erts: Yield later during process exit and allow free procs to run

OTP-15610

5 files changed, 375 insertions, 272 deletions

diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index 4ef06464f4..90162a6543 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -885,19 +885,22 @@ void process_main(Eterm * x_reg_array, FloatDef* f_reg_array)
 #include "beam_warm.h"
 
  OpCase(normal_exit): {
-     SWAPOUT;
+     HEAVY_SWAPOUT;
      c_p->freason = EXC_NORMAL;
      c_p->arity = 0; /* In case this process will ever be garbed again. */
      ERTS_UNREQ_PROC_MAIN_LOCK(c_p);
      erts_do_exit_process(c_p, am_normal);
      ERTS_REQ_PROC_MAIN_LOCK(c_p);
+     HEAVY_SWAPIN;
      goto do_schedule;
  }
 
  OpCase(continue_exit): {
+     HEAVY_SWAPOUT;
      ERTS_UNREQ_PROC_MAIN_LOCK(c_p);
      erts_continue_exit_process(c_p);
      ERTS_REQ_PROC_MAIN_LOCK(c_p);
+     HEAVY_SWAPIN;
      goto do_schedule;
  }
 
diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index 08dcc5ea9a..31f19d1b88 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -275,6 +275,7 @@ type	ML_DIST		STANDARD	SYSTEM		monitor_link_dist
 type	PF3_ARGS	SHORT_LIVED	PROCESSES	process_flag_3_arguments
 type	SETUP_CONN_ARG	SHORT_LIVED	PROCESSES	setup_connection_argument
 type    LIST_TRAP       SHORT_LIVED     PROCESSES       list_bif_trap_state
+type    CONT_EXIT_TRAP  SHORT_LIVED     PROCESSES       continue_exit_trap_state
 
 type	ENVIRONMENT	SYSTEM		SYSTEM		environment
 
diff --git a/erts/emulator/beam/erl_db.c b/erts/emulator/beam/erl_db.c
index 0d570517ec..4132a54934 100644
--- a/erts/emulator/beam/erl_db.c
+++ b/erts/emulator/beam/erl_db.c
@@ -3701,7 +3701,7 @@ static SWord proc_cleanup_fixed_table(Process* p, DbFixation* fix)
 /*
  * erts_db_process_exiting() is called when a process terminates.
  * It returns 0 when completely done, and !0 when it wants to
- * yield. c_p->u.terminate can hold a pointer to a state while
+ * yield. *yield_state can hold a pointer to a state while
  * yielding.
  */
 #define ERTS_DB_INTERNAL_ERROR(LSTR) \
@@ -3709,7 +3709,7 @@ static SWord proc_cleanup_fixed_table(Process* p, DbFixation* fix)
 	   __FILE__, __LINE__)
 
 int
-erts_db_process_exiting(Process *c_p, ErtsProcLocks c_p_locks)
+erts_db_process_exiting(Process *c_p, ErtsProcLocks c_p_locks, void **yield_state)
 {
     typedef struct {
         enum {
@@ -3719,7 +3719,7 @@ erts_db_process_exiting(Process *c_p, ErtsProcLocks c_p_locks)
         }op;
         DbTable *tb;
     } CleanupState;
-    CleanupState *state = (CleanupState *) c_p->u.terminate;
+    CleanupState *state = (CleanupState *) *yield_state;
     Eterm pid = c_p->common.id;
     CleanupState default_state;
     SWord initial_reds = ERTS_BIF_REDS_LEFT(c_p);
@@ -3792,7 +3792,7 @@ erts_db_process_exiting(Process *c_p, ErtsProcLocks c_p_locks)
 
                 if (state != &default_state)
                     erts_free(ERTS_ALC_T_DB_PROC_CLEANUP, state);
-                c_p->u.terminate = NULL;
+                *yield_state = NULL;
 
                 BUMP_REDS(c_p, (initial_reds - reds));
                 return 0;
@@ -3812,12 +3812,12 @@ erts_db_process_exiting(Process *c_p, ErtsProcLocks c_p_locks)
  yield:
 
     if (state == &default_state) {
-	c_p->u.terminate = erts_alloc(ERTS_ALC_T_DB_PROC_CLEANUP,
-				      sizeof(CleanupState));
-	sys_memcpy(c_p->u.terminate, (void*) state, sizeof(CleanupState));
+	*yield_state = erts_alloc(ERTS_ALC_T_DB_PROC_CLEANUP,
+                                  sizeof(CleanupState));
+	sys_memcpy(*yield_state, (void*) state, sizeof(CleanupState));
     }
     else
-        ASSERT(state == c_p->u.terminate);
+        ASSERT(state == *yield_state);
 
     return !0;
 }
diff --git a/erts/emulator/beam/erl_db.h b/erts/emulator/beam/erl_db.h
index 5955d42aae..dc77fbb60c 100644
--- a/erts/emulator/beam/erl_db.h
+++ b/erts/emulator/beam/erl_db.h
@@ -111,7 +111,7 @@ typedef enum {
 } ErtsDbSpinCount;
 
 void init_db(ErtsDbSpinCount);
-int erts_db_process_exiting(Process *, ErtsProcLocks);
+int erts_db_process_exiting(Process *, ErtsProcLocks, void **);
 int erts_db_execute_free_fixation(Process*, DbFixation*);
 void db_info(fmtfn_t, void *, int);
 void erts_db_foreach_table(void (*)(DbTable *, void *), void *);
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index f9cc85b6d7..66af9574b8 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -735,12 +735,6 @@ erts_pre_init_process(void)
 #endif
 }
 
