2 This file is a part of libcds - Concurrent Data Structures library
4 (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
6 Source code repo: http://github.com/khizmax/libcds/
7 Download: http://sourceforge.net/projects/libcds/files/
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31 #ifndef CDSLIB_INTRUSIVE_MICHAEL_LIST_RCU_H
32 #define CDSLIB_INTRUSIVE_MICHAEL_LIST_RCU_H
34 #include <cds/intrusive/details/michael_list_base.h>
35 #include <cds/urcu/details/check_deadlock.h>
36 #include <cds/details/binary_functor_wrapper.h>
37 #include <cds/details/make_const_type.h>
38 #include <cds/urcu/exempt_ptr.h>
39 #include <cds/urcu/raw_ptr.h>
40 #include <cds/intrusive/details/raw_ptr_disposer.h>
42 namespace cds { namespace intrusive {
45 namespace michael_list {
47 /// Node specialization for uRCU
48 template <class RCU, typename Tag>
49 struct node< cds::urcu::gc< RCU >, Tag >
51 typedef cds::urcu::gc< RCU > gc; ///< Garbage collector
52 typedef Tag tag; ///< tag
54 typedef cds::details::marked_ptr<node, 3> marked_ptr; ///< marked pointer
55 typedef typename gc::template atomic_marked_ptr<marked_ptr> atomic_marked_ptr; ///< atomic marked pointer specific for GC
57 atomic_marked_ptr m_pNext; ///< pointer to the next node in the container
58 node * m_pDelChain; ///< Deleted node chain (local for a thread)
60 CDS_CONSTEXPR node() CDS_NOEXCEPT
62 , m_pDelChain( nullptr )
65 } // namespace michael_list
68 /// Michael's lock-free ordered single-linked list (template specialization for \ref cds_urcu_desc "RCU")
69 /** @ingroup cds_intrusive_list
70 \anchor cds_intrusive_MichaelList_rcu
72 Usually, ordered single-linked list is used as a building block for the hash table implementation.
73 The complexity of searching is <tt>O(N)</tt>.
76 - \p RCU - one of \ref cds_urcu_gc "RCU type"
77 - \p T - type to be stored in the list; the type \p T should be based on (or has a member of type)
78 cds::intrusive::micheal_list::node
79 - \p Traits - type traits. See \p michael_list::traits for explanation. It is possible to declare option-based
80 list with \p cds::intrusive::michael_list::make_traits metafunction,
81 see \ref cds_intrusive_MichaelList_hp "here" for explanations.
84 Before including <tt><cds/intrusive/michael_list_rcu.h></tt> you should include appropriate RCU header file,
85 see \ref cds_urcu_gc "RCU type" for list of existing RCU class and corresponding header files.
86 For example, for \ref cds_urcu_general_buffered_gc "general-purpose buffered RCU" you should include:
88 #include <cds/urcu/general_buffered.h>
89 #include <cds/intrusive/michael_list_rcu.h>
91 // Now, you can declare Michael's list for type Foo and default traits:
92 typedef cds::intrusive::MichaelList<cds::urcu::gc< cds::urcu::general_buffered<> >, Foo > rcu_michael_list;
95 template < typename RCU, typename T,
96 #ifdef CDS_DOXYGEN_INVOKED
97 class Traits = michael_list::traits
102 class MichaelList<cds::urcu::gc<RCU>, T, Traits>
105 typedef T value_type; ///< type of value stored in the list
106 typedef Traits traits; ///< Traits template parameter
108 typedef typename traits::hook hook; ///< hook type
109 typedef typename hook::node_type node_type; ///< node type
111 # ifdef CDS_DOXYGEN_INVOKED
112 typedef implementation_defined key_comparator ; ///< key comparison functor based on opt::compare and opt::less option setter.
