erts: Implement erl_halt

6 files changed, 160 insertions, 28 deletions

diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 717315d8bd..d866a1fe3f 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1997-2011. All Rights Reserved.
+ * Copyright Ericsson AB 1997-2012. All Rights Reserved.
  *
  * The contents of this file are subject to the Erlang Public License,
  * Version 1.1, (the "License"); you may not use this file except in
@@ -1510,7 +1510,7 @@ __decl_noreturn void erts_thr_fatal_error(int err, char *what)
 #endif
 
 static void
-system_cleanup(int exit_code)
+system_cleanup(int flush_async)
 {
     /*
      * Make sure only one thread exits the runtime system.
@@ -1542,7 +1542,7 @@ system_cleanup(int exit_code)
      *    (in threaded non smp case).
      */
 
-    if (exit_code != 0
+    if (!flush_async
 	|| !erts_initialized
 #if defined(USE_THREADS) && !defined(ERTS_SMP)
 	|| !erts_equal_tids(main_thread, erts_thr_self())
@@ -1632,14 +1632,12 @@ __decl_noreturn void erl_exit0(char *file, int line, int n, char *fmt,...)
     exit(an);
 }
 
-__decl_noreturn void erl_exit(int n, char *fmt,...)
+static __decl_noreturn void __noreturn
+erl_exit_vv(int n, int flush_async, char *fmt, va_list args1, va_list args2)
 {
     unsigned int an;
-    va_list args;
 
-    va_start(args, fmt);
-
-    system_cleanup(n);
+    system_cleanup(flush_async);
 
     save_statistics();
 
@@ -1649,18 +1647,13 @@ __decl_noreturn void erl_exit(int n, char *fmt,...)
 	erts_mtrace_exit((Uint32) an);
 
     /* Produce an Erlang core dump if error */
-    if (n > 0 && erts_initialized &&
-	(erts_no_crash_dump == 0 || n == ERTS_DUMP_EXIT)) {
-	erl_crash_dump_v((char*) NULL, 0, fmt, args);
+    if (((n > 0 && erts_no_crash_dump == 0) || n == ERTS_DUMP_EXIT)
+	&& erts_initialized) {
+	erl_crash_dump_v((char*) NULL, 0, fmt, args1);
     }
 
-    /* need to reinitialize va_args thing */
-    va_end(args);
-    va_start(args, fmt);
-
     if (fmt != NULL && *fmt != '\0')
-	  erl_error(fmt, args);	/* Print error message. */
-    va_end(args);
+	  erl_error(fmt, args2);	/* Print error message. */
     sys_tty_reset(n);
 
     if (n == ERTS_INTR_EXIT)
@@ -1672,3 +1665,24 @@ __decl_noreturn void erl_exit(int n, char *fmt,...)
     exit(an);
 }
 
+/* Exit without flushing async threads */
+__decl_noreturn void __noreturn erl_exit(int n, char *fmt, ...)
+{
+    va_list args1, args2;
+    va_start(args1, fmt);
+    va_start(args2, fmt);
+    erl_exit_vv(n, 0, fmt, args1, args2);
+    va_end(args2);
+    va_end(args1);
+}
+
+/* Exit after flushing async threads */
+__decl_noreturn void __noreturn erl_exit_flush_async(int n, char *fmt, ...)
+{
+    va_list args1, args2;
+    va_start(args1, fmt);
+    va_start(args2, fmt);
+    erl_exit_vv(n, 1, fmt, args1, args2);
+    va_end(args2);
+    va_end(args1);
+}
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 138acfeb2c..45f6dc800c 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -104,6 +104,9 @@ do {								\
 #define ERTS_EMPTY_RUNQ(RQ) \
   ((RQ)->len == 0 && (RQ)->misc.start == NULL)
 
+#define ERTS_EMPTY_RUNQ_PORTS(RQ) \
+  ((RQ)->ports.info.len == 0 && (RQ)->misc.start == NULL)
+
 extern BeamInstr beam_apply[];
 extern BeamInstr beam_exit[];
 extern BeamInstr beam_continue_exit[];
@@ -366,6 +369,9 @@ dbg_chk_aux_work_val(erts_aint32_t value)
 #ifdef ERTS_SMP_SCHEDULERS_NEED_TO_CHECK_CHILDREN
     valid |= ERTS_SSI_AUX_WORK_CHECK_CHILDREN;
 #endif
+#ifdef ERTS_SSI_AUX_WORK_REAP_PORTS
+    valid |= ERTS_SSI_AUX_WORK_REAP_PORTS;
+#endif
 
     if (~valid & value)
 	erl_exit(ERTS_ABORT_EXIT,
@@ -861,8 +867,6 @@ set_aux_work_flags_wakeup_nob(ErtsSchedulerSleepInfo *ssi,
     }
 }
 
