Allow Oilpan heap objects account for their external allocations.

Source/core/dom/Text.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 24 matching lines @@
 #include "core/events/ScopedEventQueue.h"
 #include "core/layout/svg/LayoutSVGInlineText.h"
 #include "core/rendering/RenderCombineText.h"
 #include "core/rendering/RenderText.h"
 #include "core/svg/SVGForeignObjectElement.h"
 #include "wtf/text/CString.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace blink {
 
+#if ENABLE(OILPAN)
+namespace {
+// If the external string kept by a Text node exceed this threshold length,
+// Oilpan is informed. External allocation amounts owned by heap objects are
+// taken into account when scheduling urgent Oilpan GCs.
+//
+// FIXME: having only Text nodes with strings above an ad-hoc local threshold
+// influence Oilpan's GC behavior isn't a satisfactory long-term solution.
+// But code that allocates a lot of Text nodes in tight loops, and not much more,
+// we do have to trigger Oilpan GCs to avoid PartitionAlloc OOMs. The accounting
+// does add overhead on the allocation of every Text node however, so for now, only
+// register those above the given threshold. TBC.
+const size_t stringLengthThreshold = 256;
+
+enum RegistrationMode { AsNew, AsAlive };
+
+void registerExternalAllocation(size_t length, RegistrationMode mode)

[haraken, 2015/02/23 14:59:08]

Nit: I'd slightly prefer having two methods for this instead of adding an enum.

increaseExternallyAllocatedBytesIfNeeded(length);
increaseExternallyAllocatedBytesAliveIfNeeded(length);

[sof, 2015/02/23 15:56:07]

Done.

+{
+    if (length > stringLengthThreshold) {
+        if (mode == AsNew)
+            Heap::increaseExternallyAllocatedBytes(length);
+        else
+            Heap::increaseExternallyAllocatedBytesAlive(length);
+    }
+}
+
+} // namespace
+#endif
+
 PassRefPtrWillBeRawPtr<Text> Text::create(Document& document, const String& data)
 {
+#if ENABLE(OILPAN)
+    registerExternalAllocation(data.length(), AsNew);
+#endif
     return adoptRefWillBeNoop(new Text(document, data, CreateText));
 }
 
 PassRefPtrWillBeRawPtr<Text> Text::createEditingText(Document& document, const String& data)
 {
+#if ENABLE(OILPAN)
+    registerExternalAllocation(data.length(), AsNew);
+#endif
     return adoptRefWillBeNoop(new Text(document, data, CreateEditingText));
 }
 
 PassRefPtrWillBeRawPtr<Node> Text::mergeNextSiblingNodesIfPossible()
 {
     RefPtrWillBeRawPtr<Node> protect(this);
 
     // Remove empty text nodes.
     if (!length()) {
         // Care must be taken to get the next node before removing the current node.
@@ skipping 339 matching lines @@
         return;
     }
     textRenderer->setTextWithOffset(dataImpl(), offsetOfReplacedData, lengthOfReplacedData);
 }
 
 PassRefPtrWillBeRawPtr<Text> Text::cloneWithData(const String& data)
 {
     return create(document(), data);
 }
 
+void Text::trace(Visitor* visitor)
+{
+#if ENABLE(OILPAN)
+    registerExternalAllocation(m_data.length(), AsAlive);
+#endif
+    CharacterData::trace(visitor);
+}
+
 #ifndef NDEBUG
 void Text::formatForDebugger(char *buffer, unsigned length) const
 {
     StringBuilder result;
     String s;
 
     result.append(nodeName());
 
     s = data();
     if (s.length() > 0) {
         if (result.length())
             result.appendLiteral("; ");
         result.appendLiteral("value=");
         result.append(s);
     }
 
     strncpy(buffer, result.toString().utf8().data(), length - 1);
 }
 #endif
 
 } // namespace blink