Dampen old generation allocation limit after scavenge if allocation rate is low.

src/heap/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_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 1158 matching lines @@
   static double HeapGrowingFactor(double gc_speed, double mutator_speed);
 
   // Calculates the allocation limit based on a given growing factor and a
   // given old generation size.
   intptr_t CalculateOldGenerationAllocationLimit(double factor,
                                                  intptr_t old_gen_size);
 
   // Sets the allocation limit to trigger the next full garbage collection.
   void SetOldGenerationAllocationLimit(intptr_t old_gen_size, double gc_speed,
                                        double mutator_speed);
+  // Decreases the allocation limit if the the allocation rate is low.

[Hannes Payer (out of office), 2015/06/16 22:29:22]

This function does not depend on low allocation rate, we check that outside.
Just say here that this function may decrease the allocation limit if the new
limit based on the given parameters is lower than the current limit.

[ulan, 2015/06/17 08:47:45]

Done.

+  void DampenOldGenerationAllocationLimit(intptr_t old_gen_size,
+                                          double gc_speed,
+                                          double mutator_speed);
 
   // Indicates whether inline bump-pointer allocation has been disabled.
   bool inline_allocation_disabled() { return inline_allocation_disabled_; }
 
   // Switch whether inline bump-pointer allocation should be used.
   void EnableInlineAllocation();
   void DisableInlineAllocation();
 
   // Implements the corresponding V8 API function.
   bool IdleNotification(double deadline_in_seconds);
@@ skipping 1637 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_HEAP_H_