-//$$CDS-header$$
+/*
+ This file is a part of libcds - Concurrent Data Structures library
+
+ (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016
+
+ Source code repo: http://github.com/khizmax/libcds/
+ Download: http://sourceforge.net/projects/libcds/files/
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice, this
+ list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright notice,
+ this list of conditions and the following disclaimer in the documentation
+ and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
#ifndef CDSLIB_INTRUSIVE_MICHAEL_LIST_RCU_H
#define CDSLIB_INTRUSIVE_MICHAEL_LIST_RCU_H
#include <cds/details/binary_functor_wrapper.h>
#include <cds/details/make_const_type.h>
#include <cds/urcu/exempt_ptr.h>
+#include <cds/urcu/raw_ptr.h>
+#include <cds/intrusive/details/raw_ptr_disposer.h>
namespace cds { namespace intrusive {
+ //@cond
+ namespace michael_list {
+
+ /// Node specialization for uRCU
+ template <class RCU, typename Tag>
+ struct node< cds::urcu::gc< RCU >, Tag >
+ {
+ typedef cds::urcu::gc< RCU > gc; ///< Garbage collector
+ typedef Tag tag; ///< tag
+
+ typedef cds::details::marked_ptr<node, 3> marked_ptr; ///< marked pointer
+ typedef typename gc::template atomic_marked_ptr<marked_ptr> atomic_marked_ptr; ///< atomic marked pointer specific for GC
+
+ atomic_marked_ptr m_pNext; ///< pointer to the next node in the container
+ node * m_pDelChain; ///< Deleted node chain (local for a thread)
+
+ CDS_CONSTEXPR node() CDS_NOEXCEPT
+ : m_pNext( nullptr )
+ , m_pDelChain( nullptr )
+ {}
+ };
+ } // namespace michael_list
+ //@endcond
+
/// Michael's lock-free ordered single-linked list (template specialization for \ref cds_urcu_desc "RCU")
/** @ingroup cds_intrusive_list
\anchor cds_intrusive_MichaelList_rcu
typedef typename get_node_traits< value_type, node_type, hook>::type node_traits ; ///< node traits
typedef typename michael_list::get_link_checker< node_type, traits::link_checker >::type link_checker; ///< link checker
- typedef cds::urcu::gc<RCU> gc; ///< RCU schema
- typedef typename traits::back_off back_off; ///< back-off strategy
- typedef typename traits::item_counter item_counter; ///< Item counting policy used
- typedef typename traits::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
- typedef typename traits::rcu_check_deadlock rcu_check_deadlock; ///< Deadlock checking policy
+ typedef cds::urcu::gc<RCU> gc; ///< RCU schema
+ typedef typename traits::back_off back_off; ///< back-off strategy
+ typedef typename traits::item_counter item_counter; ///< Item counting policy used
+ typedef typename traits::memory_model memory_model; ///< Memory ordering. See cds::opt::memory_model option
+ typedef typename traits::rcu_check_deadlock rcu_check_deadlock; ///< Deadlock checking policy
+ typedef typename traits::stat stat; ///< Internal statistics
typedef typename gc::scoped_lock rcu_lock ; ///< RCU scoped lock
- static CDS_CONSTEXPR const bool c_bExtractLockExternal = true; ///< Group of \p extract_xxx functions require external locking
+ static CDS_CONSTEXPR const bool c_bExtractLockExternal = false; ///< Group of \p extract_xxx functions do not require external locking
//@cond
// Rebind traits (split-list support)
, typename cds::opt::make_options< traits, Options...>::type
> type;
};
+
+ // Stat selector
+ template <typename Stat>
+ using select_stat_wrapper = michael_list::select_stat_wrapper< Stat >;
//@endcond
protected:
- typedef typename node_type::marked_ptr marked_node_ptr ; ///< Marked node pointer
- typedef typename node_type::atomic_marked_ptr atomic_node_ptr ; ///< Atomic node pointer
- typedef atomic_node_ptr auxiliary_head ; ///< Auxiliary head type (for split-list support)
+ typedef typename node_type::marked_ptr marked_node_ptr; ///< Marked node pointer
+ typedef typename node_type::atomic_marked_ptr atomic_node_ptr; ///< Atomic node pointer
+ typedef atomic_node_ptr auxiliary_head; ///< Auxiliary head type (for split-list support)
- atomic_node_ptr m_pHead ; ///< Head pointer
- item_counter m_ItemCounter ; ///< Item counter
+ atomic_node_ptr m_pHead; ///< Head pointer
+ item_counter m_ItemCounter; ///< Item counter
+ stat m_Stat; ///< Internal statistics
+ protected:
//@cond
- /// Position pointer for item search
- struct position {
- atomic_node_ptr * pPrev ; ///< Previous node
- node_type * pCur ; ///< Current node
- node_type * pNext ; ///< Next node
+ enum erase_node_mask
+ {
+ erase_mask = 1,
+ extract_mask = 3
};
