*/
rtsBool blackholes_need_checking = rtsFalse;
-/* Linked list of all threads.
- * Used for detecting garbage collected threads.
- * LOCK: sched_mutex+capability, or all capabilities
- */
-StgTSO *all_threads = NULL;
-
/* flag set by signal handler to precipitate a context switch
* LOCK: none (just an advisory flag)
*/
static rtsBool checkBlackHoles(Capability *cap);
static StgTSO *threadStackOverflow(Capability *cap, StgTSO *tso);
+static StgTSO *threadStackUnderflow(Task *task, StgTSO *tso);
static void deleteThread (Capability *cap, StgTSO *tso);
static void deleteAllThreads (Capability *cap);
cap->in_haskell = rtsTrue;
- dirtyTSO(t);
+ dirty_TSO(cap,t);
#if defined(THREADED_RTS)
if (recent_activity == ACTIVITY_DONE_GC) {
// ACTIVITY_DONE_GC means we turned off the timer signal to
// conserve power (see #1623). Re-enable it here.
nat prev;
- prev = xchg(&recent_activity, ACTIVITY_YES);
+ prev = xchg((P_)&recent_activity, ACTIVITY_YES);
if (prev == ACTIVITY_DONE_GC) {
startTimer();
}
schedulePostRunThread();
+ t = threadStackUnderflow(task,t);
+
ready_to_gc = rtsFalse;
switch (ret) {
cap = scheduleDoGC(cap,task,rtsFalse);
}
} /* end of while() */
-
- debugTrace(PAR_DEBUG_verbose,
- "== Leaving schedule() after having received Finish");
}
/* ----------------------------------------------------------------------------
// Check whether we have more threads on our run queue, or sparks
// in our pool, that we could hand to another Capability.
- if ((emptyRunQueue(cap) || cap->run_queue_hd->link == END_TSO_QUEUE)
+ if ((emptyRunQueue(cap) || cap->run_queue_hd->_link == END_TSO_QUEUE)
&& sparkPoolSizeCap(cap) < 2) {
return;
}
if (cap->run_queue_hd != END_TSO_QUEUE) {
prev = cap->run_queue_hd;
- t = prev->link;
- prev->link = END_TSO_QUEUE;
+ t = prev->_link;
+ prev->_link = END_TSO_QUEUE;
for (; t != END_TSO_QUEUE; t = next) {
- next = t->link;
- t->link = END_TSO_QUEUE;
+ next = t->_link;
+ t->_link = END_TSO_QUEUE;
if (t->what_next == ThreadRelocated
|| t->bound == task // don't move my bound thread
|| tsoLocked(t)) { // don't move a locked thread
- prev->link = t;
+ setTSOLink(cap, prev, t);
prev = t;
} else if (i == n_free_caps) {
pushed_to_all = rtsTrue;
i = 0;
// keep one for us
- prev->link = t;
+ setTSOLink(cap, prev, t);
prev = t;
} else {
debugTrace(DEBUG_sched, "pushing thread %lu to capability %d", (unsigned long)t->id, free_caps[i]->no);
cap->run_queue_hd = cap->wakeup_queue_hd;
cap->run_queue_tl = cap->wakeup_queue_tl;
} else {
- cap->run_queue_tl->link = cap->wakeup_queue_hd;
+ setTSOLink(cap, cap->run_queue_tl, cap->wakeup_queue_hd);
cap->run_queue_tl = cap->wakeup_queue_tl;
}
cap->wakeup_queue_hd = cap->wakeup_queue_tl = END_TSO_QUEUE;
}
#endif
- pushOnRunQueue(cap,t);
+ if (context_switch) {
+ // Sometimes we miss a context switch, e.g. when calling
+ // primitives in a tight loop, MAYBE_GC() doesn't check the
+ // context switch flag, and we end up waiting for a GC.
+ // See #1984, and concurrent/should_run/1984
+ context_switch = 0;
+ addToRunQueue(cap,t);
+ } else {
+ pushOnRunQueue(cap,t);
+ }
return rtsTrue;
/* actual GC is done at the end of the while loop in schedule() */
}
IF_DEBUG(sanity,
//debugBelch("&& Doing sanity check on yielding TSO %ld.", t->id);
checkTSO(t));
- ASSERT(t->link == END_TSO_QUEUE);
+ ASSERT(t->_link == END_TSO_QUEUE);
// Shortcut if we're just switching evaluators: don't bother
// doing stack squeezing (which can be expensive), just run the
// point where we can deal with this. Leaving it on the run
// queue also ensures that the garbage collector knows about
// this thread and its return value (it gets dropped from the
- // all_threads list so there's no other way to find it).
