Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched-devel

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched-devel:
  sched: don't allow rt_runtime_us to be zero for groups having rt tasks
  sched: rt-group: fixup schedulability constraints calculation
  sched: fix the wrong time slice value for SCHED_FIFO tasks
  sched: export task_nice
  sched: balance RT task resched only on runqueue
  sched: retain vruntime

4 files changed, 49 insertions, 11 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 9ae4030067a9..11d8e9a74eff 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -899,6 +899,10 @@ struct sched_class {
                              int running);
         void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
                              int oldprio, int running);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+        void (*moved_group) (struct task_struct *p);
+#endif
 };
 
 struct load_weight {
diff --git a/kernel/sched.c b/kernel/sched.c
index dcd553cc4ee8..52b98675acb2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4422,7 +4422,7 @@ int task_nice(const struct task_struct *p)
 {
         return TASK_NICE(p);
 }
-EXPORT_SYMBOL_GPL(task_nice);
+EXPORT_SYMBOL(task_nice);
 
 /**
  * idle_cpu - is a given cpu idle currently?
@@ -5100,7 +5100,7 @@ long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval)
         time_slice = 0;
         if (p->policy == SCHED_RR) {
                 time_slice = DEF_TIMESLICE;
-        } else {
+        } else if (p->policy != SCHED_FIFO) {
                 struct sched_entity *se = &p->se;
                 unsigned long flags;
                 struct rq *rq;
@@ -7625,6 +7625,11 @@ void sched_move_task(struct task_struct *tsk)
 
         set_task_rq(tsk, task_cpu(tsk));
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
+        if (tsk->sched_class->moved_group)
+                tsk->sched_class->moved_group(tsk);
+#endif
+
         if (on_rq) {
                 if (unlikely(running))
                         tsk->sched_class->set_curr_task(rq);
@@ -7721,9 +7726,7 @@ static unsigned long to_ratio(u64 period, u64 runtime)
         if (runtime == RUNTIME_INF)
                 return 1ULL << 16;
 
-        runtime *= (1ULL << 16);
-        div64_64(runtime, period);
-        return runtime;
+        return div64_64(runtime << 16, period);
 }
 
 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
@@ -7747,25 +7750,40 @@ static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
         return total + to_ratio(period, runtime) < global_ratio;
 }
 
+/* Must be called with tasklist_lock held */
+static inline int tg_has_rt_tasks(struct task_group *tg)
+{
+        struct task_struct *g, *p;
+        do_each_thread(g, p) {
+                if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
+                        return 1;
+        } while_each_thread(g, p);
+        return 0;
+}
+
 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
 {
         u64 rt_runtime, rt_period;
         int err = 0;
 
-        rt_period = sysctl_sched_rt_period * NSEC_PER_USEC;
+        rt_period = (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
         rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
         if (rt_runtime_us == -1)
-                rt_runtime = rt_period;
+                rt_runtime = RUNTIME_INF;
 
         mutex_lock(&rt_constraints_mutex);
+        read_lock(&tasklist_lock);
+        if (rt_runtime_us == 0 && tg_has_rt_tasks(tg)) {
+                err = -EBUSY;
+                goto unlock;
+        }
         if (!__rt_schedulable(tg, rt_period, rt_runtime)) {
                 err = -EINVAL;
                 goto unlock;
         }
-        if (rt_runtime_us == -1)
-                rt_runtime = RUNTIME_INF;
         tg->rt_runtime = rt_runtime;
  unlock:
+        read_unlock(&tasklist_lock);
         mutex_unlock(&rt_constraints_mutex);
 
         return err;
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 3df4d46994ca..e2a530515619 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1353,6 +1353,16 @@ static void set_curr_task_fair(struct rq *rq)
                 set_next_entity(cfs_rq_of(se), se);
 }
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void moved_group_fair(struct task_struct *p)
+{
+        struct cfs_rq *cfs_rq = task_cfs_rq(p);
+
+        update_curr(cfs_rq);
+        place_entity(cfs_rq, &p->se, 1);
+}
+#endif
+
 /*
  * All the scheduling class methods:
  */
@@ -1381,6 +1391,10 @@ static const struct sched_class fair_sched_class = {
 
         .prio_changed           = prio_changed_fair,
         .switched_to            = switched_to_fair,
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+        .moved_group            = moved_group_fair,
+#endif
 };
 
 #ifdef CONFIG_SCHED_DEBUG
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 76e828517541..0a6d2e516420 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1107,9 +1107,11 @@ static void prio_changed_rt(struct rq *rq, struct task_struct *p,
                         pull_rt_task(rq);
                 /*
                  * If there's a higher priority task waiting to run
-                 * then reschedule.
+                 * then reschedule. Note, the above pull_rt_task
+                 * can release the rq lock and p could migrate.
+                 * Only reschedule if p is still on the same runqueue.
                  */
-                if (p->prio > rq->rt.highest_prio)
+                if (p->prio > rq->rt.highest_prio && rq->curr == p)
                         resched_task(p);
 #else
                 /* For UP simply resched on drop of prio */