3 #ifndef CDSLIB_CONTAINER_IMPL_BRONSON_AVLTREE_MAP_RCU_H
4 #define CDSLIB_CONTAINER_IMPL_BRONSON_AVLTREE_MAP_RCU_H
6 #include <type_traits> // is_base_of
7 #include <cds/container/details/bronson_avltree_base.h>
8 #include <cds/urcu/details/check_deadlock.h>
9 #include <cds/urcu/exempt_ptr.h>
11 namespace cds { namespace container {
13 /// Bronson et al AVL-tree (RCU specialization for storing pointer to values)
14 /** @ingroup cds_nonintrusive_map
15 @ingroup cds_nonintrusive_tree
16 @headerfile cds/container/bronson_avltree_map_rcu.h
17 @anchor cds_container_BronsonAVLTreeMap_rcu_ptr
19 This is the specialization of \ref cds_container_BronsonAVLTreeMap_rcu "RCU-based Bronson et al AVL-tree"
20 for "key -> value pointer" map. This specialization stores the pointer to user-allocated values instead of the copy
21 of the value. When a tree node is removed, the algorithm does not free the value pointer directly, instead, it call
22 the disposer functor provided by \p Traits template parameter.
24 <b>Template arguments</b>:
25 - \p RCU - one of \ref cds_urcu_gc "RCU type"
27 - \p T - value type to be stored in tree's nodes. Note, the specialization stores the pointer to user-allocated
29 - \p Traits - tree traits, default is \p bronson_avltree::traits
30 It is possible to declare option-based tree with \p bronson_avltree::make_traits metafunction
31 instead of \p Traits template argument.
33 @note Before including <tt><cds/container/bronson_avltree_map_rcu.h></tt> you should include appropriate RCU header file,
34 see \ref cds_urcu_gc "RCU type" for list of existing RCU class and corresponding header files.
40 # ifdef CDS_DOXYGEN_INVOKED
41 typename Traits = bronson_avltree::traits
46 class BronsonAVLTreeMap< cds::urcu::gc<RCU>, Key, T*, Traits >
49 typedef cds::urcu::gc<RCU> gc; ///< RCU Garbage collector
50 typedef Key key_type; ///< type of a key stored in the map
51 typedef T * mapped_type; ///< type of value stored in the map
52 typedef Traits traits; ///< Traits template parameter
54 # ifdef CDS_DOXYGEN_INVOKED
55 typedef implementation_defined key_comparator; ///< key compare functor based on \p Traits::compare and \p Traits::less
57 typedef typename opt::details::make_comparator< key_type, traits >::type key_comparator;
59 typedef typename traits::item_counter item_counter; ///< Item counting policy
60 typedef typename traits::memory_model memory_model; ///< Memory ordering, see \p cds::opt::memory_model option
61 typedef typename traits::node_allocator node_allocator_type; ///< allocator for maintaining internal nodes
62 typedef typename traits::stat stat; ///< internal statistics
63 typedef typename traits::rcu_check_deadlock rcu_check_deadlock; ///< Deadlock checking policy
64 typedef typename traits::back_off back_off; ///< Back-off strategy
65 typedef typename traits::disposer disposer; ///< Value disposer
66 typedef typename traits::sync_monitor sync_monitor; ///< @ref cds_sync_monitor "Synchronization monitor" type for node-level locking
68 /// Enabled or disabled @ref bronson_avltree::relaxed_insert "relaxed insertion"
69 static CDS_CONSTEXPR bool const c_bRelaxedInsert = traits::relaxed_insert;
71 /// Group of \p extract_xxx functions does not require external locking
72 static CDS_CONSTEXPR const bool c_bExtractLockExternal = false;
74 # ifdef CDS_DOXYGEN_INVOKED
75 /// Returned pointer to \p mapped_type of extracted node
76 typedef cds::urcu::exempt_ptr< gc, T, T, disposer, void > exempt_ptr;
78 typedef cds::urcu::exempt_ptr< gc,
79 typename std::remove_pointer<mapped_type>::type,
80 typename std::remove_pointer<mapped_type>::type,
86 typedef typename gc::scoped_lock rcu_lock; ///< RCU scoped lock
90 typedef bronson_avltree::node< key_type, mapped_type, sync_monitor > node_type;
91 typedef typename node_type::version_type version_type;
93 typedef cds::details::Allocator< node_type, node_allocator_type > cxx_allocator;
94 typedef cds::urcu::details::check_deadlock_policy< gc, rcu_check_deadlock > check_deadlock_policy;
96 enum class find_result
113 result_inserted = allow_insert,
114 result_updated = allow_update,
121 nothing_required = -3,
122 rebalance_required = -2,
131 typedef typename sync_monitor::template scoped_lock<node_type> node_scoped_lock;
136 template <typename K>
137 static node_type * alloc_node( K&& key, int nHeight, version_type version, node_type * pParent, node_type * pLeft, node_type * pRight )
139 return cxx_allocator().New( std::forward<K>( key ), nHeight, version, pParent, pLeft, pRight );
142 static void free_node( node_type * pNode )
144 // Free node without disposer
145 assert( !pNode->is_valued( memory_model::memory_order_relaxed ));
146 assert( pNode->m_SyncMonitorInjection.check_free());
147 cxx_allocator().Delete( pNode );
150 static void free_value( mapped_type pVal )
155 static node_type * child( node_type * pNode, int nDir, atomics::memory_order order = memory_model::memory_order_relaxed )
157 return pNode->child( nDir ).load( order );
160 static node_type * parent( node_type * pNode, atomics::memory_order order = memory_model::memory_order_relaxed )
162 return pNode->parent( order );
168 node_type * m_pRetiredList; ///< head of retired node list
169 mapped_type m_pRetiredValue; ///< value retired
173 : m_pRetiredList( nullptr )
174 , m_pRetiredValue( nullptr )
182 void dispose( node_type * pNode )
184 assert( !pNode->is_valued( memory_model::memory_order_relaxed ));
185 pNode->m_pNextRemoved = m_pRetiredList;
186 m_pRetiredList = pNode;
189 void dispose_value( mapped_type pVal )
191 assert( m_pRetiredValue == nullptr );
192 m_pRetiredValue = pVal;
196 struct internal_disposer
198 void operator()( node_type * p ) const
206 assert( !gc::is_locked() );
208 // TODO: use RCU::batch_retire
211 for ( node_type * p = m_pRetiredList; p; ) {
212 node_type * pNext = static_cast<node_type *>( p->m_pNextRemoved );
213 // Value already disposed
214 gc::template retire_ptr<internal_disposer>( p );
219 if ( m_pRetiredValue )
220 gc::template retire_ptr<disposer>( m_pRetiredValue );
228 typename node_type::base_class m_Root;
230 item_counter m_ItemCounter;
231 mutable sync_monitor m_Monitor;
236 /// Creates empty map
238 : m_pRoot( static_cast<node_type *>( &m_Root ))
249 The \p key_type should be constructible from a value of type \p K.
251 RCU \p synchronize() can be called. RCU should not be locked.
253 Returns \p true if inserting successful, \p false otherwise.
255 template <typename K>
256 bool insert( K const& key, mapped_type pVal )
258 return do_update(key, key_comparator(),
259 [pVal]( node_type * pNode ) -> mapped_type
261 assert( pNode->m_pValue.load( memory_model::memory_order_relaxed ) == nullptr );
265 update_flags::allow_insert
266 ) == update_flags::result_inserted;
269 /// Updates the value for \p key
271 The operation performs inserting or updating the value for \p key with lock-free manner.
272 If \p bInsert is \p false, only updating of existing node is possible.
274 If \p key is not found and inserting is allowed (i.e. \p bInsert is \p true),
275 then the new node created from \p key will be inserted into the map; note that in this case the \ref key_type should be
276 constructible from type \p K.