-static void
-release_process(void *vproc)
-{
-    erts_proc_dec_refc((Process *) vproc);
-}
-
 /* initialize the scheduler */
 void
 erts_init_process(int ncpu, int proc_tab_size, int legacy_proc_tab)
@@ -752,7 +746,7 @@ erts_init_process(int ncpu, int proc_tab_size, int legacy_proc_tab)
 
     erts_ptab_init_table(&erts_proc,
 			 ERTS_ALC_T_PROC_TABLE,
-			 release_process,
+			 NULL,
 			 (ErtsPTabElementCommon *) &erts_invalid_process.common,
 			 proc_tab_size,
 			 sizeof(Process),
@@ -6519,8 +6513,7 @@ schedule_out_process(ErtsRunQueue *c_rq, erts_aint32_t state, Process *p,
 
 	n &= ~running_flgs;
 	if ((!!(a & (ERTS_PSFLG_ACTIVE_SYS|ERTS_PSFLG_DIRTY_ACTIVE_SYS))
-	    | ((a & (ERTS_PSFLG_ACTIVE|ERTS_PSFLG_SUSPENDED)) == ERTS_PSFLG_ACTIVE))
-            & !(a & ERTS_PSFLG_FREE)) {
+	    | ((a & (ERTS_PSFLG_ACTIVE|ERTS_PSFLG_SUSPENDED)) == ERTS_PSFLG_ACTIVE))) {
 	    enqueue = check_enqueue_in_prio_queue(p, &enq_prio, &n, a);
 	}
 	a = erts_atomic32_cmpxchg_mb(&p->state, n, e);
@@ -6555,7 +6548,6 @@ schedule_out_process(ErtsRunQueue *c_rq, erts_aint32_t state, Process *p,
     else {
 	Process* sched_p;
 
-        ASSERT(!(n & ERTS_PSFLG_FREE));
 	ASSERT(!(n & ERTS_PSFLG_SUSPENDED) || (n & (ERTS_PSFLG_ACTIVE_SYS
 						    | ERTS_PSFLG_DIRTY_ACTIVE_SYS)));
 
@@ -6685,8 +6677,8 @@ change_proc_schedule_state(Process *p,
 
 	enqueue = ERTS_ENQUEUE_NOT;
 
-	if (a & ERTS_PSFLG_FREE)
-	    break; /* We don't want to schedule free processes... */
+        if ((a & (ERTS_PSFLG_FREE|ERTS_PSFLG_ACTIVE)) == ERTS_PSFLG_FREE)
+            break; /* If free and not active, do not schedule */
 
 	if (clear_state_flags)
 	    n &= ~clear_state_flags;
@@ -8131,7 +8123,8 @@ done:
 ErtsSchedSuspendResult
 erts_block_multi_scheduling(Process *p, ErtsProcLocks plocks, int on, int normal, int all)
 {
-    int resume_proc, ix, res, have_unlocked_plocks = 0;
+    ErtsSchedSuspendResult res;
+    int resume_proc, ix, have_unlocked_plocks = 0;
     ErtsProcList *plp;
     ErtsMultiSchedulingBlock *msbp;
     erts_aint32_t chng_flg;
@@ -9629,7 +9622,8 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
 
 	    while (1) {
 		erts_aint32_t exp, new;
-		int run_process;
+		int run_process, not_running, exiting_on_normal_sched,
+                    not_suspended, not_exiting_on_dirty_sched;
 		new = exp = state;
 		new &= psflg_band_mask;
 		/*
@@ -9638,29 +9632,33 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
 		 * scheduler, and not suspended (and not in a
 		 * state where suspend should be ignored).
 		 */
-		run_process = (((!(state & (ERTS_PSFLG_RUNNING
-					    | ERTS_PSFLG_RUNNING_SYS
-					    | ERTS_PSFLG_DIRTY_RUNNING
-					    | ERTS_PSFLG_DIRTY_RUNNING_SYS
-					    | ERTS_PSFLG_FREE)))
-				| (((state & (ERTS_PSFLG_RUNNING
-
-					      | ERTS_PSFLG_FREE
-					      | ERTS_PSFLG_RUNNING_SYS
-					      | ERTS_PSFLG_DIRTY_RUNNING_SYS
-					      | ERTS_PSFLG_EXITING))
-				    == ERTS_PSFLG_EXITING)
-				   & (!!is_normal_sched))
-				   )
-			       & ((state & (ERTS_PSFLG_SUSPENDED
-					    | ERTS_PSFLG_EXITING
-					    | ERTS_PSFLG_FREE
-					    | ERTS_PSFLG_ACTIVE_SYS
-					    | ERTS_PSFLG_DIRTY_ACTIVE_SYS))
-				  != ERTS_PSFLG_SUSPENDED)
-                               & (!(state & ERTS_PSFLG_EXITING)
-                                  | (!!is_normal_sched))
-                    );
+                not_running = !(state & (ERTS_PSFLG_RUNNING
+                                         | ERTS_PSFLG_RUNNING_SYS
+                                         | ERTS_PSFLG_DIRTY_RUNNING
+                                         | ERTS_PSFLG_DIRTY_RUNNING_SYS
+                                         | ERTS_PSFLG_FREE));
+                exiting_on_normal_sched =
+                    ((state & (ERTS_PSFLG_RUNNING
+                               | ERTS_PSFLG_ACTIVE
+                               | ERTS_PSFLG_RUNNING_SYS
+                               | ERTS_PSFLG_DIRTY_RUNNING_SYS
+                               | ERTS_PSFLG_EXITING))
+                     == (ERTS_PSFLG_EXITING|ERTS_PSFLG_ACTIVE))
+                    & (!!is_normal_sched);
+
+
+                not_suspended = ((state & (ERTS_PSFLG_SUSPENDED
+                                           | ERTS_PSFLG_EXITING
+                                           | ERTS_PSFLG_FREE
+                                           | ERTS_PSFLG_ACTIVE_SYS
+                                           | ERTS_PSFLG_DIRTY_ACTIVE_SYS))
+                                 != ERTS_PSFLG_SUSPENDED);
+
+                not_exiting_on_dirty_sched = !(state & ERTS_PSFLG_EXITING) | (!!is_normal_sched);
+
+		run_process = (not_running | exiting_on_normal_sched)
+                    & not_suspended
+                    & not_exiting_on_dirty_sched;
 
