Make sure that idle scavenges are just performed when enough objects are allocated in new space.

src/heap/gc-idle-time-handler.h

 // Copyright 2014 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_GC_IDLE_TIME_HANDLER_H_
 #define V8_HEAP_GC_IDLE_TIME_HANDLER_H_
 
 #include "src/globals.h"
 
 namespace v8 {
@@ skipping 118 matching lines @@
   static const size_t kMaxFrameRenderingIdleTime = 17;
 
   // We conservatively assume that in the next kTimeUntilNextIdleEvent ms
   // no idle notification happens.
   static const size_t kTimeUntilNextIdleEvent = 100;
 
   // If we haven't recorded any scavenger events yet, we use a conservative
   // lower bound for the scavenger speed.
   static const size_t kInitialConservativeScavengeSpeed = 100 * KB;
 
+  // The minimum size of allocated new space objects to trigger a scavenge.
+  static const size_t kMinimumNewSpaceSizeToPerformScavenge = MB / 2;
+
   // If contexts are disposed at a higher rate a full gc is triggered.
   static const double kHighContextDisposalRate;
 
   // Incremental marking step time.
   static const size_t kIncrementalMarkingStepTimeInMs = 1;
 
   static const size_t kMinTimeForOverApproximatingWeakClosureInMs;
 
   // The number of idle MarkCompact GCs to perform before transitioning to
   // the kDone mode.
@@ skipping 96 matching lines @@
 
   Mode mode_;
 
   DISALLOW_COPY_AND_ASSIGN(GCIdleTimeHandler);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_GC_IDLE_TIME_HANDLER_H_