issue #76: added cds::atomicity::cache_friendly_item_counter to avoid false sharing

[libcds.git] / cds / container / michael_set.h

diff --git a/cds/container/michael_set.h b/cds/container/michael_set.h
index cdd383f4694d1831f40945a5288fb903632a3036..fb23c442295181c517e7fa2917fc88a8ecf105ea 100644 (file)
--- a/cds/container/michael_set.h
+++ b/cds/container/michael_set.h
@@ -188,10 +188,6 @@ namespace cds { namespace container {
         // GC and OrderedList::gc must be the same
         static_assert( std::is_same<gc, typename ordered_list::gc>::value, "GC and OrderedList::gc must be the same");
 
-        // atomicity::empty_item_counter is not allowed as a item counter
-        static_assert( !std::is_same<item_counter, atomicity::empty_item_counter>::value,
-                        "cds::atomicity::empty_item_counter is not allowed as a item counter");
-
         //@cond
         typedef typename ordered_list::template select_stat_wrapper< typename ordered_list::stat > bucket_stat;
 
@@ -213,8 +209,8 @@ namespace cds { namespace container {
         //@cond
         size_t const           m_nHashBitmask;
         internal_bucket_type * m_Buckets;     ///< bucket table
-        item_counter           m_ItemCounter; ///< Item counter
         hash                   m_HashFunctor; ///< Hash functor
+        item_counter           m_ItemCounter; ///< Item counter
         stat                   m_Stat;        ///< Internal statistics
         //@endcond
 
@@ -868,8 +864,8 @@ namespace cds { namespace container {
 
         /// Checks if the set is empty
         /**
-            Emptiness is checked by item counting: if item count is zero then the set is empty.
-            Thus, the correct item counting feature is an important part of Michael's set implementation.
+            @warning If you use \p atomicity::empty_item_counter in \p traits::item_counter,
+            the function always returns \p true.
         */
         bool empty() const
         {
@@ -877,6 +873,10 @@ namespace cds { namespace container {
         }
 
         /// Returns item count in the set
+        /**
+            @warning If you use \p atomicity::empty_item_counter in \p traits::item_counter,
+            the function always returns 0.
+        */
         size_t size() const
         {
             return m_ItemCounter;