// c_nMaxHeight * 2 - pPred/pSucc guards
// + 1 - for erase, unlink
// + 1 - for clear
- // + 1 - for help_remove
- static size_t const c_nHazardPtrCount = c_nMaxHeight * 2 + 3; ///< Count of hazard pointer required for the skip-list
+ static size_t const c_nHazardPtrCount = c_nMaxHeight * 2 + 2; ///< Count of hazard pointer required for the skip-list
protected:
typedef typename node_type::atomic_marked_ptr atomic_node_ptr; ///< Atomic marked node pointer
void help_remove( int nLevel, node_type* pPred, marked_node_ptr pCur, marked_node_ptr pSucc )
{
- typename gc::Guard succ_guard;
- marked_node_ptr succ = succ_guard.protect( pCur->next( nLevel ), gc_protect );
-
- typename node_type::state state = node_type::clean;
- if ( succ == pSucc && ( succ.ptr() == nullptr ||
- succ.ptr()->set_state( state, node_type::hand_off, memory_model::memory_order_acquire )))
+ marked_node_ptr p( pCur.ptr() );
+ if ( pPred->next( nLevel ).compare_exchange_strong( p, marked_node_ptr( pSucc.ptr()),
+ memory_model::memory_order_acquire, atomics::memory_order_relaxed ) )
{
- marked_node_ptr p( pCur.ptr() );
- if ( pPred->next( nLevel ).compare_exchange_strong( p, marked_node_ptr( succ.ptr()),
- memory_model::memory_order_acquire, atomics::memory_order_relaxed ) )
- {
- if ( nLevel == 0 ) {
- gc::retire( node_traits::to_value_ptr( pCur.ptr() ), dispose_node );
- m_Stat.onEraseWhileFind();
- }
+ if ( nLevel == 0 ) {
+ gc::retire( node_traits::to_value_ptr( pCur.ptr() ), dispose_node );
+ m_Stat.onEraseWhileFind();
}
-
- if ( succ.ptr() )
- succ.ptr()->clear_state( memory_model::memory_order_release );
}
- else if ( succ.ptr() != nullptr )
- m_Stat.onNodeHandOffFailed();
}
template <typename Q, typename Compare >
// Insert at level 0
{
node_type* succ = pos.pSucc[0];
- typename node_type::state state = node_type::clean;
- if ( succ != nullptr && !succ->set_state( state, node_type::hand_off, memory_model::memory_order_acquire ) )
- return false;
marked_node_ptr p( succ );
pNode->next( 0 ).store( p, memory_model::memory_order_release );
- if ( !pos.pPrev[0]->next( 0 ).compare_exchange_strong( p, marked_node_ptr( pNode ), memory_model::memory_order_release, atomics::memory_order_relaxed ) ) {
- if ( succ )
- succ->clear_state( memory_model::memory_order_release );
+ if ( !pos.pPrev[0]->next( 0 ).compare_exchange_strong( p, marked_node_ptr( pNode ), memory_model::memory_order_release, atomics::memory_order_relaxed ))
return false;
- }
- if ( succ )
- succ->clear_state( memory_model::memory_order_release );
f( val );
}
for ( unsigned int nLevel = 1; nLevel < nHeight; ++nLevel ) {
marked_node_ptr p;
while ( true ) {
- typename node_type::state state = node_type::clean;
- node_type* succ = pos.pSucc[nLevel];
- if ( succ == nullptr ||
- succ->set_state( state, node_type::hand_off, memory_model::memory_order_acquire ) )
- {
- marked_node_ptr q( succ );
- if ( !pNode->next( nLevel ).compare_exchange_strong( p, q, memory_model::memory_order_release, atomics::memory_order_relaxed )) {
- // pNode has been marked as removed while we are inserting it
- // Stop inserting
- if ( succ )
- succ->clear_state( memory_model::memory_order_release );
- assert( p.bits() );
- m_Stat.onLogicDeleteWhileInsert();
- return true;
- }
+ marked_node_ptr q( pos.pSucc[nLevel] );
- p = q;
- bool const result = pos.pPrev[nLevel]->next( nLevel ).compare_exchange_strong( q, marked_node_ptr( pNode ),
- memory_model::memory_order_release, atomics::memory_order_relaxed );
- if ( succ )
- succ->clear_state( memory_model::memory_order_release );
- if ( result )
- break;
+ if ( !pNode->next( nLevel ).compare_exchange_strong( p, q, memory_model::memory_order_release, atomics::memory_order_relaxed )) {
+ // pNode has been marked as removed while we are inserting it
+ // Stop inserting
+ assert( p.bits() );
+ m_Stat.onLogicDeleteWhileInsert();
+ return true;
}
+ p = q;
+ bool const result = pos.pPrev[nLevel]->next( nLevel ).compare_exchange_strong( q, marked_node_ptr( pNode ),
+ memory_model::memory_order_release, atomics::memory_order_relaxed );
+ if ( result )
+ break;
+
// Renew insert position
m_Stat.onRenewInsertPosition();
if ( !find_position( val, pos, key_comparator(), false ) ) {
{
assert( pDel != nullptr );
- // set "removed" node state
- {
- back_off bkoff;
- typename node_type::state state = node_type::clean;
- while ( !( pDel->set_state( state, node_type::removed, memory_model::memory_order_release )
- || state == node_type::removed ))
- {
- bkoff();
- }
- }
-
marked_node_ptr pSucc;
// logical deletion (marking)