[RFC PATCH v7 10/29] sched/deadline: Add dl_init_tg

[Yuri Andriaccio]

From: luca abeni <luca.abeni@xxxxxxxxxxxxxxx>

Add dl_init_tg to initialize and/or update a rt-cgroup dl_server and to
also account the allocated bandwidth. This function is currently unhooked
and will be later used to allocate bandwidth to rt-cgroups.

Add lock guard for raw_spin_rq_lock_irq for cleaner code.

Co-developed-by: Alessio Balsini <a.balsini@xxxxxxxx>
Signed-off-by: Alessio Balsini <a.balsini@xxxxxxxx>
Co-developed-by: Andrea Parri <parri.andrea@xxxxxxxxx>
Signed-off-by: Andrea Parri <parri.andrea@xxxxxxxxx>
Co-developed-by: Yuri Andriaccio <yurand2000@xxxxxxxxx>
Signed-off-by: Yuri Andriaccio <yurand2000@xxxxxxxxx>
Signed-off-by: luca abeni <luca.abeni@xxxxxxxxxxxxxxx>
---
 kernel/sched/deadline.c | 31 +++++++++++++++++++++++++++++++
 kernel/sched/sched.h    |  1 +
 2 files changed, 32 insertions(+)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index aceeb28d4b2b..b6b5fcb15f43 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -335,6 +335,37 @@ void cancel_inactive_timer(struct sched_dl_entity *dl_se)
 	cancel_dl_timer(dl_se, &dl_se->inactive_timer);
 }
 
+#ifdef CONFIG_RT_GROUP_SCHED
+void dl_init_tg(struct sched_dl_entity *dl_se, u64 rt_runtime, u64 rt_period)
+{
+	struct rq *rq = container_of_const(dl_se->dl_rq, struct rq, dl);
+	int is_active;
+	u64 new_bw;
+
+	guard(rq_lock_irq)(rq);
+	is_active = dl_se->my_q->rt.rt_nr_running > 0;
+
+	update_rq_clock(rq);
+	dl_server_stop(dl_se);
+
+	new_bw = to_ratio(rt_period, rt_runtime);
+	dl_rq_change_utilization(rq, dl_se, new_bw);
+
+	dl_se->dl_runtime  = rt_runtime;
+	dl_se->dl_deadline = rt_period;
+	dl_se->dl_period   = rt_period;
+
+	dl_se->runtime = 0;
+	dl_se->deadline = 0;
+
+	dl_se->dl_bw = new_bw;
+	dl_se->dl_density = new_bw;
+
+	if (is_active)
+		dl_server_start(dl_se);
+}
+#endif
+
 static void dl_change_utilization(struct task_struct *p, u64 new_bw)
 {
 	WARN_ON_ONCE(p->dl.flags & SCHED_FLAG_SUGOV);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index e8a62b37a72d..b55ce13412d6 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -425,6 +425,7 @@ extern void dl_server_init(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq,
 		    struct rq *served_rq,
 		    dl_server_pick_f pick_task);
 extern void sched_init_dl_servers(void);
+extern void dl_init_tg(struct sched_dl_entity *dl_se, u64 rt_runtime, u64 rt_period);
 
 extern void fair_server_init(struct rq *rq);
 extern void ext_server_init(struct rq *rq);
-- 
2.56.0