protected void setBits(long bitMask) {
    boolean done;
    do {
      long bits = getLastModifiedField();
      long newBits = bits | bitMask;
      if (bits == newBits) {
        return;
      }
      done = compareAndSetLastModifiedField(bits, newBits);
    } while (!done);
  }
Any bits in "bitMask" that are 1 will be set.
geode-core/src/main/java/org/apache/geode/internal/cache/entries/AbstractRegionEntry.java