Re: [RFC PATCH 1/3] mm: make persistent huge zero folio read-only

[Lance Yang]

On 2026/6/1 21:49, David Hildenbrand (Arm) wrote:
> On 5/27/26 17:55, Dave Hansen wrote:
> > On 5/26/26 20:56, Xueyuan chen wrote:> +#ifdef
> > CONFIG_READONLY_HUGE_ZERO_FOLIO
> > > +bool __init arch_make_huge_zero_folio_readonly(struct folio *folio);
> > > +#endif
> >
> > All of the #ifdeffery needs to die, IMNHO.
> >
> > This function is also a bad idea. There is nothing "huge zero" specific
> > about it. It takes any old folio and tries to make it read only.
> >
> > Just make it:
> >
> > 	bool __init arch_make_folio_readonly(struct folio *folio)
>
> I'm not sure whether we want a folio-based interface, though.
>
> This will likely be the only folio (that will actually have a "struct folio" in
> the future) compound page we'll ever mark read-only ... whereby I'd guess we'd
> want other non-folio pages to be read-only in the future (encryption keys etc,
> maybe?).
>
> So I'd instead use a page-range based interface or sth like that.

Just to check, did you mean something like:

bool arch_make_pages_readonly(struct page *page, int nr_pages);

?

So it can work on pages as well, not only folios :)