-#if 0 /* Currently not used */
-
 static ERTS_INLINE void
 set_aux_work_flags_wakeup_relb(ErtsSchedulerSleepInfo *ssi,
 			       erts_aint32_t flgs)
@@ -882,8 +886,6 @@ set_aux_work_flags_wakeup_relb(ErtsSchedulerSleepInfo *ssi,
     }
 }
 
-#endif
-
 static ERTS_INLINE erts_aint32_t
 set_aux_work_flags(ErtsSchedulerSleepInfo *ssi, erts_aint32_t flgs)
 {
@@ -1351,6 +1353,65 @@ handle_check_children(ErtsAuxWorkData *awdp, erts_aint32_t aux_work)
 
 #endif
 
+static void
+notify_reap_ports_relb(void)
+{
+    int i;
+    for (i = 0; i < erts_no_schedulers; i++) {
+	set_aux_work_flags_wakeup_relb(ERTS_SCHED_SLEEP_INFO_IX(i),
+				       ERTS_SSI_AUX_WORK_REAP_PORTS);
+    }
+}
+
+erts_smp_atomic32_t erts_halt_progress;
+int erts_halt_code;
+
+static ERTS_INLINE erts_aint32_t
+handle_reap_ports(ErtsAuxWorkData *awdp, erts_aint32_t aux_work)
+{
+    unset_aux_work_flags(awdp->ssi, ERTS_SSI_AUX_WORK_REAP_PORTS);
+    awdp->esdp->run_queue->halt_in_progress = 1;
+    if (erts_smp_atomic32_dec_read_acqb(&erts_halt_progress) == 0) {
+	int i;
+	erts_smp_atomic32_set_nob(&erts_halt_progress, 1);
+	for (i = 0; i < erts_max_ports; i++) {
+	    Port *prt = &erts_port[i];
+	    erts_smp_port_state_lock(prt);
+	    if ((prt->status & (ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP
+				| ERTS_PORT_SFLG_HALT))) {
+		erts_smp_port_state_unlock(prt);
+		continue;
+	    }
+	    /* We need to set the halt flag - get the port lock */
+#ifdef ERTS_SMP
+	    erts_smp_atomic_inc_nob(&prt->refc);
+#endif
+	    erts_smp_port_state_unlock(prt);
+#ifdef ERTS_SMP
+	    erts_smp_mtx_lock(prt->lock);
+#endif
+	    if ((prt->status & (ERTS_PORT_SFLGS_INVALID_DRIVER_LOOKUP
+				| ERTS_PORT_SFLG_HALT))) {
+		erts_port_release(prt);
+		continue;
+	    }
+	    erts_port_status_bor_set(prt, ERTS_PORT_SFLG_HALT);
+	    erts_smp_atomic32_inc_nob(&erts_halt_progress);
+	    if (prt->status & (ERTS_PORT_SFLG_EXITING
+			       | ERTS_PORT_SFLG_CLOSING)) {
+		erts_port_release(prt);
+		continue;
+	    }
+	    erts_do_exit_port(prt, prt->id, am_killed);
+	    erts_port_release(prt);
+	}
+	if (erts_smp_atomic32_dec_read_nob(&erts_halt_progress) == 0) {
+	    erl_exit_flush_async(erts_halt_code, "");
+	}
+    }
+    return aux_work & ~ERTS_SSI_AUX_WORK_REAP_PORTS;
+}
+
 #if HAVE_ERTS_MSEG
 
 static ERTS_INLINE erts_aint32_t
@@ -1451,6 +1512,9 @@ handle_aux_work(ErtsAuxWorkData *awdp, erts_aint32_t orig_aux_work)
 		    handle_mseg_cache_check);
 #endif
 
+    HANDLE_AUX_WORK(ERTS_SSI_AUX_WORK_REAP_PORTS,
+		    handle_reap_ports);
+
     ERTS_DBG_CHK_AUX_WORK_VAL(aux_work);
 
     return aux_work;
@@ -2716,6 +2780,9 @@ try_steal_task_from_victim(ErtsRunQueue *rq, int *rq_lockedp, ErtsRunQueue *vrq)
     ERTS_SMP_LC_CHK_RUNQ_LOCK(rq, *rq_lockedp);
     ERTS_SMP_LC_CHK_RUNQ_LOCK(vrq, vrq_locked);
 
+    if (rq->halt_in_progress)
+	goto try_steal_port;
+
     /*
      * Check for a runnable process to steal...
      */
@@ -2802,6 +2869,8 @@ try_steal_task_from_victim(ErtsRunQueue *rq, int *rq_lockedp, ErtsRunQueue *vrq)
 	vrq_locked = 1;
     }
 
