//$$CDS-header$$
-#ifndef __CDS_INTRUSIVE_IMPL_ELLEN_BINTREE_H
-#define __CDS_INTRUSIVE_IMPL_ELLEN_BINTREE_H
+#ifndef CDSLIB_INTRUSIVE_IMPL_ELLEN_BINTREE_H
+#define CDSLIB_INTRUSIVE_IMPL_ELLEN_BINTREE_H
#include <memory>
#include <cds/intrusive/details/ellen_bintree_base.h>
#include <cds/opt/compare.h>
#include <cds/details/binary_functor_wrapper.h>
#include <cds/urcu/details/check_deadlock.h>
-#include <cds/gc/guarded_ptr.h>
namespace cds { namespace intrusive {
the priority value plus some uniformly distributed random value.
@note In the current implementation we do not use helping technique described in the original paper.
- In Hazard Pointer schema helping is too complicated and does not give any observable benefits.
+ In Hazard Pointer schema the helping is too complicated and does not give any observable benefits.
Instead of helping, when a thread encounters a concurrent operation it just spins waiting for
- the operation done. Such solution allows greatly simplify the implementation of tree.
+ the operation done. Such solution allows greatly simplify implementation of the tree.
- @warning Recall the tree is <b>unbalanced</b>. The complexity of operations is <tt>O(log N)</tt>
+ @attention Recall the tree is <b>unbalanced</b>. The complexity of operations is <tt>O(log N)</tt>
for uniformly distributed random keys, but in worst case the complexity is <tt>O(N)</tt>.
@note Do not include <tt><cds/intrusive/impl/ellen_bintree.h></tt> header file explicitly.
typedef typename traits::disposer disposer; ///< leaf node disposer
typedef typename traits::back_off back_off; ///< back-off strategy
- typedef cds::gc::guarded_ptr< gc, value_type > guarded_ptr; ///< Guarded pointer
+ typedef typename gc::template guarded_ptr< value_type > guarded_ptr; ///< Guarded pointer
protected:
//@cond
typedef typename traits::node_allocator node_allocator; ///< Allocator for internal node
typedef typename traits::update_desc_allocator update_desc_allocator; ///< Update descriptor allocator
+ static CDS_CONSTEXPR const size_t c_nHazardPtrCount = 9; ///< Count of hazard pointer required for the algorithm
+
protected:
//@cond
typedef ellen_bintree::details::compare< key_type, value_type, key_comparator, node_traits > node_compare;
Guard_Leaf,
Guard_updGrandParent,
Guard_updParent,
-
- // helping
- Guard_helpLeaf,
+ Guard_temporary,
// end of guard indices
guard_count
,bRightLeaf( false )
,bRightParent( false )
{}
-
- void clean_help_guards()
- {
- guards.clear( Guard_helpLeaf );
- }
};
//@endcond
return true;
}
- /// Ensures that the \p val exists in the tree
+ /// Updates the node
/**
The operation performs inserting or changing data with lock-free manner.
- If the item \p val is not found in the tree, then \p val is inserted into the tree.
+ If the item \p val is not found in the set, then \p val is inserted into the set
+ iff \p bAllowInsert is \p true.
Otherwise, the functor \p func is called with item found.
- The functor signature is:
+ The functor \p func signature is:
\code
void func( bool bNew, value_type& item, value_type& val );
\endcode
with arguments:
- \p bNew - \p true if the item has been inserted, \p false otherwise
- - \p item - an item of the tree
- - \p val - the argument \p val passed to the \p ensure function
+ - \p item - item of the set
+ - \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.
that during changing no any other modifications could be made on this item by concurrent threads.
Returns std::pair<bool, bool> where \p first is \p true if operation is successfull,
+ i.e. the node has been inserted or updated,
\p second is \p true if new item has been added or \p false if the item with \p key
- already is in the tree.
+ already exists.
@warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
*/
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 )
{
typename gc::Guard guardInsert;
guardInsert.assign( &val );
}
if ( res.updGrandParent.bits() == update_desc::Clean && res.updParent.bits() == update_desc::Clean ) {
+ if ( !bAllowInsert )
+ return std::make_pair( false, false );
if ( !pNewInternal.get() )
pNewInternal.reset( alloc_internal_node() );
m_Stat.onEnsureNew();
return std::make_pair( true, true );
}
+ //@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 tree
/**
template <typename Q, typename Less>
bool erase_with( const Q& key, Less pred )
{
+ CDS_UNUSED( pred );
typedef ellen_bintree::details::compare<
key_type,
value_type,
template <typename Q, typename Less, typename Func>
bool erase_with( Q const& key, Less pred, Func f )
{
+ CDS_UNUSED( pred );
typedef ellen_bintree::details::compare<
key_type,
value_type,
/// Extracts an item with minimal key from the tree
/**
- The function searches an item with minimal key, unlinks it, and returns pointer to an item found in \p dest parameter.