 		if (run_process) {
 		    if (state & (ERTS_PSFLG_ACTIVE_SYS
@@ -9951,7 +9949,7 @@ trace_schedule_in(Process *p, erts_aint32_t state)
     /* Clear tracer if it has been removed */
     if (erts_is_tracer_proc_enabled(p, ERTS_PROC_LOCK_MAIN, &p->common)) {
 
-        if (state & ERTS_PSFLG_EXITING) {
+        if (state & ERTS_PSFLG_EXITING && p->u.terminate) {
             if (ARE_TRACE_FLAGS_ON(p, F_TRACE_SCHED_EXIT))
                 trace_sched(p, ERTS_PROC_LOCK_MAIN, am_in_exiting);
         }
@@ -9975,12 +9973,9 @@ trace_schedule_out(Process *p, erts_aint32_t state)
     if (IS_TRACED_FL(p, F_TRACE_CALLS) && !(state & ERTS_PSFLG_FREE))
         erts_schedule_time_break(p, ERTS_BP_CALL_TIME_SCHEDULE_OUT);
 
-    if ((state & (ERTS_PSFLG_FREE|ERTS_PSFLG_EXITING)) == ERTS_PSFLG_EXITING) {
+    if (state & ERTS_PSFLG_EXITING && p->u.terminate) {
         if (ARE_TRACE_FLAGS_ON(p, F_TRACE_SCHED_EXIT))
-            trace_sched(p, ERTS_PROC_LOCK_MAIN,
-                        ((state & ERTS_PSFLG_FREE)
-                         ? am_out_exited
-                         : am_out_exiting));
+            trace_sched(p, ERTS_PROC_LOCK_MAIN, am_out_exiting);
     }
     else {
         if (ARE_TRACE_FLAGS_ON(p, F_TRACE_SCHED) ||
@@ -12323,11 +12318,8 @@ erts_do_exit_process(Process* p, Eterm reason)
 
     set_self_exiting(p, reason, NULL, NULL, NULL);
 
-    if (IS_TRACED(p)) {
-	if (IS_TRACED_FL(p, F_TRACE_CALLS))
-	    erts_schedule_time_break(p, ERTS_BP_CALL_TIME_SCHEDULE_EXITING);
-
-    }
+    if (IS_TRACED_FL(p, F_TRACE_CALLS))
+        erts_schedule_time_break(p, ERTS_BP_CALL_TIME_SCHEDULE_EXITING);
 
     erts_trace_check_exiting(p->common.id);
 
@@ -12342,288 +12334,378 @@ erts_do_exit_process(Process* p, Eterm reason)
 
     erts_proc_unlock(p, ERTS_PROC_LOCKS_ALL_MINOR);
 
-    if (IS_TRACED_FL(p,F_TRACE_PROCS))
+    if (IS_TRACED_FL(p, F_TRACE_PROCS))
         trace_proc(p, ERTS_PROC_LOCK_MAIN, p, am_exit, reason);
 
-
     /*
      * p->u.initial of this process can *not* be used anymore;
      * will be overwritten by misc termination data.
      */
     p->u.terminate = NULL;
 
