1 files changed, 30 insertions, 0 deletions

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 1ca371a06516..e86a523875eb 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -787,6 +787,30 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
                 tlb_table_flush(tlb);
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+void thp_split_vma(struct vm_area_struct *vma)
+{
+        unsigned long addr;
+        struct page *page;
+
+        for (addr = vma->vm_start; addr < vma->vm_end; addr += PAGE_SIZE) {
+                page = follow_page(vma, addr, FOLL_SPLIT);
+        }
+}
+
+void thp_split_mm(struct mm_struct *mm)
+{
+        struct vm_area_struct *vma = mm->mmap;
+
+        while (vma != NULL) {
+                thp_split_vma(vma);
+                vma->vm_flags &= ~VM_HUGEPAGE;
+                vma->vm_flags |= VM_NOHUGEPAGE;
+                vma = vma->vm_next;
+        }
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
 /*
  * switch on pgstes for its userspace process (for kvm)
  */
@@ -824,6 +848,12 @@ int s390_enable_sie(void)
         if (!mm)
                 return -ENOMEM;
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+        /* split thp mappings and disable thp for future mappings */
+        thp_split_mm(mm);
+        mm->def_flags |= VM_NOHUGEPAGE;
+#endif
+
         /* Now lets check again if something happened */
         task_lock(tsk);
         if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 ||