typedef cds::urcu::details::check_deadlock_policy< gc, rcu_check_deadlock> check_deadlock_policy;
static void clear_links( node_type * pNode )
{
- pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
+ pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_release );
+ pNode->m_pDelChain = nullptr;
}
struct clear_and_dispose {
disposer()( p );
}
};
- //@endcond
-
- public:
- using exempt_ptr = cds::urcu::exempt_ptr< gc, value_type, value_type, clear_and_dispose, void >; ///< pointer to extracted node
-
- protected:
- //@cond
static void dispose_node( node_type * pNode )
{
gc::template retire_ptr<clear_and_dispose>( node_traits::to_value_ptr( *pNode ) );
}
+ static void dispose_chain( node_type * pChain )
+ {
+ if ( pChain ) {
+ assert( !gc::is_locked() );
+
+ auto f = [&pChain]() -> cds::urcu::retired_ptr {
+ node_type * p = pChain;
+ if ( p ) {
+ pChain = p->m_pDelChain;
+ return cds::urcu::make_retired_ptr<clear_and_dispose>( node_traits::to_value_ptr( p ));
+ }
+ return cds::urcu::make_retired_ptr<clear_and_dispose>( static_cast<value_type *>(nullptr));
+ };
+ gc::batch_retire(std::ref(f));
+ }
+ }
+
+ /// Position pointer for item search
+ struct position {
+ atomic_node_ptr * pPrev ; ///< Previous node
+ node_type * pCur ; ///< Current node
+ node_type * pNext ; ///< Next node
+
+ atomic_node_ptr& refHead;
+ node_type * pDelChain; ///< Head of deleted node chain
+
+ position( atomic_node_ptr& head )
+ : refHead( head )
+ , pDelChain( nullptr )
+ {}
+
+ ~position()
+ {
+ dispose_chain( pDelChain );
+ }
+ };
+
+ //@endcond
+
+ public:
+ using exempt_ptr = cds::urcu::exempt_ptr< gc, value_type, value_type, clear_and_dispose, void >; ///< pointer to extracted node
+
+ private:
+ //@cond
+ struct chain_disposer {
+ void operator()( node_type * pChain ) const
+ {
+ dispose_chain( pChain );
+ }
+ };
+ typedef cds::intrusive::details::raw_ptr_disposer< gc, node_type, chain_disposer> raw_ptr_disposer;
+ //@endcond
+
+ public:
+ /// Result of \p get(), \p get_with() functions - pointer to the node found
+ typedef cds::urcu::raw_ptr< gc, value_type, raw_ptr_disposer > raw_ptr;
+
+ protected:
+ //@cond
+
bool link_node( node_type * pNode, position& pos )
{
assert( pNode != nullptr );
link_checker::is_empty( pNode );
marked_node_ptr p( pos.pCur );
- pNode->m_pNext.store( p, memory_model::memory_order_relaxed );
- return pos.pPrev->compare_exchange_strong( p, marked_node_ptr(pNode), memory_model::memory_order_release, atomics::memory_order_relaxed );
+ pNode->m_pNext.store( p, memory_model::memory_order_release );
+ if ( cds_likely( pos.pPrev->compare_exchange_strong( p, marked_node_ptr(pNode), memory_model::memory_order_release, atomics::memory_order_relaxed )))
+ return true;
+
+ pNode->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
+ return false;
+ }
+
+ static void link_to_remove_chain( position& pos, node_type * pDel )
+ {
+ assert( pDel->m_pDelChain == nullptr );
+
+ pDel->m_pDelChain = pos.pDelChain;
+ pos.pDelChain = pDel;
}
- bool unlink_node( position& pos )
+ bool unlink_node( position& pos, erase_node_mask nMask )
{
- // Mark the node (logical deleting)
+ assert(gc::is_locked() );
+
+ // Mark the node (logical deletion)
marked_node_ptr next(pos.pNext, 0);
- if ( pos.pCur->m_pNext.compare_exchange_strong( next, marked_node_ptr(pos.pNext, 1), memory_model::memory_order_acquire, atomics::memory_order_relaxed )) {
+
+ if ( cds_likely( pos.pCur->m_pNext.compare_exchange_strong( next, next | nMask, memory_model::memory_order_release, atomics::memory_order_relaxed ))) {
+
+ // Try physical removal - fast path
marked_node_ptr cur(pos.pCur);
- if ( pos.pPrev->compare_exchange_strong( cur, marked_node_ptr( pos.pNext ), memory_model::memory_order_release, atomics::memory_order_relaxed ))
- return true;
- next |= 1;
- CDS_VERIFY( pos.pCur->m_pNext.compare_exchange_strong( next, next ^ 1, memory_model::memory_order_release, atomics::memory_order_relaxed ));
+ if ( cds_likely( pos.pPrev->compare_exchange_strong(cur, marked_node_ptr(pos.pNext), memory_model::memory_order_acquire, atomics::memory_order_relaxed ))) {
+ if ( nMask == erase_mask )
+ link_to_remove_chain( pos, pos.pCur );
+ }
+ else {
+ // Slow path
+ search( pos.refHead, *node_traits::to_value_ptr( pos.pCur ), pos, key_comparator() );
+ }
+ return true;
}
return false;
}
//@endcond
public:
+ ///@name Forward iterators (thread-safe only under RCU lock)
+ //@{
/// Forward iterator
+ /**
+ You may safely use iterators in multi-threaded environment only under RCU lock.
