PMD_SIZE           11 arch/x86/include/asm/pgtable_32_types.h # define PMD_SIZE	(1UL << PMD_SHIFT)
PMD_SIZE           49 arch/x86/include/asm/pgtable_64_types.h #define PMD_SIZE	(_AC(1, UL) << PMD_SHIFT)
PMD_SIZE           21 include/asm-generic/pgtable-nopmd.h #define PMD_SIZE  	(1UL << PMD_SHIFT)