MAXMEM             53 arch/x86/include/asm/pgtable_32_types.h #define MAXMEM	(VMALLOC_END - PAGE_OFFSET - __VMALLOC_RESERVE)
MAXMEM             57 arch/x86/include/asm/pgtable_64_types.h #define MAXMEM		 _AC(__AC(1, UL) << MAX_PHYSMEM_BITS, UL)