1 files changed, 9 insertions, 5 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 2366578015ad..30feedabc932 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4181,11 +4181,6 @@ fallback:
 	return __alloc_swap_folio(vmf);
 }
 #else /* !CONFIG_TRANSPARENT_HUGEPAGE */
-static inline bool can_swapin_thp(struct vm_fault *vmf, pte_t *ptep, int nr_pages)
-{
-	return false;
-}
-
 static struct folio *alloc_swap_folio(struct vm_fault *vmf)
 {
 	return __alloc_swap_folio(vmf);
@@ -4925,6 +4920,15 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
 	pmd_t entry;
 	vm_fault_t ret = VM_FAULT_FALLBACK;
 
+	/*
+	 * It is too late to allocate a small folio, we already have a large
+	 * folio in the pagecache: especially s390 KVM cannot tolerate any
+	 * PMD mappings, but PTE-mapped THP are fine. So let's simply refuse any
+	 * PMD mappings if THPs are disabled.
+	 */
+	if (thp_disabled_by_hw() || vma_thp_disabled(vma, vma->vm_flags))
+		return ret;
+
 	if (!thp_vma_suitable_order(vma, haddr, PMD_ORDER))
 		return ret;