After performing scavenge, hint OS that data in from spaces are no more neede...

src/platform-win32.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
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   return true;
 }
 
 
 bool VirtualMemory::Uncommit(void* address, size_t size) {
   ASSERT(IsReserved());
   return VirtualFree(address, size, MEM_DECOMMIT) != FALSE;
 }
 
 
+bool VirtualMemory::Reset(void* address, size_t size, bool is_executable) {
+  int prot = is_executable ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
+  return NULL != VirtualAlloc(address, size, MEM_RESET, PAGE_READWRITE);
+}
+
+
 // ----------------------------------------------------------------------------
 // Win32 thread support.
 
 // Definition of invalid thread handle and id.
 static const HANDLE kNoThread = INVALID_HANDLE_VALUE;
 static const DWORD kNoThreadId = 0;
 
 
 class ThreadHandle::PlatformData : public Malloced {
  public:
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   // Release the thread handles
   CloseHandle(data_->sampler_thread_);
   CloseHandle(data_->profiled_thread_);
 }
 
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal