TSO.h 6.74 KB
Newer Older
1
/* -----------------------------------------------------------------------------
2
 *
Simon Marlow's avatar
Simon Marlow committed
3
 * (c) The GHC Team, 1998-2009
4 5 6 7 8
 *
 * The definitions for Thread State Objects.
 *
 * ---------------------------------------------------------------------------*/

Simon Marlow's avatar
Simon Marlow committed
9 10
#ifndef RTS_STORAGE_TSO_H
#define RTS_STORAGE_TSO_H
11

12 13 14
/*
 * PROFILING info in a TSO
 */
15 16 17 18
typedef struct {
  CostCentreStack *CCCS;	/* thread's current CCS */
} StgTSOProfInfo;

19
/*
20
 * There is no TICKY info in a TSO at this time.
21
 */
22 23

/*
ken's avatar
ken committed
24
 * Thread IDs are 32 bits.
25
 */
sof's avatar
sof committed
26
typedef StgWord32 StgThreadID;
27

28 29
#define tsoDirty(tso)  ((tso)->flags & TSO_DIRTY)
#define tsoLocked(tso) ((tso)->flags & TSO_LOCKED)
30

31
/*
32 33 34
 * Type returned after running a thread.  Values of this type
 * include HeapOverflow, StackOverflow etc.  See Constants.h for the
 * full list.
35
 */
36
typedef unsigned int StgThreadReturnCode;
37

38
#if defined(mingw32_HOST_OS)
sof's avatar
sof committed
39
/* results from an async I/O request + its request ID. */
sof's avatar
sof committed
40 41 42 43 44 45 46
typedef struct {
  unsigned int reqID;
  int          len;
  int          errCode;
} StgAsyncIOResult;
#endif

47
/* Reason for thread being blocked. See comment above struct StgTso_. */
48 49
typedef union {
  StgClosure *closure;
50
  struct StgTSO_ *tso;
51
  StgInt fd;	/* StgInt instead of int, so that it's the same size as the ptrs */
52
#if defined(mingw32_HOST_OS)
sof's avatar
sof committed
53
  StgAsyncIOResult *async_result;
sof's avatar
sof committed
54
#endif
55
  StgWord target;
56 57
} StgTSOBlockInfo;

58

59 60 61 62 63 64
/*
 * TSOs live on the heap, and therefore look just like heap objects.
 * Large TSOs will live in their own "block group" allocated by the
 * storage manager, and won't be copied during garbage collection.
 */

65
/*
66 67 68 69 70 71 72
 * Threads may be blocked for several reasons.  A blocked thread will
 * have the reason in the why_blocked field of the TSO, and some
 * further info (such as the closure the thread is blocked on, or the
 * file descriptor if the thread is waiting on I/O) in the block_info
 * field.
 */

73
typedef struct StgTSO_ {
74 75
    StgHeader               header;

76 77 78 79 80 81 82 83 84 85 86 87 88 89 90
    /* The link field, for linking threads together in lists (e.g. the
       run queue on a Capability.
    */
    struct StgTSO_*         _link;
    /*
       NOTE!!!  do not modify _link directly, it is subject to
       a write barrier for generational GC.  Instead use the
       setTSOLink() function.  Exceptions to this rule are:

       * setting the link field to END_TSO_QUEUE
       * putting a TSO on the blackhole_queue
       * setting the link field of the currently running TSO, as it
         will already be dirty.
    */

91 92 93 94 95 96 97 98 99 100 101 102
    struct StgTSO_*         global_link;    /* Links all threads together */
    
    StgWord16               what_next;      /* Values defined in Constants.h */
    StgWord16               why_blocked;    /* Values defined in Constants.h */
    StgWord32               flags;
    StgTSOBlockInfo         block_info;
    StgThreadID             id;
    int                     saved_errno;
    struct Task_*           bound;
    struct Capability_*     cap;
    struct StgTRecHeader_ * trec;       /* STM transaction record */

103
    /*
104 105 106 107 108 109
       A list of threads blocked on this TSO waiting to throw
       exceptions.  In order to access this field, the TSO must be
       locked using lockClosure/unlockClosure (see SMP.h).
    */
    struct StgTSO_ *        blocked_exceptions;

