SWP_HWPOISON_NUM   57 include/linux/swap.h #define SWP_MIGRATION_READ	(MAX_SWAPFILES + SWP_HWPOISON_NUM)
SWP_HWPOISON_NUM   58 include/linux/swap.h #define SWP_MIGRATION_WRITE	(MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
SWP_HWPOISON_NUM   74 include/linux/swap.h 	((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)