[RFC PATCH v2 1/7] sched/fair: Add related data structure for task based throttle

Aaron Lu
2025-04-09T12:08:11Z

From: Valentin Schneider <vschneid@redhat.com>

Add related data structures for this new throttle functionality.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Aaron Lu <ziqianlu@bytedance.com>
---
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 f96ac19828934..0b55c79fee209 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -880,6 +880,10 @@ 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 79692f85643fe..3b8735bc527da 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4492,6 +4492,9 @@ 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 0c19459c80422..894202d232efd 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5823,6 +5823,18 @@ 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 c5a6a503eb6de..921527327f107 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2703,6 +2703,8 @@ 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