Re: [PATCH 1/4] tools/sched_ext: Strip compatibility macros for cgroup and dispatch APIs

[Andrea Righi <arighi@nvidia.com>]

On Mon, Oct 06, 2025 at 03:51:44PM -1000, Tejun Heo wrote:
> Enough time has passed since the introduction of scx_bpf_task_cgroup() and
> the scx_bpf_dispatch* -> scx_bpf_dsq* kfunc renaming. Strip the compatibility
> macros.
> 
> Signed-off-by: Tejun Heo <tj@kernel.org>

Acked-by: Andrea Righi <arighi@nvidia.com>

Thanks,
-Andrea

> ---
>  tools/sched_ext/include/scx/compat.bpf.h | 108 +----------------------
>  tools/sched_ext/scx_flatcg.bpf.c         |  10 +--
>  tools/sched_ext/scx_qmap.bpf.c           |  14 ++-
>  3 files changed, 12 insertions(+), 120 deletions(-)
> 
> diff --git a/tools/sched_ext/include/scx/compat.bpf.h b/tools/sched_ext/include/scx/compat.bpf.h
> index dd9144624dc9..d979f16a3ae2 100644
> --- a/tools/sched_ext/include/scx/compat.bpf.h
> +++ b/tools/sched_ext/include/scx/compat.bpf.h
> @@ -15,121 +15,17 @@
>  	__ret;									\
>  })
>  
> -/* v6.12: 819513666966 ("sched_ext: Add cgroup support") */
> -#define __COMPAT_scx_bpf_task_cgroup(p)						\
> -	(bpf_ksym_exists(scx_bpf_task_cgroup) ?					\
> -	 scx_bpf_task_cgroup((p)) : NULL)
> -
>  /*
> - * v6.13: The verb `dispatch` was too overloaded and confusing. kfuncs are
> - * renamed to unload the verb.
> - *
> - * Build error is triggered if old names are used. New binaries work with both
> - * new and old names. The compat macros will be removed on v6.15 release.
> + * v6.15: 950ad93df2fc ("bpf: add kfunc for populating cpumask bits")
>   *
> - * scx_bpf_dispatch_from_dsq() and friends were added during v6.12 by
> - * 4c30f5ce4f7a ("sched_ext: Implement scx_bpf_dispatch[_vtime]_from_dsq()").
> - * Preserve __COMPAT macros until v6.15.
> + * Compat macro will be dropped on v6.19 release.
>   */
> -void scx_bpf_dispatch___compat(struct task_struct *p, u64 dsq_id, u64 slice, u64 enq_flags) __ksym __weak;
> -void scx_bpf_dispatch_vtime___compat(struct task_struct *p, u64 dsq_id, u64 slice, u64 vtime, u64 enq_flags) __ksym __weak;
> -bool scx_bpf_consume___compat(u64 dsq_id) __ksym __weak;
> -void scx_bpf_dispatch_from_dsq_set_slice___compat(struct bpf_iter_scx_dsq *it__iter, u64 slice) __ksym __weak;
> -void scx_bpf_dispatch_from_dsq_set_vtime___compat(struct bpf_iter_scx_dsq *it__iter, u64 vtime) __ksym __weak;
> -bool scx_bpf_dispatch_from_dsq___compat(struct bpf_iter_scx_dsq *it__iter, struct task_struct *p, u64 dsq_id, u64 enq_flags) __ksym __weak;
