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

src/incremental-marking.cc

Index: src/incremental-marking.cc
diff --git a/src/incremental-marking.cc b/src/incremental-marking.cc
index 7aadd279dc6d4f739f2642515acbdb2e9673eb14..bacbb93ad2e8cb6a335c577e8ccf69ade8c82d63 100644
--- a/src/incremental-marking.cc
+++ b/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);
   }