277 Otherwise, the value for \p key will be changed to \p pVal.
279 RCU \p synchronize() method can be called. RCU should not be locked.
281 Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successfull,
282 \p second is \p true if new node has been added or \p false if the node with \p key
285 template <typename K>
286 std::pair<bool, bool> update( K const& key, mapped_type pVal, bool bInsert = true )
288 int result = do_update( key, key_comparator(),
289 [pVal]( node_type * ) -> mapped_type
293 update_flags::allow_update | (bInsert ? update_flags::allow_insert : 0)
295 return std::make_pair( result != 0, (result & update_flags::result_inserted) != 0 );
299 template <typename K>
300 std::pair<bool, bool> ensure( K const& key, mapped_type pVal )
302 return update( key, pVal, true );
307 /// Delete \p key from the map
309 RCU \p synchronize() method can be called. RCU should not be locked.
311 Return \p true if \p key is found and deleted, \p false otherwise
313 template <typename K>
314 bool erase( K const& key )
319 []( key_type const&, mapped_type pVal, rcu_disposer& disp ) -> bool { disp.dispose_value( pVal ); return true; }
323 /// Deletes the item from the map using \p pred predicate for searching
325 The function is an analog of \p erase(K const&)
326 but \p pred is used for key comparing.
327 \p Less functor has the interface like \p std::less.
328 \p Less must imply the same element order as the comparator used for building the map.
330 template <typename K, typename Less>
331 bool erase_with( K const& key, Less pred )
336 cds::opt::details::make_comparator_from_less<Less>(),
337 []( key_type const&, mapped_type pVal, rcu_disposer& disp ) -> bool { disp.dispose_value( pVal ); return true; }
341 /// Delete \p key from the map
343 The function searches an item with key \p key, calls \p f functor
344 and deletes the item. If \p key is not found, the functor is not called.
346 The functor \p Func interface:
349 void operator()( key_type const& key, std::remove_pointer<mapped_type>::type& val) { ... }
353 RCU \p synchronize method can be called. RCU should not be locked.
355 Return \p true if key is found and deleted, \p false otherwise
357 template <typename K, typename Func>
358 bool erase( K const& key, Func f )
363 [&f]( key_type const& key, mapped_type pVal, rcu_disposer& disp ) -> bool {
366 disp.dispose_value(pVal);
372 /// Deletes the item from the map using \p pred predicate for searching
374 The function is an analog of \p erase(K const&, Func)
375 but \p pred is used for key comparing.
376 \p Less functor has the interface like \p std::less.
377 \p Less must imply the same element order as the comparator used for building the map.
379 template <typename K, typename Less, typename Func>
380 bool erase_with( K const& key, Less pred, Func f )
385 cds::opt::details::make_comparator_from_less<Less>(),
386 [&f]( key_type const& key, mapped_type pVal, rcu_disposer& disp ) -> bool {
389 disp.dispose_value(pVal);
395 /// Extracts a value with minimal key from the map
397 Returns \p exempt_ptr to the leftmost item.
398 If the tree is empty, returns empty \p exempt_ptr.
400 Note that the function returns only the value for minimal key.
401 To retrieve its key use \p extract_min( Func ) member function.
403 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> minimum key.
404 It means that the function gets leftmost leaf of the tree and tries to unlink it.
405 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
406 So, the function returns the item with minimum key at the moment of tree traversing.
408 RCU \p synchronize method can be called. RCU should NOT be locked.
409 The function does not free the item.
410 The deallocator will be implicitly invoked when the returned object is destroyed or when
411 its \p release() member function is called.
413 exempt_ptr extract_min()
415 return exempt_ptr(do_extract_min( []( key_type const& ) {}));
418 /// Extracts minimal key key and corresponding value
420 Returns \p exempt_ptr to the leftmost item.
421 If the tree is empty, returns empty \p exempt_ptr.
423 \p Func functor is used to store minimal key.
424 \p Func has the following signature:
427 void operator()( key_type const& key );
430 If the tree is empty, \p f is not called.
431 Otherwise, is it called with minimal key, the pointer to corresponding value is returned
434 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> minimum key.
435 It means that the function gets leftmost leaf of the tree and tries to unlink it.
436 During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
437 So, the function returns the item with minimum key at the moment of tree traversing.
439 RCU \p synchronize method can be called. RCU should NOT be locked.
440 The function does not free the item.
441 The deallocator will be implicitly invoked when the returned object is destroyed or when
442 its \p release() member function is called.
444 template <typename Func>
445 exempt_ptr extract_min( Func f )
447 return exempt_ptr(do_extract_min( [&f]( key_type const& key ) { f(key); }));
450 /// Extracts minimal key key and corresponding value
452 This function is a shortcut for the following call:
455 exempt_ptr xp = theTree.extract_min( [&key]( key_type const& k ) { key = k; } );
457 \p key_type should be copy-assignable. The copy of minimal key
458 is returned in \p min_key argument.
460 typename std::enable_if< std::is_copy_assignable<key_type>::value, exempt_ptr >::type
461 extract_min_key( key_type& min_key )
463 return exempt_ptr(do_extract_min( [&min_key]( key_type const& key ) { min_key = key; }));
466 /// Extracts a value with maximal key from the tree
468 Returns \p exempt_ptr pointer to the rightmost item.
469 If the set is empty, returns empty \p exempt_ptr.
471 Note that the function returns only the value for maximal key.
472 To retrieve its key use \p extract_max( Func ) member function.
474 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> maximal key.
475 It means that the function gets rightmost leaf of the tree and tries to unlink it.
476 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
477 So, the function returns the item with maximum key at the moment of tree traversing.
479 RCU \p synchronize method can be called. RCU should NOT be locked.
480 The function does not free the item.
481 The deallocator will be implicitly invoked when the returned object is destroyed or when
482 its \p release() is called.
484 exempt_ptr extract_max()
486 return exempt_ptr(do_extract_max( []( key_type const& ) {}));
489 /// Extracts the maximal key and corresponding value
491 Returns \p exempt_ptr pointer to the rightmost item.
492 If the set is empty, returns empty \p exempt_ptr.
494 \p Func functor is used to store maximal key.
495 \p Func has the following signature:
498 void operator()( key_type const& key );
501 If the tree is empty, \p f is not called.
502 Otherwise, is it called with maximal key, the pointer to corresponding value is returned
505 @note Due the concurrent nature of the map, the function extracts <i>nearly</i> maximal key.
506 It means that the function gets rightmost leaf of the tree and tries to unlink it.
507 During unlinking, a concurrent thread may insert an item with key great than leftmost item's key.
508 So, the function returns the item with maximum key at the moment of tree traversing.
510 RCU \p synchronize method can be called. RCU should NOT be locked.
511 The function does not free the item.
512 The deallocator will be implicitly invoked when the returned object is destroyed or when
513 its \p release() is called.