+ // step->threads list so there's no other way to find it).
appendToRunQueue(cap,t);
return rtsFalse;
#else
*/
{
StgTSO *next;
+ nat s;
- for (t = all_threads; t != END_TSO_QUEUE; t = next) {
+ 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;
+ next = t->_link;
} else {
next = t->global_link;
}
}
}
+ }
}
}
pid_t pid;
StgTSO* t,*next;
Capability *cap;
+ nat s;
#if defined(THREADED_RTS)
if (RtsFlags.ParFlags.nNodes > 1) {
// all Tasks, because they correspond to OS threads that are
// now gone.
- for (t = all_threads; t != END_TSO_QUEUE; t = next) {
+ 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;
+ next = t->_link;
} else {
next = t->global_link;
// don't allow threads to catch the ThreadKilled
// threads may be evaluating thunks that we need later.
deleteThread_(cap,t);
}
+ }
}
// Empty the run queue. It seems tempting to let all the
// don't exist now:
cap->suspended_ccalling_tasks = NULL;
- // Empty the all_threads list. Otherwise, the garbage
+ // Empty the threads lists. Otherwise, the garbage
// collector may attempt to resurrect some of these threads.
- all_threads = END_TSO_QUEUE;
+ for (s = 0; s < total_steps; s++) {
+ all_steps[s].threads = END_TSO_QUEUE;
+ }
// Wipe the task list, except the current Task.
ACQUIRE_LOCK(&sched_mutex);
// NOTE: only safe to call if we own all capabilities.
StgTSO* t, *next;
+ nat s;
+
debugTrace(DEBUG_sched,"deleting all threads");
- for (t = all_threads; t != END_TSO_QUEUE; t = next) {
+ 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;
+ next = t->_link;
} else {
next = t->global_link;
deleteThread(cap,t);
}
+ }
}
// The run queue now contains a bunch of ThreadKilled threads. We
tso = task->suspended_tso;
task->suspended_tso = NULL;
- tso->link = END_TSO_QUEUE;
+ tso->_link = END_TSO_QUEUE; // no write barrier reqd
debugTrace(DEBUG_sched, "thread %lu: re-entering RTS", (unsigned long)tso->id);
if (tso->why_blocked == BlockedOnCCall) {
#endif
/* We might have GC'd, mark the TSO dirty again */
- dirtyTSO(tso);
+ dirty_TSO(cap,tso);
IF_DEBUG(sanity, checkTSO(tso));
#endif
blackhole_queue = END_TSO_QUEUE;
- all_threads = END_TSO_QUEUE;
context_switch = 0;
sched_state = SCHED_RUNNING;
#endif
}
-/* ---------------------------------------------------------------------------
- Where are the roots that we know about?
-
- - all the threads on the runnable queue
- - all the threads on the blocked queue
- - all the threads on the sleeping queue
- - all the thread currently executing a _ccall_GC
- - all the "main threads"
-
- ------------------------------------------------------------------------ */
-
-/* This has to be protected either by the scheduler monitor, or by the
- garbage collection monitor (probably the latter).
