Re: ksm: initialize rmap values directly and make them const

[David Hildenbrand (Arm)]

On 2/6/26 18:34, David Hildenbrand (Arm) wrote:
> On 2/6/26 16:29, Matthew Wilcox wrote:
> > On Fri, Feb 06, 2026 at 03:22:54PM +0800, xu.xin16@xxxxxxxxxx wrote:
> > > make them const to make code more robust. Besides, since KSM folios 
> > > are always
> > > order-0, so folio_nr_pages(KSM folio) is always 1, so the line:
> > >
> > >     "pgoff_end = pgoff_start + folio_nr_pages(folio) - 1;"
> > >
> > > becomes directly:
> > >
> > >     "pgoff_end = pgoff_start;"
> >
> > How do you know KSM folios will always be order 0?  I don't.  NAK this
> > change.
>
> Once that changes we can revisit. ACK from me stands.

And just to elaborate a bit: I don't see support for > 0 happening any 
time soon, and it will require significant changes that I am not even 
sure we would want to maintain upstream :)

--
Cheers,

David