515 template <typename Func>
516 exempt_ptr extract_max( Func f )
518 return exempt_ptr(do_extract_max( [&f]( key_type const& key ) { f(key); }));
521 /// Extracts the maximal key and corresponding value
523 This function is a shortcut for the following call:
526 exempt_ptr xp = theTree.extract_max( [&key]( key_type const& k ) { key = k; } );
528 \p key_type should be copy-assignable. The copy of maximal key
529 is returned in \p max_key argument.
531 typename std::enable_if< std::is_copy_assignable<key_type>::value, exempt_ptr >::type
532 extract_max_key( key_type& max_key )
534 return exempt_ptr(do_extract_max( [&max_key]( key_type const& key ) { max_key = key; }));
537 /// Extracts an item from the map
539 The function searches an item with key equal to \p key in the tree,
540 unlinks it, and returns \p exempt_ptr pointer to a value found.
541 If \p key is not found the function returns an empty \p exempt_ptr.
543 RCU \p synchronize method can be called. RCU should NOT be locked.
544 The function does not destroy the value found.
545 The disposer will be implicitly invoked when the returned object is destroyed or when
546 its \p release() member function is called.
548 template <typename Q>
549 exempt_ptr extract( Q const& key )
551 return exempt_ptr(do_extract( key ));
555 /// Extracts an item from the map using \p pred for searching
557 The function is an analog of \p extract(Q const&)
558 but \p pred is used for key compare.
559 \p Less has the interface like \p std::less.
560 \p pred must imply the same element order as the comparator used for building the tree.
562 template <typename Q, typename Less>
563 exempt_ptr extract_with( Q const& key, Less pred )
565 return exempt_ptr(do_extract_with( key, pred ));
568 /// Find the key \p key
570 The function searches the item with key equal to \p key and calls the functor \p f for item found.
571 The interface of \p Func functor is:
574 void operator()( key_type const& key, mapped_type& item );
577 where \p item is the item found.
578 The functor is called under node-level lock.
580 The function applies RCU lock internally.
582 The function returns \p true if \p key is found, \p false otherwise.
584 template <typename K, typename Func>
585 bool find( K const& key, Func f )
587 return do_find( key, key_comparator(),
588 [&f]( node_type * pNode ) -> bool {
589 assert( pNode != nullptr );
590 mapped_type pVal = pNode->m_pValue.load( memory_model::memory_order_relaxed );
592 f( pNode->m_key, *pVal );
600 /// Finds the key \p val using \p pred predicate for searching
602 The function is an analog of \p find(K const&, Func)
603 but \p pred is used for key comparing.
604 \p Less functor has the interface like \p std::less.
605 \p Less must imply the same element order as the comparator used for building the map.
607 template <typename K, typename Less, typename Func>
608 bool find_with( K const& key, Less pred, Func f )
611 return do_find( key, cds::opt::details::make_comparator_from_less<Less>(),
612 [&f]( node_type * pNode ) -> bool {
613 assert( pNode != nullptr );
614 mapped_type pVal = pNode->m_pValue.load( memory_model::memory_order_relaxed );
616 f( pNode->m_key, *pVal );
624 /// Find the key \p key
626 The function searches the item with key equal to \p key
627 and returns \p true if it is found, and \p false otherwise.
629 The function applies RCU lock internally.
631 template <typename K>
632 bool find( K const& key )
634 return do_find( key, key_comparator(), []( node_type * ) -> bool { return true; });
637 /// Finds the key \p val using \p pred predicate for searching
639 The function is an analog of \p find(K const&)
640 but \p pred is used for key comparing.
641 \p Less functor has the interface like \p std::less.
642 \p Less must imply the same element order as the comparator used for building the map.
644 template <typename K, typename Less>
645 bool find_with( K const& key, Less pred )
648 return do_find( key, cds::opt::details::make_comparator_from_less<Less>(), []( node_type * ) -> bool { return true; } );
651 /// Clears the tree (thread safe, not atomic)
653 The function unlink all items from the tree.
654 The function is thread safe but not atomic: in multi-threaded environment with parallel insertions
658 assert( set.empty() );
660 the assertion could be raised.
662 For each node the \ref disposer will be called after unlinking.
664 RCU \p synchronize method can be called. RCU should not be locked.
668 while ( extract_min() );
671 /// Clears the tree (not thread safe)
673 This function is not thread safe and may be called only when no other thread deals with the tree.
674 The function is used in the tree destructor.
678 clear(); // temp solution
682 /// Checks if the map is empty
685 return m_Root.m_pRight.load( memory_model::memory_order_relaxed ) == nullptr;
688 /// Returns item count in the map
690 Only leaf nodes containing user data are counted.
692 The value returned depends on item counter type provided by \p Traits template parameter.
693 If it is \p atomicity::empty_item_counter this function always returns 0.
695 The function is not suitable for checking the tree emptiness, use \p empty()
696 member function for this purpose.
700 return m_ItemCounter;
703 /// Returns const reference to internal statistics
704 stat const& statistics() const
709 /// Returns reference to \p sync_monitor object
710 sync_monitor& monitor()
715 sync_monitor const& monitor() const
721 /// Checks internal consistency (not atomic, not thread-safe)
723 The debugging function to check internal consistency of the tree.
725 bool check_consistency() const
727 return check_consistency([]( size_t /*nLevel*/, size_t /*hLeft*/, size_t /*hRight*/ ){} );
730 /// Checks internal consistency (not atomic, not thread-safe)
732 The debugging function to check internal consistency of the tree.
733 The functor \p Func is called if a violation of internal tree structure
737 void operator()( size_t nLevel, size_t hLeft, size_t hRight );
