--- a/hotspot/src/share/vm/runtime/os.hpp	Tue Aug 05 14:18:44 2014 +0000
+++ b/hotspot/src/share/vm/runtime/os.hpp	Thu Aug 07 12:18:58 2014 -0700
@@ -65,6 +65,8 @@
 class Event;
 class DLL;
 class FileHandle;
+class NativeCallStack;
+
 template<class E> class GrowableArray;
 
 // %%%%% Moved ThreadState, START_FN, OSThread to new osThread.hpp. -- Rose
@@ -96,9 +98,11 @@
 // Typedef for structured exception handling support
 typedef void (*java_call_t)(JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);
 
+class MallocTracker;
+
 class os: AllStatic {
   friend class VMStructs;
-
+  friend class MallocTracker;
  public:
   enum { page_sizes_max = 9 }; // Size of _page_sizes array (8 plus a sentinel)
 
@@ -160,7 +164,10 @@
   // Override me as needed
   static int    file_name_strcmp(const char* s1, const char* s2);
 
+  // get/unset environment variable
   static bool getenv(const char* name, char* buffer, int len);
+  static bool unsetenv(const char* name);
+
   static bool have_special_privileges();
 
   static jlong  javaTimeMillis();
@@ -207,8 +214,13 @@
 
   // Interface for detecting multiprocessor system
   static inline bool is_MP() {
+#if !INCLUDE_NMT
     assert(_processor_count > 0, "invalid processor count");
     return _processor_count > 1 || AssumeMP;
+#else
+    // NMT needs atomic operations before this initialization.
+    return true;
+#endif
   }
   static julong available_memory();
   static julong physical_memory();
@@ -635,12 +647,20 @@
   static void* thread_local_storage_at(int index);
   static void  free_thread_local_storage(int index);
 
-  // Stack walk
-  static address get_caller_pc(int n = 0);
+  // Retrieve native stack frames.
+  // Parameter:
+  //   stack:  an array to storage stack pointers.
+  //   frames: size of above array.
+  //   toSkip: number of stack frames to skip at the beginning.
+  // Return: number of stack frames captured.
+  static int get_native_stack(address* stack, int size, int toSkip = 0);
 
   // General allocation (must be MT-safe)
-  static void* malloc  (size_t size, MEMFLAGS flags, address caller_pc = 0);
-  static void* realloc (void *memblock, size_t size, MEMFLAGS flags, address caller_pc = 0);
+  static void* malloc  (size_t size, MEMFLAGS flags, const NativeCallStack& stack);
+  static void* malloc  (size_t size, MEMFLAGS flags);
+  static void* realloc (void *memblock, size_t size, MEMFLAGS flag, const NativeCallStack& stack);
+  static void* realloc (void *memblock, size_t size, MEMFLAGS flag);
+
   static void  free    (void *memblock, MEMFLAGS flags = mtNone);
   static bool  check_heap(bool force = false);      // verify C heap integrity
   static char* strdup(const char *, MEMFLAGS flags = mtInternal);  // Like strdup