Perform incremental marking step after free-list allocation and clean-up incremental marking start …

src/incremental-marking.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 472 matching lines @@
 
 
 bool IncrementalMarking::WorthActivating() {
 #ifndef DEBUG
   static const intptr_t kActivationThreshold = 8 * MB;
 #else
   // TODO(gc) consider setting this to some low level so that some
   // debug tests run with incremental marking and some without.
   static const intptr_t kActivationThreshold = 0;
 #endif
-
+  // Only start incremental marking in a safe state: 1) when expose GC is
+  // deactivated, 2) when incremental marking is turned on, 3) when we are
+  // currently not in a GC, and 4) when we are currently not serializing
+  // or deserializing the heap.
   return !FLAG_expose_gc &&
       FLAG_incremental_marking &&
+      FLAG_incremental_marking_steps &&
+      heap_->gc_state() == Heap::NOT_IN_GC &&
       !Serializer::enabled() &&
+      heap_->isolate()->IsInitialized() &&
       heap_->PromotedSpaceSizeOfObjects() > kActivationThreshold;
 }
 
 
 void IncrementalMarking::ActivateGeneratedStub(Code* stub) {
   ASSERT(RecordWriteStub::GetMode(stub) ==
          RecordWriteStub::STORE_BUFFER_ONLY);
 
   if (!IsMarking()) {
     // Initially stub is generated in STORE_BUFFER_ONLY mode thus
@@ skipping 47 matching lines @@
   if (state_ == STOPPED && marking_deque_memory_committed_) {
     bool success = marking_deque_memory_->Uncommit(
         reinterpret_cast<Address>(marking_deque_memory_->address()),
         marking_deque_memory_->size());
     CHECK(success);
     marking_deque_memory_committed_ = false;
   }
 }
 
 
-void IncrementalMarking::Start() {
+void IncrementalMarking::Start(CompactionFlag flag) {
   if (FLAG_trace_incremental_marking) {
     PrintF("[IncrementalMarking] Start\n");
   }
   ASSERT(FLAG_incremental_marking);
   ASSERT(FLAG_incremental_marking_steps);
   ASSERT(state_ == STOPPED);
   ASSERT(heap_->gc_state() == Heap::NOT_IN_GC);
   ASSERT(!Serializer::enabled());
   ASSERT(heap_->isolate()->IsInitialized());
 
   ResetStepCounters();
 
   if (heap_->IsSweepingComplete()) {
-    StartMarking(ALLOW_COMPACTION);
+    StartMarking(flag);
   } else {
     if (FLAG_trace_incremental_marking) {
       PrintF("[IncrementalMarking] Start sweeping.\n");
     }
     state_ = SWEEPING;
   }
 
   heap_->new_space()->LowerInlineAllocationLimit(kAllocatedThreshold);
 }
 
@@ skipping 270 matching lines @@
     PrintF("[IncrementalMarking] Complete (normal).\n");
   }
   if (action == GC_VIA_STACK_GUARD) {
     heap_->isolate()->stack_guard()->RequestGC();
   }
 }
 
 
 void IncrementalMarking::OldSpaceStep(intptr_t allocated) {
   if (IsStopped() && WorthActivating() && heap_->NextGCIsLikelyToBeFull()) {
-    // Only start incremental marking in a save state: 1) when we are not in
-    // a GC, 2) when we turned-on incremental marking, 3) when we are
-    // currently not serializing or deserializing the heap.
-    if (heap_->gc_state() != Heap::NOT_IN_GC ||
-        !FLAG_incremental_marking ||
-        !FLAG_incremental_marking_steps ||
-        Serializer::enabled() ||
-        !heap_->isolate()->IsInitialized()) {
-      return;
-    }
-    Start();
+    // TODO(hpayer): Let's play safe for now, but compaction should be
+    // in principle possible.
+    Start(PREVENT_COMPACTION);
   } else {
     Step(allocated * kFastMarking / kInitialMarkingSpeed, GC_VIA_STACK_GUARD);
   }
 }
 
 
 void IncrementalMarking::Step(intptr_t allocated_bytes,
                               CompletionAction action) {
   if (heap_->gc_state() != Heap::NOT_IN_GC ||
       !FLAG_incremental_marking ||
@@ skipping 135 matching lines @@
   bytes_scanned_ = 0;
   write_barriers_invoked_since_last_step_ = 0;
 }
 
 
 int64_t IncrementalMarking::SpaceLeftInOldSpace() {
   return heap_->MaxOldGenerationSize() - heap_->PromotedSpaceSizeOfObjects();
 }
 
 } }  // namespace v8::internal