+ try_steal_port:
+
     ERTS_SMP_LC_CHK_RUNQ_LOCK(rq, *rq_lockedp);
     ERTS_SMP_LC_CHK_RUNQ_LOCK(vrq, vrq_locked);
 
@@ -2917,7 +2986,8 @@ try_steal_task(ErtsRunQueue *rq)
 	erts_smp_runq_lock(rq);
 
     if (!res)
-	res = !ERTS_EMPTY_RUNQ(rq);
+	res = rq->halt_in_progress ?
+	    !ERTS_EMPTY_RUNQ_PORTS(rq) : !ERTS_EMPTY_RUNQ(rq);
 
     return res;
 }
@@ -3583,6 +3653,7 @@ erts_init_scheduling(int no_schedulers, int no_schedulers_online)
 	rq->len = 0;
 	rq->wakeup_other = 0;
 	rq->wakeup_other_reds = 0;
+	rq->halt_in_progress = 0;
 
 	rq->procs.len = 0;
 	rq->procs.pending_exiters = NULL;
@@ -3777,6 +3848,9 @@ erts_init_scheduling(int no_schedulers, int no_schedulers_online)
     ERTS_VERIFY_UNUSED_TEMP_ALLOC(NULL);
 #endif
 #endif
+
+    erts_smp_atomic32_init_relb(&erts_halt_progress, -1);
+    erts_halt_code = 0;
 }
 
 ErtsRunQueue *
@@ -6343,7 +6417,9 @@ Process *schedule(Process *p, int calls)
 
 	ASSERT(rq->len == rq->procs.len + rq->ports.info.len);
 
-	if (rq->len == 0 && !rq->misc.start) {
+	if ((rq->len == 0 && !rq->misc.start)
+	    || (rq->halt_in_progress
+		&& rq->ports.info.len == 0 && !rq->misc.start)) {
 
 #ifdef ERTS_SMP
 
@@ -6441,7 +6517,8 @@ Process *schedule(Process *p, int calls)
 	if (rq->ports.info.len) {
 	    int have_outstanding_io;
 	    have_outstanding_io = erts_port_task_execute(rq, &esdp->current_port);
-	    if (have_outstanding_io && fcalls > 2*input_reductions) {
+	    if ((have_outstanding_io && fcalls > 2*input_reductions)
+		|| rq->halt_in_progress) {
 		/*
 		 * If we have performed more than 2*INPUT_REDUCTIONS since
 		 * last call to erl_sys_schedule() and we still haven't
@@ -9867,3 +9944,30 @@ debug_processes_assert_error(char* expr, char* file, int line)
 /*                                                                           *\
  * End of the processes/0 BIF implementation.                                *
 \* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * A nice system halt closing all open port goes as follows:
+ * 1) This function schedules the aux work ERTS_SSI_AUX_WORK_REAP_PORTS
+ *    on all schedulers, then schedules itself out.
+ * 2) All shedulers detect this and set the flag halt_in_progress
+ *    on their run queue. The last scheduler sets all non-closed ports
+ *    ERTS_PORT_SFLG_HALT. Global atomic erts_halt_progress is used
+ *    as refcount to determine which is last.
+ * 3) While the run ques has flag halt_in_progress no processes
+ *    will be scheduled, only ports.
+ * 4) When the last port closes that scheduler calls erlang:halt/1.
+ *    The same global atomic is used as refcount.
+ *
+ * A BIF that calls this should make sure to schedule out to never come back:
+ *    erl_halt((int)(- code));
+ *    ERTS_BIF_YIELD1(bif_export[BIF_erlang_halt_1], BIF_P, NIL);
+ */
+void erl_halt(int code)
+{
+    if (-1 == erts_smp_atomic32_cmpxchg_acqb(&erts_halt_progress,
+					     erts_no_schedulers,
+					     -1)) {
+	erts_halt_code = code;
+	notify_reap_ports_relb();
+    }
+}
diff --git a/erts/emulator/beam/erl_process.h b/erts/emulator/beam/erl_process.h
index c23810f15a..d671638ce8 100644
--- a/erts/emulator/beam/erl_process.h
+++ b/erts/emulator/beam/erl_process.h
@@ -264,6 +264,7 @@ typedef enum {
 #define ERTS_SSI_AUX_WORK_CHECK_CHILDREN	(((erts_aint32_t) 1) << 8)
 #define ERTS_SSI_AUX_WORK_SET_TMO		(((erts_aint32_t) 1) << 9)
 #define ERTS_SSI_AUX_WORK_MSEG_CACHE_CHECK	(((erts_aint32_t) 1) << 10)
+#define ERTS_SSI_AUX_WORK_REAP_PORTS		(((erts_aint32_t) 1) << 11)
 
 typedef struct ErtsSchedulerSleepInfo_ ErtsSchedulerSleepInfo;
 
