2 files changed, 20 insertions, 5 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index fce667c0281d..004c9c2aac78 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1389,7 +1389,8 @@ out:
         return ret;
 }
 
-int hugepage_madvise(unsigned long *vm_flags, int advice)
+int hugepage_madvise(struct vm_area_struct *vma,
+                     unsigned long *vm_flags, int advice)
 {
         switch (advice) {
         case MADV_HUGEPAGE:
@@ -1404,6 +1405,13 @@ int hugepage_madvise(unsigned long *vm_flags, int advice)
                         return -EINVAL;
                 *vm_flags &= ~VM_NOHUGEPAGE;
                 *vm_flags |= VM_HUGEPAGE;
+                /*
+                 * If the vma become good for khugepaged to scan,
+                 * register it here without waiting a page fault that
+                 * may not happen any time soon.
+                 */
+                if (unlikely(khugepaged_enter_vma_merge(vma)))
+                        return -ENOMEM;
                 break;
         case MADV_NOHUGEPAGE:
                 /*
@@ -1417,6 +1425,11 @@ int hugepage_madvise(unsigned long *vm_flags, int advice)
                         return -EINVAL;
                 *vm_flags &= ~VM_HUGEPAGE;
                 *vm_flags |= VM_NOHUGEPAGE;
+                /*
+                 * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning
+                 * this vma even if we leave the mm registered in khugepaged if
+                 * it got registered before VM_NOHUGEPAGE was set.
+                 */
                 break;
         }
 
@@ -1784,7 +1797,8 @@ static void collapse_huge_page(struct mm_struct *mm,
         if (address < hstart || address + HPAGE_PMD_SIZE > hend)
                 goto out;
 
-        if (!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always())
+        if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
+            (vma->vm_flags & VM_NOHUGEPAGE))
                 goto out;
 
         /* VM_PFNMAP vmas may have vm_ops null but vm_file set */
@@ -2007,8 +2021,9 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
                         break;
                 }
 
-                if (!(vma->vm_flags & VM_HUGEPAGE) &&
-                    !khugepaged_always()) {
+                if ((!(vma->vm_flags & VM_HUGEPAGE) &&
+                     !khugepaged_always()) ||
+                    (vma->vm_flags & VM_NOHUGEPAGE)) {
                         progress++;
                         continue;
                 }
diff --git a/mm/madvise.c b/mm/madvise.c
index bbac126e03ed..2221491ed503 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -73,7 +73,7 @@ static long madvise_behavior(struct vm_area_struct * vma,
                 break;
         case MADV_HUGEPAGE:
         case MADV_NOHUGEPAGE:
-                error = hugepage_madvise(&new_flags, behavior);
+                error = hugepage_madvise(vma, &new_flags, behavior);
                 if (error)
                         goto out;
                 break;