WIP snapshot

4 files changed, 32 insertions, 1 deletions

diff --git a/include/litmus/sched_plugin.h b/include/litmus/sched_plugin.h
index 6e7cabdddae8..b5d1ae7bc3b6 100644
--- a/include/litmus/sched_plugin.h
+++ b/include/litmus/sched_plugin.h
@@ -53,6 +53,10 @@ typedef void (*task_block_t)  (struct task_struct *task);
  */
 typedef void (*task_exit_t)    (struct task_struct *);
 
+/* called early before the caller  holds the runqueue lock */
+typedef void (*pre_setsched_t) (struct task_struct *, int policy);
+
+
 /* Called when the current task attempts to create a new lock of a given
  * protocol type. */
 typedef long (*allocate_lock_t) (struct litmus_lock **lock, int type,
@@ -93,6 +97,8 @@ struct sched_plugin {
         task_block_t            task_block;
         task_exit_t             task_exit;
 
+        pre_setsched_t          pre_setsched;
+
 #ifdef CONFIG_LITMUS_LOCKING
         /*      locking protocols       */
         allocate_lock_t         allocate_lock;
diff --git a/kernel/sched.c b/kernel/sched.c
index c5d775079027..b1fd83dbfb47 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4660,6 +4660,9 @@ static int __sched_setscheduler(struct task_struct *p, int policy,
         struct rq *rq;
         int reset_on_fork;
 
+        if (litmus->pre_setsched)
+                litmus->pre_setsched(p, policy);
+
         /* may grab non-irq protected spin_locks */
         BUG_ON(in_interrupt());
 recheck:
diff --git a/litmus/sched_cedf.c b/litmus/sched_cedf.c
index e905c5362d55..f9df2b098493 100644
--- a/litmus/sched_cedf.c
+++ b/litmus/sched_cedf.c
@@ -262,6 +262,8 @@ static noinline void requeue(struct task_struct* task)
 
 #ifdef CONFIG_LITMUS_LOCKING
 static int update_pending_job(cedf_domain_t* cluster, struct task_struct* t);
+static void priodon_become_eligible(void);
+static void priodon_complete_request(void);
 #endif
 
 /* check for any necessary preemptions */
@@ -990,13 +992,26 @@ static void cedf_task_block(struct task_struct *t)
         BUG_ON(!is_realtime(t));
 }
 
+#ifdef CONFIG_LITMUS_LOCKING
+static void cedf_pre_setsched(struct task_struct *t, int policy)
+{
+        /* we can only handle current atm */
+        if (is_realtime(t) && t == current) {
+                TRACE_CUR("cedf_pre_setsched\n");
+
+                /* Pretend to issue a request to make sure
+                 * we are no longer a priority donor. */
+                priodon_become_eligible();
+                priodon_complete_request();
+        }
+}
+#endif
 
 static void cedf_task_exit(struct task_struct * t)
 {
         unsigned long flags;
         cedf_domain_t *cluster = task_cpu_cluster(t);
 
-
         /* unlink if necessary */
         raw_spin_lock_irqsave(&cluster->cluster_lock, flags);
 
@@ -1464,6 +1479,7 @@ static struct sched_plugin cedf_plugin __cacheline_aligned_in_smp = {
         .activate_plugin        = cedf_activate_plugin,
 #ifdef CONFIG_LITMUS_LOCKING
         .allocate_lock          = cedf_allocate_lock,
+        .pre_setsched           = cedf_pre_setsched,
 #endif
 };
 
diff --git a/litmus/sched_plugin.c b/litmus/sched_plugin.c
index 00a1900d6457..950fe5e6a1ab 100644
--- a/litmus/sched_plugin.c
+++ b/litmus/sched_plugin.c
@@ -95,6 +95,11 @@ static void litmus_dummy_task_exit(struct task_struct *task)
 {
 }
 
+static void litmus_dummy_pre_setsched(struct task_struct *task, int policy)
+{
+}
+
+
 static long litmus_dummy_complete_job(void)
 {
         return -ENOSYS;
@@ -178,6 +183,7 @@ int register_sched_plugin(struct sched_plugin* plugin)
         CHECK(allocate_lock);
 #endif
         CHECK(admit_task);
+        CHECK(pre_setsched);
 
         if (!plugin->release_at)
                 plugin->release_at = release_at;