SymbolTlValue(GC_PENDING, self) == NIL));
}
+#ifdef LISP_FEATURE_SB_THRUPTION
+static inline int
+thread_may_thrupt(os_context_t *ctx)
+{
+ struct thread * self = arch_os_get_current_thread();
+ /* Thread may be interrupted if all of these are true:
+ * 1) Deferrables are unblocked in the context of the signal that
+ * went into the safepoint. -- Otherwise the surrounding code
+ * didn't want to be interrupted by a signal, so presumably it didn't
+ * want to be INTERRUPT-THREADed either.
+ * (See interrupt_handle_pending for an exception.)
+ * 2) On POSIX: There is no pending signal. This is important even
+ * after checking the sigmask, since we could be in the
+ * handle_pending trap following re-enabling of interrupts.
+ * Signals are unblocked in that case, but the signal is still
+ * pending; we want to run GC before handling the signal and
+ * therefore entered this safepoint. But the thruption would call
+ * ALLOW-WITH-INTERRUPTS, and could re-enter the handle_pending
+ * trap, leading to recursion.
+ * 3) INTERRUPTS_ENABLED is non-nil.
+ * 4) No GC pending; it takes precedence.
+ * Note that we are in a safepoint here, which is always outside of PA. */
+
+ if (SymbolValue(INTERRUPTS_ENABLED, self) == NIL)
+ return 0;
+
+ if (SymbolValue(GC_PENDING, self) != NIL)
+ return 0;
+
+ if (SymbolValue(STOP_FOR_GC_PENDING, self) != NIL)
+ return 0;
+
+#ifdef LISP_FEATURE_WIN32
+ if (deferrables_blocked_p(&self->os_thread->blocked_signal_set))
+ return 0;
+#else
+ /* ctx is NULL if the caller wants to ignore the sigmask. */
+ if (ctx && deferrables_blocked_p(os_context_sigmask_addr(ctx)))
+ return 0;
+ if (SymbolValue(INTERRUPT_PENDING, self) != NIL)
+ return 0;
+#endif
+
+ if (SymbolValue(RESTART_CLUSTERS, self) == NIL)
+ /* This special case prevents TERMINATE-THREAD from hitting
+ * during INITIAL-THREAD-FUNCTION before it's ready. Curiously,
+ * deferrables are already unblocked there. Further
+ * investigation may be in order. */
+ return 0;
+
+ return 1;
+}
+
+// returns 0 if skipped, 1 otherwise
+int
+check_pending_thruptions(os_context_t *ctx)
+{
+ struct thread *p = arch_os_get_current_thread();
+
+ gc_assert(!os_get_csp(p));
+
+ if (!thread_may_thrupt(ctx))
+ return 0;
+ if (SymbolValue(THRUPTION_PENDING, p) == NIL)
+ return 0;
+ SetSymbolValue(THRUPTION_PENDING, NIL, p);
+
+ sigset_t oldset;
+ block_deferrable_signals(0, &oldset);
+
+ funcall0(StaticSymbolFunction(RUN_INTERRUPTION));
+
+ pthread_sigmask(SIG_SETMASK, &oldset, 0);
+ return 1;
+}
+#endif
+
int
on_stack_p(struct thread *th, void *esp)
{
work without thundering herd. */
int stopped;
+ /* Thruption flag: Iff true, current STW initiator is delivering
+ thruptions and not GCing. */
+ boolean thruption;
+
} gc_dispatcher = {
/* mutexes lazy initialized, other data initially zeroed */
.mx_gpunmapped = PTHREAD_MUTEX_INITIALIZER,
in progress, begin it by unmapping GC page, and record current
thread as STW initiator.
+ `thruption' flag affects some subtleties of stop/start methods:
+ waiting for other threads allowing GC; setting and clearing
+ STOP_FOR_GC_PENDING, GC_PENDING, THRUPTION_PENDING, etc.
+
Return true if current thread becomes a GC initiator, or already
_is_ a STW initiator.
