Removed trailing spaces
[libcds.git] / cds / container / impl / bronson_avltree_map_rcu.h
index 905c27e50b69d9a833ba62997ec603c27ed1a40d..13347c5b86ea5c484f9148219bc0385f21701a52 100644 (file)
@@ -159,10 +159,10 @@ namespace cds { namespace container {
 
         static node_type * parent( node_type * pNode, atomics::memory_order order = memory_model::memory_order_relaxed )
         {
-            return pNode->m_pParent.load( order );
+            return pNode->parent( order );
         }
 
-        // RCU safe disposer 
+        // RCU safe disposer
         class rcu_disposer
         {
             node_type *     m_pRetiredList;     ///< head of retired node list
@@ -185,13 +185,13 @@ namespace cds { namespace container {
                 pNode->m_pNextRemoved = m_pRetiredList;
                 m_pRetiredList = pNode;
             }
-            
+
             void dispose_value( mapped_type pVal )
             {
                 assert( m_pRetiredValue == nullptr );
                 m_pRetiredValue = pVal;
             }
-            
+
         private:
             struct internal_disposer
             {
@@ -204,7 +204,7 @@ namespace cds { namespace container {
             void clean()
             {
                 assert( !gc::is_locked() );
-                
+
                 // TODO: use RCU::batch_retire
 
                 // Dispose nodes
@@ -261,7 +261,7 @@ namespace cds { namespace container {
                     assert( pNode->m_pValue.load( memory_model::memory_order_relaxed ) == nullptr );
                     CDS_UNUSED( pNode );
                     return pVal;
-                }, 
+                },
                 update_flags::allow_insert
             ) == update_flags::result_inserted;
         }
@@ -286,11 +286,11 @@ namespace cds { namespace container {
         std::pair<bool, bool> update( K const& key, mapped_type pVal, bool bInsert = true )
         {
             int result = do_update( key, key_comparator(),
-                [pVal]( node_type * ) -> mapped_type 
+                [pVal]( node_type * ) -> mapped_type
                 {
                     return pVal;
                 },
-                update_flags::allow_update | (bInsert ? update_flags::allow_insert : 0) 
+                update_flags::allow_update | (bInsert ? update_flags::allow_insert : 0)
             );
             return std::make_pair( result != 0, (result & update_flags::result_inserted) != 0 );
         }
@@ -331,8 +331,8 @@ namespace cds { namespace container {
         bool erase_with( K const& key, Less pred )
         {
             CDS_UNUSED( pred );
-            return do_remove( 
-                key, 
+            return do_remove(
+                key,
                 cds::opt::details::make_comparator_from_less<Less>(),
                 []( key_type const&, mapped_type pVal, rcu_disposer& disp ) -> bool { disp.dispose_value( pVal ); return true;  }
             );
@@ -357,13 +357,13 @@ namespace cds { namespace container {
         template <typename K, typename Func>
         bool erase( K const& key, Func f )
         {
-            return do_remove( 
-                key, 
-                key_comparator(), 
-                [&f]( key_type const& key, mapped_type pVal, rcu_disposer& disp ) -> bool { 
+            return do_remove(
+                key,
+                key_comparator(),
+                [&f]( key_type const& key, mapped_type pVal, rcu_disposer& disp ) -> bool {
                     assert( pVal );
-                    f( key, *pVal ); 
-                    disp.dispose_value(pVal); 
+                    f( key, *pVal );
+                    disp.dispose_value(pVal);
                     return true;
                 }
             );
@@ -380,13 +380,13 @@ namespace cds { namespace container {
         bool erase_with( K const& key, Less pred, Func f )
         {
             CDS_UNUSED( pred );
-            return do_remove( 
-                key, 
+            return do_remove(
+                key,
                 cds::opt::details::make_comparator_from_less<Less>(),
-                [&f]( key_type const& key, mapped_type pVal, rcu_disposer& disp ) -> bool { 
+                [&f]( key_type const& key, mapped_type pVal, rcu_disposer& disp ) -> bool {
                     assert( pVal );
-                    f( key, *pVal ); 
-                    disp.dispose_value(pVal); 
+                    f( key, *pVal );
+                    disp.dispose_value(pVal);
                     return true;
                 }
             );
@@ -584,7 +584,7 @@ namespace cds { namespace container {
         template <typename K, typename Func>
         bool find( K const& key, Func f )
         {
-            return do_find( key, key_comparator(), 
+            return do_find( key, key_comparator(),
                 [&f]( node_type * pNode ) -> bool {
                     assert( pNode != nullptr );
                     mapped_type pVal = pNode->m_pValue.load( memory_model::memory_order_relaxed );
@@ -608,7 +608,7 @@ namespace cds { namespace container {
         bool find_with( K const& key, Less pred, Func f )
         {
             CDS_UNUSED( pred );
-            return do_find( key, cds::opt::details::make_comparator_from_less<Less>(), 
+            return do_find( key, cds::opt::details::make_comparator_from_less<Less>(),
                 [&f]( node_type * pNode ) -> bool {
                     assert( pNode != nullptr );
                     mapped_type pVal = pNode->m_pValue.load( memory_model::memory_order_relaxed );
@@ -617,7 +617,7 @@ namespace cds { namespace container {
                         return true;
                     }
                     return false;
-                } 
+                }
             );
         }
 
