THREAD_SIZE_ORDER   17 arch/x86/include/asm/boot.h #define MIN_KERNEL_ALIGN_LG2	(PAGE_SHIFT + THREAD_SIZE_ORDER)
THREAD_SIZE_ORDER   21 arch/x86/include/asm/page_32_types.h #define THREAD_SIZE		(PAGE_SIZE << THREAD_SIZE_ORDER)
THREAD_SIZE_ORDER    5 arch/x86/include/asm/page_64_types.h #define THREAD_SIZE  (PAGE_SIZE << THREAD_SIZE_ORDER)