110
#ifdef TICKY_TICKY
111
    /* TICKY-specific stuff would go here. */
112 113
#endif
#ifdef PROFILING
114
    StgTSOProfInfo prof;
115
#endif
116 117 118
#ifdef mingw32_HOST_OS
    StgWord32 saved_winerror;
#endif
119

120 121 122 123 124 125
    /* The thread stack... */
    StgWord32	       stack_size;     /* stack size in *words* */
    StgWord32          max_stack_size; /* maximum stack size in *words* */
    StgPtr             sp;
    
    StgWord            stack[FLEXIBLE_ARRAY];
Simon Marlow's avatar
Simon Marlow committed
126
} *StgTSOPtr;
127

128 129 130 131
/* -----------------------------------------------------------------------------
   functions
   -------------------------------------------------------------------------- */

Simon Marlow's avatar
Simon Marlow committed
132 133
void dirty_TSO  (Capability *cap, StgTSO *tso);
void setTSOLink (Capability *cap, StgTSO *tso, StgTSO *target);
134

135 136 137 138 139 140 141 142 143 144 145 146 147 148 149
/* -----------------------------------------------------------------------------
   Invariants:

   An active thread has the following properties:

      tso->stack < tso->sp < tso->stack+tso->stack_size
      tso->stack_size <= tso->max_stack_size
      
      RESERVED_STACK_WORDS is large enough for any heap-check or
      stack-check failure.

      The size of the TSO struct plus the stack is either
        (a) smaller than a block, or
	(b) a multiple of BLOCK_SIZE

150
	tso->why_blocked       tso->block_info      location
151 152 153
        ----------------------------------------------------------------------
	NotBlocked             NULL                 runnable_queue, or running
	
Simon Marlow's avatar
Simon Marlow committed
154
        BlockedOnBlackHole     the BLACKHOLE        blackhole_queue
155 156
	
        BlockedOnMVar          the MVAR             the MVAR's queue
157 158

	BlockedOnSTM           END_TSO_QUEUE        STM wait queue(s)
159 160 161 162 163 164
	
        BlockedOnException     the TSO              TSO->blocked_exception

        BlockedOnRead          NULL                 blocked_queue
        BlockedOnWrite         NULL		    blocked_queue
        BlockedOnDelay         NULL                 blocked_queue
165 166
	BlockedOnGA            closure TSO blocks on   BQ of that closure
	BlockedOnGA_NoSend     closure TSO blocks on   BQ of that closure
167 168

      tso->link == END_TSO_QUEUE, if the thread is currently running.
169 170 171

   A zombie thread has the following properties:
      
172
      tso->what_next == ThreadComplete or ThreadKilled
173 174 175
      tso->link     ==  (could be on some queue somewhere)
      tso->su       ==  tso->stack + tso->stack_size
      tso->sp       ==  tso->stack + tso->stack_size - 1 (i.e. top stack word)
176 177
      tso->sp[0]    ==  return value of thread, if what_next == ThreadComplete,
                        exception             , if what_next == ThreadKilled
178 179 180 181

      (tso->sp is left pointing at the top word on the stack so that
      the return value or exception will be retained by a GC).

182 183
   The 2 cases BlockedOnGA and BlockedOnGA_NoSend are needed in a GUM
   setup only. They mark a TSO that has entered a FETCH_ME or
184
   FETCH_ME_BQ closure, respectively; only the first TSO hitting the
185 186 187 188
   closure will send a Fetch message.
   Currently we have no separate code for blocking on an RBH; we use the
   BlockedOnBlackHole case for that.   -- HWL

189
 ---------------------------------------------------------------------------- */
190 191 192 193 194 195 196 197 198

/* Workaround for a bug/quirk in gcc on certain architectures.
 * symptom is that (&tso->stack - &tso->header) /=  sizeof(StgTSO)
 * in other words, gcc pads the structure at the end.
 */

extern StgTSO dummy_tso;

#define TSO_STRUCT_SIZE \
199
   ((char *)&dummy_tso.stack - (char *)&dummy_tso.header)
200 201 202

#define TSO_STRUCT_SIZEW (TSO_STRUCT_SIZE / sizeof(W_))

203 204 205
/* this is the NIL ptr for a TSO queue (e.g. runnable queue) */
#define END_TSO_QUEUE  ((StgTSO *)(void*)&stg_END_TSO_QUEUE_closure)

Simon Marlow's avatar
Simon Marlow committed
206
#endif /* RTS_STORAGE_TSO_H */