Re: [PATCH 07/15] sched_ext: Wrap deferred_reenq_local_node into a struct

[Emil Tsalapatis]

On Fri Mar 6, 2026 at 2:06 PM EST, Tejun Heo wrote:
> Wrap the deferred_reenq_local_node list_head into struct
> scx_deferred_reenq_local. More fields will be added and this allows using a
> shorthand pointer to access them.
>
> No functional change.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>

Reviewed-by: Emil Tsalapatis <emil@xxxxxxxxxxxxxxx>

> ---
>  kernel/sched/ext.c          | 22 +++++++++++++---------
>  kernel/sched/ext_internal.h |  6 +++++-
>  2 files changed, 18 insertions(+), 10 deletions(-)
>
> diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
> index ffccaf04e34d..80d1e6ccc326 100644
> --- a/kernel/sched/ext.c
> +++ b/kernel/sched/ext.c
> @@ -3648,15 +3648,19 @@ static void process_deferred_reenq_locals(struct rq *rq)
>  		struct scx_sched *sch;
>  
>  		scoped_guard (raw_spinlock, &rq->scx.deferred_reenq_lock) {
> -			struct scx_sched_pcpu *sch_pcpu =
> +			struct scx_deferred_reenq_local *drl =
>  				list_first_entry_or_null(&rq->scx.deferred_reenq_locals,
> -							 struct scx_sched_pcpu,
> -							 deferred_reenq_local_node);
> -			if (!sch_pcpu)
> +							 struct scx_deferred_reenq_local,
> +							 node);
> +			struct scx_sched_pcpu *sch_pcpu;
> +
> +			if (!drl)
>  				return;
>  
> +			sch_pcpu = container_of(drl, struct scx_sched_pcpu,
> +						deferred_reenq_local);
>  			sch = sch_pcpu->sch;
> -			list_del_init(&sch_pcpu->deferred_reenq_local_node);
> +			list_del_init(&drl->node);
>  		}
>  
>  		reenq_local(sch, rq);
> @@ -4200,7 +4204,7 @@ static void scx_sched_free_rcu_work(struct work_struct *work)
>  	for_each_possible_cpu(cpu) {
>  		struct scx_sched_pcpu *pcpu = per_cpu_ptr(sch->pcpu, cpu);
>  
> -		WARN_ON_ONCE(!list_empty(&pcpu->deferred_reenq_local_node));
> +		WARN_ON_ONCE(!list_empty(&pcpu->deferred_reenq_local.node));
>  	}
>  
>  	free_percpu(sch->pcpu);
> @@ -5813,7 +5817,7 @@ static struct scx_sched *scx_alloc_and_add_sched(struct sched_ext_ops *ops,
>  		struct scx_sched_pcpu *pcpu = per_cpu_ptr(sch->pcpu, cpu);
>  
>  		pcpu->sch = sch;
> -		INIT_LIST_HEAD(&pcpu->deferred_reenq_local_node);
> +		INIT_LIST_HEAD(&pcpu->deferred_reenq_local.node);
>  	}
>  
>  	sch->helper = kthread_run_worker(0, "sched_ext_helper");
> @@ -8391,8 +8395,8 @@ __bpf_kfunc void scx_bpf_reenqueue_local___v2(const struct bpf_prog_aux *aux)
>  	scoped_guard (raw_spinlock, &rq->scx.deferred_reenq_lock) {
>  		struct scx_sched_pcpu *pcpu = this_cpu_ptr(sch->pcpu);
>  
> -		if (list_empty(&pcpu->deferred_reenq_local_node))
> -			list_move_tail(&pcpu->deferred_reenq_local_node,
> +		if (list_empty(&pcpu->deferred_reenq_local.node))
> +			list_move_tail(&pcpu->deferred_reenq_local.node,
>  				       &rq->scx.deferred_reenq_locals);
>  	}
>  
> diff --git a/kernel/sched/ext_internal.h b/kernel/sched/ext_internal.h
> index 80d40a9c5ad9..1a8d61097cab 100644
> --- a/kernel/sched/ext_internal.h
> +++ b/kernel/sched/ext_internal.h
> @@ -954,6 +954,10 @@ struct scx_dsp_ctx {
>  	struct scx_dsp_buf_ent	buf[];
>  };
>  
> +struct scx_deferred_reenq_local {
> +	struct list_head	node;
> +};
> +
>  struct scx_sched_pcpu {
>  	struct scx_sched	*sch;
>  	u64			flags;	/* protected by rq lock */
> @@ -965,7 +969,7 @@ struct scx_sched_pcpu {
>  	 */
>  	struct scx_event_stats	event_stats;
>  
> -	struct list_head	deferred_reenq_local_node;
> +	struct scx_deferred_reenq_local deferred_reenq_local;
>  	struct scx_dispatch_q	bypass_dsq;
>  #ifdef CONFIG_EXT_SUB_SCHED
>  	u32			bypass_host_seq;