-//$$CDS-header$$
+/*
+ This file is a part of libcds - Concurrent Data Structures library
-#ifndef __CDS_INTRUSIVE_SPLIT_LIST_RCU_H
-#define __CDS_INTRUSIVE_SPLIT_LIST_RCU_H
+ (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_SPLIT_LIST_RCU_H
+#define CDSLIB_INTRUSIVE_SPLIT_LIST_RCU_H
+
+#include <limits>
#include <cds/intrusive/details/split_list_base.h>
#include <cds/details/binary_functor_wrapper.h>
- \p Traits - set traits, default isd \p split_list::traits.
Instead of defining \p Traits struct you may use option-based syntax with \p split_list::make_traits metafunction.
- @note About reqired features of hash functor see \ref cds_SplitList_hash_functor "SplitList general description".
+ @note About required features of hash functor see \ref cds_SplitList_hash_functor "SplitList general description".
\par How to use
Before including <tt><cds/intrusive/split_list_rcu.h></tt> you should include appropriate RCU header file,
typedef typename ordered_list::disposer disposer; ///< Node disposer functor
typedef typename ordered_list::rcu_lock rcu_lock; ///< RCU scoped lock
typedef typename ordered_list::exempt_ptr exempt_ptr; ///< pointer to extracted node
+ typedef typename ordered_list::raw_ptr raw_ptr; ///< pointer to the node for \p get() function
/// Group of \p extract_xxx functions require external locking if underlying ordered list requires that
static CDS_CONSTEXPR const bool c_bExtractLockExternal = ordered_list::c_bExtractLockExternal;
class ordered_list_wrapper: public ordered_list
{
typedef ordered_list base_class;
- typedef typename base_class::auxiliary_head bucket_head_type;
+ typedef typename base_class::auxiliary_head bucket_head_type;
public:
bool insert_at( dummy_node_type * pHead, value_type& val )
}
template <typename Func>
- std::pair<bool, bool> ensure_at( dummy_node_type * pHead, value_type& val, Func func )
+ std::pair<bool, bool> update_at( dummy_node_type * pHead, value_type& val, Func func, bool bAllowInsert )
{
assert( pHead != nullptr );
bucket_head_type h(pHead);
- return base_class::ensure_at( h, val, func );
+ return base_class::update_at( h, val, func, bAllowInsert );
}
bool unlink_at( dummy_node_type * pHead, value_type& val )
}
template <typename Q, typename Compare, typename Func>
- bool find_at( dummy_node_type * pHead, split_list::details::search_value_type<Q>& val, Compare cmp, Func f ) const
+ bool find_at( dummy_node_type * pHead, split_list::details::search_value_type<Q>& val, Compare cmp, Func f )
{
assert( pHead != nullptr );
bucket_head_type h(pHead);
}
template <typename Q, typename Compare>
- bool find_at( dummy_node_type * pHead, split_list::details::search_value_type<Q> const & val, Compare cmp ) const
+ bool find_at( dummy_node_type * pHead, split_list::details::search_value_type<Q> const & val, Compare cmp )
{
assert( pHead != nullptr );
bucket_head_type h(pHead);
}
template <typename Q, typename Compare>
- value_type * get_at( dummy_node_type * pHead, split_list::details::search_value_type<Q>& val, Compare cmp ) const
+ raw_ptr get_at( dummy_node_type * pHead, split_list::details::search_value_type<Q>& val, Compare cmp )
{
assert( pHead != nullptr );
bucket_head_type h(pHead);
ordered_list_wrapper m_List; ///< Ordered list containing split-list items
bucket_table m_Buckets; ///< bucket table
atomics::atomic<size_t> m_nBucketCountLog2; ///< log2( current bucket count )
+ atomics::atomic<size_t> m_nMaxItemCount; ///< number of items container can hold, before we have to resize
item_counter m_ItemCounter; ///< Item counter
hash m_HashFunctor; ///< Hash functor
- stat m_Stat; ///< Internal stattistics accumulator
+ stat m_Stat; ///< Internal statistics accumulator
protected:
//@cond
size_t bucket_no( size_t nHash ) const
{
- return nHash & ( (1 << m_nBucketCountLog2.load(atomics::memory_order_relaxed)) - 1 );