@@ -737,7 +737,7 @@ namespace cds { namespace container {
                 void operator()( size_t nLevel, size_t hLeft, size_t hRight );
             };
             \endcode
-            where 
+            where
             - \p nLevel - the level where the violation is found
             - \p hLeft - the height of left subtree
             - \p hRight - the height of right subtree
@@ -797,7 +797,7 @@ namespace cds { namespace container {
             find_result result;
             {
                 rcu_lock l;
-                result = try_find( key, cmp, f, m_pRoot, 1, 0 );
+                result = try_find( key, cmp, f, m_pRoot, right_child, 0 );
             }
             assert( result != find_result::retry );
             return result == find_result::found;
@@ -861,8 +861,9 @@ namespace cds { namespace container {
             {
                 rcu_lock l;
 
-                int result = update_flags::failed;
-                do {
+                while ( true ) {
+                    int result;
+
                     // get right child of root
                     node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
                     if ( pChild ) {
@@ -875,8 +876,15 @@ namespace cds { namespace container {
                         else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire )) {
                             result = try_extract_minmax( nDir, func, m_pRoot, pChild, nChildVersion, removed_list );
                         }
+                        else
+                            result = update_flags::retry;
                     }
-                } while ( result == update_flags::retry );
+                    else
+                        return;
+
+                    if ( result == update_flags::retry )
+                        m_stat.onRemoveRetry();
+                }
             }
         }
 
@@ -932,10 +940,8 @@ namespace cds { namespace container {
             while ( true ) {
                 node_type * pChild = child( pNode, nDir );
                 if ( !pChild ) {
-                    if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
-                        m_stat.onFindRetry();
+                    if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
                         return find_result::retry;
-                    }
 
                     m_stat.onFindFailed();
                     return find_result::not_found;
@@ -963,32 +969,23 @@ namespace cds { namespace container {
                     m_stat.onFindWaitShrinking();
                     pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
 
-                    if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
-                        m_stat.onFindRetry();
+                    if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
                         return find_result::retry;
-                    }
                 }
-                else if ( nChildVersion != node_type::unlinked ) {
-                    if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
-                        m_stat.onFindRetry();
+                else if ( nChildVersion != node_type::unlinked && child( pNode, nDir ) == pChild )
+                {
+                    if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
                         return find_result::retry;
-                    }
 
                     find_result found = try_find( key, cmp, f, pChild, nCmp, nChildVersion );
-                    if ( found != find_result::retry ) {
-                        if ( found == find_result::not_found && child(pNode, nDir) != pChild ) {
-                            // Oops! That is a bug!!!
-                            m_stat.onFindNotFoundRetry();
-                        }
-                        else
-                            return found;
-                    }
+                    if ( found != find_result::retry )
+                        return found;
                 }
 