114 typedef typename opt::details::make_comparator< value_type, traits >::type key_comparator;
117 typedef typename traits::disposer disposer; ///< disposer used
118 typedef typename get_node_traits< value_type, node_type, hook>::type node_traits ; ///< node traits
119 typedef typename michael_list::get_link_checker< node_type, traits::link_checker >::type link_checker; ///< link checker
121 typedef cds::urcu::gc<RCU> gc; ///< RCU schema
122 typedef typename traits::back_off back_off; ///< back-off strategy
123 typedef typename traits::item_counter item_counter; ///< Item counting policy used
124 typedef typename traits::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
125 typedef typename traits::rcu_check_deadlock rcu_check_deadlock; ///< Deadlock checking policy
126 typedef typename traits::stat stat; ///< Internal statistics
128 typedef typename gc::scoped_lock rcu_lock ; ///< RCU scoped lock
129 static CDS_CONSTEXPR const bool c_bExtractLockExternal = false; ///< Group of \p extract_xxx functions do not require external locking
132 // Rebind traits (split-list support)
133 template <typename... Options>
134 struct rebind_traits {
138 , typename cds::opt::make_options< traits, Options...>::type
143 template <typename Stat>
144 using select_stat_wrapper = michael_list::select_stat_wrapper< Stat >;
148 typedef typename node_type::marked_ptr marked_node_ptr; ///< Marked node pointer
149 typedef typename node_type::atomic_marked_ptr atomic_node_ptr; ///< Atomic node pointer
150 typedef atomic_node_ptr auxiliary_head; ///< Auxiliary head type (for split-list support)
152 atomic_node_ptr m_pHead; ///< Head pointer
153 item_counter m_ItemCounter; ///< Item counter
154 stat m_Stat; ///< Internal statistics
164 typedef cds::urcu::details::check_deadlock_policy< gc, rcu_check_deadlock> check_deadlock_policy;
166 struct clear_and_dispose {
167 void operator()( value_type * p )
169 assert( p != nullptr );
170 clear_links( node_traits::to_node_ptr(p));
175 /// Position pointer for item search
177 atomic_node_ptr * pPrev ; ///< Previous node
178 node_type * pCur ; ///< Current node
179 node_type * pNext ; ///< Next node
181 atomic_node_ptr& refHead;
182 node_type * pDelChain; ///< Head of deleted node chain
184 position( atomic_node_ptr& head )
186 , pDelChain( nullptr )
191 dispose_chain( pDelChain );
197 using exempt_ptr = cds::urcu::exempt_ptr< gc, value_type, value_type, clear_and_dispose, void >; ///< pointer to extracted node
201 struct chain_disposer {
202 void operator()( node_type * pChain ) const
204 dispose_chain( pChain );
207 typedef cds::intrusive::details::raw_ptr_disposer< gc, node_type, chain_disposer> raw_ptr_disposer;
211 /// Result of \p get(), \p get_with() functions - pointer to the node found
212 typedef cds::urcu::raw_ptr< gc, value_type, raw_ptr_disposer > raw_ptr;
216 template <bool IsConst>
219 friend class MichaelList;
220 value_type * m_pNode;
225 node_type * p = node_traits::to_node_ptr( *m_pNode )->m_pNext.load(memory_model::memory_order_relaxed).ptr();
226 m_pNode = p ? node_traits::to_value_ptr( p ) : nullptr;
231 explicit iterator_type( node_type * pNode)
234 m_pNode = node_traits::to_value_ptr( *pNode );
238 explicit iterator_type( atomic_node_ptr const& refNode)
240 node_type * pNode = refNode.load(memory_model::memory_order_relaxed).ptr();
241 m_pNode = pNode ? node_traits::to_value_ptr( *pNode ) : nullptr;
245 typedef typename cds::details::make_const_type<value_type, IsConst>::pointer value_ptr;
246 typedef typename cds::details::make_const_type<value_type, IsConst>::reference value_ref;
252 iterator_type( const iterator_type& src )
253 : m_pNode( src.m_pNode )
256 value_ptr operator ->() const
261 value_ref operator *() const
263 assert( m_pNode != nullptr );
268 iterator_type& operator ++()
275 iterator_type operator ++(int)
277 iterator_type i(*this);
282 iterator_type& operator = (const iterator_type& src)
284 m_pNode = src.m_pNode;
289 bool operator ==(iterator_type<C> const& i ) const
291 return m_pNode == i.m_pNode;
294 bool operator !=(iterator_type<C> const& i ) const
296 return m_pNode != i.m_pNode;
302 ///@name Forward iterators (thread-safe only under RCU lock)
