ptep_clear_flush_young
int ptep_clear_flush_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep);
extern int ptep_clear_flush_young(struct vm_area_struct *vma,
young |= ptep_clear_flush_young(vma, addr, ptep);
int ptep_clear_flush_young(struct vm_area_struct *vma,