-                if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
-                    m_stat.onFindRetry();
+                if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
                     return find_result::retry;
-                }
+
+                m_stat.onFindRetry();
             }
         }
 
@@ -997,8 +994,9 @@ namespace cds { namespace container {
         {
             assert( gc::is_locked() );
 
-            int result;
-            do {
+            while ( true ) {
+                int result;
+
                 // get right child of root
                 node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
                 if ( pChild ) {
@@ -1008,12 +1006,11 @@ namespace cds { namespace container {
                         pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
                         result = update_flags::retry;
                     }
-                    else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire )) {
-                        result = try_update( key, cmp, nFlags, funcUpdate, m_pRoot, pChild, nChildVersion, disp );
-                    }
+                    else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire ))
+                        result = try_update( key, cmp, nFlags, funcUpdate, pChild, nChildVersion, disp );
                     else
                         result = update_flags::retry;
-                } 
+                }
                 else {
                     // the tree is empty
                     if ( nFlags & update_flags::allow_insert ) {
@@ -1041,8 +1038,12 @@ namespace cds { namespace container {
 
                     return update_flags::failed;
                 }
-            } while ( result == update_flags::retry );
-            return result;
+
+                if ( result == update_flags::retry )
+                    m_stat.onUpdateRetry();
+                else
+                    return result;
+            }
         }
 
         template <typename K, typename Compare, typename Func>
@@ -1050,8 +1051,9 @@ namespace cds { namespace container {
         {
             assert( gc::is_locked() );
 
-            int result;
-            do {
+            while ( true ) {
+                int result;
+
                 // get right child of root
                 node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
                 if ( pChild ) {
@@ -1069,33 +1071,32 @@ namespace cds { namespace container {
                 }
                 else
                     return false;
-            } while ( result == update_flags::retry );
 
-            return result == update_flags::result_removed;
+                if ( result == update_flags::retry )
+                    m_stat.onRemoveRetry();
+                else
+                    return result == update_flags::result_removed;
+            }
         }
 
         template <typename K, typename Compare, typename Func>
-        int try_update( K const& key, Compare cmp, int nFlags, Func funcUpdate, node_type * pParent, node_type * pNode, version_type nVersion, rcu_disposer& disp )
+        int try_update( K const& key, Compare cmp, int nFlags, Func funcUpdate, node_type * pNode, version_type nVersion, rcu_disposer& disp )
         {
             assert( gc::is_locked() );
             assert( nVersion != node_type::unlinked );
-            CDS_UNUSED( pParent );
 
             int nCmp = cmp( key, pNode->m_key );
             if ( nCmp == 0 ) {
-                if ( nFlags & update_flags::allow_update ) {
-                    return try_update_node( funcUpdate, pNode, disp );
-                }
+                if ( nFlags & update_flags::allow_update )
+                    return try_update_node( funcUpdate, pNode, nVersion, disp );
                 return update_flags::failed;
             }
 
-            int result;
-            do {
+            while ( true ) {
+                int result;
                 node_type * pChild = child( pNode, nCmp );
-                if ( pNode->version(memory_model::memory_order_acquire) != nVersion ) {
-                    m_stat.onUpdateRetry();
+                if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
                     return update_flags::retry;
-                }
 
                 if ( pChild == nullptr ) {
                     // insert new node
@@ -1106,37 +1107,39 @@ namespace cds { namespace container {
                 }
                 else {
                     // update child
-                    result = update_flags::retry;
                     version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
                     if ( nChildVersion & node_type::shrinking ) {
                         m_stat.onUpdateWaitShrinking();
                         pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
                         // retry
+                        result = update_flags::retry;
                     }
                     else if ( pChild == child( pNode, nCmp )) {
                         // this second read is important, because it is protected by nChildVersion
 