- If the tree is empty the function returns \p false.
+ The function searches an item with minimal key, unlinks it, and returns a guarded pointer to an item found.
+ If the tree is empty the function returns an empty guarded pointer.
@note Due the concurrent nature of the tree, the function extracts <i>nearly</i> minimum key.
It means that the function gets leftmost leaf of the tree and tries to unlink it.
During unlinking, a concurrent thread may insert an item with key less than leftmost item's key.
So, the function returns the item with minimum key at the moment of tree traversing.
- The guarded pointer \p dest prevents disposer invocation for returned item,
- see cds::gc::guarded_ptr for explanation.
+ The returned \p guarded_ptr prevents disposer invocation for returned item,
+ see \p cds::gc::guarded_ptr for explanation.
@note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
*/
- bool extract_min( guarded_ptr& dest )
+ guarded_ptr extract_min()
{
- return extract_min_( dest.guard());
+ guarded_ptr gp;
+ extract_min_( gp.guard() );
+ return gp;
}
/// Extracts an item with maximal key from the tree
/**
- The function searches an item with maximal key, unlinks it, and returns pointer to an item found in \p dest parameter.
- If the tree is empty the function returns \p false.
+ The function searches an item with maximal key, unlinks it, and returns a guarded pointer to an item found.
+ If the tree is empty the function returns an empty \p guarded_ptr.
@note Due the concurrent nature of the tree, the function extracts <i>nearly</i> maximal key.
It means that the function gets rightmost leaf of the tree and tries to unlink it.
During unlinking, a concurrent thread may insert an item with key great than rightmost item's key.
So, the function returns the item with maximal key at the moment of tree traversing.
- The guarded pointer \p dest prevents disposer invocation for returned item,
+ The returned \p guarded_ptr prevents disposer invocation for returned item,
see cds::gc::guarded_ptr for explanation.
@note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
*/
- bool extract_max( guarded_ptr& dest )
+ guarded_ptr extract_max()
{
- return extract_max_( dest.guard() );
+ guarded_ptr gp;
+ extract_max_( gp.guard());
+ return gp;
}
/// Extracts an item from the tree
/** \anchor cds_intrusive_EllenBinTree_extract
The function searches an item with key equal to \p key in the tree,
- unlinks it, and returns pointer to an item found in \p dest parameter.
- If the item is not found the function returns \p false.
+ unlinks it, and returns a guarded pointer to an item found.
+ If the item is not found the function returns an empty \p guarded_ptr.
- The guarded pointer \p dest prevents disposer invocation for returned item,
+ \p guarded_ptr prevents disposer invocation for returned item,
see cds::gc::guarded_ptr for explanation.
@note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
*/
template <typename Q>
- bool extract( guarded_ptr& dest, Q const& key )
+ guarded_ptr extract( Q const& key )
{
- return extract_( dest.guard(), key );
+ guarded_ptr gp;
+ extract_( gp.guard(), key );
+ return gp;
}
/// Extracts an item from the tree using \p pred for searching
/**
- The function is an analog of \ref cds_intrusive_EllenBinTree_extract "extract(guarded_ptr& dest, Q const&)"
+ The function is an analog of \ref cds_intrusive_EllenBinTree_extract "extract(Q const&)"
but \p pred is used for key compare.
\p Less has the interface like \p std::less and should meet \ref cds_intrusive_EllenBinTree_less
"Predicate requirements".
\p pred must imply the same element order as the comparator used for building the tree.
*/
template <typename Q, typename Less>
- bool extract_with( guarded_ptr& dest, Q const& key, Less pred )
+ guarded_ptr extract_with( Q const& key, Less pred )
{
- return extract_with_( dest.guard(), key, pred );
+ guarded_ptr gp;
+ extract_with_( gp.guard(), key, pred );
+ return gp;
}
- /// Finds the key \p key
- /** @anchor cds_intrusive_EllenBinTree_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 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.
