can't understand why there are additional young GCS during the concurrent marking phase.
the doc said:
While concurrent marking is running, other young-only pauses may occur, until the Remark pause (the first large orange circle), where G1 completes marking. Additional young-only garbage collections may occur until the Cleanup pause.
if a young-gc occur while region A is in concurrent marking phase, what would happen to region A ? would it be evacuated? if so, how dose gc threads process the next & prev bitmap and other data structures (RSet blablabla...) in region A ?
