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 return try_update_node( nFlags, funcUpdate, pNode, nVersion, disp );
1094 node_type * pChild = child( pNode, nCmp );
1095 if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
1096 return update_flags::retry;
1098 if ( pChild == nullptr ) {
1100 if ( nFlags & update_flags::allow_insert )
1101 result = try_insert_node( key, funcUpdate, pNode, nCmp, nVersion, disp );
1103 result = update_flags::failed;
1107 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1108 if ( nChildVersion & node_type::shrinking ) {
1109 m_stat.onUpdateWaitShrinking();
1110 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1112 result = update_flags::retry;
1114 else if ( pChild == child( pNode, nCmp )) {
1115 // this second read is important, because it is protected by nChildVersion
1117 // validate the read that our caller took to get to node
1118 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1119 return update_flags::retry;
1121 // At this point we know that the traversal our parent took to get to node is still valid.
1122 // The recursive implementation will validate the traversal from node to
1123 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1124 // This means that we are no longer vulnerable to node shrinks, and we don't need
1125 // to validate node version any more.
1126 result = try_update( key, cmp, nFlags, funcUpdate, pChild, nChildVersion, disp );
1129 result = update_flags::retry;
1132 if ( result == update_flags::retry ) {
1133 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1134 return update_flags::retry;
1135 m_stat.onUpdateRetry();
1142 template <typename K, typename Compare, typename Func>
1143 int try_remove( K const& key, Compare cmp, Func func, node_type * pParent, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1145 assert( gc::is_locked() );
1146 assert( nVersion != node_type::unlinked );
1148 int nCmp = cmp( key, pNode->m_key );
1150 return try_remove_node( pParent, pNode, nVersion, func, disp );
1155 node_type * pChild = child( pNode, nCmp );
1156 if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
1157 return update_flags::retry;
1159 if ( pChild == nullptr )
1160 return update_flags::failed;
1163 result = update_flags::retry;
1164 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1165 if ( nChildVersion & node_type::shrinking ) {
1166 m_stat.onRemoveWaitShrinking();
1167 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1169 result = update_flags::retry;
1171 else if ( pChild == child( pNode, nCmp )) {
1172 // this second read is important, because it is protected by nChildVersion
1174 // validate the read that our caller took to get to node
1175 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1176 return update_flags::retry;
1178 // At this point we know that the traversal our parent took to get to node is still valid.
1179 // The recursive implementation will validate the traversal from node to
1180 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1181 // This means that we are no longer vulnerable to node shrinks, and we don't need
1182 // to validate node version any more.
1183 result = try_remove( key, cmp, func, pNode, pChild, nChildVersion, disp );
1186 result = update_flags::retry;
1189 if ( result == update_flags::retry ) {
1190 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1191 return update_flags::retry;
1192 m_stat.onRemoveRetry();
1199 template <typename Func>
1200 int try_extract_minmax( int nDir, Func func, node_type * pParent, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1202 assert( gc::is_locked() );
1203 assert( nVersion != node_type::unlinked );
1207 node_type * pChild = child( pNode, nDir );
1208 if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
1209 return update_flags::retry;
1211 if ( pChild == nullptr ) {
1213 return try_remove_node( pParent, pNode, nVersion, func, disp );
1216 //result = update_flags::retry;
1217 version_type nChildVersion = pChild->version( memory_model::memory_order_acquire );
1218 if ( nChildVersion & node_type::shrinking ) {
1219 m_stat.onRemoveWaitShrinking();
1220 pChild->template wait_until_shrink_completed<back_off>( memory_model::memory_order_relaxed );
1222 result = update_flags::retry;
1224 else if ( pChild == child( pNode, nDir )) {
1225 // this second read is important, because it is protected by nChildVersion
1227 // validate the read that our caller took to get to node
1228 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1229 return update_flags::retry;
1231 // At this point we know that the traversal our parent took to get to node is still valid.