306 You may safely use iterators in multi-threaded environment only under RCU lock.
307 Otherwise, a crash is possible if another thread deletes the item the iterator points to.
309 typedef iterator_type<false> iterator;
311 /// Const forward iterator
312 typedef iterator_type<true> const_iterator;
314 /// Returns a forward iterator addressing the first element in a list
316 For empty list \code begin() == end() \endcode
320 return iterator( m_pHead );
323 /// Returns an iterator that addresses the location succeeding the last element in a list
325 Do not use the value returned by <tt>end</tt> function to access any item.
326 Internally, <tt>end</tt> returning value equals to \p nullptr.
328 The returned value can be used only to control reaching the end of the list.
329 For empty list \code begin() == end() \endcode
336 /// Returns a forward const iterator addressing the first element in a list
337 const_iterator begin() const
339 return const_iterator(m_pHead );
341 /// Returns a forward const iterator addressing the first element in a list
342 const_iterator cbegin() const
344 return const_iterator(m_pHead );
347 /// Returns an const iterator that addresses the location succeeding the last element in a list
348 const_iterator end() const
350 return const_iterator();
352 /// Returns an const iterator that addresses the location succeeding the last element in a list
353 const_iterator cend() const
355 return const_iterator();
360 /// Default constructor initializes empty list
364 static_assert( (std::is_same< gc, typename node_type::gc >::value), "GC and node_type::gc must be the same type" );
368 template <typename Stat, typename = std::enable_if<std::is_same<stat, michael_list::wrapped_stat<Stat>>::value >>
369 explicit MichaelList( Stat& st )
383 The function inserts \p val in the list if the list does not contain
384 an item with key equal to \p val.
386 The function makes RCU lock internally.
388 Returns \p true if \p val is linked into the list, \p false otherwise.
390 bool insert( value_type& val )
392 return insert_at( m_pHead, val );
397 This function is intended for derived non-intrusive containers.
399 The function allows to split new item creating into two part:
400 - create item with key only
401 - insert new item into the list
402 - if inserting is success, calls \p f functor to initialize value-field of \p val.
404 The functor signature is:
406 void func( value_type& val );
408 where \p val is the item inserted. User-defined functor \p f should guarantee that during changing
409 \p val no any other changes could be made on this list's item by concurrent threads.
410 The user-defined functor is called only if the inserting is success.
412 The function makes RCU lock internally.
414 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
416 template <typename Func>
417 bool insert( value_type& val, Func f )
419 return insert_at( m_pHead, val, f );
424 The operation performs inserting or changing data with lock-free manner.
426 If the item \p val not found in the list, then \p val is inserted into the list
427 iff \p bAllowInsert is \p true.
428 Otherwise, the functor \p func is called with item found.
429 The functor signature is:
432 void operator()( bool bNew, value_type& item, value_type& val );
436 - \p bNew - \p true if the item has been inserted, \p false otherwise
437 - \p item - item of the list
438 - \p val - argument \p val passed into the \p update() function
439 If new item has been inserted (i.e. \p bNew is \p true) then \p item and \p val arguments
440 refer to the same thing.
442 The functor may change non-key fields of the \p item; however, \p func must guarantee
443 that during changing no any other modifications could be made on this item by concurrent threads.
445 Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successful,
446 \p second is \p true if new item has been added or \p false if the item with \p key
447 already is in the list.
449 The function makes RCU lock internally.
451 @warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
453 template <typename Func>
454 std::pair<bool, bool> update( value_type& val, Func func, bool bAllowInsert = true )
456 return update_at( m_pHead, val, func, bAllowInsert );
459 template <typename Func>
460 CDS_DEPRECATED("ensure() is deprecated, use update()")
461 std::pair<bool, bool> ensure( value_type& val, Func func )
463 return update( val, func, true );
467 /// Unlinks the item \p val from the list
469 The function searches the item \p val in the list and unlink it from the list
470 if it is found and it is equal to \p val.
472 Difference between \p erase() and \p %unlink() functions: \p %erase() finds <i>a key</i>
473 and deletes the item found. \p %unlink() finds an item by key and deletes it
474 only if \p val is an item of that list, i.e. the pointer to the item found
475 is equal to <tt> &val </tt>.