*/
template <typename Q>
- bool find( Q const& key ) const
+ bool contains( Q const& key ) const
{
search_result res;
if ( search( res, key, node_compare() )) {
m_Stat.onFindFailed();
return false;
}
+ //@cond
+ template <typename Q>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find( Q const& key ) const
+ {
+ return contains( key );
+ }
+ //@endcond
- /// Finds the key \p key with comparing functor \p pred
+ /// Checks whether the set contains \p key using \p pred predicate for searching
/**
- The function is an analog of \ref cds_intrusive_EllenBinTree_find_val "find(Q const&)"
- but \p pred is used for key compare.
- \p Less functor has the interface like \p std::less and should meet \ref cds_intrusive_EllenBinTree_less
- "Predicate requirements".
- \p pred must imply the same element order as the comparator used for building the tree.
- \p pred should accept arguments of type \p Q, \p key_type, \p value_type in any combination.
+ The function is similar to <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 set.
*/
template <typename Q, typename Less>
- bool find_with( Q const& key, Less pred ) const
+ bool contains( Q const& key, Less pred ) const
{
+ CDS_UNUSED( pred );
typedef ellen_bintree::details::compare<
key_type,
value_type,
m_Stat.onFindFailed();
return false;
}
+ //@cond
+ template <typename Q, typename Less>
+ CDS_DEPRECATED("deprecated, use contains()")
+ bool find_with( Q const& key, Less pred ) const
+ {
+ return contains( key, pred );
+ }
+ //@endcond
/// Finds the key \p key
/** @anchor cds_intrusive_EllenBinTree_find_func
/// Finds \p key and returns the item found
/** @anchor cds_intrusive_EllenBinTree_get
- The function searches the item with key equal to \p key and returns the item found in \p dest parameter.
- The function returns \p true if \p key is found, \p false otherwise.
+ The function searches the item with key equal to \p key and returns the item found as \p guarded_ptr object.
+ The function returns an empty guarded pointer is \p key is not found.
- The guarded pointer \p dest prevents disposer invocation for returned item,
- see cds::gc::guarded_ptr for explanation.
+ \p guarded_ptr prevents disposer invocation for returned item,
+ see \p cds::gc::guarded_ptr for explanation.
@note Each \p guarded_ptr object uses the GC's guard that can be limited resource.
*/
template <typename Q>
- bool get( guarded_ptr& dest, Q const& key ) const
+ guarded_ptr get( Q const& key ) const
{
- return get_( dest.guard(), key );
+ guarded_ptr gp;
+ get_( gp.guard(), key );
+ return gp;
}
/// Finds \p key with predicate \p pred and returns the item found
/**
- The function is an analog of \ref cds_intrusive_EllenBinTree_get "get(guarded_ptr&, Q const&)"
+ The function is an analog of \ref cds_intrusive_EllenBinTree_get "get(Q const&)"
but \p pred is used for key comparing.
\p Less functor has the interface like \p std::less and should meet \ref cds_intrusive_EllenBinTree_less
"Predicate requirements".
\p pred must imply the same element order as the comparator used for building the tree.
*/
template <typename Q, typename Less>
- bool get_with( guarded_ptr& dest, Q const& key, Less pred ) const
+ guarded_ptr get_with( Q const& key, Less pred ) const
{
- return get_with_( dest.guard(), key, pred );
+ guarded_ptr gp;
+ get_with_( gp.guard(), key, pred );
+ return gp;
}
/// Checks if the tree is empty
void clear()
{
guarded_ptr gp;
- while ( extract_min(gp));
+ do {
+ gp = extract_min();
+ } while ( gp );
}
/// Clears the tree (not thread safe)
tree_node * protect_child_node( search_result& res, internal_node * pParent, bool bRight, update_ptr updParent ) const
{
- tree_node * p;
- tree_node * pn = bRight ? pParent->m_pRight.load( memory_model::memory_order_relaxed ) : pParent->m_pLeft.load( memory_model::memory_order_relaxed );
- do {
- p = pn;
- res.guards.assign( search_result::Guard_Leaf, static_cast<internal_node *>( p ));