+    BUMP_REDS(p, 100);
+
     erts_continue_exit_process(p);
 }
 
-void
-erts_continue_exit_process(Process *p)
-{
+enum continue_exit_phase {
+    ERTS_CONTINUE_EXIT_TIMERS,
+    ERTS_CONTINUE_EXIT_BLCKD_MSHED,
+    ERTS_CONTINUE_EXIT_BLCKD_NMSHED,
+    ERTS_CONTINUE_EXIT_USING_DB,
+    ERTS_CONTINUE_EXIT_CLEAN_SYS_TASKS,
+    ERTS_CONTINUE_EXIT_FREE,
+    ERTS_CONTINUE_EXIT_CLEAN_SYS_TASKS_AFTER,
+    ERTS_CONTINUE_EXIT_LINKS,
+    ERTS_CONTINUE_EXIT_MONITORS,
+    ERTS_CONTINUE_EXIT_LT_MONITORS,
+    ERTS_CONTINUE_EXIT_HANDLE_PROC_SIG,
+};
+
+struct continue_exit_state {
+    enum continue_exit_phase phase;
     ErtsLink *links;
     ErtsMonitor *monitors;
     ErtsMonitor *lt_monitors;
+    Eterm reason;
+    ErtsProcExitContext pectxt;
+    DistEntry *dep;
+    void *yield_state;
+};
+
+void
+erts_continue_exit_process(Process *p)
+{
+    struct continue_exit_state static_state, *trap_state = &static_state;
     ErtsProcLocks curr_locks = ERTS_PROC_LOCK_MAIN;
-    Eterm reason = p->fvalue;
-    DistEntry *dep = NULL;
     erts_aint32_t state;
     int delay_del_proc = 0;
-    ErtsProcExitContext pectxt;
-
+    Sint reds = ERTS_BIF_REDS_LEFT(p);
 #ifdef DEBUG
     int yield_allowed = 1;
 #endif
 
+    if (p->u.terminate) {
+        trap_state = p->u.terminate;
+    } else {
+        trap_state->phase = ERTS_CONTINUE_EXIT_TIMERS;
+        trap_state->reason = p->fvalue;
+        trap_state->dep = NULL;
+        trap_state->yield_state = NULL;
+    }
+
     ERTS_LC_ASSERT(ERTS_PROC_LOCK_MAIN == erts_proc_lc_my_proc_locks(p));
 
     ASSERT(ERTS_PROC_IS_EXITING(p));
 
     ASSERT(erts_proc_read_refc(p) > 0);
-    if (p->bif_timers) {
-	if (erts_cancel_bif_timers(p, &p->bif_timers, &p->u.terminate)) {
-	    ASSERT(erts_proc_read_refc(p) > 0);
-	    goto yield;
-	}
-	ASSERT(erts_proc_read_refc(p) > 0);
-	p->bif_timers = NULL;
-    }
-
-    if (p->flags & F_SCHDLR_ONLN_WAITQ)
-	abort_sched_onln_chng_waitq(p);
-
-    if (p->flags & F_HAVE_BLCKD_MSCHED) {
-	ErtsSchedSuspendResult ssr;
-	ssr = erts_block_multi_scheduling(p, ERTS_PROC_LOCK_MAIN, 0, 0, 1);
-	switch (ssr) {
-	case ERTS_SCHDLR_SSPND_YIELD_RESTART:
-	    goto yield;
-	case ERTS_SCHDLR_SSPND_DONE_MSCHED_BLOCKED:
-	case ERTS_SCHDLR_SSPND_DONE_NMSCHED_BLOCKED:
-	case ERTS_SCHDLR_SSPND_YIELD_DONE_MSCHED_BLOCKED:
-	case ERTS_SCHDLR_SSPND_YIELD_DONE_NMSCHED_BLOCKED:
-	case ERTS_SCHDLR_SSPND_DONE:
-	case ERTS_SCHDLR_SSPND_YIELD_DONE:
-	    p->flags &= ~F_HAVE_BLCKD_MSCHED;
-	    break;
-	case ERTS_SCHDLR_SSPND_EINVAL:
-	default:
-	    erts_exit(ERTS_ABORT_EXIT, "%s:%d: Internal error: %d\n",
-		      __FILE__, __LINE__, (int) ssr);
-	}
-    }
-    if (p->flags & F_HAVE_BLCKD_NMSCHED) {
-	ErtsSchedSuspendResult ssr;
-	ssr = erts_block_multi_scheduling(p, ERTS_PROC_LOCK_MAIN, 0, 1, 1);
-	switch (ssr) {
-	case ERTS_SCHDLR_SSPND_YIELD_RESTART:
-	    goto yield;
-	case ERTS_SCHDLR_SSPND_DONE_MSCHED_BLOCKED:
-	case ERTS_SCHDLR_SSPND_DONE_NMSCHED_BLOCKED:
-	case ERTS_SCHDLR_SSPND_YIELD_DONE_MSCHED_BLOCKED:
-	case ERTS_SCHDLR_SSPND_YIELD_DONE_NMSCHED_BLOCKED:
-	case ERTS_SCHDLR_SSPND_DONE:
-	case ERTS_SCHDLR_SSPND_YIELD_DONE:
-	    p->flags &= ~F_HAVE_BLCKD_MSCHED;
-	    break;
-	case ERTS_SCHDLR_SSPND_EINVAL:
-	default:
-	    erts_exit(ERTS_ABORT_EXIT, "%s:%d: Internal error: %d\n",
-		     __FILE__, __LINE__, (int) ssr);
-	}
-    }
 
