[PATCH 4/7] sched: Account rr and fifo tasks separately

[Frederic Weisbecker <fweisbec@gmail.com>]

In order to evaluate tick dependency, we need to account SCHED_RR and
SCHED_FIFO tasks separately as those policies don't have the same
preemption requirements.

We still keep rt_nr_running as a cache to avoid additions between nr_rr
and nr_fifo all over the place.

Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 kernel/sched/rt.c    | 34 ++++++++++++++++++++++++++++++++++
 kernel/sched/sched.h |  2 ++
 2 files changed, 36 insertions(+)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index d2ea593..0e80458 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1152,12 +1152,43 @@ unsigned int rt_se_nr_running(struct sched_rt_entity *rt_se)
 }
 
 static inline
+unsigned int rt_se_fifo_nr_running(struct sched_rt_entity *rt_se)
+{
+	struct rt_rq *group_rq = group_rt_rq(rt_se);
+	struct task_struct *tsk;
+
+	if (group_rq)
+		return group_rq->fifo_nr_running;
+
+	tsk = rt_task_of(rt_se);
+
+	return (tsk->policy == SCHED_FIFO) ? 1 : 0;
+}
+
+static inline
+unsigned int rt_se_rr_nr_running(struct sched_rt_entity *rt_se)
+{
+	struct rt_rq *group_rq = group_rt_rq(rt_se);
+	struct task_struct *tsk;
+
+	if (group_rq)
+		return group_rq->rr_nr_running;
+
+	tsk = rt_task_of(rt_se);
+
+	return (tsk->policy == SCHED_RR) ? 1 : 0;
+}
+
+static inline
 void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 {
 	int prio = rt_se_prio(rt_se);
 
 	WARN_ON(!rt_prio(prio));
 	rt_rq->rt_nr_running += rt_se_nr_running(rt_se);
+	rt_rq->fifo_nr_running += rt_se_fifo_nr_running(rt_se);
+	rt_rq->rr_nr_running += rt_se_rr_nr_running(rt_se);
+	WARN_ON_ONCE(rt_rq->rt_nr_running != rt_rq->fifo_nr_running + rt_rq->rr_nr_running);
 
 	inc_rt_prio(rt_rq, prio);
 	inc_rt_migration(rt_se, rt_rq);
@@ -1170,6 +1201,9 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
 	WARN_ON(!rt_prio(rt_se_prio(rt_se)));
 	WARN_ON(!rt_rq->rt_nr_running);
 	rt_rq->rt_nr_running -= rt_se_nr_running(rt_se);
+	rt_rq->fifo_nr_running -= rt_se_fifo_nr_running(rt_se);
+	rt_rq->rr_nr_running -= rt_se_rr_nr_running(rt_se);
+	WARN_ON_ONCE(rt_rq->rt_nr_running != rt_rq->fifo_nr_running + rt_rq->rr_nr_running);
 
 	dec_rt_prio(rt_rq, rt_se_prio(rt_se));
 	dec_rt_migration(rt_se, rt_rq);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 6d2a119..cfafbdd 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -433,6 +433,8 @@ static inline int rt_bandwidth_enabled(void)
 struct rt_rq {
 	struct rt_prio_array active;
 	unsigned int rt_nr_running;
+	unsigned int fifo_nr_running;
+	unsigned int rr_nr_running;
 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
 	struct {
 		int curr; /* highest queued rt task prio */
-- 
2.5.3