/* ---------------------------------------------------------------------------
- * $Id: Schedule.c,v 1.123 2002/02/14 07:52:05 sof Exp $
+ * $Id: Schedule.c,v 1.170 2003/06/19 10:35:37 simonmar Exp $
*
* (c) The GHC Team, 1998-2000
*
#include "StgRun.h"
#include "StgStartup.h"
#include "Hooks.h"
+#define COMPILING_SCHEDULER
#include "Schedule.h"
#include "StgMiscClosures.h"
#include "Storage.h"
#include "Interpreter.h"
#include "Exception.h"
#include "Printer.h"
-#include "Main.h"
#include "Signals.h"
#include "Sanity.h"
#include "Stats.h"
-#include "Itimer.h"
+#include "Timer.h"
#include "Prelude.h"
+#include "ThreadLabels.h"
#ifdef PROFILING
#include "Proftimer.h"
#include "ProfHeap.h"
#include "OSThreads.h"
#include "Task.h"
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include <string.h>
+#include <stdlib.h>
#include <stdarg.h>
//@node Variables and Data structures, Prototypes, Includes, Main scheduling code
//@subsection Variables and Data structures
-/* Main threads:
- *
- * These are the threads which clients have requested that we run.
- *
- * In a 'threaded' build, we might have several concurrent clients all
- * waiting for results, and each one will wait on a condition variable
- * until the result is available.
- *
- * In non-SMP, clients are strictly nested: the first client calls
- * into the RTS, which might call out again to C with a _ccall_GC, and
- * eventually re-enter the RTS.
- *
- * Main threads information is kept in a linked list:
- */
-//@cindex StgMainThread
-typedef struct StgMainThread_ {
- StgTSO * tso;
- SchedulerStatus stat;
- StgClosure ** ret;
-#if defined(RTS_SUPPORTS_THREADS)
- Condition wakeup;
-#endif
- struct StgMainThread_ *link;
-} StgMainThread;
-
/* Main thread queue.
* Locks required: sched_mutex.
*/
-static StgMainThread *main_threads;
+StgMainThread *main_threads = NULL;
+
+#ifdef THREADED_RTS
+// Pointer to the thread that executes main
+// When this thread is finished, the program terminates
+// by calling shutdownHaskellAndExit.
+// It would be better to add a call to shutdownHaskellAndExit
+// to the Main.main wrapper and to remove this hack.
+StgMainThread *main_main_thread = NULL;
+#endif
/* Thread queues.
* Locks required: sched_mutex.
#else /* !GRAN */
-StgTSO *run_queue_hd, *run_queue_tl;
-StgTSO *blocked_queue_hd, *blocked_queue_tl;
-StgTSO *sleeping_queue; /* perhaps replace with a hash table? */
+StgTSO *run_queue_hd = NULL;
+StgTSO *run_queue_tl = NULL;
+StgTSO *blocked_queue_hd = NULL;
+StgTSO *blocked_queue_tl = NULL;
+StgTSO *sleeping_queue = NULL; /* perhaps replace with a hash table? */
#endif
/* Linked list of all threads.
* Used for detecting garbage collected threads.
*/
-StgTSO *all_threads;
+StgTSO *all_threads = NULL;
/* When a thread performs a safe C call (_ccall_GC, using old
* terminology), it gets put on the suspended_ccalling_threads
/* flag set by signal handler to precipitate a context switch */
//@cindex context_switch
-nat context_switch;
+nat context_switch = 0;
/* if this flag is set as well, give up execution */
//@cindex interrupted
-rtsBool interrupted;
+rtsBool interrupted = rtsFalse;
/* Next thread ID to allocate.
- * Locks required: sched_mutex
+ * Locks required: thread_id_mutex
*/
//@cindex next_thread_id
-StgThreadID next_thread_id = 1;
+static StgThreadID next_thread_id = 1;
/*
* Pointers to the state of the current thread.
/* The smallest stack size that makes any sense is:
* RESERVED_STACK_WORDS (so we can get back from the stack overflow)
* + sizeofW(StgStopFrame) (the stg_stop_thread_info frame)
- * + 1 (the realworld token for an IO thread)
* + 1 (the closure to enter)
+ * + 1 (stg_ap_v_ret)
+ * + 1 (spare slot req'd by stg_ap_v_ret)
*
* A thread with this stack will bomb immediately with a stack
* overflow, which will increase its stack size.
*/
-#define MIN_STACK_WORDS (RESERVED_STACK_WORDS + sizeofW(StgStopFrame) + 2)
+#define MIN_STACK_WORDS (RESERVED_STACK_WORDS + sizeofW(StgStopFrame) + 3)
#if defined(GRAN)
*/
StgTSO dummy_tso;
-rtsBool ready_to_gc;
+static rtsBool ready_to_gc;
+
+/*
+ * Set to TRUE when entering a shutdown state (via shutdownHaskellAndExit()) --
+ * in an MT setting, needed to signal that a worker thread shouldn't hang around
+ * in the scheduler when it is out of work.
+ */
+static rtsBool shutting_down_scheduler = rtsFalse;
void addToBlockedQueue ( StgTSO *tso );
static void schedule ( void );
void interruptStgRts ( void );
-#if defined(GRAN)
-static StgTSO * createThread_ ( nat size, rtsBool have_lock, StgInt pri );
-#else
-static StgTSO * createThread_ ( nat size, rtsBool have_lock );
-#endif
static void detectBlackHoles ( void );
Mutex sched_mutex = INIT_MUTEX_VAR;
Mutex term_mutex = INIT_MUTEX_VAR;
-
-
-
-/* thread_ready_cond: when signalled, a thread has become runnable for a
- * task to execute.
- *
- * In the non-SMP case, it also implies that the thread that is woken up has
- * exclusive access to the RTS and all its data structures (that are not
- * under sched_mutex's control).
- *
- * thread_ready_cond is signalled whenever COND_NO_THREADS_READY doesn't hold.
- *
- */
-Condition thread_ready_cond = INIT_COND_VAR;
-#if 0
-/* For documentation purposes only */
-#define COND_NO_THREADS_READY() (noCapabilities() || EMPTY_RUN_QUEUE())
-#endif
-
/*
- * To be able to make an informed decision about whether or not
- * to create a new task when making an external call, keep track of
- * the number of tasks currently blocked waiting on thread_ready_cond.
- * (if > 0 => no need for a new task, just unblock an existing one).
- *
- * waitForWork() takes care of keeping it up-to-date; Task.startTask()
- * uses its current value.
+ * A heavyweight solution to the problem of protecting
+ * the thread_id from concurrent update.
*/
-nat rts_n_waiting_tasks = 0;
+Mutex thread_id_mutex = INIT_MUTEX_VAR;
-static void waitForWork(void);
# if defined(SMP)
static Condition gc_pending_cond = INIT_COND_VAR;
#endif
#if DEBUG
-char *whatNext_strs[] = {
- "ThreadEnterGHC",
+static char *whatNext_strs[] = {
"ThreadRunGHC",
- "ThreadEnterInterp",
+ "ThreadInterpret",
"ThreadKilled",
+ "ThreadRelocated",
"ThreadComplete"
};
-
-char *threadReturnCode_strs[] = {
- "HeapOverflow", /* might also be StackOverflow */
- "StackOverflow",
- "ThreadYielding",
- "ThreadBlocked",
- "ThreadFinished"
-};
#endif
#if defined(PAR)
}
#endif
-
-
+#if defined(RTS_SUPPORTS_THREADS)
+void
+startSchedulerTask(void)
+{
+ startTask(taskStart);
+}
+#endif
//@node Main scheduling loop, Suspend and Resume, Prototypes, Main scheduling code
//@subsection Main scheduling loop
# endif
#endif
rtsBool was_interrupted = rtsFalse;
-
-#if defined(RTS_SUPPORTS_THREADS)
-schedule_start:
-#endif
+ StgTSOWhatNext prev_what_next;
-#if defined(RTS_SUPPORTS_THREADS)
ACQUIRE_LOCK(&sched_mutex);
-#endif
#if defined(RTS_SUPPORTS_THREADS)
- /* ToDo: consider SMP support */
- if ( rts_n_waiting_workers > 0 && noCapabilities() ) {
- /* (At least) one native thread is waiting to
- * deposit the result of an external call. So,
- * be nice and hand over our capability.
- */
- yieldCapability(cap);
- /* Lost our sched_mutex lock, try to re-enter the scheduler. */
- goto schedule_start;
- }
-#endif
-
-#if defined(RTS_SUPPORTS_THREADS)
- while ( noCapabilities() ) {
- waitForWork();
- }
+ waitForWorkCapability(&sched_mutex, &cap, rtsFalse);
+ IF_DEBUG(scheduler, sched_belch("worker thread (osthread %p): entering RTS", osThreadId()));
+#else
+ /* simply initialise it in the non-threaded case */
+ grabCapability(&cap);
#endif
#if defined(GRAN)
-
/* set up first event to get things going */
/* ToDo: assign costs for system setup and init MainTSO ! */
new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
IF_DEBUG(scheduler, printAllThreads());
+#if defined(RTS_SUPPORTS_THREADS)
+ /* Check to see whether there are any worker threads
+ waiting to deposit external call results. If so,
+ yield our capability */
+ yieldToReturningWorker(&sched_mutex, &cap);
+#endif
+
/* If we're interrupted (the user pressed ^C, or some other
* termination condition occurred), kill all the currently running
* threads.