+ Otherwise, a crash is possible if another thread deletes the item the iterator points to.
+ */
typedef iterator_type<false> iterator;
+
/// Const forward iterator
typedef iterator_type<true> const_iterator;
{
return const_iterator();
}
+ //@}
public:
/// Default constructor initializes empty list
static_assert( (std::is_same< gc, typename node_type::gc >::value), "GC and node_type::gc must be the same type" );
}
+ //@cond
+ template <typename Stat, typename = std::enable_if<std::is_same<stat, michael_list::wrapped_stat<Stat>>::value >>
+ explicit MichaelList( Stat& st )
+ : m_pHead( nullptr )
+ , m_Stat( st )
+ {}
+ //@endcond
+
/// Destroy list
~MichaelList()
{
return insert_at( m_pHead, val, f );
}
- /// Ensures that the \p item exists in the list
+ /// Updates the item
/**
The operation performs inserting or changing data with lock-free manner.
- If the item \p val not found in the list, then \p val is inserted into the list.
+ If the item \p val not found in the list, then \p val is inserted into the list
+ iff \p bAllowInsert is \p true.
Otherwise, the functor \p func is called with item found.
The functor signature is:
\code
with arguments:
- \p bNew - \p true if the item has been inserted, \p false otherwise
- \p item - item of the list
- - \p val - argument \p val passed into the \p ensure function
+ - \p val - argument \p val passed into the \p update() function
If new item has been inserted (i.e. \p bNew is \p true) then \p item and \p val arguments
refer to the same thing.
The functor may change non-key fields of the \p item; however, \p func must guarantee
that during changing no any other modifications could be made on this item by concurrent threads.
- Returns <tt> std::pair<bool, bool> </tt> where \p first is true if operation is successfull,
- \p second is true if new item has been added or \p false if the item with \p key
+ Returns <tt> std::pair<bool, bool> </tt> where \p first is \p true if operation is successful,
+ \p second is \p true if new item has been added or \p false if the item with \p key
already is in the list.
The function makes RCU lock internally.
@warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
*/
template <typename Func>
+ std::pair<bool, bool> update( value_type& val, Func func, bool bAllowInsert = true )
+ {
+ return update_at( m_pHead, val, func, bAllowInsert );
+ }
+ //@cond
+ template <typename Func>
+ CDS_DEPRECATED("ensure() is deprecated, use update()")
std::pair<bool, bool> ensure( value_type& val, Func func )
{
- return ensure_at( m_pHead, val, func );
+ return update( val, func, true );
}
+ //@endcond
/// Unlinks the item \p val from the list
/**
The function searches the item \p val in the list and unlink it from the list
if it is found and it is equal to \p val.
- Difference between \ref erase and \p unlink functions: \p erase finds <i>a key</i>
- and deletes the item found. \p unlink finds an item by key and deletes it
+ Difference between \p erase() and \p %unlink() functions: \p %erase() finds <i>a key</i>
+ and deletes the item found. \p %unlink() finds an item by key and deletes it
only if \p val is an item of that list, i.e. the pointer to the item found
is equal to <tt> &val </tt>.
RCU \p synchronize method can be called.
Note that depending on RCU type used the \ref disposer call can be deferred.
+ \p disposer specified in \p Traits is called for unlinked item.
+
The function can throw cds::urcu::rcu_deadlock exception if deadlock is encountered and
deadlock checking policy is opt::v::rcu_throw_deadlock.
*/
}
/// Deletes the item from the list
- /** \anchor cds_intrusive_MichaelList_rcu_erase_val
+ /**
The function searches an item with key equal to \p key in the list,
unlinks it from the list, and returns \p true.
If the item with the key equal to \p key is not found the function return \p false.
RCU \p synchronize method can be called.
Note that depending on RCU type used the \ref disposer call can be deferred.
+ \p disposer specified in \p Traits is called for deleted item.
+
The function can throw \ref cds_urcu_rcu_deadlock "cds::urcu::rcu_deadlock" exception if a deadlock is detected and
the deadlock checking policy is \p opt::v::rcu_throw_deadlock.
*/
/// Deletes the item from the list using \p pred predicate for searching
/**
- The function is an analog of \ref cds_intrusive_MichaelList_rcu_erase_val "erase(Q const&)"
+ The function is an analog of \p erase(Q const&)
but \p pred is used for key comparing.
\p Less functor has the interface like \p std::less.
\p pred must imply the same element order as the comparator used for building the list.
+
+ \p disposer specified in \p Traits is called for deleted item.
*/
template <typename Q, typename Less>
bool erase_with( Q const& key, Less pred )
}
/// Deletes the item from the list
- /** \anchor cds_intrusive_MichaelList_rcu_erase_func
+ /**
The function searches an item with key equal to \p key in the list,
call \p func functor with item found, unlinks it from the list, and returns \p true.
