Make progress in incremental marking if scavenge is delaying mark-sweep.

src/incremental-marking.h

 // Copyright 2011 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 28 matching lines @@
 
 class IncrementalMarking {
  public:
   enum State {
     STOPPED,
     SWEEPING,
     MARKING,
     COMPLETE
   };
 
+  enum Finalizer {

[Michael Starzinger, 2012/04/02 09:01:46]

The name "finalizer" feels wrong. Can we change this to something like ...
enum CompletionAction {
  NO_COMPLETION_ACTION,
  GC_VIA_STACK_GUARD
};

[ulan, 2012/04/02 09:42:24]

Done.

+    GC_VIA_STACK_GUARD,
+    NO_GC_VIA_STACK_GUARD
+  };
+
   explicit IncrementalMarking(Heap* heap);
 
   void TearDown();
 
   State state() {
     ASSERT(state_ == STOPPED || FLAG_incremental_marking);
     return state_;
   }
 
   bool should_hurry() { return should_hurry_; }
@@ skipping 16 matching lines @@
   void PrepareForScavenge();
 
   void UpdateMarkingDequeAfterScavenge();
 
   void Hurry();
 
   void Finalize();
 
   void Abort();
 
-  void MarkingComplete();
+  void MarkingComplete(Finalizer finalizer);
 
   // It's hard to know how much work the incremental marker should do to make
   // progress in the face of the mutator creating new work for it.  We start
   // of at a moderate rate of work and gradually increase the speed of the
   // incremental marker until it completes.
   // Do some marking every time this much memory has been allocated.
   static const intptr_t kAllocatedThreshold = 65536;
   // Start off by marking this many times more memory than has been allocated.
   static const intptr_t kInitialAllocationMarkingFactor = 1;
   // But if we are promoting a lot of data we need to mark faster to keep up
   // with the data that is entering the old space through promotion.
   static const intptr_t kFastMarking = 3;
   // After this many steps we increase the marking/allocating factor.
   static const intptr_t kAllocationMarkingFactorSpeedupInterval = 1024;
   // This is how much we increase the marking/allocating factor by.
   static const intptr_t kAllocationMarkingFactorSpeedup = 2;
   static const intptr_t kMaxAllocationMarkingFactor = 1000;
 
   void OldSpaceStep(intptr_t allocated) {
     Step(allocated * kFastMarking / kInitialAllocationMarkingFactor);
   }
 
-  void Step(intptr_t allocated);
+  void Step(intptr_t allocated, Finalizer finalizer = GC_VIA_STACK_GUARD);

[Michael Starzinger, 2012/04/02 09:01:46]

There are only three other call-sites, could we get along without a default
argument?

[ulan, 2012/04/02 09:42:24]

Done.

 
   inline void RestartIfNotMarking() {
     if (state_ == COMPLETE) {
       state_ = MARKING;
       if (FLAG_trace_incremental_marking) {
         PrintF("[IncrementalMarking] Restarting (new grey objects)\n");
       }
     }
   }
 
@@ skipping 150 matching lines @@
   intptr_t allocated_;
 
   int no_marking_scope_depth_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(IncrementalMarking);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_INCREMENTAL_MARKING_H_