+ return nHash & ( (1 << m_nBucketCountLog2.load(memory_model::memory_order_relaxed)) - 1 );
}
static size_t parent_bucket( size_t nBucket )
m_Buckets.bucket( 0, pNode );
}
- void inc_item_count()
+ static size_t max_item_count( size_t nBucketCount, size_t nLoadFactor )
{
- size_t sz = m_nBucketCountLog2.load(atomics::memory_order_relaxed);
- if ( ( ++m_ItemCounter >> sz ) > m_Buckets.load_factor() && ((size_t)(1 << sz )) < m_Buckets.capacity() )
- {
- m_nBucketCountLog2.compare_exchange_strong( sz, sz + 1, atomics::memory_order_seq_cst, atomics::memory_order_relaxed );
+ return nBucketCount * nLoadFactor;
+ }
+
+ void inc_item_count()
+ {
+ size_t nMaxCount = m_nMaxItemCount.load(memory_model::memory_order_relaxed);
+ if ( ++m_ItemCounter <= nMaxCount )
+ return;
+
+ size_t sz = m_nBucketCountLog2.load(memory_model::memory_order_relaxed);
+ const size_t nBucketCount = static_cast<size_t>(1) << sz;
+ if ( nBucketCount < m_Buckets.capacity() ) {
+ // we may grow the bucket table
+ const size_t nLoadFactor = m_Buckets.load_factor();
+ if ( nMaxCount < max_item_count( nBucketCount, nLoadFactor ))
+ return; // someone already have updated m_nBucketCountLog2, so stop here
+
+ m_nMaxItemCount.compare_exchange_strong( nMaxCount, max_item_count( nBucketCount << 1, nLoadFactor ),
+ memory_model::memory_order_relaxed, atomics::memory_order_relaxed );
+ m_nBucketCountLog2.compare_exchange_strong( sz, sz + 1, memory_model::memory_order_relaxed, atomics::memory_order_relaxed );
}
+ else
+ m_nMaxItemCount.store( std::numeric_limits<size_t>::max(), memory_model::memory_order_relaxed );
}
template <typename Q, typename Compare, typename Func>
}
template <typename Q, typename Compare>
- value_type * get_( Q const& val, Compare cmp )
+ raw_ptr get_( Q const& val, Compare cmp )
{
size_t nHash = hash_value( val );
split_list::details::search_value_type<Q const> sv( val, split_list::regular_hash( nHash ));
dummy_node_type * pHead = get_bucket( nHash );
assert( pHead != nullptr );
- value_type * p = m_List.get_at( pHead, sv, cmp );
- m_Stat.onFind( p != nullptr );
+ raw_ptr p = m_List.get_at( pHead, sv, cmp );
+ m_Stat.onFind( !!p );
return p;
}
template <typename Q, typename Less>
value_type * extract_with_( Q const& val, Less pred )
{
+ CDS_UNUSED( pred );
return extract_( val, typename wrapped_ordered_list::template make_compare_from_less<Less>());
}
*/
SplitListSet()
: m_nBucketCountLog2(1)
+ , m_nMaxItemCount( max_item_count(2, m_Buckets.load_factor()) )
{
init();
}
)
: m_Buckets( nItemCount, nLoadFactor )
, m_nBucketCountLog2(1)
+ , m_nMaxItemCount( max_item_count(2, m_Buckets.load_factor()) )
{
init();
}
return false;
}
- /// Ensures that the \p val exists in the set
+ /// Updates the node
/**
The operation performs inserting or changing data with lock-free manner.
- If the item \p val is not found in the set, then \p val is inserted into the set.
+ If the item \p val is not found in the set, then \p val is inserted
+ 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 set
- - \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
- refers to the same thing.
+ refers to the same stuff.
- The function makes RCU lock internally.
+ The functor may change non-key fields of the \p item.
+
+ The function applies RCU lock internally.
Returns std::pair<bool, bool> where \p first is \p true if operation is successfull,
\p second is \p true if new item has been added or \p false if the item with \p key
- already is in the set.
+ already is in the list.
@warning For \ref cds_intrusive_MichaelList_rcu "MichaelList" as the bucket see \ref cds_intrusive_item_creating "insert item troubleshooting".
\ref cds_intrusive_LazyList_rcu "LazyList" provides exclusive access to inserted item and does not require any node-level
synchronization.