The \p Func interface is
RCU \p synchronize method can be called.
Note that depending on RCU type used the \ref disposer call can be deferred.
+ \p disposer specified in \p Traits is called for deleted item.
+
The function can throw \ref cds_urcu_rcu_deadlock "cds::urcu::rcu_deadlock" exception if a deadlock is detected and
the deadlock checking policy is \p opt::v::rcu_throw_deadlock.
*/
/// Deletes the item from the list using \p pred predicate for searching
/**
- The function is an analog of \ref cds_intrusive_MichaelList_rcu_erase_func "erase(Q const&, Func)"
+ The function is an analog of \p erase(Q const&, Func)
but \p pred is used for key comparing.
\p Less functor has the interface like \p std::less.
\p pred must imply the same element order as the comparator used for building the list.
+
+ \p disposer specified in \p Traits is called for deleted item.
*/
template <typename Q, typename Less, typename Func>
bool erase_with( Q const& key, Less pred, Func func )
/// Extracts an item from the list
/**
- @anchor cds_intrusive_MichaelList_rcu_extract
The function searches an item with key equal to \p key in the list,
unlinks it from the list, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the item found.
If \p key is not found the function returns an empty \p exempt_ptr.
- @note The function does NOT call RCU read-side lock or synchronization,
- and does NOT dispose the item found. It just unlinks the item from the list
+ @note The function does NOT dispose the item found. It just unlinks the item from the list
and returns a pointer to item found.
- You should lock RCU before calling this function, and you should manually release
- \p dest exempt pointer outside the RCU lock before reusing the pointer.
+ You shouldn't lock RCU for current thread before calling this function, and you should manually release
+ the returned exempt pointer before reusing it.
\code
#include <cds/urcu/general_buffered.h>
// ...
rcu_michael_list::exempt_ptr p1;
- {
- // first, we should lock RCU
- rcu::scoped_lock sl;
-
- // Now, you can apply extract function
- // Note that you must not delete the item found inside the RCU lock
- p1 = theList.extract( 10 )
- if ( p1 ) {
- // do something with p1
- ...
- }
+
+ // The RCU should NOT be locked when extract() is called!
+ assert( !rcu::is_locked() );
+
+ // You can call extract() function
+ p1 = theList.extract( 10 );
+ if ( p1 ) {
+ // do something with p1
+ ...
}
// We may safely release p1 here
/// Extracts an item from the list using \p pred predicate for searching
/**
- This function is the analog for \ref cds_intrusive_MichaelList_rcu_extract "extract(exempt_ptr&, Q const&)".
+ This function is the analog for \p extract(Q const&)
The \p pred is a predicate used for key comparing.
\p Less has the interface like \p std::less.
}
/// Find the key \p val
- /** \anchor cds_intrusive_MichaelList_rcu_find_func
+ /**
The function searches the item with key equal to \p key
and calls the functor \p f for item found.
The interface of \p Func functor is:
The function returns \p true if \p val is found, \p false otherwise.
*/
template <typename Q, typename Func>
- bool find( Q& key, Func f ) const
+ bool find( Q& key, Func f )
{
- return find_at( const_cast<atomic_node_ptr&>(m_pHead), key, key_comparator(), f );
+ return find_at( m_pHead, key, key_comparator(), f );
}
//@cond
template <typename Q, typename Func>
- bool find( Q const& key, Func f ) const
+ bool find( Q const& key, Func f )
{
- return find_at( const_cast<atomic_node_ptr&>(m_pHead), key, key_comparator(), f );
+ return find_at( m_pHead, key, key_comparator(), f );
}
//@endcond
/// Finds \p key using \p pred predicate for searching
/**
- The function is an analog of \ref cds_intrusive_MichaelList_rcu_find_func "find(Q&, Func)"
+ The function is an analog of \p find(Q&, Func)
but \p pred is used for key comparing.
\p Less functor has the interface like \p std::less.
\p pred must imply the same element order as the comparator used for building the list.
*/
template <typename Q, typename Less, typename Func>
- bool find_with( Q& key, Less pred, Func f ) const
+ bool find_with( Q& key, Less pred, Func f )
{
CDS_UNUSED( pred );
- return find_at( const_cast<atomic_node_ptr&>( m_pHead ), key, cds::opt::details::make_comparator_from_less<Less>(), f );
+ return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
}
//@cond
template <typename Q, typename Less, typename Func>
- bool find_with( Q const& key, Less pred, Func f ) const
+ bool find_with( Q const& key, Less pred, Func f )
{
CDS_UNUSED( pred );
- return find_at( const_cast<atomic_node_ptr&>(m_pHead), key, cds::opt::details::make_comparator_from_less<Less>(), f );
+ return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>(), f );
}
//@endcond
- /// Finds \p key
- /** \anchor cds_intrusive_MichaelList_rcu_find_val
+ /// Checks whether the list contains \p key
+ /**
The function searches the item with key equal to \p key
- and returns \p true if \p val found or \p false otherwise.
+ and returns \p true if it is found, and \p false otherwise.