*/
if (interrupted) {
IF_DEBUG(scheduler, sched_belch("interrupted"));
- deleteAllThreads();
interrupted = rtsFalse;
was_interrupted = rtsTrue;
+#if defined(RTS_SUPPORTS_THREADS)
+ // In the threaded RTS, deadlock detection doesn't work,
+ // so just exit right away.
+ prog_belch("interrupted");
+ releaseCapability(cap);
+ startTask(taskStart); // thread-safe-call to shutdownHaskellAndExit
+ RELEASE_LOCK(&sched_mutex);
+ shutdownHaskellAndExit(EXIT_SUCCESS);
+#else
+ deleteAllThreads();
+#endif
}
/* Go through the list of main threads and wake up any
{
StgMainThread *m, **prev;
prev = &main_threads;
- for (m = main_threads; m != NULL; m = m->link) {
+ for (m = main_threads; m != NULL; prev = &m->link, m = m->link) {
switch (m->tso->what_next) {
case ThreadComplete:
if (m->ret) {
- *(m->ret) = (StgClosure *)m->tso->sp[0];
+ // NOTE: return val is tso->sp[1] (see StgStartup.hc)
+ *(m->ret) = (StgClosure *)m->tso->sp[1];
}
*prev = m->link;
m->stat = Success;
broadcastCondition(&m->wakeup);
+#ifdef DEBUG
+ removeThreadLabel((StgWord)m->tso);
+#endif
+ if(m == main_main_thread)
+ {
+ releaseCapability(cap);
+ startTask(taskStart); // thread-safe-call to shutdownHaskellAndExit
+ RELEASE_LOCK(&sched_mutex);
+ shutdownHaskellAndExit(EXIT_SUCCESS);
+ }
break;
case ThreadKilled:
if (m->ret) *(m->ret) = NULL;
m->stat = Killed;
}
broadcastCondition(&m->wakeup);
+#ifdef DEBUG
+ removeThreadLabel((StgWord)m->tso);
+#endif
+ if(m == main_main_thread)
+ {
+ releaseCapability(cap);
+ startTask(taskStart); // thread-safe-call to shutdownHaskellAndExit
+ RELEASE_LOCK(&sched_mutex);
+ shutdownHaskellAndExit(EXIT_SUCCESS);
+ }
break;
default:
break;
StgMainThread *m = main_threads;
if (m->tso->what_next == ThreadComplete
|| m->tso->what_next == ThreadKilled) {
+#ifdef DEBUG
+ removeThreadLabel((StgWord)m->tso);
+#endif
main_threads = main_threads->link;
if (m->tso->what_next == ThreadComplete) {
- /* we finished successfully, fill in the return value */
- if (m->ret) { *(m->ret) = (StgClosure *)m->tso->sp[0]; };
- m->stat = Success;
- return;
+ // We finished successfully, fill in the return value
+ // NOTE: return val is tso->sp[1] (see StgStartup.hc)
+ if (m->ret) { *(m->ret) = (StgClosure *)m->tso->sp[1]; };
+ m->stat = Success;
+ return;
} else {
if (m->ret) { *(m->ret) = NULL; };
if (was_interrupted) {
#endif // SMP
/* check for signals each time around the scheduler */
-#ifndef mingw32_TARGET_OS
+#if defined(RTS_USER_SIGNALS)
if (signals_pending()) {
+ RELEASE_LOCK(&sched_mutex); /* ToDo: kill */
startSignalHandlers();
+ ACQUIRE_LOCK(&sched_mutex);
}
#endif
/* Check whether any waiting threads need to be woken up. If the
* run queue is empty, and there are no other tasks running, we
* can wait indefinitely for something to happen.
- * ToDo: what if another client comes along & requests another
- * main thread?
*/
- if ( !EMPTY_QUEUE(blocked_queue_hd) || !EMPTY_QUEUE(sleeping_queue) ) {
+ if ( !EMPTY_QUEUE(blocked_queue_hd) || !EMPTY_QUEUE(sleeping_queue)
+#if defined(RTS_SUPPORTS_THREADS) && !defined(SMP)
+ || EMPTY_RUN_QUEUE()
+#endif
+ )
+ {
awaitEvent( EMPTY_RUN_QUEUE()
#if defined(SMP)
&& allFreeCapabilities()
* If no threads are black holed, we have a deadlock situation, so
* inform all the main threads.
*/
-#ifndef PAR
- if ( EMPTY_RUN_QUEUE()
- && EMPTY_QUEUE(blocked_queue_hd)
- && EMPTY_QUEUE(sleeping_queue)
+#if !defined(PAR) && !defined(RTS_SUPPORTS_THREADS)
+ if ( EMPTY_THREAD_QUEUES()
#if defined(RTS_SUPPORTS_THREADS)
&& EMPTY_QUEUE(suspended_ccalling_threads)
#endif
/* and SMP mode ..? */
releaseCapability(cap);
#endif
- RELEASE_LOCK(&sched_mutex);
+ // Garbage collection can release some new threads due to
+ // either (a) finalizers or (b) threads resurrected because
+ // they are about to be send BlockedOnDeadMVar. Any threads
+ // thus released will be immediately runnable.
GarbageCollect(GetRoots,rtsTrue);
- ACQUIRE_LOCK(&sched_mutex);
- if ( EMPTY_QUEUE(blocked_queue_hd)
- && EMPTY_RUN_QUEUE()
- && EMPTY_QUEUE(sleeping_queue) ) {
-
- IF_DEBUG(scheduler, sched_belch("still deadlocked, checking for black holes..."));
- detectBlackHoles();
-
- /* No black holes, so probably a real deadlock. Send the
- * current main thread the Deadlock exception (or in the SMP
- * build, send *all* main threads the deadlock exception,
- * since none of them can make progress).
- */
- if ( EMPTY_RUN_QUEUE() ) {
- StgMainThread *m;
+
+ if ( !EMPTY_RUN_QUEUE() ) { goto not_deadlocked; }
+
+ IF_DEBUG(scheduler,
+ sched_belch("still deadlocked, checking for black holes..."));
+ detectBlackHoles();
+
+ if ( !EMPTY_RUN_QUEUE() ) { goto not_deadlocked; }
+
+#if defined(RTS_USER_SIGNALS)
+ /* If we have user-installed signal handlers, then wait
+ * for signals to arrive rather then bombing out with a
+ * deadlock.
+ */
#if defined(RTS_SUPPORTS_THREADS)
- for (m = main_threads; m != NULL; m = m->link) {
- switch (m->tso->why_blocked) {
- case BlockedOnBlackHole:
- raiseAsync(m->tso, (StgClosure *)NonTermination_closure);
- break;
- case BlockedOnException:
- case BlockedOnMVar:
- raiseAsync(m->tso, (StgClosure *)Deadlock_closure);
- break;
- default:
- barf("deadlock: main thread blocked in a strange way");
- }
- }
+ if ( 0 ) { /* hmm..what to do? Simply stop waiting for
+ a signal with no runnable threads (or I/O
+ suspended ones) leads nowhere quick.
+ For now, simply shut down when we reach this
+ condition.
+
+ ToDo: define precisely under what conditions
+ the Scheduler should shut down in an MT setting.
+ */
#else
- m = main_threads;
+ if ( anyUserHandlers() ) {
+#endif
+ IF_DEBUG(scheduler,
+ sched_belch("still deadlocked, waiting for signals..."));
+
+ awaitUserSignals();
+
+ // we might be interrupted...
+ if (interrupted) { continue; }
+
+ if (signals_pending()) {
+ RELEASE_LOCK(&sched_mutex);
+ startSignalHandlers();
+ ACQUIRE_LOCK(&sched_mutex);
+ }
+ ASSERT(!EMPTY_RUN_QUEUE());
+ goto not_deadlocked;
+ }
+#endif
+
+ /* Probably a real deadlock. Send the current main thread the
+ * Deadlock exception (or in the SMP build, send *all* main
+ * threads the deadlock exception, since none of them can make
+ * progress).