1232 // The recursive implementation will validate the traversal from node to
1233 // child, so just prior to the node nVersion validation both traversals were definitely okay.
1234 // This means that we are no longer vulnerable to node shrinks, and we don't need
1235 // to validate node version any more.
1236 result = try_extract_minmax( nDir, func, pNode, pChild, nChildVersion, disp );
1239 result = update_flags::retry;
1242 if ( result == update_flags::retry ) {
1243 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion )
1244 return update_flags::retry;
1245 m_stat.onRemoveRetry();
1252 template <typename K, typename Func>
1253 int try_insert_node( K const& key, Func funcUpdate, node_type * pNode, int nDir, version_type nVersion, rcu_disposer& disp )
1257 auto fnCreateNode = [&funcUpdate]( node_type * pNew ) {
1258 mapped_type pVal = funcUpdate( pNew );
1259 assert( pVal != nullptr );
1260 pNew->m_pValue.store( pVal, memory_model::memory_order_relaxed );
1263 if ( c_bRelaxedInsert ) {
1264 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion
1265 || child( pNode, nDir ) != nullptr )
1267 m_stat.onInsertRetry();
1268 return update_flags::retry;
1271 fnCreateNode( pNew = alloc_node( key, 1, 0, pNode, nullptr, nullptr ));
1274 node_type * pDamaged;
1276 assert( pNode != nullptr );
1277 node_scoped_lock l( m_Monitor, *pNode );
1279 if ( pNode->version( memory_model::memory_order_acquire ) != nVersion
1280 || child( pNode, nDir ) != nullptr )
1282 if ( c_bRelaxedInsert ) {
1283 mapped_type pVal = pNew->m_pValue.load( memory_model::memory_order_relaxed );
1284 pNew->m_pValue.store( nullptr, memory_model::memory_order_relaxed );
1287 m_stat.onRelaxedInsertFailed();
1290 m_stat.onInsertRetry();
1291 return update_flags::retry;
1294 if ( !c_bRelaxedInsert )
1295 fnCreateNode( pNew = alloc_node( key, 1, 0, pNode, nullptr, nullptr ));
1297 pNode->child( pNew, nDir, memory_model::memory_order_relaxed );
1298 pDamaged = fix_height_locked( pNode );
1302 m_stat.onInsertSuccess();
1305 fix_height_and_rebalance( pDamaged, disp );
1306 m_stat.onInsertRebalanceRequired();
1309 return update_flags::result_inserted;
1312 template <typename Func>
1313 int try_update_node( int nFlags, Func funcUpdate, node_type * pNode, version_type nVersion, rcu_disposer& disp )
1316 assert( pNode != nullptr );
1318 node_scoped_lock l( m_Monitor, *pNode );
1320 if ( pNode->version(memory_model::memory_order_acquire) != nVersion )
1321 return update_flags::retry;
1323 if ( pNode->is_unlinked( memory_model::memory_order_relaxed )) {
1324 m_stat.onUpdateUnlinked();
1325 return update_flags::retry;
1328 if ( pNode->is_valued( memory_model::memory_order_relaxed ) && !(nFlags & update_flags::allow_update) ) {
1329 m_stat.onInsertFailed();
1330 return update_flags::failed;
1334 pOld = pNode->value( memory_model::memory_order_relaxed );
1335 mapped_type pVal = funcUpdate( pNode );
1339 assert( pVal != nullptr );
1340 pNode->m_pValue.store( pVal, memory_model::memory_order_relaxed );
1345 disp.dispose_value(pOld);
1346 m_stat.onDisposeValue();
1349 m_stat.onUpdateSuccess();
1350 return update_flags::result_updated;
1353 template <typename Func>
1354 int try_remove_node( node_type * pParent, node_type * pNode, version_type nVersion, Func func, rcu_disposer& disp )
1356 assert( pParent != nullptr );
1357 assert( pNode != nullptr );
1359 if ( !pNode->is_valued( atomics::memory_order_relaxed ) )
1360 return update_flags::failed;
1362 if ( child( pNode, left_child ) == nullptr || child( pNode, right_child ) == nullptr ) {