*/
template <typename Q>
- bool find( Q const& key ) const
+ bool contains( Q const& key )
+ {
+ return find_at( m_pHead, key, key_comparator() );
+ }
+ //@cond
+ template <typename Q>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find( Q const& key )
{
- return find_at( const_cast<atomic_node_ptr&>( m_pHead ), key, key_comparator() );
+ return contains( key );
}
+ //@endcond
- /// Finds \p key using \p pred predicate for searching
+ /// Checks whether the map contains \p key using \p pred predicate for searching
/**
- The function is an analog of \ref cds_intrusive_MichaelList_rcu_find_val "find(Q const&)"
- but \p pred is used for key comparing.
+ The function is an analog of <tt>contains( key )</tt> but \p pred is used for key comparing.
\p Less functor has the interface like \p std::less.
- \p pred must imply the same element order as the comparator used for building the list.
+ \p Less must imply the same element order as the comparator used for building the list.
*/
template <typename Q, typename Less>
- bool find_with( Q const& key, Less pred ) const
+ bool contains( Q const& key, Less pred )
{
CDS_UNUSED( pred );
- return find_at( const_cast<atomic_node_ptr&>( m_pHead ), key, cds::opt::details::make_comparator_from_less<Less>() );
+ return find_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>() );
}
+ //@cond
+ template <typename Q, typename Less>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find_with( Q const& key, Less pred )
+ {
+ return contains( key, pred );
+ }
+ //@endcond
/// Finds \p key and return the item found
/** \anchor cds_intrusive_MichaelList_rcu_get
The function searches the item with key equal to \p key and returns the pointer to item found.
- If \p key is not found it returns \p nullptr.
+ If \p key is not found it returns empty \p raw_ptr object.
Note the compare functor should accept a parameter of type \p Q that can be not the same as \p value_type.
typedef cds::intrusive::MichaelList< cds::urcu::gc< cds::urcu::general_buffered<> >, foo, my_traits > ord_list;
ord_list theList;
// ...
+ typename ord_list::raw_ptr rp;
{
// Lock RCU
ord_list::rcu_lock lock;
- foo * pVal = theList.get( 5 );
- if ( pVal ) {
- // Deal with pVal
+ rp = theList.get( 5 );
+ if ( rp ) {
+ // Deal with rp
//...
}
// Unlock RCU by rcu_lock destructor
- // pVal can be retired by disposer at any time after RCU has been unlocked
+ // Node owned by rp can be retired by disposer at any time after RCU has been unlocked
}
+ // You can manually release rp after RCU-locked section
+ rp.release();
\endcode
*/
template <typename Q>
- value_type * get( Q const& key ) const
+ raw_ptr get( Q const& key )
{
- return get_at( const_cast<atomic_node_ptr&>( m_pHead ), key, key_comparator());
+ return get_at( m_pHead, key, key_comparator());
}
/// Finds \p key and return the item found
\p pred must imply the same element order as the comparator used for building the list.
*/
template <typename Q, typename Less>
- value_type * get_with( Q const& key, Less pred ) const
+ raw_ptr get_with( Q const& key, Less pred )
{
CDS_UNUSED( pred );
- return get_at( const_cast<atomic_node_ptr&>( m_pHead ), key, cds::opt::details::make_comparator_from_less<Less>());
+ return get_at( m_pHead, key, cds::opt::details::make_comparator_from_less<Less>());
}
/// Clears the list using default disposer
RCU \p synchronize method can be called.
Note that depending on RCU type used the \ref disposer invocation can be deferred.
- The function can throw cds::urcu::rcu_deadlock exception if an deadlock is encountered and
- deadlock checking policy is opt::v::rcu_throw_deadlock.
+ The function can throw \p cds::urcu::rcu_deadlock exception if a deadlock is encountered and
+ deadlock checking policy is \p opt::v::rcu_throw_deadlock.