+ */
+ {
+ StgMainThread *m;
+#if defined(RTS_SUPPORTS_THREADS)
+ for (m = main_threads; m != NULL; m = m->link) {
switch (m->tso->why_blocked) {
case BlockedOnBlackHole:
raiseAsync(m->tso, (StgClosure *)NonTermination_closure);
default:
barf("deadlock: main thread blocked in a strange way");
}
-#endif
}
-#if defined(RTS_SUPPORTS_THREADS)
- /* ToDo: revisit conditions (and mechanism) for shutting
- down a multi-threaded world */
- if ( EMPTY_RUN_QUEUE() ) {
- IF_DEBUG(scheduler, sched_belch("all done, i think...shutting down."));
- shutdownHaskellAndExit(0);
+#else
+ m = main_threads;
+ switch (m->tso->why_blocked) {
+ case BlockedOnBlackHole:
+ raiseAsync(m->tso, (StgClosure *)NonTermination_closure);
+ break;
+ case BlockedOnException:
+ case BlockedOnMVar:
+ raiseAsync(m->tso, (StgClosure *)Deadlock_closure);
+ break;
+ default:
+ barf("deadlock: main thread blocked in a strange way");
}
#endif
- ASSERT( !EMPTY_RUN_QUEUE() );
}
+
+#if defined(RTS_SUPPORTS_THREADS)
+ /* ToDo: revisit conditions (and mechanism) for shutting
+ down a multi-threaded world */
+ IF_DEBUG(scheduler, sched_belch("all done, i think...shutting down."));
+ RELEASE_LOCK(&sched_mutex);
+ shutdownHaskell();
+ return;
+#endif
}
+ not_deadlocked:
+
+#elif defined(RTS_SUPPORTS_THREADS)
+ /* ToDo: add deadlock detection in threaded RTS */
#elif defined(PAR)
/* ToDo: add deadlock detection in GUM (similar to SMP) -- HWL */
#endif
#endif
#if defined(RTS_SUPPORTS_THREADS)
+#if defined(SMP)
/* block until we've got a thread on the run queue and a free
* capability.
*
if ( EMPTY_RUN_QUEUE() ) {
/* Give up our capability */
releaseCapability(cap);
- while ( noCapabilities() || EMPTY_RUN_QUEUE() ) {
- IF_DEBUG(scheduler, sched_belch("thread %d: waiting for work", osThreadId()));
- waitForWork();
- IF_DEBUG(scheduler, sched_belch("thread %d: work now available %d %d", osThreadId(), getFreeCapabilities(),EMPTY_RUN_QUEUE()));
+
+ /* If we're in the process of shutting down (& running the
+ * a batch of finalisers), don't wait around.
+ */
+ if ( shutting_down_scheduler ) {
+ RELEASE_LOCK(&sched_mutex);
+ return;
}
+ IF_DEBUG(scheduler, sched_belch("thread %d: waiting for work", osThreadId()));
+ waitForWorkCapability(&sched_mutex, &cap, rtsTrue);
+ IF_DEBUG(scheduler, sched_belch("thread %d: work now available", osThreadId()));
}
+#else
+ if ( EMPTY_RUN_QUEUE() ) {
+ continue; // nothing to do
+ }
+#endif
#endif
#if defined(GRAN)
-
if (RtsFlags.GranFlags.Light)
GranSimLight_enter_system(event, &ActiveTSO); // adjust ActiveTSO etc
belch("--=^ %d threads, %d sparks on [%#x]",
run_queue_len(), spark_queue_len(pool), CURRENT_PROC));
-#if 1
+# if 1
if (0 && RtsFlags.ParFlags.ParStats.Full &&
t && LastTSO && t->id != LastTSO->id &&
LastTSO->why_blocked == NotBlocked &&
emitSchedule = rtsFalse;
}
-#endif
+# endif
#else /* !GRAN && !PAR */
/* grab a thread from the run queue */
// expensive if there is lots of thread switching going on...
IF_DEBUG(sanity,checkTSO(t));
#endif
-
- grabCapability(&cap);
+
cap->r.rCurrentTSO = t;
/* context switches are now initiated by the timer signal, unless
* the user specified "context switch as often as possible", with
* +RTS -C0
*/
- if (
-#ifdef PROFILING
- RtsFlags.ProfFlags.profileInterval == 0 ||
-#endif
- (RtsFlags.ConcFlags.ctxtSwitchTicks == 0
+ if ((RtsFlags.ConcFlags.ctxtSwitchTicks == 0
&& (run_queue_hd != END_TSO_QUEUE
|| blocked_queue_hd != END_TSO_QUEUE
|| sleeping_queue != END_TSO_QUEUE)))
else
context_switch = 0;
+run_thread:
+
RELEASE_LOCK(&sched_mutex);
- IF_DEBUG(scheduler, sched_belch("-->> Running TSO %ld (%p) %s ...",
- t->id, t, whatNext_strs[t->what_next]));
+ IF_DEBUG(scheduler, sched_belch("-->> running thread %ld %s ...",
+ t->id, whatNext_strs[t->what_next]));
#ifdef PROFILING
startHeapProfTimer();
/* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
/* Run the current thread
*/
- switch (cap->r.rCurrentTSO->what_next) {
+ prev_what_next = t->what_next;
+ switch (prev_what_next) {
case ThreadKilled:
case ThreadComplete:
/* Thread already finished, return to scheduler. */
ret = ThreadFinished;
break;
- case ThreadEnterGHC:
- ret = StgRun((StgFunPtr) stg_enterStackTop, &cap->r);
- break;
case ThreadRunGHC:
ret = StgRun((StgFunPtr) stg_returnToStackTop, &cap->r);
break;
- case ThreadEnterInterp:
+ case ThreadInterpret:
ret = interpretBCO(cap);
break;
default:
#endif
ACQUIRE_LOCK(&sched_mutex);
-
-#ifdef SMP
+
+#ifdef RTS_SUPPORTS_THREADS
IF_DEBUG(scheduler,fprintf(stderr,"scheduler (task %ld): ", osThreadId()););
#elif !defined(GRAN) && !defined(PAR)
IF_DEBUG(scheduler,fprintf(stderr,"scheduler: "););
blocks = (nat)BLOCK_ROUND_UP(cap->r.rHpAlloc * sizeof(W_)) / BLOCK_SIZE;
- IF_DEBUG(scheduler,belch("--<< thread %ld (%p; %s) stopped: requesting a large block (size %d)",
- t->id, t,
- whatNext_strs[t->what_next], blocks));
+ IF_DEBUG(scheduler,belch("--<< thread %ld (%s) stopped: requesting a large block (size %d)",
+ t->id, whatNext_strs[t->what_next], blocks));
// don't do this if it would push us over the
// alloc_blocks_lim limit; we'll GC first.
}
cap->r.rCurrentNursery->u.back = bd;
- // initialise it as a nursery block
- bd->step = g0s0;
- bd->gen_no = 0;
- bd->flags = 0;
- bd->free = bd->start;
+ // initialise it as a nursery block. We initialise the
+ // step, gen_no, and flags field of *every* sub-block in
+ // this large block, because this is easier than making
+ // sure that we always find the block head of a large
+ // block whenever we call Bdescr() (eg. evacuate() and
+ // isAlive() in the GC would both have to do this, at
+ // least).
+ {
+ bdescr *x;
+ for (x = bd; x < bd + blocks; x++) {
+ x->step = g0s0;
+ x->gen_no = 0;
+ x->flags = 0;
+ }
+ }
// don't forget to update the block count in g0s0.
g0s0->n_blocks += blocks;
+ // This assert can be a killer if the app is doing lots
+ // of large block allocations.
ASSERT(countBlocks(g0s0->blocks) == g0s0->n_blocks);
// now update the nursery to point to the new block
* maybe set context_switch and wait till they all pile in,
* then have them wait on a GC condition variable.
*/
- IF_DEBUG(scheduler,belch("--<< thread %ld (%p; %s) stopped: HeapOverflow",
- t->id, t, whatNext_strs[t->what_next]));
+ IF_DEBUG(scheduler,belch("--<< thread %ld (%s) stopped: HeapOverflow",
+ t->id, whatNext_strs[t->what_next]));
threadPaused(t);
#if defined(GRAN)
ASSERT(!is_on_queue(t,CurrentProc));
// DumpGranEvent(GR_DESCHEDULE, t);
globalParStats.tot_stackover++;
#endif
- IF_DEBUG(scheduler,belch("--<< thread %ld (%p; %s) stopped, StackOverflow",
- t->id, t, whatNext_strs[t->what_next]));
+ IF_DEBUG(scheduler,belch("--<< thread %ld (%s) stopped, StackOverflow",
+ t->id, whatNext_strs[t->what_next]));
/* just adjust the stack for this thread, then pop it back
* on the run queue.
*/
* GC is finished.
*/
IF_DEBUG(scheduler,
- if (t->what_next == ThreadEnterInterp) {
- /* ToDo: or maybe a timer expired when we were in Hugs?
- * or maybe someone hit ctrl-C
- */
- belch("--<< thread %ld (%p; %s) stopped to switch to Hugs",
- t->id, t, whatNext_strs[t->what_next]);
+ if (t->what_next != prev_what_next) {
+ belch("--<< thread %ld (%s) stopped to switch evaluators",
+ t->id, whatNext_strs[t->what_next]);
} else {
- belch("--<< thread %ld (%p; %s) stopped, yielding",
- t->id, t, whatNext_strs[t->what_next]);
+ belch("--<< thread %ld (%s) stopped, yielding",
+ t->id, whatNext_strs[t->what_next]);
}
);
- threadPaused(t);
-
IF_DEBUG(sanity,
//belch("&& Doing sanity check on yielding TSO %ld.", t->id);
checkTSO(t));
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
+ // thread.
