VM_PFNMAP
vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
(VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP)) !=
(VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP));