[PATCH 1/6] sched: account SCHED_IDLE tasks on rq->idle_nr_running

[Nikhil Rao <ncrao@google.com>]

Account SCHED_IDLE tasks on rq->idle_nr_running in addition to rq->nr_running.
This is a preparatory patch for the SCHED_IDLE load balancer.

Signed-off-by: Nikhil Rao <ncrao@google.com>
---
 kernel/sched.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index f52a880..26e74e9 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -456,6 +456,7 @@ struct rq {
 	unsigned long nr_running;
 	#define CPU_LOAD_IDX_MAX 5
 	unsigned long cpu_load[CPU_LOAD_IDX_MAX];
+	unsigned long idle_nr_running;
 #ifdef CONFIG_NO_HZ
 	u64 nohz_stamp;
 	unsigned char in_nohz_recently;
@@ -1838,6 +1839,16 @@ static void dec_nr_running(struct rq *rq)
 	rq->nr_running--;
 }
 
+static void inc_idle_nr_running(struct rq *rq)
+{
+	rq->idle_nr_running++;
+}
+
+static void dec_idle_nr_running(struct rq *rq)
+{
+	rq->idle_nr_running--;
+}
+
 static void set_load_weight(struct task_struct *p)
 {
 	if (task_has_rt_policy(p)) {
@@ -1885,6 +1896,8 @@ static void activate_task(struct rq *rq, struct task_struct *p, int flags)
 
 	enqueue_task(rq, p, flags);
 	inc_nr_running(rq);
+	if (p->policy == SCHED_IDLE)
+		inc_idle_nr_running(rq);
 }
 
 /*
@@ -1897,6 +1910,8 @@ static void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
 
 	dequeue_task(rq, p, flags);
 	dec_nr_running(rq);
+	if (p->policy == SCHED_IDLE)
+		dec_idle_nr_running(rq);
 }
 
 #include "sched_idletask.c"
-- 
1.7.1