Re: [PATCH 2/4] mm: perform VMA allocation, freeing, duplication in mm

[Lorenzo Stoakes]

On Thu, Apr 24, 2025 at 11:22:26PM +0200, David Hildenbrand wrote:
> On 24.04.25 23:15, Lorenzo Stoakes wrote:
> > Right now these are performed in kernel/fork.c which is odd and a violation
> > of separation of concerns, as well as preventing us from integrating this
> > and related logic into userland VMA testing going forward, and perhaps more
> > importantly - enabling us to, in a subsequent commit, make VMA
> > allocation/freeing a purely internal mm operation.
> >
> > There is a fly in the ointment - nommu - mmap.c is not compiled if
> > CONFIG_MMU is not set, and there is no sensible place to put these outside
> > of that, so we are put in the position of having to duplication some logic
> > here.
> >
> > This isn't ideal, but since nommu is a niche use-case, already duplicates a
> > great deal of mmu logic by its nature and we can eliminate code that is not
> > applicable to nommu, it seems a worthwhile trade-off.
> >
> > The intent is to move all this logic to vma.c in a subsequent commit,
> > rendering VMA allocation, freeing and duplication mm-internal-only and
> > userland testable.
>
> I'm pretty sure you tried it, but what's the big blocker to have patch #3
> first, so we can avoid the temporary move of the code to mmap.c ?

You know, I didn't :P it was late etc. ;)

But you're right, will rejig accordingly!

>
> --
> Cheers,
>
> David / dhildenb
>