PM_PFRAME_MASK
return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags };
#define PM_PFRAME(x) ((x) & PM_PFRAME_MASK)
#define PM_SWAP_OFFSET(x) (((x) & PM_PFRAME_MASK) >> MAX_SWAPFILES_SHIFT)
return pagemap & ~PM_PFRAME_MASK;