Comment about taskmgr exclusive mode, fix a REQUIRE.

diff --git a/lib/isc/task.c b/lib/isc/task.c
index 2d01c9288cd5533dd2de12099e93414bf0a5a9ab..87ece27ec09470184b68d1fb657a2ac2e31365e0 100644 (file)
--- a/lib/isc/task.c
+++ b/lib/isc/task.c
@@ -1015,6 +1015,16 @@ dispatch(isc__taskmgr_t *manager, unsigned int threadid) {
                        XTHREADTRACE(isc_msgcat_get(isc_msgcat, ISC_MSGSET_TASK,
                                            ISC_MSG_WORKING, "halting"));
 
+                       /*
+                        * Switching to exclusive mode is done as a 2-phase-lock,
+                        * checking if we have to switch is done without any locks
+                        * on pause_requested and exclusive_requested to save time -
+                        * the worst thing that can happen is that we'll launch one task
+                        * more and exclusive task will be postponed a bit.
+                        *
+                        * Broadcasting on halt_cond seems suboptimal, but exclusive tasks
+                        * are rare enought that we don't care.
+                        */
                        LOCK(&manager->halt_lock);
                        manager->halted++;
                        BROADCAST(&manager->halt_cond);
@@ -1532,11 +1542,8 @@ isc_task_beginexclusive(isc_task_t *task0) {
        REQUIRE(VALID_TASK(task));
 
        REQUIRE(task->state == task_state_running);
-
-/*
- *  TODO REQUIRE(task == task->manager->excl);
- *  it should be here, it fails on shutdown server->task
- */
+       REQUIRE(task == task->manager->excl ||
+               (task->manager->exiting && task->manager->excl == NULL));
 
        if (manager->exclusive_requested || manager->pause_requested) {
                return (ISC_R_LOCKBUSY);