Fix x64 port by using 32 pages per chunk.

TBR=ager@chromium.org
Review URL: http://codereview.chromium.org/195038

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2860 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/spaces.h

@@ -447,7 +447,11 @@ class MemoryAllocator : public AllStatic {
   static const int kMaxNofChunks = 1 << Page::kPageSizeBits;
   // If a chunk has at least 16 pages, the maximum heap size is about
   // 8K * 8K * 16 = 1G bytes.
+#ifdef V8_TARGET_ARCH_X64
+  static const int kPagesPerChunk = 32;
+#else
   static const int kPagesPerChunk = 16;
+#endif
   static const int kChunkSize = kPagesPerChunk * Page::kPageSize;
 
  private: