Re: [PATCH v2 01/15] mm/vma: introduce VMA virtual page offset field and add helpers
From: Lorenzo Stoakes (ARM)
Date: Mon Jul 27 2026 - 08:06:02 EST
On Mon, Jul 20, 2026 at 01:26:09PM -0400, Gregory Price wrote:
> On Mon, Jul 20, 2026 at 05:56:52PM +0100, Lorenzo Stoakes (ARM) wrote:
> > On Mon, Jul 20, 2026 at 11:49:00AM -0400, Gregory Price wrote:
> > > On Mon, Jul 20, 2026 at 03:38:27PM +0100, Lorenzo Stoakes (ARM) wrote:
> > > >
> > > > The virtual page offset of a VMA is equal to vma->vm_start >> PAGE_SHIFT if
> > > > they are unfaulted or were not remapped, otherwise it is equal to this
> > > > value at the point of first fault.
> > > >
> > >
> > > The latter half of this description is a bit confusing.
> > >
> > > Why would the value differ from (vma->vm_start >> PAGE_SHIFT)?
> > > (because it's file backed?
> >
> > Because the VMA gets remapped.
> >
> > If it's remapped when it's unfaulted, then virtual page offset gets updated, if
> > it's faulted then not.
> >
>
> ahhhhh the wording is just wonky then
>
> when faulted or remapped, x is...
> when unfaulted or unremapped, x is...
>
> instead of
>
> x is ... if unfaulted or were not remapped, otherwise...
>
> Sort of a complex combination of 3 negatives there.
>
> ~Gregory
>
Ack, will improve wording!
Cheers, Lorenzo