477 The function returns \p true if success and \p false otherwise.
479 RCU \p synchronize method can be called.
480 Note that depending on RCU type used the \ref disposer call can be deferred.
482 \p disposer specified in \p Traits is called for unlinked item.
484 The function can throw cds::urcu::rcu_deadlock exception if deadlock is encountered and
485 deadlock checking policy is opt::v::rcu_throw_deadlock.
487 bool unlink( value_type& val )
489 return unlink_at( m_pHead, val );
492 /// Deletes the item from the list
494 The function searches an item with key equal to \p key in the list,
495 unlinks it from the list, and returns \p true.
496 If the item with the key equal to \p key is not found the function return \p false.
498 RCU \p synchronize method can be called.
499 Note that depending on RCU type used the \ref disposer call can be deferred.
501 \p disposer specified in \p Traits is called for deleted item.
503 The function can throw \ref cds_urcu_rcu_deadlock "cds::urcu::rcu_deadlock" exception if a deadlock is detected and
504 the deadlock checking policy is \p opt::v::rcu_throw_deadlock.
506 template <typename Q>
507 bool erase( Q const& key )
509 return erase_at( m_pHead, key, key_comparator());
512 /// Deletes the item from the list using \p pred predicate for searching
514 The function is an analog of \p erase(Q const&)
515 but \p pred is used for key comparing.
516 \p Less functor has the interface like \p std::less.
517 \p pred must imply the same element order as the comparator used for building the list.
519 \p disposer specified in \p Traits is called for deleted item.
521 template <typename Q, typename Less>
522 bool erase_with( Q const& key, Less pred )
525 return erase_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
528 /// Deletes the item from the list
530 The function searches an item with key equal to \p key in the list,
531 call \p func functor with item found, unlinks it from the list, and returns \p true.
532 The \p Func interface is
535 void operator()( value_type const& item );
539 If the item with the key equal to \p key is not found the function return \p false.
541 RCU \p synchronize method can be called.
542 Note that depending on RCU type used the \ref disposer call can be deferred.
544 \p disposer specified in \p Traits is called for deleted item.
546 The function can throw \ref cds_urcu_rcu_deadlock "cds::urcu::rcu_deadlock" exception if a deadlock is detected and
547 the deadlock checking policy is \p opt::v::rcu_throw_deadlock.
549 template <typename Q, typename Func>
550 bool erase( Q const& key, Func func )
552 return erase_at( m_pHead, key, key_comparator(), func );
555 /// Deletes the item from the list using \p pred predicate for searching
557 The function is an analog of \p erase(Q const&, Func)
558 but \p pred is used for key comparing.
559 \p Less functor has the interface like \p std::less.
560 \p pred must imply the same element order as the comparator used for building the list.
562 \p disposer specified in \p Traits is called for deleted item.
564 template <typename Q, typename Less, typename Func>
565 bool erase_with( Q const& key, Less pred, Func func )
568 return erase_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), func );
571 /// Extracts an item from the list
573 The function searches an item with key equal to \p key in the list,
574 unlinks it from the list, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the item found.
575 If \p key is not found the function returns an empty \p exempt_ptr.
577 @note The function does NOT dispose the item found. It just unlinks the item from the list
578 and returns a pointer to item found.
579 You shouldn't lock RCU for current thread before calling this function, and you should manually release
580 the returned exempt pointer before reusing it.
583 #include <cds/urcu/general_buffered.h>
584 #include <cds/intrusive/michael_list_rcu.h>
586 typedef cds::urcu::gc< general_buffered<> > rcu;
587 typedef cds::intrusive::MichaelList< rcu, Foo > rcu_michael_list;
589 rcu_michael_list theList;
592 rcu_michael_list::exempt_ptr p1;
594 // The RCU should NOT be locked when extract() is called!
595 assert( !rcu::is_locked());
597 // You can call extract() function
598 p1 = theList.extract( 10 );
600 // do something with p1
604 // We may safely release p1 here
605 // release() passes the pointer to RCU reclamation cycle:
606 // it invokes RCU retire_ptr function with the disposer you provided for the list.
610 template <typename Q>
611 exempt_ptr extract( Q const& key )
613 return exempt_ptr( extract_at( m_pHead, key, key_comparator()));
616 /// Extracts an item from the list using \p pred predicate for searching
618 This function is the analog for \p extract(Q const&)
620 The \p pred is a predicate used for key comparing.
621 \p Less has the interface like \p std::less.
