On Mon, 29 Jan 2024 13:43:39 +0530 "Aneesh Kumar K.V" [off-list ref] wrote:

quoted

        return (pud_val(pud) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE;
}
#endif

#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static inline int pud_devmap(pud_t pud)
{
        return !!(pud_val(pud) & _PAGE_DEVMAP);
}
#else
static inline int pud_devmap(pud_t pud)
{
        return 0;
}
#endif

We might need some more clarity on this regarding x86 platform's pud huge
page implementation.

static vm_fault_t create_huge_pud(struct vm_fault *vmf)
{
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) &&			\
	defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
	struct vm_area_struct *vma = vmf->vma;
	/* No support for anonymous transparent PUD pages yet */
	if (vma_is_anonymous(vma))
		return VM_FAULT_FALLBACK;
	if (vma->vm_ops->huge_fault)
		return vma->vm_ops->huge_fault(vmf, PUD_ORDER);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
	return VM_FAULT_FALLBACK;
}

cryptic reply, unreplied to.

What's the thinking here?  Should we proceed with the patch as-is, or
are changes needed?