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;
80 #define tsoDirty(tso) ((tso)->flags & TSO_DIRTY)
81 #define tsoLocked(tso) ((tso)->flags & TSO_LOCKED)
84 * Type returned after running a thread. Values of this type
85 * include HeapOverflow, StackOverflow etc. See Constants.h for the
88 typedef unsigned int StgThreadReturnCode;
90 #if defined(mingw32_HOST_OS)
91 /* results from an async I/O request + its request ID. */
102 StgInt fd; /* StgInt instead of int, so that it's the same size as the ptrs */
103 #if defined(mingw32_HOST_OS)
104 StgAsyncIOResult *async_result;
111 * TSOs live on the heap, and therefore look just like heap objects.
112 * Large TSOs will live in their own "block group" allocated by the
113 * storage manager, and won't be copied during garbage collection.
117 * Threads may be blocked for several reasons. A blocked thread will
118 * have the reason in the why_blocked field of the TSO, and some
119 * further info (such as the closure the thread is blocked on, or the
120 * file descriptor if the thread is waiting on I/O) in the block_info
124 typedef struct StgTSO_ {
127 /* The link field, for linking threads together in lists (e.g. the
128 run queue on a Capability.
130 struct StgTSO_* _link;
132 NOTE!!! do not modify _link directly, it is subject to
133 a write barrier for generational GC. Instead use the
134 setTSOLink() function. Exceptions to this rule are:
136 * setting the link field to END_TSO_QUEUE
137 * putting a TSO on the blackhole_queue
138 * setting the link field of the currently running TSO, as it
139 will already be dirty.
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;
151 struct Capability_* cap;
152 struct StgTRecHeader_ * trec; /* STM transaction record */
155 A list of threads blocked on this TSO waiting to throw
156 exceptions. In order to access this field, the TSO must be
157 locked using lockClosure/unlockClosure (see SMP.h).
159 struct StgTSO_ * blocked_exceptions;
162 /* TICKY-specific stuff would go here. */
176 #ifdef mingw32_HOST_OS
177 StgWord32 saved_winerror;
180 /* The thread stack... */
181 StgWord32 stack_size; /* stack size in *words* */
182 StgWord32 max_stack_size; /* maximum stack size in *words* */
185 StgWord stack[FLEXIBLE_ARRAY];
188 /* -----------------------------------------------------------------------------
190 -------------------------------------------------------------------------- */
192 extern void dirty_TSO (Capability *cap, StgTSO *tso);
193 extern void setTSOLink (Capability *cap, StgTSO *tso, StgTSO *target);
195 /* -----------------------------------------------------------------------------
198 An active thread has the following properties:
200 tso->stack < tso->sp < tso->stack+tso->stack_size
201 tso->stack_size <= tso->max_stack_size
203 RESERVED_STACK_WORDS is large enough for any heap-check or
206 The size of the TSO struct plus the stack is either
207 (a) smaller than a block, or
208 (b) a multiple of BLOCK_SIZE
210 tso->why_blocked tso->block_info location
211 ----------------------------------------------------------------------
212 NotBlocked NULL runnable_queue, or running
214 BlockedOnBlackHole the BLACKHOLE_BQ the BLACKHOLE_BQ's queue
216 BlockedOnMVar the MVAR the MVAR's queue
218 BlockedOnSTM END_TSO_QUEUE STM wait queue(s)
220 BlockedOnException the TSO TSO->blocked_exception
222 BlockedOnRead NULL blocked_queue
223 BlockedOnWrite NULL blocked_queue
224 BlockedOnDelay NULL blocked_queue
225 BlockedOnGA closure TSO blocks on BQ of that closure
226 BlockedOnGA_NoSend closure TSO blocks on BQ of that closure
228 tso->link == END_TSO_QUEUE, if the thread is currently running.
230 A zombie thread has the following properties:
232 tso->what_next == ThreadComplete or ThreadKilled
233 tso->link == (could be on some queue somewhere)
234 tso->su == tso->stack + tso->stack_size
235 tso->sp == tso->stack + tso->stack_size - 1 (i.e. top stack word)
236 tso->sp[0] == return value of thread, if what_next == ThreadComplete,
237 exception , if what_next == ThreadKilled
239 (tso->sp is left pointing at the top word on the stack so that
240 the return value or exception will be retained by a GC).
242 The 2 cases BlockedOnGA and BlockedOnGA_NoSend are needed in a GUM
243 setup only. They mark a TSO that has entered a FETCH_ME or
244 FETCH_ME_BQ closure, respectively; only the first TSO hitting the
245 closure will send a Fetch message.
246 Currently we have no separate code for blocking on an RBH; we use the
247 BlockedOnBlackHole case for that. -- HWL
249 ---------------------------------------------------------------------------- */
251 /* Workaround for a bug/quirk in gcc on certain architectures.
252 * symptom is that (&tso->stack - &tso->header) /= sizeof(StgTSO)
253 * in other words, gcc pads the structure at the end.
256 extern StgTSO dummy_tso;
258 #define TSO_STRUCT_SIZE \
259 ((char *)&dummy_tso.stack - (char *)&dummy_tso.header)
261 #define TSO_STRUCT_SIZEW (TSO_STRUCT_SIZE / sizeof(W_))
264 /* this is the NIL ptr for a TSO queue (e.g. runnable queue) */
265 #define END_TSO_QUEUE ((StgTSO *)(void*)&stg_END_TSO_QUEUE_closure)
267 #if defined(PAR) || defined(GRAN)
268 /* this is the NIL ptr for a blocking queue */
269 # define END_BQ_QUEUE ((StgBlockingQueueElement *)(void*)&stg_END_TSO_QUEUE_closure)
270 /* this is the NIL ptr for a blocked fetch queue (as in PendingFetches in GUM) */
271 # define END_BF_QUEUE ((StgBlockedFetch *)(void*)&stg_END_TSO_QUEUE_closure)
273 /* ToDo?: different name for end of sleeping queue ? -- HWL */