1363 node_type * pDamaged;
1366 node_scoped_lock lp( m_Monitor, *pParent );
1367 if ( pParent->is_unlinked( atomics::memory_order_relaxed ) || parent( pNode ) != pParent )
1368 return update_flags::retry;
1371 node_scoped_lock ln( m_Monitor, *pNode );
1372 pOld = pNode->value( memory_model::memory_order_relaxed );
1373 if ( !( pNode->version( memory_model::memory_order_acquire ) == nVersion
1375 && try_unlink_locked( pParent, pNode, disp )))
1377 return update_flags::retry;
1380 pDamaged = fix_height_locked( pParent );
1384 if ( func( pNode->m_key, pOld, disp )) // calls pOld disposer inside
1385 m_stat.onDisposeValue();
1387 m_stat.onExtractValue();
1390 fix_height_and_rebalance( pDamaged, disp );
1391 m_stat.onRemoveRebalanceRequired();
1393 return update_flags::result_removed;
1396 int result = update_flags::retry;
1399 node_scoped_lock ln( m_Monitor, *pNode );
1400 pOld = pNode->value( atomics::memory_order_relaxed );
1401 if ( pNode->version( atomics::memory_order_acquire ) == nVersion && pOld ) {
1402 pNode->m_pValue.store( nullptr, atomics::memory_order_relaxed );
1403 result = update_flags::result_removed;
1407 if ( result == update_flags::result_removed ) {
1409 if ( func( pNode->m_key, pOld, disp )) // calls pOld disposer inside
1410 m_stat.onDisposeValue();
1412 m_stat.onExtractValue();
1419 bool try_unlink_locked( node_type * pParent, node_type * pNode, rcu_disposer& disp )
1421 // pParent and pNode must be locked
1422 assert( !pParent->is_unlinked(memory_model::memory_order_relaxed) );
1424 node_type * pParentLeft = child( pParent, left_child );
1425 node_type * pParentRight = child( pParent, right_child );
1426 if ( pNode != pParentLeft && pNode != pParentRight ) {
1427 // node is no longer a child of parent
1431 assert( !pNode->is_unlinked( memory_model::memory_order_relaxed ) );
1432 assert( pParent == parent( pNode ));
1434 node_type * pLeft = child( pNode, left_child );
1435 node_type * pRight = child( pNode, right_child );
1436 if ( pLeft != nullptr && pRight != nullptr ) {
1437 // splicing is no longer possible
1440 node_type * pSplice = pLeft ? pLeft : pRight;
1442 if ( pParentLeft == pNode )
1443 pParent->m_pLeft.store( pSplice, memory_model::memory_order_relaxed );
1445 pParent->m_pRight.store( pSplice, memory_model::memory_order_relaxed );
1448 pSplice->parent( pParent, memory_model::memory_order_relaxed );
1450 // Mark the node as unlinked
1451 pNode->version( node_type::unlinked, memory_model::memory_order_release );
1453 // The value will be disposed by calling function
1454 pNode->m_pValue.store( nullptr, memory_model::memory_order_relaxed );
1456 disp.dispose( pNode );
1457 m_stat.onDisposeNode();
1464 private: // rotations
1466 int estimate_node_condition( node_type * pNode )
1468 node_type * pLeft = child( pNode, left_child );
1469 node_type * pRight = child( pNode, right_child );
1471 if ( (pLeft == nullptr || pRight == nullptr) && !pNode->is_valued( memory_model::memory_order_relaxed ))
1472 return unlink_required;
1474 int h = height( pNode );
1475 int hL = height_null( pLeft );
1476 int hR = height_null( pRight );
1478 int hNew = 1 + std::max( hL, hR );
1479 int nBalance = hL - hR;
1481 if ( nBalance < -1 || nBalance > 1 )
1482 return rebalance_required;
1484 return h != hNew ? hNew : nothing_required;
1487 node_type * fix_height( node_type * pNode )
1489 assert( pNode != nullptr );
1490 node_scoped_lock l( m_Monitor, *pNode );
1491 return fix_height_locked( pNode );
1494 node_type * fix_height_locked( node_type * pNode )
1496 // pNode must be locked!!!