- KH @ 25/10/99
-*/
-
-void
-GetRoots( evac_fn evac )
-{
- nat i;
- Capability *cap;
- Task *task;
-
-#if defined(GRAN)
- for (i=0; i<=RtsFlags.GranFlags.proc; i++) {
- if ((run_queue_hds[i] != END_TSO_QUEUE) && ((run_queue_hds[i] != NULL)))
- evac((StgClosure **)&run_queue_hds[i]);
- if ((run_queue_tls[i] != END_TSO_QUEUE) && ((run_queue_tls[i] != NULL)))
- evac((StgClosure **)&run_queue_tls[i]);
-
- if ((blocked_queue_hds[i] != END_TSO_QUEUE) && ((blocked_queue_hds[i] != NULL)))
- evac((StgClosure **)&blocked_queue_hds[i]);
- if ((blocked_queue_tls[i] != END_TSO_QUEUE) && ((blocked_queue_tls[i] != NULL)))
- evac((StgClosure **)&blocked_queue_tls[i]);
- if ((ccalling_threadss[i] != END_TSO_QUEUE) && ((ccalling_threadss[i] != NULL)))
- evac((StgClosure **)&ccalling_threads[i]);
- }
-
- markEventQueue();
-
-#else /* !GRAN */
-
- for (i = 0; i < n_capabilities; i++) {
- cap = &capabilities[i];
- evac((StgClosure **)(void *)&cap->run_queue_hd);
- evac((StgClosure **)(void *)&cap->run_queue_tl);
-#if defined(THREADED_RTS)
- evac((StgClosure **)(void *)&cap->wakeup_queue_hd);
- evac((StgClosure **)(void *)&cap->wakeup_queue_tl);
-#endif
- for (task = cap->suspended_ccalling_tasks; task != NULL;
- task=task->next) {
- debugTrace(DEBUG_sched,
- "evac'ing suspended TSO %lu", (unsigned long)task->suspended_tso->id);
- evac((StgClosure **)(void *)&task->suspended_tso);
- }
-
- }
-
-
-#if !defined(THREADED_RTS)
- evac((StgClosure **)(void *)&blocked_queue_hd);
- evac((StgClosure **)(void *)&blocked_queue_tl);
- evac((StgClosure **)(void *)&sleeping_queue);
-#endif
-#endif
-
- // evac((StgClosure **)&blackhole_queue);
-
-#if defined(THREADED_RTS) || defined(PARALLEL_HASKELL) || defined(GRAN)
- markSparkQueue(evac);
-#endif
-
-#if defined(RTS_USER_SIGNALS)
- // mark the signal handlers (signals should be already blocked)
- if (RtsFlags.MiscFlags.install_signal_handlers) {
- markSignalHandlers(evac);
- }
-#endif
-}
-
/* -----------------------------------------------------------------------------
performGC
* dead TSO's stack.
*/
tso->what_next = ThreadRelocated;
- tso->link = dest;
+ setTSOLink(cap,tso,dest);
tso->sp = (P_)&(tso->stack[tso->stack_size]);
tso->why_blocked = NotBlocked;
return dest;
}
+static StgTSO *
+threadStackUnderflow (Task *task STG_UNUSED, StgTSO *tso)
+{
+ bdescr *bd, *new_bd;
+ lnat new_tso_size_w, tso_size_w;
+ StgTSO *new_tso;
+
+ tso_size_w = tso_sizeW(tso);
+
+ if (tso_size_w < MBLOCK_SIZE_W ||
+ (nat)(tso->stack + tso->stack_size - tso->sp) > tso->stack_size / 4)
+ {
+ return tso;
+ }
+
+ // don't allow throwTo() to modify the blocked_exceptions queue
+ // while we are moving the TSO:
+ lockClosure((StgClosure *)tso);
+
+ new_tso_size_w = round_to_mblocks(tso_size_w/2);
+
+ debugTrace(DEBUG_sched, "thread %ld: reducing TSO size from %lu words to %lu",
+ tso->id, tso_size_w, new_tso_size_w);
+
+ bd = Bdescr((StgPtr)tso);
+ new_bd = splitLargeBlock(bd, new_tso_size_w / BLOCK_SIZE_W);
+
+ new_tso = (StgTSO *)new_bd->start;
+ memcpy(new_tso,tso,TSO_STRUCT_SIZE);
+ new_tso->stack_size = new_tso_size_w - TSO_STRUCT_SIZEW;
+
+ tso->what_next = ThreadRelocated;
+ tso->_link = new_tso; // no write barrier reqd: same generation
+
+ // The TSO attached to this Task may have moved, so update the
+ // pointer to it.
+ if (task->tso == tso) {
+ task->tso = new_tso;
+ }
+
+ unlockTSO(new_tso);
+ unlockTSO(tso);
+
+ IF_DEBUG(sanity,checkTSO(new_tso));
+
+ return new_tso;
+}
+
/* ---------------------------------------------------------------------------
Interrupt execution
- usually called inside a signal handler so it mustn't do anything fancy.
*prev = t;
any_woke_up = rtsTrue;
} else {
- prev = &t->link;
- t = t->link;
+ prev = &t->_link;
+ t = t->_link;
}
}
{
StgTSO *tso, *next;
Capability *cap;
+ step *step;
for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
next = tso->global_link;
- tso->global_link = all_threads;
- all_threads = tso;
+
+ step = Bdescr((P_)tso)->step;
+ tso->global_link = step->threads;
+ step->threads = tso;
+
debugTrace(DEBUG_sched, "resurrecting thread %lu", (unsigned long)tso->id);
// Wake up the thread on the Capability it was last on