RADIX_PGD_INDEX_SIZE   11 arch/powerpc/include/asm/book3s/64/radix-4k.h #define RADIX_PGD_INDEX_SIZE  13  // size: 8B << 13 = 64KB, maps 2^13 x 512GB =   4PB
RADIX_PGD_INDEX_SIZE   11 arch/powerpc/include/asm/book3s/64/radix-64k.h #define RADIX_PGD_INDEX_SIZE  13  // size: 8B << 13 = 64KB, maps 2^13 x 512GB =   4PB