Remove high promotion mode.

src/heap.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_H_
 #define V8_HEAP_H_
 
 #include <cmath>
 
 #include "allocation.h"
@@ skipping 1017 matching lines @@
   // Support for the API.
   //
 
   void CreateApiObjects();
 
   // Adjusts the amount of registered external memory.
   // Returns the adjusted value.
   inline int64_t AdjustAmountOfExternalAllocatedMemory(
       int64_t change_in_bytes);
 
-  // This is only needed for testing high promotion mode.
-  void SetNewSpaceHighPromotionModeActive(bool mode) {
-    new_space_high_promotion_mode_active_ = mode;
-  }
-
   // Returns the allocation mode (pre-tenuring) based on observed promotion
   // rates of previous collections.
   inline PretenureFlag GetPretenureMode() {
-    return FLAG_pretenuring && new_space_high_promotion_mode_active_
-        ? TENURED : NOT_TENURED;
-  }
-
-  inline Address* NewSpaceHighPromotionModeActiveAddress() {
-    return reinterpret_cast<Address*>(&new_space_high_promotion_mode_active_);
+    return FLAG_pretenuring ? TENURED : NOT_TENURED;
   }
 
   inline intptr_t PromotedTotalSize() {
     int64_t total = PromotedSpaceSizeOfObjects() + PromotedExternalMemorySize();
     if (total > kMaxInt) return static_cast<intptr_t>(kMaxInt);
     if (total < 0) return 0;
     return static_cast<intptr_t>(total);
   }
 
   inline intptr_t OldGenerationSpaceAvailable() {
@@ skipping 513 matching lines @@
   ROOT_LIST(ROOT_ACCESSOR)
 #undef ROOT_ACCESSOR
 
 #ifdef DEBUG
   // If the --gc-interval flag is set to a positive value, this
   // variable holds the value indicating the number of allocations
   // remain until the next failure and garbage collection.
   int allocation_timeout_;
 #endif  // DEBUG
 
-  // Indicates that the new space should be kept small due to high promotion
-  // rates caused by the mutator allocating a lot of long-lived objects.
-  // TODO(hpayer): change to bool if no longer accessed from generated code
-  intptr_t new_space_high_promotion_mode_active_;
-
   // Limit that triggers a global GC on the next (normally caused) GC.  This
   // is checked when we have already decided to do a GC to help determine
   // which collector to invoke, before expanding a paged space in the old
   // generation and on every allocation in large object space.
   intptr_t old_generation_allocation_limit_;
 
   // Used to adjust the limits that control the timing of the next GC.
   intptr_t size_of_old_gen_at_last_old_space_gc_;
 
   // Limit on the amount of externally allocated memory allowed
@@ skipping 420 matching lines @@
   // Sets used allocation sites entries to undefined.
   void FlushAllocationSitesScratchpad();
 
   // Initializes the allocation sites scratchpad with undefined values.
   void InitializeAllocationSitesScratchpad();
 
   // Adds an allocation site to the scratchpad if there is space left.
   void AddAllocationSiteToScratchpad(AllocationSite* site,
                                      ScratchpadSlotMode mode);
 
-  void UpdateSurvivalRateTrend(int start_new_space_size);
-
-  enum SurvivalRateTrend { INCREASING, STABLE, DECREASING, FLUCTUATING };
+  void UpdateSurvivalStatistics(int start_new_space_size);
 
   static const int kYoungSurvivalRateHighThreshold = 90;
-  static const int kYoungSurvivalRateLowThreshold = 10;
   static const int kYoungSurvivalRateAllowedDeviation = 15;
 
   static const int kOldSurvivalRateLowThreshold = 10;
 
   int high_survival_rate_period_length_;
-  int low_survival_rate_period_length_;
-  double survival_rate_;
   intptr_t promoted_objects_size_;
   double promotion_rate_;
   intptr_t semi_space_copied_object_size_;
   double semi_space_copied_rate_;
-  SurvivalRateTrend previous_survival_rate_trend_;
-  SurvivalRateTrend survival_rate_trend_;
 
-  void set_survival_rate_trend(SurvivalRateTrend survival_rate_trend) {
-    ASSERT(survival_rate_trend != FLUCTUATING);
-    previous_survival_rate_trend_ = survival_rate_trend_;
-    survival_rate_trend_ = survival_rate_trend;
-  }
-
-  SurvivalRateTrend survival_rate_trend() {
-    if (survival_rate_trend_ == STABLE) {
-      return STABLE;
-    } else if (previous_survival_rate_trend_ == STABLE) {
-      return survival_rate_trend_;
-    } else if (survival_rate_trend_ != previous_survival_rate_trend_) {
-      return FLUCTUATING;
-    } else {
-      return survival_rate_trend_;
-    }
-  }
-
-  bool IsStableOrIncreasingSurvivalTrend() {
-    switch (survival_rate_trend()) {
-      case STABLE:
-      case INCREASING:
-        return true;
-      default:
-        return false;
-    }
-  }
-
-  bool IsStableOrDecreasingSurvivalTrend() {
-    switch (survival_rate_trend()) {
-      case STABLE:
-      case DECREASING:
-        return true;
-      default:
-        return false;
-    }
-  }
-
-  bool IsIncreasingSurvivalTrend() {
-    return survival_rate_trend() == INCREASING;
-  }
-
+  // TODO(hpayer): Allocation site pretenuring may make this method obsolete.
+  // Re-visit incremental marking heuristics.
   bool IsHighSurvivalRate() {
     return high_survival_rate_period_length_ > 0;
   }
 
-  bool IsLowSurvivalRate() {
-    return low_survival_rate_period_length_ > 0;
-  }
-
   void SelectScavengingVisitorsTable();
 
   void StartIdleRound() {
     mark_sweeps_since_idle_round_started_ = 0;
   }
 
   void FinishIdleRound() {
     mark_sweeps_since_idle_round_started_ = kMaxMarkSweepsInIdleRound;
     scavenges_since_last_idle_round_ = 0;
   }
@@ skipping 723 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_