1 files changed, 27 insertions, 14 deletions

diff --git a/litmus/sched_cedf.c b/litmus/sched_cedf.c
index e78ff0ade237..99f7620925ba 100644
--- a/litmus/sched_cedf.c
+++ b/litmus/sched_cedf.c
@@ -504,7 +504,6 @@ static void do_lit_tasklets(cedf_domain_t* cluster, struct task_struct* sched_ta
 
                 TS_NV_SCHED_BOTISR_START;
 
-                // remove tasklet at head of list if it has higher priority.
                 raw_spin_lock_irqsave(&cluster->cluster_lock, flags);
 
                 if(cluster->pending_tasklets.head != NULL) {
@@ -512,25 +511,35 @@ static void do_lit_tasklets(cedf_domain_t* cluster, struct task_struct* sched_ta
                         struct tasklet_struct *prev = NULL;
                         tasklet = cluster->pending_tasklets.head;
 
-                        while(tasklet && edf_higher_prio(sched_task, tasklet->owner)) {
+                        // find a tasklet with prio to execute; skip ones where
+                        // sched_task has a higher priority.
+                        // We use the '!edf' test instead of swaping function arguments since
+                        // both sched_task and owner could be NULL.  In this case, we want to
+                        // still execute the tasklet.
+                        while(tasklet && !edf_higher_prio(tasklet->owner, sched_task)) {
                                 prev = tasklet;
                                 tasklet = tasklet->next;
                         }
 
-                        // remove the tasklet from the queue
-                        if(prev) {
-                                prev->next = tasklet->next;
-                                if(prev->next == NULL) {
-                                        TRACE("%s: Tasklet for %d is the last element in tasklet queue.\n", __FUNCTION__, tasklet->owner->pid);
-                                        cluster->pending_tasklets.tail = &(prev);
+                        if(tasklet) {  // found something to execuite
+                                // remove the tasklet from the queue
+                                if(prev) {
+                                        prev->next = tasklet->next;
+                                        if(prev->next == NULL) {
+                                                TRACE("%s: Tasklet for %d is the last element in tasklet queue.\n", __FUNCTION__, tasklet->owner->pid);
+                                                cluster->pending_tasklets.tail = &(prev);
+                                        }
+                                }
+                                else {
+                                        cluster->pending_tasklets.head = tasklet->next;
+                                        if(tasklet->next == NULL) {
+                                                TRACE("%s: Tasklet for %d is the last element in tasklet queue.\n", __FUNCTION__, tasklet->owner->pid);
+                                                cluster->pending_tasklets.tail = &(cluster->pending_tasklets.head);
+                                        }
                                 }
                         }
                         else {
-                                cluster->pending_tasklets.head = tasklet->next;
-                                if(tasklet->next == NULL) {
-                                        TRACE("%s: Tasklet for %d is the last element in tasklet queue.\n", __FUNCTION__, tasklet->owner->pid);
-                                        cluster->pending_tasklets.tail = &(cluster->pending_tasklets.head);
-                                }
+                                TRACE("%s: No tasklets with eligible priority.\n", __FUNCTION__);
                         }
                 }
                 else {
@@ -629,6 +638,7 @@ static void cedf_run_tasklets(struct task_struct* sched_task)
 
 static int cedf_enqueue_pai_tasklet(struct tasklet_struct* tasklet)
 {
+#if 0
         cedf_domain_t *cluster = NULL;
         cpu_entry_t *targetCPU = NULL;
         int thisCPU;
@@ -709,7 +719,10 @@ static int cedf_enqueue_pai_tasklet(struct tasklet_struct* tasklet)
         else {
                 TRACE("%s: Scheduling of tasklet was deferred.\n", __FUNCTION__);
         }
-
+#else
+        TRACE("%s: Running tasklet on CPU where it was received.\n", __FUNCTION__);
+        __do_lit_tasklet(tasklet, 0ul);
+#endif
         return(1); // success
 }