                         // validate the read that our caller took to get to node
-                        if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
-                            m_stat.onUpdateRetry();
+                        if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
                             return update_flags::retry;
-                        }
 
                         // At this point we know that the traversal our parent took to get to node is still valid.
                         // The recursive implementation will validate the traversal from node to
                         // child, so just prior to the node nVersion validation both traversals were definitely okay.
                         // This means that we are no longer vulnerable to node shrinks, and we don't need
                         // to validate node version any more.
-                        result = try_update( key, cmp, nFlags, funcUpdate, pNode, pChild, nChildVersion, disp );
+                        result = try_update( key, cmp, nFlags, funcUpdate, pChild, nChildVersion, disp );
                     }
+                    else
+                        result = update_flags::retry;
                 }
 
-                if ( result == update_flags::retry && pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
+                if ( result == update_flags::retry ) {
+                    if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
+                        return update_flags::retry;
                     m_stat.onUpdateRetry();
-                    return update_flags::retry;
                 }
-            } while ( result == update_flags::retry );
-            return result;
+                else
+                    return result;
+            }
         }
 
         template <typename K, typename Compare, typename Func>
@@ -1149,17 +1152,15 @@ namespace cds { namespace container {
             if ( nCmp == 0 )
                 return try_remove_node( pParent, pNode, nVersion, func, disp );
 
-            int result;
-            do {
+            while ( true ) {
+                int result;
+
                 node_type * pChild = child( pNode, nCmp );
-                if ( pNode->version(memory_model::memory_order_acquire) != nVersion ) {
-                    m_stat.onRemoveRetry();
+                if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
                     return update_flags::retry;
-                }
 
-                if ( pChild == nullptr ) {
+                if ( pChild == nullptr )
                     return update_flags::failed;
-                }
                 else {
                     // update child
                     result = update_flags::retry;
@@ -1168,15 +1169,14 @@ namespace cds { namespace container {
                         m_stat.onRemoveWaitShrinking();
                         pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
                         // retry
+                        result = update_flags::retry;
                     }
                     else if ( pChild == child( pNode, nCmp )) {
                         // this second read is important, because it is protected by nChildVersion
 
                         // validate the read that our caller took to get to node
-                        if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
-                            m_stat.onRemoveRetry();
+                        if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
                             return update_flags::retry;
-                        }
 
                         // At this point we know that the traversal our parent took to get to node is still valid.
                         // The recursive implementation will validate the traversal from node to
@@ -1185,14 +1185,18 @@ namespace cds { namespace container {
                         // to validate node version any more.
                         result = try_remove( key, cmp, func, pNode, pChild, nChildVersion, disp );
                     }
+                    else
+                        result = update_flags::retry;
                 }
 
-                if ( result == update_flags::retry && pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
+                if ( result == update_flags::retry ) {
+                    if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
+                        return update_flags::retry;
                     m_stat.onRemoveRetry();
-                    return update_flags::retry;
                 }
-            } while ( result == update_flags::retry );
-            return result;
+                else
+                    return result;
+            }
         }
 
         template <typename Func>
@@ -1201,34 +1205,31 @@ namespace cds { namespace container {
             assert( gc::is_locked() );
             assert( nVersion != node_type::unlinked );
 
-            int result;
-            do {
+            while ( true ) {
+                int result;
                 node_type * pChild = child( pNode, nDir );
-                if ( pNode->version(memory_model::memory_order_acquire) != nVersion ) {
-                    m_stat.onRemoveRetry();
+                if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
                     return update_flags::retry;
-                }
 
                 if ( pChild == nullptr ) {
                     // Found min/max
                     return try_remove_node( pParent, pNode, nVersion, func, disp );
                 }
                 else {
-                    result = update_flags::retry;
+                    //result = update_flags::retry;
                     version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
                     if ( nChildVersion & node_type::shrinking ) {
                         m_stat.onRemoveWaitShrinking();
                         pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
                         // retry
+                        result = update_flags::retry;
                     }
                     else if ( pChild == child( pNode, nDir )) {
                         // this second read is important, because it is protected by nChildVersion
 
