linux-next
### hits:
/arch/x86/include/asm/pgtable-3level.h:128:20: error: redefinition of ‘native_pud_clear’ ./arch/x86/include/asm/pgtable-3level.h:124:20: note: previous definition of ‘native_pud_clear’ was here
这里：
http://lkml.iu.edu/hypermail/linux/kernel/1602.0/03087.html
on x86_64:
when CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD is enabled and CONFIG_TRANSPARENT_HUGEPAGE is not enabled:
../fs/proc/task_mmu.c: In function ‘smaps_pud_range’: ../fs/proc/task_mmu.c:596:2: error: implicit declaration of function ‘is_huge_zero_pud’ [-Werror=implicit-function-declaration] if (is_huge_zero_pud(*pud))