- res.guards.assign( search_result::Guard_helpLeaf, node_traits::to_value_ptr( static_cast<leaf_node *>( p ) ));
- pn = bRight ? pParent->m_pRight.load( memory_model::memory_order_acquire ) : pParent->m_pLeft.load( memory_model::memory_order_acquire );
- } while ( p != pn );
+ retry:
+ tree_node * p = bRight
+ ? res.guards.protect( search_result::Guard_Leaf, pParent->m_pRight,
+ []( tree_node * p ) -> internal_node* { return static_cast<internal_node *>(p);})
+ : res.guards.protect( search_result::Guard_Leaf, pParent->m_pLeft,
+ []( tree_node * p ) -> internal_node* { return static_cast<internal_node *>(p);});
+
+ // If we use member hook, data node pointer != internal node pointer
+ // So, we need protect the child twice: as internal node and as data node
+ // and then analyze what kind of node we have
+ tree_node * pVal = bRight
+ ? res.guards.protect( search_result::Guard_temporary, pParent->m_pRight,
+ []( tree_node * p ) -> value_type* { return node_traits::to_value_ptr( static_cast<leaf_node *>(p));} )
+ : res.guards.protect( search_result::Guard_temporary, pParent->m_pLeft,
+ []( tree_node * p ) -> value_type* { return node_traits::to_value_ptr( static_cast<leaf_node *>(p));} );
// child node is guarded
// See whether pParent->m_pUpdate has not been changed
return nullptr;
}
- if ( p && p->is_leaf() )
- res.guards.copy( search_result::Guard_Leaf, search_result::Guard_helpLeaf );
- res.guards.clear( search_result::Guard_helpLeaf );
+ if ( p != pVal )
+ goto retry;
+
+ if ( p && p->is_leaf())
+ res.guards.assign( search_result::Guard_Leaf, node_traits::to_value_ptr( static_cast<leaf_node *>( p )));
+
+ res.guards.clear( search_result::Guard_temporary );
+
return p;
}
- update_ptr search_protect_update( search_result& res, atomics::atomic<update_ptr> const& src ) const
+ static update_ptr search_protect_update( search_result& res, atomics::atomic<update_ptr> const& src )
{
- update_ptr ret;
- update_ptr upd( src.load( memory_model::memory_order_relaxed ) );
- do {
- ret = upd;
- res.guards.assign( search_result::Guard_updParent, upd );
- } while ( ret != (upd = src.load( memory_model::memory_order_acquire )) );
- return ret;
+ return res.guards.protect( search_result::Guard_updParent, src, [](update_ptr p) -> update_desc* { return p.ptr(); });
}
template <typename KeyValue, typename Compare>
assert( res.pGrandParent != nullptr );
- return
- static_cast<internal_node *>(
- res.bRightParent
- ? res.pGrandParent->m_pRight.load(memory_model::memory_order_relaxed)
- : res.pGrandParent->m_pLeft.load(memory_model::memory_order_relaxed)
- ) == res.pParent
- &&
- static_cast<leaf_node *>(
- res.bRightLeaf
- ? res.pParent->m_pRight.load(memory_model::memory_order_relaxed)
- : res.pParent->m_pLeft.load(memory_model::memory_order_relaxed)
- ) == res.pLeaf;
+ return static_cast<internal_node *>(res.pGrandParent->get_child( res.bRightParent, memory_model::memory_order_relaxed )) == res.pParent
+ && static_cast<leaf_node *>( res.pParent->get_child( res.bRightLeaf, memory_model::memory_order_relaxed )) == res.pLeaf;
}
bool help_delete( update_desc * pOp )
}
}
- tree_node * protect_sibling( typename gc::Guard& guard, atomics::atomic<tree_node *>& sibling )
+ static tree_node * protect_sibling( typename gc::Guard& guard, atomics::atomic<tree_node *>& sibling )
{
- typename gc::Guard guardLeaf;
-
- tree_node * pSibling;
- tree_node * p = sibling.load( memory_model::memory_order_relaxed );
- do {
- pSibling = p;
- guard.assign( static_cast<internal_node *>(p) );
- guardLeaf.assign( node_traits::to_value_ptr( static_cast<leaf_node *>(p)));
- } while ( pSibling != ( p = sibling.load( memory_model::memory_order_acquire )) );
-
+ tree_node * pSibling = guard.protect( sibling, [](tree_node * p) -> internal_node* { return static_cast<internal_node *>(p); } );
if ( pSibling->is_leaf() )
- guard.copy( guardLeaf );
-
