1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index c0c2bce6b0b7..d9d7e7e56352 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -37,6 +37,16 @@ struct anon_vma {
         atomic_t refcount;
 
         /*
+         * Count of child anon_vmas and VMAs which points to this anon_vma.
+         *
+         * This counter is used for making decision about reusing anon_vma
+         * instead of forking new one. See comments in function anon_vma_clone.
+         */
+        unsigned degree;
+
+        struct anon_vma *parent;        /* Parent of this anon_vma */
+
+        /*
          * NOTE: the LSB of the rb_root.rb_node is set by
          * mm_take_all_locks() _after_ taking the above lock. So the
          * rb_root must only be read/written after taking the above lock