[RFC PATCH 1/7] sched/fair: Add related data structure for task based throttle

[Aaron Lu]

From: Valentin Schneider <vschneid@xxxxxxxxxx>

Add related data structures for this new throttle functionality.

[aaronlu: extracted from Valentin's original patches]
Signed-off-by: Valentin Schneider <vschneid@xxxxxxxxxx>
Signed-off-by: Aaron Lu <ziqianlu@xxxxxxxxxxxxx>
---
 include/linux/sched.h |  4 ++++
 kernel/sched/core.c   |  3 +++
 kernel/sched/fair.c   | 12 ++++++++++++
 kernel/sched/sched.h  |  2 ++
 4 files changed, 21 insertions(+)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 9632e3318e0d6..eec9087232660 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -858,6 +858,10 @@ struct task_struct {

 #ifdef CONFIG_CGROUP_SCHED
 	struct task_group		*sched_task_group;
+#ifdef CONFIG_CFS_BANDWIDTH
+	struct callback_head		sched_throttle_work;
+	struct list_head		throttle_node;
+#endif
 #endif


diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 621cfc731c5be..56e2ea14ac3b4 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4493,6 +4493,9 @@ static void __sched_fork(unsigned long
clone_flags, struct task_struct *p)

 #ifdef CONFIG_FAIR_GROUP_SCHED
 	p->se.cfs_rq			= NULL;
+#ifdef CONFIG_CFS_BANDWIDTH
+	init_cfs_throttle_work(p);
+#endif
 #endif

 #ifdef CONFIG_SCHEDSTATS
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9dafb374d76d9..60eb5329bf526 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5832,6 +5832,18 @@ static inline int throttled_lb_pair(struct
task_group *tg,
 	       throttled_hierarchy(dest_cfs_rq);
 }

+static void throttle_cfs_rq_work(struct callback_head *work)
+{
+}
+
+void init_cfs_throttle_work(struct task_struct *p)
+{
+	init_task_work(&p->sched_throttle_work, throttle_cfs_rq_work);
+	/* Protect against double add, see throttle_cfs_rq() and
throttle_cfs_rq_work() */
+	p->sched_throttle_work.next = &p->sched_throttle_work;
+	INIT_LIST_HEAD(&p->throttle_node);
+}
+
 static int tg_unthrottle_up(struct task_group *tg, void *data)
 {
 	struct rq *rq = data;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 023b844159c94..c8bfa3d708081 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2724,6 +2724,8 @@ extern bool sched_rt_bandwidth_account(struct
rt_rq *rt_rq);

 extern void init_dl_entity(struct sched_dl_entity *dl_se);

+extern void init_cfs_throttle_work(struct task_struct *p);
+
 #define BW_SHIFT		20
 #define BW_UNIT			(1 << BW_SHIFT)
 #define RATIO_SHIFT		8
-- 
2.39.5