*/
void clear()
{
for (;;) {
{
rcu_lock l;
- pHead = m_pHead.load(memory_model::memory_order_consume);
+ pHead = m_pHead.load(memory_model::memory_order_acquire);
if ( !pHead.ptr() )
break;
marked_node_ptr pNext( pHead->m_pNext.load(memory_model::memory_order_relaxed) );
- if ( !pHead->m_pNext.compare_exchange_weak( pNext, pNext | 1, memory_model::memory_order_acquire, memory_model::memory_order_relaxed ))
+ if ( cds_unlikely( !pHead->m_pNext.compare_exchange_weak( pNext, pNext | 1, memory_model::memory_order_acquire, memory_model::memory_order_relaxed )))
continue;
- if ( !m_pHead.compare_exchange_weak( pHead, marked_node_ptr(pNext.ptr()), memory_model::memory_order_release, memory_model::memory_order_relaxed ))
+ if ( cds_unlikely( !m_pHead.compare_exchange_weak( pHead, marked_node_ptr(pNext.ptr()), memory_model::memory_order_release, memory_model::memory_order_relaxed )))
continue;
}
return m_ItemCounter.value();
}
+ /// Returns const reference to internal statistics
+ stat const& statistics() const
+ {
+ return m_Stat;
+ }
protected:
//@cond
// split-list support
return insert_at( refHead, *node_traits::to_value_ptr( pNode ) );
}
- bool insert_at( atomic_node_ptr& refHead, value_type& val, bool bLock = true )
+ bool insert_at( atomic_node_ptr& refHead, value_type& val )
{
- link_checker::is_empty( node_traits::to_node_ptr( val ) );
- position pos;
-
- rcu_lock l( bLock );
- while ( true ) {
- if ( search( refHead, val, pos, key_comparator() ) )
- return false;
-
- if ( link_node( node_traits::to_node_ptr( val ), pos ) ) {
- ++m_ItemCounter;
- return true;
- }
-
- // clear next field
- node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
+ position pos( refHead );
+ {
+ rcu_lock l;
+ return insert_at_locked( pos, val );
}
}
template <typename Func>
bool insert_at( atomic_node_ptr& refHead, value_type& val, Func f )
{
- link_checker::is_empty( node_traits::to_node_ptr( val ) );
- position pos;
+ position pos( refHead );
- rcu_lock l;
- while ( true ) {
- if ( search( refHead, val, pos, key_comparator() ) )
- return false;
+ {
+ rcu_lock l;
+ while ( true ) {
+ if ( search( refHead, val, pos, key_comparator())) {
+ m_Stat.onInsertFailed();
+ return false;
+ }
- if ( link_node( node_traits::to_node_ptr( val ), pos ) ) {
- f( val );
- ++m_ItemCounter;
- return true;
- }
+ if ( link_node( node_traits::to_node_ptr( val ), pos ) ) {
+ f( val );
+ ++m_ItemCounter;
+ m_Stat.onInsertSuccess();
+ return true;
+ }
- // clear next field
- node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
+ // clear next field
+ node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
+ m_Stat.onInsertRetry();
+ }
}
+
}
- iterator insert_at_( atomic_node_ptr& refHead, value_type& val, bool bLock = true )
+ iterator insert_at_( atomic_node_ptr& refHead, value_type& val )
{
- rcu_lock l( bLock );
- if ( insert_at( refHead, val, false ))
+ rcu_lock l;
+ if ( insert_at_locked( refHead, val ))
return iterator( node_traits::to_node_ptr( val ));
return end();
}
template <typename Func>
- std::pair<iterator, bool> ensure_at_( atomic_node_ptr& refHead, value_type& val, Func func, bool bLock = true )
+ std::pair<iterator, bool> update_at_( atomic_node_ptr& refHead, value_type& val, Func func, bool bInsert )
{
- position pos;
-
- rcu_lock l( bLock );
- while ( true ) {
- if ( search( refHead, val, pos, key_comparator() ) ) {
- assert( key_comparator()( val, *node_traits::to_value_ptr( *pos.pCur ) ) == 0 );
-
- func( false, *node_traits::to_value_ptr( *pos.pCur ), val );
- return std::make_pair( iterator( pos.pCur ), false );
- }
- else {
- link_checker::is_empty( node_traits::to_node_ptr( val ) );
-
- if ( link_node( node_traits::to_node_ptr( val ), pos ) ) {
- ++m_ItemCounter;
- func( true, val , val );
- return std::make_pair( iterator( node_traits::to_node_ptr( val )), true );
- }
-
- // clear the next field
- node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
- }
+ position pos( refHead );
+ {
+ rcu_lock l;
+ return update_at_locked( pos, val, func, bInsert );
}
}
template <typename Func>
- std::pair<bool, bool> ensure_at( atomic_node_ptr& refHead, value_type& val, Func func, bool bLock = true )
+ std::pair<bool, bool> update_at( atomic_node_ptr& refHead, value_type& val, Func func, bool bInsert )
{
- rcu_lock l( bLock );
- std::pair<iterator, bool> ret = ensure_at_( refHead, val, func, false );
- return std::make_pair( ret.first != end(), ret.second );
+ position pos( refHead );
+ {
+ rcu_lock l;
+ std::pair<iterator, bool> ret = update_at_locked( pos, val, func, bInsert );
