1 /* -----------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-1999
5 * The definitions for Thread State Objects.
7 * ---------------------------------------------------------------------------*/
13 #define TSO_MAGIC 4321
36 * GRAN: We distinguish between the various classes of threads in
46 * PROFILING info in a TSO
49 CostCentreStack *CCCS; /* thread's current CCS */
55 typedef StgTSOStatBuf StgTSOParInfo;
61 StgThreadPriority priority;
62 StgInt revalTid; /* ToDo: merge both into 1 word */
69 typedef StgTSOStatBuf StgTSOGranInfo;
72 * There is no TICKY info in a TSO at this time.
76 * Thread IDs are 32 bits.
78 typedef StgWord32 StgThreadID;
81 * Type returned after running a thread. Values of this type
82 * include HeapOverflow, StackOverflow etc. See Constants.h for the
85 typedef unsigned int StgThreadReturnCode;
87 #if defined(mingw32_HOST_OS)
88 /* results from an async I/O request + its request ID. */
99 StgInt fd; /* StgInt instead of int, so that it's the same size as the ptrs */
100 #if defined(mingw32_HOST_OS)
101 StgAsyncIOResult *async_result;
107 * TSOs live on the heap, and therefore look just like heap objects.
108 * Large TSOs will live in their own "block group" allocated by the
109 * storage manager, and won't be copied during garbage collection.
113 * Threads may be blocked for several reasons. A blocked thread will
114 * have the reason in the why_blocked field of the TSO, and some
115 * further info (such as the closure the thread is blocked on, or the
116 * file descriptor if the thread is waiting on I/O) in the block_info
120 typedef struct StgTSO_ {
123 struct StgTSO_* link; /* Links threads onto blocking queues */
124 struct StgTSO_* global_link; /* Links all threads together */
126 StgWord16 what_next; /* Values defined in Constants.h */
127 StgWord16 why_blocked; /* Values defined in Constants.h */
128 StgTSOBlockInfo block_info;
129 struct StgTSO_* blocked_exceptions;
132 struct Task_* bound; // non-NULL for a bound thread
133 struct StgTRecHeader_ *trec; /* STM transaction record */
136 /* TICKY-specific stuff would go here. */
151 /* The thread stack... */
152 StgWord stack_size; /* stack size in *words* */
153 StgWord max_stack_size; /* maximum stack size in *words* */
156 StgWord stack[FLEXIBLE_ARRAY];
159 /* -----------------------------------------------------------------------------
162 An active thread has the following properties:
164 tso->stack < tso->sp < tso->stack+tso->stack_size
165 tso->stack_size <= tso->max_stack_size
167 RESERVED_STACK_WORDS is large enough for any heap-check or
170 The size of the TSO struct plus the stack is either
171 (a) smaller than a block, or
172 (b) a multiple of BLOCK_SIZE
174 tso->why_blocked tso->block_info location
175 ----------------------------------------------------------------------
176 NotBlocked NULL runnable_queue, or running
178 BlockedOnBlackHole the BLACKHOLE_BQ the BLACKHOLE_BQ's queue
180 BlockedOnMVar the MVAR the MVAR's queue
182 BlockedOnSTM END_TSO_QUEUE STM wait queue(s)
184 BlockedOnException the TSO TSO->blocked_exception
186 BlockedOnRead NULL blocked_queue
187 BlockedOnWrite NULL blocked_queue
188 BlockedOnDelay NULL blocked_queue
189 BlockedOnGA closure TSO blocks on BQ of that closure
190 BlockedOnGA_NoSend closure TSO blocks on BQ of that closure
192 tso->link == END_TSO_QUEUE, if the thread is currently running.
194 A zombie thread has the following properties:
196 tso->what_next == ThreadComplete or ThreadKilled
197 tso->link == (could be on some queue somewhere)
198 tso->su == tso->stack + tso->stack_size
199 tso->sp == tso->stack + tso->stack_size - 1 (i.e. top stack word)
200 tso->sp[0] == return value of thread, if what_next == ThreadComplete,
201 exception , if what_next == ThreadKilled
203 (tso->sp is left pointing at the top word on the stack so that
204 the return value or exception will be retained by a GC).
206 tso->blocked_exceptions is either:
208 NULL if async exceptions are unblocked.
210 END_TSO_QUEUE if async exceptions are blocked, but no threads
211 are currently waiting to deliver.
213 (StgTSO *)tso if threads are currently awaiting delivery of
214 exceptions to this thread.
216 The 2 cases BlockedOnGA and BlockedOnGA_NoSend are needed in a GUM
217 setup only. They mark a TSO that has entered a FETCH_ME or
218 FETCH_ME_BQ closure, respectively; only the first TSO hitting the
219 closure will send a Fetch message.
220 Currently we have no separate code for blocking on an RBH; we use the
221 BlockedOnBlackHole case for that. -- HWL
223 ---------------------------------------------------------------------------- */
225 /* Workaround for a bug/quirk in gcc on certain architectures.
226 * symptom is that (&tso->stack - &tso->header) /= sizeof(StgTSO)
227 * in other words, gcc pads the structure at the end.
230 extern StgTSO dummy_tso;
232 #define TSO_STRUCT_SIZE \
233 ((char *)&dummy_tso.stack - (char *)&dummy_tso.header)
235 #define TSO_STRUCT_SIZEW (TSO_STRUCT_SIZE / sizeof(W_))
238 /* this is the NIL ptr for a TSO queue (e.g. runnable queue) */
240 #define END_TSO_QUEUE (stg_END_TSO_QUEUE_closure)
242 #define END_TSO_QUEUE ((StgTSO *)(void*)&stg_END_TSO_QUEUE_closure)
245 #if defined(PAR) || defined(GRAN)
246 /* this is the NIL ptr for a blocking queue */
247 # define END_BQ_QUEUE ((StgBlockingQueueElement *)(void*)&stg_END_TSO_QUEUE_closure)
248 /* this is the NIL ptr for a blocked fetch queue (as in PendingFetches in GUM) */
249 # define END_BF_QUEUE ((StgBlockedFetch *)(void*)&stg_END_TSO_QUEUE_closure)
251 /* ToDo?: different name for end of sleeping queue ? -- HWL */