From faf66ee365f89252dd6367a7549a0b789879ce2e Mon Sep 17 00:00:00 2001
From: Rickard Green <rickard@erlang.org>
Date: Fri, 14 Dec 2012 13:35:30 +0100
Subject: Fix aborts of port tasks when terminating ports

---
 erts/emulator/beam/erl_port_task.c | 66 ++++++++++++++++++++++++++++++++------
 1 file changed, 56 insertions(+), 10 deletions(-)

(limited to 'erts/emulator')

diff --git a/erts/emulator/beam/erl_port_task.c b/erts/emulator/beam/erl_port_task.c
index b661c26036..8ceadcdb8c 100644
--- a/erts/emulator/beam/erl_port_task.c
+++ b/erts/emulator/beam/erl_port_task.c
@@ -120,7 +120,9 @@ struct ErtsPortTaskBusyCallerTable_ {
 };
 
 
-static void begin_port_cleanup(Port *pp, ErtsPortTask **execq);
+static void begin_port_cleanup(Port *pp,
+			       ErtsPortTask **execq,
+			       int *processing_busy_q_p);
 
 ERTS_SCHED_PREF_QUICK_ALLOC_IMPL(port_task,
 				 ErtsPortTask,
@@ -1525,7 +1527,7 @@ erts_port_task_free_port(Port *pp)
 	erts_resume_processes(suspended);
 
     if (!(flags & (ERTS_PTS_FLG_IN_RUNQ|ERTS_PTS_FLG_EXEC)))
-	begin_port_cleanup(pp, NULL);
+	begin_port_cleanup(pp, NULL, NULL);
 }
 
 /*
@@ -1681,8 +1683,7 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
     begin_handle_tasks:
 	if (state & ERTS_PORT_SFLG_FREE) {
 	    reds += ERTS_PORT_REDS_FREE;
-
-	    begin_port_cleanup(pp, &execq);
+	    begin_port_cleanup(pp, &execq, &processing_busy_q);
 
 	    break;
 	}
@@ -1773,22 +1774,66 @@ release_port(void *vport)
 #endif
 
 static void
-begin_port_cleanup(Port *pp, ErtsPortTask **execqp)
+begin_port_cleanup(Port *pp, ErtsPortTask **execqp, int *processing_busy_q_p)
 {
     int i, max;
-    ErtsPortTask *qs[2];
+    ErtsPortTaskBusyCallerTable *tabp;
+    ErtsPortTask *qs[3];
 
     ERTS_SMP_LC_ASSERT(erts_lc_is_port_locked(pp));
 
 
     /*
-     * Handle remaining tasks...
+     * Abort remaining tasks...
+     *
+     * We want to process queues in the following order in order
+     * to preserve signal ordering guarantees:
+     *  1. Local busy queue
+     *  2. Local queue
+     *  3. In queue
      */
 
     max = 0;
-    if (execqp && *execqp) {
-	qs[max++] = *execqp;
+    if (!execqp) {
+	if (pp->sched.taskq.local.busy.first)
+	    qs[max++] = pp->sched.taskq.local.busy.first;
+	if (pp->sched.taskq.local.first)
+	    qs[max++] = pp->sched.taskq.local.first;
+    }
+    else {
+	if (*processing_busy_q_p) {
+	    if (*execqp)
+		qs[max++] = *execqp;
+	    if (pp->sched.taskq.local.first)
+		qs[max++] = pp->sched.taskq.local.first;
+	}
+	else {
+	    if (pp->sched.taskq.local.busy.first)
+		qs[max++] = pp->sched.taskq.local.busy.first;
+	    if (*execqp)
+		qs[max++] = *execqp;
+	}
 	*execqp = NULL;
+	*processing_busy_q_p = 0;
+    }
+    pp->sched.taskq.local.busy.first = NULL;
+    pp->sched.taskq.local.busy.last = NULL;
+    pp->sched.taskq.local.first = NULL;
+    tabp = pp->sched.taskq.local.busy.table;
+    if (tabp) {
+	int bix;
+	for (bix = 0; bix < ERTS_PORT_TASK_BUSY_CALLER_TABLE_BUCKETS; bix++) {
+	    ErtsPortTaskBusyCaller *bcp = tabp->bucket[bix];
+	    while (bcp) {
+		ErtsPortTaskBusyCaller *free_bcp = bcp;
+		bcp = bcp->next;
+		if (free_bcp != &tabp->pre_alloc_busy_caller)
+		    erts_free(ERTS_ALC_T_BUSY_CALLER, free_bcp);
+	    }
+	}
+
+	busy_caller_table_free(tabp);
+	pp->sched.taskq.local.busy.table = NULL;
     }
 
     erts_port_task_sched_lock(&pp->sched);
@@ -1875,7 +1920,8 @@ begin_port_cleanup(Port *pp, ErtsPortTask **execqp)
     }
 
     erts_smp_atomic32_read_band_nob(&pp->sched.flags,
-				    ~ERTS_PTS_FLG_HAVE_TASKS);
+				    ~(ERTS_PTS_FLG_HAVE_BUSY_TASKS
+				      |ERTS_PTS_FLG_HAVE_TASKS));
 
     /*
      * Schedule cleanup of port structure...
-- 
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