+ return std::make_pair( ret.first != end(), ret.second );
+ }
}
bool unlink_at( atomic_node_ptr& refHead, value_type& val )
{
- position pos;
+ position pos( refHead );
back_off bkoff;
check_deadlock_policy::check();
for (;;) {
{
rcu_lock l;
- if ( !search( refHead, val, pos, key_comparator() ) || node_traits::to_value_ptr( *pos.pCur ) != &val )
+ if ( !search( refHead, val, pos, key_comparator() ) || node_traits::to_value_ptr( *pos.pCur ) != &val ) {
+ m_Stat.onEraseFailed();
return false;
- if ( !unlink_node( pos )) {
+ }
+ if ( !unlink_node( pos, erase_mask )) {
bkoff();
+ m_Stat.onEraseRetry();
continue;
}
}
--m_ItemCounter;
- dispose_node( pos.pCur );
+ m_Stat.onEraseSuccess();
return true;
}
}
template <typename Q, typename Compare, typename Func>
- bool erase_at( atomic_node_ptr& refHead, Q const& val, Compare cmp, Func f, position& pos )
+ bool erase_at( position& pos, Q const& val, Compare cmp, Func f )
{
back_off bkoff;
check_deadlock_policy::check();
+ node_type * pDel;
for (;;) {
{
rcu_lock l;
- if ( !search( refHead, val, pos, cmp ) )
+ if ( !search( pos.refHead, val, pos, cmp ) ) {
+ m_Stat.onEraseFailed();
return false;
- if ( !unlink_node( pos )) {
+ }
+
+ // store pCur since it may be changed by unlink_node() slow path
+ pDel = pos.pCur;
+ if ( !unlink_node( pos, erase_mask )) {
bkoff();
+ m_Stat.onEraseRetry();
continue;
}
}
-
- f( *node_traits::to_value_ptr( *pos.pCur ) );
+ assert( pDel );
+ f( *node_traits::to_value_ptr( pDel ) );
--m_ItemCounter;
- dispose_node( pos.pCur );
+ m_Stat.onEraseSuccess();
return true;
}
}
template <typename Q, typename Compare, typename Func>
bool erase_at( atomic_node_ptr& refHead, Q const& val, Compare cmp, Func f )
{
- position pos;
- return erase_at( refHead, val, cmp, f, pos );
+ position pos( refHead );
+ return erase_at( pos, val, cmp, f );
}
template <typename Q, typename Compare>
bool erase_at( atomic_node_ptr& refHead, const Q& val, Compare cmp )
{
- position pos;
- return erase_at( refHead, val, cmp, [](value_type const&){}, pos );
+ position pos( refHead );
+ return erase_at( pos, val, cmp, [](value_type const&){} );
}
template <typename Q, typename Compare >
value_type * extract_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
{
- position pos;
+ position pos( refHead );
back_off bkoff;
- assert( gc::is_locked() ) ; // RCU must be locked!!!
+ assert( !gc::is_locked() ) ; // RCU must not be locked!!!
- for (;;) {
- if ( !search( refHead, val, pos, cmp ) )
- return nullptr;
- if ( !unlink_node( pos )) {
- bkoff();
- continue;
- }
+ node_type * pExtracted;
+ {
+ rcu_lock l;
+ for (;;) {
+ if ( !search( refHead, val, pos, cmp )) {
+ m_Stat.onEraseFailed();
+ return nullptr;
+ }
- --m_ItemCounter;
- return node_traits::to_value_ptr( pos.pCur );
+ // store pCur since it may be changed by unlink_node() slow path
+ pExtracted = pos.pCur;
+ if ( !unlink_node( pos, extract_mask )) {
+ bkoff();
+ m_Stat.onEraseRetry();
+ continue;
+ }
+
+ --m_ItemCounter;
+ value_type * pRet = node_traits::to_value_ptr( pExtracted );
+ assert( pExtracted->m_pDelChain == nullptr );
+ m_Stat.onEraseSuccess();
+ return pRet;
+ }
}
}
template <typename Q, typename Compare, typename Func>
- bool find_at( atomic_node_ptr& refHead, Q& val, Compare cmp, Func f, bool bLock = true ) const
+ bool find_at( atomic_node_ptr& refHead, Q& val, Compare cmp, Func f )
{
- position pos;
+ position pos( refHead );
- rcu_lock l( bLock );
- if ( search( refHead, val, pos, cmp ) ) {
- assert( pos.pCur != nullptr );
- f( *node_traits::to_value_ptr( *pos.pCur ), val );
- return true;
- }
+ {
+ rcu_lock l;
+ if ( search( refHead, val, pos, cmp ) ) {
+ assert( pos.pCur != nullptr );
+ f( *node_traits::to_value_ptr( *pos.pCur ), val );
+ m_Stat.onFindSuccess();
+ return true;
+ }
+ }
+
+ m_Stat.onFindFailed();
return false;
}
template <typename Q, typename Compare>
- bool find_at( atomic_node_ptr& refHead, Q const& val, Compare cmp ) const
+ bool find_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
{
- rcu_lock l;
- return find_at_( refHead, val, cmp ) != end();
+ position pos( refHead );
+ {
+ rcu_lock l;
+ return find_at_locked( pos, val, cmp ) != cend();
+ }
}
template <typename Q, typename Compare>
- value_type * get_at( atomic_node_ptr& refHead, Q const& val, Compare cmp ) const
+ raw_ptr get_at( atomic_node_ptr& refHead, Q const& val, Compare cmp )
{
- value_type * pFound = nullptr;
- return find_at( refHead, val, cmp,
- [&pFound](value_type& found, Q const& ) { pFound = &found; } )
- ? pFound : nullptr;
- }
+ // RCU should be locked!
