74 };
  75 
  76 enum ThreadPriority {        // JLS 20.20.1-3
  77   NoPriority       = -1,     // Initial non-priority value
  78   MinPriority      =  1,     // Minimum priority
  79   NormPriority     =  5,     // Normal (non-daemon) priority
  80   NearMaxPriority  =  9,     // High priority, used for VMThread
  81   MaxPriority      = 10,     // Highest priority, used for WatcherThread
  82                              // ensures that VMThread doesn't starve profiler
  83   CriticalPriority = 11      // Critical thread priority
  84 };
  85 
  86 // Executable parameter flag for os::commit_memory() and
  87 // os::commit_memory_or_exit().
  88 const bool ExecMem = true;
  89 
  90 // Typedef for structured exception handling support
  91 typedef void (*java_call_t)(JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);
  92 
  93 class os: AllStatic {


  94  public:
  95   enum { page_sizes_max = 9 }; // Size of _page_sizes array (8 plus a sentinel)
  96 
  97  private:
  98   static OSThread*          _starting_thread;
  99   static address            _polling_page;
 100   static volatile int32_t * _mem_serialize_page;
 101   static uintptr_t          _serialize_page_mask;
 102  public:
 103   static size_t             _page_sizes[page_sizes_max];
 104 
 105  private:
 106   static void init_page_sizes(size_t default_page_size) {
 107     _page_sizes[0] = default_page_size;
 108     _page_sizes[1] = 0; // sentinel
 109   }
 110 
 111   static char*  pd_reserve_memory(size_t bytes, char* addr = 0,
 112                                size_t alignment_hint = 0);
 113   static char*  pd_attempt_reserve_memory_at(size_t bytes, char* addr);

  74 };
  75 
  76 enum ThreadPriority {        // JLS 20.20.1-3
  77   NoPriority       = -1,     // Initial non-priority value
  78   MinPriority      =  1,     // Minimum priority
  79   NormPriority     =  5,     // Normal (non-daemon) priority
  80   NearMaxPriority  =  9,     // High priority, used for VMThread
  81   MaxPriority      = 10,     // Highest priority, used for WatcherThread
  82                              // ensures that VMThread doesn't starve profiler
  83   CriticalPriority = 11      // Critical thread priority
  84 };
  85 
  86 // Executable parameter flag for os::commit_memory() and
  87 // os::commit_memory_or_exit().
  88 const bool ExecMem = true;
  89 
  90 // Typedef for structured exception handling support
  91 typedef void (*java_call_t)(JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);
  92 
  93 class os: AllStatic {
  94   friend class VMStructs;
  95 
  96  public:
  97   enum { page_sizes_max = 9 }; // Size of _page_sizes array (8 plus a sentinel)
  98 
  99  private:
 100   static OSThread*          _starting_thread;
 101   static address            _polling_page;
 102   static volatile int32_t * _mem_serialize_page;
 103   static uintptr_t          _serialize_page_mask;
 104  public:
 105   static size_t             _page_sizes[page_sizes_max];
 106 
 107  private:
 108   static void init_page_sizes(size_t default_page_size) {
 109     _page_sizes[0] = default_page_size;
 110     _page_sizes[1] = 0; // sentinel
 111   }
 112 
 113   static char*  pd_reserve_memory(size_t bytes, char* addr = 0,
 114                                size_t alignment_hint = 0);
 115   static char*  pd_attempt_reserve_memory_at(size_t bytes, char* addr);