-    if (p->flags & F_USING_DB) {
-	if (erts_db_process_exiting(p, ERTS_PROC_LOCK_MAIN))
-	    goto yield;
-	p->flags &= ~F_USING_DB;
-    }
+    switch (trap_state->phase) {
+    case ERTS_CONTINUE_EXIT_TIMERS:
+        if (p->bif_timers) {
+            reds = erts_cancel_bif_timers(p, &p->bif_timers, &trap_state->yield_state, reds);
+            if (reds <= 0) goto yield;
+            p->bif_timers = NULL;
+        }
 
-    erts_set_gc_state(p, 1);
-    state = erts_atomic32_read_acqb(&p->state);
-    if ((state & ERTS_PSFLG_SYS_TASKS) || p->dirty_sys_tasks) {
-	if (cleanup_sys_tasks(p, state, CONTEXT_REDS) >= CONTEXT_REDS/2)
-	    goto yield;
-    }
+        if (p->flags & F_SCHDLR_ONLN_WAITQ) {
+            abort_sched_onln_chng_waitq(p);
+            reds -= 100;
+        }
 
-#ifdef DEBUG
-    erts_proc_lock(p, ERTS_PROC_LOCK_STATUS);
-    ASSERT(ERTS_PROC_GET_DELAYED_GC_TASK_QS(p) == NULL);
-    ASSERT(p->dirty_sys_tasks == NULL);
-    erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
-#endif
+        trap_state->phase = ERTS_CONTINUE_EXIT_BLCKD_MSHED;
+        if (reds <= 0) goto yield;
+    case ERTS_CONTINUE_EXIT_BLCKD_MSHED:
+
+        if (p->flags & F_HAVE_BLCKD_MSCHED) {
+            ErtsSchedSuspendResult ssr;
+            ssr = erts_block_multi_scheduling(p, ERTS_PROC_LOCK_MAIN, 0, 0, 1);
+            switch (ssr) {
+            case ERTS_SCHDLR_SSPND_DONE:
+            case ERTS_SCHDLR_SSPND_DONE_MSCHED_BLOCKED:
+            case ERTS_SCHDLR_SSPND_DONE_NMSCHED_BLOCKED:
+                p->flags &= ~F_HAVE_BLCKD_MSCHED;
+                break;
+            default:
+                erts_exit(ERTS_ABORT_EXIT, "%s:%d: Internal error: %d\n",
+                          __FILE__, __LINE__, (int) ssr);
+            }
+            reds -= 100;
+        }
 
-    if (p->flags & F_USING_DDLL) {
-	erts_ddll_proc_dead(p, ERTS_PROC_LOCK_MAIN);
-	p->flags &= ~F_USING_DDLL;
-    }
+        trap_state->phase = ERTS_CONTINUE_EXIT_BLCKD_NMSHED;
+        if (reds <= 0) goto yield;
+    case ERTS_CONTINUE_EXIT_BLCKD_NMSHED:
+
+        if (p->flags & F_HAVE_BLCKD_NMSCHED) {
+            ErtsSchedSuspendResult ssr;
+            ssr = erts_block_multi_scheduling(p, ERTS_PROC_LOCK_MAIN, 0, 1, 1);
+            switch (ssr) {
+            case ERTS_SCHDLR_SSPND_DONE:
+            case ERTS_SCHDLR_SSPND_DONE_MSCHED_BLOCKED:
+            case ERTS_SCHDLR_SSPND_DONE_NMSCHED_BLOCKED:
+                p->flags &= ~F_HAVE_BLCKD_MSCHED;
+                break;
+            default:
+                erts_exit(ERTS_ABORT_EXIT, "%s:%d: Internal error: %d\n",
+                          __FILE__, __LINE__, (int) ssr);
+            }
+            reds -= 100;
+        }
 
-    /*
-     * The registered name *should* be the last "erlang resource" to
-     * cleanup.
-     */
-    if (p->common.u.alive.reg) {
-	(void) erts_unregister_name(p, ERTS_PROC_LOCK_MAIN, NULL, THE_NON_VALUE);
-	ASSERT(!p->common.u.alive.reg);
-    }
+        trap_state->yield_state = NULL;
+        trap_state->phase = ERTS_CONTINUE_EXIT_USING_DB;
+        if (reds <= 0) goto yield;
+    case ERTS_CONTINUE_EXIT_USING_DB:
 
-    if (IS_TRACED_FL(p, F_TRACE_SCHED_EXIT))
-        trace_sched(p, curr_locks, am_out_exited);
+        if (p->flags & F_USING_DB) {
+            if (erts_db_process_exiting(p, ERTS_PROC_LOCK_MAIN, &trap_state->yield_state))
+                goto yield;
+            p->flags &= ~F_USING_DB;
+        }
 
-    erts_proc_lock(p, ERTS_PROC_LOCKS_ALL_MINOR);
-    curr_locks = ERTS_PROC_LOCKS_ALL;
+        erts_set_gc_state(p, 1);
+
+        trap_state->phase = ERTS_CONTINUE_EXIT_CLEAN_SYS_TASKS;
+    case ERTS_CONTINUE_EXIT_CLEAN_SYS_TASKS:
+        
+        state = erts_atomic32_read_acqb(&p->state);
+        if ((state & ERTS_PSFLG_SYS_TASKS) || p->dirty_sys_tasks) {
+            reds -= cleanup_sys_tasks(p, state, reds);
+            if (reds <= 0) goto yield;
+        }
+
+        trap_state->phase = ERTS_CONTINUE_EXIT_FREE;
+    case ERTS_CONTINUE_EXIT_FREE:
 