                         // validate the read that our caller took to get to node
-                        if ( pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
-                            m_stat.onRemoveRetry();
+                        if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
                             return update_flags::retry;
-                        }
 
                         // At this point we know that the traversal our parent took to get to node is still valid.
                         // The recursive implementation will validate the traversal from node to
@@ -1237,14 +1238,18 @@ namespace cds { namespace container {
                         // to validate node version any more.
                         result = try_extract_minmax( nDir, func, pNode, pChild, nChildVersion, disp );
                     }
+                    else
+                        result = update_flags::retry;
                 }
 
-                if ( result == update_flags::retry && pNode->version( memory_model::memory_order_acquire ) != nVersion ) {
+                if ( result == update_flags::retry ) {
+                    if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
+                        return update_flags::retry;
                     m_stat.onRemoveRetry();
-                    return update_flags::retry;
                 }
-            } while ( result == update_flags::retry );
-            return result;
+                else
+                    return result;
+            }
         }
 
         template <typename K, typename Func>
@@ -1260,7 +1265,7 @@ namespace cds { namespace container {
 
             if ( c_bRelaxedInsert ) {
                 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion
-                     || child( pNode, nDir ) != nullptr ) 
+                     || child( pNode, nDir ) != nullptr )
                 {
                     m_stat.onInsertRetry();
                     return update_flags::retry;
@@ -1275,7 +1280,7 @@ namespace cds { namespace container {
                 node_scoped_lock l( m_Monitor, *pNode );
 
                 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion
-                     || child( pNode, nDir ) != nullptr ) 
+                     || child( pNode, nDir ) != nullptr )
                 {
                     if ( c_bRelaxedInsert ) {
                         mapped_type pVal = pNew->m_pValue.load( memory_model::memory_order_relaxed );
@@ -1308,13 +1313,16 @@ namespace cds { namespace container {
         }
 
         template <typename Func>
-        int try_update_node( Func funcUpdate, node_type * pNode, rcu_disposer& disp )
+        int try_update_node( Func funcUpdate, node_type * pNode, version_type nVersion, rcu_disposer& disp )
         {
             mapped_type pOld;
             assert( pNode != nullptr );
             {
                 node_scoped_lock l( m_Monitor, *pNode );
 
+                if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
+                    return update_flags::retry;
+
                 if ( pNode->is_unlinked( memory_model::memory_order_relaxed )) {
                     m_stat.onUpdateUnlinked();
                     return update_flags::retry;
@@ -1348,7 +1356,7 @@ namespace cds { namespace container {
             if ( !pNode->is_valued( atomics::memory_order_relaxed ) )
                 return update_flags::failed;
 
-            if ( child( pNode, left_child ) == nullptr || child( pNode, right_child ) == nullptr ) { 
+            if ( child( pNode, left_child ) == nullptr || child( pNode, right_child ) == nullptr ) {
                 node_type * pDamaged;
                 mapped_type pOld;
                 {
@@ -1360,7 +1368,7 @@ namespace cds { namespace container {
                         node_scoped_lock ln( m_Monitor, *pNode );
                         pOld = pNode->value( memory_model::memory_order_relaxed );
                         if ( !( pNode->version( memory_model::memory_order_acquire ) == nVersion
-                          && pOld 
+                          && pOld
                           && try_unlink_locked( pParent, pNode, disp )))
                         {
                             return update_flags::retry;
@@ -1434,7 +1442,7 @@ namespace cds { namespace container {
                 pParent->m_pRight.store( pSplice, memory_model::memory_order_relaxed );
 
             if ( pSplice )
-                pSplice->m_pParent.store( pParent, memory_model::memory_order_release );
+                pSplice->parent( pParent, memory_model::memory_order_relaxed );
 
