FIX #2164: check for ThreadRelocated in isAlive()
[ghc.git] / rts / Schedule.h
1 /* -----------------------------------------------------------------------------
2 *
3 * (c) The GHC Team 1998-2005
4 *
5 * Prototypes for functions in Schedule.c
6 * (RTS internal scheduler interface)
7 *
8 * -------------------------------------------------------------------------*/
9
10 #ifndef SCHEDULE_H
11 #define SCHEDULE_H
12
13 #include "OSThreads.h"
14 #include "Capability.h"
15
16 /* initScheduler(), exitScheduler()
17 * Called from STG : no
18 * Locks assumed : none
19 */
20 void initScheduler (void);
21 void exitScheduler (rtsBool wait_foreign);
22 void freeScheduler (void);
23
24 // Place a new thread on the run queue of the current Capability
25 void scheduleThread (Capability *cap, StgTSO *tso);
26
27 // Place a new thread on the run queue of a specified Capability
28 // (cap is the currently owned Capability, cpu is the number of
29 // the desired Capability).
30 void scheduleThreadOn(Capability *cap, StgWord cpu, StgTSO *tso);
31
32 /* awakenBlockedQueue()
33 *
34 * Takes a pointer to the beginning of a blocked TSO queue, and
35 * wakes up the entire queue.
36 * Called from STG : yes
37 * Locks assumed : none
38 */
39 #if defined(GRAN)
40 void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
41 #elif defined(PAR)
42 void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
43 #else
44 void awakenBlockedQueue (Capability *cap, StgTSO *tso);
45 #endif
46
47 /* wakeUpRts()
48 *
49 * Causes an OS thread to wake up and run the scheduler, if necessary.
50 */
51 void wakeUpRts(void);
52
53 /* unblockOne()
54 *
55 * Put the specified thread on the run queue of the given Capability.
56 * Called from STG : yes
57 * Locks assumed : we own the Capability.
58 */
59 StgTSO * unblockOne (Capability *cap, StgTSO *tso);
60
61 /* raiseExceptionHelper */
62 StgWord raiseExceptionHelper (StgRegTable *reg, StgTSO *tso, StgClosure *exception);
63
64 /* findRetryFrameHelper */
65 StgWord findRetryFrameHelper (StgTSO *tso);
66
67 /* workerStart()
68 *
69 * Entry point for a new worker task.
70 * Called from STG : NO
71 * Locks assumed : none
72 */
73 void workerStart(Task *task);
74
75 #if defined(GRAN)
76 void awaken_blocked_queue(StgBlockingQueueElement *q, StgClosure *node);
77 void unlink_from_bq(StgTSO* tso, StgClosure* node);
78 void initThread(StgTSO *tso, nat stack_size, StgInt pri);
79 #elif defined(PAR)
80 nat run_queue_len(void);
81 void awaken_blocked_queue(StgBlockingQueueElement *q, StgClosure *node);
82 void initThread(StgTSO *tso, nat stack_size);
83 #else
84 char *info_type(StgClosure *closure); // dummy
85 char *info_type_by_ip(StgInfoTable *ip); // dummy
86 void awaken_blocked_queue(StgTSO *q);
87 void initThread(StgTSO *tso, nat stack_size);
88 #endif
89
90 /* Context switch flag.
91 * Locks required : none (conflicts are harmless)
92 */
93 extern int RTS_VAR(context_switch);
94
95 /* The state of the scheduler. This is used to control the sequence
96 * of events during shutdown, and when the runtime is interrupted
97 * using ^C.
98 */
99 #define SCHED_RUNNING 0 /* running as normal */
100 #define SCHED_INTERRUPTING 1 /* ^C detected, before threads are deleted */
101 #define SCHED_SHUTTING_DOWN 2 /* final shutdown */
102
103 extern rtsBool RTS_VAR(sched_state);
104
105 /*
106 * flag that tracks whether we have done any execution in this time slice.
107 */
108 #define ACTIVITY_YES 0 /* there has been activity in the current slice */
109 #define ACTIVITY_MAYBE_NO 1 /* no activity in the current slice */
110 #define ACTIVITY_INACTIVE 2 /* a complete slice has passed with no activity */
111 #define ACTIVITY_DONE_GC 3 /* like 2, but we've done a GC too */
112
113 /* Recent activity flag.
114 * Locks required : Transition from MAYBE_NO to INACTIVE
115 * happens in the timer signal, so it is atomic. Trnasition from
116 * INACTIVE to DONE_GC happens under sched_mutex. No lock required
117 * to set it to ACTIVITY_YES.
118 */
119 extern nat recent_activity;
120
121 /* Thread queues.
122 * Locks required : sched_mutex
123 *
124 * In GranSim we have one run/blocked_queue per PE.
125 */
126 #if defined(GRAN)
127 // run_queue_hds defined in GranSim.h
128 #else
129 extern StgTSO *RTS_VAR(blackhole_queue);
130 #if !defined(THREADED_RTS)
131 extern StgTSO *RTS_VAR(blocked_queue_hd), *RTS_VAR(blocked_queue_tl);
132 extern StgTSO *RTS_VAR(sleeping_queue);
133 #endif
134 #endif
135
136 /* Set to rtsTrue if there are threads on the blackhole_queue, and
137 * it is possible that one or more of them may be available to run.
138 * This flag is set to rtsFalse after we've checked the queue, and
139 * set to rtsTrue just before we run some Haskell code. It is used
140 * to decide whether we should yield the Capability or not.
