Integrate LITMUS^RT scheduling class with sched_setscheduler

2 files changed, 37 insertions, 2 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4fbcc40cb86d..abdf10c424f0 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -91,6 +91,7 @@
 #include <litmus/litmus.h>
 #include <litmus/trace.h>
 #include <litmus/sched_trace.h>
+#include <litmus/sched_plugin.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/sched.h>
@@ -4034,7 +4035,9 @@ static void __setscheduler(struct rq *rq, struct task_struct *p,
         else
                 p->prio = normal_prio(p);
 
-        if (dl_prio(p->prio))
+        if (p->policy == SCHED_LITMUS)
+                p->sched_class = &litmus_sched_class;
+        else if (dl_prio(p->prio))
                 p->sched_class = &dl_sched_class;
         else if (rt_prio(p->prio))
                 p->sched_class = &rt_sched_class;
@@ -4138,6 +4141,7 @@ static int __sched_setscheduler(struct task_struct *p,
         int reset_on_fork;
         int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE;
         struct rq *rq;
+        int litmus_task = 0;
 
         /* may grab non-irq protected spin_locks */
         BUG_ON(in_interrupt());
@@ -4167,6 +4171,8 @@ recheck:
         if ((dl_policy(policy) && !__checkparam_dl(attr)) ||
             (rt_policy(policy) != (attr->sched_priority != 0)))
                 return -EINVAL;
+        if (policy == SCHED_LITMUS && policy == p->policy)
+                return -EINVAL;
 
         /*
          * Allow unprivileged RT tasks to decrease priority:
@@ -4225,6 +4231,12 @@ recheck:
                         return retval;
         }
 
+        if (policy == SCHED_LITMUS) {
+                retval = litmus_admit_task(p);
+                if (retval)
+                        return retval;
+        }
+
         /*
          * make sure no PI-waiters arrive (or leave) while we are
          * changing the priority of the task:
@@ -4308,6 +4320,11 @@ change:
                 return -EBUSY;
         }
 
+        if (is_realtime(p)) {
+                litmus_exit_task(p);
+                litmus_task = 1;
+        }
+
         p->sched_reset_on_fork = reset_on_fork;
         oldprio = p->prio;
 
@@ -4334,6 +4351,16 @@ change:
         prev_class = p->sched_class;
         __setscheduler(rq, p, attr, pi);
 
+        if (litmus_policy(policy)) {
+#ifdef CONFIG_SMP
+                p->rt_param.stack_in_use = running ? rq->cpu : NO_CPU;
+#else
+                p->rt_param.stack_in_use = running ? 0 : NO_CPU;
+#endif
+                p->rt_param.present = running;
+                litmus->task_new(p, queued, running);
+        }
+
         if (queued) {
                 /*
                  * We enqueue to tail when the priority of a task is
@@ -4360,6 +4387,9 @@ change:
         balance_callback(rq);
         preempt_enable();
 
+        if (litmus_task)
+                litmus_dealloc(p);
+
         return 0;
 }
 
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 585b193b2442..34e2f3bd7875 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -113,6 +113,11 @@ static inline int rt_policy(int policy)
         return policy == SCHED_FIFO || policy == SCHED_RR;
 }
 
+static inline int litmus_policy(int policy)
+{
+        return policy == SCHED_LITMUS;
+}
+
 static inline int dl_policy(int policy)
 {
         return policy == SCHED_DEADLINE;
@@ -120,7 +125,7 @@ static inline int dl_policy(int policy)
 static inline bool valid_policy(int policy)
 {
         return idle_policy(policy) || fair_policy(policy) ||
-                rt_policy(policy) || dl_policy(policy);
+                rt_policy(policy) || dl_policy(policy) || litmus_policy(policy);
 }
 
 static inline int task_has_rt_policy(struct task_struct *p)