741 - \p nLevel - the level where the violation is found
742 - \p hLeft - the height of left subtree
743 - \p hRight - the height of right subtree
745 The functor is called for each violation found.
747 template <typename Func>
748 bool check_consistency( Func f ) const
750 node_type * pChild = child( m_pRoot, right_child );
753 do_check_consistency( pChild, 1, f, nErrors );
761 template <typename Func>
762 size_t do_check_consistency( node_type * pNode, size_t nLevel, Func f, size_t& nErrors ) const
766 node_type * pLeft = child( pNode, left_child );
767 node_type * pRight = child( pNode, right_child );
768 if ( pLeft && cmp( pLeft->m_key, pNode->m_key ) > 0 )
770 if ( pRight && cmp( pNode->m_key, pRight->m_key ) > 0 )
773 size_t hLeft = do_check_consistency( pLeft, nLevel + 1, f, nErrors );
774 size_t hRight = do_check_consistency( pRight, nLevel + 1, f, nErrors );
776 if ( hLeft >= hRight ) {
777 if ( hLeft - hRight > 1 ) {
778 f( nLevel, hLeft, hRight );
784 if ( hRight - hLeft > 1 ) {
785 f( nLevel, hLeft, hRight );
794 template <typename Q, typename Compare, typename Func>
795 bool do_find( Q& key, Compare cmp, Func f ) const
800 result = try_find( key, cmp, f, m_pRoot, right_child, 0 );
802 assert( result != find_result::retry );
803 return result == find_result::found;
806 template <typename K, typename Compare, typename Func>
807 int do_update( K const& key, Compare cmp, Func funcUpdate, int nFlags )
809 check_deadlock_policy::check();
811 rcu_disposer removed_list;
814 return try_update_root( key, cmp, nFlags, funcUpdate, removed_list );
818 template <typename K, typename Compare, typename Func>
819 bool do_remove( K const& key, Compare cmp, Func func )
821 // Func must return true if the value was disposed
822 // or false if the value was extracted
824 check_deadlock_policy::check();
826 rcu_disposer removed_list;
829 return try_remove_root( key, cmp, func, removed_list );
833 template <typename Func>
834 mapped_type do_extract_min( Func f )
836 mapped_type pExtracted = nullptr;
839 [&pExtracted, &f]( key_type const& key, mapped_type pVal, rcu_disposer& ) -> bool { f( key ); pExtracted = pVal; return false; }
844 template <typename Func>
845 mapped_type do_extract_max( Func f )
847 mapped_type pExtracted = nullptr;
850 [&pExtracted, &f]( key_type const& key, mapped_type pVal, rcu_disposer& ) -> bool { f( key ); pExtracted = pVal; return false; }
855 template <typename Func>
856 void do_extract_minmax( int nDir, Func func )
858 check_deadlock_policy::check();
860 rcu_disposer removed_list;
867 // get right child of root
868 node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
870 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
871 if ( nChildVersion & node_type::shrinking ) {
872 m_stat.onRemoveRootWaitShrinking();
873 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
874 result = update_flags::retry;
876 else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire )) {
877 result = try_extract_minmax( nDir, func, m_pRoot, pChild, nChildVersion, removed_list );
880 result = update_flags::retry;
885 if ( result == update_flags::retry )
886 m_stat.onRemoveRetry();
891 template <typename Q>
892 mapped_type do_extract( Q const& key )
894 mapped_type pExtracted = nullptr;
898 [&pExtracted]( key_type const&, mapped_type pVal, rcu_disposer& ) -> bool { pExtracted = pVal; return false; }
903 template <typename Q, typename Less>
904 mapped_type do_extract_with( Q const& key, Less pred )
907 mapped_type pExtracted = nullptr;
910 cds::opt::details::make_comparator_from_less<Less>(),
911 [&pExtracted]( key_type const&, mapped_type pVal, rcu_disposer& ) -> bool { pExtracted = pVal; return false; }
919 static int height( node_type * pNode, atomics::memory_order order = memory_model::memory_order_relaxed )
922 return pNode->m_nHeight.load( order );
924 static void set_height( node_type * pNode, int h, atomics::memory_order order = memory_model::memory_order_relaxed )
927 pNode->m_nHeight.store( h, order );
929 static int height_null( node_type * pNode, atomics::memory_order order = memory_model::memory_order_relaxed )
931 return pNode ? height( pNode, order ) : 0;
934 template <typename Q, typename Compare, typename Func>
935 find_result try_find( Q const& key, Compare cmp, Func f, node_type * pNode, int nDir, version_type nVersion ) const
937 assert( gc::is_locked() );
941 node_type * pChild = child( pNode, nDir );
943 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
944 return find_result::retry;
946 m_stat.onFindFailed();
947 return find_result::not_found;
950 int nCmp = cmp( key, pChild->m_key );
952 if ( pChild->is_valued( memory_model::memory_order_relaxed ) ) {
954 node_scoped_lock l( m_Monitor, *pChild );
955 if ( pChild->is_valued( memory_model::memory_order_relaxed )) {
957 m_stat.onFindSuccess();
958 return find_result::found;
963 m_stat.onFindFailed();
964 return find_result::not_found;
967 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
968 if ( nChildVersion & node_type::shrinking ) {
969 m_stat.onFindWaitShrinking();
970 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
972 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
973 return find_result::retry;
975 else if ( nChildVersion != node_type::unlinked && child( pNode, nDir ) == pChild )
977 if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
978 return find_result::retry;
980 find_result found = try_find( key, cmp, f, pChild, nCmp, nChildVersion );
981 if ( found != find_result::retry )
985 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
986 return find_result::retry;
988 m_stat.onFindRetry();
992 template <typename K, typename Compare, typename Func>
993 int try_update_root( K const& key, Compare cmp, int nFlags, Func funcUpdate, rcu_disposer& disp )
995 assert( gc::is_locked() );
1000 // get right child of root
1001 node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
1003 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1004 if ( nChildVersion & node_type::shrinking ) {
1005 m_stat.onUpdateRootWaitShrinking();
1006 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1007 result = update_flags::retry;
1009 else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire ))
1010 result = try_update( key, cmp, nFlags, funcUpdate, pChild, nChildVersion, disp );
1012 result = update_flags::retry;
1015 // the tree is empty
1016 if ( nFlags & update_flags::allow_insert ) {
1017 // insert into tree as right child of the root
1019 node_scoped_lock l( m_Monitor, *m_pRoot );
1020 if ( child( m_pRoot, right_child, memory_model::memory_order_acquire ) != nullptr ) {
1021 result = update_flags::retry;
1025 node_type * pNew = alloc_node( key, 1, 0, m_pRoot, nullptr, nullptr );
1026 mapped_type pVal = funcUpdate( pNew );
1027 assert( pVal != nullptr );
1028 pNew->m_pValue.store( pVal, memory_model::memory_order_release );
1030 m_pRoot->child( pNew, right_child, memory_model::memory_order_relaxed );
1031 set_height( m_pRoot, 2 );
1035 m_stat.onInsertSuccess();
1036 return update_flags::result_inserted;
1039 return update_flags::failed;
1042 if ( result == update_flags::retry )
1043 m_stat.onUpdateRetry();
1049 template <typename K, typename Compare, typename Func>
1050 bool try_remove_root( K const& key, Compare cmp, Func func, rcu_disposer& disp )
1052 assert( gc::is_locked() );
1057 // get right child of root
1058 node_type * pChild = child( m_pRoot, right_child, memory_model::memory_order_acquire );
1060 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1061 if ( nChildVersion & node_type::shrinking ) {
1062 m_stat.onRemoveRootWaitShrinking();
1063 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1064 result = update_flags::retry;
1066 else if ( pChild == child( m_pRoot, right_child, memory_model::memory_order_acquire )) {
1067 result = try_remove( key, cmp, func, m_pRoot, pChild, nChildVersion, disp );
1070 result = update_flags::retry;
1075 if ( result == update_flags::retry )
1076 m_stat.onRemoveRetry();
1078 return result == update_flags::result_removed;
1082 template <typename K, typename Compare, typename Func>
1083 int try_update( K const& key, Compare cmp, int nFlags, Func funcUpdate, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1085 assert( gc::is_locked() );
1086 assert( nVersion != node_type::unlinked );
1088 int nCmp = cmp( key, pNode->m_key );
1090 if ( nFlags & update_flags::allow_update )
1091 return try_update_node( funcUpdate, pNode, nVersion, disp );
1092 return update_flags::failed;
1097 node_type * pChild = child( pNode, nCmp );
1098 if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
1099 return update_flags::retry;
1101 if ( pChild == nullptr ) {
1103 if ( nFlags & update_flags::allow_insert )
1104 result = try_insert_node( key, funcUpdate, pNode, nCmp, nVersion, disp );
1106 result = update_flags::failed;
1110 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1111 if ( nChildVersion & node_type::shrinking ) {
1112 m_stat.onUpdateWaitShrinking();
1113 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1115 result = update_flags::retry;
1117 else if ( pChild == child( pNode, nCmp )) {
1118 // this second read is important, because it is protected by nChildVersion
1120 // validate the read that our caller took to get to node
1121 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1122 return update_flags::retry;
1124 // At this point we know that the traversal our parent took to get to node is still valid.
1125 // The recursive implementation will validate the traversal from node to
1126 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1127 // This means that we are no longer vulnerable to node shrinks, and we don't need
1128 // to validate node version any more.