> -bool scx_bpf_dispatch_vtime_from_dsq___compat(struct bpf_iter_scx_dsq *it__iter, struct task_struct *p, u64 dsq_id, u64 enq_flags) __ksym __weak;
>  int bpf_cpumask_populate(struct cpumask *dst, void *src, size_t src__sz) __ksym __weak;
>  
> -#define scx_bpf_dsq_insert(p, dsq_id, slice, enq_flags)				\
> -	(bpf_ksym_exists(scx_bpf_dsq_insert) ?					\
> -	 scx_bpf_dsq_insert((p), (dsq_id), (slice), (enq_flags)) :		\
> -	 scx_bpf_dispatch___compat((p), (dsq_id), (slice), (enq_flags)))
> -
> -#define scx_bpf_dsq_insert_vtime(p, dsq_id, slice, vtime, enq_flags)		\
> -	(bpf_ksym_exists(scx_bpf_dsq_insert_vtime) ?				\
> -	 scx_bpf_dsq_insert_vtime((p), (dsq_id), (slice), (vtime), (enq_flags)) : \
> -	 scx_bpf_dispatch_vtime___compat((p), (dsq_id), (slice), (vtime), (enq_flags)))
> -
> -#define scx_bpf_dsq_move_to_local(dsq_id)					\
> -	(bpf_ksym_exists(scx_bpf_dsq_move_to_local) ?				\
> -	 scx_bpf_dsq_move_to_local((dsq_id)) :					\
> -	 scx_bpf_consume___compat((dsq_id)))
> -
> -#define __COMPAT_scx_bpf_dsq_move_set_slice(it__iter, slice)			\
> -	(bpf_ksym_exists(scx_bpf_dsq_move_set_slice) ?				\
> -	 scx_bpf_dsq_move_set_slice((it__iter), (slice)) :			\
> -	 (bpf_ksym_exists(scx_bpf_dispatch_from_dsq_set_slice___compat) ?	\
> -	  scx_bpf_dispatch_from_dsq_set_slice___compat((it__iter), (slice)) :	\
> -	  (void)0))
> -
> -#define __COMPAT_scx_bpf_dsq_move_set_vtime(it__iter, vtime)			\
> -	(bpf_ksym_exists(scx_bpf_dsq_move_set_vtime) ?				\
> -	 scx_bpf_dsq_move_set_vtime((it__iter), (vtime)) :			\
> -	 (bpf_ksym_exists(scx_bpf_dispatch_from_dsq_set_vtime___compat) ?	\
> -	  scx_bpf_dispatch_from_dsq_set_vtime___compat((it__iter), (vtime)) :	\
> -	  (void) 0))
> -
> -#define __COMPAT_scx_bpf_dsq_move(it__iter, p, dsq_id, enq_flags)		\
> -	(bpf_ksym_exists(scx_bpf_dsq_move) ?					\
> -	 scx_bpf_dsq_move((it__iter), (p), (dsq_id), (enq_flags)) :		\
> -	 (bpf_ksym_exists(scx_bpf_dispatch_from_dsq___compat) ?			\
> -	  scx_bpf_dispatch_from_dsq___compat((it__iter), (p), (dsq_id), (enq_flags)) : \
> -	  false))
> -
> -#define __COMPAT_scx_bpf_dsq_move_vtime(it__iter, p, dsq_id, enq_flags)		\
> -	(bpf_ksym_exists(scx_bpf_dsq_move_vtime) ?				\
> -	 scx_bpf_dsq_move_vtime((it__iter), (p), (dsq_id), (enq_flags)) :	\
> -	 (bpf_ksym_exists(scx_bpf_dispatch_vtime_from_dsq___compat) ?		\
> -	  scx_bpf_dispatch_vtime_from_dsq___compat((it__iter), (p), (dsq_id), (enq_flags)) : \
> -	  false))
> -
