoomes
The length of the fast cset test vector is decided at the beginning of a GC, but more regions can be added during the GC. The simple fix is to set the length of the fast cset test vector to the max.
Reviewed-by: iveresov
6720334: G1: don't update RSets of collection set regions during an evacuation pause
Introduced a deferred update mechanism for delaying the rset updates during the collection pause
Reviewed-by: apetrusenko, tonyp
Under certain circumstances (evacuation failure) the pause time is not communicated to the policy and, as a result, the pause time field is not initialized properly.
Reviewed-by: jmasa
For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not.
Reviewed-by: jmasa
Fixed the incorrect assigment to G1OffsetTableContigSpace::_gc_time_stamp. Also added a little more paranoia to operations on a global timestamp.
Reviewed-by: tonyp
Do not coalesce dead and moved objects when removing self-forwarding pointers during the evacuation failure. Also fixed a issue in a BOT refinement code for TLABs.
Reviewed-by: tonyp, jcoomes
