Fix bugs and add more tracing

1 files changed, 28 insertions, 6 deletions

diff --git a/litmus/sched_mc.c b/litmus/sched_mc.c
index 63dd157925ab..aafe3e095c2a 100644
--- a/litmus/sched_mc.c
+++ b/litmus/sched_mc.c
@@ -343,12 +343,15 @@ static void update_ghost_time(struct task_struct *p)
         delta = clock - p->se.exec_start;
         if (unlikely ((s64)delta < 0)) {
                 delta = 0;
+                TRACE_TASK(p, "WARNING: negative time delta.\n");
         }
         if (p->rt_param.job_params.ghost_budget <= delta) {
+                TRACE_TASK(p, "Ghost job ended in update_ghost_time\n");
                 p->rt_param.job_params.ghost_budget = 0;
                 job_completion(p, 0);
         }
         else{
+                TRACE_TASK(p, "Ghost jub updated, but didn't finish\n");
                 p->rt_param.job_params.ghost_budget -= delta;
                 p->se.exec_start = clock;
         }
@@ -397,6 +400,8 @@ static noinline void link_task_to_cpu(struct task_struct* linked,
                 (linked->rt_param.task_params.cpu != entry->cpu));
 
         if (linked && is_ghost(linked)) {
+                TRACE_TASK(linked, "Linking ghost job to CPU %d.\n",
+                                entry->cpu);
                 BUG_ON(entry->linked &&
                         entry->linked->rt_param.task_params.crit <
                         linked->rt_param.task_params.crit);
@@ -524,12 +529,17 @@ static noinline void unlink(struct task_struct* t)
                 entry = remote_cpu_entry(cpu);
                 t->rt_param.linked_on = NO_CPU;
                 if (is_ghost(t)) {
-                        /* Clear the timer.*/
+                        /* Clear the timer if it's set.
+                         * It may be unset if we are called as a result of
+                         * the watchdog timer triggering.
+                         */
                         timer = ghost_timer(cpu,
                                         t->rt_param.task_params.crit);
-                        /* Should already be watching task.*/
-                        BUG_ON(timer->task != t);
-                        cancel_watchdog_timer(timer);
+                        if (timer->task) {
+                                /* Should already be watching task.*/
+                                BUG_ON(timer->task != t);
+                                cancel_watchdog_timer(timer);
+                        }
                         if (t->rt_param.job_params.ghost_budget > 0){
                                 /* Job isn't finished, so do accounting. */
                                 update_ghost_time(t);
@@ -743,6 +753,7 @@ static noinline void job_completion(struct task_struct *t, int forced)
          * needed.
          */
         if (!is_ghost(t)) {
+                TRACE_TASK(t, "Converting to ghost.\n");
                 cpu = remote_cpu_entry(t->rt_param.scheduled_on);
                 /*Unlink first while it's not a ghost job.*/
                 unlink(t);
@@ -768,6 +779,11 @@ static noinline void job_completion(struct task_struct *t, int forced)
         /* prepare for next period */
         if (is_ghost(t)) {
                 t->rt_param.job_params.ghost_budget = 0;
+                /*Need to unlink here so prepare_for_next_period doesn't try
+                 * to unlink us
+                 */
+                unlink(t);
+                already_unlinked = 1;
                 prepare_for_next_period(t);
         }
         else {
@@ -795,10 +811,16 @@ static enum hrtimer_restart watchdog_timeout(struct hrtimer *timer)
                                                  struct watchdog_timer,
                                                  timer);
         unsigned long flags;
+        struct task_struct* task = wt->task;
         raw_spin_lock_irqsave(&global_lock, flags);
         /*If we have triggered, we know the budget must have expired.*/
-        wt->task->rt_param.job_params.ghost_budget = 0;
-        job_completion(wt->task, 0);
+        /*This needs to run first, so it doesn't look to job_completion like
+         * we have an active timer.
+         */
+        wt->task = NULL;
+        task->rt_param.job_params.ghost_budget = 0;
+        job_completion(task, 0);
+        TRACE_TASK(task, "Watchdog timeout\n");
         raw_spin_unlock_irqrestore(&global_lock, flags);
         return HRTIMER_NORESTART;
 }