>  #define __COMPAT_bpf_cpumask_populate(cpumask, src, size__sz)		\
>  	(bpf_ksym_exists(bpf_cpumask_populate) ?			\
>  	 (bpf_cpumask_populate(cpumask, src, size__sz)) : -EOPNOTSUPP)
>  
> -#define scx_bpf_dispatch(p, dsq_id, slice, enq_flags)				\
> -	_Static_assert(false, "scx_bpf_dispatch() renamed to scx_bpf_dsq_insert()")
> -
> -#define scx_bpf_dispatch_vtime(p, dsq_id, slice, vtime, enq_flags)		\
> -	_Static_assert(false, "scx_bpf_dispatch_vtime() renamed to scx_bpf_dsq_insert_vtime()")
> -
> -#define scx_bpf_consume(dsq_id) ({						\
> -	_Static_assert(false, "scx_bpf_consume() renamed to scx_bpf_dsq_move_to_local()"); \
> -	false;									\
> -})
> -
> -#define scx_bpf_dispatch_from_dsq_set_slice(it__iter, slice)		\
> -	_Static_assert(false, "scx_bpf_dispatch_from_dsq_set_slice() renamed to scx_bpf_dsq_move_set_slice()")
> -
> -#define scx_bpf_dispatch_from_dsq_set_vtime(it__iter, vtime)		\
> -	_Static_assert(false, "scx_bpf_dispatch_from_dsq_set_vtime() renamed to scx_bpf_dsq_move_set_vtime()")
> -
> -#define scx_bpf_dispatch_from_dsq(it__iter, p, dsq_id, enq_flags) ({	\
> -	_Static_assert(false, "scx_bpf_dispatch_from_dsq() renamed to scx_bpf_dsq_move()"); \
> -	false;									\
> -})
> -
> -#define scx_bpf_dispatch_vtime_from_dsq(it__iter, p, dsq_id, enq_flags) ({  \
> -	_Static_assert(false, "scx_bpf_dispatch_vtime_from_dsq() renamed to scx_bpf_dsq_move_vtime()"); \
> -	false;									\
> -})
> -
> -#define __COMPAT_scx_bpf_dispatch_from_dsq_set_slice(it__iter, slice)		\
> -	_Static_assert(false, "__COMPAT_scx_bpf_dispatch_from_dsq_set_slice() renamed to __COMPAT_scx_bpf_dsq_move_set_slice()")
> -
> -#define __COMPAT_scx_bpf_dispatch_from_dsq_set_vtime(it__iter, vtime)		\
> -	_Static_assert(false, "__COMPAT_scx_bpf_dispatch_from_dsq_set_vtime() renamed to __COMPAT_scx_bpf_dsq_move_set_vtime()")
> -
> -#define __COMPAT_scx_bpf_dispatch_from_dsq(it__iter, p, dsq_id, enq_flags) ({	\
> -	_Static_assert(false, "__COMPAT_scx_bpf_dispatch_from_dsq() renamed to __COMPAT_scx_bpf_dsq_move()"); \
> -	false;									\
> -})
> -
> -#define __COMPAT_scx_bpf_dispatch_vtime_from_dsq(it__iter, p, dsq_id, enq_flags) ({  \
> -	_Static_assert(false, "__COMPAT_scx_bpf_dispatch_vtime_from_dsq() renamed to __COMPAT_scx_bpf_dsq_move_vtime()"); \
> -	false;									\
> -})
> -
>  /**
>   * __COMPAT_is_enq_cpu_selected - Test if SCX_ENQ_CPU_SELECTED is on
>   * in a compatible way. We will preserve this __COMPAT helper until v6.16.