141 * Locks required : none (see scheduleCheckBlackHoles()).
142 */
143 extern rtsBool blackholes_need_checking;
144
145 #if defined(THREADED_RTS)
146 extern Mutex RTS_VAR(sched_mutex);
147 #endif
148
149 SchedulerStatus rts_mainLazyIO(HaskellObj p, /*out*/HaskellObj *ret);
150
151 /* Called by shutdown_handler(). */
152 void interruptStgRts (void);
153
154 nat run_queue_len (void);
155
156 void resurrectThreads (StgTSO *);
157 void performPendingThrowTos (StgTSO *);
158
159 void printAllThreads(void);
160
161 /* debugging only
162 */
163 #ifdef DEBUG
164 void print_bq (StgClosure *node);
165 #endif
166 #if defined(PAR)
167 void print_bqe (StgBlockingQueueElement *bqe);
168 #endif
169
170 /* -----------------------------------------------------------------------------
171 * Some convenient macros/inline functions...
172 */
173
174 #if !IN_STG_CODE
175
176 /* END_TSO_QUEUE and friends now defined in includes/StgMiscClosures.h */
177
178 /* Add a thread to the end of the run queue.
179 * NOTE: tso->link should be END_TSO_QUEUE before calling this macro.
180 * ASSUMES: cap->running_task is the current task.
181 */
182 INLINE_HEADER void
183 appendToRunQueue (Capability *cap, StgTSO *tso)
184 {
185 ASSERT(tso->_link == END_TSO_QUEUE);
186 if (cap->run_queue_hd == END_TSO_QUEUE) {
187 cap->run_queue_hd = tso;
188 } else {
189 setTSOLink(cap, cap->run_queue_tl, tso);
190 }
191 cap->run_queue_tl = tso;
192 }
193
194 /* Push a thread on the beginning of the run queue. Used for
195 * newly awakened threads, so they get run as soon as possible.
196 * ASSUMES: cap->running_task is the current task.
197 */
198 INLINE_HEADER void
199 pushOnRunQueue (Capability *cap, StgTSO *tso)
200 {
201 setTSOLink(cap, tso, cap->run_queue_hd);
202 cap->run_queue_hd = tso;
203 if (cap->run_queue_tl == END_TSO_QUEUE) {
204 cap->run_queue_tl = tso;
205 }
206 }
207
208 /* Pop the first thread off the runnable queue.
209 */
210 INLINE_HEADER StgTSO *
211 popRunQueue (Capability *cap)
212 {
213 StgTSO *t = cap->run_queue_hd;
214 ASSERT(t != END_TSO_QUEUE);
215 cap->run_queue_hd = t->_link;
216 t->_link = END_TSO_QUEUE; // no write barrier req'd
217 if (cap->run_queue_hd == END_TSO_QUEUE) {
218 cap->run_queue_tl = END_TSO_QUEUE;
219 }
220 return t;
221 }
222
223 /* Add a thread to the end of the blocked queue.
224 */
225 #if !defined(THREADED_RTS)
226 INLINE_HEADER void
227 appendToBlockedQueue(StgTSO *tso)
228 {
229 ASSERT(tso->_link == END_TSO_QUEUE);
230 if (blocked_queue_hd == END_TSO_QUEUE) {
231 blocked_queue_hd = tso;
232 } else {
233 setTSOLink(&MainCapability, blocked_queue_tl, tso);
234 }
235 blocked_queue_tl = tso;
236 }
237 #endif
238
239 #if defined(THREADED_RTS)
240 INLINE_HEADER void
241 appendToWakeupQueue (Capability *cap, StgTSO *tso)
242 {
243 ASSERT(tso->_link == END_TSO_QUEUE);
244 if (cap->wakeup_queue_hd == END_TSO_QUEUE) {
245 cap->wakeup_queue_hd = tso;
246 } else {
247 setTSOLink(cap, cap->wakeup_queue_tl, tso);
248 }
249 cap->wakeup_queue_tl = tso;
250 }
251 #endif
252
253 /* Check whether various thread queues are empty
254 */
255 INLINE_HEADER rtsBool
256 emptyQueue (StgTSO *q)
257 {
258 return (q == END_TSO_QUEUE);
259 }
260
261 INLINE_HEADER rtsBool
262 emptyRunQueue(Capability *cap)
263 {
264 return emptyQueue(cap->run_queue_hd);
265 }
266
267 #if defined(THREADED_RTS)
268 INLINE_HEADER rtsBool
269 emptyWakeupQueue(Capability *cap)
270 {
271 return emptyQueue(cap->wakeup_queue_hd);
272 }
273 #endif
274
275 #if !defined(THREADED_RTS)
276 #define EMPTY_BLOCKED_QUEUE() (emptyQueue(blocked_queue_hd))
277 #define EMPTY_SLEEPING_QUEUE() (emptyQueue(sleeping_queue))
278 #endif
279
280 INLINE_HEADER rtsBool
281 emptyThreadQueues(Capability *cap)
282 {
283 return emptyRunQueue(cap)
284 #if !defined(THREADED_RTS)
285 && EMPTY_BLOCKED_QUEUE() && EMPTY_SLEEPING_QUEUE()
286 #endif
287 ;
288 }
289
290 #endif /* !IN_STG_CODE */
291
292 #endif /* SCHEDULE_H */
293