Increase the page space growth rate when there is insufficient free space.

runtime/vm/pages.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_PAGES_H_
 #define VM_PAGES_H_
 
 #include "vm/freelist.h"
 #include "vm/globals.h"
 #include "vm/virtual_memory.h"
@@ skipping 100 matching lines @@
                       int heap_growth_rate,
                       int garbage_collection_time_ratio);
   ~PageSpaceController();
 
   bool CanGrowPageSpace(intptr_t size_in_bytes);
 
   // A garbage collection is considered as successful if more than
   // heap_growth_ratio % of memory got deallocated by the garbage collector.
   // In this case garbage collection will be performed next time. Otherwise
   // the heap will grow.
-  void EvaluateGarbageCollection(size_t in_use_before, size_t in_use_after,
+  void EvaluateGarbageCollection(intptr_t in_use_before, intptr_t in_use_after,
                                  int64_t start, int64_t end);
 
   void Enable() {
     is_enabled_ = true;
   }
 
  private:
   bool is_enabled_;
 
   // Heap growth control variable.
   uword grow_heap_;
 
   // If the garbage collector was not able to free more than heap_growth_ratio_
   // memory, then the heap is grown. Otherwise garbage collection is performed.
   int heap_growth_ratio_;
 
+  // The desired percent of heap in-use after a garbage collection.
+  // Equivalent to \frac{100-heap_growth_ratio_}{100}.
+  double desired_utilization_;
+
   // Number of pages we grow.
   int heap_growth_rate_;
 
   // If the relative GC time stays below garbage_collection_time_ratio_
   // garbage collection can be performed.
   int garbage_collection_time_ratio_;
 
   PageSpaceGarbageCollectionHistory history_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PageSpaceController);
@@ skipping 96 matching lines @@
   bool sweeping_;
 
   PageSpaceController page_space_controller_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PageSpace);
 };
 
 }  // namespace dart
 
 #endif  // VM_PAGES_H_