65   volatile intptr_t FullWord ;
  66   volatile void * Address ;
  67   volatile jbyte Bytes [sizeof(intptr_t)] ;
  68 } ;
  69 
  70 // Endian-ness ... index of least-significant byte in SplitWord.Bytes[]
  71 #ifdef VM_LITTLE_ENDIAN
  72  #define _LSBINDEX 0
  73 #else
  74  #define _LSBINDEX (sizeof(intptr_t)-1)
  75 #endif
  76 
  77 class ParkEvent ;
  78 
  79 // See orderAccess.hpp.  We assume throughout the VM that mutex lock and
  80 // try_lock do fence-lock-acquire, and that unlock does a release-unlock,
  81 // *in that order*.  If their implementations change such that these
  82 // assumptions are violated, a whole lot of code will break.
  83 
  84 // The default length of monitor name is chosen to be 64 to avoid false sharing.
  85 static const int MONITOR_NAME_LEN = 64;
  86 
  87 class Monitor : public CHeapObj<mtInternal> {
  88 
  89  public:
  90   // A special lock: Is a lock where you are guaranteed not to block while you are
  91   // holding it, i.e., no vm operation can happen, taking other locks, etc.
  92   // NOTE: It is critical that the rank 'special' be the lowest (earliest)
  93   // (except for "event"?) for the deadlock detection to work correctly.
  94   // The rank native is only for use in Mutex's created by JVM_RawMonitorCreate,
  95   // which being external to the VM are not subject to deadlock detection.
  96   // The rank safepoint is used only for synchronization in reaching a
  97   // safepoint and leaving a safepoint.  It is only used for the Safepoint_lock
  98   // currently.  While at a safepoint no mutexes of rank safepoint are held
  99   // by any thread.
 100   // The rank named "leaf" is probably historical (and should
 101   // be changed) -- mutexes of this rank aren't really leaf mutexes
 102   // at all.
 103   enum lock_types {
 104        event,
 105        special,

  65   volatile intptr_t FullWord ;
  66   volatile void * Address ;
  67   volatile jbyte Bytes [sizeof(intptr_t)] ;
  68 } ;
  69 
  70 // Endian-ness ... index of least-significant byte in SplitWord.Bytes[]
  71 #ifdef VM_LITTLE_ENDIAN
  72  #define _LSBINDEX 0
  73 #else
  74  #define _LSBINDEX (sizeof(intptr_t)-1)
  75 #endif
  76 
  77 class ParkEvent ;
  78 
  79 // See orderAccess.hpp.  We assume throughout the VM that mutex lock and
  80 // try_lock do fence-lock-acquire, and that unlock does a release-unlock,
  81 // *in that order*.  If their implementations change such that these
  82 // assumptions are violated, a whole lot of code will break.
  83 
  84 // The default length of monitor name is chosen to be 64 to avoid false sharing.
  85 static const int MONITOR_NAME_LEN = 64 S390_ONLY(+192);
  86 
  87 class Monitor : public CHeapObj<mtInternal> {
  88 
  89  public:
  90   // A special lock: Is a lock where you are guaranteed not to block while you are
  91   // holding it, i.e., no vm operation can happen, taking other locks, etc.
  92   // NOTE: It is critical that the rank 'special' be the lowest (earliest)
  93   // (except for "event"?) for the deadlock detection to work correctly.
  94   // The rank native is only for use in Mutex's created by JVM_RawMonitorCreate,
  95   // which being external to the VM are not subject to deadlock detection.
  96   // The rank safepoint is used only for synchronization in reaching a
  97   // safepoint and leaving a safepoint.  It is only used for the Safepoint_lock
  98   // currently.  While at a safepoint no mutexes of rank safepoint are held
  99   // by any thread.
 100   // The rank named "leaf" is probably historical (and should
 101   // be changed) -- mutexes of this rank aren't really leaf mutexes
 102   // at all.
 103   enum lock_types {
 104        event,
 105        special,