+ if (t->what_next != prev_what_next) {
+ goto run_thread;
+ }
+
+ threadPaused(t);
+
#if defined(GRAN)
ASSERT(!is_on_queue(t,CurrentProc));
//belch("&& Doing sanity check on all ThreadQueues (and their TSOs).");
checkThreadQsSanity(rtsTrue));
#endif
+
#if defined(PAR)
if (RtsFlags.ParFlags.doFairScheduling) {
/* this does round-robin scheduling; good for concurrency */
PUSH_ON_RUN_QUEUE(t);
}
#else
- /* this does round-robin scheduling; good for concurrency */
+ // this does round-robin scheduling; good for concurrency
APPEND_TO_RUN_QUEUE(t);
#endif
+
#if defined(GRAN)
/* add a ContinueThread event to actually process the thread */
new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
G_CURR_THREADQ(0));
#endif /* GRAN */
break;
-
+
case ThreadBlocked:
#if defined(GRAN)
IF_DEBUG(scheduler,
* case it'll be on the relevant queue already.
*/
IF_DEBUG(scheduler,
- fprintf(stderr, "--<< thread %d (%p) stopped: ", t->id, t);
+ fprintf(stderr, "--<< thread %d (%s) stopped: ",
+ t->id, whatNext_strs[t->what_next]);
printThreadBlockage(t);
fprintf(stderr, "\n"));
/* We also end up here if the thread kills itself with an
* uncaught exception, see Exception.hc.
*/
- IF_DEBUG(scheduler,belch("--++ thread %d (%p) finished", t->id, t));
+ IF_DEBUG(scheduler,belch("--++ thread %d (%s) finished",
+ t->id, whatNext_strs[t->what_next]));
#if defined(GRAN)
endThread(t, CurrentProc); // clean-up the thread
#elif defined(PAR)
default:
barf("schedule: invalid thread return code %d", (int)ret);
}
-
-#if defined(RTS_SUPPORTS_THREADS)
- /* I don't understand what this re-grab is doing -- sof */
- grabCapability(&cap);
-#endif
#ifdef PROFILING
- if (RtsFlags.ProfFlags.profileInterval==0 || performHeapProfile) {
+ // When we have +RTS -i0 and we're heap profiling, do a census at
+ // every GC. This lets us get repeatable runs for debugging.
+ if (performHeapProfile ||
+ (RtsFlags.ProfFlags.profileInterval==0 &&
+ RtsFlags.ProfFlags.doHeapProfile && ready_to_gc)) {
GarbageCollect(GetRoots, rtsTrue);
heapCensus();
performHeapProfile = rtsFalse;
}
#endif
+ if (ready_to_gc
#ifdef SMP
- if (ready_to_gc && allFreeCapabilities() )
-#else
- if (ready_to_gc)
+ && allFreeCapabilities()
#endif
- {
+ ) {
/* everybody back, start the GC.
* Could do it in this thread, or signal a condition var
* to do it in another thread. Either way, we need to
}
/* ---------------------------------------------------------------------------
+ * Singleton fork(). Do not copy any running threads.
+ * ------------------------------------------------------------------------- */
+
+StgInt
+forkProcess(StgTSO* tso)
+{
+#ifndef mingw32_TARGET_OS
+ pid_t pid;
+ StgTSO* t,*next;
+ StgMainThread *m;
+ rtsBool doKill;
+
+ IF_DEBUG(scheduler,sched_belch("forking!"));
+
+ pid = fork();
+ if (pid) { /* parent */
+
+ /* just return the pid */
+
+ } else { /* child */
+ /* wipe all other threads */
+ run_queue_hd = run_queue_tl = tso;
+ tso->link = END_TSO_QUEUE;
+
+ /* When clearing out the threads, we need to ensure
+ that a 'main thread' is left behind; if there isn't,
+ the Scheduler will shutdown next time it is entered.
+
+ ==> we don't kill a thread that's on the main_threads
+ list (nor the current thread.)
+
+ [ Attempts at implementing the more ambitious scheme of
+ killing the main_threads also, and then adding the
+ current thread onto the main_threads list if it wasn't
+ there already, failed -- waitThread() (for one) wasn't
+ up to it. If it proves to be desirable to also kill
+ the main threads, then this scheme will have to be
+ revisited (and fully debugged!)
+
+ -- sof 7/2002
+ ]
+ */
+ /* DO NOT TOUCH THE QUEUES directly because most of the code around
+ us is picky about finding the thread still in its queue when
+ handling the deleteThread() */
+
+ for (t = all_threads; t != END_TSO_QUEUE; t = next) {
+ next = t->link;
+
+ /* Don't kill the current thread.. */
+ if (t->id == tso->id) continue;
+ doKill=rtsTrue;
+ /* ..or a main thread */
+ for (m = main_threads; m != NULL; m = m->link) {
+ if (m->tso->id == t->id) {
+ doKill=rtsFalse;
+ break;
+ }
+ }
+ if (doKill) {
+ deleteThread(t);
+ }
+ }
+ }
+ return pid;
+#else /* mingw32 */
+ barf("forkProcess#: primop not implemented for mingw32, sorry! (%u)\n", tso->id);
+ /* pointlessly printing out the TSOs 'id' to avoid CC unused warning. */
+ return -1;
+#endif /* mingw32 */
+}
+
+/* ---------------------------------------------------------------------------
* deleteAllThreads(): kill all the live threads.
*
* This is used when we catch a user interrupt (^C), before performing
* any necessary cleanups and running finalizers.
+ *
+ * Locks: sched_mutex held.
* ------------------------------------------------------------------------- */
-void deleteAllThreads ( void )
+void
+deleteAllThreads ( void )
{
StgTSO* t, *next;
IF_DEBUG(scheduler,sched_belch("deleting all threads"));
- for (t = run_queue_hd; t != END_TSO_QUEUE; t = next) {
- next = t->link;
- deleteThread(t);
- }
- for (t = blocked_queue_hd; t != END_TSO_QUEUE; t = next) {
- next = t->link;
- deleteThread(t);
- }
- for (t = sleeping_queue; t != END_TSO_QUEUE; t = next) {
- next = t->link;
+ for (t = all_threads; t != END_TSO_QUEUE; t = next) {
+ next = t->global_link;
deleteThread(t);
- }
+ }
run_queue_hd = run_queue_tl = END_TSO_QUEUE;
blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
sleeping_queue = END_TSO_QUEUE;
* ------------------------------------------------------------------------- */
StgInt
-suspendThread( StgRegTable *reg )
+suspendThread( StgRegTable *reg,
+ rtsBool concCall
+#if !defined(RTS_SUPPORTS_THREADS) && !defined(DEBUG)
+ STG_UNUSED
+#endif
+ )
{
nat tok;
Capability *cap;
ACQUIRE_LOCK(&sched_mutex);
IF_DEBUG(scheduler,
- sched_belch("thread %d did a _ccall_gc", cap->r.rCurrentTSO->id));
+ sched_belch("thread %d did a _ccall_gc (is_concurrent: %d)", cap->r.rCurrentTSO->id,concCall));
+
+ // XXX this might not be necessary --SDM
+ cap->r.rCurrentTSO->what_next = ThreadRunGHC;
threadPaused(cap->r.rCurrentTSO);
cap->r.rCurrentTSO->link = suspended_ccalling_threads;
suspended_ccalling_threads = cap->r.rCurrentTSO;
#if defined(RTS_SUPPORTS_THREADS)
- cap->r.rCurrentTSO->why_blocked = BlockedOnCCall;
+ if(cap->r.rCurrentTSO->blocked_exceptions == NULL)
+ {
+ cap->r.rCurrentTSO->why_blocked = BlockedOnCCall;
+ cap->r.rCurrentTSO->blocked_exceptions = END_TSO_QUEUE;
+ }
+ else
+ {
+ cap->r.rCurrentTSO->why_blocked = BlockedOnCCall_NoUnblockExc;
+ }
#endif
/* Use the thread ID as the token; it should be unique */
/* Hand back capability */
releaseCapability(cap);
-#if defined(RTS_SUPPORTS_THREADS) && !defined(SMP)
+#if defined(RTS_SUPPORTS_THREADS)
/* Preparing to leave the RTS, so ensure there's a native thread/task
waiting to take over.
-
- ToDo: optimise this and only create a new task if there's a need
- for one (i.e., if there's only one Concurrent Haskell thread alive,
- there's no need to create a new task).
