[PATCH v2 1/5] sched/fair: Add related data structure for task based throttle

Aaron Lu
2025-06-18T08:20:13Z

From: Valentin Schneider <vschneid@redhat.com>

Add related data structures for this new throttle functionality.

Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Aaron Lu <ziqianlu@bytedance.com>
---
include/linux/sched.h | 5 +++++
kernel/sched/core.c | 3 +++
kernel/sched/fair.c | 13 +++++++++++++
kernel/sched/sched.h | 3 +++
4 files changed, 24 insertions(+)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index eec6b225e9d14..95f2453b17222 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -874,6 +874,11 @@ 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;
+ bool throttled;
+#endif
#endif

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index a03c3c1d7f50a..afb4da893c02f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4446,6 +4446,9 @@ 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 6b17d3da034af..f7b8597bc95ac 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5757,6 +5757,18 @@ 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;
@@ -6488,6 +6500,7 @@ static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
cfs_rq->runtime_enabled = 0;
INIT_LIST_HEAD(&cfs_rq->throttled_list);
INIT_LIST_HEAD(&cfs_rq->throttled_csd_list);
+ INIT_LIST_HEAD(&cfs_rq->throttled_limbo_list);
}

void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index c323d015486cf..fa78c0c3efe39 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -728,6 +728,7 @@ struct cfs_rq {
int throttle_count;
struct list_head throttled_list;
struct list_head throttled_csd_list;
+ struct list_head throttled_limbo_list;
#endif /* CONFIG_CFS_BANDWIDTH */
#endif /* CONFIG_FAIR_GROUP_SCHED */
};
@@ -2627,6 +2628,8 @@ 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