X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=cds%2Furcu%2Fdetails%2Fgp.h;h=b8173c4c1c65590dc1fc45c3048ecd75490fb777;hb=HEAD;hp=ad2fb01a26fdeb066c62896e3a34a5f300611465;hpb=dcfc955eac8d172e1da77d150edc6e17b54ef5a0;p=libcds.git

diff --git a/cds/urcu/details/gp.h b/cds/urcu/details/gp.h
index ad2fb01a..b8173c4c 100644
--- a/cds/urcu/details/gp.h
+++ b/cds/urcu/details/gp.h
@@ -1,7 +1,7 @@
 /*
     This file is a part of libcds - Concurrent Data Structures library
 
-    (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2016
+    (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
 
     Source code repo: http://github.com/khizmax/libcds/
     Download: http://sourceforge.net/projects/libcds/files/
@@ -43,7 +43,7 @@ namespace cds { namespace urcu { namespace details {
     template <typename RCUtag>
     inline gp_thread_gc<RCUtag>::gp_thread_gc()
     {
-        if ( !threading::Manager::isThreadAttached() )
+        if ( !threading::Manager::isThreadAttached())
             cds::threading::Manager::attachThread();
     }
 
@@ -68,12 +68,13 @@ namespace cds { namespace urcu { namespace details {
         uint32_t tmp = pRec->m_nAccessControl.load( atomics::memory_order_relaxed );
         if ( (tmp & rcu_class::c_nNestMask) == 0 ) {
             pRec->m_nAccessControl.store( gp_singleton<RCUtag>::instance()->global_control_word(atomics::memory_order_relaxed),
-                atomics::memory_order_release );
-            atomics::atomic_thread_fence( atomics::memory_order_acquire );
-            CDS_COMPILER_RW_BARRIER;
+                atomics::memory_order_relaxed );
+
+            atomics::atomic_thread_fence( atomics::memory_order_seq_cst );
         }
         else {
-            pRec->m_nAccessControl.fetch_add( 1, atomics::memory_order_relaxed );
+            // nested lock
+            pRec->m_nAccessControl.store( tmp + 1, atomics::memory_order_relaxed );
         }
     }
 
@@ -83,8 +84,15 @@ namespace cds { namespace urcu { namespace details {
         thread_record * pRec = get_thread_record();
         assert( pRec != nullptr );
 
+        uint32_t tmp = pRec->m_nAccessControl.load( atomics::memory_order_relaxed );
+        assert( (tmp & rcu_class::c_nNestMask) > 0 );
+
+#if CDS_COMPILER == CDS_COMPILER_CLANG && CDS_COMPILER_VERSION < 30800
+        // CLang 3.6-3.7: some tests of intrusive::FeldmanHashSet based on general-purpose RCU
+        // are failed even in single-threaded mode (unit tests) without magic compiler barrier below
         CDS_COMPILER_RW_BARRIER;
-        pRec->m_nAccessControl.fetch_sub( 1, atomics::memory_order_release );
+#endif
+        pRec->m_nAccessControl.store( tmp - 1, atomics::memory_order_release );
     }
 
     template <typename RCUtag>
@@ -114,7 +122,7 @@ namespace cds { namespace urcu { namespace details {
         m_nGlobalControl.fetch_xor( general_purpose_rcu::c_nControlBit, atomics::memory_order_seq_cst );
 
         for ( thread_record * pRec = m_ThreadList.head( atomics::memory_order_acquire ); pRec; pRec = pRec->m_list.m_pNext ) {
-            while ( pRec->m_list.m_idOwner.load( atomics::memory_order_acquire ) != nullThreadId && check_grace_period( pRec ) ) {
+            while ( pRec->m_list.m_idOwner.load( atomics::memory_order_acquire ) != nullThreadId && check_grace_period( pRec )) {
                 bkoff();
                 CDS_COMPILER_RW_BARRIER;
             }