*/
- IF_DEBUG(scheduler, sched_belch("worker thread (%d): leaving RTS\n", tok));
- startTask(taskStart);
+ IF_DEBUG(scheduler, sched_belch("worker thread (%d, osthread %p): leaving RTS", tok, osThreadId()));
+ //if (concCall) { // implementing "safe" as opposed to "threadsafe" is more difficult
+ startTask(taskStart);
+ //}
#endif
+ /* Other threads _might_ be available for execution; signal this */
THREAD_RUNNABLE();
RELEASE_LOCK(&sched_mutex);
return tok;
}
StgRegTable *
-resumeThread( StgInt tok )
+resumeThread( StgInt tok,
+ rtsBool concCall STG_UNUSED )
{
StgTSO *tso, **prev;
Capability *cap;
#if defined(RTS_SUPPORTS_THREADS)
- /* Wait for permission to re-enter the RTS with the result.. */
- grabReturnCapability(&cap);
+ /* Wait for permission to re-enter the RTS with the result. */
+ ACQUIRE_LOCK(&sched_mutex);
+ grabReturnCapability(&sched_mutex, &cap);
+
+ IF_DEBUG(scheduler, sched_belch("worker thread (%d, osthread %p): re-entering RTS", tok, osThreadId()));
#else
grabCapability(&cap);
#endif
barf("resumeThread: thread not found");
}
tso->link = END_TSO_QUEUE;
+
+#if defined(RTS_SUPPORTS_THREADS)
+ if(tso->why_blocked == BlockedOnCCall)
+ {
+ awakenBlockedQueueNoLock(tso->blocked_exceptions);
+ tso->blocked_exceptions = NULL;
+ }
+#endif
+
/* Reset blocking status */
tso->why_blocked = NotBlocked;
- RELEASE_LOCK(&sched_mutex);
-
cap->r.rCurrentTSO = tso;
- return &cap->r;
-}
-
-
#if defined(RTS_SUPPORTS_THREADS)
-static void
-waitForWork()
-{
- rts_n_waiting_tasks++;
- waitCondition(&thread_ready_cond, &sched_mutex);
- rts_n_waiting_tasks--;
- return;
-}
+ RELEASE_LOCK(&sched_mutex);
#endif
+ return &cap->r;
+}
/* ---------------------------------------------------------------------------
* instances of Eq/Ord for ThreadIds.
* ------------------------------------------------------------------------ */
-int cmp_thread(const StgTSO *tso1, const StgTSO *tso2)
+int
+cmp_thread(StgPtr tso1, StgPtr tso2)
{
- StgThreadID id1 = tso1->id;
- StgThreadID id2 = tso2->id;
+ StgThreadID id1 = ((StgTSO *)tso1)->id;
+ StgThreadID id2 = ((StgTSO *)tso2)->id;
if (id1 < id2) return (-1);
if (id1 > id2) return 1;
*
* This is used in the implementation of Show for ThreadIds.
* ------------------------------------------------------------------------ */
-int rts_getThreadId(const StgTSO *tso)
+int
+rts_getThreadId(StgPtr tso)
+{
+ return ((StgTSO *)tso)->id;
+}
+
+#ifdef DEBUG
+void
+labelThread(StgPtr tso, char *label)
{
- return tso->id;
+ int len;
+ void *buf;
+
+ /* Caveat: Once set, you can only set the thread name to "" */
+ len = strlen(label)+1;
+ buf = stgMallocBytes(len * sizeof(char), "Schedule.c:labelThread()");
+ strncpy(buf,label,len);
+ /* Update will free the old memory for us */
+ updateThreadLabel((StgWord)tso,buf);
}
+#endif /* DEBUG */
/* ---------------------------------------------------------------------------
Create a new thread.
#if defined(GRAN)
/* currently pri (priority) is only used in a GRAN setup -- HWL */
StgTSO *
-createThread(nat stack_size, StgInt pri)
-{
- return createThread_(stack_size, rtsFalse, pri);
-}
-
-static StgTSO *
-createThread_(nat size, rtsBool have_lock, StgInt pri)
-{
+createThread(nat size, StgInt pri)
#else
StgTSO *
-createThread(nat stack_size)
-{
- return createThread_(stack_size, rtsFalse);
-}
-
-static StgTSO *
-createThread_(nat size, rtsBool have_lock)
-{
+createThread(nat size)
#endif
+{
StgTSO *tso;
nat stack_size;
#if defined(GRAN)
SET_GRAN_HDR(tso, ThisPE);
#endif
- tso->what_next = ThreadEnterGHC;
+
+ // Always start with the compiled code evaluator
+ tso->what_next = ThreadRunGHC;
/* tso->id needs to be unique. For now we use a heavyweight mutex to
* protect the increment operation on next_thread_id.
* In future, we could use an atomic increment instead.
*/
- if (!have_lock) { ACQUIRE_LOCK(&sched_mutex); }
+ ACQUIRE_LOCK(&thread_id_mutex);
tso->id = next_thread_id++;
- if (!have_lock) { RELEASE_LOCK(&sched_mutex); }
+ RELEASE_LOCK(&thread_id_mutex);
tso->why_blocked = NotBlocked;
tso->blocked_exceptions = NULL;
/* put a stop frame on the stack */
tso->sp -= sizeofW(StgStopFrame);
SET_HDR((StgClosure*)tso->sp,(StgInfoTable *)&stg_stop_thread_info,CCS_SYSTEM);
- tso->su = (StgUpdateFrame*)tso->sp;
-
// ToDo: check this
#if defined(GRAN)
tso->link = END_TSO_QUEUE;
}
else
{ threadsCreated++;
- tso = createThread_(RtsFlags.GcFlags.initialStkSize, rtsTrue);
+ tso = createThread(RtsFlags.GcFlags.initialStkSize);
if (tso==END_TSO_QUEUE)
barf("createSparkThread: Cannot create TSO");
#if defined(DIST)
}
#endif
+static SchedulerStatus waitThread_(/*out*/StgMainThread* m
+#if defined(THREADED_RTS)
+ , rtsBool blockWaiting
+#endif
+ );
+
+
/* ---------------------------------------------------------------------------
* scheduleThread()
*
* on this thread's stack before the scheduler is invoked.
* ------------------------------------------------------------------------ */
+static void scheduleThread_ (StgTSO* tso);
+
void
-scheduleThread_(StgTSO *tso
-#if defined(THREADED_RTS)
- , rtsBool createTask
-#endif
- )
+scheduleThread_(StgTSO *tso)
{
- ACQUIRE_LOCK(&sched_mutex);
+ // Precondition: sched_mutex must be held.
/* Put the new thread on the head of the runnable queue. The caller
* better push an appropriate closure on this thread's stack
* soon as we release the scheduler lock below.
*/
PUSH_ON_RUN_QUEUE(tso);
-#if defined(THREADED_RTS)
- /* If main() is scheduling a thread, don't bother creating a
- * new task.
- */
- if ( createTask ) {
- startTask(taskStart);
- }
-#endif
THREAD_RUNNABLE();
#if 0
IF_DEBUG(scheduler,printTSO(tso));
#endif
- RELEASE_LOCK(&sched_mutex);
}
void scheduleThread(StgTSO* tso)
{
+ ACQUIRE_LOCK(&sched_mutex);
+ scheduleThread_(tso);
+ RELEASE_LOCK(&sched_mutex);
+}
+
+SchedulerStatus
+scheduleWaitThread(StgTSO* tso, /*[out]*/HaskellObj* ret)
+{ // Precondition: sched_mutex must be held
+ StgMainThread *m;
+
+ m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
+ m->tso = tso;
+ m->ret = ret;
+ m->stat = NoStatus;
+#if defined(RTS_SUPPORTS_THREADS)
+ initCondition(&m->wakeup);
+#endif
+
+ /* Put the thread on the main-threads list prior to scheduling the TSO.
+ Failure to do so introduces a race condition in the MT case (as
+ identified by Wolfgang Thaller), whereby the new task/OS thread
+ created by scheduleThread_() would complete prior to the thread
+ that spawned it managed to put 'itself' on the main-threads list.
+ The upshot of it all being that the worker thread wouldn't get to
+ signal the completion of the its work item for the main thread to
+ see (==> it got stuck waiting.) -- sof 6/02.
+ */
+ IF_DEBUG(scheduler, sched_belch("waiting for thread (%d)\n", tso->id));
+
+ m->link = main_threads;
+ main_threads = m;
+
+ scheduleThread_(tso);
#if defined(THREADED_RTS)
- return scheduleThread_(tso, rtsTrue);
+ return waitThread_(m, rtsTrue);
#else
- return scheduleThread_(tso);
+ return waitThread_(m);
#endif
}
* the scheduler. */
initMutex(&sched_mutex);
initMutex(&term_mutex);
+ initMutex(&thread_id_mutex);
initCondition(&thread_ready_cond);
#endif
#if defined(RTS_SUPPORTS_THREADS)
stopTaskManager();
#endif
+ shutting_down_scheduler = rtsTrue;
}
/* -----------------------------------------------------------------------------
SchedulerStatus
waitThread(StgTSO *tso, /*out*/StgClosure **ret)
{
-#if defined(THREADED_RTS)
- return waitThread_(tso,ret, rtsFalse);
-#else
- return waitThread_(tso,ret);
-#endif
-}
-
-SchedulerStatus
-waitThread_(StgTSO *tso,
- /*out*/StgClosure **ret
-#if defined(THREADED_RTS)
- , rtsBool blockWaiting
-#endif
- )
-{
StgMainThread *m;
SchedulerStatus stat;
- ACQUIRE_LOCK(&sched_mutex);
-
m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
-
m->tso = tso;
m->ret = ret;
m->stat = NoStatus;
initCondition(&m->wakeup);
#endif
+ /* see scheduleWaitThread() comment */
+ ACQUIRE_LOCK(&sched_mutex);
m->link = main_threads;
main_threads = m;
+ IF_DEBUG(scheduler, sched_belch("waiting for thread %d", tso->id));
+#if defined(THREADED_RTS)
+ stat = waitThread_(m, rtsFalse);
+#else
+ stat = waitThread_(m);
+#endif
+ RELEASE_LOCK(&sched_mutex);
+ return stat;
+}
+
+static
+SchedulerStatus
+waitThread_(StgMainThread* m
+#if defined(THREADED_RTS)
+ , rtsBool blockWaiting
+#endif
+ )
+{
+ SchedulerStatus stat;
+
+ // Precondition: sched_mutex must be held.