- */
+ */
template <typename Func>
- std::pair<bool, bool> ensure( value_type& val, Func func )
+ std::pair<bool, bool> update( value_type& val, Func func, bool bAllowInsert = true )
{
size_t nHash = hash_value( val );
dummy_node_type * pHead = get_bucket( nHash );
node_traits::to_node_ptr( val )->m_nHash = split_list::regular_hash( nHash );
- std::pair<bool, bool> bRet = m_List.ensure_at( pHead, val, func );
+ std::pair<bool, bool> bRet = m_List.update_at( pHead, val, func, bAllowInsert );
if ( bRet.first && bRet.second ) {
inc_item_count();
- m_Stat.onEnsureNew();
+ m_Stat.onUpdateNew();
}
else
- m_Stat.onEnsureExist();
+ m_Stat.onUpdateExist();
return bRet;
}
+ //@cond
+ template <typename Func>
+ CDS_DEPRECATED("ensure() is deprecated, use update()")
+ std::pair<bool, bool> ensure( value_type& val, Func func )
+ {
+ return update( val, func, true );
+ }
+ //@endcond
/// Unlinks the item \p val from the set
/**
template <typename Q, typename Less>
bool erase_with( Q const& key, Less pred )
{
+ CDS_UNUSED( pred );
return erase_( key, typename wrapped_ordered_list::template make_compare_from_less<Less>() );
}
void operator()( value_type const& item );
};
\endcode
- The functor can be passed by reference with <tt>boost:ref</tt>
If the item with key equal to \p key is not found the function return \p false.
template <typename Q, typename Less, typename Func>
bool erase_with( Q const& key, Less pred, Func f )
{
+ CDS_UNUSED( pred );
return erase_( key, typename wrapped_ordered_list::template make_compare_from_less<Less>(), f );
}
/// Extracts an item from the set
/** \anchor cds_intrusive_SplitListSet_rcu_extract
The function searches an item with key equal to \p key in the set,
- unlinks it, and returns pointer to an item found in \p dest argument.
- If the item with the key equal to \p key is not found the function returns \p false.
+ unlinks it, and returns \ref cds::urcu::exempt_ptr "exempt_ptr" pointer to the item found.
+ If the item with the key equal to \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 excludes the item from the set
- and returns a pointer to item found.
- You should lock RCU before calling of the function, and you should synchronize RCU
- outside the RCU lock before reusing returned pointer.
+ Depends on \p bucket_type you should or should not lock RCU before calling of this function:
+ - for the set based on \ref cds_intrusive_MichaelList_rcu "MichaelList" RCU should not be locked
+ - for the set based on \ref cds_intrusive_LazyList_rcu "LazyList" RCU should be locked
+ See ordered list implementation for details.
\code
typedef cds::urcu::gc< general_buffered<> > rcu;
// ...
rcu_splitlist_set::exempt_ptr p;
- {
- // first, we should lock RCU
- rcu_splitlist_set::rcu_lock lock;
-
- // Now, you can apply extract function
- // Note that you must not delete the item found inside the RCU lock
- if ( theList.extract( p, 10 )) {
- // do something with p
- ...
- }
+
+ // For MichaelList we should not lock RCU
+
+ // Now, you can apply extract function
+ // Note that you must not delete the item found inside the RCU lock
+ p = theList.extract( 10 );
+ if ( p ) {
+ // do something with p
+ ...
}
// We may safely release p here
\endcode
*/
template <typename Q>
- bool extract( exempt_ptr& dest, Q const& key )
+ exempt_ptr extract( Q const& key )
{
- value_type * pNode = extract_( key, key_comparator() );
- if ( pNode ) {
- dest = pNode;
- return true;
- }
- return false;
+ return exempt_ptr(extract_( key, key_comparator() ));
}
/// Extracts an item from the set using \p pred for searching
/**
- The function is an analog of \ref cds_intrusive_SplitListSet_rcu_extract "extract(exempt_ptr&, Q const&)"
- but \p pred is used for key compare.
+ The function is an analog of \p extract(Q const&) but \p pred is used for key compare.
\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 set.
*/
template <typename Q, typename Less>
- bool extract_with( exempt_ptr& dest, Q const& key, Less pred )
+ exempt_ptr extract_with( Q const& key, Less pred )
{
- value_type * pNode = extract_with_( key, pred );
- if ( pNode ) {
- dest = pNode;
- return true;
- }
- return false;
+ return exempt_ptr( extract_with_( key, pred ));
}
/// Finds the key \p key
\endcode
where \p item is the item found, \p key is the <tt>find</tt> function argument.
- You can pass \p f argument by value or by reference using \p std::ref.
-
The functor can change non-key fields of \p item. Note that the functor is only guarantee
that \p item cannot be disposed during functor is executing.
