1 /* -----------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-2009
5 * The definitions for Thread State Objects.
7 * ---------------------------------------------------------------------------*/
9 #ifndef RTS_STORAGE_TSO_H
10 #define RTS_STORAGE_TSO_H
13 * PROFILING info in a TSO
16 CostCentreStack *CCCS; /* thread's current CCS */
20 * There is no TICKY info in a TSO at this time.
24 * Thread IDs are 32 bits.
26 typedef StgWord32 StgThreadID;
28 #define tsoLocked(tso) ((tso)->flags & TSO_LOCKED)
31 * Type returned after running a thread. Values of this type
32 * include HeapOverflow, StackOverflow etc. See Constants.h for the
35 typedef unsigned int StgThreadReturnCode;
37 #if defined(mingw32_HOST_OS)
38 /* results from an async I/O request + its request ID. */
46 /* Reason for thread being blocked. See comment above struct StgTso_. */
49 struct MessageBlackHole_ *bh;
50 struct MessageThrowTo_ *throwto;
51 struct MessageWakeup_ *wakeup;
52 StgInt fd; /* StgInt instead of int, so that it's the same size as the ptrs */
53 #if defined(mingw32_HOST_OS)
54 StgAsyncIOResult *async_result;
61 * TSOs live on the heap, and therefore look just like heap objects.
62 * Large TSOs will live in their own "block group" allocated by the
63 * storage manager, and won't be copied during garbage collection.
67 * Threads may be blocked for several reasons. A blocked thread will
68 * have the reason in the why_blocked field of the TSO, and some
69 * further info (such as the closure the thread is blocked on, or the
70 * file descriptor if the thread is waiting on I/O) in the block_info
74 typedef struct StgTSO_ {
77 /* The link field, for linking threads together in lists (e.g. the
78 run queue on a Capability.
80 struct StgTSO_* _link;
82 Currently used for linking TSOs on:
83 * cap->run_queue_{hd,tl}
85 * (non-THREADED_RTS); the blocked_queue
86 * and pointing to the relocated version of a ThreadRelocated
88 NOTE!!! do not modify _link directly, it is subject to
89 a write barrier for generational GC. Instead use the
90 setTSOLink() function. Exceptions to this rule are:
92 * setting the link field to END_TSO_QUEUE
93 * setting the link field of the currently running TSO, as it
94 will already be dirty.
97 struct StgTSO_* global_link; // Links threads on the
98 // generation->threads lists
100 StgWord dirty; /* non-zero => dirty */
102 * The tso->dirty flag indicates that this TSO's stack should be
103 * scanned during garbage collection. It also indicates that this
104 * TSO is on the mutable list.
106 * NB. The dirty flag gets a word to itself, so that it can be set
107 * safely by multiple threads simultaneously (the flags field is
108 * not safe for this purpose; see #3429). It is harmless for the
109 * TSO to be on the mutable list multiple times.
111 * tso->dirty is set by dirty_TSO(), and unset by the garbage
114 * The link field has a separate dirty bit of its own, namely the
115 * bit TSO_LINK_DIRTY in the tso->flags field, set by
119 StgWord16 what_next; // Values defined in Constants.h
120 StgWord16 why_blocked; // Values defined in Constants.h
121 StgWord32 flags; // Values defined in Constants.h
122 StgTSOBlockInfo block_info;
125 struct InCall_* bound;
126 struct Capability_* cap;
127 struct StgTRecHeader_ * trec; /* STM transaction record */
130 A list of threads blocked on this TSO waiting to throw
131 exceptions. In order to access this field, the TSO must be
132 locked using lockClosure/unlockClosure (see SMP.h).
134 struct MessageThrowTo_ * blocked_exceptions;
137 A list of StgBlockingQueue objects, representing threads blocked
138 on thunks that are under evaluation by this thread.
140 struct StgBlockingQueue_ *bq;
143 /* TICKY-specific stuff would go here. */
148 #ifdef mingw32_HOST_OS
149 StgWord32 saved_winerror;
152 /* The thread stack... */
153 StgWord32 stack_size; /* stack size in *words* */
154 StgWord32 max_stack_size; /* maximum stack size in *words* */
157 StgWord stack[FLEXIBLE_ARRAY];
160 /* -----------------------------------------------------------------------------
162 -------------------------------------------------------------------------- */
164 void dirty_TSO (Capability *cap, StgTSO *tso);
165 void setTSOLink (Capability *cap, StgTSO *tso, StgTSO *target);
167 // Apply to a TSO before looking at it if you are not sure whether it
168 // might be ThreadRelocated or not (basically, that's most of the time
169 // unless the TSO is the current TSO).
171 INLINE_HEADER StgTSO * deRefTSO(StgTSO *tso)
173 while (tso->what_next == ThreadRelocated) {
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 END_TSO_QUEUE runnable_queue, or running
198 BlockedOnBlackHole the BLACKHOLE blackhole_queue
200 BlockedOnMVar the MVAR the MVAR's queue
202 BlockedOnSTM END_TSO_QUEUE STM wait queue(s)
204 BlockedOnMsgThrowTo MessageThrowTo * 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->sp == tso->stack + tso->stack_size - 1 (i.e. top stack word)
219 tso->sp[0] == return value of thread, if what_next == ThreadComplete,
220 exception , if what_next == ThreadKilled
222 (tso->sp is left pointing at the top word on the stack so that
223 the return value or exception will be retained by a GC).
225 The 2 cases BlockedOnGA and BlockedOnGA_NoSend are needed in a GUM
226 setup only. They mark a TSO that has entered a FETCH_ME or
227 FETCH_ME_BQ closure, respectively; only the first TSO hitting the
228 closure will send a Fetch message.
229 Currently we have no separate code for blocking on an RBH; we use the
230 BlockedOnBlackHole case for that. -- HWL
232 ---------------------------------------------------------------------------- */
234 /* Workaround for a bug/quirk in gcc on certain architectures.
235 * symptom is that (&tso->stack - &tso->header) /= sizeof(StgTSO)
236 * in other words, gcc pads the structure at the end.
239 extern StgTSO dummy_tso;
241 #define TSO_STRUCT_SIZE \
242 ((char *)&dummy_tso.stack - (char *)&dummy_tso.header)
244 #define TSO_STRUCT_SIZEW (TSO_STRUCT_SIZE / sizeof(W_))
246 /* this is the NIL ptr for a TSO queue (e.g. runnable queue) */
247 #define END_TSO_QUEUE ((StgTSO *)(void*)&stg_END_TSO_QUEUE_closure)
249 #endif /* RTS_STORAGE_TSO_H */