Fix used vs. capacity growth computation mismatch.

runtime/vm/pages.cc

 // Copyright (c) 2012, 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.
 
 #include "vm/pages.h"
 
 #include "platform/assert.h"
 #include "vm/compiler_stats.h"
 #include "vm/gc_marker.h"
 #include "vm/gc_sweeper.h"
 #include "vm/object.h"
 #include "vm/virtual_memory.h"
 
 namespace dart {
 
-DEFINE_FLAG(int, heap_growth_space_ratio, 10,
+DEFINE_FLAG(int, heap_growth_space_ratio, 20,
             "The desired maximum percentage of free space after GC");
 DEFINE_FLAG(int, heap_growth_time_ratio, 3,
             "The desired maximum percentage of time spent in GC");
 DEFINE_FLAG(int, heap_growth_rate, 4,
             "The size the heap is grown, in heap pages");
 DEFINE_FLAG(bool, print_free_list_before_gc, false,
             "Print free list statistics before a GC");
 DEFINE_FLAG(bool, print_free_list_after_gc, false,
             "Print free list statistics after a GC");
 DEFINE_FLAG(bool, collect_code, true,
@@ skipping 658 matching lines @@
       (collected_garbage_ratio >= heap_growth_ratio_);
   int garbage_collection_time_fraction =
       history_.GarbageCollectionTimeFraction();
   bool enough_free_time =
       (garbage_collection_time_fraction <= garbage_collection_time_ratio_);
 
   Heap* heap = Isolate::Current()->heap();
   if (enough_free_space && enough_free_time) {
     grow_heap_ = 0;
   } else {
-    intptr_t growth_target = static_cast<intptr_t>(
+    intptr_t used_target = static_cast<intptr_t>(
         after_total_in_words /  desired_utilization_);
-    intptr_t growth_in_words = Utils::RoundUp(
-        growth_target - after_total_in_words,
-        PageSpace::kPageSizeInWords);
-    int growth_in_pages =
-        growth_in_words / PageSpace::kPageSizeInWords;
-    grow_heap_ = Utils::Maximum(growth_in_pages, heap_growth_rate_);
-    heap->RecordData(PageSpace::kPageGrowth, growth_in_pages);
+    intptr_t capacity_growth_in_words =
+      Utils::RoundUp(Utils::Maximum(static_cast<intptr_t>(0),
+                                    used_target - after.capacity_in_words),
+                       PageSpace::kPageSizeInWords);
+    int capacity_growth_in_pages =
+        capacity_growth_in_words / PageSpace::kPageSizeInWords;
+    grow_heap_ = Utils::Maximum(capacity_growth_in_pages, heap_growth_rate_);
+    heap->RecordData(PageSpace::kPageGrowth, capacity_growth_in_pages);
   }
   heap->RecordData(PageSpace::kGarbageRatio, collected_garbage_ratio);
   heap->RecordData(PageSpace::kGCTimeFraction,
                    garbage_collection_time_fraction);
   heap->RecordData(PageSpace::kAllowedGrowth, grow_heap_);
   last_usage_ = after;
 }
 
 
 PageSpaceGarbageCollectionHistory::PageSpaceGarbageCollectionHistory()
@@ skipping 33 matching lines @@
     return 0;
   } else {
     ASSERT(total_time >= gc_time);
     int result= static_cast<int>((static_cast<double>(gc_time) /
                              static_cast<double>(total_time)) * 100);
     return result;
   }
 }
 
 }  // namespace dart