[10] RFR (M/L): 8137099: G1 needs to "upgrade" GC within the safepoint if it can't allocate during that safepoint to avoid OoME

[Thomas Schatzl]

Hi all,

  Erik Duveblad had some offline comments:

New webrevs:
http://cr.openjdk.java.net/~tschatzl/8137099/webrev.2_to_3/ (diff)
http://cr.openjdk.java.net/~tschatzl/8137099/webrev.3/ (full)

- inverting some conditions in the clauses to read better

- extract out the condition to do the maximally compacting full gc
added in this change into a separate method.

Erik Duveblad also noted that this change contains some slight
behavioral change in when a collection is started. I.e. previously TLAB
allocation by itself could not cause a GC. Since this change is already
quite big, he suggested to fix this in a follow-up, and push them
together.

Thanks,
  Thomas