private static long alignUp(final long x) {
    return (x + (BITS_PER_WORD - 1)) & -BITS_PER_WORD;
  }
Returns upper boundary (aligned to multiple of BITS_PER_WORD) of bitmap range x belongs to.
hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/store/wal/BitSetNode.java