Check if there is still time before finalizing an incremental collection.

src/heap/incremental-marking.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_INCREMENTAL_MARKING_H_
 #define V8_HEAP_INCREMENTAL_MARKING_H_
 
 
 #include "src/execution.h"
 #include "src/heap/mark-compact.h"
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
 
 
 class IncrementalMarking {
  public:
   enum State { STOPPED, SWEEPING, MARKING, COMPLETE };
 
   enum CompletionAction { GC_VIA_STACK_GUARD, NO_GC_VIA_STACK_GUARD };
 
+  enum ForceMarkingAction { FORCE_MARKING, DO_NOT_FORCE_MARKING };
+
+  enum ForceCompletionAction { FORCE_COMPLETION, DO_NOT_FORCE_COMPLETION };
+
   explicit IncrementalMarking(Heap* heap);
 
   static void Initialize();
 
   void TearDown();
 
   State state() {
     DCHECK(state_ == STOPPED || FLAG_incremental_marking);
     return state_;
   }
@@ skipping 43 matching lines @@
   static const intptr_t kInitialMarkingSpeed = 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 kMarkingSpeedAccellerationInterval = 1024;
   // This is how much we increase the marking/allocating factor by.
   static const intptr_t kMarkingSpeedAccelleration = 2;
   static const intptr_t kMaxMarkingSpeed = 1000;
 
+  // This is the upper bound for how many times we allow finalization of
+  // incremental marking to be postponed.
+  static const size_t kMaxIdleMarkingDelayCounter = 3;
+
   void OldSpaceStep(intptr_t allocated);
 
-  void Step(intptr_t allocated, CompletionAction action,
-            bool force_marking = false);
+  intptr_t Step(intptr_t allocated, CompletionAction action,
+                ForceMarkingAction marking = DO_NOT_FORCE_MARKING,
+                ForceCompletionAction completion = FORCE_COMPLETION);
 
   inline void RestartIfNotMarking() {
     if (state_ == COMPLETE) {
       state_ = MARKING;
       if (FLAG_trace_incremental_marking) {
         PrintF("[IncrementalMarking] Restarting (new grey objects)\n");
       }
     }
   }
 
@@ skipping 58 matching lines @@
   void EnterNoMarkingScope() { no_marking_scope_depth_++; }
 
   void LeaveNoMarkingScope() { no_marking_scope_depth_--; }
 
   void UncommitMarkingDeque();
 
   void NotifyIncompleteScanOfObject(int unscanned_bytes) {
     unscanned_bytes_of_large_object_ = unscanned_bytes;
   }
 
+  void ClearIdleMarkingDelayCounter();
+
+  bool IsIdleMarkingDelayCounterLimitReached();
+
  private:
   int64_t SpaceLeftInOldSpace();
 
   void SpeedUp();
 
   void ResetStepCounters();
 
   void StartMarking(CompactionFlag flag);
 
   void ActivateIncrementalWriteBarrier(PagedSpace* space);
@@ skipping 10 matching lines @@
   static void SetNewSpacePageFlags(NewSpacePage* chunk, bool is_marking);
 
   void EnsureMarkingDequeIsCommitted();
 
   INLINE(void ProcessMarkingDeque());
 
   INLINE(intptr_t ProcessMarkingDeque(intptr_t bytes_to_process));
 
   INLINE(void VisitObject(Map* map, HeapObject* obj, int size));
 
+  void IncrementIdleMarkingDelayCounter();
+
   Heap* heap_;
 
   State state_;
   bool is_compacting_;
 
   base::VirtualMemory* marking_deque_memory_;
   bool marking_deque_memory_committed_;
   MarkingDeque marking_deque_;
 
   int steps_count_;
   int64_t old_generation_space_available_at_start_of_incremental_;
   int64_t old_generation_space_used_at_start_of_incremental_;
   int64_t bytes_rescanned_;
   bool should_hurry_;
   int marking_speed_;
   intptr_t bytes_scanned_;
   intptr_t allocated_;
   intptr_t write_barriers_invoked_since_last_step_;
+  size_t idle_marking_delay_counter_;
 
   int no_marking_scope_depth_;
 
   int unscanned_bytes_of_large_object_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(IncrementalMarking);
 };
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_INCREMENTAL_MARKING_H_