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).
96 #define tsoDirty(tso) ((tso)->flags & TSO_DIRTY)
99 * Type returned after running a thread. Values of this type
100 * include HeapOverflow, StackOverflow etc. See Constants.h for the
103 typedef unsigned int StgThreadReturnCode;
105 #if defined(mingw32_HOST_OS)
106 /* results from an async I/O request + its request ID. */
117 StgInt fd; /* StgInt instead of int, so that it's the same size as the ptrs */
118 #if defined(mingw32_HOST_OS)
119 StgAsyncIOResult *async_result;
125 * TSOs live on the heap, and therefore look just like heap objects.
126 * Large TSOs will live in their own "block group" allocated by the
127 * storage manager, and won't be copied during garbage collection.
131 * Threads may be blocked for several reasons. A blocked thread will
132 * have the reason in the why_blocked field of the TSO, and some
133 * further info (such as the closure the thread is blocked on, or the
134 * file descriptor if the thread is waiting on I/O) in the block_info
138 typedef struct StgTSO_ {
141 struct StgTSO_* link; /* Links threads onto blocking queues */
142 struct StgTSO_* global_link; /* Links all threads together */
144 StgWord16 what_next; /* Values defined in Constants.h */
145 StgWord16 why_blocked; /* Values defined in Constants.h */
147 StgTSOBlockInfo block_info;
148 struct StgTSO_* blocked_exceptions;
152 struct Capability_* cap;
153 struct StgTRecHeader_ * trec; /* STM transaction record */
156 /* TICKY-specific stuff would go here. */
171 /* The thread stack... */
172 StgWord32 stack_size; /* stack size in *words* */
173 StgWord32 max_stack_size; /* maximum stack size in *words* */
176 StgWord stack[FLEXIBLE_ARRAY];
179 /* -----------------------------------------------------------------------------
182 An active thread has the following properties:
184 tso->stack < tso->sp < tso->stack+tso->stack_size
185 tso->stack_size <= tso->max_stack_size
187 RESERVED_STACK_WORDS is large enough for any heap-check or
190 The size of the TSO struct plus the stack is either
191 (a) smaller than a block, or
192 (b) a multiple of BLOCK_SIZE
194 tso->why_blocked tso->block_info location
195 ----------------------------------------------------------------------
196 NotBlocked NULL runnable_queue, or running
198 BlockedOnBlackHole the BLACKHOLE_BQ the BLACKHOLE_BQ's queue
200 BlockedOnMVar the MVAR the MVAR's queue
202 BlockedOnSTM END_TSO_QUEUE STM wait queue(s)
204 BlockedOnException the TSO TSO->blocked_exception
206 BlockedOnRead NULL blocked_queue
207 BlockedOnWrite NULL blocked_queue
208 BlockedOnDelay NULL blocked_queue
209 BlockedOnGA closure TSO blocks on BQ of that closure
210 BlockedOnGA_NoSend closure TSO blocks on BQ of that closure
212 tso->link == END_TSO_QUEUE, if the thread is currently running.
214 A zombie thread has the following properties:
216 tso->what_next == ThreadComplete or ThreadKilled
217 tso->link == (could be on some queue somewhere)
218 tso->su == tso->stack + tso->stack_size
219 tso->sp == tso->stack + tso->stack_size - 1 (i.e. top stack word)
220 tso->sp[0] == return value of thread, if what_next == ThreadComplete,
221 exception , if what_next == ThreadKilled
223 (tso->sp is left pointing at the top word on the stack so that
224 the return value or exception will be retained by a GC).
226 tso->blocked_exceptions is either:
228 NULL if async exceptions are unblocked.
230 END_TSO_QUEUE if async exceptions are blocked, but no threads
231 are currently waiting to deliver.
233 (StgTSO *)tso if threads are currently awaiting delivery of
234 exceptions to this thread.
236 The 2 cases BlockedOnGA and BlockedOnGA_NoSend are needed in a GUM
237 setup only. They mark a TSO that has entered a FETCH_ME or
238 FETCH_ME_BQ closure, respectively; only the first TSO hitting the
239 closure will send a Fetch message.
240 Currently we have no separate code for blocking on an RBH; we use the
241 BlockedOnBlackHole case for that. -- HWL
243 ---------------------------------------------------------------------------- */
245 /* Workaround for a bug/quirk in gcc on certain architectures.
246 * symptom is that (&tso->stack - &tso->header) /= sizeof(StgTSO)
247 * in other words, gcc pads the structure at the end.
250 extern StgTSO dummy_tso;
252 #define TSO_STRUCT_SIZE \
253 ((char *)&dummy_tso.stack - (char *)&dummy_tso.header)
255 #define TSO_STRUCT_SIZEW (TSO_STRUCT_SIZE / sizeof(W_))
258 /* this is the NIL ptr for a TSO queue (e.g. runnable queue) */
260 #define END_TSO_QUEUE (stg_END_TSO_QUEUE_closure)
262 #define END_TSO_QUEUE ((StgTSO *)(void*)&stg_END_TSO_QUEUE_closure)
265 #if defined(PAR) || defined(GRAN)
266 /* this is the NIL ptr for a blocking queue */
267 # define END_BQ_QUEUE ((StgBlockingQueueElement *)(void*)&stg_END_TSO_QUEUE_closure)
268 /* this is the NIL ptr for a blocked fetch queue (as in PendingFetches in GUM) */
269 # define END_BF_QUEUE ((StgBlockedFetch *)(void*)&stg_END_TSO_QUEUE_closure)
271 /* ToDo?: different name for end of sleeping queue ? -- HWL */