PTRS_PER_PGD       27 arch/x86/include/asm/pgtable-2level_types.h #define PTRS_PER_PGD	1024
PTRS_PER_PGD       33 arch/x86/include/asm/pgtable-3level_types.h #define PTRS_PER_PGD	4
PTRS_PER_PGD       29 arch/x86/include/asm/pgtable_64_types.h #define PTRS_PER_PGD	512