@@ -341,6 +342,7 @@ struct ErtsRunQueue_ {
     int len;
     int wakeup_other;
     int wakeup_other_reds;
+    int halt_in_progress;
 
     struct {
 	int len;
@@ -1659,4 +1661,6 @@ erts_sched_poke(ErtsSchedulerSleepInfo *ssi)
 #endif
 
 
-
+void erl_halt(int code);
+extern erts_smp_atomic32_t erts_halt_progress;
+extern int erts_halt_code;
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index f1335f600d..34eb984925 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2011. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2012. All Rights Reserved.
  *
  * The contents of this file are subject to the Erlang Public License,
  * Version 1.1, (the "License"); you may not use this file except in
@@ -806,6 +806,8 @@ do {									\
 /* Port uses port specific locking (opposed to driver specific locking) */
 #define ERTS_PORT_SFLG_PORT_SPECIFIC_LOCK ((Uint32) (1 << 13))
 #define ERTS_PORT_SFLG_INVALID		((Uint32) (1 << 14))
+/* Last port to terminate halts the emulator */
+#define ERTS_PORT_SFLG_HALT		((Uint32) (1 << 15))
 #ifdef DEBUG
 /* Only debug: make sure all flags aren't cleared unintentionally */
 #define ERTS_PORT_SFLG_PORT_DEBUG	((Uint32) (1 << 31))
@@ -900,6 +902,7 @@ void loaded(int, void *);
 
 __decl_noreturn void __noreturn erl_exit(int n, char*, ...);
 __decl_noreturn void __noreturn erl_exit0(char *, int, int n, char*, ...);
+__decl_noreturn void __noreturn erl_exit_flush_async(int n, char*, ...);
 void erl_error(char*, va_list);
 
 #define ERL_EXIT0(n,f)		erl_exit0(__FILE__, __LINE__, n, f)
diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
index b23b1f628d..591eb834e6 100644
--- a/erts/emulator/beam/io.c
+++ b/erts/emulator/beam/io.c
@@ -1837,6 +1837,7 @@ terminate_port(Port *prt)
     Eterm send_closed_port_id;
     Eterm connected_id = NIL /* Initialize to silence compiler */;
     erts_driver_t *drv;
+    int halt;
 
     ERTS_SMP_CHK_NO_PROC_LOCKS;
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(prt));
@@ -1844,6 +1845,8 @@ terminate_port(Port *prt)
     ASSERT(!prt->nlinks);
     ASSERT(!prt->monitors);
 
+    /* prt->status may be altered by kill_port()below */
+    halt = (prt->status & ERTS_PORT_SFLG_HALT) != 0;
     if (prt->status & ERTS_PORT_SFLG_SEND_CLOSED) {
 	erts_port_status_band_set(prt, ~ERTS_PORT_SFLG_SEND_CLOSED);
 	send_closed_port_id = prt->id;
@@ -1895,6 +1898,10 @@ terminate_port(Port *prt)
      * We don't want to send the closed message until after the
      * port has been removed from the port table (in kill_port()).
      */
+    if (halt && (erts_smp_atomic32_dec_read_nob(&erts_halt_progress) == 0)) {
+	erts_smp_port_unlock(prt); /* We will exit and never return */
+	erl_exit_flush_async(erts_halt_code, "");
+    }
     if (is_internal_port(send_closed_port_id))
 	deliver_result(send_closed_port_id, connected_id, am_closed);
 
diff --git a/erts/emulator/beam/sys.h b/erts/emulator/beam/sys.h
index eb6f2f8516..7b2bb81f62 100644
--- a/erts/emulator/beam/sys.h
+++ b/erts/emulator/beam/sys.h
@@ -1,7 +1,7 @@
 /*
  * %CopyrightBegin%
  *
- * Copyright Ericsson AB 1996-2011. All Rights Reserved.
+ * Copyright Ericsson AB 1996-2012. All Rights Reserved.
  *
  * The contents of this file are subject to the Erlang Public License,
  * Version 1.1, (the "License"); you may not use this file except in
@@ -511,7 +511,7 @@ __decl_noreturn void __noreturn erl_exit(int n, char*, ...);
 /* Some special erl_exit() codes: */
 #define ERTS_INTR_EXIT	INT_MIN		/* called from signal handler */
 #define ERTS_ABORT_EXIT	(INT_MIN + 1)	/* no crash dump; only abort() */
-#define ERTS_DUMP_EXIT	(127)		/* crash dump; then exit() */
+#define ERTS_DUMP_EXIT	(INT_MIN + 2)	/* crash dump; then exit() */
 
 Eterm erts_check_io_info(void *p);