             // Mark the node as unlinked
             pNode->version( node_type::unlinked, memory_model::memory_order_release );
@@ -1657,6 +1665,8 @@ namespace cds { namespace container {
 
         static void begin_change( node_type * pNode, version_type version )
         {
+            assert(pNode->version(memory_model::memory_order_acquire) == version );
+            assert( (version & node_type::shrinking) == 0 );
             pNode->version( version | node_type::shrinking, memory_model::memory_order_release );
         }
         static void end_change( node_type * pNode, version_type version )
@@ -1674,10 +1684,14 @@ namespace cds { namespace container {
 
             pNode->m_pLeft.store( pLRight, memory_model::memory_order_relaxed );
             if ( pLRight != nullptr )
-                pLRight->m_pParent.store( pNode, memory_model::memory_order_relaxed  );
+                pLRight->parent( pNode, memory_model::memory_order_relaxed  );
+
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             pLeft->m_pRight.store( pNode, memory_model::memory_order_relaxed );
-            pNode->m_pParent.store( pLeft, memory_model::memory_order_relaxed );
+            pNode->parent( pLeft, memory_model::memory_order_relaxed );
+
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             if ( pParentLeft == pNode )
                 pParent->m_pLeft.store( pLeft, memory_model::memory_order_relaxed );
@@ -1685,7 +1699,9 @@ namespace cds { namespace container {
                 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
                 pParent->m_pRight.store( pLeft, memory_model::memory_order_relaxed );
             }
-            pLeft->m_pParent.store( pParent, memory_model::memory_order_relaxed );
+            pLeft->parent( pParent, memory_model::memory_order_relaxed );
+
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             // fix up heights links
             int hNode = 1 + std::max( hLR, hR );
@@ -1705,6 +1721,7 @@ namespace cds { namespace container {
             int nodeBalance = hLR - hR;
             if ( nodeBalance < -1 || nodeBalance > 1 ) {
                 // we need another rotation at pNode
+                m_stat.onRotateAfterRightRotation();
                 return pNode;
             }
 
@@ -1712,17 +1729,22 @@ namespace cds { namespace container {
             // extra-routing node damage
             if ( (pLRight == nullptr || hR == 0) && !pNode->is_valued(memory_model::memory_order_relaxed)) {
                 // we need to remove pNode and then repair
+                m_stat.onRemoveAfterRightRotation();
                 return pNode;
             }
 
             // we've already fixed the height at pLeft, do we need a rotation here?
             int leftBalance = hLL - hNode;
-            if ( leftBalance < -1 || leftBalance > 1 )
+            if ( leftBalance < -1 || leftBalance > 1 ) {
+                m_stat.onRotateAfterRightRotation();
                 return pLeft;
+            }
 
             // pLeft might also have routing node damage (if pLeft.left was null)
-            if ( hLL == 0 && !pLeft->is_valued( memory_model::memory_order_relaxed ))
+            if ( hLL == 0 && !pLeft->is_valued(memory_model::memory_order_relaxed) ) {
+                m_stat.onDamageAfterRightRotation();
                 return pLeft;
+            }
 
