Re: [PATCH mm-new v3 1/1] mm/khugepaged: abort collapse scan on non-swap entries

[David Hildenbrand]

> static inline int pte_protnone(pte_t pte)
> {
> 	return (pte_flags(pte) & (_PAGE_PROTNONE | _PAGE_PRESENT))
> 		== _PAGE_PROTNONE;
> }
>
> static inline int pte_present(pte_t a)
> {
> 	return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE);
> }
> ```
>
> On x86, pte_present() returns true for a protnone pte. And I'd assume
> other archs behave similarly ...

Applies to all architecture. prot-none entries must be present, 
otherwise we'd have a lot of other issues :)

--
Cheers

David / dhildenb