// will result in random eviction behavior.
    int segmentShift = 0;
    int segmentCount = 1;
    while (segmentCount < concurrencyLevel
        && (!evictsBySize() || segmentCount * 20L <= maxWeight)) {
      ++segmentShift;
      segmentCount <<= 1;
    }
    this.segmentShift = 32 - segmentShift;
    segmentMask = segmentCount - 1;

    this.segments = newSegmentArray(segmentCount);