1497 int h = estimate_node_condition( pNode );
1499 case rebalance_required:
1500 case unlink_required:
1502 case nothing_required:
1505 set_height( pNode, h );
1506 return parent( pNode );
1510 void fix_height_and_rebalance( node_type * pNode, rcu_disposer& disp )
1512 while ( pNode && parent( pNode )) {
1513 int nCond = estimate_node_condition( pNode );
1514 if ( nCond == nothing_required || pNode->is_unlinked( memory_model::memory_order_relaxed ) )
1517 if ( nCond != unlink_required && nCond != rebalance_required )
1518 pNode = fix_height( pNode );
1520 node_type * pParent = parent( pNode );
1521 assert( pParent != nullptr );
1523 node_scoped_lock lp( m_Monitor, *pParent );
1524 if ( !pParent->is_unlinked( memory_model::memory_order_relaxed ) && parent( pNode ) == pParent ) {
1525 node_scoped_lock ln( m_Monitor, *pNode );
1526 pNode = rebalance_locked( pParent, pNode, disp );
1533 node_type * rebalance_locked( node_type * pParent, node_type * pNode, rcu_disposer& disp )
1535 // pParent and pNode should be locked.
1536 // Returns a damaged node, or nullptr if no more rebalancing is necessary
1537 assert( parent( pNode ) == pParent );
1539 node_type * pLeft = child( pNode, left_child );
1540 node_type * pRight = child( pNode, right_child );
1542 if ( (pLeft == nullptr || pRight == nullptr) && !pNode->is_valued( memory_model::memory_order_relaxed )) {
1543 if ( try_unlink_locked( pParent, pNode, disp ))
1544 return fix_height_locked( pParent );
1546 // retry needed for pNode
1551 assert( child( pParent, left_child ) == pNode || child( pParent, right_child ) == pNode );
1553 int h = height( pNode );
1554 int hL = height_null( pLeft );
1555 int hR = height_null( pRight );
1556 int hNew = 1 + std::max( hL, hR );
1557 int balance = hL - hR;
1560 return rebalance_to_right_locked( pParent, pNode, pLeft, hR );
1561 else if ( balance < -1 )
1562 return rebalance_to_left_locked( pParent, pNode, pRight, hL );
1563 else if ( hNew != h ) {
1564 set_height( pNode, hNew );
1566 // pParent is already locked
1567 return fix_height_locked( pParent );
1573 node_type * rebalance_to_right_locked( node_type * pParent, node_type * pNode, node_type * pLeft, int hR )
1575 assert( parent( pNode ) == pParent );
1576 assert( child( pParent, left_child ) == pNode || child( pParent, right_child ) == pNode );
1578 // pParent and pNode is locked yet
1579 // pNode->pLeft is too large, we will rotate-right.
1580 // If pLeft->pRight is taller than pLeft->pLeft, then we will first rotate-left pLeft.
