[PATCH v4 01/20] Add rt_nr_running accounting

[Steven Rostedt <rostedt@goodmis.org>]

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This patch adds accounting to keep track of the number of RT tasks running
on a runqueue. This information will be used in later patches.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---

 kernel/sched.c    |    1 +
 kernel/sched_rt.c |   17 +++++++++++++++++
 2 files changed, 18 insertions(+)

Index: linux-compile.git/kernel/sched.c
===================================================================
--- linux-compile.git.orig/kernel/sched.c	2007-11-20 19:52:44.000000000 -0500
+++ linux-compile.git/kernel/sched.c	2007-11-20 19:52:50.000000000 -0500
@@ -266,6 +266,7 @@ struct rt_rq {
 	struct rt_prio_array active;
 	int rt_load_balance_idx;
 	struct list_head *rt_load_balance_head, *rt_load_balance_curr;
+	unsigned long rt_nr_running;
 };
 
 /*
Index: linux-compile.git/kernel/sched_rt.c
===================================================================
--- linux-compile.git.orig/kernel/sched_rt.c	2007-11-20 19:52:44.000000000 -0500
+++ linux-compile.git/kernel/sched_rt.c	2007-11-20 19:52:50.000000000 -0500
@@ -25,12 +25,27 @@ static void update_curr_rt(struct rq *rq
 	curr->se.exec_start = rq->clock;
 }
 
+static inline void inc_rt_tasks(struct task_struct *p, struct rq *rq)
+{
+	WARN_ON(!rt_task(p));
+	rq->rt.rt_nr_running++;
+}
+
+static inline void dec_rt_tasks(struct task_struct *p, struct rq *rq)
+{
+	WARN_ON(!rt_task(p));
+	WARN_ON(!rq->rt.rt_nr_running);
+	rq->rt.rt_nr_running--;
+}
+
 static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
 {
 	struct rt_prio_array *array = &rq->rt.active;
 
 	list_add_tail(&p->run_list, array->queue + p->prio);
 	__set_bit(p->prio, array->bitmap);
+
+	inc_rt_tasks(p, rq);
 }
 
 /*
@@ -45,6 +60,8 @@ static void dequeue_task_rt(struct rq *r
 	list_del(&p->run_list);
 	if (list_empty(array->queue + p->prio))
 		__clear_bit(p->prio, array->bitmap);
+
+	dec_rt_tasks(p, rq);
 }
 
 /*

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