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

[Matthew Wilcox]

On Fri, Feb 06, 2026 at 07:09:56PM +0100, David Hildenbrand (Arm) wrote:
> 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 :)

OK, you're the KSM maintainer.  There doesn't seem to be anywhere else
in the KSM code which handles large folios, so this is just removing
code that was recently added?