Start incremental marking on idle notification.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 522861deda05e2a163861ac527be202631387441..945587f92fb4e63b301d846c4f2e648796c08ca7 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -140,6 +140,7 @@ Heap::Heap()
       store_buffer_(this),
       marking_(this),
       incremental_marking_(this),
+      idle_work_(IDLE_INCREMENTAL_MARKING),
       number_idle_notifications_(0),
       last_idle_notification_gc_count_(0),
       last_idle_notification_gc_count_init_(false),
@@ -4515,6 +4516,36 @@ void Heap::EnsureHeapIsIterable() {
 
 
 bool Heap::IdleNotification() {
+  switch (idle_work_) {
+    case IDLE_INCREMENTAL_MARKING:
+      if (IdleIncrementalMarking()) {
+        idle_work_ = IDLE_GLOBAL_GC;
+      }
+      break;
+    case IDLE_GLOBAL_GC:
+      if (IdleGlobalGC()) {
+        idle_work_ = IDLE_INCREMENTAL_MARKING;
+        return true;
+      }
+      break;
+    default:
+      UNREACHABLE();
+  }
+  return false;
+}
+
+bool Heap::IdleIncrementalMarking() {
+  if (incremental_marking()->IsStopped()) {
+    if (!incremental_marking()->WorthActivating()) {
+      return true;
+    }
+    incremental_marking()->Start();
+  }
+  incremental_marking()->Step(IncrementalMarking::kStepFakeAllocatedBytes);
+  return incremental_marking()->IsComplete();

[Vyacheslav Egorov (Chromium), 2011/10/12 07:41:00]

when it's complete it makes sense to do a finishing GC immediately without
giving JS chance to mutate anything.

+}
+
+bool Heap::IdleGlobalGC() {
   static const int kIdlesBeforeScavenge = 4;
   static const int kIdlesBeforeMarkSweep = 7;
   static const int kIdlesBeforeMarkCompact = 8;