             // try to fix the parent height while we've still got the lock
             return fix_height_locked( pParent );
@@ -1738,10 +1760,14 @@ namespace cds { namespace container {
             // fix up pNode links, careful to be compatible with concurrent traversal for all but pNode
             pNode->m_pRight.store( pRLeft, memory_model::memory_order_relaxed );
             if ( pRLeft != nullptr )
-                pRLeft->m_pParent.store( pNode, memory_model::memory_order_relaxed );
+                pRLeft->parent( pNode, memory_model::memory_order_relaxed );
+
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             pRight->m_pLeft.store( pNode, memory_model::memory_order_relaxed );
-            pNode->m_pParent.store( pRight, memory_model::memory_order_relaxed );
+            pNode->parent( pRight, memory_model::memory_order_relaxed );
+
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             if ( pParentLeft == pNode )
                 pParent->m_pLeft.store( pRight, memory_model::memory_order_relaxed );
@@ -1749,7 +1775,9 @@ namespace cds { namespace container {
                 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
                 pParent->m_pRight.store( pRight, memory_model::memory_order_relaxed );
             }
-            pRight->m_pParent.store( pParent, memory_model::memory_order_relaxed );
+            pRight->parent( pParent, memory_model::memory_order_relaxed );
+
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             // fix up heights
             int hNode = 1 + std::max( hL, hRL );
@@ -1760,18 +1788,26 @@ namespace cds { namespace container {
             m_stat.onRotateLeft();
 
             int nodeBalance = hRL - hL;
-            if ( nodeBalance < -1 || nodeBalance > 1 )
+            if ( nodeBalance < -1 || nodeBalance > 1 ) {
+                m_stat.onRotateAfterLeftRotation();
                 return pNode;
+            }
 
-            if ( (pRLeft == nullptr || hL == 0) && !pNode->is_valued( memory_model::memory_order_relaxed ))
+            if ( (pRLeft == nullptr || hL == 0) && !pNode->is_valued(memory_model::memory_order_relaxed) ) {
+                m_stat.onRemoveAfterLeftRotation();
                 return pNode;
+            }
 
             int rightBalance = hRR - hNode;
-            if ( rightBalance < -1 || rightBalance > 1 )
+            if ( rightBalance < -1 || rightBalance > 1 ) {
+                m_stat.onRotateAfterLeftRotation();
                 return pRight;
+            }
 
-            if ( hRR == 0 && !pRight->is_valued( memory_model::memory_order_relaxed ))
+            if ( hRR == 0 && !pRight->is_valued(memory_model::memory_order_relaxed) ) {
+                m_stat.onDamageAfterLeftRotation();
                 return pRight;
+            }
 
             return fix_height_locked( pParent );
         }
@@ -1792,16 +1828,21 @@ namespace cds { namespace container {
             // fix up pNode links, careful about the order!
             pNode->m_pLeft.store( pLRR, memory_model::memory_order_relaxed );
             if ( pLRR != nullptr )
-                pLRR->m_pParent.store( pNode, memory_model::memory_order_relaxed );
+                pLRR->parent( pNode, memory_model::memory_order_relaxed );
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             pLeft->m_pRight.store( pLRL, memory_model::memory_order_relaxed );
             if ( pLRL != nullptr )
-                pLRL->m_pParent.store( pLeft, memory_model::memory_order_relaxed );
+                pLRL->parent( pLeft, memory_model::memory_order_relaxed );
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             pLRight->m_pLeft.store( pLeft, memory_model::memory_order_relaxed );
-            pLeft->m_pParent.store( pLRight, memory_model::memory_order_relaxed );
+            pLeft->parent( pLRight, memory_model::memory_order_relaxed );
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
+
             pLRight->m_pRight.store( pNode, memory_model::memory_order_relaxed );
-            pNode->m_pParent.store( pLRight, memory_model::memory_order_relaxed );
+            pNode->parent( pLRight, memory_model::memory_order_relaxed );
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             if ( pPL == pNode )
                 pParent->m_pLeft.store( pLRight, memory_model::memory_order_relaxed );
@@ -1809,7 +1850,8 @@ namespace cds { namespace container {
                 assert( child( pParent, right_child ) == pNode );
                 pParent->m_pRight.store( pLRight, memory_model::memory_order_relaxed );
             }
-            pLRight->m_pParent.store( pParent, memory_model::memory_order_relaxed );
+            pLRight->parent( pParent, memory_model::memory_order_relaxed );
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             // fix up heights
             int hNode = 1 + std::max( hLRR, hR );
@@ -1837,19 +1879,23 @@ namespace cds { namespace container {
             int nodeBalance = hLRR - hR;
             if ( nodeBalance < -1 || nodeBalance > 1 ) {
                 // we need another rotation at pNode
+                m_stat.onRotateAfterRLRotation();
                 return pNode;
             }
 
