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

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

BUG=

Review URL: https://codereview.chromium.org/14634007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14564 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/incremental-marking.cc

@@ -490,10 +490,16 @@ bool IncrementalMarking::WorthActivating() {
   // 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;
 }
 
@@ -561,7 +567,7 @@ void IncrementalMarking::UncommitMarkingDeque() {
 }
 
 
-void IncrementalMarking::Start() {
+void IncrementalMarking::Start(CompactionFlag flag) {
   if (FLAG_trace_incremental_marking) {
     PrintF("[IncrementalMarking] Start\n");
   }
@@ -575,7 +581,7 @@ void IncrementalMarking::Start() {
   ResetStepCounters();
 
   if (heap_->IsSweepingComplete()) {
-    StartMarking(ALLOW_COMPACTION);
+    StartMarking(flag);
   } else {
     if (FLAG_trace_incremental_marking) {
       PrintF("[IncrementalMarking] Start sweeping.\n");
@@ -866,17 +872,9 @@ void IncrementalMarking::MarkingComplete(CompletionAction action) {
 
 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);
   }

src/incremental-marking.h

@@ -75,7 +75,9 @@ class IncrementalMarking {
 
   bool WorthActivating();
 
-  void Start();
+  enum CompactionFlag { ALLOW_COMPACTION, PREVENT_COMPACTION };
+
+  void Start(CompactionFlag flag = ALLOW_COMPACTION);
 
   void Stop();
 
@@ -223,8 +225,6 @@ class IncrementalMarking {
 
   void ResetStepCounters();
 
-  enum CompactionFlag { ALLOW_COMPACTION, PREVENT_COMPACTION };
-
   void StartMarking(CompactionFlag flag);
 
   void ActivateIncrementalWriteBarrier(PagedSpace* space);

src/spaces.cc

@@ -2304,14 +2304,6 @@ HeapObject* FreeList::Allocate(int size_in_bytes) {
   // Don't free list allocate if there is linear space available.
   ASSERT(owner_->limit() - owner_->top() < size_in_bytes);
 
-  int new_node_size = 0;
-  FreeListNode* new_node = FindNodeFor(size_in_bytes, &new_node_size);
-  if (new_node == NULL) return NULL;
-
-
-  int bytes_left = new_node_size - size_in_bytes;
-  ASSERT(bytes_left >= 0);
-
   int old_linear_size = static_cast<int>(owner_->limit() - owner_->top());
   // Mark the old linear allocation area with a free space map so it can be
   // skipped when scanning the heap.  This also puts it back in the free list
@@ -2321,6 +2313,16 @@ HeapObject* FreeList::Allocate(int size_in_bytes) {
   owner_->heap()->incremental_marking()->OldSpaceStep(
       size_in_bytes - old_linear_size);
 
+  int new_node_size = 0;
+  FreeListNode* new_node = FindNodeFor(size_in_bytes, &new_node_size);
+  if (new_node == NULL) {
+    owner_->SetTop(NULL, NULL);
+    return NULL;
+  }
+
+  int bytes_left = new_node_size - size_in_bytes;
+  ASSERT(bytes_left >= 0);
+
 #ifdef DEBUG
   for (int i = 0; i < size_in_bytes / kPointerSize; i++) {
     reinterpret_cast<Object**>(new_node->address())[i] =