+ assert(gc::is_locked() );
- template <typename Q, typename Compare>
- const_iterator find_at_( atomic_node_ptr& refHead, Q const& val, Compare cmp ) const
- {
- assert( gc::is_locked() );
- position pos;
+ position pos( refHead );
- if ( search( refHead, val, pos, cmp ) ) {
- assert( pos.pCur != nullptr );
- return const_iterator( pos.pCur );
+ if ( search( refHead, val, pos, cmp )) {
+ m_Stat.onFindSuccess();
+ return raw_ptr( node_traits::to_value_ptr( pos.pCur ), raw_ptr_disposer( pos ));
}
- return end();
- }
+ m_Stat.onFindFailed();
+ return raw_ptr( raw_ptr_disposer( pos ));
+ }
//@endcond
protected:
//@cond
template <typename Q, typename Compare>
- bool search( atomic_node_ptr& refHead, const Q& val, position& pos, Compare cmp ) const
+ bool search( atomic_node_ptr& refHead, const Q& val, position& pos, Compare cmp )
{
// RCU lock should be locked!!!
assert( gc::is_locked() );
while ( true ) {
if ( !pCur.ptr() ) {
pos.pPrev = pPrev;
- pos.pCur = pCur.ptr();
- pos.pNext = pNext.ptr();
+ pos.pCur = nullptr;
+ pos.pNext = nullptr;
return false;
}
- pNext = pCur->m_pNext.load(memory_model::memory_order_relaxed);
+ pNext = pCur->m_pNext.load(memory_model::memory_order_acquire);
- if ( pPrev->load(memory_model::memory_order_acquire) != pCur
- || pNext != pCur->m_pNext.load(memory_model::memory_order_acquire)
- || pNext.bits() != 0 ) // pNext contains deletion mark for pCur
+ if ( cds_unlikely( pPrev->load(memory_model::memory_order_acquire) != pCur
+ || pNext != pCur->m_pNext.load(memory_model::memory_order_acquire )))
{
- // if pCur is marked as deleted (pNext.bits() != 0)
- // we wait for physical removal.
- // Helping technique is not suitable for RCU since it requires
- // that the RCU should be in unlocking state.
bkoff();
goto try_again;
}
+ if ( pNext.bits() ) {
+ // pCur is marked as deleted. Try to unlink it from the list
+ if ( cds_likely( pPrev->compare_exchange_weak( pCur, marked_node_ptr( pNext.ptr() ), memory_model::memory_order_acquire, atomics::memory_order_relaxed ))) {
+ if ( pNext.bits() == erase_mask )
+ link_to_remove_chain( pos, pCur.ptr() );
+ m_Stat.onHelpingSuccess();
+ }
+
+ m_Stat.onHelpingFailed();
+ goto try_again;
+ }
+
assert( pCur.ptr() != nullptr );
int nCmp = cmp( *node_traits::to_value_ptr( pCur.ptr() ), val );
if ( nCmp >= 0 ) {
}
}
//@endcond
+
+ private:
+ //@cond
+ bool insert_at_locked( position& pos, value_type& val )
+ {
+ // RCU lock should be locked!!!
+ assert( gc::is_locked() );
+
+ while ( true ) {
+ if ( search( pos.refHead, val, pos, key_comparator() )) {
+ m_Stat.onInsertFailed();
+ return false;
+ }
+
+ if ( link_node( node_traits::to_node_ptr( val ), pos ) ) {
+ ++m_ItemCounter;
+ m_Stat.onInsertSuccess();
+ return true;
+ }
+
+ // clear next field
+ node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
+ m_Stat.onInsertRetry();
+ }
+ }
+
+ template <typename Func>
+ std::pair<iterator, bool> update_at_locked( position& pos, value_type& val, Func func, bool bInsert )
+ {
+ // RCU should be locked!!!
+ assert( gc::is_locked() );
+
+ while ( true ) {
+ if ( search( pos.refHead, val, pos, key_comparator() ) ) {
+ assert( key_comparator()( val, *node_traits::to_value_ptr( *pos.pCur ) ) == 0 );
+
+ func( false, *node_traits::to_value_ptr( *pos.pCur ), val );
+ m_Stat.onUpdateExisting();
+ return std::make_pair( iterator( pos.pCur ), false );
+ }
+ else {
+ if ( !bInsert ) {
+ m_Stat.onUpdateFailed();
+ return std::make_pair( end(), false );
+ }
+
+ if ( link_node( node_traits::to_node_ptr( val ), pos ) ) {
+ ++m_ItemCounter;
+ func( true, val , val );
+ m_Stat.onUpdateNew();
+ return std::make_pair( iterator( node_traits::to_node_ptr( val )), true );
+ }
+
+ // clear the next field
+ node_traits::to_node_ptr( val )->m_pNext.store( marked_node_ptr(), memory_model::memory_order_relaxed );
+ m_Stat.onUpdateRetry();
+ }
+ }
+ }
+
+ template <typename Q, typename Compare>
+ const_iterator find_at_locked( position& pos, Q const& val, Compare cmp )
+ {
+ assert( gc::is_locked() );
+
+ if ( search( pos.refHead, val, pos, cmp ) ) {
+ assert( pos.pCur != nullptr );
+ m_Stat.onFindSuccess();
+ return const_iterator( pos.pCur );
+ }
+
+ m_Stat.onFindFailed();
+ return cend();
+ }
+ //@endcond
};
}} // namespace cds::intrusive
projects / libcds.git / blobdiff