1583 assert( pLeft != nullptr );
1584 node_scoped_lock l( m_Monitor, *pLeft );
1585 if ( pNode->m_pLeft.load( memory_model::memory_order_relaxed ) != pLeft )
1586 return pNode; // retry for pNode
1588 int hL = height( pLeft );
1590 return pNode; // retry
1592 node_type * pLRight = child( pLeft, right_child );
1593 int hLR = height_null( pLRight );
1594 node_type * pLLeft = child( pLeft, left_child );
1595 int hLL = height_null( pLLeft );
1599 return rotate_right_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLR );
1602 assert( pLRight != nullptr );
1604 node_scoped_lock lr( m_Monitor, *pLRight );
1605 if ( pLeft->m_pRight.load( memory_model::memory_order_relaxed ) != pLRight )
1606 return pNode; // retry
1608 hLR = height( pLRight );
1610 return rotate_right_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLR );
1612 int hLRL = height_null( child( pLRight, left_child ));
1613 int balance = hLL - hLRL;
1614 if ( balance >= -1 && balance <= 1 && !((hLL == 0 || hLRL == 0) && !pLeft->is_valued(memory_model::memory_order_relaxed))) {
1615 // nParent.child.left won't be damaged after a double rotation
1616 return rotate_right_over_left_locked( pParent, pNode, pLeft, hR, hLL, pLRight, hLRL );
1620 // focus on pLeft, if necessary pNode will be balanced later
1621 return rebalance_to_left_locked( pNode, pLeft, pLRight, hLL );
1626 node_type * rebalance_to_left_locked( node_type * pParent, node_type * pNode, node_type * pRight, int hL )
1628 assert( parent( pNode ) == pParent );
1629 assert( child( pParent, left_child ) == pNode || child( pParent, right_child ) == pNode );
1631 // pParent and pNode is locked yet
1633 assert( pRight != nullptr );
1634 node_scoped_lock l( m_Monitor, *pRight );
1635 if ( pNode->m_pRight.load( memory_model::memory_order_relaxed ) != pRight )
1636 return pNode; // retry for pNode
1638 int hR = height( pRight );
1639 if ( hL - hR >= -1 )
1640 return pNode; // retry
1642 node_type * pRLeft = child( pRight, left_child );
1643 int hRL = height_null( pRLeft );
1644 node_type * pRRight = child( pRight, right_child );
1645 int hRR = height_null( pRRight );
1647 return rotate_left_locked( pParent, pNode, hL, pRight, pRLeft, hRL, hRR );
1650 assert( pRLeft != nullptr );
1651 node_scoped_lock lrl( m_Monitor, *pRLeft );
1652 if ( pRight->m_pLeft.load( memory_model::memory_order_relaxed ) != pRLeft )
1653 return pNode; // retry
1655 hRL = height( pRLeft );
1657 return rotate_left_locked( pParent, pNode, hL, pRight, pRLeft, hRL, hRR );
1659 node_type * pRLRight = child( pRLeft, right_child );
1660 int hRLR = height_null( pRLRight );
1661 int balance = hRR - hRLR;
1662 if ( balance >= -1 && balance <= 1 && !((hRR == 0 || hRLR == 0) && !pRight->is_valued( memory_model::memory_order_relaxed )))
1663 return rotate_left_over_right_locked( pParent, pNode, hL, pRight, pRLeft, hRR, hRLR );
1665 return rebalance_to_right_locked( pNode, pRight, pRLeft, hRR );
1669 static void begin_change( node_type * pNode, version_type version )
1671 assert(pNode->version(memory_model::memory_order_acquire) == version );
1672 assert( (version & node_type::shrinking) == 0 );
1673 pNode->version( version | node_type::shrinking, memory_model::memory_order_release );
1675 static void end_change( node_type * pNode, version_type version )
1677 // Clear shrinking and unlinked flags and increment version
1678 pNode->version( (version | node_type::version_flags) + 1, memory_model::memory_order_release );
1681 node_type * rotate_right_locked( node_type * pParent, node_type * pNode, node_type * pLeft, int hR, int hLL, node_type * pLRight, int hLR )
1683 version_type nodeVersion = pNode->version( memory_model::memory_order_acquire );
1684 node_type * pParentLeft = child( pParent, left_child );
1686 begin_change( pNode, nodeVersion );
1688 pNode->m_pLeft.store( pLRight, memory_model::memory_order_relaxed );
1689 if ( pLRight != nullptr )
1690 pLRight->parent( pNode, memory_model::memory_order_relaxed );
1692 atomics::atomic_thread_fence( memory_model::memory_order_release );
1694 pLeft->m_pRight.store( pNode, memory_model::memory_order_relaxed );
1695 pNode->parent( pLeft, memory_model::memory_order_relaxed );
1697 atomics::atomic_thread_fence( memory_model::memory_order_release );
1699 if ( pParentLeft == pNode )
1700 pParent->m_pLeft.store( pLeft, memory_model::memory_order_relaxed );
1702 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1703 pParent->m_pRight.store( pLeft, memory_model::memory_order_relaxed );
1705 pLeft->parent( pParent, memory_model::memory_order_relaxed );
1707 atomics::atomic_thread_fence( memory_model::memory_order_release );
1709 // fix up heights links
1710 int hNode = 1 + std::max( hLR, hR );
1711 set_height( pNode, hNode );
1712 set_height( pLeft, 1 + std::max( hLL, hNode ));
1714 end_change( pNode, nodeVersion );
1715 m_stat.onRotateRight();
1717 // We have damaged pParent, pNode (now parent.child.right), and pLeft (now
1718 // parent.child). pNode is the deepest. Perform as many fixes as we can
1719 // with the locks we've got.