-    /*
-     * From this point on we are no longer allowed to yield
-     * this process.
-     */
 #ifdef DEBUG
-    yield_allowed = 0;
+        erts_proc_lock(p, ERTS_PROC_LOCK_STATUS);
+        ASSERT(ERTS_PROC_GET_DELAYED_GC_TASK_QS(p) == NULL);
+        ASSERT(p->dirty_sys_tasks == NULL);
+        erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
 #endif
 
-    /*
-     * Note! The monitor and link fields will be overwritten 
-     * by erts_ptab_delete_element() below.
-     */
-    links = ERTS_P_LINKS(p);
-    monitors = ERTS_P_MONITORS(p);
-    lt_monitors = ERTS_P_LT_MONITORS(p);
+        if (p->flags & F_USING_DDLL) {
+            erts_ddll_proc_dead(p, ERTS_PROC_LOCK_MAIN);
+            p->flags &= ~F_USING_DDLL;
+        }
 
-    {
-	/* Do *not* use erts_get_runq_proc() */
-	ErtsRunQueue *rq;
-	rq = erts_get_runq_current(erts_proc_sched_data(p));
+        /*
+         * The registered name *should* be the last "erlang resource" to
+         * cleanup.
+         */
+        if (p->common.u.alive.reg) {
+            (void) erts_unregister_name(p, ERTS_PROC_LOCK_MAIN, NULL, THE_NON_VALUE);
+            ASSERT(!p->common.u.alive.reg);
+        }
 
-	erts_runq_lock(rq);
+        erts_proc_lock(p, ERTS_PROC_LOCKS_ALL_MINOR);
+        curr_locks = ERTS_PROC_LOCKS_ALL;
 
-	ASSERT(p->scheduler_data);
-	ASSERT(p->scheduler_data->current_process == p);
-	ASSERT(p->scheduler_data->free_process == NULL);
+        /*
+         * Note! The monitor and link fields will be overwritten 
+         * by erts_ptab_delete_element() below.
+         */
+        trap_state->links = ERTS_P_LINKS(p);
+        trap_state->monitors = ERTS_P_MONITORS(p);
+        trap_state->lt_monitors = ERTS_P_LT_MONITORS(p);
 
-	p->scheduler_data->current_process = NULL;
-	p->scheduler_data->free_process = p;
+        {
+            /* Do *not* use erts_get_runq_proc() */
+            ErtsRunQueue *rq;
+            rq = erts_get_runq_current(erts_proc_sched_data(p));
 
-	/* Time of death! */
-	erts_ptab_delete_element(&erts_proc, &p->common);
+            erts_runq_lock(rq);
 
-	erts_runq_unlock(rq);
-    }
+            ASSERT(p->scheduler_data);
+            ASSERT(p->scheduler_data->current_process == p);
+            ASSERT(p->scheduler_data->free_process == NULL);
 
-    /*
-     * All "erlang resources" have to be deallocated before this point,
-     * e.g. registered name, so monitoring and linked processes can
-     * be sure that all interesting resources have been deallocated
-     * when the monitors and/or links hit.
-     */
+            /* Time of death! */
+            erts_ptab_delete_element(&erts_proc, &p->common);
 
-    {
-	/* Inactivate and notify free */
-	erts_aint32_t n, e, a = erts_atomic32_read_nob(&p->state);
-	int refc_inced = 0;
-	while (1) {
-	    n = e = a;
-	    ASSERT(a & ERTS_PSFLG_EXITING);
-	    n |= ERTS_PSFLG_FREE;
-	    n &= ~(ERTS_PSFLG_ACTIVE
-                   | ERTS_PSFLG_ACTIVE_SYS
-                   | ERTS_PSFLG_DIRTY_ACTIVE_SYS);
-	    if ((n & ERTS_PSFLG_IN_RUNQ) && !refc_inced) {
-		erts_proc_inc_refc(p);
-		refc_inced = 1;
-	    }
-	    a = erts_atomic32_cmpxchg_mb(&p->state, n, e);
-	    if (a == e)
-		break;
-	}
+            erts_runq_unlock(rq);
+        }
 
-        if (a & (ERTS_PSFLG_DIRTY_RUNNING
-                 | ERTS_PSFLG_DIRTY_RUNNING_SYS)) {
-	    p->flags |= F_DELAYED_DEL_PROC;
-	    delay_del_proc = 1;
-	    /*
-	     * The dirty scheduler decrease refc
-             * when done with the process...
-	     */
-	}
+        /*
+         * All "erlang resources" have to be deallocated before this point,
+         * e.g. registered name, so monitoring and linked processes can
+         * be sure that all interesting resources have been deallocated
+         * when the monitors and/or links hit.
+         */
 
