[RFC PATCH v6 19/25] sched/rt: Remove old RT_GROUP_SCHED data structures

[Yuri Andriaccio <yurand2000@gmail.com>]

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

Completely remove the old RT_GROUP_SCHED's functions and data structures:

- Remove the fields back and my_q from sched_rt_entity.
- Remove the rt_bandwidth data structure.
- Remove the field rt_bandwidth from task_group.
- Remove the rt_bandwidth_enabled function.
- Remove the fields rt_queued, rt_throttled, rt_time, rt_runtime,
  rt_runtime_lock and rt_nr_boosted from rt_rq.

All of the removed fields and data are similarly represented in previously
added fields in rq, rt_rq, dl_bandwidth and in the dl server themselves.

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>
---
 include/linux/sched.h |  3 ---
 kernel/sched/sched.h  | 33 ---------------------------------
 2 files changed, 36 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0021069581c2..e934ec9fc3a9 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -628,12 +628,9 @@ struct sched_rt_entity {
 	unsigned short			on_rq;
 	unsigned short			on_list;

-	struct sched_rt_entity		*back;
 #ifdef CONFIG_RT_GROUP_SCHED
 	/* rq on which this entity is (to be) queued: */
 	struct rt_rq			*rt_rq;
-	/* rq "owned" by this entity/group: */
-	struct rt_rq			*my_q;
 #endif
 } __randomize_layout;

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 394f40dc26db..53248cbbeaf8 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -313,15 +313,6 @@ struct rt_prio_array {
 	struct list_head queue[MAX_RT_PRIO];
 };

-struct rt_bandwidth {
-	/* nests inside the rq lock: */
-	raw_spinlock_t		rt_runtime_lock;
-	ktime_t			rt_period;
-	u64			rt_runtime;
-	struct hrtimer		rt_period_timer;
-	unsigned int		rt_period_active;
-};
-
 struct dl_bandwidth {
 	raw_spinlock_t		dl_runtime_lock;
 	u64			dl_runtime;
@@ -343,12 +334,6 @@ static inline int dl_bandwidth_enabled(void)
  *  - cache the fraction of bandwidth that is currently allocated in
  *    each root domain;
  *
- * This is all done in the data structure below. It is similar to the
- * one used for RT-throttling (rt_bandwidth), with the main difference
- * that, since here we are only interested in admission control, we
- * do not decrease any runtime while the group "executes", neither we
- * need a timer to replenish it.
- *
  * With respect to SMP, bandwidth is given on a per root domain basis,
  * meaning that:
  *  - bw (< 100%) is the deadline bandwidth of each CPU;
@@ -511,11 +496,9 @@ struct task_group {
 	 * different deadline server, and a runqueue per CPU. All the dl-servers
 	 * share the same dl_bandwidth object.
 	 */
-	struct sched_rt_entity	**rt_se;
 	struct sched_dl_entity	**dl_se;
 	struct rt_rq		**rt_rq;

-	struct rt_bandwidth	rt_bandwidth;
 	struct dl_bandwidth	dl_bandwidth;
 #endif

@@ -842,11 +825,6 @@ struct scx_rq {
 };
 #endif /* CONFIG_SCHED_CLASS_EXT */

-static inline int rt_bandwidth_enabled(void)
-{
-	return 0;
-}
-
 /* RT IPI pull logic requires IRQ_WORK */
 #if defined(CONFIG_IRQ_WORK) && defined(CONFIG_SMP)
 # define HAVE_RT_PUSH_IPI
@@ -864,17 +842,6 @@ struct rt_rq {
 	bool			overloaded;
 	struct plist_head	pushable_tasks;

-	int			rt_queued;
-
-#ifdef CONFIG_RT_GROUP_SCHED
-	int			rt_throttled;
-	u64			rt_time; /* consumed RT time, goes up in update_curr_rt */
-	u64			rt_runtime; /* allotted RT time, "slice" from rt_bandwidth, RT sharing/balancing */
-	/* Nests inside the rq lock: */
-	raw_spinlock_t		rt_runtime_lock;
-
-	unsigned int		rt_nr_boosted;
-#endif
 #ifdef CONFIG_CGROUP_SCHED
 	struct task_group	*tg; /* this tg has "this" rt_rq on given CPU for runnable entities */
 #endif
--
2.54.0