cover_size
cover_size = 1 << cover_shift, //----cover_size
cover_size = 1 << cover_shift,
cover_size = 1 << cover_shift,
cover_size = 1 << cover_shift,
cover_size = 1 << cover_shift,
cover_size = 1 << cover_shift,
cover_size = 1 << cover_shift,