Parallelize marking phase of mark-sweep/compact collection cycle.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 23bfbd807d8d1430e4e38c3dc9044c41652dfe3f..51408a9dc0e7f72d9993f5e2695ef823d5a38b4f 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -51,6 +51,7 @@
 namespace v8 {
 namespace internal {
 
+Atomic32 RootsPartitioner::partitions_state_[kNumberOfRootsPartitions];
 
 String* Heap::hidden_symbol_;
 Object* Heap::roots_[Heap::kRootListLength];
@@ -4039,6 +4040,69 @@ void Heap::IterateStrongRoots(ObjectVisitor* v, VisitMode mode) {
 }
 
 
+void Heap::ClaimAndIterateStrongRootsGroup(ObjectVisitor* v,
+                                           VisitMode mode,
+                                           RootsPartition partition) {
+  if (!RootsPartitioner::Claim(partition)) return;
+
+  switch (partition) {
+    case kStrongRootsList:
+      v->VisitPointers(&roots_[0], &roots_[kStrongRootListLength]);
+      v->VisitPointer(BitCast<Object**>(&hidden_symbol_));
+      break;
+
+    case kBootstrapperRoots:
+      Bootstrapper::Iterate(v);
+      break;
+
+    case kTopRoots:
+      Top::Iterate(v);
+      break;
+
+    case kRelocatableRoots:
+      Relocatable::Iterate(v);
+      break;
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+    case kDebugRoots:
+      Debug::Iterate(v);
+      break;
+#endif
+
+    case kCompilationCacheRoots:
+      CompilationCache::Iterate(v);
+      break;
+
+    case kHandleScopeRoots:
+      HandleScopeImplementer::Iterate(v);
+      break;
+
+    case kBuiltinsRoots:
+      if (mode != VISIT_ALL_IN_SCAVENGE) Builtins::IterateBuiltins(v);
+      break;
+
+    case kGlobalHandlesRoots:
+      if (mode == VISIT_ONLY_STRONG) {
+        GlobalHandles::IterateStrongRoots(v);
+      } else {
+        GlobalHandles::IterateAllRoots(v);
+      }
+      break;
+
+    case kThreadManagerRoots:
+      ThreadManager::Iterate(v);
+      break;
+
+    case kSerializerDeserializerRoots:
+      SerializerDeserializer::Iterate(v);
+      break;
+
+    default:
+      UNREACHABLE();
+  }
+}
+
+
 // Flag is set when the heap has been configured.  The heap can be repeatedly
 // configured through the API until it is setup.
 static bool heap_configured = false;
@@ -4773,14 +4837,15 @@ GCTracer::GCTracer()
       gc_count_(0),
       full_gc_count_(0),
       is_compacting_(false),
+#ifdef DEBUG
       marked_count_(0),
+#endif
       allocated_since_last_gc_(0),
       spent_in_mutator_(0),
       promoted_objects_size_(0) {
   // These two fields reflect the state of the previous full collection.
   // Set them before they are changed by the collector.
   previous_has_compacted_ = MarkCompactCollector::HasCompacted();
-  previous_marked_count_ = MarkCompactCollector::previous_marked_count();
   if (!FLAG_trace_gc && !FLAG_print_cumulative_gc_stat) return;
   start_time_ = OS::TimeCurrentMillis();
   start_size_ = Heap::SizeOfObjects();