-	if (refc_inced && !(n & ERTS_PSFLG_IN_RUNQ))
-	    erts_proc_dec_refc(p);
-    }
+        {
+            /* Inactivate and notify free */
+            erts_aint32_t n, e, a = erts_atomic32_read_nob(&p->state);
+            int refc_inced = 0;
+            while (1) {
+                n = e = a;
+                ASSERT(a & ERTS_PSFLG_EXITING);
+                n |= ERTS_PSFLG_FREE;
+                if ((n & ERTS_PSFLG_IN_RUNQ) && !refc_inced) {
+                    erts_proc_inc_refc(p);
+                    refc_inced = 1;
+                }
+                a = erts_atomic32_cmpxchg_mb(&p->state, n, e);
+                if (a == e)
+                    break;
+            }
+
+            if (refc_inced && !(n & ERTS_PSFLG_IN_RUNQ))
+                erts_proc_dec_refc(p);
+        }
 
-    dep = ((p->flags & F_DISTRIBUTION)
-           ? ERTS_PROC_SET_DIST_ENTRY(p, NULL)
-           : NULL);
+        trap_state->dep = ((p->flags & F_DISTRIBUTION)
+                      ? ERTS_PROC_SET_DIST_ENTRY(p, NULL)
+                      : NULL);
 
 
-    /*
-     * It might show up signal prio elevation tasks until we
-     * have entered free state. Cleanup such tasks now.
-     */
-    state = erts_atomic32_read_acqb(&p->state);
-    if (!(state & ERTS_PSFLG_SYS_TASKS))
-        erts_proc_unlock(p, ERTS_PROC_LOCKS_ALL);
-    else {
         erts_proc_unlock(p, ERTS_PROC_LOCKS_ALL_MINOR);
+        curr_locks = ERTS_PROC_LOCK_MAIN;
+        trap_state->phase = ERTS_CONTINUE_EXIT_CLEAN_SYS_TASKS_AFTER;
+    case ERTS_CONTINUE_EXIT_CLEAN_SYS_TASKS_AFTER:
+        /*
+         * It might show up signal prio elevation tasks until we
+         * have entered free state. Cleanup such tasks now.
+         */
 
-        do {
-            (void) cleanup_sys_tasks(p, state, CONTEXT_REDS);
-            state = erts_atomic32_read_acqb(&p->state);
-        } while (state & ERTS_PSFLG_SYS_TASKS);
-        
-        erts_proc_unlock(p, ERTS_PROC_LOCK_MAIN);
-    }
+        state = erts_atomic32_read_acqb(&p->state);
+        if ((state & ERTS_PSFLG_SYS_TASKS) || p->dirty_sys_tasks) {
+            reds -= cleanup_sys_tasks(p, state, reds);
+            if (reds <= 0) goto yield;
+        }
+
+        /* Needs to be unlocked for erts_do_net_exits to work?!? */
+        // erts_proc_unlock(p, ERTS_PROC_LOCK_MAIN);
 
 #ifdef DEBUG
-    erts_proc_lock(p, ERTS_PROC_LOCK_STATUS);
-    ASSERT(p->sys_task_qs == NULL);
-    erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+        erts_proc_lock(p, ERTS_PROC_LOCK_STATUS);
+        ASSERT(p->sys_task_qs == NULL);
+        erts_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
 #endif
 
-    if (dep) {
-        erts_do_net_exits(dep, (reason == am_kill) ? am_killed : reason);
-        erts_deref_dist_entry(dep);
-    }
+        if (trap_state->dep) {
+            erts_do_net_exits(trap_state->dep,
+                              (trap_state->reason == am_kill) ? am_killed : trap_state->reason);
+            erts_deref_dist_entry(trap_state->dep);
+        }
 
-    pectxt.c_p = p;
-    pectxt.reason = reason;
+        trap_state->pectxt.c_p = p;
+        trap_state->pectxt.reason = trap_state->reason;
+
+        erts_proc_lock(p, ERTS_PROC_LOCK_MSGQ);
+
+        erts_proc_sig_fetch(p);
+
+        erts_proc_unlock(p, ERTS_PROC_LOCK_MSGQ);
+
+        reds -= 1000;
+
+        trap_state->yield_state = NULL;
+        trap_state->phase = ERTS_CONTINUE_EXIT_LINKS;
+        if (reds <= 0) goto yield;
+    case ERTS_CONTINUE_EXIT_LINKS:
+
+        reds = erts_link_tree_foreach_delete_yielding(
+            &trap_state->links,
+            erts_proc_exit_handle_link,
+            (void *) &trap_state->pectxt,
+            &trap_state->yield_state,
+            reds);
+        if (reds <= 0)
+            goto yield;
+
+        ASSERT(!trap_state->links);
+        trap_state->yield_state = NULL;
+        trap_state->phase = ERTS_CONTINUE_EXIT_MONITORS;
+    case ERTS_CONTINUE_EXIT_MONITORS:
+
+    reds = erts_monitor_tree_foreach_delete_yielding(
+            &trap_state->monitors,
+            erts_proc_exit_handle_monitor,
+            (void *) &trap_state->pectxt,
+            &trap_state->yield_state,
+            reds);
+        if (reds <= 0)
+            goto yield;
+
+        ASSERT(!trap_state->monitors);
+        trap_state->yield_state = NULL;
+        trap_state->phase = ERTS_CONTINUE_EXIT_LT_MONITORS;
+    case ERTS_CONTINUE_EXIT_LT_MONITORS:
+
+        reds = erts_monitor_list_foreach_delete_yielding(
+            &trap_state->lt_monitors,
+            erts_proc_exit_handle_monitor,
+            (void *) &trap_state->pectxt,
+            &trap_state->yield_state,
+            reds);
+        if (reds <= 0)
+            goto yield;
+
+        ASSERT(!trap_state->lt_monitors);
+        trap_state->phase = ERTS_CONTINUE_EXIT_HANDLE_PROC_SIG;
+    case ERTS_CONTINUE_EXIT_HANDLE_PROC_SIG: {
+        Sint r = reds;
+        erts_aint_t state;
+
+        if (!erts_proc_sig_handle_exit(p, &r))
+            goto yield;
+
+        reds -= r;
 