The functor does not serialize simultaneous access to the set \p item. If such access is
{
return find_( key, key_comparator(), f );
}
+ //@cond
+ template <typename Q, typename Func>
+ bool find( Q const& key, Func f )
+ {
+ return find_( key, key_comparator(), f );
+ }
+ //@endcond
/// Finds the key \p key with \p pred predicate for comparing
/**
template <typename Q, typename Less, typename Func>
bool find_with( Q& key, Less pred, Func f )
{
+ CDS_UNUSED( pred );
return find_( key, typename wrapped_ordered_list::template make_compare_from_less<Less>(), f );
}
+ //@cond
+ template <typename Q, typename Less, typename Func>
+ bool find_with( Q const& key, Less pred, Func f )
+ {
+ CDS_UNUSED( pred );
+ return find_( key, typename wrapped_ordered_list::template make_compare_from_less<Less>(), f );
+ }
+ //@endcond
-
- /// Finds the key \p key
- /** \anchor cds_intrusive_SplitListSet_rcu_find_val
+ /// Checks whether the set contains \p key
+ /**
The function searches the item with key equal to \p key
- and returns \p true if \p key found or \p false otherwise.
+ and returns \p true if it is found, and \p false otherwise.
+
+ Note the hash functor specified for class \p Traits template parameter
+ should accept a parameter of type \p Q that can be not the same as \p value_type.
+ Otherwise, you may use \p contains( Q const&, Less pred ) functions with explicit predicate for key comparing.
*/
template <typename Q>
- bool find( Q const& key )
+ bool contains( Q const& key )
{
return find_value( key, key_comparator() );
}
+ //@cond
+ template <typename Q>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find( Q const& key )
+ {
+ return contains( key );
+ }
+ //@endcond
- /// Finds the key \p key with \p pred predicate for comparing
+ /// Checks whether the set contains \p key using \p pred predicate for searching
/**
- The function is an analog of \ref cds_intrusive_SplitListSet_rcu_find_val "find(Q const&)"
- but \p cmp is used for key compare.
- \p Less has the interface like \p std::less.
- \p pred must imply the same element order as the comparator used for building the set.
+ 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 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 )
+ bool contains( Q const& key, Less pred )
{
+ CDS_UNUSED( pred );
return find_value( key, typename wrapped_ordered_list::template make_compare_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 the key \p key and return the item found
/** \anchor cds_intrusive_SplitListSet_rcu_get
RCU should be locked before call of this function.
Returned item is valid only while RCU is locked:
\code
- cds::intrusive::SplitListSet< your_template_parameters > theSet;
+ typedef cds::intrusive::SplitListSet< your_template_parameters > set_class;
+ set_class theSet;
// ...
+ typename set_class::raw_ptr rp;
{
// Lock RCU
hash_set::rcu_lock lock;
- foo * pVal = theSet.get( 5 );
- if ( pVal ) {
- // Deal with pVal
+ rp = theSet.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
+ // rp can be retired by disposer at any time after RCU has been unlocked
}
\endcode
*/
template <typename Q>
- value_type * get( Q const& key )
+ raw_ptr get( Q const& key )
{
return get_( key, key_comparator() );
}
\p pred must imply the same element order as the comparator used for building the set.
*/
template <typename Q, typename Less>
- value_type * get_with( Q const& key, Less pred )
+ raw_ptr get_with( Q const& key, Less pred )
{
+ CDS_UNUSED( pred );
return get_( key, typename wrapped_ordered_list::template make_compare_from_less<Less>());
}
{}
};
//@endcond
+
public:
+ ///@name Forward iterators (thread-safe under RCU lock)
+ //@{
/// Forward iterator
/**
The forward iterator for a split-list has some features:
- it has no post-increment operator
- it depends on iterator of underlying \p OrderedList
- - The iterator cannot be moved across thread boundary since it may contain GC's guard that is thread-private GC data.
- - Iterator ensures thread-safety even if you delete the item that iterator points to. However, in case of concurrent
- deleting operations it is no guarantee that you iterate all item in the split-list.
- Therefore, the use of iterators in concurrent environment is not good idea. Use the iterator on the concurrent container
- for debug purpose only.
+ You may safely use iterators in multi-threaded environment only under RCU lock.
+ Otherwise, a crash is possible if another thread deletes the element the iterator points to.
*/
typedef iterator_type<false> iterator;
+
/// Const forward iterator
/**
For iterator's features and requirements see \ref iterator
{
return const_iterator( m_List.cend(), m_List.cend() );
}
-
+ //@}
};
}} // namespace cds::intrusive
-#endif // #ifndef __CDS_INTRUSIVE_SPLIT_LIST_RCU_H
+#endif // #ifndef CDSLIB_INTRUSIVE_SPLIT_LIST_RCU_H
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