1721 // We've already fixed the height for pNode, but it might still be outside
1722 // our allowable balance range. In that case a simple fix_height_locked()
1724 int nodeBalance = hLR - hR;
1725 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1726 // we need another rotation at pNode
1727 m_stat.onRotateAfterRightRotation();
1731 // we've fixed balance and height damage for pNode, now handle
1732 // extra-routing node damage
1733 if ( (pLRight == nullptr || hR == 0) && !pNode->is_valued(memory_model::memory_order_relaxed)) {
1734 // we need to remove pNode and then repair
1735 m_stat.onRemoveAfterRightRotation();
1739 // we've already fixed the height at pLeft, do we need a rotation here?
1740 int leftBalance = hLL - hNode;
1741 if ( leftBalance < -1 || leftBalance > 1 ) {
1742 m_stat.onRotateAfterRightRotation();
1746 // pLeft might also have routing node damage (if pLeft.left was null)
1747 if ( hLL == 0 && !pLeft->is_valued(memory_model::memory_order_relaxed) ) {
1748 m_stat.onDamageAfterRightRotation();
1752 // try to fix the parent height while we've still got the lock
1753 return fix_height_locked( pParent );
1756 node_type * rotate_left_locked( node_type * pParent, node_type * pNode, int hL, node_type * pRight, node_type * pRLeft, int hRL, int hRR )
1758 version_type nodeVersion = pNode->version( memory_model::memory_order_acquire );
1759 node_type * pParentLeft = child( pParent, left_child );
1761 begin_change( pNode, nodeVersion );
1763 // fix up pNode links, careful to be compatible with concurrent traversal for all but pNode
1764 pNode->m_pRight.store( pRLeft, memory_model::memory_order_relaxed );
1765 if ( pRLeft != nullptr )
1766 pRLeft->parent( pNode, memory_model::memory_order_relaxed );
1768 atomics::atomic_thread_fence( memory_model::memory_order_release );
1770 pRight->m_pLeft.store( pNode, memory_model::memory_order_relaxed );
1771 pNode->parent( pRight, memory_model::memory_order_relaxed );
1773 atomics::atomic_thread_fence( memory_model::memory_order_release );
1775 if ( pParentLeft == pNode )
1776 pParent->m_pLeft.store( pRight, memory_model::memory_order_relaxed );
1778 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1779 pParent->m_pRight.store( pRight, memory_model::memory_order_relaxed );
1781 pRight->parent( pParent, memory_model::memory_order_relaxed );
1783 atomics::atomic_thread_fence( memory_model::memory_order_release );
1786 int hNode = 1 + std::max( hL, hRL );
1787 set_height( pNode, hNode );
1788 set_height( pRight, 1 + std::max( hNode, hRR ));
1790 end_change( pNode, nodeVersion );
1791 m_stat.onRotateLeft();
1793 int nodeBalance = hRL - hL;
1794 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1795 m_stat.onRotateAfterLeftRotation();
1799 if ( (pRLeft == nullptr || hL == 0) && !pNode->is_valued(memory_model::memory_order_relaxed) ) {
1800 m_stat.onRemoveAfterLeftRotation();
1804 int rightBalance = hRR - hNode;
1805 if ( rightBalance < -1 || rightBalance > 1 ) {
1806 m_stat.onRotateAfterLeftRotation();
1810 if ( hRR == 0 && !pRight->is_valued(memory_model::memory_order_relaxed) ) {
1811 m_stat.onDamageAfterLeftRotation();
1815 return fix_height_locked( pParent );
1818 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 )
1820 version_type nodeVersion = pNode->version( memory_model::memory_order_acquire );
1821 version_type leftVersion = pLeft->version( memory_model::memory_order_acquire );
1823 node_type * pPL = child( pParent, left_child );
1824 node_type * pLRL = child( pLRight, left_child );
1825 node_type * pLRR = child( pLRight, right_child );
1826 int hLRR = height_null( pLRR );
1828 begin_change( pNode, nodeVersion );
1829 begin_change( pLeft, leftVersion );
1831 // fix up pNode links, careful about the order!