the right' to stop the world as early as it wants. */
static inline boolean
-maybe_become_stw_initiator()
+maybe_become_stw_initiator(boolean thruption)
{
struct thread* self = arch_os_get_current_thread();
odxprint(misc,"NULL STW IN GPTRANSITION, REPLACING");
/* Then we are... */
gc_dispatcher.th_stw_initiator = self;
+ gc_dispatcher.thruption = thruption;
/* hold mx_gcing until we restart the world */
pthread_mutex_lock(&gc_dispatcher.mx_gcing);
gc_stop_the_world()
{
struct thread* self = arch_os_get_current_thread(), *p;
+ boolean thruption;
if (SymbolTlValue(GC_INHIBIT,self)!=T) {
/* If GC is enabled, this thread may wait for current STW
initiator without causing deadlock. */
- if (!maybe_become_stw_initiator()) {
+ if (!maybe_become_stw_initiator(0)) {
pthread_mutex_lock(&gc_dispatcher.mx_gcing);
- maybe_become_stw_initiator();
+ maybe_become_stw_initiator(0);
pthread_mutex_unlock(&gc_dispatcher.mx_gcing);
}
/* Now _this thread_ should be STW initiator */
gc_assert(self == gc_dispatcher.th_stw_initiator);
} else {
/* GC inhibited; e.g. we are inside SUB-GC */
- if (!maybe_become_stw_initiator()) {
+ if (!maybe_become_stw_initiator(0)) {
/* Some trouble. Inside SUB-GC, holding the Lisp-side
mutex, but some other thread is stopping the world. */
- {
+ if (gc_dispatcher.thruption) {
+ /* Thruption. Wait until it's delivered */
+ pthread_mutex_lock(&gc_dispatcher.mx_gcing);
+ /* Warning: mx_gcing is held recursively. */
+ gc_assert(maybe_become_stw_initiator(0));
+ pthread_mutex_unlock(&gc_dispatcher.mx_gcing);
+ } else {
/* In SUB-GC, holding mutex; other thread wants to
GC. */
if (gc_dispatcher.th_subgc == self) {
}
}
}
+ thruption = gc_dispatcher.thruption; /* Thruption or GC? */
if (!gc_dispatcher.stopped++) {
/* Outermost stop: signal other threads */
pthread_mutex_lock(&all_threads_lock);
pthread_mutex_unlock(p_qrl);
} else {
/* In C; we just disabled writing. */
- {
+ if (!thruption) {
if (SymbolTlValue(GC_INHIBIT,p)==T) {
/* GC inhibited there */
SetTlSymbolValue(STOP_FOR_GC_PENDING,T,p);
odxprint(safepoints,"after remapping GC page %p",self);
SetTlSymbolValue(STOP_FOR_GC_PENDING,NIL,self);
- {
+ if (!thruption) {
struct thread* priority_gc = NULL;
for_each_thread(p) {
if (p==self)
gc_start_the_world()
{
struct thread* self = arch_os_get_current_thread(), *p;
+ boolean thruption = gc_dispatcher.thruption;
if (gc_dispatcher.th_stw_initiator != self) {
odxprint(misc,"Unmapper %p self %p",gc_dispatcher.th_stw_initiator,self);
gc_assert (gc_dispatcher.th_subgc == self);
if (!--gc_dispatcher.stopped) {
for_each_thread(p) {
- {
+ if (!thruption) {
SetTlSymbolValue(STOP_FOR_GC_PENDING,NIL,p);
SetTlSymbolValue(GC_PENDING,NIL,p);
}
- set_thread_csp_access(p,1);
+ if (
+#ifdef LISP_FEATURE_SB_THRUPTION
+ SymbolTlValue(THRUPTION_PENDING,p)!=T
+#else
+ 1 /* trivially no thruption pending */
+#endif
+ || SymbolTlValue(INTERRUPTS_ENABLED,p)!=T)
+ set_thread_csp_access(p,1);
}
pthread_mutex_unlock(&all_threads_lock);
/* Release everyone */
return;
}
if ((SymbolTlValue(GC_PENDING,self)!=NIL) &&
- maybe_become_stw_initiator() && !in_race_p()) {
+ maybe_become_stw_initiator(0) && !in_race_p()) {
gc_stop_the_world();
set_thread_csp_access(self,1);
check_pending_gc(ctxptr);
set_thread_csp_access(self,1);
WITH_GC_AT_SAFEPOINTS_ONLY() {
pthread_mutex_unlock(&gc_dispatcher.mx_gcing);
+#ifdef LISP_FEATURE_SB_THRUPTION
+ while (check_pending_thruptions(ctxptr))
+ ;
+#endif
}
return;
}
}
}
+#ifdef LISP_FEATURE_SB_THRUPTION
+ while(check_pending_thruptions(ctxptr));
+#endif
}
static inline void
return; /* trivialize */
odxprint(safepoints,"edge leaving [%p]", ctxptr);
if (SymbolTlValue(GC_INHIBIT,self)!=T) {
+#ifdef LISP_FEATURE_SB_THRUPTION