622 \p pred must imply the same element order as \ref key_comparator.
624 template <typename Q, typename Less>
625 exempt_ptr extract_with( Q const& key, Less pred )
628 return exempt_ptr( extract_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>()));
631 /// Find the key \p val
633 The function searches the item with key equal to \p key
634 and calls the functor \p f for item found.
635 The interface of \p Func functor is:
638 void operator()( value_type& item, Q& key );
641 where \p item is the item found, \p key is the <tt>find</tt> function argument.
643 The functor can change non-key fields of \p item.
644 The function \p find does not serialize simultaneous access to the list \p item. If such access is
645 possible you must provide your own synchronization schema to exclude unsafe item modifications.
647 The function makes RCU lock internally.
649 The function returns \p true if \p val is found, \p false otherwise.
651 template <typename Q, typename Func>
652 bool find( Q& key, Func f )
654 return find_at( m_pHead, key, key_comparator(), f );
657 template <typename Q, typename Func>
658 bool find( Q const& key, Func f )
660 return find_at( m_pHead, key, key_comparator(), f );
664 /// Finds \p key using \p pred predicate for searching
666 The function is an analog of \p find(Q&, Func)
667 but \p pred is used for key comparing.
668 \p Less functor has the interface like \p std::less.
669 \p pred must imply the same element order as the comparator used for building the list.
671 template <typename Q, typename Less, typename Func>
672 bool find_with( Q& key, Less pred, Func f )
675 return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
678 template <typename Q, typename Less, typename Func>
679 bool find_with( Q const& key, Less pred, Func f )
682 return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
686 /// Checks whether the list contains \p key
688 The function searches the item with key equal to \p key
689 and returns \p true if it is found, and \p false otherwise.
691 template <typename Q>
692 bool contains( Q const& key )
694 return find_at( m_pHead, key, key_comparator());
697 template <typename Q>
698 CDS_DEPRECATED("deprecated, use contains()")
699 bool find( Q const& key )
701 return contains( key );
705 /// Checks whether the map contains \p key using \p pred predicate for searching
707 The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
708 \p Less functor has the interface like \p std::less.
709 \p Less must imply the same element order as the comparator used for building the list.
711 template <typename Q, typename Less>
712 bool contains( Q const& key, Less pred )
715 return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
718 template <typename Q, typename Less>
719 CDS_DEPRECATED("deprecated, use contains()")
720 bool find_with( Q const& key, Less pred )
722 return contains( key, pred );
726 /// Finds \p key and return the item found
727 /** \anchor cds_intrusive_MichaelList_rcu_get
728 The function searches the item with key equal to \p key and returns the pointer to item found.
729 If \p key is not found it returns empty \p raw_ptr object.
731 Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
733 RCU should be locked before call of this function.
734 Returned item is valid only while RCU is locked:
736 typedef cds::intrusive::MichaelList< cds::urcu::gc< cds::urcu::general_buffered<> >, foo, my_traits > ord_list;
739 typename ord_list::raw_ptr rp;
742 ord_list::rcu_lock lock;
744 rp = theList.get( 5 );
749 // Unlock RCU by rcu_lock destructor
750 // Node owned by rp can be retired by disposer at any time after RCU has been unlocked
752 // You can manually release rp after RCU-locked section
756 template <typename Q>
757 raw_ptr get( Q const& key )
759 return get_at( m_pHead, key, key_comparator());
762 /// Finds \p key and return the item found
764 The function is an analog of \ref cds_intrusive_MichaelList_rcu_get "get(Q const&)"
765 but \p pred is used for comparing the keys.
767 \p Less functor has the semantics like \p std::less but should take arguments of type \p value_type and \p Q
769 \p pred must imply the same element order as the comparator used for building the list.
771 template <typename Q, typename Less>
772 raw_ptr get_with( Q const& key, Less pred )
775 return get_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
778 /// Clears the list using default disposer
780 The function clears the list using default (provided by \p Traits class template argument) disposer functor.
782 RCU \p synchronize method can be called.
783 Note that depending on RCU type used the \ref disposer invocation can be deferred.
785 The function can throw \p cds::urcu::rcu_deadlock exception if a deadlock is encountered and
786 deadlock checking policy is \p opt::v::rcu_throw_deadlock.