> diff --git a/tools/sched_ext/scx_flatcg.bpf.c b/tools/sched_ext/scx_flatcg.bpf.c
> index 2c720e3ecad5..43126858b8e4 100644
> --- a/tools/sched_ext/scx_flatcg.bpf.c
> +++ b/tools/sched_ext/scx_flatcg.bpf.c
> @@ -382,7 +382,7 @@ void BPF_STRUCT_OPS(fcg_enqueue, struct task_struct *p, u64 enq_flags)
>  		return;
>  	}
>  
> -	cgrp = __COMPAT_scx_bpf_task_cgroup(p);
> +	cgrp = scx_bpf_task_cgroup(p);
>  	cgc = find_cgrp_ctx(cgrp);
>  	if (!cgc)
>  		goto out_release;
> @@ -508,7 +508,7 @@ void BPF_STRUCT_OPS(fcg_runnable, struct task_struct *p, u64 enq_flags)
>  {
>  	struct cgroup *cgrp;
>  
> -	cgrp = __COMPAT_scx_bpf_task_cgroup(p);
> +	cgrp = scx_bpf_task_cgroup(p);
>  	update_active_weight_sums(cgrp, true);
>  	bpf_cgroup_release(cgrp);
>  }
> @@ -521,7 +521,7 @@ void BPF_STRUCT_OPS(fcg_running, struct task_struct *p)
>  	if (fifo_sched)
>  		return;
>  
> -	cgrp = __COMPAT_scx_bpf_task_cgroup(p);
> +	cgrp = scx_bpf_task_cgroup(p);
>  	cgc = find_cgrp_ctx(cgrp);
>  	if (cgc) {
>  		/*
> @@ -564,7 +564,7 @@ void BPF_STRUCT_OPS(fcg_stopping, struct task_struct *p, bool runnable)
>  	if (!taskc->bypassed_at)
>  		return;
>  
> -	cgrp = __COMPAT_scx_bpf_task_cgroup(p);
> +	cgrp = scx_bpf_task_cgroup(p);
>  	cgc = find_cgrp_ctx(cgrp);
>  	if (cgc) {
>  		__sync_fetch_and_add(&cgc->cvtime_delta,
> @@ -578,7 +578,7 @@ void BPF_STRUCT_OPS(fcg_quiescent, struct task_struct *p, u64 deq_flags)
>  {
>  	struct cgroup *cgrp;
>  
> -	cgrp = __COMPAT_scx_bpf_task_cgroup(p);
> +	cgrp = scx_bpf_task_cgroup(p);
>  	update_active_weight_sums(cgrp, false);
>  	bpf_cgroup_release(cgrp);
>  }
> diff --git a/tools/sched_ext/scx_qmap.bpf.c b/tools/sched_ext/scx_qmap.bpf.c
> index 3072b593f898..c67dac78a4c6 100644
> --- a/tools/sched_ext/scx_qmap.bpf.c
> +++ b/tools/sched_ext/scx_qmap.bpf.c
> @@ -320,12 +320,9 @@ static bool dispatch_highpri(bool from_timer)
>  
>  		if (tctx->highpri) {
>  			/* exercise the set_*() and vtime interface too */
> -			__COMPAT_scx_bpf_dsq_move_set_slice(
> -				BPF_FOR_EACH_ITER, slice_ns * 2);
> -			__COMPAT_scx_bpf_dsq_move_set_vtime(
> -				BPF_FOR_EACH_ITER, highpri_seq++);
> -			__COMPAT_scx_bpf_dsq_move_vtime(
> -				BPF_FOR_EACH_ITER, p, HIGHPRI_DSQ, 0);
> +			scx_bpf_dsq_move_set_slice(BPF_FOR_EACH_ITER, slice_ns * 2);
> +			scx_bpf_dsq_move_set_vtime(BPF_FOR_EACH_ITER, highpri_seq++);
> +			scx_bpf_dsq_move_vtime(BPF_FOR_EACH_ITER, p, HIGHPRI_DSQ, 0);
>  		}
>  	}
>  
> @@ -342,9 +339,8 @@ static bool dispatch_highpri(bool from_timer)
>  		else
>  			cpu = scx_bpf_pick_any_cpu(p->cpus_ptr, 0);
>  
> -		if (__COMPAT_scx_bpf_dsq_move(BPF_FOR_EACH_ITER, p,
> -					      SCX_DSQ_LOCAL_ON | cpu,
> -					      SCX_ENQ_PREEMPT)) {
> +		if (scx_bpf_dsq_move(BPF_FOR_EACH_ITER, p, SCX_DSQ_LOCAL_ON | cpu,
> +				     SCX_ENQ_PREEMPT)) {
>  			if (cpu == this_cpu) {
>  				dispatched = true;
>  				__sync_fetch_and_add(&nr_expedited_local, 1);
> -- 
> 2.51.0
>