Tenure allocation sites only when semi-space is maximum size.

src/objects.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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include "allocation.h"
 #include "assert-scope.h"
 #include "builtins.h"
@@ skipping 8386 matching lines @@
 class AllocationSite: public Struct {
  public:
   static const uint32_t kMaximumArrayBytesToPretransition = 8 * 1024;
   static const double kPretenureRatio;
   static const int kPretenureMinimumCreated = 100;
 
   // Values for pretenure decision field.
   enum PretenureDecision {
     kUndecided = 0,
     kDontTenure = 1,
-    kTenure = 2,
-    kZombie = 3,
+    kMaybeTenure = 2,
+    kTenure = 3,
+    kZombie = 4,
     kLastPretenureDecisionValue = kZombie
   };
 
+  const char* PretenureDecisionName(PretenureDecision decision);
+
   DECL_ACCESSORS(transition_info, Object)
   // nested_site threads a list of sites that represent nested literals
   // walked in a particular order. So [[1, 2], 1, 2] will have one
   // nested_site, but [[1, 2], 3, [4]] will have a list of two.
   DECL_ACCESSORS(nested_site, Object)
   DECL_ACCESSORS(pretenure_data, Smi)
   DECL_ACCESSORS(pretenure_create_count, Smi)
   DECL_ACCESSORS(dependent_code, DependentCode)
   DECL_ACCESSORS(weak_next, Object)
 
   inline void Initialize();
 
   // This method is expensive, it should only be called for reporting.
   bool IsNestedSite();
 
   // transition_info bitfields, for constructed array transition info.
   class ElementsKindBits:       public BitField<ElementsKind, 0,  15> {};
   class UnusedBits:             public BitField<int,          15, 14> {};
   class DoNotInlineBit:         public BitField<bool,         29,  1> {};
 
   // Bitfields for pretenure_data
-  class MementoFoundCountBits:  public BitField<int,               0, 27> {};
-  class PretenureDecisionBits:  public BitField<PretenureDecision, 27, 2> {};
+  class MementoFoundCountBits:  public BitField<int,               0, 26> {};
+  class PretenureDecisionBits:  public BitField<PretenureDecision, 26, 3> {};
   class DeoptDependentCodeBit:  public BitField<bool,              29, 1> {};
   STATIC_ASSERT(PretenureDecisionBits::kMax >= kLastPretenureDecisionValue);
 
   // Increments the mementos found counter and returns true when the first
   // memento was found for a given allocation site.
   inline bool IncrementMementoFoundCount();
 
   inline void IncrementMementoCreateCount();
 
   PretenureFlag GetPretenureMode();
@@ skipping 42 matching lines @@
   // The pretenuring decision is made during gc, and the zombie state allows
   // us to recognize when an allocation site is just being kept alive because
   // a later traversal of new space may discover AllocationMementos that point
   // to this AllocationSite.
   bool IsZombie() {
     return pretenure_decision() == kZombie;
   }
 
   inline void MarkZombie();
 
-  inline bool DigestPretenuringFeedback();
+  inline bool MakePretenureDecision(PretenureDecision current_decision,
+                                    double ratio,
+                                    bool maximum_size_scavenge);
+
+  inline bool DigestPretenuringFeedback(bool maximum_size_scavenge);
 
   ElementsKind GetElementsKind() {
     ASSERT(!SitePointsToLiteral());
     int value = Smi::cast(transition_info())->value();
     return ElementsKindBits::decode(value);
   }
 
   void SetElementsKind(ElementsKind kind) {
     int value = Smi::cast(transition_info())->value();
     set_transition_info(Smi::FromInt(ElementsKindBits::update(value, kind)),
@@ skipping 2566 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_