[RFC PATCH v3 07/24] sched/core: Initialize root_task_group

[Yuri Andriaccio <yurand2000@gmail.com>]

From: luca abeni <luca.abeni@santannapisa.it>

Add the initialization function for task_group's dl_servers.
Initialize the default bandwidth for rt-cgroups and the root control group.
Add utility functions to check (and get) if a rt_rq entity is connected to a
real-time cgroup.

Co-developed-by: Alessio Balsini <a.balsini@sssup.it>
Signed-off-by: Alessio Balsini <a.balsini@sssup.it>
Co-developed-by: Andrea Parri <parri.andrea@gmail.com>
Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Co-developed-by: Yuri Andriaccio <yurand2000@gmail.com>
Signed-off-by: Yuri Andriaccio <yurand2000@gmail.com>
Signed-off-by: luca abeni <luca.abeni@santannapisa.it>
---
 kernel/sched/autogroup.c |  4 ++--
 kernel/sched/core.c      |  9 +++++++--
 kernel/sched/deadline.c  |  8 ++++++++
 kernel/sched/rt.c        | 18 ++++++++----------
 kernel/sched/sched.h     | 32 +++++++++++++++++++++++++++++---
 5 files changed, 54 insertions(+), 17 deletions(-)

diff --git a/kernel/sched/autogroup.c b/kernel/sched/autogroup.c
index cdea931aae3..017eadc0a0a 100644
--- a/kernel/sched/autogroup.c
+++ b/kernel/sched/autogroup.c
@@ -52,7 +52,7 @@ static inline void autogroup_destroy(struct kref *kref)
 
 #ifdef CONFIG_RT_GROUP_SCHED
 	/* We've redirected RT tasks to the root task group... */
-	ag->tg->rt_se = NULL;
+	ag->tg->dl_se = NULL;
 	ag->tg->rt_rq = NULL;
 #endif
 	sched_release_group(ag->tg);
@@ -109,7 +109,7 @@ static inline struct autogroup *autogroup_create(void)
 	 * the policy change to proceed.
 	 */
 	free_rt_sched_group(tg);
-	tg->rt_se = root_task_group.rt_se;
+	tg->dl_se = root_task_group.dl_se;
 	tg->rt_rq = root_task_group.rt_rq;
 #endif /* CONFIG_RT_GROUP_SCHED */
 	tg->autogroup = ag;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5791aa1f8c8..e5b4facee24 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8710,7 +8710,7 @@ void __init sched_init(void)
 		scx_tg_init(&root_task_group);
 #endif /* CONFIG_EXT_GROUP_SCHED */
 #ifdef CONFIG_RT_GROUP_SCHED
-		root_task_group.rt_se = (struct sched_rt_entity **)ptr;
+		root_task_group.dl_se = (struct sched_dl_entity **)ptr;
 		ptr += nr_cpu_ids * sizeof(void **);
 
 		root_task_group.rt_rq = (struct rt_rq **)ptr;
@@ -8721,6 +8721,11 @@ void __init sched_init(void)
 
 	init_defrootdomain();
 
+#ifdef CONFIG_RT_GROUP_SCHED
+	init_dl_bandwidth(&root_task_group.dl_bandwidth,
+			global_rt_period(), global_rt_runtime());
+#endif /* CONFIG_RT_GROUP_SCHED */
+
 #ifdef CONFIG_CGROUP_SCHED
 	task_group_cache = KMEM_CACHE(task_group, 0);
 
@@ -8772,7 +8777,7 @@ void __init sched_init(void)
 		 * starts working after scheduler_running, which is not the case
 		 * yet.
 		 */
-		init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
+		init_tg_rt_entry(&root_task_group, rq, NULL, i, NULL);
 #endif
 		rq->sd = NULL;
 		rq->rd = NULL;
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 277fbaff8b5..5c8fe80b585 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -513,6 +513,14 @@ static inline int is_leftmost(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq
 
 static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq);
 
+void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime)
+{
+	raw_spin_lock_init(&dl_b->dl_runtime_lock);
+	dl_b->dl_period = period;
+	dl_b->dl_runtime = runtime;
+}
+
+
 void init_dl_bw(struct dl_bw *dl_b)
 {
 	raw_spin_lock_init(&dl_b->lock);
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index c625ea45ca7..84dbb4853b6 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -97,18 +97,16 @@ void free_rt_sched_group(struct task_group *tg)
 		return;
 }
 
-void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
-		struct sched_rt_entity *rt_se, int cpu,
-		struct sched_rt_entity *parent)
+void init_tg_rt_entry(struct task_group *tg, struct rq *served_rq,
+		struct sched_dl_entity *dl_se, int cpu,
+		struct sched_dl_entity *parent)
 {
-	struct rq *rq = cpu_rq(cpu);
+	served_rq->rt.highest_prio.curr = MAX_RT_PRIO-1;
+	served_rq->rt.rq = cpu_rq(cpu);
+	served_rq->rt.tg = tg;
 
-	rt_rq->highest_prio.curr = MAX_RT_PRIO-1;
-	rt_rq->rq = rq;
-	rt_rq->tg = tg;
-
-	tg->rt_rq[cpu] = rt_rq;
-	tg->rt_se[cpu] = rt_se;
+	tg->rt_rq[cpu] = &served_rq->rt;
+	tg->dl_se[cpu] = dl_se;
 }
 
 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 59a154505d8..d433abe1c9c 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -576,9 +576,9 @@ extern void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
 extern void unthrottle_cfs_rq(struct cfs_rq *cfs_rq);
 extern bool cfs_task_bw_constrained(struct task_struct *p);
 
-extern void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
-		struct sched_rt_entity *rt_se, int cpu,
-		struct sched_rt_entity *parent);
+extern void init_tg_rt_entry(struct task_group *tg, struct rq *s_rq,
+		struct sched_dl_entity *rt_se, int cpu,
+		struct sched_dl_entity *parent);
 extern int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us);
 extern int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us);
 extern long sched_group_rt_runtime(struct task_group *tg);
@@ -2668,6 +2668,7 @@ extern void resched_curr(struct rq *rq);
 extern void resched_curr_lazy(struct rq *rq);
 extern void resched_cpu(int cpu);
 
+void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime);
 extern void init_dl_entity(struct sched_dl_entity *dl_se);
 
 #define BW_SHIFT		20
@@ -3077,6 +3078,21 @@ static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se)
 	WARN_ON(!rt_group_sched_enabled() && rt_rq->tg != &root_task_group);
 	return rt_rq->rq;
 }
+
+static inline int is_dl_group(struct rt_rq *rt_rq)
+{
+	return rt_rq->tg != &root_task_group;
+}
+
+/*
+ * Return the scheduling entity of this group of tasks.
+ */
+static inline struct sched_dl_entity *dl_group_of(struct rt_rq *rt_rq)
+{
+	BUG_ON(!is_dl_group(rt_rq));
+
+	return rt_rq->tg->dl_se[cpu_of(rt_rq->rq)];
+}
 #else
 static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
 {
@@ -3101,6 +3117,16 @@ static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
 
 	return &rq->rt;
 }
+
+static inline int is_dl_group(struct rt_rq *rt_rq)
+{
+	return 0;
+}
+
+static inline struct sched_dl_entity *dl_group_of(struct rt_rq *rt_rq)
+{
+	return NULL;
+}
 #endif
 
 DEFINE_LOCK_GUARD_2(double_rq_lock, struct rq,
-- 
2.51.0