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 * Flags for the tso->flags field.
83 * The TSO_DIRTY flag indicates that this TSO's stack should be
84 * scanned during garbage collection. The link field of a TSO is
85 * always scanned, so we don't have to dirty a TSO just for linking
86 * it on a different list.
89 * - schedule(), just before running a thread,
90 * - raiseAsync(), because it modifies a thread's stack
91 * - resumeThread(), just before running the thread again
92 * and unset by the garbage collector (only).
97 * Type returned after running a thread. Values of this type
98 * include HeapOverflow, StackOverflow etc. See Constants.h for the
101 typedef unsigned int StgThreadReturnCode;
103 #if defined(mingw32_HOST_OS)
104 /* results from an async I/O request + its request ID. */
115 StgInt fd; /* StgInt instead of int, so that it's the same size as the ptrs */
116 #if defined(mingw32_HOST_OS)
117 StgAsyncIOResult *async_result;
123 * TSOs live on the heap, and therefore look just like heap objects.
124 * Large TSOs will live in their own "block group" allocated by the
125 * storage manager, and won't be copied during garbage collection.
129 * Threads may be blocked for several reasons. A blocked thread will
130 * have the reason in the why_blocked field of the TSO, and some
131 * further info (such as the closure the thread is blocked on, or the
132 * file descriptor if the thread is waiting on I/O) in the block_info
136 typedef struct StgTSO_ {
139 struct StgTSO_* link; /* Links threads onto blocking queues */
140 struct StgTSO_* global_link; /* Links all threads together */
142 StgWord16 what_next; /* Values defined in Constants.h */
143 StgWord16 why_blocked; /* Values defined in Constants.h */
145 StgTSOBlockInfo block_info;
146 struct StgTSO_* blocked_exceptions;
149 struct Task_* bound; // non-NULL for a bound thread
150 struct StgTRecHeader_ *trec; /* STM transaction record */
153 /* TICKY-specific stuff would go here. */
168 /* The thread stack... */
169 StgWord stack_size; /* stack size in *words* */
170 StgWord max_stack_size; /* maximum stack size in *words* */
173 StgWord stack[FLEXIBLE_ARRAY];
176 /* -----------------------------------------------------------------------------
179 An active thread has the following properties:
181 tso->stack < tso->sp < tso->stack+tso->stack_size
182 tso->stack_size <= tso->max_stack_size
184 RESERVED_STACK_WORDS is large enough for any heap-check or
187 The size of the TSO struct plus the stack is either
188 (a) smaller than a block, or
189 (b) a multiple of BLOCK_SIZE
191 tso->why_blocked tso->block_info location
192 ----------------------------------------------------------------------
193 NotBlocked NULL runnable_queue, or running
195 BlockedOnBlackHole the BLACKHOLE_BQ the BLACKHOLE_BQ's queue
197 BlockedOnMVar the MVAR the MVAR's queue
199 BlockedOnSTM END_TSO_QUEUE STM wait queue(s)
201 BlockedOnException the TSO TSO->blocked_exception
203 BlockedOnRead NULL blocked_queue
204 BlockedOnWrite NULL blocked_queue
205 BlockedOnDelay NULL blocked_queue
206 BlockedOnGA closure TSO blocks on BQ of that closure
207 BlockedOnGA_NoSend closure TSO blocks on BQ of that closure
209 tso->link == END_TSO_QUEUE, if the thread is currently running.
211 A zombie thread has the following properties:
213 tso->what_next == ThreadComplete or ThreadKilled
214 tso->link == (could be on some queue somewhere)
215 tso->su == tso->stack + tso->stack_size
216 tso->sp == tso->stack + tso->stack_size - 1 (i.e. top stack word)
217 tso->sp[0] == return value of thread, if what_next == ThreadComplete,
218 exception , if what_next == ThreadKilled
220 (tso->sp is left pointing at the top word on the stack so that
221 the return value or exception will be retained by a GC).
223 tso->blocked_exceptions is either:
225 NULL if async exceptions are unblocked.
227 END_TSO_QUEUE if async exceptions are blocked, but no threads
228 are currently waiting to deliver.
230 (StgTSO *)tso if threads are currently awaiting delivery of
231 exceptions to this thread.
233 The 2 cases BlockedOnGA and BlockedOnGA_NoSend are needed in a GUM
234 setup only. They mark a TSO that has entered a FETCH_ME or
235 FETCH_ME_BQ closure, respectively; only the first TSO hitting the
236 closure will send a Fetch message.
237 Currently we have no separate code for blocking on an RBH; we use the
238 BlockedOnBlackHole case for that. -- HWL
240 ---------------------------------------------------------------------------- */
242 /* Workaround for a bug/quirk in gcc on certain architectures.
243 * symptom is that (&tso->stack - &tso->header) /= sizeof(StgTSO)
244 * in other words, gcc pads the structure at the end.
247 extern StgTSO dummy_tso;
249 #define TSO_STRUCT_SIZE \
250 ((char *)&dummy_tso.stack - (char *)&dummy_tso.header)
252 #define TSO_STRUCT_SIZEW (TSO_STRUCT_SIZE / sizeof(W_))
255 /* this is the NIL ptr for a TSO queue (e.g. runnable queue) */
257 #define END_TSO_QUEUE (stg_END_TSO_QUEUE_closure)
259 #define END_TSO_QUEUE ((StgTSO *)(void*)&stg_END_TSO_QUEUE_closure)
262 #if defined(PAR) || defined(GRAN)
263 /* this is the NIL ptr for a blocking queue */
264 # define END_BQ_QUEUE ((StgBlockingQueueElement *)(void*)&stg_END_TSO_QUEUE_closure)
265 /* this is the NIL ptr for a blocked fetch queue (as in PendingFetches in GUM) */
266 # define END_BF_QUEUE ((StgBlockedFetch *)(void*)&stg_END_TSO_QUEUE_closure)
268 /* ToDo?: different name for end of sleeping queue ? -- HWL */