SWP_TB_COUNT_BITS
BUILD_BUG_ON(SWP_TB_COUNT_BITS < SWAP_COUNT_MIN_BITS);
#define SWP_TB_COUNT_MASK (~((~0UL) >> SWP_TB_COUNT_BITS))
#define SWP_TB_COUNT_SHIFT (BITS_PER_LONG - SWP_TB_COUNT_BITS)
#define SWP_TB_COUNT_MAX ((1 << SWP_TB_COUNT_BITS) - 1)