+ if (SymbolTlValue(THRUPTION_PENDING,self)==T &&
+ SymbolTlValue(INTERRUPTS_ENABLED,self)==T) {
+ pthread_mutex_lock(&gc_dispatcher.mx_gcing);
+ set_thread_csp_access(self,1);
+ WITH_GC_AT_SAFEPOINTS_ONLY() {
+ pthread_mutex_unlock(&gc_dispatcher.mx_gcing);
+ while (check_pending_thruptions(ctxptr))
+ ;
+ }
+ } else
+#endif
{
pthread_mutex_lock(&gc_dispatcher.mx_gcing);
odxprint(safepoints,"edge leaving [%p] took gcing", ctxptr);
} else {
/* Entering. */
odxprint(safepoints,"edge entering [%p]", ctxptr);
+#ifdef LISP_FEATURE_SB_THRUPTION
+ while(check_pending_thruptions(ctxptr))
+ ;
+#endif
if (os_get_csp(self))
lose("thread_edge: would lose csp");
set_csp_from_context(self, ctxptr);
gc_assert(SymbolTlValue(GC_INHIBIT,self)!=T);
/* unmap GC page, signal other threads... */
- maybe_become_stw_initiator();
+ maybe_become_stw_initiator(0);
}
\f
+#ifdef LISP_FEATURE_SB_THRUPTION
+/* wake_thread(thread) -- ensure a thruption delivery to
+ * `thread'. */
+
+int
+wake_thread_posix(os_thread_t os_thread)
+{
+ int found = 0;
+ struct thread *thread;
+ struct thread *self = arch_os_get_current_thread();
+
+ /* Must not and need not attempt to signal ourselves while we're the
+ * STW initiator. */
+ if (self->os_thread == os_thread) {
+ SetTlSymbolValue(THRUPTION_PENDING,T,self);
+ WITH_GC_AT_SAFEPOINTS_ONLY()
+ while (check_pending_thruptions(0 /* ignore the sigmask */))
+ ;
+ return 0;
+ }
+
+ /* We are not in a signal handler here, so need to block signals
+ * manually. */
+ sigset_t oldset;
+ block_deferrable_signals(0, &oldset);
+
+ if (!maybe_become_stw_initiator(1) || in_race_p()) {
+ /* we are not able to wake the thread up, but the STW initiator
+ * will take care of it (kludge: unless it is in foreign code).
+ * Let's at least try to get our return value right. */
+ pthread_mutex_lock(&all_threads_lock);
+ for_each_thread (thread)
+ if (thread->os_thread == os_thread) {
+ found = 1;
+ break;
+ }
+ pthread_mutex_unlock(&all_threads_lock);
+ goto cleanup;
+ }
+ gc_stop_the_world();
+
+ /* we hold the all_threads lock */
+ for_each_thread (thread)
+ if (thread->os_thread == os_thread) {
+ /* it's still alive... */
+ found = 1;
+
+ SetTlSymbolValue(THRUPTION_PENDING,T,thread);
+ if (SymbolTlValue(GC_PENDING,thread) == T
+ || SymbolTlValue(STOP_FOR_GC_PENDING,thread) == T)
+ break;
+
+ if (os_get_csp(thread)) {
+ /* ... and in foreign code. Push it into a safety
+ * transition. */
+ int status = pthread_kill(os_thread, SIGPIPE);
+ if (status)
+ lose("wake_thread_posix: pthread_kill failed with %d\n",
+ status);
+ }
+ break;
+ }
+
+ /* If it was alive but in Lisp, the pit stop takes care of thruptions. */
+ gc_start_the_world();
+
+cleanup:
+ pthread_sigmask(SIG_SETMASK, &oldset, 0);
+ return found ? 0 : -1;
+}
+#endif /* LISP_FEATURE_SB_THRUPTION */
+
void
thread_in_safety_transition(os_context_t *ctx)
{
thread_pitstop(ctx);
}
+void
+thread_interrupted(os_context_t *ctx)
+{
+ FSHOW_SIGNAL((stderr, "thread_interrupted\n"));
+ thread_pitstop(ctx);
+}
+
void**
os_get_csp(struct thread* th)
{
#ifndef LISP_FEATURE_WIN32
+# ifdef LISP_FEATURE_SB_THRUPTION
+void
+thruption_handler(int signal, siginfo_t *info, os_context_t *ctx)
+{
+ struct thread *self = arch_os_get_current_thread();
+
+ if (!os_get_csp(self))
+ /* In Lisp code. Do not run thruptions asynchronously. The
+ * next safepoint will take care of it. */
+ return;
+
+ /* In C code. As a rule, we assume that running thruptions is OK. */
+ fake_foreign_function_call(ctx);
+ thread_in_safety_transition(ctx);
+ undo_fake_foreign_function_call(ctx);
+}
+# endif
+
/* Designed to be of the same type as call_into_lisp. Ignores its
* arguments. */
lispobj
projects / sbcl.git / blobdiff