LITMUS 2008: Initial Port

This introduces the core changes ported from LITMUS 2007.
The kernel seems to work under QEMU, but many bugs probably remain.

5 files changed, 42 insertions, 5 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 549c0558ba..bc313b74a1 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -52,6 +52,8 @@
 
 extern void sem_exit (void);
 
+extern void exit_od_table(struct task_struct* t);
+
 static void exit_mm(struct task_struct * tsk);
 
 static void __unhash_process(struct task_struct *p)
@@ -987,6 +989,8 @@ fastcall NORET_TYPE void do_exit(long code)
         if (unlikely(tsk->audit_context))
                 audit_free(tsk);
 
+        exit_od_table(tsk);
+
         tsk->exit_code = code;
         taskstats_exit(tsk, group_dead);
 
diff --git a/kernel/fork.c b/kernel/fork.c
index 8dd8ff2810..9e42d3a207 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -59,6 +59,9 @@
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
 
+#include <litmus/litmus.h>
+#include <litmus/sched_plugin.h>
+
 /*
  * Protected counters by write_lock_irq(&tasklist_lock)
  */
@@ -121,6 +124,8 @@ void __put_task_struct(struct task_struct *tsk)
         WARN_ON(atomic_read(&tsk->usage));
         WARN_ON(tsk == current);
 
+        exit_litmus(tsk);
+
         security_task_free(tsk);
         free_uid(tsk->user);
         put_group_info(tsk->group_info);
diff --git a/kernel/sched.c b/kernel/sched.c
index e76b11ca6d..4890a12786 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -324,6 +324,8 @@ struct rq {
 
         atomic_t nr_iowait;
 
+        struct task_struct* litmus_next;
+
 #ifdef CONFIG_SMP
         struct sched_domain *sd;
 
@@ -875,11 +877,12 @@ static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
 #include "sched_idletask.c"
 #include "sched_fair.c"
 #include "sched_rt.c"
+#include "../litmus/sched_litmus.c"
 #ifdef CONFIG_SCHED_DEBUG
 # include "sched_debug.c"
 #endif
 
-#define sched_class_highest (&rt_sched_class)
+#define sched_class_highest (&litmus_sched_class)
 
 /*
  * Update delta_exec, delta_fair fields for rq.
@@ -1529,7 +1532,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
         this_cpu = smp_processor_id();
 
 #ifdef CONFIG_SMP
-        if (unlikely(task_running(rq, p)))
+        if (unlikely(task_running(rq, p) || is_realtime(p)))
                 goto out_activate;
 
         new_cpu = cpu;
@@ -1890,6 +1893,7 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
          */
         prev_state = prev->state;
         finish_arch_switch(prev);
+        litmus->finish_switch(prev);
         finish_lock_switch(rq, prev);
         fire_sched_in_preempt_notifiers(current);
         if (mm)
@@ -3491,6 +3495,7 @@ void scheduler_tick(void)
         update_cpu_load(rq);
         if (curr != rq->idle) /* FIXME: needed? */
                 curr->sched_class->task_tick(rq, curr);
+        litmus_tick(rq, curr);
         spin_unlock(&rq->lock);
 
 #ifdef CONFIG_SMP
@@ -3641,6 +3646,10 @@ need_resched_nonpreemptible:
          */
         local_irq_disable();
         __update_rq_clock(rq);
+        /* do litmus scheduling outside of rq lock, so that we
+         * can do proper migrations for global schedulers
+         */
+        litmus_schedule(rq, prev);
         spin_lock(&rq->lock);
         clear_tsk_need_resched(prev);
 
@@ -4236,6 +4245,9 @@ __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
         case SCHED_RR:
                 p->sched_class = &rt_sched_class;
                 break;
+        case SCHED_LITMUS:
+                p->sched_class = &litmus_sched_class;
+                break;
         }
 
         p->rt_priority = prio;
@@ -4268,7 +4280,7 @@ recheck:
                 policy = oldpolicy = p->policy;
         else if (policy != SCHED_FIFO && policy != SCHED_RR &&
                         policy != SCHED_NORMAL && policy != SCHED_BATCH &&
-                        policy != SCHED_IDLE)
+                        policy != SCHED_IDLE && policy != SCHED_LITMUS)
                 return -EINVAL;
         /*
          * Valid priorities for SCHED_FIFO and SCHED_RR are
@@ -4282,6 +4294,9 @@ recheck:
         if (rt_policy(policy) != (param->sched_priority != 0))
                 return -EINVAL;
 
+        if (policy == SCHED_LITMUS && policy == p->policy)
+                return -EINVAL;
+
         /*
          * Allow unprivileged RT tasks to decrease priority:
          */
@@ -4316,6 +4331,12 @@ recheck:
                         return -EPERM;
         }
 
+        if (policy == SCHED_LITMUS) {
+                retval = litmus_admit_task(p);
+                if (retval)
+                        return retval;
+        }
+
         retval = security_task_setscheduler(p, policy, param);
         if (retval)
                 return retval;
@@ -4345,9 +4366,15 @@ recheck:
                         p->sched_class->put_prev_task(rq, p);
         }
 
+        if (p->policy == SCHED_LITMUS)
+                litmus_exit_task(p);
+
         oldprio = p->prio;
         __setscheduler(rq, p, policy, param->sched_priority);
 
+        if (policy == SCHED_LITMUS)
+                litmus->task_new(p, on_rq, running);
+
         if (on_rq) {
                 if (running)
                         p->sched_class->set_curr_task(rq);
@@ -4364,6 +4391,7 @@ recheck:
                         check_preempt_curr(rq, p);
                 }
         }
+
         __task_rq_unlock(rq);
         spin_unlock_irqrestore(&p->pi_lock, flags);
 
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index da7c061e72..de30496263 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -845,7 +845,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
         struct sched_entity *se = &curr->se, *pse = &p->se;
         unsigned long gran;
 
-        if (unlikely(rt_prio(p->prio))) {
+        if (unlikely(rt_prio(p->prio) || p->policy == SCHED_LITMUS)) {
                 update_rq_clock(rq);
                 update_curr(cfs_rq);
                 resched_task(curr);
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 9ba3daa034..c7c938cee2 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -70,7 +70,7 @@ yield_task_rt(struct rq *rq)
  */
 static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p)
 {
-        if (p->prio < rq->curr->prio)
+        if (p->prio < rq->curr->prio || p->policy == SCHED_LITMUS)
                 resched_task(rq->curr);
 }