IF_DEBUG(scheduler, sched_belch("== scheduler: new main thread (%d)\n", m->tso->id));
#if defined(RTS_SUPPORTS_THREADS)
* gets to enter the RTS directly without going via another
* task/thread.
*/
+ main_main_thread = m;
RELEASE_LOCK(&sched_mutex);
schedule();
+ ACQUIRE_LOCK(&sched_mutex);
+ main_main_thread = NULL;
ASSERT(m->stat != NoStatus);
} else
# endif
{
- IF_DEBUG(scheduler, sched_belch("sfoo"));
do {
waitCondition(&m->wakeup, &sched_mutex);
} while (m->stat == NoStatus);
procStatus[MainProc] = Busy; // status of main PE
CurrentProc = MainProc; // PE to run it on
+ RELEASE_LOCK(&sched_mutex);
schedule();
#else
RELEASE_LOCK(&sched_mutex);
IF_DEBUG(scheduler, fprintf(stderr, "== scheduler: main thread (%d) finished\n",
m->tso->id));
- free(m);
-
-#if defined(THREADED_RTS)
- if (blockWaiting)
-#endif
- RELEASE_LOCK(&sched_mutex);
+ stgFree(m);
+ // Postcondition: sched_mutex still held
return stat;
}
void
GetRoots(evac_fn evac)
{
- StgMainThread *m;
-
#if defined(GRAN)
{
nat i;
}
#endif
- for (m = main_threads; m != NULL; m = m->link) {
- evac((StgClosure **)&m->tso);
- }
if (suspended_ccalling_threads != END_TSO_QUEUE) {
evac((StgClosure **)&suspended_ccalling_threads);
}
#if defined(PAR) || defined(GRAN)
markSparkQueue(evac);
#endif
+
+#if defined(RTS_USER_SIGNALS)
+ // mark the signal handlers (signals should be already blocked)
+ markSignalHandlers(evac);
+#endif
+
+ // main threads which have completed need to be retained until they
+ // are dealt with in the main scheduler loop. They won't be
+ // retained any other way: the GC will drop them from the
+ // all_threads list, so we have to be careful to treat them as roots
+ // here.
+ {
+ StgMainThread *m;
+ for (m = main_threads; m != NULL; m = m->link) {
+ switch (m->tso->what_next) {
+ case ThreadComplete:
+ case ThreadKilled:
+ evac((StgClosure **)&m->tso);
+ break;
+ default:
+ break;
+ }
+ }
+ }
}
/* -----------------------------------------------------------------------------
This needs to be protected by the GC condition variable above. KH.
-------------------------------------------------------------------------- */
-void (*extra_roots)(evac_fn);
+static void (*extra_roots)(evac_fn);
void
performGC(void)
{
+ /* Obligated to hold this lock upon entry */
+ ACQUIRE_LOCK(&sched_mutex);
GarbageCollect(GetRoots,rtsFalse);
+ RELEASE_LOCK(&sched_mutex);
}
void
performMajorGC(void)
{
+ ACQUIRE_LOCK(&sched_mutex);
GarbageCollect(GetRoots,rtsTrue);
+ RELEASE_LOCK(&sched_mutex);
}
static void
void
performGCWithRoots(void (*get_roots)(evac_fn))
{
+ ACQUIRE_LOCK(&sched_mutex);
extra_roots = get_roots;
GarbageCollect(AllRoots,rtsFalse);
+ RELEASE_LOCK(&sched_mutex);
}
/* -----------------------------------------------------------------------------
static StgTSO *
threadStackOverflow(StgTSO *tso)
{
- nat new_stack_size, new_tso_size, diff, stack_words;
+ nat new_stack_size, new_tso_size, stack_words;
StgPtr new_sp;
StgTSO *dest;
memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
/* relocate the stack pointers... */
- diff = (P_)new_sp - (P_)tso->sp; /* In *words* */
- dest->su = (StgUpdateFrame *) ((P_)dest->su + diff);
- dest->sp = new_sp;
+ dest->sp = new_sp;
dest->stack_size = new_stack_size;
- /* and relocate the update frame list */
- relocate_stack(dest, diff);
-
/* Mark the old TSO as relocated. We have to check for relocated
* TSOs in the garbage collector and any primops that deal with TSOs.
*
- * It's important to set the sp and su values to just beyond the end
+ * It's important to set the sp value to just beyond the end
* of the stack, so we don't attempt to scavenge any part of the
* dead TSO's stack.
*/
tso->what_next = ThreadRelocated;
tso->link = dest;
tso->sp = (P_)&(tso->stack[tso->stack_size]);
- tso->su = (StgUpdateFrame *)tso->sp;
tso->why_blocked = NotBlocked;
dest->mut_link = NULL;
}
#else /* !GRAN && !PAR */
+
+#ifdef RTS_SUPPORTS_THREADS
+void
+awakenBlockedQueueNoLock(StgTSO *tso)
+{
+ while (tso != END_TSO_QUEUE) {
+ tso = unblockOneLocked(tso);
+ }
+}
+#endif
+
void
awakenBlockedQueue(StgTSO *tso)
{
NB: only the type of the blocking queue is different in GranSim and GUM
the operations on the queue-elements are the same
long live polymorphism!
+
+ Locks: sched_mutex is held upon entry and exit.
+
*/
static void
unblockThread(StgTSO *tso)
{
StgBlockingQueueElement *t, **last;
- ACQUIRE_LOCK(&sched_mutex);
switch (tso->why_blocked) {
case NotBlocked:
tso->why_blocked = NotBlocked;
tso->block_info.closure = NULL;
PUSH_ON_RUN_QUEUE(tso);
- RELEASE_LOCK(&sched_mutex);
}
#else
static void
unblockThread(StgTSO *tso)
{
StgTSO *t, **last;
+
+ /* To avoid locking unnecessarily. */
+ if (tso->why_blocked == NotBlocked) {
+ return;
+ }
- ACQUIRE_LOCK(&sched_mutex);
switch (tso->why_blocked) {
- case NotBlocked:
- return; /* not blocked */
-
case BlockedOnMVar:
ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
{
tso->why_blocked = NotBlocked;
tso->block_info.closure = NULL;
PUSH_ON_RUN_QUEUE(tso);
- RELEASE_LOCK(&sched_mutex);
}
#endif
* the top of the stack.
*
* How exactly do we save all the active computations? We create an
- * AP_UPD for every UpdateFrame on the stack. Entering one of these
- * AP_UPDs pushes everything from the corresponding update frame
+ * AP_STACK for every UpdateFrame on the stack. Entering one of these
+ * AP_STACKs pushes everything from the corresponding update frame
* upwards onto the stack. (Actually, it pushes everything up to the
- * next update frame plus a pointer to the next AP_UPD object.
- * Entering the next AP_UPD object pushes more onto the stack until we
- * reach the last AP_UPD object - at which point the stack should look
+ * next update frame plus a pointer to the next AP_STACK object.
+ * Entering the next AP_STACK object pushes more onto the stack until we
+ * reach the last AP_STACK object - at which point the stack should look
* exactly as it did when we killed the TSO and we can continue
* execution by entering the closure on top of the stack.
*
* CATCH_FRAME on the stack. In either case, we strip the entire
* stack and replace the thread with a zombie.
*
+ * Locks: sched_mutex held upon entry nor exit.
+ *
* -------------------------------------------------------------------------- */
void
}
void
+raiseAsyncWithLock(StgTSO *tso, StgClosure *exception)
+{
+ /* When raising async exs from contexts where sched_mutex isn't held;
+ use raiseAsyncWithLock(). */
+ ACQUIRE_LOCK(&sched_mutex);
+ raiseAsync(tso,exception);
+ RELEASE_LOCK(&sched_mutex);
+}
+
+void
raiseAsync(StgTSO *tso, StgClosure *exception)
{
- StgUpdateFrame* su = tso->su;
- StgPtr sp = tso->sp;
+ StgRetInfoTable *info;
+ StgPtr sp;
- /* Thread already dead? */
- if (tso->what_next == ThreadComplete || tso->what_next == ThreadKilled) {
- return;
- }
-
- IF_DEBUG(scheduler, sched_belch("raising exception in thread %ld.", tso->id));
-
- /* Remove it from any blocking queues */
- unblockThread(tso);
-
- /* The stack freezing code assumes there's a closure pointer on
- * the top of the stack. This isn't always the case with compiled
- * code, so we have to push a dummy closure on the top which just
- * returns to the next return address on the stack.