1129 result = try_update( key, cmp, nFlags, funcUpdate, pChild, nChildVersion, disp );
1132 result = update_flags::retry;
1135 if ( result == update_flags::retry ) {
1136 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1137 return update_flags::retry;
1138 m_stat.onUpdateRetry();
1145 template <typename K, typename Compare, typename Func>
1146 int try_remove( K const& key, Compare cmp, Func func, node_type * pParent, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1148 assert( gc::is_locked() );
1149 assert( nVersion != node_type::unlinked );
1151 int nCmp = cmp( key, pNode->m_key );
1153 return try_remove_node( pParent, pNode, nVersion, func, disp );
1158 node_type * pChild = child( pNode, nCmp );
1159 if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
1160 return update_flags::retry;
1162 if ( pChild == nullptr )
1163 return update_flags::failed;
1166 result = update_flags::retry;
1167 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1168 if ( nChildVersion & node_type::shrinking ) {
1169 m_stat.onRemoveWaitShrinking();
1170 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1172 result = update_flags::retry;
1174 else if ( pChild == child( pNode, nCmp )) {
1175 // this second read is important, because it is protected by nChildVersion
1177 // validate the read that our caller took to get to node
1178 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1179 return update_flags::retry;
1181 // At this point we know that the traversal our parent took to get to node is still valid.
1182 // The recursive implementation will validate the traversal from node to
1183 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1184 // This means that we are no longer vulnerable to node shrinks, and we don't need
1185 // to validate node version any more.
1186 result = try_remove( key, cmp, func, pNode, pChild, nChildVersion, disp );
1189 result = update_flags::retry;
1192 if ( result == update_flags::retry ) {
1193 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1194 return update_flags::retry;
1195 m_stat.onRemoveRetry();
1202 template <typename Func>
1203 int try_extract_minmax( int nDir, Func func, node_type * pParent, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1205 assert( gc::is_locked() );
1206 assert( nVersion != node_type::unlinked );
1210 node_type * pChild = child( pNode, nDir );
1211 if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
1212 return update_flags::retry;
1214 if ( pChild == nullptr ) {
1216 return try_remove_node( pParent, pNode, nVersion, func, disp );
1219 //result = update_flags::retry;
1220 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1221 if ( nChildVersion & node_type::shrinking ) {
1222 m_stat.onRemoveWaitShrinking();
1223 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1225 result = update_flags::retry;
1227 else if ( pChild == child( pNode, nDir )) {
1228 // this second read is important, because it is protected by nChildVersion
1230 // validate the read that our caller took to get to node
1231 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1232 return update_flags::retry;
1234 // At this point we know that the traversal our parent took to get to node is still valid.
1235 // The recursive implementation will validate the traversal from node to
1236 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1237 // This means that we are no longer vulnerable to node shrinks, and we don't need
1238 // to validate node version any more.
1239 result = try_extract_minmax( nDir, func, pNode, pChild, nChildVersion, disp );
1242 result = update_flags::retry;
1245 if ( result == update_flags::retry ) {
1246 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1247 return update_flags::retry;
1248 m_stat.onRemoveRetry();
1255 template <typename K, typename Func>
1256 int try_insert_node( K const& key, Func funcUpdate, node_type * pNode, int nDir, version_type nVersion, rcu_disposer& disp )
1260 auto fnCreateNode = [&funcUpdate]( node_type * pNew ) {
1261 mapped_type pVal = funcUpdate( pNew );
1262 assert( pVal != nullptr );
1263 pNew->m_pValue.store( pVal, memory_model::memory_order_relaxed );
1266 if ( c_bRelaxedInsert ) {
1267 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion
1268 || child( pNode, nDir ) != nullptr )
1270 m_stat.onInsertRetry();
1271 return update_flags::retry;
1274 fnCreateNode( pNew = alloc_node( key, 1, 0, pNode, nullptr, nullptr ));
1277 node_type * pDamaged;
1279 assert( pNode != nullptr );
1280 node_scoped_lock l( m_Monitor, *pNode );
1282 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion
1283 || child( pNode, nDir ) != nullptr )
1285 if ( c_bRelaxedInsert ) {
1286 mapped_type pVal = pNew->m_pValue.load( memory_model::memory_order_relaxed );
1287 pNew->m_pValue.store( nullptr, memory_model::memory_order_relaxed );
1290 m_stat.onRelaxedInsertFailed();
1293 m_stat.onInsertRetry();
1294 return update_flags::retry;
1297 if ( !c_bRelaxedInsert )
1298 fnCreateNode( pNew = alloc_node( key, 1, 0, pNode, nullptr, nullptr ));
1300 pNode->child( pNew, nDir, memory_model::memory_order_relaxed );
1301 pDamaged = fix_height_locked( pNode );
1305 m_stat.onInsertSuccess();
1308 fix_height_and_rebalance( pDamaged, disp );
1309 m_stat.onInsertRebalanceRequired();
1312 return update_flags::result_inserted;
1315 template <typename Func>
1316 int try_update_node( Func funcUpdate, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1319 assert( pNode != nullptr );
1321 node_scoped_lock l( m_Monitor, *pNode );
1323 if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
1324 return update_flags::retry;
1326 if ( pNode->is_unlinked( memory_model::memory_order_relaxed )) {
1327 m_stat.onUpdateUnlinked();
1328 return update_flags::retry;
1331 pOld = pNode->value( memory_model::memory_order_relaxed );
1332 mapped_type pVal = funcUpdate( pNode );
1336 assert( pVal != nullptr );
1337 pNode->m_pValue.store( pVal, memory_model::memory_order_relaxed );
1342 disp.dispose_value(pOld);
1343 m_stat.onDisposeValue();
1346 m_stat.onUpdateSuccess();
1347 return update_flags::result_updated;
1350 template <typename Func>
1351 int try_remove_node( node_type * pParent, node_type * pNode, version_type nVersion, Func func, rcu_disposer& disp )
1353 assert( pParent != nullptr );
1354 assert( pNode != nullptr );
