1 files changed, 14 insertions, 0 deletions

diff --git a/mm/madvise.c b/mm/madvise.c
index 66c31264f062..d9ae2067952e 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -11,6 +11,7 @@
 #include <linux/mempolicy.h>
 #include <linux/hugetlb.h>
 #include <linux/sched.h>
+#include <linux/ksm.h>
 
 /*
  * Any behaviour which results in changes to the vma->vm_flags needs to
@@ -63,6 +64,12 @@ static long madvise_behavior(struct vm_area_struct * vma,
                 }
                 new_flags &= ~VM_DONTCOPY;
                 break;
+        case MADV_MERGEABLE:
+        case MADV_UNMERGEABLE:
+                error = ksm_madvise(vma, start, end, behavior, &new_flags);
+                if (error)
+                        goto out;
+                break;
         }
 
         if (new_flags == vma->vm_flags) {
@@ -239,6 +246,10 @@ madvise_behavior_valid(int behavior)
         case MADV_REMOVE:
         case MADV_WILLNEED:
         case MADV_DONTNEED:
+#ifdef CONFIG_KSM
+        case MADV_MERGEABLE:
+        case MADV_UNMERGEABLE:
+#endif
                 return 1;
 
         default:
@@ -273,6 +284,9 @@ madvise_behavior_valid(int behavior)
  *  MADV_DONTFORK - omit this area from child's address space when forking:
  *              typically, to avoid COWing pages pinned by get_user_pages().
  *  MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
+ *  MADV_MERGEABLE - the application recommends that KSM try to merge pages in
+ *              this area with pages of identical content from other such areas.
+ *  MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others.
  *
  * return values:
  *  zero    - success