791 check_deadlock_policy::check();
793 marked_node_ptr pHead;
797 pHead = m_pHead.load(memory_model::memory_order_acquire);
800 marked_node_ptr pNext( pHead->m_pNext.load(memory_model::memory_order_relaxed));
801 if ( cds_unlikely( !pHead->m_pNext.compare_exchange_weak( pNext, pNext | 1, memory_model::memory_order_acquire, memory_model::memory_order_relaxed )))
803 if ( cds_unlikely( !m_pHead.compare_exchange_weak( pHead, marked_node_ptr(pNext.ptr()), memory_model::memory_order_release, memory_model::memory_order_relaxed )))
808 dispose_node( pHead.ptr());
813 /// Check if the list is empty
816 return m_pHead.load( memory_model::memory_order_relaxed ).all() == nullptr;
819 /// Returns list's item count
821 The value returned depends on item counter provided by \p Traits. For \p atomicity::empty_item_counter,
822 this function always returns 0.
824 @note Even if you use real item counter and it returns 0, this fact does not mean that the list
825 is empty. To check list emptyness use \p empty() method.
829 return m_ItemCounter.value();
832 /// Returns const reference to internal statistics
833 stat const& statistics() const
840 static void clear_links( node_type * pNode )
842 pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_release );
843 pNode->m_pDelChain = nullptr;
846 static void dispose_node( node_type * pNode )
849 assert( !gc::is_locked());
851 gc::template retire_ptr<clear_and_dispose>( node_traits::to_value_ptr( *pNode ));
854 static void dispose_chain( node_type * pChain )
857 assert( !gc::is_locked());
859 auto f = [&pChain]() -> cds::urcu::retired_ptr {
860 node_type * p = pChain;
862 pChain = p->m_pDelChain;
863 return cds::urcu::make_retired_ptr<clear_and_dispose>( node_traits::to_value_ptr( p ));
865 return cds::urcu::make_retired_ptr<clear_and_dispose>( static_cast<value_type *>(nullptr));
867 gc::batch_retire( std::ref( f ));
871 bool link_node( node_type * pNode, position& pos )
873 assert( pNode != nullptr );
874 link_checker::is_empty( pNode );
876 marked_node_ptr p( pos.pCur );
877 pNode->m_pNext.store( p, memory_model::memory_order_release );
878 if ( cds_likely( pos.pPrev->compare_exchange_strong( p, marked_node_ptr( pNode ), memory_model::memory_order_release, atomics::memory_order_relaxed )))
881 pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
885 static void link_to_remove_chain( position& pos, node_type * pDel )
887 assert( pDel->m_pDelChain == nullptr );
889 pDel->m_pDelChain = pos.pDelChain;
890 pos.pDelChain = pDel;
893 bool unlink_node( position& pos, erase_node_mask nMask )
895 assert( gc::is_locked());
897 // Mark the node (logical deletion)
898 marked_node_ptr next( pos.pNext, 0 );
900 if ( cds_likely( pos.pCur->m_pNext.compare_exchange_strong( next, next | nMask, memory_model::memory_order_release, atomics::memory_order_relaxed ))) {
902 // Try physical removal - fast path
903 marked_node_ptr cur( pos.pCur );
904 if ( cds_likely( pos.pPrev->compare_exchange_strong( cur, marked_node_ptr( pos.pNext ), memory_model::memory_order_acquire, atomics::memory_order_relaxed ))) {
905 if ( nMask == erase_mask )
906 link_to_remove_chain( pos, pos.pCur );
910 search( pos.refHead, *node_traits::to_value_ptr( pos.pCur ), pos, key_comparator());
917 // split-list support
918 bool insert_aux_node( node_type * pNode )
920 return insert_aux_node( m_pHead, pNode );
923 // split-list support
924 bool insert_aux_node( atomic_node_ptr& refHead, node_type * pNode )
926 assert( pNode != nullptr );
928 // Hack: convert node_type to value_type.
929 // In principle, auxiliary node can be non-reducible to value_type
930 // We assume that comparator can correctly distinguish between aux and regular node.
