#if defined(PAR) || defined(GRAN)
static void scheduleGranParReport(void);
#endif
-static void schedulePostRunThread(void);
+static void schedulePostRunThread(StgTSO *t);
static rtsBool scheduleHandleHeapOverflow( Capability *cap, StgTSO *t );
static void scheduleHandleStackOverflow( Capability *cap, Task *task,
StgTSO *t);
CCCS = CCS_SYSTEM;
#endif
- schedulePostRunThread();
+ schedulePostRunThread(t);
t = threadStackUnderflow(task,t);
* ------------------------------------------------------------------------- */
static void
-schedulePostRunThread(void)
+schedulePostRunThread (StgTSO *t)
{
+ // We have to be able to catch transactions that are in an
+ // infinite loop as a result of seeing an inconsistent view of
+ // memory, e.g.
+ //
+ // atomically $ do
+ // [a,b] <- mapM readTVar [ta,tb]
+ // when (a == b) loop
+ //
+ // and a is never equal to b given a consistent view of memory.
+ //
+ if (t -> trec != NO_TREC && t -> why_blocked == NotBlocked) {
+ if (!stmValidateNestOfTransactions (t -> trec)) {
+ debugTrace(DEBUG_sched | DEBUG_stm,
+ "trec %p found wasting its time", t);
+
+ // strip the stack back to the
+ // ATOMICALLY_FRAME, aborting the (nested)
+ // transaction, and saving the stack of any
+ // partially-evaluated thunks on the heap.
+ throwToSingleThreaded_(&capabilities[0], t,
+ NULL, rtsTrue, NULL);
+
+#ifdef REG_R1
+ ASSERT(get_itbl((StgClosure *)t->sp)->type == ATOMICALLY_FRAME);
+#endif
+ }
+ }
+
#if defined(PAR)
/* HACK 675: if the last thread didn't yield, make sure to print a
SCHEDULE event to the log file when StgRunning the next thread, even
waiting_for_gc = rtsFalse;
#endif
- /* Kick any transactions which are invalid back to their
- * atomically frames. When next scheduled they will try to
- * commit, this commit will fail and they will retry.
- */
- {
- StgTSO *next;
- nat s;
-
- for (s = 0; s < total_steps; s++) {
- for (t = all_steps[s].threads; t != END_TSO_QUEUE; t = next) {
- if (t->what_next == ThreadRelocated) {
- next = t->_link;
- } else {
- next = t->global_link;
-
- // This is a good place to check for blocked
- // exceptions. It might be the case that a thread is
- // blocked on delivering an exception to a thread that
- // is also blocked - we try to ensure that this
- // doesn't happen in throwTo(), but it's too hard (or
- // impossible) to close all the race holes, so we
- // accept that some might get through and deal with
- // them here. A GC will always happen at some point,
- // even if the system is otherwise deadlocked.
- maybePerformBlockedException (&capabilities[0], t);
-
- if (t -> trec != NO_TREC && t -> why_blocked == NotBlocked) {
- if (!stmValidateNestOfTransactions (t -> trec)) {
- debugTrace(DEBUG_sched | DEBUG_stm,
- "trec %p found wasting its time", t);
-
- // strip the stack back to the
- // ATOMICALLY_FRAME, aborting the (nested)
- // transaction, and saving the stack of any
- // partially-evaluated thunks on the heap.
- throwToSingleThreaded_(&capabilities[0], t,
- NULL, rtsTrue, NULL);
-
-#ifdef REG_R1
- ASSERT(get_itbl((StgClosure *)t->sp)->type == ATOMICALLY_FRAME);
-#endif
- }
- }
- }
- }
- }
- }
-
// so this happens periodically:
if (cap) scheduleCheckBlackHoles(cap);
}
}
}
+
+/* -----------------------------------------------------------------------------
+ performPendingThrowTos is called after garbage collection, and
+ passed a list of threads that were found to have pending throwTos
+ (tso->blocked_exceptions was not empty), and were blocked.
+ Normally this doesn't happen, because we would deliver the
+ exception directly if the target thread is blocked, but there are
+ small windows where it might occur on a multiprocessor (see
+ throwTo()).
+
+ NB. we must be holding all the capabilities at this point, just
+ like resurrectThreads().
+ -------------------------------------------------------------------------- */
+
+void
+performPendingThrowTos (StgTSO *threads)
+{
+ StgTSO *tso, *next;
+ Capability *cap;
+ step *step;
+
+ for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
+ next = tso->global_link;
+
+ step = Bdescr((P_)tso)->step;
+ tso->global_link = step->threads;
+ step->threads = tso;
+
+ debugTrace(DEBUG_sched, "performing blocked throwTo to thread %lu", (unsigned long)tso->id);
+
+ cap = tso->cap;
+ maybePerformBlockedException(cap, tso);
+ }
+}
*/
StgWeak *old_weak_ptr_list; // also pending finaliser list
-/* List of all threads during GC
- */
+// List of threads found to be unreachable
StgTSO *resurrected_threads;
+// List of blocked threads found to have pending throwTos
+StgTSO *exception_threads;
+
void
initWeakForGC(void)
{
weak_ptr_list = NULL;
weak_stage = WeakPtrs;
resurrected_threads = END_TSO_QUEUE;
+ exception_threads = END_TSO_QUEUE;
}
rtsBool
next = t->global_link;
}
else {
- step *new_step;
- // alive: move this thread onto the correct
- // threads list.
+ // alive
next = t->global_link;
- new_step = Bdescr((P_)t)->step;
- t->global_link = new_step->threads;
- new_step->threads = t;
*prev = next;
+
+ // This is a good place to check for blocked
+ // exceptions. It might be the case that a thread is
+ // blocked on delivering an exception to a thread that
+ // is also blocked - we try to ensure that this
+ // doesn't happen in throwTo(), but it's too hard (or
+ // impossible) to close all the race holes, so we
+ // accept that some might get through and deal with
+ // them here. A GC will always happen at some point,
+ // even if the system is otherwise deadlocked.
+ if (t->blocked_exceptions != END_TSO_QUEUE) {
+ t->global_link = exception_threads;
+ exception_threads = t;
+ } else {
+ // move this thread onto the correct threads list.
+ step *new_step;
+ new_step = Bdescr((P_)t)->step;
+ t->global_link = new_step->threads;
+ new_step->threads = t;
+ }
}
}
}
projects / ghc-hetmet.git / commitdiff