Move most of the implementation of AdjustAmountOfExternalMemory to v8.h

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 4197 matching lines @@
    * by JavaScript objects. V8 uses this to decide when to perform global
    * garbage collections. Registering externally allocated memory will trigger
    * global garbage collections more often than it would otherwise in an attempt
    * to garbage collect the JavaScript objects that keep the externally
    * allocated memory alive.
    *
    * \param change_in_bytes the change in externally allocated memory that is
    *   kept alive by JavaScript objects.
    * \returns the adjusted value.
    */
-  int64_t AdjustAmountOfExternalAllocatedMemory(int64_t change_in_bytes);
+  V8_INLINE int64_t
+      AdjustAmountOfExternalAllocatedMemory(int64_t change_in_bytes);
 
   /**
    * Returns heap profiler for this isolate. Will return NULL until the isolate
    * is initialized.
    */
   HeapProfiler* GetHeapProfiler();
 
   /**
    * Returns CPU profiler for this isolate. Will return NULL unless the isolate
    * is initialized. It is the embedder's responsibility to stop all CPU
@@ skipping 182 matching lines @@
   Isolate();
   Isolate(const Isolate&);
   ~Isolate();
   Isolate& operator=(const Isolate&);
   void* operator new(size_t size);
   void operator delete(void*, size_t);
 
   void SetObjectGroupId(internal::Object** object, UniqueId id);
   void SetReferenceFromGroup(UniqueId id, internal::Object** object);
   void SetReference(internal::Object** parent, internal::Object** child);
+  int64_t SlowAdjustAmountOfExternalAllocatedMemory(int64_t change_in_bytes);
 };
 
 class V8_EXPORT StartupData {
  public:
   enum CompressionAlgorithm {
     kUncompressed,
     kBZip2
   };
 
   const char* data;
@@ skipping 1026 matching lines @@
 };
 
 
 // --- Implementation ---
 
 
 namespace internal {
 
 const int kApiPointerSize = sizeof(void*);  // NOLINT
 const int kApiIntSize = sizeof(int);  // NOLINT
+const int kApiInt64Size = sizeof(int64_t);  // NOLINT
 
 // Tag information for HeapObject.
 const int kHeapObjectTag = 1;
 const int kHeapObjectTagSize = 2;
 const intptr_t kHeapObjectTagMask = (1 << kHeapObjectTagSize) - 1;
 
 // Tag information for Smi.
 const int kSmiTag = 0;
 const int kSmiTagSize = 1;
 const intptr_t kSmiTagMask = (1 << kSmiTagSize) - 1;
@@ skipping 78 matching lines @@
   static const int kJSObjectHeaderSize = 3 * kApiPointerSize;
   static const int kFixedArrayHeaderSize = 2 * kApiPointerSize;
   static const int kContextHeaderSize = 2 * kApiPointerSize;
   static const int kContextEmbedderDataIndex = 75;
   static const int kFullStringRepresentationMask = 0x07;
   static const int kStringEncodingMask = 0x4;
   static const int kExternalTwoByteRepresentationTag = 0x02;
   static const int kExternalAsciiRepresentationTag = 0x06;
 
   static const int kIsolateEmbedderDataOffset = 0 * kApiPointerSize;
-  static const int kIsolateRootsOffset = 5 * kApiPointerSize;
+  static const int kAmountOfExternalAllocatedMemoryOffset =
+      4 * kApiPointerSize;
+  static const int kAmountOfExternalAllocatedMemoryAtLastGlobalGCOffset =
+      kAmountOfExternalAllocatedMemoryOffset + kApiInt64Size;
+  static const int kIsolateRootsOffset =
+      kAmountOfExternalAllocatedMemoryAtLastGlobalGCOffset + kApiInt64Size +
+      kApiPointerSize;
   static const int kUndefinedValueRootIndex = 5;
   static const int kNullValueRootIndex = 7;
   static const int kTrueValueRootIndex = 8;
   static const int kFalseValueRootIndex = 9;
   static const int kEmptyStringRootIndex = 162;
 
+  // The external allocation limit should be below 256 MB on all architectures
+  // to avoid that resource-constrained embedders run low on memory.
+  static const int kExternalAllocationLimit = 192 * 1024 * 1024;
+
   static const int kNodeClassIdOffset = 1 * kApiPointerSize;
   static const int kNodeFlagsOffset = 1 * kApiPointerSize + 3;
   static const int kNodeStateMask = 0xf;
   static const int kNodeStateIsWeakValue = 2;
   static const int kNodeStateIsPendingValue = 3;
   static const int kNodeStateIsNearDeathValue = 4;
   static const int kNodeIsIndependentShift = 4;
   static const int kNodeIsPartiallyDependentShift = 5;
 
   static const int kJSObjectType = 0xbb;
@@ skipping 999 matching lines @@
   return I::GetEmbedderData(this, slot);
 }
 
 
 uint32_t Isolate::GetNumberOfDataSlots() {
   typedef internal::Internals I;
   return I::kNumIsolateDataSlots;
 }
 
 
+int64_t Isolate::AdjustAmountOfExternalAllocatedMemory(
+    int64_t change_in_bytes) {
+#ifndef V8_ENABLE_CHECKS
+  typedef internal::Internals I;
+  int64_t* amount_of_external_allocated_memory =
+      reinterpret_cast<int64_t*>(reinterpret_cast<uint8_t*>(this) +
+                                 I::kAmountOfExternalAllocatedMemoryOffset);
+  int64_t* amount_of_external_allocated_memory_at_last_global_gc =
+      reinterpret_cast<int64_t*>(
+          reinterpret_cast<uint8_t*>(this) +
+          I::kAmountOfExternalAllocatedMemoryAtLastGlobalGCOffset);
+  int64_t amount = *amount_of_external_allocated_memory + change_in_bytes;
+  if (change_in_bytes > 0) {
+    if (amount - *amount_of_external_allocated_memory_at_last_global_gc >
+        I::kExternalAllocationLimit) {
+      // Will likely trigger a GC.
+      return SlowAdjustAmountOfExternalAllocatedMemory(change_in_bytes);
+    }
+  }
+  *amount_of_external_allocated_memory = amount;
+  return *amount_of_external_allocated_memory;
+#else
+  return SlowAdjustAmountOfExternalAllocatedMemory(change_in_bytes);
+#endif
+}
+
+
 template<typename T>
 void Isolate::SetObjectGroupId(const Persistent<T>& object,
                                UniqueId id) {
   TYPE_CHECK(Value, T);
   SetObjectGroupId(reinterpret_cast<v8::internal::Object**>(object.val_), id);
 }
 
 
 template<typename T>
 void Isolate::SetReferenceFromGroup(UniqueId id,
@@ skipping 51 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_