- */
- if ( LOOKS_LIKE_GHC_INFO((void*)*sp) ) {
- *(--sp) = (W_)&stg_dummy_ret_closure;
- }
-
- while (1) {
- nat words = ((P_)su - (P_)sp) - 1;
- nat i;
- StgAP_UPD * ap;
-
- /* If we find a CATCH_FRAME, and we've got an exception to raise,
- * then build PAP(handler,exception,realworld#), and leave it on
- * top of the stack ready to enter.
- */
- if (get_itbl(su)->type == CATCH_FRAME && exception != NULL) {
- StgCatchFrame *cf = (StgCatchFrame *)su;
- /* we've got an exception to raise, so let's pass it to the
- * handler in this frame.
- */
- ap = (StgAP_UPD *)allocate(sizeofW(StgPAP) + 2);
- TICK_ALLOC_UPD_PAP(3,0);
- SET_HDR(ap,&stg_PAP_info,cf->header.prof.ccs);
-
- ap->n_args = 2;
- ap->fun = cf->handler; /* :: Exception -> IO a */
- ap->payload[0] = exception;
- ap->payload[1] = ARG_TAG(0); /* realworld token */
-
- /* throw away the stack from Sp up to and including the
- * CATCH_FRAME.
- */
- sp = (P_)su + sizeofW(StgCatchFrame) - 1;
- tso->su = cf->link;
-
- /* Restore the blocked/unblocked state for asynchronous exceptions
- * at the CATCH_FRAME.
- *
- * If exceptions were unblocked at the catch, arrange that they
- * are unblocked again after executing the handler by pushing an
- * unblockAsyncExceptions_ret stack frame.
- */
- if (!cf->exceptions_blocked) {
- *(sp--) = (W_)&stg_unblockAsyncExceptionszh_ret_info;
- }
-
- /* Ensure that async exceptions are blocked when running the handler.
- */
- if (tso->blocked_exceptions == NULL) {
- tso->blocked_exceptions = END_TSO_QUEUE;
- }
-
- /* Put the newly-built PAP on top of the stack, ready to execute
- * when the thread restarts.
- */
- sp[0] = (W_)ap;
- tso->sp = sp;
- tso->what_next = ThreadEnterGHC;
- IF_DEBUG(sanity, checkTSO(tso));
- return;
+ // Thread already dead?
+ if (tso->what_next == ThreadComplete || tso->what_next == ThreadKilled) {
+ return;
}
- /* First build an AP_UPD consisting of the stack chunk above the
- * current update frame, with the top word on the stack as the
- * fun field.
- */
- ap = (StgAP_UPD *)allocate(AP_sizeW(words));
+ IF_DEBUG(scheduler,
+ sched_belch("raising exception in thread %ld.", tso->id));
- ASSERT(words >= 0);
+ // Remove it from any blocking queues
+ unblockThread(tso);
+
+ sp = tso->sp;
- ap->n_args = words;
- ap->fun = (StgClosure *)sp[0];
- sp++;
- for(i=0; i < (nat)words; ++i) {
- ap->payload[i] = (StgClosure *)*sp++;
+ // The stack freezing code assumes there's a closure pointer on
+ // the top of the stack, so we have to arrange that this is the case...
+ //
+ if (sp[0] == (W_)&stg_enter_info) {
+ sp++;
+ } else {
+ sp--;
+ sp[0] = (W_)&stg_dummy_ret_closure;
}
-
- switch (get_itbl(su)->type) {
-
- case UPDATE_FRAME:
- {
- SET_HDR(ap,&stg_AP_UPD_info,su->header.prof.ccs /* ToDo */);
- TICK_ALLOC_UP_THK(words+1,0);
-
- IF_DEBUG(scheduler,
- fprintf(stderr, "scheduler: Updating ");
- printPtr((P_)su->updatee);
- fprintf(stderr, " with ");
- printObj((StgClosure *)ap);
- );
-
- /* Replace the updatee with an indirection - happily
- * this will also wake up any threads currently
- * waiting on the result.
- *
- * Warning: if we're in a loop, more than one update frame on
- * the stack may point to the same object. Be careful not to
- * overwrite an IND_OLDGEN in this case, because we'll screw
- * up the mutable lists. To be on the safe side, don't
- * overwrite any kind of indirection at all. See also
- * threadSqueezeStack in GC.c, where we have to make a similar
- * check.
- */
- if (!closure_IND(su->updatee)) {
- UPD_IND_NOLOCK(su->updatee,ap); /* revert the black hole */
- }
- su = su->link;
- sp += sizeofW(StgUpdateFrame) -1;
- sp[0] = (W_)ap; /* push onto stack */
- break;
- }
- case CATCH_FRAME:
- {
- StgCatchFrame *cf = (StgCatchFrame *)su;
- StgClosure* o;
-
- /* We want a PAP, not an AP_UPD. Fortunately, the
- * layout's the same.
- */
- SET_HDR(ap,&stg_PAP_info,su->header.prof.ccs /* ToDo */);
- TICK_ALLOC_UPD_PAP(words+1,0);
+ while (1) {
+ nat i;
+
+ // 1. Let the top of the stack be the "current closure"
+ //
+ // 2. Walk up the stack until we find either an UPDATE_FRAME or a
+ // CATCH_FRAME.
+ //
+ // 3. If it's an UPDATE_FRAME, then make an AP_STACK containing the
+ // current closure applied to the chunk of stack up to (but not
+ // including) the update frame. This closure becomes the "current
+ // closure". Go back to step 2.
+ //
+ // 4. If it's a CATCH_FRAME, then leave the exception handler on
+ // top of the stack applied to the exception.
+ //
+ // 5. If it's a STOP_FRAME, then kill the thread.
- /* now build o = FUN(catch,ap,handler) */
- o = (StgClosure *)allocate(sizeofW(StgClosure)+2);
- TICK_ALLOC_FUN(2,0);
- SET_HDR(o,&stg_catch_info,su->header.prof.ccs /* ToDo */);
- o->payload[0] = (StgClosure *)ap;
- o->payload[1] = cf->handler;
+ StgPtr frame;
- IF_DEBUG(scheduler,
- fprintf(stderr, "scheduler: Built ");
- printObj((StgClosure *)o);
- );
-
- /* pop the old handler and put o on the stack */
- su = cf->link;
- sp += sizeofW(StgCatchFrame) - 1;
- sp[0] = (W_)o;
- break;
- }
-
- case SEQ_FRAME:
- {
- StgSeqFrame *sf = (StgSeqFrame *)su;
- StgClosure* o;
+ frame = sp + 1;
+ info = get_ret_itbl((StgClosure *)frame);
- SET_HDR(ap,&stg_PAP_info,su->header.prof.ccs /* ToDo */);
- TICK_ALLOC_UPD_PAP(words+1,0);
+ while (info->i.type != UPDATE_FRAME
+ && (info->i.type != CATCH_FRAME || exception == NULL)
+ && info->i.type != STOP_FRAME) {
+ frame += stack_frame_sizeW((StgClosure *)frame);
+ info = get_ret_itbl((StgClosure *)frame);
+ }
- /* now build o = FUN(seq,ap) */
- o = (StgClosure *)allocate(sizeofW(StgClosure)+1);
- TICK_ALLOC_SE_THK(1,0);
- SET_HDR(o,&stg_seq_info,su->header.prof.ccs /* ToDo */);
- o->payload[0] = (StgClosure *)ap;
+ switch (info->i.type) {
+
+ case CATCH_FRAME:
+ // If we find a CATCH_FRAME, and we've got an exception to raise,
+ // then build the THUNK raise(exception), and leave it on
+ // top of the CATCH_FRAME ready to enter.
+ //
+ {
+#ifdef PROFILING
+ StgCatchFrame *cf = (StgCatchFrame *)frame;
+#endif
+ StgClosure *raise;
+
+ // we've got an exception to raise, so let's pass it to the
+ // handler in this frame.
+ //
+ raise = (StgClosure *)allocate(sizeofW(StgClosure)+1);
+ TICK_ALLOC_SE_THK(1,0);
+ SET_HDR(raise,&stg_raise_info,cf->header.prof.ccs);
+ raise->payload[0] = exception;
+
+ // throw away the stack from Sp up to the CATCH_FRAME.
+ //
+ sp = frame - 1;
+
+ /* Ensure that async excpetions are blocked now, so we don't get
+ * a surprise exception before we get around to executing the
+ * handler.
+ */
+ if (tso->blocked_exceptions == NULL) {
+ tso->blocked_exceptions = END_TSO_QUEUE;
+ }
+
+ /* Put the newly-built THUNK on top of the stack, ready to execute
+ * when the thread restarts.