1832 pNode->m_pLeft.store( pLRR, memory_model::memory_order_relaxed );
1833 if ( pLRR != nullptr )
1834 pLRR->parent( pNode, memory_model::memory_order_relaxed );
1835 atomics::atomic_thread_fence( memory_model::memory_order_release );
1837 pLeft->m_pRight.store( pLRL, memory_model::memory_order_relaxed );
1838 if ( pLRL != nullptr )
1839 pLRL->parent( pLeft, memory_model::memory_order_relaxed );
1840 atomics::atomic_thread_fence( memory_model::memory_order_release );
1842 pLRight->m_pLeft.store( pLeft, memory_model::memory_order_relaxed );
1843 pLeft->parent( pLRight, memory_model::memory_order_relaxed );
1844 atomics::atomic_thread_fence( memory_model::memory_order_release );
1846 pLRight->m_pRight.store( pNode, memory_model::memory_order_relaxed );
1847 pNode->parent( pLRight, memory_model::memory_order_relaxed );
1848 atomics::atomic_thread_fence( memory_model::memory_order_release );
1851 pParent->m_pLeft.store( pLRight, memory_model::memory_order_relaxed );
1853 assert( child( pParent, right_child ) == pNode );
1854 pParent->m_pRight.store( pLRight, memory_model::memory_order_relaxed );
1856 pLRight->parent( pParent, memory_model::memory_order_relaxed );
1857 atomics::atomic_thread_fence( memory_model::memory_order_release );
1860 int hNode = 1 + std::max( hLRR, hR );
1861 set_height( pNode, hNode );
1862 int hLeft = 1 + std::max( hLL, hLRL );
1863 set_height( pLeft, hLeft );
1864 set_height( pLRight, 1 + std::max( hLeft, hNode ));
1866 end_change( pNode, nodeVersion );
1867 end_change( pLeft, leftVersion );
1868 m_stat.onRotateRightOverLeft();
1870 // caller should have performed only a single rotation if pLeft was going
1871 // to end up damaged
1872 assert( hLL - hLRL <= 1 && hLRL - hLL <= 1 );
1873 assert( !((hLL == 0 || pLRL == nullptr) && !pLeft->is_valued( memory_model::memory_order_relaxed )));
1875 // We have damaged pParent, pLR (now parent.child), and pNode (now
1876 // parent.child.right). pNode is the deepest. Perform as many fixes as we
1877 // can with the locks we've got.
1879 // We've already fixed the height for pNode, but it might still be outside
1880 // our allowable balance range. In that case a simple fix_height_locked()
1882 int nodeBalance = hLRR - hR;
1883 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1884 // we need another rotation at pNode
1885 m_stat.onRotateAfterRLRotation();
1889 // pNode might also be damaged by being an unnecessary routing node
1890 if ( (pLRR == nullptr || hR == 0) && !pNode->is_valued( memory_model::memory_order_relaxed )) {
1891 // repair involves splicing out pNode and maybe more rotations
1892 m_stat.onRemoveAfterRLRotation();
1896 // we've already fixed the height at pLRight, do we need a rotation here?