1356 if ( !pNode->is_valued( atomics::memory_order_relaxed ) )
1357 return update_flags::failed;
1359 if ( child( pNode, left_child ) == nullptr || child( pNode, right_child ) == nullptr ) {
1360 node_type * pDamaged;
1363 node_scoped_lock lp( m_Monitor, *pParent );
1364 if ( pParent->is_unlinked( atomics::memory_order_relaxed ) || parent( pNode ) != pParent )
1365 return update_flags::retry;
1368 node_scoped_lock ln( m_Monitor, *pNode );
1369 pOld = pNode->value( memory_model::memory_order_relaxed );
1370 if ( !( pNode->version( memory_model::memory_order_acquire ) == nVersion
1372 && try_unlink_locked( pParent, pNode, disp )))
1374 return update_flags::retry;
1377 pDamaged = fix_height_locked( pParent );
1381 if ( func( pNode->m_key, pOld, disp )) // calls pOld disposer inside
1382 m_stat.onDisposeValue();
1384 m_stat.onExtractValue();
1387 fix_height_and_rebalance( pDamaged, disp );
1388 m_stat.onRemoveRebalanceRequired();
1390 return update_flags::result_removed;
1393 int result = update_flags::retry;
1396 node_scoped_lock ln( m_Monitor, *pNode );
1397 pOld = pNode->value( atomics::memory_order_relaxed );
1398 if ( pNode->version( atomics::memory_order_acquire ) == nVersion && pOld ) {
1399 pNode->m_pValue.store( nullptr, atomics::memory_order_relaxed );
1400 result = update_flags::result_removed;
1404 if ( result == update_flags::result_removed ) {
1406 if ( func( pNode->m_key, pOld, disp )) // calls pOld disposer inside
1407 m_stat.onDisposeValue();
1409 m_stat.onExtractValue();
1416 bool try_unlink_locked( node_type * pParent, node_type * pNode, rcu_disposer& disp )
1418 // pParent and pNode must be locked
1419 assert( !pParent->is_unlinked(memory_model::memory_order_relaxed) );
1421 node_type * pParentLeft = child( pParent, left_child );
1422 node_type * pParentRight = child( pParent, right_child );
1423 if ( pNode != pParentLeft && pNode != pParentRight ) {
1424 // node is no longer a child of parent
1428 assert( !pNode->is_unlinked( memory_model::memory_order_relaxed ) );
1429 assert( pParent == parent( pNode ));
1431 node_type * pLeft = child( pNode, left_child );
1432 node_type * pRight = child( pNode, right_child );
1433 if ( pLeft != nullptr && pRight != nullptr ) {
1434 // splicing is no longer possible
1437 node_type * pSplice = pLeft ? pLeft : pRight;
1439 if ( pParentLeft == pNode )
1440 pParent->m_pLeft.store( pSplice, memory_model::memory_order_relaxed );
1442 pParent->m_pRight.store( pSplice, memory_model::memory_order_relaxed );
1445 pSplice->parent( pParent, memory_model::memory_order_relaxed );
1447 // Mark the node as unlinked
1448 pNode->version( node_type::unlinked, memory_model::memory_order_release );
1450 // The value will be disposed by calling function
1451 pNode->m_pValue.store( nullptr, memory_model::memory_order_relaxed );
1453 disp.dispose( pNode );
1454 m_stat.onDisposeNode();
1461 private: // rotations
1463 int estimate_node_condition( node_type * pNode )
1465 node_type * pLeft = child( pNode, left_child );
1466 node_type * pRight = child( pNode, right_child );
1468 if ( (pLeft == nullptr || pRight == nullptr) && !pNode->is_valued( memory_model::memory_order_relaxed ))
1469 return unlink_required;
1471 int h = height( pNode );
1472 int hL = height_null( pLeft );
1473 int hR = height_null( pRight );
1475 int hNew = 1 + std::max( hL, hR );
1476 int nBalance = hL - hR;
1478 if ( nBalance < -1 || nBalance > 1 )
1479 return rebalance_required;
1481 return h != hNew ? hNew : nothing_required;
1484 node_type * fix_height( node_type * pNode )
1486 assert( pNode != nullptr );
1487 node_scoped_lock l( m_Monitor, *pNode );
1488 return fix_height_locked( pNode );
1491 node_type * fix_height_locked( node_type * pNode )
1493 // pNode must be locked!!!
1494 int h = estimate_node_condition( pNode );
1496 case rebalance_required:
1497 case unlink_required:
1499 case nothing_required:
1502 set_height( pNode, h );
1503 return parent( pNode );
1507 void fix_height_and_rebalance( node_type * pNode, rcu_disposer& disp )
1509 while ( pNode && parent( pNode )) {
1510 int nCond = estimate_node_condition( pNode );
1511 if ( nCond == nothing_required || pNode->is_unlinked( memory_model::memory_order_relaxed ) )
1514 if ( nCond != unlink_required && nCond != rebalance_required )
1515 pNode = fix_height( pNode );
1517 node_type * pParent = parent( pNode );
1518 assert( pParent != nullptr );
1520 node_scoped_lock lp( m_Monitor, *pParent );
1521 if ( !pParent->is_unlinked( memory_model::memory_order_relaxed ) && parent( pNode ) == pParent ) {
1522 node_scoped_lock ln( m_Monitor, *pNode );
1523 pNode = rebalance_locked( pParent, pNode, disp );
1530 node_type * rebalance_locked( node_type * pParent, node_type * pNode, rcu_disposer& disp )
1532 // pParent and pNode should be locked.
1533 // Returns a damaged node, or nullptr if no more rebalancing is necessary
1534 assert( parent( pNode ) == pParent );
1536 node_type * pLeft = child( pNode, left_child );
1537 node_type * pRight = child( pNode, right_child );
1539 if ( (pLeft == nullptr || pRight == nullptr) && !pNode->is_valued( memory_model::memory_order_relaxed )) {
1540 if ( try_unlink_locked( pParent, pNode, disp ))
1541 return fix_height_locked( pParent );
1543 // retry needed for pNode
1548 assert( child( pParent, left_child ) == pNode || child( pParent, right_child ) == pNode );
1550 int h = height( pNode );
1551 int hL = height_null( pLeft );
1552 int hR = height_null( pRight );
1553 int hNew = 1 + std::max( hL, hR );
1554 int balance = hL - hR;
1557 return rebalance_to_right_locked( pParent, pNode, pLeft, hR );
1558 else if ( balance < -1 )
1559 return rebalance_to_left_locked( pParent, pNode, pRight, hL );
1560 else if ( hNew != h ) {
1561 set_height( pNode, hNew );
1563 // pParent is already locked
1564 return fix_height_locked( pParent );
1570 node_type * rebalance_to_right_locked( node_type * pParent, node_type * pNode, node_type * pLeft, int hR )
1572 assert( parent( pNode ) == pParent );
1573 assert( child( pParent, left_child ) == pNode || child( pParent, right_child ) == pNode );
1575 // pParent and pNode is locked yet
1576 // pNode->pLeft is too large, we will rotate-right.
1577 // If pLeft->pRight is taller than pLeft->pLeft, then we will first rotate-left pLeft.
