Merge branch 'dev'

[libcds.git] / cds / intrusive / optimistic_queue.h

diff --git a/cds/intrusive/optimistic_queue.h b/cds/intrusive/optimistic_queue.h
index f316baa2790754a2c2f34ede0824169eefa39b33..0f98f75f7988faceb9136e05257dca042703bfc7 100644 (file)
--- a/cds/intrusive/optimistic_queue.h
+++ b/cds/intrusive/optimistic_queue.h
@@ -1,11 +1,11 @@
 //$$CDS-header$$
 
-#ifndef __CDS_INTRUSIVE_OPTIMISTIC_QUEUE_H
-#define __CDS_INTRUSIVE_OPTIMISTIC_QUEUE_H
+#ifndef CDSLIB_INTRUSIVE_OPTIMISTIC_QUEUE_H
+#define CDSLIB_INTRUSIVE_OPTIMISTIC_QUEUE_H
 
 #include <type_traits>
 #include <cds/intrusive/details/base.h>
-#include <cds/cxx11_atomic.h>
+#include <cds/algo/atomic.h>
 #include <cds/gc/default_gc.h>
 
 namespace cds { namespace intrusive {
@@ -116,6 +116,7 @@ namespace cds { namespace intrusive {
             {
                 assert( pNode->m_pNext.load( atomics::memory_order_relaxed ) == nullptr );
                 assert( pNode->m_pPrev.load( atomics::memory_order_relaxed ) == nullptr );
+                CDS_UNUSED( pNode );
             }
         };
 
@@ -158,13 +159,14 @@ namespace cds { namespace intrusive {
         {
             typedef Counter     counter_type;   ///< Counter type
 
-            counter_type m_EnqueueCount;  ///< Enqueue call count
-            counter_type m_DequeueCount;  ///< Dequeue call count
-            counter_type m_EnqueueRace;  ///< Count of enqueue race conditions encountered
-            counter_type m_DequeueRace;  ///< Count of dequeue race conditions encountered
-            counter_type m_AdvanceTailError;  ///< Count of "advance tail failed" events
-            counter_type m_BadTail;  ///< Count of events "Tail is not pointed to the last item in the queue"
-            counter_type    m_FixListCount;   ///< Count of fix list event
+            counter_type m_EnqueueCount;    ///< Enqueue call count
+            counter_type m_DequeueCount;    ///< Dequeue call count
+            counter_type m_EnqueueRace;     ///< Count of enqueue race conditions encountered
+            counter_type m_DequeueRace;     ///< Count of dequeue race conditions encountered
+            counter_type m_AdvanceTailError; ///< Count of "advance tail failed" events
+            counter_type m_BadTail;         ///< Count of events "Tail is not pointed to the last item in the queue"
+            counter_type m_FixListCount;    ///< Count of fix list event
+            counter_type m_EmptyDequeue;    ///< Count of dequeue from empty queue
 
             /// Register enqueue call
             void onEnqueue() { ++m_EnqueueCount; }
@@ -180,6 +182,8 @@ namespace cds { namespace intrusive {
             void onBadTail() { ++m_BadTail; }
             /// Register fix list event
             void onFixList()    { ++m_FixListCount; }
+            /// Register dequeuing from empty queue
+            void onEmptyDequeue() { ++m_EmptyDequeue; }
 
             //@cond
             void reset()
@@ -191,6 +195,7 @@ namespace cds { namespace intrusive {
                 m_AdvanceTailError.reset();
                 m_BadTail.reset();
                 m_FixListCount.reset();
+                m_EmptyDequeue.reset();
             }
 
             stat& operator +=( stat const& s )
@@ -202,6 +207,8 @@ namespace cds { namespace intrusive {
                 m_AdvanceTailError += s.m_AdvanceTailError.get();
                 m_BadTail += s.m_BadTail.get();
                 m_FixListCount += s.m_FixListCount.get();
+                m_EmptyDequeue += s.m_EmptyDequeue.get();
+
                 return *this;
             }
             //@endcond
@@ -211,13 +218,14 @@ namespace cds { namespace intrusive {
         struct empty_stat
         {
             //@cond
-            void onEnqueue() {}
-            void onDequeue() {}
-            void onEnqueueRace() {}
-            void onDequeueRace() {}
-            void onAdvanceTailFailed() {}
-            void onBadTail() {}
-            void onFixList() {}
+            void onEnqueue()            const {}
+            void onDequeue()            const {}
+            void onEnqueueRace()        const {}
+            void onDequeueRace()        const {}
+            void onAdvanceTailFailed()  const {}
+            void onBadTail()            const {}
+            void onFixList()            const {}
+            void onEmptyDequeue()       const {}
 
             void reset() {}
             empty_stat& operator +=( empty_stat const& )
@@ -465,13 +473,14 @@ namespace cds { namespace intrusive {
                             fix_list( pTail, pHead );
                             continue;
                         }
-                        if ( m_pHead.compare_exchange_weak( pHead, pFirstNodePrev, memory_model::memory_order_release, atomics::memory_order_relaxed )) {
+                        if ( m_pHead.compare_exchange_weak( pHead, pFirstNodePrev, memory_model::memory_order_acquire, atomics::memory_order_relaxed )) {
                             // dequeue success
                             break;
                         }
                     }
                     else {
                         // the queue is empty
+                        m_Stat.onEmptyDequeue();
                         return false;
                     }
                 }
@@ -671,4 +680,4 @@ namespace cds { namespace intrusive {
 
 }}  // namespace cds::intrusive
 
-#endif // #ifndef __CDS_INTRUSIVE_OPTIMISTIC_QUEUE_H
+#endif // #ifndef CDSLIB_INTRUSIVE_OPTIMISTIC_QUEUE_H