Removed flaw which could allow a task to be removed from all queues unnecessarily.

1 files changed, 14 insertions, 19 deletions

diff --git a/litmus/sched_edf_hsb.c b/litmus/sched_edf_hsb.c
index 49cc75d9ea81..8ed59d873e61 100644
--- a/litmus/sched_edf_hsb.c
+++ b/litmus/sched_edf_hsb.c
@@ -999,8 +999,8 @@ static struct task_struct* next_eligible_hrt(hrt_server_t *hrt_server)
             !is_server_linked(&hrt_server->server)) {
 
                 dead = hrt_server->server.deadline;
-                slack = lt_subtract(dead, budget);
                 budget = hrt_server->server.budget;
+                slack = lt_subtract(dead, budget);
 
                 TRACE_SERVER_SUB(&hrt_server->server, "dead: %llu, budget: %llu"
                                  "now: %llu, slack: %llu",
@@ -1376,8 +1376,8 @@ static void preempt(cpu_entry_t *entry, struct task_struct *next,
 
         remove_from_ready(next_server, next, entry);
 
-        linked = entry->linked;
         check_for_slack_preempt(next, next_server, entry, slack_resched);
+        linked = entry->linked;
         link_to_cpu(entry, next, next_server);
 
         /* No need for this if only the server was preempted */
@@ -1396,9 +1396,9 @@ static void preempt(cpu_entry_t *entry, struct task_struct *next,
  * 2. slack donated by server is running a task on a different CPU
  */
 static noinline void check_for_slack_preempt(struct task_struct *task,
-                                    server_t *server,
-                                    cpu_entry_t *next_entry,
-                                    int resched)
+                                            server_t *server,
+                                            cpu_entry_t *next_entry,
+                                            int resched)
 {
         cpu_entry_t *entry = NULL;
         server_t *slack = server_slack(server);
@@ -1410,28 +1410,23 @@ static noinline void check_for_slack_preempt(struct task_struct *task,
 
                 if (entry != next_entry) {
                         TRACE_TASK_SUB(task, "was on P%d", entry->cpu);
+
                         BUG_ON(entry->linked_server->type != S_SLACK &&
                                server->type == S_SLACK && entry->linked_server->type == S_BE);
-
-                        TRACE_SUB("hi");
-
                         BUG_ON(entry->linked_server->type != S_SLACK &&
                                server->type == S_SRT && entry->linked_server->type == S_SRT);
-
-                        TRACE_SUB("hi");
-
                         BUG_ON(entry->linked_server->type != S_SLACK &&
                                server->type == S_SRT);
-
-                        TRACE_SUB("hi");
-
                         BUG_ON(entry->linked_server->type == S_BE && server->type == S_BE);
-
+                        BUG_ON(entry->linked_server->type == S_SRT && server->type == S_SLACK);
                         BUG_ON(entry->linked_server->type != S_SLACK);
 
                         unlink(task);
-                        edf_hsb_pick_next(entry);
-                        preempt_if_preemptable(entry->scheduled, entry->cpu);
+
+                        if (resched) {
+                                edf_hsb_pick_next(entry);
+                                preempt_if_preemptable(entry->scheduled, entry->cpu);
+                        }
                 }
         }
 
@@ -1442,11 +1437,11 @@ static noinline void check_for_slack_preempt(struct task_struct *task,
 
                 unlink(slack_task);
                 remove_slack(slack);
+                requeue(slack_task, get_rt_domain(entry, slack_task));
 
                 if (entry != next_entry && resched) {
                         TRACE_SERVER_SUB(slack, "was on P%d", entry->cpu);
                         /* Force a reschedule */
-                        requeue(slack_task, get_rt_domain(entry, slack_task));
                         edf_hsb_pick_next(entry);
                         preempt_if_preemptable(entry->scheduled, entry->cpu);
                 } else {
@@ -1791,7 +1786,7 @@ static void hrt_server_released(server_t *server)
 
         hrt_server->no_slack = 0;
         hrt_server->ready = 1;
-        remove_slack(&hrt_server->server);
+        remove_slack(server_slack(&hrt_server->server));
 
         check_for_hrt_preempt(entry);