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

Add dl_init_tg to initialize and/or update a rt-cgroup dl_server and to
also account the allocated bandwidth.

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/deadline.c | 33 +++++++++++++++++++++++++++++++++
 kernel/sched/sched.h    |  1 +
 2 files changed, 34 insertions(+)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 5c8fe80b585..34a1494d782 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -340,6 +340,39 @@ 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(dl_se->dl_rq, struct rq, dl);
+	int is_active;
+	u64 new_bw;
+
+	raw_spin_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(dl_se->dl_period, dl_se->dl_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);
+
+	raw_spin_rq_unlock_irq(rq);
+}
+#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 d433abe1c9c..9853f321363 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -394,6 +394,7 @@ extern void dl_server_init(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq,
 		    dl_server_has_tasks_f has_tasks,
 		    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 dl_server_update_idle_time(struct rq *rq,
 		    struct task_struct *p);
-- 
2.51.0

Hello,

On 29/09/25 11:22, Yuri Andriaccio wrote:
> From: luca abeni <luca.abeni@santannapisa.it>
> 
> Add dl_init_tg to initialize and/or update a rt-cgroup dl_server and to
> also account the allocated bandwidth.
> 
> 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/deadline.c | 33 +++++++++++++++++++++++++++++++++
>  kernel/sched/sched.h    |  1 +
>  2 files changed, 34 insertions(+)
> 
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 5c8fe80b585..34a1494d782 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -340,6 +340,39 @@ 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)

This is not called from anywhere at this point, is it? I wonder if we
want to introduce dead code for later usage or if it would make more
sense to introduce it together with the calling sites.

> +{
> +	struct rq *rq = container_of(dl_se->dl_rq, struct rq, dl);
> +	int is_active;
> +	u64 new_bw;
> +
> +	raw_spin_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(dl_se->dl_period, dl_se->dl_runtime);

Is this correct? Not sure yet where/how dl_init_tg() is called, but
don't we want to compute new_bw using rt_runtime and rt_period?

Thanks,
Juri