Oilpan: Reduce the reserved size of CallbackStacks

third_party/WebKit/Source/platform/heap/CallbackStack.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/heap/CallbackStack.h"
+#include "wtf/Partitions.h"
 
 namespace blink {
 
+CallbackStack::Block::Block(Block* next, size_t blockSize)
+    : m_blockSize(blockSize)
+{
+    m_buffer = static_cast<Item*>(WTF::Partitions::fastMalloc(blockSize * sizeof(Item), "CallbackStack::Block"));
+    m_limit = &(m_buffer[m_blockSize]);
+    m_current = &(m_buffer[0]);
+    m_next = next;
+    clearUnused();
+}
+
+CallbackStack::Block::~Block()
+{
+    clearUnused();
+    m_limit = nullptr;
+    m_current = nullptr;
+    m_next = nullptr;
+    WTF::Partitions::fastFree(m_buffer);
+}
+
 void CallbackStack::Block::clear()
 {
     m_current = &m_buffer[0];
     m_next = nullptr;
     clearUnused();
 }
 
 void CallbackStack::Block::invokeEphemeronCallbacks(Visitor* visitor)
 {
     // This loop can tolerate entries being added by the callbacks after
@@ skipping 12 matching lines @@
         if (item->object() == object)
             return true;
     }
     return false;
 }
 #endif
 
 void CallbackStack::Block::clearUnused()
 {
 #if ENABLE(ASSERT)
-    for (size_t i = 0; i < blockSize; i++)
+    for (size_t i = 0; i < m_blockSize; i++)
         m_buffer[i] = Item(0, 0);
 #endif
 }
 
-CallbackStack::CallbackStack() : m_first(new Block(0)), m_last(m_first)
+CallbackStack::CallbackStack(size_t reservedStackSize)
+    : m_first(new Block(nullptr, reservedStackSize))
+    , m_last(m_first)
 {
 }
 
 CallbackStack::~CallbackStack()
 {
     clear();
     delete m_first;
     m_first = nullptr;
     m_last = nullptr;
 }
@@ skipping 10 matching lines @@
 }
 
 bool CallbackStack::isEmpty() const
 {
     return hasJustOneBlock() && m_first->isEmptyBlock();
 }
 
 CallbackStack::Item* CallbackStack::allocateEntrySlow()
 {
     ASSERT(!m_first->allocateEntry());
-    m_first = new Block(m_first);
+    m_first = new Block(m_first, m_first->blockSize() * 2);
     return m_first->allocateEntry();
 }
 
 CallbackStack::Item* CallbackStack::popSlow()
 {
     ASSERT(m_first->isEmptyBlock());
 
     for (;;) {
         Block* next = m_first->next();
         if (!next) {
@@ skipping 47 matching lines @@
 {
     for (Block* current = m_first; current; current = current->next()) {
         if (current->hasCallbackForObject(object))
             return true;
     }
     return false;
 }
 #endif
 
 } // namespace blink