[PATCH RFC v2 10/12] Export SCHED_FIFO/RT requeuing functions

From: Bill Huey (hui)
Date: Mon Apr 18 2016 - 02:45:10 EST


SCHED_FIFO/RT tail/head runqueue insertion support, initial thread death
support via a hook to the scheduler class. Thread death must include
additional semantics to remove/discharge an admitted task properly.

Signed-off-by: Bill Huey (hui) <bill.huey@xxxxxxxxx>
---
kernel/sched/rt.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index c41ea7a..1d77adc 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -8,6 +8,11 @@
#include <linux/slab.h>
#include <linux/irq_work.h>

+#ifdef CONFIG_RTC_CYCLIC
+#include "cyclic.h"
+extern int rt_overrun_task_admitted1(struct rq *rq, struct task_struct *p);
+#endif
+
int sched_rr_timeslice = RR_TIMESLICE;

static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
@@ -1321,8 +1326,18 @@ enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)

if (flags & ENQUEUE_WAKEUP)
rt_se->timeout = 0;
+#ifdef CONFIG_RTC_CYCLIC
+ /* if admitted and the current slot then head, otherwise tail */
+ if (rt_overrun_task_admitted1(rq, p)) {
+ if (rt_overrun_task_active(p)) {
+ flags |= ENQUEUE_HEAD;
+ }
+ }

enqueue_rt_entity(rt_se, flags);
+#else
+ enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD);
+#endif

if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
enqueue_pushable_task(rq, p);
@@ -1367,6 +1382,18 @@ static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
}
}

+#ifdef CONFIG_RTC_CYCLIC
+void dequeue_task_rt2(struct rq *rq, struct task_struct *p, int flags)
+{
+ dequeue_task_rt(rq, p, flags);
+}
+
+void requeue_task_rt2(struct rq *rq, struct task_struct *p, int head)
+{
+ requeue_task_rt(rq, p, head);
+}
+#endif
+
static void yield_task_rt(struct rq *rq)
{
requeue_task_rt(rq, rq->curr, 0);
@@ -2177,6 +2204,10 @@ void __init init_sched_rt_class(void)
zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
GFP_KERNEL, cpu_to_node(i));
}
+
+#ifdef CONFIG_RTC_CYCLIC
+ init_rt_overrun();
+#endif
}
#endif /* CONFIG_SMP */

@@ -2322,6 +2353,13 @@ static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
return 0;
}

+#ifdef CONFIG_RTC_CYCLIC
+static void task_dead_rt(struct task_struct *p)
+{
+ rt_overrun_entry_delete(p);
+}
+#endif
+
const struct sched_class rt_sched_class = {
.next = &fair_sched_class,
.enqueue_task = enqueue_task_rt,
@@ -2344,6 +2382,9 @@ const struct sched_class rt_sched_class = {
#endif

.set_curr_task = set_curr_task_rt,
+#ifdef CONFIG_RTC_CYCLIC
+ .task_dead = task_dead_rt,
+#endif
.task_tick = task_tick_rt,

.get_rr_interval = get_rr_interval_rt,
--
2.5.0