Start incremental marking on idle notification.

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index f488b8cda276316df11e6df8b3e645a533c8b111..3ed717c4aa435f894b9ac4bbdf5f3735a42e0c79 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -1427,6 +1427,10 @@ class Heap {
   // The roots that have an index less than this are always in old space.
   static const int kOldSpaceRoots = 0x20;
 
+  bool idle_notification_will_schedule_next_gc() {
+    return idle_notification_will_schedule_next_gc_;
+  }
+
  private:
   Heap();
 
@@ -1752,6 +1756,23 @@ class Heap {
 
   void SelectScavengingVisitorsTable();
 
+  bool WorthStartingGCWhenIdle() {
+    if (contexts_disposed_ > 0) {
+      return true;
+    }
+    if (number_idle_notifications_ < kMaxIdleCount) {
+      return incremental_marking()->WorthActivating();
+    }
+    if (gc_count_ - last_idle_notification_gc_count_ > kGCsBetweenCleanup) {
+      return incremental_marking()->WorthActivating() &&
+             NextGCIsLikelyToBeFull();
+    }
+    return false;
+  }
+
+  // Returns true if no more GC work is left.
+  bool IdleGlobalGC();
+
   static const int kInitialSymbolTableSize = 2048;
   static const int kInitialEvalCacheSize = 64;
 
@@ -1777,9 +1798,18 @@ class Heap {
 
   IncrementalMarking incremental_marking_;
 
+  static const int kIdlesBeforeScavenge = 4;
+  static const int kIdlesBeforeMarkSweep = 7;
+  static const int kIdlesBeforeMarkCompact = 8;
+  static const int kMaxIdleCount = kIdlesBeforeMarkCompact + 1;

[Erik Corry, 2011/11/10 15:06:55]

The name kMaxIdleCount no longer makes much sense.  Can't we get any more idle
notifications than this, and why not?

[ulan, 2011/11/11 13:27:26]

Now I don't use this constant in the new IdleNotification.

+  static const unsigned int kGCsBetweenCleanup = 4;

[Erik Corry, 2011/11/10 15:06:55]

I suggest kScavengesBeforeFullGC for this one.

[ulan, 2011/11/11 13:27:26]

Ditto.

+
   int number_idle_notifications_;
   unsigned int last_idle_notification_gc_count_;
   bool last_idle_notification_gc_count_init_;
+  bool idle_notification_will_schedule_next_gc_;
+  double last_idle_notification_timestamp_;
+
 
   // Shared state read by the scavenge collector and set by ScavengeObject.
   PromotionQueue promotion_queue_;