+ */
+ sp[0] = (W_)raise;
+ sp[-1] = (W_)&stg_enter_info;
+ tso->sp = sp-1;
+ tso->what_next = ThreadRunGHC;
+ IF_DEBUG(sanity, checkTSO(tso));
+ return;
+ }
- IF_DEBUG(scheduler,
- fprintf(stderr, "scheduler: Built ");
- printObj((StgClosure *)o);
- );
+ case UPDATE_FRAME:
+ {
+ StgAP_STACK * ap;
+ nat words;
+
+ // First build an AP_STACK consisting of the stack chunk above the
+ // current update frame, with the top word on the stack as the
+ // fun field.
+ //
+ words = frame - sp - 1;
+ ap = (StgAP_STACK *)allocate(PAP_sizeW(words));
+
+ ap->size = words;
+ ap->fun = (StgClosure *)sp[0];
+ sp++;
+ for(i=0; i < (nat)words; ++i) {
+ ap->payload[i] = (StgClosure *)*sp++;
+ }
+
+ SET_HDR(ap,&stg_AP_STACK_info,
+ ((StgClosure *)frame)->header.prof.ccs /* ToDo */);
+ TICK_ALLOC_UP_THK(words+1,0);
+
+ IF_DEBUG(scheduler,
+ fprintf(stderr, "scheduler: Updating ");
+ printPtr((P_)((StgUpdateFrame *)frame)->updatee);
+ fprintf(stderr, " with ");
+ printObj((StgClosure *)ap);
+ );
+
+ // Replace the updatee with an indirection - happily
+ // this will also wake up any threads currently
+ // waiting on the result.
+ //
+ // Warning: if we're in a loop, more than one update frame on
+ // the stack may point to the same object. Be careful not to
+ // overwrite an IND_OLDGEN in this case, because we'll screw
+ // up the mutable lists. To be on the safe side, don't
+ // overwrite any kind of indirection at all. See also
+ // threadSqueezeStack in GC.c, where we have to make a similar
+ // check.
+ //
+ if (!closure_IND(((StgUpdateFrame *)frame)->updatee)) {
+ // revert the black hole
+ UPD_IND_NOLOCK(((StgUpdateFrame *)frame)->updatee,ap);
+ }
+ sp += sizeofW(StgUpdateFrame) - 1;
+ sp[0] = (W_)ap; // push onto stack
+ break;
+ }
- /* pop the old handler and put o on the stack */
- su = sf->link;
- sp += sizeofW(StgSeqFrame) - 1;
- sp[0] = (W_)o;
- break;
- }
-
- case STOP_FRAME:
- /* We've stripped the entire stack, the thread is now dead. */
- sp += sizeofW(StgStopFrame) - 1;
- sp[0] = (W_)exception; /* save the exception */
- tso->what_next = ThreadKilled;
- tso->su = (StgUpdateFrame *)(sp+1);
- tso->sp = sp;
- return;
-
- default:
- barf("raiseAsync");
+ case STOP_FRAME:
+ // We've stripped the entire stack, the thread is now dead.
+ sp += sizeofW(StgStopFrame);
+ tso->what_next = ThreadKilled;
+ tso->sp = sp;
+ return;
+
+ default:
+ barf("raiseAsync");
+ }
}
- }
- barf("raiseAsync");
+ barf("raiseAsync");
}
/* -----------------------------------------------------------------------------
up and sent a signal: BlockedOnDeadMVar if the thread was blocked
on an MVar, or NonTermination if the thread was blocked on a Black
Hole.
+
+ Locks: sched_mutex isn't held upon entry nor exit.
-------------------------------------------------------------------------- */
void
switch (tso->why_blocked) {
case BlockedOnMVar:
case BlockedOnException:
+ /* Called by GC - sched_mutex lock is currently held. */
raiseAsync(tso,(StgClosure *)BlockedOnDeadMVar_closure);
break;
case BlockedOnBlackHole:
*
* This is only done in a deadlock situation in order to avoid
* performance overhead in the normal case.
+ *
+ * Locks: sched_mutex is held upon entry and exit.
* -------------------------------------------------------------------------- */
static void
detectBlackHoles( void )
{
- StgTSO *t = all_threads;
- StgUpdateFrame *frame;
+ StgTSO *tso = all_threads;
+ StgClosure *frame;
StgClosure *blocked_on;
+ StgRetInfoTable *info;
- for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
+ for (tso = all_threads; tso != END_TSO_QUEUE; tso = tso->global_link) {
- while (t->what_next == ThreadRelocated) {
- t = t->link;
- ASSERT(get_itbl(t)->type == TSO);
+ while (tso->what_next == ThreadRelocated) {
+ tso = tso->link;
+ ASSERT(get_itbl(tso)->type == TSO);
}
- if (t->why_blocked != BlockedOnBlackHole) {
+ if (tso->why_blocked != BlockedOnBlackHole) {
continue;
}
+ blocked_on = tso->block_info.closure;
- blocked_on = t->block_info.closure;
-
- for (frame = t->su; ; frame = frame->link) {
- switch (get_itbl(frame)->type) {
+ frame = (StgClosure *)tso->sp;
+ while(1) {
+ info = get_ret_itbl(frame);
+ switch (info->i.type) {
case UPDATE_FRAME:
- if (frame->updatee == blocked_on) {
+ if (((StgUpdateFrame *)frame)->updatee == blocked_on) {
/* We are blocking on one of our own computations, so
* send this thread the NonTermination exception.
*/
IF_DEBUG(scheduler,
- sched_belch("thread %d is blocked on itself", t->id));
- raiseAsync(t, (StgClosure *)NonTermination_closure);
+ sched_belch("thread %d is blocked on itself", tso->id));
+ raiseAsync(tso, (StgClosure *)NonTermination_closure);
goto done;
}
- else {
- continue;
- }
-
- case CATCH_FRAME:
- case SEQ_FRAME:
- continue;
+ frame = (StgClosure *) ((StgUpdateFrame *)frame + 1);
+ continue;
+
case STOP_FRAME:
- break;
- }
- break;
- }
+ goto done;
- done: ;
- }
+ // normal stack frames; do nothing except advance the pointer
+ default:
+ (StgPtr)frame += stack_frame_sizeW(frame);
+ }
+ }
+ done: ;
+ }
}
//@node Debugging Routines, Index, Exception Handling Routines, Main scheduling code
//@subsection Debugging Routines
/* -----------------------------------------------------------------------------
- Debugging: why is a thread blocked
+ * Debugging: why is a thread blocked
+ * [Also provides useful information when debugging threaded programs
+ * at the Haskell source code level, so enable outside of DEBUG. --sof 7/02]
-------------------------------------------------------------------------- */
-#ifdef DEBUG
-
+static
void
printThreadBlockage(StgTSO *tso)
{
case BlockedOnCCall:
fprintf(stderr,"is blocked on an external call");
break;
+ case BlockedOnCCall_NoUnblockExc:
+ fprintf(stderr,"is blocked on an external call (exceptions were already blocked)");
+ break;
#endif
default:
barf("printThreadBlockage: strange tso->why_blocked: %d for TSO %d (%d)",
}
}
+static
void
printThreadStatus(StgTSO *tso)
{
printAllThreads(void)
{
StgTSO *t;
+ void *label;
# if defined(GRAN)
char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN];
ullong_format_string(TIME_ON_PROC(CurrentProc),
time_string, rtsFalse/*no commas!*/);
- sched_belch("all threads at [%s]:", time_string);
+ fprintf(stderr, "all threads at [%s]:\n", time_string);
# elif defined(PAR)
char time_string[TIME_STR_LEN], node_str[NODE_STR_LEN];
ullong_format_string(CURRENT_TIME,
time_string, rtsFalse/*no commas!*/);
- sched_belch("all threads at [%s]:", time_string);
+ fprintf(stderr,"all threads at [%s]:\n", time_string);
# else
- sched_belch("all threads:");
+ fprintf(stderr,"all threads:\n");
# endif
for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
- fprintf(stderr, "\tthread %d ", t->id);
+ fprintf(stderr, "\tthread %d @ %p ", t->id, (void *)t);
+ label = lookupThreadLabel((StgWord)t);
+ if (label) fprintf(stderr,"[\"%s\"] ",(char *)label);
printThreadStatus(t);
fprintf(stderr,"\n");
}
}
+#ifdef DEBUG
+
/*
Print a whole blocking queue attached to node (debugging only).
*/
#endif
vfprintf(stderr, s, ap);
fprintf(stderr, "\n");
+ va_end(ap);
}
#endif /* DEBUG */
//@subsection Index
//@index
-//* MainRegTable:: @cindex\s-+MainRegTable
//* StgMainThread:: @cindex\s-+StgMainThread
//* awaken_blocked_queue:: @cindex\s-+awaken_blocked_queue
//* blocked_queue_hd:: @cindex\s-+blocked_queue_hd
//* schedule:: @cindex\s-+schedule
//* take_off_run_queue:: @cindex\s-+take_off_run_queue
//* term_mutex:: @cindex\s-+term_mutex
-//* thread_ready_cond:: @cindex\s-+thread_ready_cond
//@end index
projects / ghc-hetmet.git / blobdiff