-    erts_proc_lock(p, ERTS_PROC_LOCK_MAIN|ERTS_PROC_LOCK_MSGQ);
+        /*
+         * From this point on we are no longer allowed to yield
+         * this process.
+         */
 
-    erts_proc_sig_fetch(p);
+        /* Set state to not active as we don't want this process
+           to be scheduled in again after this. */
+        state = erts_atomic32_read_band_relb(&p->state,
+                                             ~(ERTS_PSFLG_ACTIVE
+                                               | ERTS_PSFLG_ACTIVE_SYS
+                                               | ERTS_PSFLG_DIRTY_ACTIVE_SYS));
 
-    erts_proc_unlock(p, ERTS_PROC_LOCK_MSGQ);
+        ASSERT(p->scheduler_data);
+        ASSERT(p->scheduler_data->current_process == p);
+        ASSERT(p->scheduler_data->free_process == NULL);
 
-    if (links) {
-        erts_link_tree_foreach_delete(&links,
-                                      erts_proc_exit_handle_link,
-                                      (void *) &pectxt);
-        ASSERT(!links);
-    }
+        p->scheduler_data->current_process = NULL;
+        p->scheduler_data->free_process = p;
 
-    if (monitors) {
-        erts_monitor_tree_foreach_delete(&monitors,
-                                         erts_proc_exit_handle_monitor,
-                                         (void *) &pectxt);
-        ASSERT(!monitors);
-    }
+        if (state & (ERTS_PSFLG_DIRTY_RUNNING
+                     | ERTS_PSFLG_DIRTY_RUNNING_SYS)) {
+            p->flags |= F_DELAYED_DEL_PROC;
+            delay_del_proc = 1;
+            /*
+             * The dirty scheduler decrease refc
+             * when done with the process...
+             */
+        }
 
-    if (lt_monitors) {
-        erts_monitor_list_foreach_delete(&lt_monitors,
-                                         erts_proc_exit_handle_monitor,
-                                         (void *) &pectxt);
-        ASSERT(!lt_monitors);
-    }
+        erts_schedule_thr_prgr_later_cleanup_op(
+            (void (*)(void*))erts_proc_dec_refc,
+            (void *) &p->common,
+            &p->common.u.release,
+            sizeof(Process));
 
-    /*
-     * erts_proc_sig_handle_exit() implements yielding.
-     * However, this function cannot handle it yet... loop
-     * until done...
-     */
-    while (!0) {
-        int reds = CONTEXT_REDS;
-        if (erts_proc_sig_handle_exit(p, &reds))
-            break;
+#ifdef DEBUG
+        yield_allowed = 0;
+#endif
+        break;
+    }
     }
 
+    if (trap_state != &static_state) {
+        erts_free(ERTS_ALC_T_CONT_EXIT_TRAP, trap_state);
+        p->u.terminate = NULL;
+    }
+    
     ERTS_CHK_HAVE_ONLY_MAIN_PROC_LOCK(p);
 
+    if (IS_TRACED_FL(p, F_TRACE_SCHED_EXIT))
+        trace_sched(p, curr_locks, am_out_exited);
+
     erts_flush_trace_messages(p, ERTS_PROC_LOCK_MAIN);
 
     ERTS_TRACER_CLEAR(&ERTS_TRACER(p));
@@ -12639,9 +12721,26 @@ erts_continue_exit_process(Process *p)
 
     ERTS_LC_ASSERT(curr_locks == erts_proc_lc_my_proc_locks(p));
     ERTS_LC_ASSERT(ERTS_PROC_LOCK_MAIN & curr_locks);
+    ASSERT(erts_proc_read_refc(p) > 0);
+
+    if (trap_state == &static_state) {
+        trap_state = erts_alloc(ERTS_ALC_T_CONT_EXIT_TRAP, sizeof(*trap_state));
+        sys_memcpy(trap_state, &static_state, sizeof(*trap_state));
+        p->u.terminate = trap_state;
+    }
+
+    ASSERT(p->scheduler_data);
+    ASSERT(p->scheduler_data->current_process == p);
+    ASSERT(p->scheduler_data->free_process == NULL);
+
+    if (trap_state->phase >= ERTS_CONTINUE_EXIT_FREE) {
+        p->scheduler_data->current_process = NULL;
+        p->scheduler_data->free_process = p;
+    }
 
     p->i = (BeamInstr *) beam_continue_exit;
 
+    /* Why is this lock take??? */
     if (!(curr_locks & ERTS_PROC_LOCK_STATUS)) {
 	erts_proc_lock(p, ERTS_PROC_LOCK_STATUS);
 	curr_locks |= ERTS_PROC_LOCK_STATUS;