             // pNode might also be damaged by being an unnecessary routing node
             if ( (pLRR == nullptr || hR == 0) && !pNode->is_valued( memory_model::memory_order_relaxed )) {
                 // repair involves splicing out pNode and maybe more rotations
+                m_stat.onRemoveAfterRLRotation();
                 return pNode;
             }
 
             // we've already fixed the height at pLRight, do we need a rotation here?
             int balanceLR = hLeft - hNode;
-            if ( balanceLR < -1 || balanceLR > 1 )
+            if ( balanceLR < -1 || balanceLR > 1 ) {
+                m_stat.onRotateAfterRLRotation();
                 return pLRight;
+            }
 
             // try to fix the parent height while we've still got the lock
             return fix_height_locked( pParent );
@@ -1871,16 +1917,21 @@ namespace cds { namespace container {
             // fix up pNode links, careful about the order!
             pNode->m_pRight.store( pRLL, memory_model::memory_order_relaxed );
             if ( pRLL != nullptr )
-                pRLL->m_pParent.store( pNode, memory_model::memory_order_relaxed );
+                pRLL->parent( pNode, memory_model::memory_order_relaxed );
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             pRight->m_pLeft.store( pRLR, memory_model::memory_order_relaxed );
             if ( pRLR != nullptr )
-                pRLR->m_pParent.store( pRight, memory_model::memory_order_relaxed );
+                pRLR->parent( pRight, memory_model::memory_order_relaxed );
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             pRLeft->m_pRight.store( pRight, memory_model::memory_order_relaxed );
-            pRight->m_pParent.store( pRLeft, memory_model::memory_order_relaxed );
+            pRight->parent( pRLeft, memory_model::memory_order_relaxed );
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
+
             pRLeft->m_pLeft.store( pNode, memory_model::memory_order_relaxed );
-            pNode->m_pParent.store( pRLeft, memory_model::memory_order_relaxed );
+            pNode->parent( pRLeft, memory_model::memory_order_relaxed );
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             if ( pPL == pNode )
                 pParent->m_pLeft.store( pRLeft, memory_model::memory_order_relaxed );
@@ -1888,7 +1939,8 @@ namespace cds { namespace container {
                 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
                 pParent->m_pRight.store( pRLeft, memory_model::memory_order_relaxed );
             }
-            pRLeft->m_pParent.store( pParent, memory_model::memory_order_relaxed );
+            pRLeft->parent( pParent, memory_model::memory_order_relaxed );
+            atomics::atomic_thread_fence( memory_model::memory_order_release );
 
             // fix up heights
             int hNode = 1 + std::max( hL, hRLL );
@@ -1904,14 +1956,21 @@ namespace cds { namespace container {
             assert( hRR - hRLR <= 1 && hRLR - hRR <= 1 );
 
             int nodeBalance = hRLL - hL;
-            if ( nodeBalance < -1 || nodeBalance > 1 )
+            if ( nodeBalance < -1 || nodeBalance > 1 ) {
+                m_stat.onRotateAfterLRRotation();
                 return pNode;
-            if ( (pRLL == nullptr || hL == 0) && !pNode->is_valued( memory_model::memory_order_relaxed ))
+            }
+
+            if ( (pRLL == nullptr || hL == 0) && !pNode->is_valued(memory_model::memory_order_relaxed) ) {
+                m_stat.onRemoveAfterLRRotation();
                 return pNode;
+            }
 
             int balRL = hRight - hNode;
-            if ( balRL < -1 || balRL > 1 )
+            if ( balRL < -1 || balRL > 1 ) {
+                m_stat.onRotateAfterLRRotation();
                 return pRLeft;
+            }
 
             return fix_height_locked( pParent );
         }