931 return insert_at( refHead, *node_traits::to_value_ptr( pNode ));
934 bool insert_at( atomic_node_ptr& refHead, value_type& val )
936 position pos( refHead );
939 return insert_at_locked( pos, val );
943 template <typename Func>
944 bool insert_at( atomic_node_ptr& refHead, value_type& val, Func f )
946 position pos( refHead );
951 if ( search( refHead, val, pos, key_comparator())) {
952 m_Stat.onInsertFailed();
956 if ( link_node( node_traits::to_node_ptr( val ), pos )) {
959 m_Stat.onInsertSuccess();
964 node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
965 m_Stat.onInsertRetry();
971 iterator insert_at_( atomic_node_ptr& refHead, value_type& val )
974 if ( insert_at_locked( refHead, val ))
975 return iterator( node_traits::to_node_ptr( val ));
979 template <typename Func>
980 std::pair<iterator, bool> update_at_( atomic_node_ptr& refHead, value_type& val, Func func, bool bInsert )
982 position pos( refHead );
985 return update_at_locked( pos, val, func, bInsert );
989 template <typename Func>
990 std::pair<bool, bool> update_at( atomic_node_ptr& refHead, value_type& val, Func func, bool bInsert )
992 position pos( refHead );
995 std::pair<iterator, bool> ret = update_at_locked( pos, val, func, bInsert );
996 return std::make_pair( ret.first != end(), ret.second );
1000 bool unlink_at( atomic_node_ptr& refHead, value_type& val )
1002 position pos( refHead );
1004 check_deadlock_policy::check();
1009 if ( !search( refHead, val, pos, key_comparator()) || node_traits::to_value_ptr( *pos.pCur ) != &val ) {
1010 m_Stat.onEraseFailed();
1013 if ( !unlink_node( pos, erase_mask )) {
1015 m_Stat.onEraseRetry();
1021 m_Stat.onEraseSuccess();
1026 template <typename Q, typename Compare, typename Func>
1027 bool erase_at( position& pos, Q const& val, Compare cmp, Func f )
1030 check_deadlock_policy::check();
1036 if ( !search( pos.refHead, val, pos, cmp )) {
1037 m_Stat.onEraseFailed();
1041 // store pCur since it may be changed by unlink_node() slow path
1043 if ( !unlink_node( pos, erase_mask )) {
1045 m_Stat.onEraseRetry();
1050 f( *node_traits::to_value_ptr( pDel ));
1052 m_Stat.onEraseSuccess();
1057 template <typename Q, typename Compare, typename Func>
1058 bool erase_at( atomic_node_ptr& refHead, Q const& val, Compare cmp, Func f )
1060 position pos( refHead );
1061 return erase_at( pos, val, cmp, f );
1064 template <typename Q, typename Compare>
1065 bool erase_at( atomic_node_ptr& refHead, const Q& val, Compare cmp )
1067 position pos( refHead );
1068 return erase_at( pos, val, cmp, [](value_type const&){} );
1071 template <typename Q, typename Compare >
1072 value_type * extract_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
1074 position pos( refHead );
1076 assert( !gc::is_locked()) ; // RCU must not be locked!!!
1078 node_type * pExtracted;
1082 if ( !search( refHead, val, pos, cmp )) {
1083 m_Stat.onEraseFailed();
1087 // store pCur since it may be changed by unlink_node() slow path
1088 pExtracted = pos.pCur;
1089 if ( !unlink_node( pos, extract_mask )) {
1091 m_Stat.onEraseRetry();
1096 value_type * pRet = node_traits::to_value_ptr( pExtracted );
1097 assert( pExtracted->m_pDelChain == nullptr );
1098 m_Stat.onEraseSuccess();
1104 template <typename Q, typename Compare, typename Func>
1105 bool find_at( atomic_node_ptr& refHead, Q& val, Compare cmp, Func f )
1107 position pos( refHead );
1111 if ( search( refHead, val, pos, cmp )) {
1112 assert( pos.pCur != nullptr );
1113 f( *node_traits::to_value_ptr( *pos.pCur ), val );
1114 m_Stat.onFindSuccess();
1119 m_Stat.onFindFailed();
1123 template <typename Q, typename Compare>
1124 bool find_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
1126 position pos( refHead );
1129 return find_at_locked( pos, val, cmp ) != cend();
1133 template <typename Q, typename Compare>
1134 raw_ptr get_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
1136 // RCU should be locked!
