sysbarrier

Author: Thomas Schatzl

src/hotspot/share/gc/g1/c2/g1BarrierSetC2.cpp

@@ -468,9 +468,9 @@ void G1BarrierSetC2::post_barrier(GraphKit* kit,
         Node* card_val = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
 
         __ if_then(card_val, BoolTest::ne, young_card, unlikely); {
-          kit->sync_kit(ideal);
-          kit->insert_mem_bar(Op_MemBarVolatile, oop_store);
-          __ sync_kit(kit);
+          //kit->sync_kit(ideal);
+          //kit->insert_mem_bar(Op_MemBarVolatile, oop_store);
+          //__ sync_kit(kit);
 
           Node* card_val_reload = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
           __ if_then(card_val_reload, BoolTest::ne, dirty_card); {

src/hotspot/share/gc/g1/g1DirtyCardQueue.cpp

@@ -52,6 +52,7 @@
 #include "utilities/pair.hpp"
 #include "utilities/quickSort.hpp"
 #include "utilities/ticks.hpp"
+#include "utilities/systemMemoryBarrier.hpp"
 
 G1DirtyCardQueue::G1DirtyCardQueue(G1DirtyCardQueueSet* qset) :
   PtrQueue(qset),
@@ -447,7 +448,7 @@ class G1RefineBufferedCards : public StackObj {
     // setting the regions' tops in humongous allocation path).
     // It's okay that reading region's top and reading region's type were racy
     // wrto each other. We need both set, in any order, to proceed.
-    OrderAccess::fence();
+    SystemMemoryBarrier::emit();
     sort_cards(first_clean_index);
     return refine_cleaned_cards(first_clean_index);
   }

src/hotspot/share/runtime/globals.hpp

@@ -1288,7 +1288,7 @@ const int ObjectAlignmentInBytes = 8;
           "supports sub-millisecond resolution with fractional values.")    \
           range(0, max_jlongDouble LP64_ONLY(/MICROUNITS))                  \
                                                                             \
-  product(bool, UseSystemMemoryBarrier, false,                              \
+  product(bool, UseSystemMemoryBarrier, true,                              \
           "Try to enable system memory barrier if supported by OS")         \
                                                                             \
   product(intx, NmethodSweepActivity, 4,                                    \