[heap] Activate memory reducer on external memory activity.

include/v8.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.
 
 /** \mainpage V8 API Reference Guide
  *
  * V8 is Google's open source JavaScript engine.
  *
  * This set of documents provides reference material generated from the
  * V8 header file, include/v8.h.
@@ skipping 7571 matching lines @@
   void* operator new(size_t size) = delete;
   void* operator new[](size_t size) = delete;
   void operator delete(void*, size_t) = delete;
   void operator delete[](void*, size_t) = delete;
 
  private:
   template <class K, class V, class Traits>
   friend class PersistentValueMapBase;
 
   void ReportExternalAllocationLimitReached();
+  void CheckMemoryPressure();
 };
 
 class V8_EXPORT StartupData {
  public:
   const char* data;
   int raw_size;
 };
 
 
 /**
@@ skipping 1207 matching lines @@
   static const int kContextEmbedderDataIndex = 5;
   static const int kFullStringRepresentationMask = 0x0f;
   static const int kStringEncodingMask = 0x8;
   static const int kExternalTwoByteRepresentationTag = 0x02;
   static const int kExternalOneByteRepresentationTag = 0x0a;
 
   static const int kIsolateEmbedderDataOffset = 0 * kApiPointerSize;
   static const int kExternalMemoryOffset = 4 * kApiPointerSize;
   static const int kExternalMemoryLimitOffset =
       kExternalMemoryOffset + kApiInt64Size;
+  static const int kExternalMemoryAtLastMarkCompactOffset =
+      kExternalMemoryLimitOffset + kApiInt64Size;
   static const int kIsolateRootsOffset = kExternalMemoryLimitOffset +
                                          kApiInt64Size + kApiInt64Size +
                                          kApiPointerSize + kApiPointerSize;
   static const int kUndefinedValueRootIndex = 4;
   static const int kTheHoleValueRootIndex = 5;
   static const int kNullValueRootIndex = 6;
   static const int kTrueValueRootIndex = 7;
   static const int kFalseValueRootIndex = 8;
   static const int kEmptyStringRootIndex = 9;
 
@@ skipping 1197 matching lines @@
 
 
 uint32_t Isolate::GetNumberOfDataSlots() {
   typedef internal::Internals I;
   return I::kNumIsolateDataSlots;
 }
 
 
 int64_t Isolate::AdjustAmountOfExternalAllocatedMemory(
     int64_t change_in_bytes) {
+  const int64_t kMemoryReducerActivationLimit = 1024 * 1024;
   typedef internal::Internals I;
   int64_t* external_memory = reinterpret_cast<int64_t*>(
       reinterpret_cast<uint8_t*>(this) + I::kExternalMemoryOffset);
   const int64_t external_memory_limit = *reinterpret_cast<int64_t*>(
       reinterpret_cast<uint8_t*>(this) + I::kExternalMemoryLimitOffset);
+  int64_t* external_memory_at_last_mc =
+      reinterpret_cast<int64_t*>(reinterpret_cast<uint8_t*>(this) +
+                                 I::kExternalMemoryAtLastMarkCompactOffset);
   const int64_t amount = *external_memory + change_in_bytes;
+
   *external_memory = amount;
+
+  int64_t allocation_diff_since_last_mc =
+      *external_memory_at_last_mc - *external_memory;
+  allocation_diff_since_last_mc = allocation_diff_since_last_mc < 0
+                                      ? -allocation_diff_since_last_mc
+                                      : allocation_diff_since_last_mc;
+  if (allocation_diff_since_last_mc > kMemoryReducerActivationLimit) {
+    CheckMemoryPressure();
+  }
+
   if (change_in_bytes > 0 && amount > external_memory_limit) {
     ReportExternalAllocationLimitReached();
   }
   return *external_memory;
 }
 
 Local<Value> Context::GetEmbedderData(int index) {
 #ifndef V8_ENABLE_CHECKS
   typedef internal::Object O;
   typedef internal::HeapObject HO;
@@ skipping 127 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // INCLUDE_V8_H_