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

[Chengming Zhou <chengming.zhou@linux.dev>]

On 2025/5/20 18:41, Aaron Lu wrote:
> 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>

Looks good to me.

Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>

Thanks!

> ---
>   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 b98195991031c..055f3782eeaee 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -879,6 +879,10 @@ 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 bece0ba6f5b3a..b7ca7cefee54e 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -4499,6 +4499,9 @@ 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 eb5a2572b4f8b..75bf6186a5137 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -5825,6 +5825,18 @@ 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