1137 assert(gc::is_locked());
1139 position pos( refHead );
1141 if ( search( refHead, val, pos, cmp )) {
1142 m_Stat.onFindSuccess();
1143 return raw_ptr( node_traits::to_value_ptr( pos.pCur ), raw_ptr_disposer( pos ));
1146 m_Stat.onFindFailed();
1147 return raw_ptr( raw_ptr_disposer( pos ));
1154 template <typename Q, typename Compare>
1155 bool search( atomic_node_ptr& refHead, const Q& val, position& pos, Compare cmp )
1157 // RCU lock should be locked!!!
1158 assert( gc::is_locked());
1160 atomic_node_ptr * pPrev;
1161 marked_node_ptr pNext;
1162 marked_node_ptr pCur;
1168 pCur = pPrev->load(memory_model::memory_order_acquire);
1175 pos.pNext = nullptr;
1179 pNext = pCur->m_pNext.load(memory_model::memory_order_acquire);
1181 if ( cds_unlikely( pPrev->load(memory_model::memory_order_acquire) != pCur
1182 || pNext != pCur->m_pNext.load(memory_model::memory_order_acquire )))
1188 if ( pNext.bits()) {
1189 // pCur is marked as deleted. Try to unlink it from the list
1190 if ( cds_likely( pPrev->compare_exchange_weak( pCur, marked_node_ptr( pNext.ptr()), memory_model::memory_order_acquire, atomics::memory_order_relaxed ))) {
1191 if ( pNext.bits() == erase_mask )
1192 link_to_remove_chain( pos, pCur.ptr());
1193 m_Stat.onHelpingSuccess();
1196 m_Stat.onHelpingFailed();
1200 assert( pCur.ptr() != nullptr );
1201 int nCmp = cmp( *node_traits::to_value_ptr( pCur.ptr()), val );
1204 pos.pCur = pCur.ptr();
1205 pos.pNext = pNext.ptr();
1208 pPrev = &( pCur->m_pNext );
1216 bool insert_at_locked( position& pos, value_type& val )
1218 // RCU lock should be locked!!!
1219 assert( gc::is_locked());
1222 if ( search( pos.refHead, val, pos, key_comparator())) {
1223 m_Stat.onInsertFailed();
1227 if ( link_node( node_traits::to_node_ptr( val ), pos )) {
1229 m_Stat.onInsertSuccess();
1234 node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
1235 m_Stat.onInsertRetry();
1239 template <typename Func>
1240 std::pair<iterator, bool> update_at_locked( position& pos, value_type& val, Func func, bool bInsert )
1242 // RCU should be locked!!!
1243 assert( gc::is_locked());
1246 if ( search( pos.refHead, val, pos, key_comparator())) {
1247 assert( key_comparator()( val, *node_traits::to_value_ptr( *pos.pCur )) == 0 );
1249 func( false, *node_traits::to_value_ptr( *pos.pCur ), val );
1250 m_Stat.onUpdateExisting();
1251 return std::make_pair( iterator( pos.pCur ), false );
1255 m_Stat.onUpdateFailed();
1256 return std::make_pair( end(), false );
1259 if ( link_node( node_traits::to_node_ptr( val ), pos )) {
1261 func( true, val , val );
1262 m_Stat.onUpdateNew();
1263 return std::make_pair( iterator( node_traits::to_node_ptr( val )), true );
1266 // clear the next field
1267 node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
1268 m_Stat.onUpdateRetry();
1273 template <typename Q, typename Compare>
1274 const_iterator find_at_locked( position& pos, Q const& val, Compare cmp )
1276 assert( gc::is_locked());
1278 if ( search( pos.refHead, val, pos, cmp )) {
1279 assert( pos.pCur != nullptr );
1280 m_Stat.onFindSuccess();
1281 return const_iterator( pos.pCur );
1284 m_Stat.onFindFailed();
1290 }} // namespace cds::intrusive
1292 #endif // #ifndef CDSLIB_INTRUSIVE_MICHAEL_LIST_NOGC_H