+ guard.assign( node_traits::to_value_ptr( static_cast<leaf_node *>( pSibling )));
return pSibling;
}
assert( res.pLeaf->is_leaf() );
// check search result
- if ( (res.bRightLeaf
- ? res.pParent->m_pRight.load( memory_model::memory_order_acquire )
- : res.pParent->m_pLeft.load( memory_model::memory_order_acquire )) == res.pLeaf ) {
+ if ( res.pParent->get_child( res.bRightLeaf, memory_model::memory_order_acquire ) == res.pLeaf ) {
leaf_node * pNewLeaf = node_traits::to_node_ptr( val );
int nCmp = node_compare()(val, *res.pLeaf);
}
else {
assert( !res.pLeaf->is_internal() );
- pNewInternal->infinite_key( 0 );
+ pNewInternal->infinite_key( 0 );
key_extractor()(pNewInternal->m_Key, val);
pNewInternal->m_pLeft.store( static_cast<tree_node *>(res.pLeaf), memory_model::memory_order_relaxed );
pNewInternal->m_pRight.store( static_cast<tree_node *>(pNewLeaf), memory_model::memory_order_release );
}
template <typename Q>
- bool extract_( typename gc::Guard& guard, Q const& key )
+ bool extract_( typename guarded_ptr::native_guard& guard, Q const& key )
{
return erase_( key, node_compare(),
[]( Q const&, leaf_node const& ) -> bool { return true; },
- [&guard]( value_type& found ) { guard.assign( &found ); } );
+ [&guard]( value_type& found ) { guard.set( &found ); } );
}
template <typename Q, typename Less>
- bool extract_with_( typename gc::Guard& guard, Q const& key, Less pred )
+ bool extract_with_( typename guarded_ptr::native_guard& guard, Q const& key, Less /*pred*/ )
{
typedef ellen_bintree::details::compare<
key_type,
return erase_( key, compare_functor(),
[]( Q const&, leaf_node const& ) -> bool { return true; },
- [&guard]( value_type& found ) { guard.assign( &found ); } );
+ [&guard]( value_type& found ) { guard.set( &found ); } );
}
- bool extract_max_( typename gc::Guard& guard )
+ bool extract_max_( typename guarded_ptr::native_guard& gp )
{
update_desc * pOp = nullptr;
search_result res;
update_ptr updGP( res.updGrandParent.ptr() );
if ( res.pGrandParent->m_pUpdate.compare_exchange_strong( updGP, update_ptr( pOp, update_desc::DFlag ),
- memory_model::memory_order_acquire, atomics::memory_order_relaxed ) )
+ memory_model::memory_order_acquire, atomics::memory_order_relaxed ) )
{
if ( help_delete( pOp ) )
break;
--m_ItemCounter;
m_Stat.onExtractMaxSuccess();
- guard.assign( node_traits::to_value_ptr( res.pLeaf ) );
+ gp.set( node_traits::to_value_ptr( res.pLeaf ));
return true;
}
- bool extract_min_( typename gc::Guard& guard )
+ bool extract_min_( typename guarded_ptr::native_guard& gp )
{
update_desc * pOp = nullptr;
search_result res;
--m_ItemCounter;
m_Stat.onExtractMinSuccess();
- guard.assign( node_traits::to_value_ptr( res.pLeaf ));
+ gp.set( node_traits::to_value_ptr( res.pLeaf ));
return true;
}
}
template <typename Q, typename Less, typename Func>
- bool find_with_( Q& val, Less pred, Func f ) const
+ bool find_with_( Q& val, Less /*pred*/, Func f ) const
{
typedef ellen_bintree::details::compare<
key_type,
}
template <typename Q>
- bool get_( typename gc::Guard& guard, Q const& val ) const
+ bool get_( typename guarded_ptr::native_guard& guard, Q const& val ) const
{
- return find_( val, [&guard]( value_type& found, Q const& ) { guard.assign( &found ); } );
+ return find_( val, [&guard]( value_type& found, Q const& ) { guard.set( &found ); } );
}
template <typename Q, typename Less>
- bool get_with_( typename gc::Guard& guard, Q const& val, Less pred ) const
+ bool get_with_( typename guarded_ptr::native_guard& guard, Q const& val, Less pred ) const
{
- return find_with_( val, pred, [&guard]( value_type& found, Q const& ) { guard.assign( &found ); } );
+ return find_with_( val, pred, [&guard]( value_type& found, Q const& ) { guard.set( &found ); } );
}
//@endcond
}} // namespace cds::intrusive
-#endif // #ifndef __CDS_INTRUSIVE_IMPL_ELLEN_BINTREE_H
+#endif // #ifndef CDSLIB_INTRUSIVE_IMPL_ELLEN_BINTREE_H
projects / libcds.git / blobdiff