Re: [RFC RFC PATCH] mm: convert VM flags from macros to enum

[David Hildenbrand]

On 13.10.25 15:19, Lorenzo Stoakes wrote:
> On Mon, Oct 13, 2025 at 03:07:18PM +0200, Vlastimil Babka wrote:
> > On 10/13/25 14:57, Lorenzo Stoakes wrote:
> > > FOLL_* flags are an anonymous enum, enum fault_flag is not used as a type
> > > anywhere, nor is vm_fault_reason. So those are both kinda weird as to why we
> > > even name the type (they're in effect anonymous).
> > >
> > > But also 'we do X in the kernel' doesn't mean doing X is right :)
> >
> > I think the example to follow could be GFP flags. Nowadays there's an enum
> > below it, and a layer that adds (__force gfp_t), so you could do similar
> > thing with vm_flags_t.
> >
> > However I'm not sure how compatible is that with Lorenzo's plans.
>
> That's defining bit values in an anonymous enum so isn't really comparable.
>
> But what it's doing, ultimately, in broad terms (other than the opaque bitmap
> type I'll be using for VMA flags) is what my changes will do.
>
> And yeah, trying to do duplicate that is not really a good use of time and will
> conflict with my work.
>
> Overall I think this change is generally unnecessary given that I'm about to
> radically alter how VMA flags are implemented, and actually will cause me
> problems.
>
> But as I said before, I'm happy to prioritise the change that specifies the
> flags based on the bit numbers, I actually have it ready more-or-less.

Yeah, let's do that if you expect to have it ready soonish.

--
Cheers

David / dhildenb