1897 int balanceLR = hLeft - hNode;
1898 if ( balanceLR < -1 || balanceLR > 1 ) {
1899 m_stat.onRotateAfterRLRotation();
1903 // try to fix the parent height while we've still got the lock
1904 return fix_height_locked( pParent );
1907 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 )
1909 version_type nodeVersion = pNode->version( memory_model::memory_order_acquire );
1910 version_type rightVersion = pRight->version( memory_model::memory_order_acquire );
1912 node_type * pPL = child( pParent, left_child );
1913 node_type * pRLL = child( pRLeft, left_child );
1914 node_type * pRLR = child( pRLeft, right_child );
1915 int hRLL = height_null( pRLL );
1917 begin_change( pNode, nodeVersion );
1918 begin_change( pRight, rightVersion );
1920 // fix up pNode links, careful about the order!
1921 pNode->m_pRight.store( pRLL, memory_model::memory_order_relaxed );
1922 if ( pRLL != nullptr )
1923 pRLL->parent( pNode, memory_model::memory_order_relaxed );
1924 atomics::atomic_thread_fence( memory_model::memory_order_release );
1926 pRight->m_pLeft.store( pRLR, memory_model::memory_order_relaxed );
1927 if ( pRLR != nullptr )
1928 pRLR->parent( pRight, memory_model::memory_order_relaxed );
1929 atomics::atomic_thread_fence( memory_model::memory_order_release );
1931 pRLeft->m_pRight.store( pRight, memory_model::memory_order_relaxed );
1932 pRight->parent( pRLeft, memory_model::memory_order_relaxed );
1933 atomics::atomic_thread_fence( memory_model::memory_order_release );
1935 pRLeft->m_pLeft.store( pNode, memory_model::memory_order_relaxed );
1936 pNode->parent( pRLeft, memory_model::memory_order_relaxed );
1937 atomics::atomic_thread_fence( memory_model::memory_order_release );
1940 pParent->m_pLeft.store( pRLeft, memory_model::memory_order_relaxed );
1942 assert( pParent->m_pRight.load( memory_model::memory_order_relaxed ) == pNode );
1943 pParent->m_pRight.store( pRLeft, memory_model::memory_order_relaxed );
1945 pRLeft->parent( pParent, memory_model::memory_order_relaxed );
1946 atomics::atomic_thread_fence( memory_model::memory_order_release );
1949 int hNode = 1 + std::max( hL, hRLL );
1950 set_height( pNode, hNode );
1951 int hRight = 1 + std::max( hRLR, hRR );
1952 set_height( pRight, hRight );
1953 set_height( pRLeft, 1 + std::max( hNode, hRight ));
1955 end_change( pNode, nodeVersion );
1956 end_change( pRight, rightVersion );
1957 m_stat.onRotateLeftOverRight();
1959 assert( hRR - hRLR <= 1 && hRLR - hRR <= 1 );
1961 int nodeBalance = hRLL - hL;
1962 if ( nodeBalance < -1 || nodeBalance > 1 ) {
1963 m_stat.onRotateAfterLRRotation();
1967 if ( (pRLL == nullptr || hL == 0) && !pNode->is_valued(memory_model::memory_order_relaxed) ) {
1968 m_stat.onRemoveAfterLRRotation();
1972 int balRL = hRight - hNode;
1973 if ( balRL < -1 || balRL > 1 ) {
1974 m_stat.onRotateAfterLRRotation();
1978 return fix_height_locked( pParent );
1983 }} // namespace cds::container
1985 #endif // #ifndef CDSLIB_CONTAINER_IMPL_BRONSON_AVLTREE_MAP_RCU_H