From: Peter Xu <peterx@redhat.com>

Introduce a config option that will be selected as long as huge leaves are
involved in pgtable (thp or hugetlbfs).  It would be useful to mark any
code with this new config that can process either hugetlb or thp pages in
any level that is higher than pte level.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 mm/Kconfig | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/Kconfig b/mm/Kconfig
index cb9d470f0bf7..9350ba180d52 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -904,6 +904,9 @@ config READ_ONLY_THP_FOR_FS
 
 endif # TRANSPARENT_HUGEPAGE
 
+config PGTABLE_HAS_HUGE_LEAVES
+	def_bool TRANSPARENT_HUGEPAGE || HUGETLB_PAGE
+
 #
 # UP and nommu archs use km based percpu allocator
 #
-- 
2.41.0

On Wed, Jan 03, 2024 at 05:14:11PM +0800, peterx@redhat.com wrote:
> From: Peter Xu <peterx@redhat.com>
> 
> Introduce a config option that will be selected as long as huge leaves are
> involved in pgtable (thp or hugetlbfs).  It would be useful to mark any
> code with this new config that can process either hugetlb or thp pages in
> any level that is higher than pte level.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  mm/Kconfig | 3 +++
>  1 file changed, 3 insertions(+)

So you mean anything that supports page table entires > PAGE_SIZE ?

Makes sense to me, though maybe add a comment in the kconfig?

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

On Mon, Jan 15, 2024 at 01:37:37PM -0400, Jason Gunthorpe wrote:
> On Wed, Jan 03, 2024 at 05:14:11PM +0800, peterx@redhat.com wrote:
> > From: Peter Xu <peterx@redhat.com>
> > 
> > Introduce a config option that will be selected as long as huge leaves are
> > involved in pgtable (thp or hugetlbfs).  It would be useful to mark any
> > code with this new config that can process either hugetlb or thp pages in
> > any level that is higher than pte level.
> > 
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> > ---
> >  mm/Kconfig | 3 +++
> >  1 file changed, 3 insertions(+)
> 
> So you mean anything that supports page table entires > PAGE_SIZE ?

Yes.

> 
> Makes sense to me, though maybe add a comment in the kconfig?

Sure I'll add some.

> 
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Thanks for your reviews and also positive comments in previous versions,
Jason.  I appreciate that.

I'm just pretty occupied with other tasks recently so I don't yet have time
to revisit this series, along with other comments yet.  I'll do so and
reply to the comments / discussions together afterwards.

-- 
Peter Xu