Move most of the implementation of AdjustAmountOfExternalMemory to v8.h

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index b1da55e2c5ee0d2cf566c976b95dde2e0396a27b..0c049bda6cae648ef389b49961aa87f398a0b0de 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -4215,7 +4215,8 @@ class V8_EXPORT Isolate {
    *   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
@@ -4418,6 +4419,7 @@ class V8_EXPORT Isolate {
   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 {
@@ -5464,6 +5466,7 @@ 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;
@@ -5562,7 +5565,11 @@ class Internals {
   static const int kExternalAsciiRepresentationTag = 0x06;
 
   static const int kIsolateEmbedderDataOffset = 0 * kApiPointerSize;
-  static const int kIsolateRootsOffset = 5 * kApiPointerSize;
+  static const int kAmountOfExternalAllocatedMemoryOffset = 5 * kApiPointerSize;
+  static const int kAmountOfExternalAllocatedMemoryAtLastGlobalGCOffset =
+      5 * kApiPointerSize + kApiInt64Size;
+  static const int kIsolateRootsOffset =
+      5 * kApiPointerSize + 2 * kApiInt64Size;
   static const int kUndefinedValueRootIndex = 5;
   static const int kNullValueRootIndex = 7;
   static const int kTrueValueRootIndex = 8;
@@ -6588,6 +6595,49 @@ uint32_t Isolate::GetNumberOfDataSlots() {
 }
 
 
+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) {
+    // Avoid overflow.
+    if (amount > *amount_of_external_allocated_memory) {
+      if (amount - *amount_of_external_allocated_memory_at_last_global_gc >
+          192 * 1024 * 1024) {

[Hannes Payer (out of office), 2014/06/04 11:24:49]

192? Please don't use a hard-coded value here.

[jochen (gone - plz use gerrit), 2014/06/04 11:41:24]

Done.

+        // Will likely trigger a GC.
+        return SlowAdjustAmountOfExternalAllocatedMemory(change_in_bytes);
+      }
+      *amount_of_external_allocated_memory = amount;
+    } else {
+      // Give up and reset the counters in case of an overflow.
+      *amount_of_external_allocated_memory = 0;
+      *amount_of_external_allocated_memory_at_last_global_gc = 0;
+    }
+  } else {
+    // Avoid underflow.
+    if (amount >= 0) {
+      *amount_of_external_allocated_memory = amount;
+    } else {
+      // Give up and reset the counters in case of an underflow.
+      *amount_of_external_allocated_memory = 0;
+      *amount_of_external_allocated_memory_at_last_global_gc = 0;
+    }
+  }
+  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) {