1580 assert( pLeft != nullptr );
1581 node_scoped_lock l( m_Monitor, *pLeft );
1582 if ( pNode->m_pLeft.load( memory_model::memory_order_relaxed ) != pLeft )
1583 return pNode; // retry for pNode
1585 int hL = height( pLeft );
1587 return pNode; // retry
1589 node_type * pLRight = child( pLeft, right_child );
1590 int hLR = height_null( pLRight );
1591 node_type * pLLeft = child( pLeft, left_child );
1592 int hLL = height_null( pLLeft );
1596 return rotate_right_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLR );
1599 assert( pLRight != nullptr );
1601 node_scoped_lock lr( m_Monitor, *pLRight );
1602 if ( pLeft->m_pRight.load( memory_model::memory_order_relaxed ) != pLRight )
1603 return pNode; // retry
1605 hLR = height( pLRight );
1607 return rotate_right_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLR );
1609 int hLRL = height_null( child( pLRight, left_child ));
1610 int balance = hLL - hLRL;
1611 if ( balance >= -1 && balance <= 1 && !((hLL == 0 || hLRL == 0) && !pLeft->is_valued(memory_model::memory_order_relaxed))) {
1612 // nParent.child.left won't be damaged after a double rotation
1613 return rotate_right_over_left_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLRL );
1617 // focus on pLeft, if necessary pNode will be balanced later
1618 return rebalance_to_left_locked( pNode, pLeft, pLRight, hLL );
1623 node_type * rebalance_to_left_locked( node_type * pParent, node_type * pNode, node_type * pRight, int hL )
1625 assert( parent( pNode ) == pParent );
1626 assert( child( pParent, left_child ) == pNode || child( pParent, right_child ) == pNode );
1628 // pParent and pNode is locked yet
1630 assert( pRight != nullptr );
1631 node_scoped_lock l( m_Monitor, *pRight );
1632 if ( pNode->m_pRight.load( memory_model::memory_order_relaxed ) != pRight )
1633 return pNode; // retry for pNode
1635 int hR = height( pRight );
1636 if ( hL - hR >= -1 )
1637 return pNode; // retry
1639 node_type * pRLeft = child( pRight, left_child );
1640 int hRL = height_null( pRLeft );
1641 node_type * pRRight = child( pRight, right_child );
1642 int hRR = height_null( pRRight );
1644 return rotate_left_locked( pParent, pNode, hL, pRight, pRLeft, hRL, hRR );
1647 assert( pRLeft != nullptr );
1648 node_scoped_lock lrl( m_Monitor, *pRLeft );
1649 if ( pRight->m_pLeft.load( memory_model::memory_order_relaxed ) != pRLeft )
1650 return pNode; // retry
1652 hRL = height( pRLeft );
1654 return rotate_left_locked( pParent, pNode, hL, pRight, pRLeft, hRL, hRR );
1656 node_type * pRLRight = child( pRLeft, right_child );
1657 int hRLR = height_null( pRLRight );
1658 int balance = hRR - hRLR;
1659 if ( balance >= -1 && balance <= 1 && !((hRR == 0 || hRLR == 0) && !pRight->is_valued( memory_model::memory_order_relaxed )))
1660 return rotate_left_over_right_locked( pParent, pNode, hL, pRight, pRLeft, hRR, hRLR );
1662 return rebalance_to_right_locked( pNode, pRight, pRLeft, hRR );
1666 static void begin_change( node_type * pNode, version_type version )
1668 assert(pNode->version(memory_model::memory_order_acquire) == version );
1669 assert( (version & node_type::shrinking) == 0 );
1670 pNode->version( version | node_type::shrinking, memory_model::memory_order_release );
1672 static void end_change( node_type * pNode, version_type version )
1674 // Clear shrinking and unlinked flags and increment version
1675 pNode->version( (version | node_type::version_flags) + 1, memory_model::memory_order_release );
1678 node_type * rotate_right_locked( node_type * pParent, node_type * pNode, node_type * pLeft, int hR, int hLL, node_type * pLRight, int hLR )
1680 version_type nodeVersion = pNode->version( memory_model::memory_order_acquire );
1681 node_type * pParentLeft = child( pParent, left_child );
1683 begin_change( pNode, nodeVersion );
1685 pNode->m_pLeft.store( pLRight, memory_model::memory_order_relaxed );
1686 if ( pLRight != nullptr )
1687 pLRight->parent( pNode, memory_model::memory_order_relaxed );
1689 atomics::atomic_thread_fence( memory_model::memory_order_release );
1691 pLeft->m_pRight.store( pNode, memory_model::memory_order_relaxed );
1692 pNode->parent( pLeft, memory_model::memory_order_relaxed );
1694 atomics::atomic_thread_fence( memory_model::memory_order_release );
1696 if ( pParentLeft == pNode )
1697 pParent->m_pLeft.store( pLeft, memory_model::memory_order_relaxed );
1699 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1700 pParent->m_pRight.store( pLeft, memory_model::memory_order_relaxed );
1702 pLeft->parent( pParent, memory_model::memory_order_relaxed );
1704 atomics::atomic_thread_fence( memory_model::memory_order_release );
1706 // fix up heights links
1707 int hNode = 1 + std::max( hLR, hR );
1708 set_height( pNode, hNode );
1709 set_height( pLeft, 1 + std::max( hLL, hNode ));
1711 end_change( pNode, nodeVersion );
1712 m_stat.onRotateRight();
1714 // We have damaged pParent, pNode (now parent.child.right), and pLeft (now
1715 // parent.child). pNode is the deepest. Perform as many fixes as we can
1716 // with the locks we've got.
1718 // We've already fixed the height for pNode, but it might still be outside
1719 // our allowable balance range. In that case a simple fix_height_locked()
1721 int nodeBalance = hLR - hR;
1722 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1723 // we need another rotation at pNode
1724 m_stat.onRotateAfterRightRotation();
1728 // we've fixed balance and height damage for pNode, now handle
1729 // extra-routing node damage
1730 if ( (pLRight == nullptr || hR == 0) && !pNode->is_valued(memory_model::memory_order_relaxed)) {
1731 // we need to remove pNode and then repair
1732 m_stat.onRemoveAfterRightRotation();
1736 // we've already fixed the height at pLeft, do we need a rotation here?
1737 int leftBalance = hLL - hNode;
1738 if ( leftBalance < -1 || leftBalance > 1 ) {
1739 m_stat.onRotateAfterRightRotation();
1743 // pLeft might also have routing node damage (if pLeft.left was null)
1744 if ( hLL == 0 && !pLeft->is_valued(memory_model::memory_order_relaxed) ) {
1745 m_stat.onDamageAfterRightRotation();
1749 // try to fix the parent height while we've still got the lock
1750 return fix_height_locked( pParent );
1753 node_type * rotate_left_locked( node_type * pParent, node_type * pNode, int hL, node_type * pRight, node_type * pRLeft, int hRL, int hRR )
1755 version_type nodeVersion = pNode->version( memory_model::memory_order_acquire );
1756 node_type * pParentLeft = child( pParent, left_child );
1758 begin_change( pNode, nodeVersion );
1760 // fix up pNode links, careful to be compatible with concurrent traversal for all but pNode
1761 pNode->m_pRight.store( pRLeft, memory_model::memory_order_relaxed );
1762 if ( pRLeft != nullptr )
1763 pRLeft->parent( pNode, memory_model::memory_order_relaxed );
1765 atomics::atomic_thread_fence( memory_model::memory_order_release );
1767 pRight->m_pLeft.store( pNode, memory_model::memory_order_relaxed );
1768 pNode->parent( pRight, memory_model::memory_order_relaxed );
1770 atomics::atomic_thread_fence( memory_model::memory_order_release );
1772 if ( pParentLeft == pNode )
1773 pParent->m_pLeft.store( pRight, memory_model::memory_order_relaxed );
1775 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1776 pParent->m_pRight.store( pRight, memory_model::memory_order_relaxed );
1778 pRight->parent( pParent, memory_model::memory_order_relaxed );
1780 atomics::atomic_thread_fence( memory_model::memory_order_release );
1783 int hNode = 1 + std::max( hL, hRL );
1784 set_height( pNode, hNode );
1785 set_height( pRight, 1 + std::max( hNode, hRR ));
1787 end_change( pNode, nodeVersion );
1788 m_stat.onRotateLeft();
1790 int nodeBalance = hRL - hL;
1791 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1792 m_stat.onRotateAfterLeftRotation();
1796 if ( (pRLeft == nullptr || hL == 0) && !pNode->is_valued(memory_model::memory_order_relaxed) ) {
1797 m_stat.onRemoveAfterLeftRotation();
1801 int rightBalance = hRR - hNode;
1802 if ( rightBalance < -1 || rightBalance > 1 ) {
1803 m_stat.onRotateAfterLeftRotation();
1807 if ( hRR == 0 && !pRight->is_valued(memory_model::memory_order_relaxed) ) {
1808 m_stat.onDamageAfterLeftRotation();
1812 return fix_height_locked( pParent );
1815 node_type * rotate_right_over_left_locked( node_type * pParent, node_type * pNode, node_type * pLeft, int hR, int hLL, node_type * pLRight, int hLRL )
1817 version_type nodeVersion = pNode->version( memory_model::memory_order_acquire );
1818 version_type leftVersion = pLeft->version( memory_model::memory_order_acquire );
1820 node_type * pPL = child( pParent, left_child );
1821 node_type * pLRL = child( pLRight, left_child );
1822 node_type * pLRR = child( pLRight, right_child );
1823 int hLRR = height_null( pLRR );
1825 begin_change( pNode, nodeVersion );
1826 begin_change( pLeft, leftVersion );
1828 // fix up pNode links, careful about the order!
