8027295: Free CSet takes ~50% of young pause time Summary: Improve fast card cache iteration and avoid taking locks when freeing the collection set. Reviewed-by: brutisso

8035815: Cache-align and pad the from card cache Summary: The from card cache is a very frequently accessed data structure. It is essentially a 2d array of per-region values, one row of values for every GC thread. Pad and align the data structure to avoid false sharing. Reviewed-by: stefank

8035406: Improve data structure for Code Cache remembered sets Summary: Change the code cache remembered sets data structure from a GrowableArray to a chunked list of nmethods. This makes the data structure more amenable to parallelization, and decreases freeing time. Reviewed-by: mgerdin, brutisso