On 25.06.25 10:53, Oscar Salvador wrote:
On Tue, Jun 17, 2025 at 05:43:41PM +0200, David Hildenbrand wrote:
Let's reduce the code duplication and factor out the non-pte/pmd related
magic into vm_normal_page_pfn().
To keep it simpler, check the pfn against both zero folios. We could
optimize this, but as it's only for the !CONFIG_ARCH_HAS_PTE_SPECIAL
case, it's not a compelling micro-optimization.
With CONFIG_ARCH_HAS_PTE_SPECIAL we don't have to check anything else,
really.
It's a good question if we can even hit the !CONFIG_ARCH_HAS_PTE_SPECIAL
scenario in the PMD case in practice: but doesn't really matter, as
it's now all unified in vm_normal_page_pfn().
While at it, add a check that pmd_special() is really only set where we
would expect it.
No functional change intended.
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Comment below
struct folio *vm_normal_folio(struct vm_area_struct *vma, unsigned long addr,
@@ -650,35 +661,12 @@ struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
{
unsigned long pfn = pmd_pfn(pmd);
- /* Currently it's only used for huge pfnmaps */
Although the check kind of spells it out, we could leave this one and also add
that huge_zero_pfn, to make it more explicit.
I don't think that comment is required anymore -- we do exactly what
vm_normal_page() does + documents,
What the current users are is not particularly important anymore.
Or why do you think it would still be important?
--
Cheers,
David / dhildenb