1829 pNode->m_pLeft.store( pLRR, memory_model::memory_order_relaxed );
1830 if ( pLRR != nullptr )
1831 pLRR->parent( pNode, memory_model::memory_order_relaxed );
1832 atomics::atomic_thread_fence( memory_model::memory_order_release );
1834 pLeft->m_pRight.store( pLRL, memory_model::memory_order_relaxed );
1835 if ( pLRL != nullptr )
1836 pLRL->parent( pLeft, memory_model::memory_order_relaxed );
1837 atomics::atomic_thread_fence( memory_model::memory_order_release );
1839 pLRight->m_pLeft.store( pLeft, memory_model::memory_order_relaxed );
1840 pLeft->parent( pLRight, memory_model::memory_order_relaxed );
1841 atomics::atomic_thread_fence( memory_model::memory_order_release );
1843 pLRight->m_pRight.store( pNode, memory_model::memory_order_relaxed );
1844 pNode->parent( pLRight, memory_model::memory_order_relaxed );
1845 atomics::atomic_thread_fence( memory_model::memory_order_release );
1848 pParent->m_pLeft.store( pLRight, memory_model::memory_order_relaxed );
1850 assert( child( pParent, right_child ) == pNode );
1851 pParent->m_pRight.store( pLRight, memory_model::memory_order_relaxed );
1853 pLRight->parent( pParent, memory_model::memory_order_relaxed );
1854 atomics::atomic_thread_fence( memory_model::memory_order_release );
1857 int hNode = 1 + std::max( hLRR, hR );
1858 set_height( pNode, hNode );
1859 int hLeft = 1 + std::max( hLL, hLRL );
1860 set_height( pLeft, hLeft );
1861 set_height( pLRight, 1 + std::max( hLeft, hNode ));
1863 end_change( pNode, nodeVersion );
1864 end_change( pLeft, leftVersion );
1865 m_stat.onRotateRightOverLeft();
1867 // caller should have performed only a single rotation if pLeft was going
1868 // to end up damaged
1869 assert( hLL - hLRL <= 1 && hLRL - hLL <= 1 );
1870 assert( !((hLL == 0 || pLRL == nullptr) && !pLeft->is_valued( memory_model::memory_order_relaxed )));
1872 // We have damaged pParent, pLR (now parent.child), and pNode (now
1873 // parent.child.right). pNode is the deepest. Perform as many fixes as we
1874 // can with the locks we've got.
1876 // We've already fixed the height for pNode, but it might still be outside
1877 // our allowable balance range. In that case a simple fix_height_locked()
1879 int nodeBalance = hLRR - hR;
1880 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1881 // we need another rotation at pNode
1882 m_stat.onRotateAfterRLRotation();
1886 // pNode might also be damaged by being an unnecessary routing node
1887 if ( (pLRR == nullptr || hR == 0) && !pNode->is_valued( memory_model::memory_order_relaxed )) {
1888 // repair involves splicing out pNode and maybe more rotations
1889 m_stat.onRemoveAfterRLRotation();
1893 // we've already fixed the height at pLRight, do we need a rotation here?
1894 int balanceLR = hLeft - hNode;
1895 if ( balanceLR < -1 || balanceLR > 1 ) {
1896 m_stat.onRotateAfterRLRotation();
1900 // try to fix the parent height while we've still got the lock
1901 return fix_height_locked( pParent );
1904 node_type * rotate_left_over_right_locked( node_type * pParent, node_type * pNode, int hL, node_type * pRight, node_type * pRLeft, int hRR, int hRLR )
1906 version_type nodeVersion = pNode->version( memory_model::memory_order_acquire );
1907 version_type rightVersion = pRight->version( memory_model::memory_order_acquire );
1909 node_type * pPL = child( pParent, left_child );
1910 node_type * pRLL = child( pRLeft, left_child );
1911 node_type * pRLR = child( pRLeft, right_child );
1912 int hRLL = height_null( pRLL );
1914 begin_change( pNode, nodeVersion );
1915 begin_change( pRight, rightVersion );
1917 // fix up pNode links, careful about the order!
1918 pNode->m_pRight.store( pRLL, memory_model::memory_order_relaxed );
1919 if ( pRLL != nullptr )
1920 pRLL->parent( pNode, memory_model::memory_order_relaxed );
1921 atomics::atomic_thread_fence( memory_model::memory_order_release );
1923 pRight->m_pLeft.store( pRLR, memory_model::memory_order_relaxed );
1924 if ( pRLR != nullptr )
1925 pRLR->parent( pRight, memory_model::memory_order_relaxed );
1926 atomics::atomic_thread_fence( memory_model::memory_order_release );
1928 pRLeft->m_pRight.store( pRight, memory_model::memory_order_relaxed );
1929 pRight->parent( pRLeft, memory_model::memory_order_relaxed );
1930 atomics::atomic_thread_fence( memory_model::memory_order_release );
1932 pRLeft->m_pLeft.store( pNode, memory_model::memory_order_relaxed );
1933 pNode->parent( pRLeft, memory_model::memory_order_relaxed );
1934 atomics::atomic_thread_fence( memory_model::memory_order_release );
1937 pParent->m_pLeft.store( pRLeft, memory_model::memory_order_relaxed );
1939 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1940 pParent->m_pRight.store( pRLeft, memory_model::memory_order_relaxed );
1942 pRLeft->parent( pParent, memory_model::memory_order_relaxed );
1943 atomics::atomic_thread_fence( memory_model::memory_order_release );
1946 int hNode = 1 + std::max( hL, hRLL );
1947 set_height( pNode, hNode );
1948 int hRight = 1 + std::max( hRLR, hRR );
1949 set_height( pRight, hRight );
1950 set_height( pRLeft, 1 + std::max( hNode, hRight ));
1952 end_change( pNode, nodeVersion );
1953 end_change( pRight, rightVersion );
1954 m_stat.onRotateLeftOverRight();
1956 assert( hRR - hRLR <= 1 && hRLR - hRR <= 1 );
1958 int nodeBalance = hRLL - hL;
1959 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1960 m_stat.onRotateAfterLRRotation();
1964 if ( (pRLL == nullptr || hL == 0) && !pNode->is_valued(memory_model::memory_order_relaxed) ) {
1965 m_stat.onRemoveAfterLRRotation();
1969 int balRL = hRight - hNode;
1970 if ( balRL < -1 || balRL > 1 ) {
1971 m_stat.onRotateAfterLRRotation();
1975 return fix_height_locked( pParent );
1980 }} // namespace cds::container
1982 #endif // #ifndef CDSLIB_CONTAINER_IMPL_BRONSON_AVLTREE_MAP_RCU_H