Re: [RFC 02/10] mm/hmm: Remove dead check for HugeTLB and FS DAX

Peter Xu
2024-04-11T13:37:40Z

On Thu, Apr 11, 2024 at 09:25:30AM -0300, Jason Gunthorpe wrote:
> On Thu, Apr 11, 2024 at 10:57:23AM +1000, Alistair Popple wrote:
> > pud_huge() returns true only for a HugeTLB page. pud_devmap() is only
> > used by FS DAX pages. These two things are mutually exclusive so this
> > code is dead code and can be removed.
>
> I'm not sure this is true.. pud_huge() is mostly a misspelling of pud_leaf()..
>
> > - if (pud_huge(pud) && pud_devmap(pud)) {
>
> I suspect this should be written as:
>
> if (pud_leaf(pud) && pud_devmap(pud)) {
>
> In line with Peter's work here:
>
> https://lore.kernel.org/linux-mm/20240321220802.679544-1-peterx@redhat.com/

Just to provide more information for Alistair, this patch already switched
that over to a _leaf():

https://lore.kernel.org/r/20240318200404.448346-12-peterx@redhat.com

That's in mm-unstable now, so should see that in a rebase.

And btw it's great to see that pxx_devmap() can go away.

Thanks,

--
Peter Xu